While bagged flat peaches gain increasing consumer preference,the bagging process inhibits anthocyanin production and fruit coloration in most peach cultivars.Certain peach cultivars,including the rapidly expanding‘Z...While bagged flat peaches gain increasing consumer preference,the bagging process inhibits anthocyanin production and fruit coloration in most peach cultivars.Certain peach cultivars,including the rapidly expanding‘Zhongyoupan 9’,demonstrate a light-independent anthocyanin biosynthesis pattern and accumulate anthocyanins under artificial darkness.The underlying molecular mechanisms,however,remain unelucidated.This study examined two flat peach varieties:‘Zhongpan 17’,exhibiting light-dependent anthocyanin biosynthesis,and‘Zhongyoupan 9’,displaying light-independent anthocyanin biosynthesis.The pericarp of‘Zhongyoupan 9’contained substantially higher anthocyanin levels compared to‘Zhongpan 17’.Metabolomic analysis identified the marked increase in anthocyanins,particularly cyanidin-3-O-glucoside,as the primary factor in‘Zhongyoupan 9’coloration under artificial darkness.Transcriptomic analyses revealed that PpHY5(long hypocotyl 5)showed upregulation in‘Zhongyoupan 9’but downregulation in‘Zhongpan 17’,with its expression pattern correlating positively with color changes in both varieties.The role of PpHY5 in positively regulating anthocyanin biosynthesis was confirmed through reduced anthocyanin levels in peach fruits treated with a PpHY5 virus-induced gene-silencing construct.These findings suggest that the PpHY5 regulates red color development in‘Zhongyoupan 9’under artificial darkness.展开更多
Considering the unique properties of small spacecraft, such as light weight, low power-consumption and high heat flux density, a new kind of lightweight boron carbide （B4C） radiation-protection coating material was ...Considering the unique properties of small spacecraft, such as light weight, low power-consumption and high heat flux density, a new kind of lightweight boron carbide （B4C） radiation-protection coating material was proposed. New techniques for preparing LSMO thermal control coating and B4C radiation-protection coating were developed. The sample piece of multi-functional structure was manufactured by using the proposed materials, and a series of performance tests, such as thermal control and radiation-protection behaviors were evaluated. Test results show that： the emissivity of the multi-functional structure varies from 0.42 to 0.86 at 240 K to 353 K and the phase transition temperature is about 260 K. The electron radiation-protection ability of the multi-functional structure is 3.3 times better than that of Al material. The performance index of this multi-functional structure can meet the requirements for space application in on-board electronic equipment.展开更多
[Objectives]The infection symptoms of cyst nematodes were found in Yuexi, Sichuan. In order to identify the pathogen, the isolated nematodes were identified by morphology and molecular biology. [Methods] The potato ro...[Objectives]The infection symptoms of cyst nematodes were found in Yuexi, Sichuan. In order to identify the pathogen, the isolated nematodes were identified by morphology and molecular biology. [Methods] The potato roots and soil around the roots were collected, the nematodes in the roots were stained and observed, and the cysts were separated by the simple floating method. The second-stage juveniles(J2 s), females and cysts were found, and they were photographed and morphologically measured. The DNA of cysts and J2 s were extracted and identified by species-specific PCR. The DNA sequences of 18 S gene, 28 S D2-D3 region and ITS region in ribosomal DNA were obtained. Sequences of some cyst nematode species were downloaded from GenBank for sequence alignment, and MrBayes 3.2.3 software was used to construct a Bayesian phylogenetic tree. [Results] The nematodes could invade hosts’ root system. The basal knobs of J2 s was nearly round and inclined backward;the average length of the stylet was shorter than 23 μm;the Granek ratio of cysts was greater than or equal to 3, which is highly consistent with that of Globodera rostochiensis. The DNA templates of three cysts and four J2 s were amplified by species-specific PCR, and a band of about 430 bp was obtained. After further sequencing, the length was 434 bp, which is consistent with G. rostochiensis. The evolutionary analysis of rDNA 18 S and 28 S showed that the cyst nematode population was a Globodera species, and further evolutionary analysis of ITS gene confirmed that the population was G. rostochiensis. [Conclusions] The nematodes are G. rostochiensis, which is a quarantine species of great concern to both domestic and import quarantine. Once introduced and colonized, it is hard to eradicate. It is necessary to establish a monitoring system as soon as possible, strengthen the quarantine, supervision and management, increase investment in G. rostochiensis research and development, and develop detection and control technologies, so as to escort the healthy and sustainable development of China’s potato industry.展开更多
Climate change and human activities have great implications for hydrological process and water projects planning. In order to evaluate the impacts on stream-flow, statistical methods and SWAT model are applied to this...Climate change and human activities have great implications for hydrological process and water projects planning. In order to evaluate the impacts on stream-flow, statistical methods and SWAT model are applied to this research. The results indicate that the abrupt change year (1965) of annual stream-flow is chosen as the split point of natural and human influenced (particularly reservoirs) periods. The calibrated SWAT model is proved to be applicable in this catchment and is used to simulate the monthly runoff which can be regarded as the natural runoff induced by climate change. A major finding of this study is that the reservoir regulations have apparently altered the monthly and seasonal stream-flow regimes. By quantifying the impacts of climate variation and human activities, the decreasing trend of annual stream-flow is found, and human activities are proved to be the dominant role in the catchment. This research improves our knowledge of hydrological responses to natural and artificial factors, and provides a better understanding for the future reservoir regulations.展开更多
Moderate exercise contributes to health, but excessive exercise may lead to physicalinjury or even endanger life. It is pressing for a device that can detect the intensity of exercise.Therefore, in order to enable rea...Moderate exercise contributes to health, but excessive exercise may lead to physicalinjury or even endanger life. It is pressing for a device that can detect the intensity of exercise.Therefore, in order to enable real-time detection of exercise intensity and mitigate the risks of harmfrom excessive exercise, a exercise intensity monitoring system based on the heart rate variability(HRV) from electrocardiogram (ECG) signal and linear features from phonocardiogram (PCG)signal is proposed. The main contributions include: First, accurate analysis of HRV is crucial forsubsequent exercise intensity detection. To enhance HRV analysis, we propose an R-peak detectorbased on encoder-decoder and temporal convolutional network (TCN). Experimental resultsdemonstrate that the proposed R-peak detector achieves an F1 score exceeding 0.99 on real high-intensity exercise ECG datasets. Second, an exercise fatigue monitoring system based on multi-signal feature fusion is proposed. Initially, utilizing the proposed R-peak detector for HRV extractionin exercise intensity detection,which outperforms traditional algorithms, with the system achieving a classification performance of 0.933 sensitivity, 0.802 specificity, and 0.960 accuracy. To further improve the system, we combine HRV with the linear features of PCG. Our exercise intensitydetection system achieves 90.2% specificity, 96.7% recall, and 98.1% accuracy in five-fold cross-validation.展开更多
Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical activity.As a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovas...Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical activity.As a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovascular information,and their data acquisition devices are quiteconvenient.In this study,a novel hybrid approach of fractional Fourier transform(FRFT)com-bined with linear and discrete wavelet transform(DWT)features extracted from PCG is proposedfor PCG multi-class classification.The proposed system enhances the fatigue detection performanceby combining optimized FRFT features with an effective aggregation of linear features and DWTfeatures.The FRFT technique is employed to convert the 1-D PCG signal into 2-D image which issent to a pre-trained convolutional neural network structure,called VGG-16.The features from theVGG-16 were concatenated with the linear and DWT features to form fused features.The fusedfeatures are sent to support vector machine(SVM)to distinguish six distinct fatigue levels.Experi-mental results demonstrate that the proposed fused features outperform other feature combinationssignificantly.展开更多
A novel Ti cored wire containing Ti B2,Al60 V40 and Ti6 Al4 V mixed powders was developed for wirefeed arc deposition of Ti B/Ti composite coating,to enhance the hardness and wear resistance of Ti alloy.Results showed...A novel Ti cored wire containing Ti B2,Al60 V40 and Ti6 Al4 V mixed powders was developed for wirefeed arc deposition of Ti B/Ti composite coating,to enhance the hardness and wear resistance of Ti alloy.Results showed that after experiencing several chemical reactions,the wire was melted in the arc zone and turned into nonuniform droplets composed of Ti-Al-V-B melt and undecomposed Ti B2 particles.With the increase of welding current,the detachment time of droplet shortened while the transfer frequency accelerated,accompanied by the improvement in coating surface quality.The spatial distribution of Ti B whiskers in coating was governed by welding current.A uniform distribution could be achieved as welding current was sufficient at the expense of elevated dilution ratio,while increasing wire feeding speed could compensate the dilution loss of Ti B whisker to some extent.The decomposition process of Ti B_(2)particles and the microstructure evolution mechanism of coating was discussed in detail.The optimum coating possessed uniform microstructure,relatively low dilution ratio,and high hardness(639.1 HV_(0.5))as compared with Ti6 Al4 V substrate(326 HV_(0.5)).Indentation morphology analysis verified the excellent performance was ascribed to the load-sharing strengthening of Ti B whiskers.This study provides a high-efficiency fabrication method for the ever-developing titanium matrix composites(TMCs)coating.展开更多
Using CHIP （Chinese Household Income Project Survey） data and the sample selection bias corrected wage function model, this paper estimated changes in wage structure in China by ownership types （SOEs, COEs, FEs, an...Using CHIP （Chinese Household Income Project Survey） data and the sample selection bias corrected wage function model, this paper estimated changes in wage structure in China by ownership types （SOEs, COEs, FEs, and PEs） in 1995 and 2007. The major conclusions are as follows. First, effects of education on wage levels in SOEs and FEs become greater, while education effects decrease in SOEs and PEs under economic transition periods; firm-specific human capital becomes more important in the wage determination mechanism along with market-oriented reforms in SOEs, PEs, and FEs; age effect decreases in SOEs and COEs, but it becomes greater in PEs and FEs. Second, there exist wage structure differences between sectors by wage distributions. For example, in 2007, in SOEs, education return rates are higher for the low-wage and middle-wage groups, and the effect is the highest at the 40th percentile. However in COEs and FEs, education return rates are higher for the high-wage groups, and the effect is the highest at the 70th percentile in COEs and at the 70th percentile in FEs. Tenure effects are greater in the middle-wage groups （40th-80th） in SOEs, COEs, and FEs, and age effects are greater in the low-wage groups （5th-30th） in SOEs, FEs, and PEs.展开更多
Drop weight impact tester was used to accurately measure the bending impact resistance of various parts of Phyllostachys edulis,commonly known as moso bamboo,with a growth cycle of 3–8 years.Cellulose crystallinity i...Drop weight impact tester was used to accurately measure the bending impact resistance of various parts of Phyllostachys edulis,commonly known as moso bamboo,with a growth cycle of 3–8 years.Cellulose crystallinity in the bottom(B),middle(M)and top(T)of bamboo at different ages was calculated using peak height analysis in X-ray diffraction.Heatmap of Spearman correlation analysis was used to represent the correlation between chemical composition and impact mechanics.The breaking load(BL),fracture energy(FE)and impact deflection(ID)of 3–8-year-old bamboo were found to be in the range of~670–2120 N,~5.17–15.55 J,and~3.60–~17.76 mm,respectively.As the growth period of bamboo rises,the cellulose crystallinity at the B and T decreases first and then increases,while that for the M increases first and then remains stable.Similarly,the bending impact performance of bamboo was found to become stable with its growth and age.The flexural impact and toughness of the 4-year-old bamboo base material were better than other specimens.The enhancement in the bending impact properties of bamboo at different growth periods was influenced by the lignin content,while the value of FE was mainly positively correlated with ash,cold and hot water extracts and benzyl alcohol content.However the content of holocellulose and pentosan,air-dry density and,base density negatively influenced the FE.With the change in the height of the bamboo,the correlation between its impact mechanical properties and chemical composition gradually decreased.This study provides data support and theoretical basis for the age-appropriate thinning and application of moso bamboo.展开更多
The magnetron sputtered La0.7Sr0.3MnO3 films were implanted with different doses (5 ′ 1015 ions×cm?2 and 5 ′ 1016 ions×cm-2) of Al ions at different negative pulsed voltages (30 kV and 50 kV) by plasma bas...The magnetron sputtered La0.7Sr0.3MnO3 films were implanted with different doses (5 ′ 1015 ions×cm?2 and 5 ′ 1016 ions×cm-2) of Al ions at different negative pulsed voltages (30 kV and 50 kV) by plasma based ion implantation and then annealed at 973 K for 1 h in air. The microstructure, surface morphologies, surface roughness, metal-insulator transition and room temperature emittance properties of the post-implantation annealed films were investigated and compared with those of the La0.7Sr0.3MnO3 film annealed at 973 K for 1 h in air. The results indicate that the post- implantation annealed films show single perovskite phase and obvious (100) preferred orientation growth. The Mn-O bond length, surface roughness and metal-insulator transition temperature (TMI) of the films can be effectively adjusted by changing implantation voltage or implantation dose of Al ions. However, the change of implantation parameters just has a small effect on room temperature emittance of the films. Compared with the annealed film, the post-implantation annealed films have shorter Mn-O bond length and lower room temperature emittance. The TMI of the films implanted at low voltage is lower than that of the annealed film, which mainly results from the degradation of oxidization during annealing process and the part displacement of Mn3+-O2+- Mn4+ double exchange channels by Al3+-O2?-Mn4+. The post-implanted annealed film implanted at 50 kV/5 ′ 1016 ions×cm-2 has a higher TMI than the annealed film, which is 247 K. The increase of TMI of the film implanted with high dose of Al ions at high voltage can be attributed to the improvement of microstructure.展开更多
Using the 2000, 2004, and 2006 CHNS longitudinal survey data and econometric methods （random-effect probit regression model and DID methods）, this study conducted an empirical analysis to estimate the impact of NCMS...Using the 2000, 2004, and 2006 CHNS longitudinal survey data and econometric methods （random-effect probit regression model and DID methods）, this study conducted an empirical analysis to estimate the impact of NCMS. The major conclusions are as follows. First, predisposing factors, enabling factors, health care need factors, and lifestyle factors affect health care utilization. Second, results using DID methods indicate that NCMS did not affect health care service utilization （outpatient and inpatient） of individuals when ill, but it might increase the possibility of getting a health examination. Third, there is no difference in health care service utilization （both outpatient and inpatient） between the NCMS enrollment group and the non-enrollment group in both working age group （15-59） and the elderly group （60 and over）. Therefore, it can be said that NCMS did not affect the health care utilization in both the group. However, NCMS positively affects disease prevention behavior （visiting the hospital to receive a health examination） in the working age group, but the effect did not appear in the elderly group.展开更多
Disposable plastic straws are small,lightweight,and non-degradable,making them rarely recycled and causing severe environmental pollution.However,the search for suitable alternatives,balanc-ing high performance with l...Disposable plastic straws are small,lightweight,and non-degradable,making them rarely recycled and causing severe environmental pollution.However,the search for suitable alternatives,balanc-ing high performance with low cost,poses a substantial challenge.Inspired by bamboo’s flexibility and toughness,this study proposed an innovative solution:a biodegradable drinking straw fab-ricated by winding ultra-thin bamboo slices.The specially prepared bamboo slices demonstrated high tensile strength,exceptional flexibility for bending,and the ability to withstand repeated torsion.To address natural issues of color-producing group migration and mold susceptibility,the bamboo slices underwent simultaneous soaking and ultrasonic treatment.The resulting bam-boo straws exhibited remarkable properties with compressive strength of 16.42-19.01 MPa and bending strength of 14.21-15.02 MPa,which matched or exceeded those of commercial paper straws and were significantly higher than those of polypropylene(PP)and polylactic acid(PLA)straws.When exposed to various beverages,bamboo straws retained their structural integrity,absorbed significantly less water than paper straws,and the wet strength was 4.36 times greater than that of paper straws.Moreover,bamboo drinking straws exhibited low production costs and garnered widespread consumer approval.The strategy for industrial-scale production of bamboo straws offers significant potential for replacing plastic straws.展开更多
Previous satellite observations have identified the appearance of“cloud trough”(or“cloud trench”),with cloud tops visually collapsed following airborne cloud seeding operation,demonstrating the effect of weather m...Previous satellite observations have identified the appearance of“cloud trough”(or“cloud trench”),with cloud tops visually collapsed following airborne cloud seeding operation,demonstrating the effect of weather modification.However,refined observations of troughed clouds and associated microphysical processes are still notably scarce,especially those obtained via in-situ aircraft measurements.In this study,variations in cloud microphysics associated with and without troughed clouds along an airborne stratiform cloud seeding path over central China on 15 December 2019 are analyzed and compared based on aircraft measurements,ground-based radar observations,and FY-4A satellite imagery.The results are as follows.(1)The troughed clouds were mainly formed to the northeast of the flight path and were observed only in some parts of the seeded stratiform clouds.The seeding tracks became visible starting from 60 min after seeding and persisted for approximately 3 h,covering a maximum width of 30–40 km in FY-4A imagery.Radar echo enhancements can be observed by a ground-based radar at some parts of the seeding tracks.(2)The troughed clouds were observed only when the ambient air temperature(T)was≤-7℃,a condition favoring high nucleation efficiency of silver iodide(Ag I)aerosols,whereas no cloud troughs formed at higher temperatures.(3)The troughed clouds with strong radar echoes(i.e.,large precipitation)corresponded to regions with high values(>0.1 g m^(-3))of supercooled water content after cloud seeding,which facilitated the growth of precipitation particles.(4)Within the troughed clouds,the cloud optical thickness and cloud top height decreased,while the effective radii of cloud particles increased by nearly 10μm.These results provide valuable guidance for optimizing cold cloud seeding conditions in artificial rainfall enhancement.Meanwhile,the presence of high supercooled water content,particularly the threshold of supercooled water content,is a critical factor for strong precipitation,which necessitates further studies.展开更多
Hexagonal tungsten trioxide (h-WO3)microspheres were synthesized by a hydrothermal method,with ammonium paratungstate and hydrochloric acid as the raw materials.The effects of the process parameters on the phase compo...Hexagonal tungsten trioxide (h-WO3)microspheres were synthesized by a hydrothermal method,with ammonium paratungstate and hydrochloric acid as the raw materials.The effects of the process parameters on the phase compositions and morphologies of the products were investigated.The results showed that the hydrothermal temperature and molar ratio of the raw materials were important for avoiding the formation of impurity phases,namely WO3.0.33H2Oand WO3.H2O.The pure-phase h-WO3microspheres had a specific surface area of 40.0m^2/g,and were assembled from nanorods.The microspheres were used to support Pd,and the obtained Pd/h-WO3catalyst showed excellent catalytic activity in the hydrogenation of styrene under mild conditions,with a turnover frequency 0f 3050h^-1.The catalyst was recycled five times without loss of activity,i.e.,the supported catalyst had good recyclability.展开更多
This paper investigates the causal relationship between the Urban and Rural Resident Basic Medical Insurance(URRBMI)reform and household consumption in urban China using data from the Chinese Household Income Project ...This paper investigates the causal relationship between the Urban and Rural Resident Basic Medical Insurance(URRBMI)reform and household consumption in urban China using data from the Chinese Household Income Project survey and employing combination of the propensity score matching and difference-in-differences methods.The results yield three conclusions.First,the reform affected both the amount and share of household consumption.Specifically,the reform led to an increase in total household consumption,encompassing both medical and nonmedical expenditures.Among these,the proportion of medical consumption increased,while the proportion of nonmedical consumption reduced.Second,the impact of the URRBMI reform varied across consumption categories within nonmedical expenditure.Specifically,consumption for education and entertainment industries are positively impacted by the URRBMI reform in terms of both quantity and proportion.Third,low-income households benefit more from the URRBMI reform compared to middle-and high-income households.The main channels through which the URRBMI reform affects household consumption were the price effect and the crowding out effect on precautionary savings.展开更多
To explore the mechanism of entry to the self-employed sector in urban China,this study tested two hypotheses:the entrepreneurship hypothesis and the disguised unemployment hypothesis,investigating the impact of mass ...To explore the mechanism of entry to the self-employed sector in urban China,this study tested two hypotheses:the entrepreneurship hypothesis and the disguised unemployment hypothesis,investigating the impact of mass entrepreneurship and innovation policies on business start-ups.Three main findings emerged.First,the entrepreneurship hypothesis was rejected for both local urban residents and migrants in 2013 but was supported for both groups in 2018.Second,the causality relationship between mass entrepreneurship and innovation policies and business starts-ups was not significant.Third,the results differed by group.The entrepreneurship hypothesis was supported for the younger generation of migrants in 2018 but was clearly rejected for the less educated,both in the local urban resident and migrant groups in 2013 and 2018.Robustness checks confirmed these conclusions.展开更多
A generalized Volterra lattice with a nonzero boundary condition is considered by virtue of the inverse scattering transform.The two-sheeted Riemann surface associated with the boundary problem is transformed into the...A generalized Volterra lattice with a nonzero boundary condition is considered by virtue of the inverse scattering transform.The two-sheeted Riemann surface associated with the boundary problem is transformed into the Riemann sphere by introducing a suitable variable transformation.The associated spectral properties of the lattice in single-valued variable was discussed.The constraint condition about the nonzero boundary condition and the scattering data is found.展开更多
Soybean residue (SR) is a by-product of bean product processing with potential usefulness as a fermentation medium. However, the fermentation efficiency of SR is limited due to its low reducing sugar content. In this ...Soybean residue (SR) is a by-product of bean product processing with potential usefulness as a fermentation medium. However, the fermentation efficiency of SR is limited due to its low reducing sugar content. In this study, a method of microwave radiation combined with cellulase hydrolysis (MCH) was developed to increase the reducing sugar content of SR, and the effect of treated SR on fermentation by Aspergillus oryzae was evaluated. First, the process parameters, including the reaction time, pH and temperature, were optimized. Second, the effect of treated SR on fermentation by A. oryzae was evaluated, including changes in cell proliferation and protease viability. The results showed that the MCH method capitalized on the advantages of microwave radiation and cellulase and promoted the enzymatic hydrolysis of fibrous polysaccharides in the crystallization zone of SR. The reducing sugar content of SR significantly increased from 0.42 to 0.98 mg/mL after MCH treatment. In addition, treated SR effectively promoted the proliferation of A. oryzae , and the protease activity reached 111 U/mL after 3 days of fermentation. The results of this study suggested that the MCH method can effectively increase the reducing sugar content of SR to expand its use as a fermentation medium.展开更多
基金supported by the National Natural Science Foundation of China(32402523)the Science and Technology Program of Henan Province,China(232102111083,242102111120)the Natural Science Foundation of Henan Province,China(252300420179).
文摘While bagged flat peaches gain increasing consumer preference,the bagging process inhibits anthocyanin production and fruit coloration in most peach cultivars.Certain peach cultivars,including the rapidly expanding‘Zhongyoupan 9’,demonstrate a light-independent anthocyanin biosynthesis pattern and accumulate anthocyanins under artificial darkness.The underlying molecular mechanisms,however,remain unelucidated.This study examined two flat peach varieties:‘Zhongpan 17’,exhibiting light-dependent anthocyanin biosynthesis,and‘Zhongyoupan 9’,displaying light-independent anthocyanin biosynthesis.The pericarp of‘Zhongyoupan 9’contained substantially higher anthocyanin levels compared to‘Zhongpan 17’.Metabolomic analysis identified the marked increase in anthocyanins,particularly cyanidin-3-O-glucoside,as the primary factor in‘Zhongyoupan 9’coloration under artificial darkness.Transcriptomic analyses revealed that PpHY5(long hypocotyl 5)showed upregulation in‘Zhongyoupan 9’but downregulation in‘Zhongpan 17’,with its expression pattern correlating positively with color changes in both varieties.The role of PpHY5 in positively regulating anthocyanin biosynthesis was confirmed through reduced anthocyanin levels in peach fruits treated with a PpHY5 virus-induced gene-silencing construct.These findings suggest that the PpHY5 regulates red color development in‘Zhongyoupan 9’under artificial darkness.
基金support from the Major State Basic Research Development Program (No. 51312)the Fundamental Research Funds for the Central Universities(No. HIT.KLOF.2010046)
文摘Considering the unique properties of small spacecraft, such as light weight, low power-consumption and high heat flux density, a new kind of lightweight boron carbide （B4C） radiation-protection coating material was proposed. New techniques for preparing LSMO thermal control coating and B4C radiation-protection coating were developed. The sample piece of multi-functional structure was manufactured by using the proposed materials, and a series of performance tests, such as thermal control and radiation-protection behaviors were evaluated. Test results show that： the emissivity of the multi-functional structure varies from 0.42 to 0.86 at 240 K to 353 K and the phase transition temperature is about 260 K. The electron radiation-protection ability of the multi-functional structure is 3.3 times better than that of Al material. The performance index of this multi-functional structure can meet the requirements for space application in on-board electronic equipment.
基金Supported by Sichuan Science and Technology Program (2021YFN0009)Science and Technology Project of General Administration of Customs(2020HK161)+1 种基金Key Project of Ningbo Public Welfare Science and Technology Program (2021S024)Technology Development Project of Ningbo Joysun Product Testing Service Company (2020ZS003)。
文摘[Objectives]The infection symptoms of cyst nematodes were found in Yuexi, Sichuan. In order to identify the pathogen, the isolated nematodes were identified by morphology and molecular biology. [Methods] The potato roots and soil around the roots were collected, the nematodes in the roots were stained and observed, and the cysts were separated by the simple floating method. The second-stage juveniles(J2 s), females and cysts were found, and they were photographed and morphologically measured. The DNA of cysts and J2 s were extracted and identified by species-specific PCR. The DNA sequences of 18 S gene, 28 S D2-D3 region and ITS region in ribosomal DNA were obtained. Sequences of some cyst nematode species were downloaded from GenBank for sequence alignment, and MrBayes 3.2.3 software was used to construct a Bayesian phylogenetic tree. [Results] The nematodes could invade hosts’ root system. The basal knobs of J2 s was nearly round and inclined backward;the average length of the stylet was shorter than 23 μm;the Granek ratio of cysts was greater than or equal to 3, which is highly consistent with that of Globodera rostochiensis. The DNA templates of three cysts and four J2 s were amplified by species-specific PCR, and a band of about 430 bp was obtained. After further sequencing, the length was 434 bp, which is consistent with G. rostochiensis. The evolutionary analysis of rDNA 18 S and 28 S showed that the cyst nematode population was a Globodera species, and further evolutionary analysis of ITS gene confirmed that the population was G. rostochiensis. [Conclusions] The nematodes are G. rostochiensis, which is a quarantine species of great concern to both domestic and import quarantine. Once introduced and colonized, it is hard to eradicate. It is necessary to establish a monitoring system as soon as possible, strengthen the quarantine, supervision and management, increase investment in G. rostochiensis research and development, and develop detection and control technologies, so as to escort the healthy and sustainable development of China’s potato industry.
文摘Climate change and human activities have great implications for hydrological process and water projects planning. In order to evaluate the impacts on stream-flow, statistical methods and SWAT model are applied to this research. The results indicate that the abrupt change year (1965) of annual stream-flow is chosen as the split point of natural and human influenced (particularly reservoirs) periods. The calibrated SWAT model is proved to be applicable in this catchment and is used to simulate the monthly runoff which can be regarded as the natural runoff induced by climate change. A major finding of this study is that the reservoir regulations have apparently altered the monthly and seasonal stream-flow regimes. By quantifying the impacts of climate variation and human activities, the decreasing trend of annual stream-flow is found, and human activities are proved to be the dominant role in the catchment. This research improves our knowledge of hydrological responses to natural and artificial factors, and provides a better understanding for the future reservoir regulations.
基金the National Natural Science Foundation of China(No.62301056)the Fundamental Research Funds for Central Universities(No.2022QN005).
文摘Moderate exercise contributes to health, but excessive exercise may lead to physicalinjury or even endanger life. It is pressing for a device that can detect the intensity of exercise.Therefore, in order to enable real-time detection of exercise intensity and mitigate the risks of harmfrom excessive exercise, a exercise intensity monitoring system based on the heart rate variability(HRV) from electrocardiogram (ECG) signal and linear features from phonocardiogram (PCG)signal is proposed. The main contributions include: First, accurate analysis of HRV is crucial forsubsequent exercise intensity detection. To enhance HRV analysis, we propose an R-peak detectorbased on encoder-decoder and temporal convolutional network (TCN). Experimental resultsdemonstrate that the proposed R-peak detector achieves an F1 score exceeding 0.99 on real high-intensity exercise ECG datasets. Second, an exercise fatigue monitoring system based on multi-signal feature fusion is proposed. Initially, utilizing the proposed R-peak detector for HRV extractionin exercise intensity detection,which outperforms traditional algorithms, with the system achieving a classification performance of 0.933 sensitivity, 0.802 specificity, and 0.960 accuracy. To further improve the system, we combine HRV with the linear features of PCG. Our exercise intensitydetection system achieves 90.2% specificity, 96.7% recall, and 98.1% accuracy in five-fold cross-validation.
基金the National Natural Sci-ence Foundation of China(No.62301056)the Fundamental Research Funds for Central Universities(No.2022QN005).
文摘Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical activity.As a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovascular information,and their data acquisition devices are quiteconvenient.In this study,a novel hybrid approach of fractional Fourier transform(FRFT)com-bined with linear and discrete wavelet transform(DWT)features extracted from PCG is proposedfor PCG multi-class classification.The proposed system enhances the fatigue detection performanceby combining optimized FRFT features with an effective aggregation of linear features and DWTfeatures.The FRFT technique is employed to convert the 1-D PCG signal into 2-D image which issent to a pre-trained convolutional neural network structure,called VGG-16.The features from theVGG-16 were concatenated with the linear and DWT features to form fused features.The fusedfeatures are sent to support vector machine(SVM)to distinguish six distinct fatigue levels.Experi-mental results demonstrate that the proposed fused features outperform other feature combinationssignificantly.
基金financially supported by Key-Area Research and Development Program of GuangDong Province(2019B010942001)National Key R&D Program of China(No.2017YFB0703100)+1 种基金the National Natural Science Foundation of China[grant numbers 51822103,51731009 and 51671068]the Fundamental Research Funds for the Central Universities[grant number HIT.BRETIV.201902]。
文摘A novel Ti cored wire containing Ti B2,Al60 V40 and Ti6 Al4 V mixed powders was developed for wirefeed arc deposition of Ti B/Ti composite coating,to enhance the hardness and wear resistance of Ti alloy.Results showed that after experiencing several chemical reactions,the wire was melted in the arc zone and turned into nonuniform droplets composed of Ti-Al-V-B melt and undecomposed Ti B2 particles.With the increase of welding current,the detachment time of droplet shortened while the transfer frequency accelerated,accompanied by the improvement in coating surface quality.The spatial distribution of Ti B whiskers in coating was governed by welding current.A uniform distribution could be achieved as welding current was sufficient at the expense of elevated dilution ratio,while increasing wire feeding speed could compensate the dilution loss of Ti B whisker to some extent.The decomposition process of Ti B_(2)particles and the microstructure evolution mechanism of coating was discussed in detail.The optimum coating possessed uniform microstructure,relatively low dilution ratio,and high hardness(639.1 HV_(0.5))as compared with Ti6 Al4 V substrate(326 HV_(0.5)).Indentation morphology analysis verified the excellent performance was ascribed to the load-sharing strengthening of Ti B whiskers.This study provides a high-efficiency fabrication method for the ever-developing titanium matrix composites(TMCs)coating.
文摘Using CHIP （Chinese Household Income Project Survey） data and the sample selection bias corrected wage function model, this paper estimated changes in wage structure in China by ownership types （SOEs, COEs, FEs, and PEs） in 1995 and 2007. The major conclusions are as follows. First, effects of education on wage levels in SOEs and FEs become greater, while education effects decrease in SOEs and PEs under economic transition periods; firm-specific human capital becomes more important in the wage determination mechanism along with market-oriented reforms in SOEs, PEs, and FEs; age effect decreases in SOEs and COEs, but it becomes greater in PEs and FEs. Second, there exist wage structure differences between sectors by wage distributions. For example, in 2007, in SOEs, education return rates are higher for the low-wage and middle-wage groups, and the effect is the highest at the 40th percentile. However in COEs and FEs, education return rates are higher for the high-wage groups, and the effect is the highest at the 70th percentile in COEs and at the 70th percentile in FEs. Tenure effects are greater in the middle-wage groups （40th-80th） in SOEs, COEs, and FEs, and age effects are greater in the low-wage groups （5th-30th） in SOEs, FEs, and PEs.
基金Fundamental Research on Impact Toughness and Response Mechanism of Bamboo-woven Structural Materials Funded of International Center for Bamboo and Rattan(1632020016).
文摘Drop weight impact tester was used to accurately measure the bending impact resistance of various parts of Phyllostachys edulis,commonly known as moso bamboo,with a growth cycle of 3–8 years.Cellulose crystallinity in the bottom(B),middle(M)and top(T)of bamboo at different ages was calculated using peak height analysis in X-ray diffraction.Heatmap of Spearman correlation analysis was used to represent the correlation between chemical composition and impact mechanics.The breaking load(BL),fracture energy(FE)and impact deflection(ID)of 3–8-year-old bamboo were found to be in the range of~670–2120 N,~5.17–15.55 J,and~3.60–~17.76 mm,respectively.As the growth period of bamboo rises,the cellulose crystallinity at the B and T decreases first and then increases,while that for the M increases first and then remains stable.Similarly,the bending impact performance of bamboo was found to become stable with its growth and age.The flexural impact and toughness of the 4-year-old bamboo base material were better than other specimens.The enhancement in the bending impact properties of bamboo at different growth periods was influenced by the lignin content,while the value of FE was mainly positively correlated with ash,cold and hot water extracts and benzyl alcohol content.However the content of holocellulose and pentosan,air-dry density and,base density negatively influenced the FE.With the change in the height of the bamboo,the correlation between its impact mechanical properties and chemical composition gradually decreased.This study provides data support and theoretical basis for the age-appropriate thinning and application of moso bamboo.
文摘The magnetron sputtered La0.7Sr0.3MnO3 films were implanted with different doses (5 ′ 1015 ions×cm?2 and 5 ′ 1016 ions×cm-2) of Al ions at different negative pulsed voltages (30 kV and 50 kV) by plasma based ion implantation and then annealed at 973 K for 1 h in air. The microstructure, surface morphologies, surface roughness, metal-insulator transition and room temperature emittance properties of the post-implantation annealed films were investigated and compared with those of the La0.7Sr0.3MnO3 film annealed at 973 K for 1 h in air. The results indicate that the post- implantation annealed films show single perovskite phase and obvious (100) preferred orientation growth. The Mn-O bond length, surface roughness and metal-insulator transition temperature (TMI) of the films can be effectively adjusted by changing implantation voltage or implantation dose of Al ions. However, the change of implantation parameters just has a small effect on room temperature emittance of the films. Compared with the annealed film, the post-implantation annealed films have shorter Mn-O bond length and lower room temperature emittance. The TMI of the films implanted at low voltage is lower than that of the annealed film, which mainly results from the degradation of oxidization during annealing process and the part displacement of Mn3+-O2+- Mn4+ double exchange channels by Al3+-O2?-Mn4+. The post-implanted annealed film implanted at 50 kV/5 ′ 1016 ions×cm-2 has a higher TMI than the annealed film, which is 247 K. The increase of TMI of the film implanted with high dose of Al ions at high voltage can be attributed to the improvement of microstructure.
文摘Using the 2000, 2004, and 2006 CHNS longitudinal survey data and econometric methods （random-effect probit regression model and DID methods）, this study conducted an empirical analysis to estimate the impact of NCMS. The major conclusions are as follows. First, predisposing factors, enabling factors, health care need factors, and lifestyle factors affect health care utilization. Second, results using DID methods indicate that NCMS did not affect health care service utilization （outpatient and inpatient） of individuals when ill, but it might increase the possibility of getting a health examination. Third, there is no difference in health care service utilization （both outpatient and inpatient） between the NCMS enrollment group and the non-enrollment group in both working age group （15-59） and the elderly group （60 and over）. Therefore, it can be said that NCMS did not affect the health care utilization in both the group. However, NCMS positively affects disease prevention behavior （visiting the hospital to receive a health examination） in the working age group, but the effect did not appear in the elderly group.
基金supported by the National Key R&D Program of China(No.2023YFD2202101)the National Natural Science Foundation of China(No.32230072)+1 种基金the Foundation of International Centre for Bamboo and Rattan(No.1632023001)the Science and Technology Program of Fujian Province(No.2023N3012).
文摘Disposable plastic straws are small,lightweight,and non-degradable,making them rarely recycled and causing severe environmental pollution.However,the search for suitable alternatives,balanc-ing high performance with low cost,poses a substantial challenge.Inspired by bamboo’s flexibility and toughness,this study proposed an innovative solution:a biodegradable drinking straw fab-ricated by winding ultra-thin bamboo slices.The specially prepared bamboo slices demonstrated high tensile strength,exceptional flexibility for bending,and the ability to withstand repeated torsion.To address natural issues of color-producing group migration and mold susceptibility,the bamboo slices underwent simultaneous soaking and ultrasonic treatment.The resulting bam-boo straws exhibited remarkable properties with compressive strength of 16.42-19.01 MPa and bending strength of 14.21-15.02 MPa,which matched or exceeded those of commercial paper straws and were significantly higher than those of polypropylene(PP)and polylactic acid(PLA)straws.When exposed to various beverages,bamboo straws retained their structural integrity,absorbed significantly less water than paper straws,and the wet strength was 4.36 times greater than that of paper straws.Moreover,bamboo drinking straws exhibited low production costs and garnered widespread consumer approval.The strategy for industrial-scale production of bamboo straws offers significant potential for replacing plastic straws.
基金Supported by the Key Science and Technology Project of Henan Province(252102321006 and 242102320037)Henan Key Laboratory of Agrometeorological Safeguard Application Techniques(KM202220,KQ202022,and KQ202425)+2 种基金Fengyun Application Pioneer-ing Project(20220111)Central Regional Weather Modification Capacity Building Project of China Meteorological Administration,Weather Modification Research Experiment in Danjiangkou Reservoir(ZQC-H22255)Research Experiment on Rain&Snow Enhancement Through Cloud Seeding in Stratiform Clouds with Embedded Convection in Central China(Shangqiu)(ZQC-H22256)。
文摘Previous satellite observations have identified the appearance of“cloud trough”(or“cloud trench”),with cloud tops visually collapsed following airborne cloud seeding operation,demonstrating the effect of weather modification.However,refined observations of troughed clouds and associated microphysical processes are still notably scarce,especially those obtained via in-situ aircraft measurements.In this study,variations in cloud microphysics associated with and without troughed clouds along an airborne stratiform cloud seeding path over central China on 15 December 2019 are analyzed and compared based on aircraft measurements,ground-based radar observations,and FY-4A satellite imagery.The results are as follows.(1)The troughed clouds were mainly formed to the northeast of the flight path and were observed only in some parts of the seeded stratiform clouds.The seeding tracks became visible starting from 60 min after seeding and persisted for approximately 3 h,covering a maximum width of 30–40 km in FY-4A imagery.Radar echo enhancements can be observed by a ground-based radar at some parts of the seeding tracks.(2)The troughed clouds were observed only when the ambient air temperature(T)was≤-7℃,a condition favoring high nucleation efficiency of silver iodide(Ag I)aerosols,whereas no cloud troughs formed at higher temperatures.(3)The troughed clouds with strong radar echoes(i.e.,large precipitation)corresponded to regions with high values(>0.1 g m^(-3))of supercooled water content after cloud seeding,which facilitated the growth of precipitation particles.(4)Within the troughed clouds,the cloud optical thickness and cloud top height decreased,while the effective radii of cloud particles increased by nearly 10μm.These results provide valuable guidance for optimizing cold cloud seeding conditions in artificial rainfall enhancement.Meanwhile,the presence of high supercooled water content,particularly the threshold of supercooled water content,is a critical factor for strong precipitation,which necessitates further studies.
基金National Natural Science Foundation of China (21206179) Natural Science Foundation of Shandong Province (ZR2018MB033) State Key Laboratory of Chemical Engineering,China (SKL-ChE-15A03).
文摘Hexagonal tungsten trioxide (h-WO3)microspheres were synthesized by a hydrothermal method,with ammonium paratungstate and hydrochloric acid as the raw materials.The effects of the process parameters on the phase compositions and morphologies of the products were investigated.The results showed that the hydrothermal temperature and molar ratio of the raw materials were important for avoiding the formation of impurity phases,namely WO3.0.33H2Oand WO3.H2O.The pure-phase h-WO3microspheres had a specific surface area of 40.0m^2/g,and were assembled from nanorods.The microspheres were used to support Pd,and the obtained Pd/h-WO3catalyst showed excellent catalytic activity in the hydrogenation of styrene under mild conditions,with a turnover frequency 0f 3050h^-1.The catalyst was recycled five times without loss of activity,i.e.,the supported catalyst had good recyclability.
基金the National Social Science Foundation of China(No.19ZDA116)the Japan Society for the Promotion of Science(No.20H01512)the Fundamental Research Funds for the Central Universities.
文摘This paper investigates the causal relationship between the Urban and Rural Resident Basic Medical Insurance(URRBMI)reform and household consumption in urban China using data from the Chinese Household Income Project survey and employing combination of the propensity score matching and difference-in-differences methods.The results yield three conclusions.First,the reform affected both the amount and share of household consumption.Specifically,the reform led to an increase in total household consumption,encompassing both medical and nonmedical expenditures.Among these,the proportion of medical consumption increased,while the proportion of nonmedical consumption reduced.Second,the impact of the URRBMI reform varied across consumption categories within nonmedical expenditure.Specifically,consumption for education and entertainment industries are positively impacted by the URRBMI reform in terms of both quantity and proportion.Third,low-income households benefit more from the URRBMI reform compared to middle-and high-income households.The main channels through which the URRBMI reform affects household consumption were the price effect and the crowding out effect on precautionary savings.
基金supported financially by the Japan Society for the Promotion of Science from the Ministry of Education,Culture,Sports,Sciences and Technology of Japan(KAKENHI:Nos.20H01512,20H01489).
文摘To explore the mechanism of entry to the self-employed sector in urban China,this study tested two hypotheses:the entrepreneurship hypothesis and the disguised unemployment hypothesis,investigating the impact of mass entrepreneurship and innovation policies on business start-ups.Three main findings emerged.First,the entrepreneurship hypothesis was rejected for both local urban residents and migrants in 2013 but was supported for both groups in 2018.Second,the causality relationship between mass entrepreneurship and innovation policies and business starts-ups was not significant.Third,the results differed by group.The entrepreneurship hypothesis was supported for the younger generation of migrants in 2018 but was clearly rejected for the less educated,both in the local urban resident and migrant groups in 2013 and 2018.Robustness checks confirmed these conclusions.
基金This work was supported by the National Natural Science Foundation of China(Grant No.11471295)The third author’s work was partially supported by the President’s Endowed Professorship program of the University of Texas system.
文摘A generalized Volterra lattice with a nonzero boundary condition is considered by virtue of the inverse scattering transform.The two-sheeted Riemann surface associated with the boundary problem is transformed into the Riemann sphere by introducing a suitable variable transformation.The associated spectral properties of the lattice in single-valued variable was discussed.The constraint condition about the nonzero boundary condition and the scattering data is found.
基金support of this research.This research was supported by a Horizontal Scientific Research Project Grant(J2021-27).
文摘Soybean residue (SR) is a by-product of bean product processing with potential usefulness as a fermentation medium. However, the fermentation efficiency of SR is limited due to its low reducing sugar content. In this study, a method of microwave radiation combined with cellulase hydrolysis (MCH) was developed to increase the reducing sugar content of SR, and the effect of treated SR on fermentation by Aspergillus oryzae was evaluated. First, the process parameters, including the reaction time, pH and temperature, were optimized. Second, the effect of treated SR on fermentation by A. oryzae was evaluated, including changes in cell proliferation and protease viability. The results showed that the MCH method capitalized on the advantages of microwave radiation and cellulase and promoted the enzymatic hydrolysis of fibrous polysaccharides in the crystallization zone of SR. The reducing sugar content of SR significantly increased from 0.42 to 0.98 mg/mL after MCH treatment. In addition, treated SR effectively promoted the proliferation of A. oryzae , and the protease activity reached 111 U/mL after 3 days of fermentation. The results of this study suggested that the MCH method can effectively increase the reducing sugar content of SR to expand its use as a fermentation medium.
