Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout a...Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout analyses were based on continuum mechanics.In addition to failure in intact rocks,wellbore breakouts can also be initiated along natural discontinuities,e.g.weak planes and fractures.Furthermore,the conventional models in wellbore breakouts with uniform distribution fractures could not reflect the real drilling situation.This paper presents a fully coupled hydro-mechanical model of the SB-X well in the Tarim Basin,China for evaluating wellbore breakouts in heavily fractured rocks under anisotropic stress states using the distinct element method(DEM)and the discrete fracture network(DFN).The developed model was validated against caliper log measurement,and its stability study was carried out by stress and displacement analyses.A parametric study was performed to investigate the effects of the characteristics of fracture distribution(orientation and length)on borehole stability by sensitivity studies.Simulation results demonstrate that the increase of the standard deviation of orientation when the fracture direction aligns parallel or perpendicular to the principal stress direction aggravates borehole instability.Moreover,an elevation in the average fracture length causes the borehole failure to change from the direction of the minimum in-situ horizontal principal stress(i.e.the direction of wellbore breakouts)towards alternative directions,ultimately leading to the whole wellbore failure.These findings provide theoretical insights for predicting wellbore breakouts in heavily fractured rocks.展开更多
Addressing the existing gap in ethical research surrounding distinct technical characteristics of Robotic Process Automation enhanced with Artificial Intelligence (AI-RPA), this analysis examines the unique ethical di...Addressing the existing gap in ethical research surrounding distinct technical characteristics of Robotic Process Automation enhanced with Artificial Intelligence (AI-RPA), this analysis examines the unique ethical dimensions by positioning AI-RPA as a distinct technological subdivision. From an analytical perspective, this study highlights key characteristics such as minimal reliance on programming, rapid development cycles, and restricted algorithmic control, which differentiate AI-RPA from traditional AI systems. These characteristics underscore the need for tailored ethical considerations, to identify ethical perils within AI-RPA’s technological origins. By positioning AI-RPA as a distinct subdivision and examining its unique characteristics alongside their emerging ethical challenges, this paper enriches the evolving discourse on AI ethics, providing valuable insights for researchers, policymakers, and organizations implementing AI-RPA technologies.展开更多
Adolescence is a crucial period marked by significant developmental changes,during which risk-taking behaviors can be both a normative part of development and a potential source of concern.However,prior research has f...Adolescence is a crucial period marked by significant developmental changes,during which risk-taking behaviors can be both a normative part of development and a potential source of concern.However,prior research has focused predominantly on the adverse aspects of risk-taking(i.e.,negative risk-taking),overlooked the positive counterpart(i.e.,positive risk-taking),and lacked a detailed examination of both.This study aims to elucidate the distinct characteristics and interrelationships of positive and negative risk-taking behaviors among adoles-cents and to identify the key factors that influence these behaviors.Through a comprehensive synthesis of theoretical and empirical literature,we explore the multifaceted nature of risk-taking,highlighting its complex influencing factors,including individual traits,family dynamics,peer influence,school environment,and broader community contexts.By identifying the shared and unique factors contributing to positive and negative risk-taking behaviors,we can enable adolescents to navigate this complex stage of life and design targeted interventions.Future research directions include the application of person-centered approaches,the implementation of longitudinal tracking and the interactive effects of influencing factors,among other aspects.展开更多
By using multi-objective analysis method, five architectural tourist sites with Lingnan characteristics were selected. Through the analysis on relevant data obtained by GIS, spatial analysis research had been conducte...By using multi-objective analysis method, five architectural tourist sites with Lingnan characteristics were selected. Through the analysis on relevant data obtained by GIS, spatial analysis research had been conducted on competitiveness of Lingnan distinctive architectural tourist cultural sites in Guangdong Province and some conclusions had been obtained.展开更多
In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tes...In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising.展开更多
This paper presents a three-dimensional fully hydro-mechanical coupled distinct element study on fault reactivation and induced seismicity due to hydraulic fracturing injection and subsequent backflow process,based on...This paper presents a three-dimensional fully hydro-mechanical coupled distinct element study on fault reactivation and induced seismicity due to hydraulic fracturing injection and subsequent backflow process,based on the geological data in Horn River Basin,Northeast British Columbia,Canada.The modeling results indicate that the maximum magnitude of seismic events appears at the fracturing stage.The increment of fluid volume in the fault determines the cumulative moment and maximum fault slippage,both of which are essentially proportional to the fluid volume.After backflow starts,the fluid near the joint intersection keeps flowing into the critically stressed fault,rather than backflows to the wellbore.Although fault slippage is affected by the changes of both pore pressure and ambient rock stress,their contributions are different at fracturing and backflow stages.At fracturing stage,pore pressure change shows a dominant effect on induced fault slippage.While at backflow stage,because the fault plane is under a critical stress state,any minor disturbance would trigger a fault slippage.The energy analysis indicates that aseismic deformation takes up a majority of the total deformation energy during hydraulic fracturing.A common regularity is found in both fracturing-and backflow-induced seismicity that the cumulative moment and maximum fault slippage are nearly proportional to the injected fluid volume.This study shows some novel insights into interpreting fracturing-and backflowinduced seismicity,and provides useful information for controlling and mitigating seismic hazards due to hydraulic fracturing.展开更多
Distinctness, Uniformity and Stability （DUS） testing is the technical base of Plant Variety Protection （PVP） and the scientific basis for the approval of Plant Breeder＇s Rights （PBR）. DUS Test Guidelines are no...Distinctness, Uniformity and Stability （DUS） testing is the technical base of Plant Variety Protection （PVP） and the scientific basis for the approval of Plant Breeder＇s Rights （PBR）. DUS Test Guidelines are not only the technical manuals for the DUS testing authorities to conduct the testing, but also the technical standards for the competent authorities to examine the DUS of new varieties of plants. Tea plant, originated from Yunnan Province, China, is a very important woody cash species in the world. The International Union for the Protection of New Varieties of Plants （UPOV） DUS Test Guidelines for tea plant is the first Test Guidelines prepared by China for the UPOV. In this article, the subject, selection, and determination of characteristics, states of expression of characteristics and the selection of example varieties, assessment of the UPOV DUS Test Guidelines for tea plant were elucidated in detail. Finally, the proposal of PVP for tea plant in China was also proposed. The preparation of UPOV DUS Test Guidelines for tea plant will have important significance both for promoting the development of PVP and increasing the status of international PVP fields for China.展开更多
Using monthly mean sea ice velocity data obtained from the International Arctic Buoy Programme （IABP） for the period of 1979–1998 and the monthly mean NCEP/NCAR re-analysis dataset （1960–2002）, we investigated t...Using monthly mean sea ice velocity data obtained from the International Arctic Buoy Programme （IABP） for the period of 1979–1998 and the monthly mean NCEP/NCAR re-analysis dataset （1960–2002）, we investigated the spatiotemporal evolution of the leading sea ice motion mode （based on a complex correlation matrix constructed of normalized sea ice motion velocity） and their association with sea level pressure （SLP） and the predominant modes of surface wind field variability. The results indicate that the leading winter sea ice motion mode’s spatial evolution is characterized by two alternating and distinct sea ice modes, or their linear combination. One mode （M1） shows a nearly closed cyclonic or anti-cyclonic circulation anomaly in the Arctic Basin and its marginal seas, resembling to a large extent the response of sea ice motion to the Arctic Oscillation （AO）, as many previous studies have revealed. The other mode （M2） displays a coherent cyclonic or anti-cyclonic circulation anomaly with its center close to the Laptev Sea, which has not been identified in previous observational studies. In fact, M1 and M2 respectively reflect the responses of sea ice motion to two predominant modes of winter surface wind variability north of 70 ？ N, which well correspond, with slight differences, to the first two modes of EOF analysis of winter monthly mean SLP north of 70 ？ N. These slight differences in SLP anomalies lead to a difference of M2 from the response of sea ice motion to the dipole anomaly. Although the AO significantly influences sea ice motion, it is not crucial for the existence of M1. The new sea ice motion mode （M2） has the largest variance and clearly differs from the response of winter monthly mean sea ice motion to the dipole anomaly in SLP fields, and corresponding SLP anomalies also show differences compared to the dipole anomaly. This study indicates that in the Arctic Basin and its marginal seas, slight differences in SLP anomaly patterns can force distinctly different sea ice motion anomalies.展开更多
Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair ...Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair of varieties grown side-by-side, is time-consuming and is not suitable for the assessment of hundreds of samples. The objective of this study was to develop a procedure for the assessment of wheat variety distinctness using simple sequence repeat（SSR） markers. A comparison between the molecular and morphological profile of 797 varieties was made. On the basis of the comparison, pairs of varieties with a genetic similarity value（GSV） ≤90% were deemed to be distinct, accounting for ~85% of varieties assessed in wheat regional trials. For the remaining ~15% of varieties, GSVs between different varieties were 〉90%, among which ~35% were not distinct and the other ~65% were distinct. Therefore, if given a GSV〉90%, the pairs of varieties should be morphologically assessed in the field. To avoid any errors in the assessments, we proposed the elimination of contaminant plants from the sample before comparing the varietal genotypes, scoring of the genotype at each locus with a pair of allele numbers when constructing a molecular profile, and faithfully recording two alleles at a non-homozygous locus. To reduce the workload and cost, a three-grade markers comparison among varieties is suggested. In addition, 80 SSR markers and a technical procedure for assessment of wheat variety distinctness have been proposed. Based on the procedure, the distinctness assessment of ~85% of all wheat varieties is completed in our laboratory annually. Consequently, total field assessment has been reduced considerably.展开更多
The objectives of this study were to construct a database of expressed sequence tag (EST)-simple sequence repeat (SSR) markers to identify lettuce cultivars. A set of 370 EST-SSR primer pairs were applied for fingerpr...The objectives of this study were to construct a database of expressed sequence tag (EST)-simple sequence repeat (SSR) markers to identify lettuce cultivars. A set of 370 EST-SSR primer pairs were applied for fingerprinting the lettuce cultivars. Fifty-eight EST-SSR markers showed hy-per-variability and were able to differentiate 92 cultivars. A total of 176 polymorphic amplified fragments were obtained by the 58 markers, and two to eight SSR alleles were detected for each l°Cus with an average of three alleles per locus. Average polymorphism information content (PIC) was 0.425, ranging from 0.022 to 0.743. Cluster analysis was based on Jaccard’s distance coefficients using the method of unweighted pair group. In this method we used arithmetical averages (UPGMA) algorithm categorized 4 major groups, which were in accordance to morphological traits. The eight cultivars of three groups with 100% genetic similarity through SSR analysis were investigated by phenotypic traits. These cultivars including these pairs are very similar in 27 morphological characteristics. Therefore, these EST-SSR markers could be used to select similar cultivars through management of reference collection to complement distinctiveness test of lettuce cultivars.展开更多
The intertidal zone is a complex coastal area exposed to a wide variety of environmental factors. During low tide, rocky pools are exposed to air for several hours throughout the day, and environmental conditions such...The intertidal zone is a complex coastal area exposed to a wide variety of environmental factors. During low tide, rocky pools are exposed to air for several hours throughout the day, and environmental conditions such as temperature and salinity are highly variable. Fish communities that inhabit these tide pools are also exposed to environmental variability;therefore it is important to look at fish community structure in relation to important environmental factors such as temperature, salinity and dissolved oxygen on tide pools during spring tides, time of greater exposure to air. Therefore, the aim of the present study was to analyze the variation of the taxonomic distinctness of intertidal fish communities considering temperature, salinity and dissolved oxygen of the water that remains trapped in the tide pools during low tide. Visual census surveys were carried out monthly, from January to December 2015, in the intertidal zone of El Faro during spring tides on full moon days, when fluctuations of environmental variables are significant. Total extension of the census surveys was 156 × 5 m (780 m2). A total of 145 tide pools were sampled and divided in three groups (small, medium and large) according to size and depths that ranged from 20 to 45 cm. Temperature, salinity and dissolved oxygen fluctuate throughout the year of study. Thermal difference between open ocean and tide pools ranged from 3.5°C to 4.5°C. A total of 3757 organisms from 22 species, 12 families, four orders and one class were recorded. When comparing taxonomic distinctness and average taxonomic distinctness between months and tide pools of different sizes, values fell within the confidence intervals in the tunnel and were located close to the mean.展开更多
Atmospheric lower-power pulsed microwave argon cold plasma jets are obtained by using coaxial transmission line resonators in ambient air.The plasma jet plumes are generated at the end of a metal wire placed in the mi...Atmospheric lower-power pulsed microwave argon cold plasma jets are obtained by using coaxial transmission line resonators in ambient air.The plasma jet plumes are generated at the end of a metal wire placed in the middle of the dielectric tubes.The electromagnetic model analyses and simulation results suggest that the discharges are excited resonantly by the enhanced electric field of surface plasmon polaritons.Moreover,for conquering the defect of atmospheric argon filamentation discharges excited by 2.45-GHz of continued microwave,the distinctive patterns of the plasma jet plumes can be maintained by applying different gas flow rates of argon gas,frequencies of pulsed modulator,duty cycles of pulsed microwave,peak values of input microwave power,and even by using different materials of dielectric tubes.In addition,the emission spectrum,the plume temperature,and other plasma parameters are measured,which shows that the proposed pulsed microwave plasma jets can be adjusted for plasma biomedical applications.展开更多
New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and...New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and obviously adjusted by increased slurry temperature corresponding to change in distinctive acoustic properties.Moreover,density of all IBPIF kept at only 12-17 kg/m3.With increasing slurry temperature from 0℃to 40℃,cell size and window opening rate gradually increased from 553μm to 791μm and from 6.85%to 58.46%,respectively.In this study,IBPIF generated by slurries at 0℃(marked as PIF-2)and 40℃(marked as PIF-6)showed best and distinctive acoustic behavior in 315-800 Hz and 800-6300 Hz regions,respectively.After acoustic behavior study of combined IBPIF prepared by stitching combination between two distinctive acoustic IBPIFs,results showed that only when PIF-6 sheet used as sound receiving surface even though with thickness of only 10 mm could the combined IBPIF possess the best acoustic level in 800-6300 Hz region as PIF-6.Furtherly,acoustic behavior in 315-800 Hz region could be significantly enhanced by increasing thickness of PIF-2 and could reach or close to the best acoustic level.展开更多
Brand construction plays an increasingly important role in marketing and competition in modern agricultural industry. There are problems in brand construction of tropical distinctive agricultural products in Hainan,in...Brand construction plays an increasingly important role in marketing and competition in modern agricultural industry. There are problems in brand construction of tropical distinctive agricultural products in Hainan,including less famous brand products,weak core competence,strengthening declaration and ignoring management as well as imperfect marketing system,therefore resource integration should be stressed to develop famous brand products and technological innovation should be strengthened to promote core competence of enterprise.展开更多
It has been claimed in the literature that impossibility of faster-than-light quantum communication has an origin of indistinguishability of ensembles with the same density matrix. We show that the two concepts are no...It has been claimed in the literature that impossibility of faster-than-light quantum communication has an origin of indistinguishability of ensembles with the same density matrix. We show that the two concepts are not related.We argue that even with an ideal single-atom-precision measurement, it is generally impossible to produce two ensembles with exactly the same density matrix; or to produce ensembles with the same density matrix, classical communication is necessary. Hence the impossibility of faster-than-light communication does not imply the indistinguishability of ensembles with the same density matrix.展开更多
To retrofit and strengthen existing unreinforced masonry (URM) structures to resist the potential earthquake damages has become an important issue in Australia. In order to secure the performance of URM under seismic ...To retrofit and strengthen existing unreinforced masonry (URM) structures to resist the potential earthquake damages has become an important issue in Australia. In order to secure the performance of URM under seismic loading in the future, a research project was carried out aimed at developing a simple and high strength seismic retrofitting technique for masonry structures. A series of experimental testing on URM walls retrofitted with an innovative technique by cable system have been conducted. The results indicated that both the strength and ductility of the tested speci-mens were significantly enhanced with the technique. An analytical model which is based on Dis-tinct Element Method (DEM) has also been developed to simulate the behaviour of URM walls be-fore and after retrofitting. The model is then further developed by applying a seismic wave to the wall to simulate the wall behavior under earthquake loads before and after retrofitting.展开更多
On the basis of the developmental status of Guangxi distinctive agriculture,the key selection of developing Guangxi distinctive agriculture is analyzed.Its distinctive agriculture contains distinctive plantation,disti...On the basis of the developmental status of Guangxi distinctive agriculture,the key selection of developing Guangxi distinctive agriculture is analyzed.Its distinctive agriculture contains distinctive plantation,distinctive forestry and distinctive breeding.Based on the analysis,two display indices,domestic comparative advantages index and domestic competitiveness,are selected to analyze the competitiveness of Guangxi distinctive agriculture.The results show that at present the overall competitiveness of Guangxi distinctive agriculture is strong,but its competitiveness is reflected on resource advantages and most of the resources are primary agro-products.Accordingly,in the future,Guangxi distinctive agriculture should adopt non-equilibrium developmental strategy;take the great-leap-forward developmental path;apply modern production elements to increase the competitiveness of Guangxi distinctive agriculture.It should lay stress on "three innovation",which includes organization innovation,developing distinctive agricultural firms ;technology innovation,enlarging the scope and scale of agricultural listed companies;financial fund-raising innovation,transforming traditional distinctive agriculture by using high and new technology.展开更多
The risks of metal compounds to human health are highlighted by the ubiquity of exposure and their persistence in the environment.Although compounds of As,Cd,Co,Cr,and Ni are known or“reasonably anticipated”to be ca...The risks of metal compounds to human health are highlighted by the ubiquity of exposure and their persistence in the environment.Although compounds of As,Cd,Co,Cr,and Ni are known or“reasonably anticipated”to be carcinogenic to humans and/or experimental animals, the cellular targets of these health hazards and the underlying mechanisms of their carcinogenic- ity are still unclear.We show in this report that dramatic,time-and dose-dependent cytoskeletal perturbations,especially in the distribution and organization patterns of microtubules and mi- crofilaments,two of the principal components of the cytoskeleton,occurred in 3T3 cells upon exposure to these metal salts.Each metal salt appeared to induce a different,typical pattern of cytoskeletal injury,probably reflecting the specificity of action of each metal ion.These results suggest that the cytoskeleton can indeed act as a target for injury by epigenetic carcinogenic metal compounds in the environment.These findings should help our efforts to understand the mechanisms of action of metal compounds at the subcellular and molecular levels.1989 Academic Press,Inc.展开更多
Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surfac...Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of presplitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.52074312 and 52211530097)CNPC Science and Technology Innovation Foundation(Grant No.2021DQ02-0505).
文摘Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout analyses were based on continuum mechanics.In addition to failure in intact rocks,wellbore breakouts can also be initiated along natural discontinuities,e.g.weak planes and fractures.Furthermore,the conventional models in wellbore breakouts with uniform distribution fractures could not reflect the real drilling situation.This paper presents a fully coupled hydro-mechanical model of the SB-X well in the Tarim Basin,China for evaluating wellbore breakouts in heavily fractured rocks under anisotropic stress states using the distinct element method(DEM)and the discrete fracture network(DFN).The developed model was validated against caliper log measurement,and its stability study was carried out by stress and displacement analyses.A parametric study was performed to investigate the effects of the characteristics of fracture distribution(orientation and length)on borehole stability by sensitivity studies.Simulation results demonstrate that the increase of the standard deviation of orientation when the fracture direction aligns parallel or perpendicular to the principal stress direction aggravates borehole instability.Moreover,an elevation in the average fracture length causes the borehole failure to change from the direction of the minimum in-situ horizontal principal stress(i.e.the direction of wellbore breakouts)towards alternative directions,ultimately leading to the whole wellbore failure.These findings provide theoretical insights for predicting wellbore breakouts in heavily fractured rocks.
文摘Addressing the existing gap in ethical research surrounding distinct technical characteristics of Robotic Process Automation enhanced with Artificial Intelligence (AI-RPA), this analysis examines the unique ethical dimensions by positioning AI-RPA as a distinct technological subdivision. From an analytical perspective, this study highlights key characteristics such as minimal reliance on programming, rapid development cycles, and restricted algorithmic control, which differentiate AI-RPA from traditional AI systems. These characteristics underscore the need for tailored ethical considerations, to identify ethical perils within AI-RPA’s technological origins. By positioning AI-RPA as a distinct subdivision and examining its unique characteristics alongside their emerging ethical challenges, this paper enriches the evolving discourse on AI ethics, providing valuable insights for researchers, policymakers, and organizations implementing AI-RPA technologies.
基金Soft Science Special Project of Gansu Basic Research Plan,No.25JRZA072Youth Project of Philosophy and Social Science Foundation of Gansu Province,No.2024QN015+1 种基金General Project of Philosophy and Social Science Foundation of Gansu Province,No.2024YB049Lanzhou Philosophy and Social Science Planning Project,No.24-B13.
文摘Adolescence is a crucial period marked by significant developmental changes,during which risk-taking behaviors can be both a normative part of development and a potential source of concern.However,prior research has focused predominantly on the adverse aspects of risk-taking(i.e.,negative risk-taking),overlooked the positive counterpart(i.e.,positive risk-taking),and lacked a detailed examination of both.This study aims to elucidate the distinct characteristics and interrelationships of positive and negative risk-taking behaviors among adoles-cents and to identify the key factors that influence these behaviors.Through a comprehensive synthesis of theoretical and empirical literature,we explore the multifaceted nature of risk-taking,highlighting its complex influencing factors,including individual traits,family dynamics,peer influence,school environment,and broader community contexts.By identifying the shared and unique factors contributing to positive and negative risk-taking behaviors,we can enable adolescents to navigate this complex stage of life and design targeted interventions.Future research directions include the application of person-centered approaches,the implementation of longitudinal tracking and the interactive effects of influencing factors,among other aspects.
基金Supported by Basic Tourism which is the Elaborate Course of Guang-zhou Vocational College of Technology and BusinessSubtopic of 863Key Program (2006AA06A306 )+1 种基金Key Item of Weather Bureau of Shandong Province (2009sdqxz16)Geochemical Investigation Data-base (INFO-115-C01-SDB4-06) ~~
文摘By using multi-objective analysis method, five architectural tourist sites with Lingnan characteristics were selected. Through the analysis on relevant data obtained by GIS, spatial analysis research had been conducted on competitiveness of Lingnan distinctive architectural tourist cultural sites in Guangdong Province and some conclusions had been obtained.
基金funded by the National Natural Science Foundation of China (Grant Nos.40730847,40906063 and 41076090)
文摘In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising.
基金supported by the Key Innovation Team Program of Innovation Talents Promotion Plan by Ministry of Science and Technology of China(Grant No.2016RA4059)National Natural Science Foundation of China(Grant Nos.41672268 and 41772286)。
文摘This paper presents a three-dimensional fully hydro-mechanical coupled distinct element study on fault reactivation and induced seismicity due to hydraulic fracturing injection and subsequent backflow process,based on the geological data in Horn River Basin,Northeast British Columbia,Canada.The modeling results indicate that the maximum magnitude of seismic events appears at the fracturing stage.The increment of fluid volume in the fault determines the cumulative moment and maximum fault slippage,both of which are essentially proportional to the fluid volume.After backflow starts,the fluid near the joint intersection keeps flowing into the critically stressed fault,rather than backflows to the wellbore.Although fault slippage is affected by the changes of both pore pressure and ambient rock stress,their contributions are different at fracturing and backflow stages.At fracturing stage,pore pressure change shows a dominant effect on induced fault slippage.While at backflow stage,because the fault plane is under a critical stress state,any minor disturbance would trigger a fault slippage.The energy analysis indicates that aseismic deformation takes up a majority of the total deformation energy during hydraulic fracturing.A common regularity is found in both fracturing-and backflow-induced seismicity that the cumulative moment and maximum fault slippage are nearly proportional to the injected fluid volume.This study shows some novel insights into interpreting fracturing-and backflowinduced seismicity,and provides useful information for controlling and mitigating seismic hazards due to hydraulic fracturing.
文摘Distinctness, Uniformity and Stability （DUS） testing is the technical base of Plant Variety Protection （PVP） and the scientific basis for the approval of Plant Breeder＇s Rights （PBR）. DUS Test Guidelines are not only the technical manuals for the DUS testing authorities to conduct the testing, but also the technical standards for the competent authorities to examine the DUS of new varieties of plants. Tea plant, originated from Yunnan Province, China, is a very important woody cash species in the world. The International Union for the Protection of New Varieties of Plants （UPOV） DUS Test Guidelines for tea plant is the first Test Guidelines prepared by China for the UPOV. In this article, the subject, selection, and determination of characteristics, states of expression of characteristics and the selection of example varieties, assessment of the UPOV DUS Test Guidelines for tea plant were elucidated in detail. Finally, the proposal of PVP for tea plant in China was also proposed. The preparation of UPOV DUS Test Guidelines for tea plant will have important significance both for promoting the development of PVP and increasing the status of international PVP fields for China.
基金supported by Interactionsof the External Forcing in the Northern Mid-high Latitudes with Atmospheric Circulations (GYHY200906017)the Coordinated Observation and Prediction of Earth System(COPES) project (GYHY200706005)the National Natural Science Foundation of China (Grant No. 40875052),and the Alaska Ocean Observing System (AOOS)
文摘Using monthly mean sea ice velocity data obtained from the International Arctic Buoy Programme （IABP） for the period of 1979–1998 and the monthly mean NCEP/NCAR re-analysis dataset （1960–2002）, we investigated the spatiotemporal evolution of the leading sea ice motion mode （based on a complex correlation matrix constructed of normalized sea ice motion velocity） and their association with sea level pressure （SLP） and the predominant modes of surface wind field variability. The results indicate that the leading winter sea ice motion mode’s spatial evolution is characterized by two alternating and distinct sea ice modes, or their linear combination. One mode （M1） shows a nearly closed cyclonic or anti-cyclonic circulation anomaly in the Arctic Basin and its marginal seas, resembling to a large extent the response of sea ice motion to the Arctic Oscillation （AO）, as many previous studies have revealed. The other mode （M2） displays a coherent cyclonic or anti-cyclonic circulation anomaly with its center close to the Laptev Sea, which has not been identified in previous observational studies. In fact, M1 and M2 respectively reflect the responses of sea ice motion to two predominant modes of winter surface wind variability north of 70 ？ N, which well correspond, with slight differences, to the first two modes of EOF analysis of winter monthly mean SLP north of 70 ？ N. These slight differences in SLP anomalies lead to a difference of M2 from the response of sea ice motion to the dipole anomaly. Although the AO significantly influences sea ice motion, it is not crucial for the existence of M1. The new sea ice motion mode （M2） has the largest variance and clearly differs from the response of winter monthly mean sea ice motion to the dipole anomaly in SLP fields, and corresponding SLP anomalies also show differences compared to the dipole anomaly. This study indicates that in the Arctic Basin and its marginal seas, slight differences in SLP anomaly patterns can force distinctly different sea ice motion anomalies.
基金funded by the Innovation Platform for Basic Research in Breeding of Beijing, China (D08070500690801)the Science and Technology Innovation Ability Construction Projects,Beijing Academy of Agricultural and Forestry Sciences, China (KJCX20140202)
文摘Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair of varieties grown side-by-side, is time-consuming and is not suitable for the assessment of hundreds of samples. The objective of this study was to develop a procedure for the assessment of wheat variety distinctness using simple sequence repeat（SSR） markers. A comparison between the molecular and morphological profile of 797 varieties was made. On the basis of the comparison, pairs of varieties with a genetic similarity value（GSV） ≤90% were deemed to be distinct, accounting for ~85% of varieties assessed in wheat regional trials. For the remaining ~15% of varieties, GSVs between different varieties were 〉90%, among which ~35% were not distinct and the other ~65% were distinct. Therefore, if given a GSV〉90%, the pairs of varieties should be morphologically assessed in the field. To avoid any errors in the assessments, we proposed the elimination of contaminant plants from the sample before comparing the varietal genotypes, scoring of the genotype at each locus with a pair of allele numbers when constructing a molecular profile, and faithfully recording two alleles at a non-homozygous locus. To reduce the workload and cost, a three-grade markers comparison among varieties is suggested. In addition, 80 SSR markers and a technical procedure for assessment of wheat variety distinctness have been proposed. Based on the procedure, the distinctness assessment of ~85% of all wheat varieties is completed in our laboratory annually. Consequently, total field assessment has been reduced considerably.
文摘The objectives of this study were to construct a database of expressed sequence tag (EST)-simple sequence repeat (SSR) markers to identify lettuce cultivars. A set of 370 EST-SSR primer pairs were applied for fingerprinting the lettuce cultivars. Fifty-eight EST-SSR markers showed hy-per-variability and were able to differentiate 92 cultivars. A total of 176 polymorphic amplified fragments were obtained by the 58 markers, and two to eight SSR alleles were detected for each l°Cus with an average of three alleles per locus. Average polymorphism information content (PIC) was 0.425, ranging from 0.022 to 0.743. Cluster analysis was based on Jaccard’s distance coefficients using the method of unweighted pair group. In this method we used arithmetical averages (UPGMA) algorithm categorized 4 major groups, which were in accordance to morphological traits. The eight cultivars of three groups with 100% genetic similarity through SSR analysis were investigated by phenotypic traits. These cultivars including these pairs are very similar in 27 morphological characteristics. Therefore, these EST-SSR markers could be used to select similar cultivars through management of reference collection to complement distinctiveness test of lettuce cultivars.
文摘The intertidal zone is a complex coastal area exposed to a wide variety of environmental factors. During low tide, rocky pools are exposed to air for several hours throughout the day, and environmental conditions such as temperature and salinity are highly variable. Fish communities that inhabit these tide pools are also exposed to environmental variability;therefore it is important to look at fish community structure in relation to important environmental factors such as temperature, salinity and dissolved oxygen on tide pools during spring tides, time of greater exposure to air. Therefore, the aim of the present study was to analyze the variation of the taxonomic distinctness of intertidal fish communities considering temperature, salinity and dissolved oxygen of the water that remains trapped in the tide pools during low tide. Visual census surveys were carried out monthly, from January to December 2015, in the intertidal zone of El Faro during spring tides on full moon days, when fluctuations of environmental variables are significant. Total extension of the census surveys was 156 × 5 m (780 m2). A total of 145 tide pools were sampled and divided in three groups (small, medium and large) according to size and depths that ranged from 20 to 45 cm. Temperature, salinity and dissolved oxygen fluctuate throughout the year of study. Thermal difference between open ocean and tide pools ranged from 3.5°C to 4.5°C. A total of 3757 organisms from 22 species, 12 families, four orders and one class were recorded. When comparing taxonomic distinctness and average taxonomic distinctness between months and tide pools of different sizes, values fell within the confidence intervals in the tunnel and were located close to the mean.
基金supported by the National Natural Science Foundation of China(Grant Nos.11105002 and 61170172)the Natural Science Foundation of Anhui Province,China(Grant Nos.1408085QA16 and 1408085ME101)+1 种基金the China Postdoctoral Science Foundation(Grant No.2014M551788)the Open-end Fund of State Key Laboratory of Advanced Electromagnetic Engineering and Technology(HUST),China(Grant No.GZ1301)
文摘Atmospheric lower-power pulsed microwave argon cold plasma jets are obtained by using coaxial transmission line resonators in ambient air.The plasma jet plumes are generated at the end of a metal wire placed in the middle of the dielectric tubes.The electromagnetic model analyses and simulation results suggest that the discharges are excited resonantly by the enhanced electric field of surface plasmon polaritons.Moreover,for conquering the defect of atmospheric argon filamentation discharges excited by 2.45-GHz of continued microwave,the distinctive patterns of the plasma jet plumes can be maintained by applying different gas flow rates of argon gas,frequencies of pulsed modulator,duty cycles of pulsed microwave,peak values of input microwave power,and even by using different materials of dielectric tubes.In addition,the emission spectrum,the plume temperature,and other plasma parameters are measured,which shows that the proposed pulsed microwave plasma jets can be adjusted for plasma biomedical applications.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.3072020CF1019)Heilongjiang Provincial Postdoctoral Science Foundation(No.LBH-Z19137)Natural Science Foundation of Heilongjiang Province(No.LH2019E038)。
文摘New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and obviously adjusted by increased slurry temperature corresponding to change in distinctive acoustic properties.Moreover,density of all IBPIF kept at only 12-17 kg/m3.With increasing slurry temperature from 0℃to 40℃,cell size and window opening rate gradually increased from 553μm to 791μm and from 6.85%to 58.46%,respectively.In this study,IBPIF generated by slurries at 0℃(marked as PIF-2)and 40℃(marked as PIF-6)showed best and distinctive acoustic behavior in 315-800 Hz and 800-6300 Hz regions,respectively.After acoustic behavior study of combined IBPIF prepared by stitching combination between two distinctive acoustic IBPIFs,results showed that only when PIF-6 sheet used as sound receiving surface even though with thickness of only 10 mm could the combined IBPIF possess the best acoustic level in 800-6300 Hz region as PIF-6.Furtherly,acoustic behavior in 315-800 Hz region could be significantly enhanced by increasing thickness of PIF-2 and could reach or close to the best acoustic level.
文摘Brand construction plays an increasingly important role in marketing and competition in modern agricultural industry. There are problems in brand construction of tropical distinctive agricultural products in Hainan,including less famous brand products,weak core competence,strengthening declaration and ignoring management as well as imperfect marketing system,therefore resource integration should be stressed to develop famous brand products and technological innovation should be strengthened to promote core competence of enterprise.
文摘It has been claimed in the literature that impossibility of faster-than-light quantum communication has an origin of indistinguishability of ensembles with the same density matrix. We show that the two concepts are not related.We argue that even with an ideal single-atom-precision measurement, it is generally impossible to produce two ensembles with exactly the same density matrix; or to produce ensembles with the same density matrix, classical communication is necessary. Hence the impossibility of faster-than-light communication does not imply the indistinguishability of ensembles with the same density matrix.
文摘To retrofit and strengthen existing unreinforced masonry (URM) structures to resist the potential earthquake damages has become an important issue in Australia. In order to secure the performance of URM under seismic loading in the future, a research project was carried out aimed at developing a simple and high strength seismic retrofitting technique for masonry structures. A series of experimental testing on URM walls retrofitted with an innovative technique by cable system have been conducted. The results indicated that both the strength and ductility of the tested speci-mens were significantly enhanced with the technique. An analytical model which is based on Dis-tinct Element Method (DEM) has also been developed to simulate the behaviour of URM walls be-fore and after retrofitting. The model is then further developed by applying a seismic wave to the wall to simulate the wall behavior under earthquake loads before and after retrofitting.
基金Supported by 2010 Research Project of Guangxi Education Department(201010LX411)Research Project of Guangxi University of Finance and Economics(2010A01)
文摘On the basis of the developmental status of Guangxi distinctive agriculture,the key selection of developing Guangxi distinctive agriculture is analyzed.Its distinctive agriculture contains distinctive plantation,distinctive forestry and distinctive breeding.Based on the analysis,two display indices,domestic comparative advantages index and domestic competitiveness,are selected to analyze the competitiveness of Guangxi distinctive agriculture.The results show that at present the overall competitiveness of Guangxi distinctive agriculture is strong,but its competitiveness is reflected on resource advantages and most of the resources are primary agro-products.Accordingly,in the future,Guangxi distinctive agriculture should adopt non-equilibrium developmental strategy;take the great-leap-forward developmental path;apply modern production elements to increase the competitiveness of Guangxi distinctive agriculture.It should lay stress on "three innovation",which includes organization innovation,developing distinctive agricultural firms ;technology innovation,enlarging the scope and scale of agricultural listed companies;financial fund-raising innovation,transforming traditional distinctive agriculture by using high and new technology.
文摘The risks of metal compounds to human health are highlighted by the ubiquity of exposure and their persistence in the environment.Although compounds of As,Cd,Co,Cr,and Ni are known or“reasonably anticipated”to be carcinogenic to humans and/or experimental animals, the cellular targets of these health hazards and the underlying mechanisms of their carcinogenic- ity are still unclear.We show in this report that dramatic,time-and dose-dependent cytoskeletal perturbations,especially in the distribution and organization patterns of microtubules and mi- crofilaments,two of the principal components of the cytoskeleton,occurred in 3T3 cells upon exposure to these metal salts.Each metal salt appeared to induce a different,typical pattern of cytoskeletal injury,probably reflecting the specificity of action of each metal ion.These results suggest that the cytoskeleton can indeed act as a target for injury by epigenetic carcinogenic metal compounds in the environment.These findings should help our efforts to understand the mechanisms of action of metal compounds at the subcellular and molecular levels.1989 Academic Press,Inc.
文摘Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of presplitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.
