BACKGROUND Patients with middle and advanced hepatocellular carcinoma(HCC)frequently experience significant anxiety and depression,severely affecting their quality of life.AIM To examine the anxiety and depression sta...BACKGROUND Patients with middle and advanced hepatocellular carcinoma(HCC)frequently experience significant anxiety and depression,severely affecting their quality of life.AIM To examine the anxiety and depression status of patients with middle and advanced HCC,the influencing factors,and the correlation between these psychological factors and quality of life.METHODS We collected baseline data from 100 patients with HCC,assessing anxiety and depression levels using the Hamilton Anxiety Rating Scale(HAMA)and Hamilton Depression Rating Scale(HAMD).Quality of life was evaluated with the Functional Assessment of Cancer Therapy-Hepatobiliary Questionnaire.Multivariate logistic regression analyzed clinical and psychosocial factors affecting anxiety and depression,while Pearson correlation assessed relationships among HAMA,HAMD,and Functional Assessment of Cancer Therapy-Hepatobiliary Questionnaire scores.RESULTS Results indicated that 64%of patients exhibited anxiety and 65%showed depression symptoms.Key influencing factors included Barcelona Clinic Liver Cancer C stage,multiple tumors,social support,prior treatments(such as liver resection and transcatheter arterial chemoembolization/hepatic artery infusion chemotherapy),as well as HAMA and HAMD scores.Anxiety and depression correlated negatively with quality of life,with coefficients of-0.671 and-0.575 for HAMA and HAMD,respectively.CONCLUSION Anxiety and depression are prevalent among patients with middle and advanced HCC,impacting quality of life.This underscores the need for psychological health considerations in liver cancer treatment and establishing psychological interventions is essential.展开更多
Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of m...Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision,and the anisotropic nature of silicon is frequently overlooked.To address these issues,this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs.The optimized square-lattice PnC slabs,featuring a rounded-cross structure oriented along the`110e directions of silicon,achieve an impressive relative bandgap(RBG)width of 82.2%for in-plane modes.When further tilted by 15° from the (100) directions within the(001)plane,the optimal RBG width is expanded to 91.4%.We fabricate and characterize thin-film piezoelectric-on-silicon LVRs,with or without optimized 2D PnC slabs.The presence of PnC slabs around anchors increases the series and parallel quality factors Q_(s) and Q_(p) from 2240 to 7118 and from 2237 to 7501,respectively,with the PnC slabs oriented along the`110e directions of silicon.展开更多
We report the world-leading performance of a 1.3 GHz cryomodule equipped with eight 9-cell superconducting radio-frequency cavities that underwent a medium-temperature furnace baking process.During continuous wave hor...We report the world-leading performance of a 1.3 GHz cryomodule equipped with eight 9-cell superconducting radio-frequency cavities that underwent a medium-temperature furnace baking process.During continuous wave horizontal testing,these cavities achieved unprecedented average intrinsic quality factors of 4.0×10^(10)at 20 MV/m and 3.2×10^(10)at 29 MV/m,with no instances of field emission.The cryomodule demonstrates near-complete preservation of ultra-high quality factors and ultra-high accelerating gradients from vertical to horizontal testing,marking a significant milestone in continuous-wave superconducting radio-frequency accelerator technology.This letter presents the cryomodule development experience,includ-ing cavity preparation,cryomodule assembly,degaussing,fast cooldown,and performance testing.展开更多
Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of ro...Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.展开更多
Damped acoustic systems have a limited quality factor due to intrinsic loss.By introducing gain elements,a method to enhance the quality factor of damped systems is proposed based on the concept of bound states in the...Damped acoustic systems have a limited quality factor due to intrinsic loss.By introducing gain elements,a method to enhance the quality factor of damped systems is proposed based on the concept of bound states in the continuum(BICs).The acoustic model under study is a two-port waveguide system installed with two side Helmholtz resonators connected by a coupling tube.Based on the temporal coupled-mode theory,a Hamiltonian matrix with both intrinsic and radiation losses is used to characterize the resonance behavior of the coupled resonators.To achieve a high quality factor,acoustic gain is introduced to compensate the intrinsic loss,leading the Hamiltonian parameters toward a quasi-BIC condition.Numerical simulation demonstrates a gain-assisted and quasi-BIC-supported extremely high quality factor in damped acoustic systems.The concept is further utilized to design a sensor model for particle size detection.The enhanced sensing performance due to high quality factors is numerically demonstrated.The findings suggest potential applications in acoustic sensing and detection devices.展开更多
The Yangtze River economic belt(YREB),China is important to the Chinese economy and for supporting sustainable development.Clarifying the relationship between water quality indices and socioeconomic indicators could h...The Yangtze River economic belt(YREB),China is important to the Chinese economy and for supporting sustainable development.Clarifying the relationship between water quality indices and socioeconomic indicators could help improve aquatic environment management in the YREB and our understanding of the causes and effects of water quality variations in other large river basins.In this study,river water quality,factors affecting water quality,and management strategies,and correlations between water quality indices and socioeconomic indicators in the YREB during the 13th Five-Year Plan period(2016-2020)were assessed.The single-factor evaluation method,constant price for GDP,and correlation analyses were adopted.The results showed that:1)water quality in the YREB improved during the 13th Five-Year Plan period.The number of aquatic environment sections meeting GradeⅠ-Ⅲwater quality standards increased by 13.1%and the number below Grade V decreased by 2.9%.2)The values of 12 indicators in the YREB exceeded relevant standards.The indicators with highest concentreation were the total phosphorus,chemical oxygen demand,ammonia nitrogen,and permanganate index,which were relatively high in downstream regions in Anhui Province,Jiangsu Province,and Shanghai Municipality.3)Ammonia nitrogen,chemical oxygen demand,and total phosphorus emissions per unit area and water extraction per unit area are relatively high in the three downstream regions mentioned above.4)Increased domestic sewage discharges have increased total wastewater discharges in the YREB.5)River water quality in the YREB strongly correlated with population,economic,and water resource indices and less strongly correlated with government investment,agriculture,meteorology,energy,and forestry indices.This confirmed the need to decrease wastewater discharges and non-point-source pollutant emissions.The aquatic environment could be improved by taking reasonable measures to control population growth,adjusting the industrial structure to accelerate industrial transformation and increase the proportion of tertiary industries,and investing in technological innovations to protect the environment.展开更多
A theory based on the superposition principle is developed to uncover the basic physics of wave behavior in a finite grating of N unit cells.The theory reveals that bound states in the continuum(BICs)of infinite quali...A theory based on the superposition principle is developed to uncover the basic physics of wave behavior in a finite grating of N unit cells.The theory reveals that bound states in the continuum(BICs)of infinite quality factor(Q-factor)can be supported by such a grating when perfect reflection is introduced at its boundaries.If geometrical perturbations are introduced into the structure,the dark BICs transform into bright quasi-BICs with finite Q-factor,maintaining spectral characteristics nearly identical to those of quasi-BICs supported by infinite gratings.When the boundaries are replaced with high-reflectivity metallic mirrors,the Q-factor of the resonant mode is reduced to be finite;however,it can be much larger than that in the corresponding nanostructure with open boundaries and can be tuned over a large range by varying the number of unit cells or boundary conditions.展开更多
[Objective] This study aimed to analyze the influence of five cultivation factors including sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount and potash fertilizer amount on the quali...[Objective] This study aimed to analyze the influence of five cultivation factors including sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount and potash fertilizer amount on the quality parameters of Brassica napus hybrid＆ [Method] Statistical analysis on the data from previous studies and our work was carried out [Result] The contents of erucic acid, thioglycoside, oil, oleic acid and linoleic acid were negatively correlated with the sowing date, while the contents of seed protein, palmitic acid, stearic acid and linolenic acid were positively correlated with the sowing date. The total amount of fat and protein, the ratio of unsaturated fatty acid （UFA） to saturated fatty acid （SFA）, the fatty acid （FA） of erucic acid chain, the total amount of oleic acid and linoleic acid were negatively correlated with the sowing date; the UFA content, the unsatu- ration index, the SFA content, the 18-C FA content, and the ratio of UFA to FA in erucic acid chain were positively correlated with the sowing date. The contents of erucic acid, thioglycoside, seed protein, oleic acid, linolenic acid and eicosenoic acid were negatively correlated with the plant density, while the contents of oil, palmitic acid, stearic acid and linoleic acid were positively correlated with the plant density. The total amount of fat and protein （F ＆ P）, and the ratio of UFA to FA in erucic acid chain were negatively correlated with the plant density, while the UFA content, the unsaturation index, the SFA content, the ratio of UFA to SFA, the 18-C FA content, the FA in erucic acid chain, and the total amount of oleic acid and linoleic acid were positively correlated with the plant density. The contents of erucic acid, thioglycoside, oil, protein in milled rapeseed, palmitic acid and eicosenoic acid were negatively correlated with the nitrogen fertilizer amount, while the contents of seed protein, oleic acid, stearic acid, linoleic acid and linolenic acid were posi- tively correlated with the nitrogen fertilizer amount; the total F ＆ P, the unsaturation index and the ratio of UFA to FA in erucic acid chain were positively correlated with the nitrogen fertilizer amount, while the UFA content, the SFA content, the FA in erucic acid chain, the total amount of oleic acid and linoleic acid, the ratio of UFA to SFA, and the 18-C FA content were negatively correlated with the nitrogen fertilizer amount The contents of erucic acid, thioglycoside, seed protein, linoleic acid and linolenic acid were negatively correlated with the potash fertilizer amount, while contents of oil, oleic acid, stearic acid and eicosenoic acid were positively correlated with the potash fertilizer amount; the total F ＆ P, the unsaturation index, the SFA, and the ratio of UFA to FA in erucic acid chain were negatively correlated with the potash fertilizer amount There were negative correlations between the contents of erucic acid, thioglycoside, seed protein, palmitic acid, stearic acid, linoleic acid, linolenic acid and phosphate fertilizer amount; positive correlations between the contents of oil, oleic acid, eicosenoic acid and phosphate fertilizer amount The total UFA, the unsaturation index, the 1843 FA, the SFA, the FA in erucic acid chain, and the ratio of UFA to FA in erucic acid chain were negatively correlated with the phosphate fertilizer amount [Conclusion] This study identified the correlations of the five cultivation factors with the quality parameters of high-quality Brassica napus hybrids, to provide theoretical basis for its cultivation.展开更多
[Objective] This study aimed to analyze the influence of five cultivation factors： sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount and potash fertilizer amount on oil quality and ...[Objective] This study aimed to analyze the influence of five cultivation factors： sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount and potash fertilizer amount on oil quality and stability of Brassica napus hybrids. [Method] Statistical analysis was carried out based on the data from previous studies and our work. [Result] Sowing date had no significant influence on oil quality and stability of B. napus hybrids. The plant density shared a positive correlation with 18-C fatty acid （FA） content, unsaturated fatty acid （UFA） content, total content of linoleic acid and linolenic acid, index of unsaturated fatty acid （IUFA）, so a large plant density can improve the oil quality （by increasing18-C FA content, UFA content, total content of linoleic acid and linolenic acid）, but reduce the oil stability （by increasing IUFA）. The amount of nitrogen fertilizer had no significant influence on the contents of 18-C FA and UFA, but significant positive correlations with the total content of linoleic acid and linolenic acid and IUFA. So, the total content of linoleic acid and linolenic acid can be reduced by increasing nitrogen amount, meanwhile the oil stability was also decreased. Phosphate fertilizer amount did not affect 18-C FA significantly, but was negatively correlated with the UFA content, total content of linoleic acid and linolenic acid, and IUFA. So, increasing the amount of applied phosphate fertilizer can reduce UFA content, total content of linoleic acid and linolenic acid, thereby improving oil stability. Potash fertilizer had no significant influence on the IUFA, a significant positive correlation with 18-C FA content, an insignificant positive correlation with the the UFA content, and a negative correlation with the total content of linoleic acid and linolenic acid. The oil content of rapeseed shared an extremely significant positive correlation with 18-C FA content and UFA content, an negative correlation with the total content of linoleic acid and linolenic acid, and no significant correlation with IUFA. [Conclusion] This study identified the effects of five main cultivation factors on oil quality and stability of B. napus hybrids, and the correlations of oil content with 18-C FA content, UFA content, total content of linoleic acid and linolenic acid, and IUFA.展开更多
Human factors engineering and quality management are different research branches in the field of industrial engineering.A basis for interaction based on the concepts and techniques of human factors engineering and qua...Human factors engineering and quality management are different research branches in the field of industrial engineering.A basis for interaction based on the concepts and techniques of human factors engineering and quality management with some practical examples of cooperative effect is defined in this paper.The specific challenges about the quality management in manufacturing and service are presented to demonstrate that the human factors analysis of quality problems leads to new tends for integrated development.展开更多
The mode frequencies and the quality factors for the equilateral triangular resonator (ETR), the square resonator (SR) and the rhombus resonator (RR) are numerically calculated by the finite difference time domai...The mode frequencies and the quality factors for the equilateral triangular resonator (ETR), the square resonator (SR) and the rhombus resonator (RR) are numerically calculated by the finite difference time domain technique and the Padé approximation. The numerical results show that the resonant modes confined in an equilateral triangular cavity have much higher quality factors than those in the square or the rhombus cavities. The modes in the ETR are totally confined in transverse direction while those in the SR and RR are only partly confined. For the ETR with the side length of 4μm and the refractive index of 3 2, the mode quality factor of about 5 5×10 3 at the wavelength of 1 55μm has been obtained.展开更多
To facilitate investigation of the effect of imperfect elastic dissipation on the propagation of Rayleigh-type channel waves and use of their quality factors in investigations of the properties of coal seams, a simple...To facilitate investigation of the effect of imperfect elastic dissipation on the propagation of Rayleigh-type channel waves and use of their quality factors in investigations of the properties of coal seams, a simple method for calculating the quality factor QR is proposed in this paper. Introduction of complex velocities into the dispersion function allows calculation of the dispersion function of Rayleigh-type channel waves in coal seams. By the control variable method, we analyzed changes in QR with changes in coal seam thickness and P- and S-wave Q-factors within the coal seam and adjacent rock layers. The numerical results show that the trend of the QR curve is consistent with the group velocity curve. The minimum QR value occurs at the Airy phase frequency; the Airy phase frequency decreases as coal seam thickness increases. The value of QR increases with increasing QS2(quality factor for S wave in coal seam). We can compensate for the absorption of Rayleigh-type channel waves using the computed QR curve. Inversion of the QR curve can also be used to predict the thicknesses and lithologies of coal seams.展开更多
The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extrac...The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extraction method based on the energy ratio before and after the wavelet attenuation, named the energy-ratio method（ERM）. The proposed method uses multipoint signal data in the time domain to estimate the wavelet energy without invoking the source wavelet spectrum, which is necessary in conventional Q extraction methods, and is applicable to any source wavelet spectrum; however, it requires high-precision seismic data. Forward zero-offset VSP modeling suggests that the ERM can be used for reliable Q inversion after nonintrinsic attenuation（geometric dispersion, refl ection, and transmission loss） compensation. The application to real zero-offset VSP data shows that the Q values extracted by the ERM and spectral ratio methods are identical, which proves the reliability of the new method.展开更多
The rapid development in Beijing, the capital of China, has resulted in serious air pollution problems. Meanwhile great efforts have been made to improve the air quality, especially since 1998. The variation in air qu...The rapid development in Beijing, the capital of China, has resulted in serious air pollution problems. Meanwhile great efforts have been made to improve the air quality, especially since 1998. The variation in air quality under the interaction of pollution and control in this mega city has attracted much attention. We analyzed the changes in ambient air quality in Beijing since the 1980’s using the Daniel trend test based on data from long-term monitoring stations. The results showed that different pollutants displayed three trends： a decreasing trend, an increasing trend and a flat trend. SO2, dustfall, B[a]P, NO2 and PM10 fit decreasing trend pattern, while NOx showed an increasing trend, and CO, ozone pollution, total suspended particulate （TSP）, as well as Pb fit the flat trend. The cause of the general air pollution in Beijing has changed from being predominantly related to coal burning to mixed traffic exhaust and coal burning related pollution. Seasonally, the pollution level is typically higher during the heating season from November to the following March. The interaction between pollution sources change and implementation of air pollution control measures was the main driving factor that caused the variation in air quality. Changes of industrial structure and improved energy effciency, the use of clean energy and preferred use of clean coal, reduction in pollution sources, and implementation of advanced environmental standards have all contributed to the reduction in air pollution, particularly since 1998.展开更多
Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance.However,the utility of these technological advancements remain dependent on the quality of bow...Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance.However,the utility of these technological advancements remain dependent on the quality of bowel preparation during colonoscopy.Poor bowel preparation has been shown to be associated with lower quality indicators of colonoscopy performance,such as reduced cecal intubation rates,increased patient discomfort and lower adenoma detection.The most popular bowel preparation regimes currently used are based on either Polyethylene glycol-electrolyte,a non-absorbable solution,or aqueous sodium phosphate,a lowvolume hyperosmotic solution.Statements from various international societies and several reviews have suggested that the efficacy of bowel preparation regimes based on both purgatives are similar,although patients' compliance with these regimes may differ somewhat.Many studies have now shown that factors other than the type of bowel preparation regime used,can influence the quality of bowel preparation among adult patients undergoing colonoscopy.These factors can be broadly categorized as either patient-related or procedure-related.Studies from both Asia and the West have identified patient-related factors such as an increased age,male gender,presence of co-morbidity and socioeconomic status of patients to be associated with poor bowel preparation among adults undergoing routine out-patient colonoscopy.Additionally,procedure-related factors such as adherence to bowel preparation instructions,timing of bowel purgative administration and appointment waiting times for colonoscopy are recognized to influence the quality of colon cleansing.Knowledge of these factors should aid clinicians in modifying bowel preparation regimes accordingly,such that the quality of colonoscopy performance and delivery of service to patients can be optimised.展开更多
China has the largest apple planting area and total yield in the world, and the Fuji apple is the major cultivar, accounting for more than 70％ of apple planting acreage in China. Apple qualities are affected by meteo...China has the largest apple planting area and total yield in the world, and the Fuji apple is the major cultivar, accounting for more than 70％ of apple planting acreage in China. Apple qualities are affected by meteorological conditions, soil types, nutrient content of soil, and management practices. Meteorological factors, such as light, temperature and moisture are key environmental conditions affecting apple quality that are difficult to regulate and control. This study was performed to determine the effect of meteorological factors on the qualities of Fuji apple and to provide evidence for a reasonable regional layout and planting of Fuji apple in China. Fruit samples of Fuji apple and meteorological data were investigated from 153 commercial Fuji apple orchards located in 51 counties of 11 regions in China from 2010 to 2011. Partial least-squares regression and linear programming were used to analyze the effect model and impact weight of meteorological factors on fruit quality, to determine the major meteorological factors influencing fruit quality attributes, and to establish a regression equation to optimize meteorological factors for high-quality Fuji apples. Results showed relationships between fruit quality attributes and meteorological factors among the various apple producing counties in China. The mean, minimum, and maximum temperatures from April to October had the highest positive effects on fruit qualities in model effect loadings and weights, followed by the mean annual temperature and the sunshine percentage, the temperature difference between day and night, and the total precipitation for the same period. In contrast, annual total precipitation and relative humidity from April to October had negative effects on fruit quality. The meteorological factors exhibited distinct effects on the different fruit quality attributes. Soluble solid content was affected from the high to the low row preface by annual total precipitation, the minimum temperature from April to October, the mean temperature from April to October, the temperature difference between day and night, and the mean annual temperature. The regression equation showed that the optimum meteorological factors on fruit quality were the mean annual temperature of 5.5-18°C and the annual total precipitation of 602-1121 mm for the whole year, and the mean temperature of 13.3-19.6°C, the minimum temperature of 7.8-18.5°C, the maximum temperature of 19.5°C, the temperature difference of 13.7°C between day and night, the total precipitation of 227 mm, the relative humidity of 57.5-84.0％, and the sunshine percentage of 36.5-70.0％ during the growing period （from April to October）.展开更多
Mechanical Quality factor（Q factor） of the resonator is an important parameter for the cylinder vibratory gyroscope（CVG）. Traditional analytical methods mainly focus on a partial energy loss during the vibration p...Mechanical Quality factor（Q factor） of the resonator is an important parameter for the cylinder vibratory gyroscope（CVG）. Traditional analytical methods mainly focus on a partial energy loss during the vibration process of the CVG resonator, thus are not accurate for the mechanical Q factor prediction. Therefore an integrated model including air damping loss, surface defect loss, support loss, thermoelastic damping loss and internal friction loss is proposed to obtain the mechanical Q factor of the CVG resonator. Based on structural dynamics and energy dissipation analysis, the contribution of each energy loss to the total mechanical Q factor is quantificationally analyzed. For the resonator with radius ranging from 10 mm to 20 mm, its mechanical Q factor is mainly related to the support loss, thermoelastic damping loss and internal friction loss, which are fundamentally determined by the geometric sizes and material properties of the resonator. In addition, resonators made of alloy 3J53 （Ni42CrTiA1）, with different sizes, were experimentally fabricated to test the mechanical Q factor. The theoretical model is well verified by the experimental data, thus provides an effective theoretical method to design and predict the mechanical Q factor of the CVG resonator.展开更多
In order to solve the problem that the quality factor （ Q factor） of the conventional defected ground structure （DGS）is not high and cannot produce a sharp resonant band, a novel S-slot DGS is presented. Compared ...In order to solve the problem that the quality factor （ Q factor） of the conventional defected ground structure （DGS）is not high and cannot produce a sharp resonant band, a novel S-slot DGS is presented. Compared with the conventional DGS, the proposed S-slot DGS has a much higher Q factor, a quite simpler layout and a steeper band rejection. Its equivalent circuit model is extracted by analyzing the transfer characteristics, and design parameters are calculated according to the deducted equations. Characteristics of this type of DGS are investigated with variable dimension parameters and an experiential method for the design of the S-slot DGS is summarized. Finally, a sample of a compact S-slot DGS unit resonated at 4. 64 GHz is fabricated. Its Q factor is as high as 39. 66 and its size is only 5.00 mm × 1.40 mm, with a steep resonant band and a low insertion-loss passband. The measured results show a good agreement with simulation, which demonstrates the applicability of the S-slot DGS in practical engineering.展开更多
In the analysis of how environmental regulation affects the comparative advantage of trade,existing literature ignores industry's inherent heterogeneity, which draws remarkably different conclusions. In view of th...In the analysis of how environmental regulation affects the comparative advantage of trade,existing literature ignores industry's inherent heterogeneity, which draws remarkably different conclusions. In view of this, the paper analyzed the mechanism of environmental regulation on the export quality of different industries from the perspective of factor input structure heterogeneity. Based on the panel data of China's manufacturing industry, the paper used the system generalized method of moments method to examine the heterogeneity influence of environmental regulation on manufacturing export quality. The study found that, first, environmental regulation affected the export quality upgrade of the manufacturing sector through offset effect and compensation effect, and the direction of the impact would mainly depend on the industry's factor input structure. Second, for industries with larger fixed-asset investment(FAI) ratio in the factor input structure, the current environmental regulation policy was not conducive to the export quality upgrading of the industries. However, there was a significant U-shaped dynamic relationship between them. As environmental regulations became stricter, when regulatory stringency went beyond the inflection point, the policy would promote the upgrading of export quality. But for industries with smaller proportion of FAI, environmental regulation exerted a favorable impact on the export quality upgrade, following a J-shaped marginal growth curve.Third, for industries with different factor input structure, their export quality had been effectively upgraded as expected by factors like human capital investment, independent R&D, technology introduction, and foreign direct investment; but raising per capita capital stock and expanding enterprise size did not produce significant direct impact on export quality upgrade. These conclusions remained robust after using different measurement methods and replacing with other variables. Therefore, this paper suggests that governments should take industry heterogeneity into consideration and formulate differentiated hierarchical environmental policies.Besides, they should strengthen the enforcement of the current environmental regulation policies. By doing so, enterprises are forced to improve their technology and product quality so that they can better cope with rising compliance costs, eliminate backward industries, and resolve excess capacity. In this way, the economic structure would be transformed and upgraded from the supply side.展开更多
In order to investigate the effect of meteorological factors on the yield and quality of special rice during the filling stage, an experiment was conducted with 10 special rice varieties which were planted in three di...In order to investigate the effect of meteorological factors on the yield and quality of special rice during the filling stage, an experiment was conducted with 10 special rice varieties which were planted in three different regions during spring 2017. The results showed that the quality traits and yields from different regions of the same variety were different, which reached up to a significant level in most varieties. Among the quality traits, the grain chalkiness rate and chalkiness degree were the most sensitive to different climatic factors, and changes were found among them in different regions, while minor variation was found between brown rice rate and white rice rate. The parameters that were severely affected by temperature were gel consistency, gelatinization temperature, brown rice rate and yield during the filling stage. The critically affected factors by heat were brown rice rate, protein content, essential amino acid and amylose content while brown rice rate, chalkiness rate and gelatinization temperature were substantially affected by water factors. Grain yield and quality were closely related to meteorological factors on different stages after heading. Our results revealed that yield and quality of special rice were significantly influenced by meteorological factors during the grain filling stage.展开更多
文摘BACKGROUND Patients with middle and advanced hepatocellular carcinoma(HCC)frequently experience significant anxiety and depression,severely affecting their quality of life.AIM To examine the anxiety and depression status of patients with middle and advanced HCC,the influencing factors,and the correlation between these psychological factors and quality of life.METHODS We collected baseline data from 100 patients with HCC,assessing anxiety and depression levels using the Hamilton Anxiety Rating Scale(HAMA)and Hamilton Depression Rating Scale(HAMD).Quality of life was evaluated with the Functional Assessment of Cancer Therapy-Hepatobiliary Questionnaire.Multivariate logistic regression analyzed clinical and psychosocial factors affecting anxiety and depression,while Pearson correlation assessed relationships among HAMA,HAMD,and Functional Assessment of Cancer Therapy-Hepatobiliary Questionnaire scores.RESULTS Results indicated that 64%of patients exhibited anxiety and 65%showed depression symptoms.Key influencing factors included Barcelona Clinic Liver Cancer C stage,multiple tumors,social support,prior treatments(such as liver resection and transcatheter arterial chemoembolization/hepatic artery infusion chemotherapy),as well as HAMA and HAMD scores.Anxiety and depression correlated negatively with quality of life,with coefficients of-0.671 and-0.575 for HAMA and HAMD,respectively.CONCLUSION Anxiety and depression are prevalent among patients with middle and advanced HCC,impacting quality of life.This underscores the need for psychological health considerations in liver cancer treatment and establishing psychological interventions is essential.
基金supported by the National Natural Science Foundation of China(Grant No.52175552)the National Key RD Program of China(Grant Nos.2022YFB3205400 and 2022YFB3204300).
文摘Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision,and the anisotropic nature of silicon is frequently overlooked.To address these issues,this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs.The optimized square-lattice PnC slabs,featuring a rounded-cross structure oriented along the`110e directions of silicon,achieve an impressive relative bandgap(RBG)width of 82.2%for in-plane modes.When further tilted by 15° from the (100) directions within the(001)plane,the optimal RBG width is expanded to 91.4%.We fabricate and characterize thin-film piezoelectric-on-silicon LVRs,with or without optimized 2D PnC slabs.The presence of PnC slabs around anchors increases the series and parallel quality factors Q_(s) and Q_(p) from 2240 to 7118 and from 2237 to 7501,respectively,with the PnC slabs oriented along the`110e directions of silicon.
基金supported by Zhangjiang Laboratory,the SHINE R&D project(No.2017SHZDZX02)the SHINE projectthe National Natural Science Foundation of China(No.12125508).
文摘We report the world-leading performance of a 1.3 GHz cryomodule equipped with eight 9-cell superconducting radio-frequency cavities that underwent a medium-temperature furnace baking process.During continuous wave horizontal testing,these cavities achieved unprecedented average intrinsic quality factors of 4.0×10^(10)at 20 MV/m and 3.2×10^(10)at 29 MV/m,with no instances of field emission.The cryomodule demonstrates near-complete preservation of ultra-high quality factors and ultra-high accelerating gradients from vertical to horizontal testing,marking a significant milestone in continuous-wave superconducting radio-frequency accelerator technology.This letter presents the cryomodule development experience,includ-ing cavity preparation,cryomodule assembly,degaussing,fast cooldown,and performance testing.
基金supported by the National Key Research and Development Program of China(No.2022YFC2903902)the National Natural Science Foundation of China(Nos.52204080and 52174070)the Fundamental Research Funds for the Central Universities of China(No.2023GFYD17)。
文摘Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.
基金supported by the National Natural Science Foundation of China(Grant Nos.12225203,11622215,and 11872111)the 111 Project(Grant No.B16003).
文摘Damped acoustic systems have a limited quality factor due to intrinsic loss.By introducing gain elements,a method to enhance the quality factor of damped systems is proposed based on the concept of bound states in the continuum(BICs).The acoustic model under study is a two-port waveguide system installed with two side Helmholtz resonators connected by a coupling tube.Based on the temporal coupled-mode theory,a Hamiltonian matrix with both intrinsic and radiation losses is used to characterize the resonance behavior of the coupled resonators.To achieve a high quality factor,acoustic gain is introduced to compensate the intrinsic loss,leading the Hamiltonian parameters toward a quasi-BIC condition.Numerical simulation demonstrates a gain-assisted and quasi-BIC-supported extremely high quality factor in damped acoustic systems.The concept is further utilized to design a sensor model for particle size detection.The enhanced sensing performance due to high quality factors is numerically demonstrated.The findings suggest potential applications in acoustic sensing and detection devices.
基金National Key Research and Development Program of China(No.2022YFC3204404,2023YFF1303705)National Natural Science Foundation of China(No.U2243206)。
文摘The Yangtze River economic belt(YREB),China is important to the Chinese economy and for supporting sustainable development.Clarifying the relationship between water quality indices and socioeconomic indicators could help improve aquatic environment management in the YREB and our understanding of the causes and effects of water quality variations in other large river basins.In this study,river water quality,factors affecting water quality,and management strategies,and correlations between water quality indices and socioeconomic indicators in the YREB during the 13th Five-Year Plan period(2016-2020)were assessed.The single-factor evaluation method,constant price for GDP,and correlation analyses were adopted.The results showed that:1)water quality in the YREB improved during the 13th Five-Year Plan period.The number of aquatic environment sections meeting GradeⅠ-Ⅲwater quality standards increased by 13.1%and the number below Grade V decreased by 2.9%.2)The values of 12 indicators in the YREB exceeded relevant standards.The indicators with highest concentreation were the total phosphorus,chemical oxygen demand,ammonia nitrogen,and permanganate index,which were relatively high in downstream regions in Anhui Province,Jiangsu Province,and Shanghai Municipality.3)Ammonia nitrogen,chemical oxygen demand,and total phosphorus emissions per unit area and water extraction per unit area are relatively high in the three downstream regions mentioned above.4)Increased domestic sewage discharges have increased total wastewater discharges in the YREB.5)River water quality in the YREB strongly correlated with population,economic,and water resource indices and less strongly correlated with government investment,agriculture,meteorology,energy,and forestry indices.This confirmed the need to decrease wastewater discharges and non-point-source pollutant emissions.The aquatic environment could be improved by taking reasonable measures to control population growth,adjusting the industrial structure to accelerate industrial transformation and increase the proportion of tertiary industries,and investing in technological innovations to protect the environment.
基金supported by the National Natural Science Foundation of China(Grant Nos.11874270 and 12174228)the Shenzhen Basic Research Special Project(Grant No.JCYJ20240813141606009)。
文摘A theory based on the superposition principle is developed to uncover the basic physics of wave behavior in a finite grating of N unit cells.The theory reveals that bound states in the continuum(BICs)of infinite quality factor(Q-factor)can be supported by such a grating when perfect reflection is introduced at its boundaries.If geometrical perturbations are introduced into the structure,the dark BICs transform into bright quasi-BICs with finite Q-factor,maintaining spectral characteristics nearly identical to those of quasi-BICs supported by infinite gratings.When the boundaries are replaced with high-reflectivity metallic mirrors,the Q-factor of the resonant mode is reduced to be finite;however,it can be much larger than that in the corresponding nanostructure with open boundaries and can be tuned over a large range by varying the number of unit cells or boundary conditions.
基金Supported by Earmarked Fund for Modern Rapeseed Research System of China(nycytx-00563)Program of Guizhou Academy of Agricultural Sciences[ZX(2007)015+2 种基金(2009)030]Program of Agriculture Department of Guizhou Province[(2009)007]Program of Science and Technology Department of Guizhou Province[(2010)3087]~~
文摘[Objective] This study aimed to analyze the influence of five cultivation factors including sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount and potash fertilizer amount on the quality parameters of Brassica napus hybrid＆ [Method] Statistical analysis on the data from previous studies and our work was carried out [Result] The contents of erucic acid, thioglycoside, oil, oleic acid and linoleic acid were negatively correlated with the sowing date, while the contents of seed protein, palmitic acid, stearic acid and linolenic acid were positively correlated with the sowing date. The total amount of fat and protein, the ratio of unsaturated fatty acid （UFA） to saturated fatty acid （SFA）, the fatty acid （FA） of erucic acid chain, the total amount of oleic acid and linoleic acid were negatively correlated with the sowing date; the UFA content, the unsatu- ration index, the SFA content, the 18-C FA content, and the ratio of UFA to FA in erucic acid chain were positively correlated with the sowing date. The contents of erucic acid, thioglycoside, seed protein, oleic acid, linolenic acid and eicosenoic acid were negatively correlated with the plant density, while the contents of oil, palmitic acid, stearic acid and linoleic acid were positively correlated with the plant density. The total amount of fat and protein （F ＆ P）, and the ratio of UFA to FA in erucic acid chain were negatively correlated with the plant density, while the UFA content, the unsaturation index, the SFA content, the ratio of UFA to SFA, the 18-C FA content, the FA in erucic acid chain, and the total amount of oleic acid and linoleic acid were positively correlated with the plant density. The contents of erucic acid, thioglycoside, oil, protein in milled rapeseed, palmitic acid and eicosenoic acid were negatively correlated with the nitrogen fertilizer amount, while the contents of seed protein, oleic acid, stearic acid, linoleic acid and linolenic acid were posi- tively correlated with the nitrogen fertilizer amount; the total F ＆ P, the unsaturation index and the ratio of UFA to FA in erucic acid chain were positively correlated with the nitrogen fertilizer amount, while the UFA content, the SFA content, the FA in erucic acid chain, the total amount of oleic acid and linoleic acid, the ratio of UFA to SFA, and the 18-C FA content were negatively correlated with the nitrogen fertilizer amount The contents of erucic acid, thioglycoside, seed protein, linoleic acid and linolenic acid were negatively correlated with the potash fertilizer amount, while contents of oil, oleic acid, stearic acid and eicosenoic acid were positively correlated with the potash fertilizer amount; the total F ＆ P, the unsaturation index, the SFA, and the ratio of UFA to FA in erucic acid chain were negatively correlated with the potash fertilizer amount There were negative correlations between the contents of erucic acid, thioglycoside, seed protein, palmitic acid, stearic acid, linoleic acid, linolenic acid and phosphate fertilizer amount; positive correlations between the contents of oil, oleic acid, eicosenoic acid and phosphate fertilizer amount The total UFA, the unsaturation index, the 1843 FA, the SFA, the FA in erucic acid chain, and the ratio of UFA to FA in erucic acid chain were negatively correlated with the phosphate fertilizer amount [Conclusion] This study identified the correlations of the five cultivation factors with the quality parameters of high-quality Brassica napus hybrids, to provide theoretical basis for its cultivation.
基金Supported by Earmarked Fund for Modern Rapeseed Research System of China(nycytx-00563)High-oil Hybrid Brassica napus Rapeseed Cultivation Technology Research Program of Guizhou Academy of Agricultural Sciences[ZX(2007)015]+3 种基金New High-yield Rapeseed Cultivar Yoyan 599 Cultivation and Promotion Program of Agriculture Department of Guizhou Province[(2009)007]Hybrid Rapeseed Cultivar Youyan 599 Promotion Program of Guizhou Academy of Agricultural Sciences[(2009)030]New High-oil Rapeseed Cultivar Sanbei 98 Cultivation and Promotion Program of Agriculture Department of Guizhou Province[(2010)3087]Earmarked Fund for Modern Rapeseed Research System of Guizhou Province(GZCYTX2013-0802)~~
文摘[Objective] This study aimed to analyze the influence of five cultivation factors： sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount and potash fertilizer amount on oil quality and stability of Brassica napus hybrids. [Method] Statistical analysis was carried out based on the data from previous studies and our work. [Result] Sowing date had no significant influence on oil quality and stability of B. napus hybrids. The plant density shared a positive correlation with 18-C fatty acid （FA） content, unsaturated fatty acid （UFA） content, total content of linoleic acid and linolenic acid, index of unsaturated fatty acid （IUFA）, so a large plant density can improve the oil quality （by increasing18-C FA content, UFA content, total content of linoleic acid and linolenic acid）, but reduce the oil stability （by increasing IUFA）. The amount of nitrogen fertilizer had no significant influence on the contents of 18-C FA and UFA, but significant positive correlations with the total content of linoleic acid and linolenic acid and IUFA. So, the total content of linoleic acid and linolenic acid can be reduced by increasing nitrogen amount, meanwhile the oil stability was also decreased. Phosphate fertilizer amount did not affect 18-C FA significantly, but was negatively correlated with the UFA content, total content of linoleic acid and linolenic acid, and IUFA. So, increasing the amount of applied phosphate fertilizer can reduce UFA content, total content of linoleic acid and linolenic acid, thereby improving oil stability. Potash fertilizer had no significant influence on the IUFA, a significant positive correlation with 18-C FA content, an insignificant positive correlation with the the UFA content, and a negative correlation with the total content of linoleic acid and linolenic acid. The oil content of rapeseed shared an extremely significant positive correlation with 18-C FA content and UFA content, an negative correlation with the total content of linoleic acid and linolenic acid, and no significant correlation with IUFA. [Conclusion] This study identified the effects of five main cultivation factors on oil quality and stability of B. napus hybrids, and the correlations of oil content with 18-C FA content, UFA content, total content of linoleic acid and linolenic acid, and IUFA.
文摘Human factors engineering and quality management are different research branches in the field of industrial engineering.A basis for interaction based on the concepts and techniques of human factors engineering and quality management with some practical examples of cooperative effect is defined in this paper.The specific challenges about the quality management in manufacturing and service are presented to demonstrate that the human factors analysis of quality problems leads to new tends for integrated development.
文摘The mode frequencies and the quality factors for the equilateral triangular resonator (ETR), the square resonator (SR) and the rhombus resonator (RR) are numerically calculated by the finite difference time domain technique and the Padé approximation. The numerical results show that the resonant modes confined in an equilateral triangular cavity have much higher quality factors than those in the square or the rhombus cavities. The modes in the ETR are totally confined in transverse direction while those in the SR and RR are only partly confined. For the ETR with the side length of 4μm and the refractive index of 3 2, the mode quality factor of about 5 5×10 3 at the wavelength of 1 55μm has been obtained.
基金This work is supported by the National Natural Science Foundation of China （No. 41140033）.
文摘To facilitate investigation of the effect of imperfect elastic dissipation on the propagation of Rayleigh-type channel waves and use of their quality factors in investigations of the properties of coal seams, a simple method for calculating the quality factor QR is proposed in this paper. Introduction of complex velocities into the dispersion function allows calculation of the dispersion function of Rayleigh-type channel waves in coal seams. By the control variable method, we analyzed changes in QR with changes in coal seam thickness and P- and S-wave Q-factors within the coal seam and adjacent rock layers. The numerical results show that the trend of the QR curve is consistent with the group velocity curve. The minimum QR value occurs at the Airy phase frequency; the Airy phase frequency decreases as coal seam thickness increases. The value of QR increases with increasing QS2(quality factor for S wave in coal seam). We can compensate for the absorption of Rayleigh-type channel waves using the computed QR curve. Inversion of the QR curve can also be used to predict the thicknesses and lithologies of coal seams.
基金supported by the Major Project of the Ministry of Science and Technology of China(No.2011ZX05024-001-01)National Nature Science Foundation of China(No.41140033)
文摘The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extraction method based on the energy ratio before and after the wavelet attenuation, named the energy-ratio method（ERM）. The proposed method uses multipoint signal data in the time domain to estimate the wavelet energy without invoking the source wavelet spectrum, which is necessary in conventional Q extraction methods, and is applicable to any source wavelet spectrum; however, it requires high-precision seismic data. Forward zero-offset VSP modeling suggests that the ERM can be used for reliable Q inversion after nonintrinsic attenuation（geometric dispersion, refl ection, and transmission loss） compensation. The application to real zero-offset VSP data shows that the Q values extracted by the ERM and spectral ratio methods are identical, which proves the reliability of the new method.
基金supported by the State Key Program of National Natural Science Foundation of China (No.41030744)the Specialized Research Fund of State Key Laboratory of Urban and Regional Ecology
文摘The rapid development in Beijing, the capital of China, has resulted in serious air pollution problems. Meanwhile great efforts have been made to improve the air quality, especially since 1998. The variation in air quality under the interaction of pollution and control in this mega city has attracted much attention. We analyzed the changes in ambient air quality in Beijing since the 1980’s using the Daniel trend test based on data from long-term monitoring stations. The results showed that different pollutants displayed three trends： a decreasing trend, an increasing trend and a flat trend. SO2, dustfall, B[a]P, NO2 and PM10 fit decreasing trend pattern, while NOx showed an increasing trend, and CO, ozone pollution, total suspended particulate （TSP）, as well as Pb fit the flat trend. The cause of the general air pollution in Beijing has changed from being predominantly related to coal burning to mixed traffic exhaust and coal burning related pollution. Seasonally, the pollution level is typically higher during the heating season from November to the following March. The interaction between pollution sources change and implementation of air pollution control measures was the main driving factor that caused the variation in air quality. Changes of industrial structure and improved energy effciency, the use of clean energy and preferred use of clean coal, reduction in pollution sources, and implementation of advanced environmental standards have all contributed to the reduction in air pollution, particularly since 1998.
文摘Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance.However,the utility of these technological advancements remain dependent on the quality of bowel preparation during colonoscopy.Poor bowel preparation has been shown to be associated with lower quality indicators of colonoscopy performance,such as reduced cecal intubation rates,increased patient discomfort and lower adenoma detection.The most popular bowel preparation regimes currently used are based on either Polyethylene glycol-electrolyte,a non-absorbable solution,or aqueous sodium phosphate,a lowvolume hyperosmotic solution.Statements from various international societies and several reviews have suggested that the efficacy of bowel preparation regimes based on both purgatives are similar,although patients' compliance with these regimes may differ somewhat.Many studies have now shown that factors other than the type of bowel preparation regime used,can influence the quality of bowel preparation among adult patients undergoing colonoscopy.These factors can be broadly categorized as either patient-related or procedure-related.Studies from both Asia and the West have identified patient-related factors such as an increased age,male gender,presence of co-morbidity and socioeconomic status of patients to be associated with poor bowel preparation among adults undergoing routine out-patient colonoscopy.Additionally,procedure-related factors such as adherence to bowel preparation instructions,timing of bowel purgative administration and appointment waiting times for colonoscopy are recognized to influence the quality of colon cleansing.Knowledge of these factors should aid clinicians in modifying bowel preparation regimes accordingly,such that the quality of colonoscopy performance and delivery of service to patients can be optimised.
基金supported by the Forest Scientific Research in the Public Interest,China(201404720)the earmarked fund for the China Agriculture Research System(CARS-27)the Beijing Municipal Education Commission,China(CEFF-PXM2017_014207_000043)
文摘China has the largest apple planting area and total yield in the world, and the Fuji apple is the major cultivar, accounting for more than 70％ of apple planting acreage in China. Apple qualities are affected by meteorological conditions, soil types, nutrient content of soil, and management practices. Meteorological factors, such as light, temperature and moisture are key environmental conditions affecting apple quality that are difficult to regulate and control. This study was performed to determine the effect of meteorological factors on the qualities of Fuji apple and to provide evidence for a reasonable regional layout and planting of Fuji apple in China. Fruit samples of Fuji apple and meteorological data were investigated from 153 commercial Fuji apple orchards located in 51 counties of 11 regions in China from 2010 to 2011. Partial least-squares regression and linear programming were used to analyze the effect model and impact weight of meteorological factors on fruit quality, to determine the major meteorological factors influencing fruit quality attributes, and to establish a regression equation to optimize meteorological factors for high-quality Fuji apples. Results showed relationships between fruit quality attributes and meteorological factors among the various apple producing counties in China. The mean, minimum, and maximum temperatures from April to October had the highest positive effects on fruit qualities in model effect loadings and weights, followed by the mean annual temperature and the sunshine percentage, the temperature difference between day and night, and the total precipitation for the same period. In contrast, annual total precipitation and relative humidity from April to October had negative effects on fruit quality. The meteorological factors exhibited distinct effects on the different fruit quality attributes. Soluble solid content was affected from the high to the low row preface by annual total precipitation, the minimum temperature from April to October, the mean temperature from April to October, the temperature difference between day and night, and the mean annual temperature. The regression equation showed that the optimum meteorological factors on fruit quality were the mean annual temperature of 5.5-18°C and the annual total precipitation of 602-1121 mm for the whole year, and the mean temperature of 13.3-19.6°C, the minimum temperature of 7.8-18.5°C, the maximum temperature of 19.5°C, the temperature difference of 13.7°C between day and night, the total precipitation of 227 mm, the relative humidity of 57.5-84.0％, and the sunshine percentage of 36.5-70.0％ during the growing period （from April to October）.
基金Supported by National Natural Science Foundation of China(Grant Nos.51335011,51505489)
文摘Mechanical Quality factor（Q factor） of the resonator is an important parameter for the cylinder vibratory gyroscope（CVG）. Traditional analytical methods mainly focus on a partial energy loss during the vibration process of the CVG resonator, thus are not accurate for the mechanical Q factor prediction. Therefore an integrated model including air damping loss, surface defect loss, support loss, thermoelastic damping loss and internal friction loss is proposed to obtain the mechanical Q factor of the CVG resonator. Based on structural dynamics and energy dissipation analysis, the contribution of each energy loss to the total mechanical Q factor is quantificationally analyzed. For the resonator with radius ranging from 10 mm to 20 mm, its mechanical Q factor is mainly related to the support loss, thermoelastic damping loss and internal friction loss, which are fundamentally determined by the geometric sizes and material properties of the resonator. In addition, resonators made of alloy 3J53 （Ni42CrTiA1）, with different sizes, were experimentally fabricated to test the mechanical Q factor. The theoretical model is well verified by the experimental data, thus provides an effective theoretical method to design and predict the mechanical Q factor of the CVG resonator.
基金The National Natural Science Foundation of China(No60890071)the National High Technology Research and Development Program of China(863Program)(No2009AA01Z132)
文摘In order to solve the problem that the quality factor （ Q factor） of the conventional defected ground structure （DGS）is not high and cannot produce a sharp resonant band, a novel S-slot DGS is presented. Compared with the conventional DGS, the proposed S-slot DGS has a much higher Q factor, a quite simpler layout and a steeper band rejection. Its equivalent circuit model is extracted by analyzing the transfer characteristics, and design parameters are calculated according to the deducted equations. Characteristics of this type of DGS are investigated with variable dimension parameters and an experiential method for the design of the S-slot DGS is summarized. Finally, a sample of a compact S-slot DGS unit resonated at 4. 64 GHz is fabricated. Its Q factor is as high as 39. 66 and its size is only 5.00 mm × 1.40 mm, with a steep resonant band and a low insertion-loss passband. The measured results show a good agreement with simulation, which demonstrates the applicability of the S-slot DGS in practical engineering.
文摘In the analysis of how environmental regulation affects the comparative advantage of trade,existing literature ignores industry's inherent heterogeneity, which draws remarkably different conclusions. In view of this, the paper analyzed the mechanism of environmental regulation on the export quality of different industries from the perspective of factor input structure heterogeneity. Based on the panel data of China's manufacturing industry, the paper used the system generalized method of moments method to examine the heterogeneity influence of environmental regulation on manufacturing export quality. The study found that, first, environmental regulation affected the export quality upgrade of the manufacturing sector through offset effect and compensation effect, and the direction of the impact would mainly depend on the industry's factor input structure. Second, for industries with larger fixed-asset investment(FAI) ratio in the factor input structure, the current environmental regulation policy was not conducive to the export quality upgrading of the industries. However, there was a significant U-shaped dynamic relationship between them. As environmental regulations became stricter, when regulatory stringency went beyond the inflection point, the policy would promote the upgrading of export quality. But for industries with smaller proportion of FAI, environmental regulation exerted a favorable impact on the export quality upgrade, following a J-shaped marginal growth curve.Third, for industries with different factor input structure, their export quality had been effectively upgraded as expected by factors like human capital investment, independent R&D, technology introduction, and foreign direct investment; but raising per capita capital stock and expanding enterprise size did not produce significant direct impact on export quality upgrade. These conclusions remained robust after using different measurement methods and replacing with other variables. Therefore, this paper suggests that governments should take industry heterogeneity into consideration and formulate differentiated hierarchical environmental policies.Besides, they should strengthen the enforcement of the current environmental regulation policies. By doing so, enterprises are forced to improve their technology and product quality so that they can better cope with rising compliance costs, eliminate backward industries, and resolve excess capacity. In this way, the economic structure would be transformed and upgraded from the supply side.
文摘In order to investigate the effect of meteorological factors on the yield and quality of special rice during the filling stage, an experiment was conducted with 10 special rice varieties which were planted in three different regions during spring 2017. The results showed that the quality traits and yields from different regions of the same variety were different, which reached up to a significant level in most varieties. Among the quality traits, the grain chalkiness rate and chalkiness degree were the most sensitive to different climatic factors, and changes were found among them in different regions, while minor variation was found between brown rice rate and white rice rate. The parameters that were severely affected by temperature were gel consistency, gelatinization temperature, brown rice rate and yield during the filling stage. The critically affected factors by heat were brown rice rate, protein content, essential amino acid and amylose content while brown rice rate, chalkiness rate and gelatinization temperature were substantially affected by water factors. Grain yield and quality were closely related to meteorological factors on different stages after heading. Our results revealed that yield and quality of special rice were significantly influenced by meteorological factors during the grain filling stage.
