Precipitation plays a crucial role in the water cycle of Northwest China.Obtaining accurate precipitation data is crucial for regional water resource management,hydrological forecasting,flood control and drought relie...Precipitation plays a crucial role in the water cycle of Northwest China.Obtaining accurate precipitation data is crucial for regional water resource management,hydrological forecasting,flood control and drought relief.Currently,the applicability of multi-source precipitation products for long time series in Northwest China has not been thoroughly evaluated.In this study,precipitation data from 183 meteorological stations in Northwest China from 1979 to 2020 were selected to assess the regional applicability of four precipitation products(the fifth generation of European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis of the global climate(ERA5),Global Precipitation Climatology Centre(GPCC),Climatic Research Unit gridded Time Series Version 4.07(CRU TS v4.07,hereafter CRU),and Tropical Rainfall Measuring Mission(TRMM))based on the following statistical indicators:correlation coefficient,root mean square error(RMSE),relative bias(RB),mean absolute error(MAE),probability of detection(POD),false alarm ratio(FAR),and equitable threat score(ETS).The results showed that precipitation in Northwest China was generally high in the east and low in the west,and exhibited an increasing trend from 1979 to 2020.Compared with the station observations,ERA5 showed a larger spatial distribution difference than the other products.The overall overestimation of multi-year average precipitation was approximately 200.00 mm and the degree of overestimation increased with increasing precipitation intensity.The multi-year average precipitation of GPCC and CRU was relatively close to that of station observations.The trend of annual precipitation of TRMM was overestimated in high-altitude regions and the eastern part of Lanzhou with more precipitation.At the monthly scale,GPCC performed well but underestimated precipitation in the Tarim Basin(RB=-4.11%),while ERA5 and TRMM exhibited poor accuracy in high-altitude regions.ERA5 had a large bias(RB≥120.00%)in winter months and a strong dispersion(RMSE≥35.00 mm)in summer months.TRMM showed a relatively low correlation with station observations in winter months(correlation coefficients≤0.70).The capture performance analysis showed that ERA5,GPCC,and TRMM had lower POD and ETS values and higher FAR values in Northwest China as the precipitation intensity increased.ERA5 showed a high capture performance for small precipitation events and a slower decreasing trend of POD as the precipitation intensity increased.GPCC had the lowest FAR values.TRMM was statistically ineffective for predicting the occurrence of daily precipitation events.The findings provide a reference for data users to select appropriate datasets in Northwest China and for data developers to develop new precipitation products in the future.展开更多
This research takes China-aided construction projects in Asia since the Belt and Road Initiative as examples to explore the applicability of Chinese architectural design standards in other Asian countries.So far,the s...This research takes China-aided construction projects in Asia since the Belt and Road Initiative as examples to explore the applicability of Chinese architectural design standards in other Asian countries.So far,the standards demonstrated the highest applicability in South Asia is the best followed by Southeast Asia.Chinese architectural design standards for educational buildings showed the highest applicability,followed by office,medical,and sports buildings.This study puts forward some strategies to improve the applicability of Chinese architectural design standards.These strategies include integrating regionalism and local cultural traditions,optimizing energy efficiency,and aligning designs with local usage habits.This study serves as a reference for similar projects in the future.展开更多
The complexity and applicability of three relative car-following models are investigated and they are the optimal velocity model (OVM),the generalized force model (GFM) and the full velocity difference model (FVD...The complexity and applicability of three relative car-following models are investigated and they are the optimal velocity model (OVM),the generalized force model (GFM) and the full velocity difference model (FVDM).The vehicle trajectory data used is collected from the digital pictures obtained at a 30-storey building near Ⅰ-80 freeway.Three different calibrating methods are used to estimate the model parameters and to study the relationships between model complexity and applicability from overall,inter-driver and intra-driver analysis.Results of the three methods of the OVM,GFM and FVDM show that the complexity and applicability are not consistent and the complicated models are not always superior to the simple ones in modeling car-following.The findings of this study can provide useful information for car-following behavior modeling.展开更多
Erigerontis Herba(EH),the dried whole plant of Erigeron breviscapus,is well-known for circulating blood,activating meridians to alleviate pain,expelling wind,and clearing away cold.It has been extensively utilized in ...Erigerontis Herba(EH),the dried whole plant of Erigeron breviscapus,is well-known for circulating blood,activating meridians to alleviate pain,expelling wind,and clearing away cold.It has been extensively utilized in southern China for the treatment of stroke hemiplegia,chest stuffiness and pains,rheumatic arthralgia,headache,and toothache.This review focuses on the botany,ethnopharmacology,phytochemistry,pharmacology and toxicity of EH and its related prescriptions to offer new insights for prospective research of EH.Relevant information about EH was retrieved from ancient records and books,PubMed,China National Knowledge Infrastructure,Chinese Pharmacopoeia,Web of Science,Doctoral and Master’s Theses,and various electronic databases.EH is a member of Compositae family and is mainly grown in southern China.Traditional Chinese medicine records that EH has the effects of circulating blood and removing blood stasis,expelling wind,and removing cold,as well as relieving rigidity of muscle and relieving pain.By now,nearly 200 ingredients have been characterized from EH,including flavonoids,caffeoyls,aromatic acids,coumarins,pentacyclic terpenoids,volatile oil and other compounds.EH extracts,EH related prescriptions(Dengzhan Xixin injection,Dengzhan Shengmai capsules,etc.)or compounds(scutellarin,scutellarein,etc.)possessed obvious therapeutic effects of ischemic stroke,cerebral hemorrhage,myocardial infarction,Alzheimer’s disease,diabetes and its complications,gastric cancer,bone,and joint degenerative diseases.Scutellarin,the major active compound of EH,has been used as a quality marker.And no obvious toxicity of EH has been reported.According to its traditional applications,ethnopharmacology,phytochemistry,pharmacology,and toxicity,EH was applied as a valuable herb for clinical application in food and medicine fields.While several compounds have been shown to possess diverse biological activities,the underlying mechanisms of their actions remain elusive.To fully exploit the medicinal potential of EH,further studies on understanding the effective material basis and mechanisms are warranted.展开更多
Graphene,as star versatile materials having extraordinarily high electric conductivity,electron mobility,thermal conductivity,thermal stability,optical transparency,and mechanical strength,has attracted much attention...Graphene,as star versatile materials having extraordinarily high electric conductivity,electron mobility,thermal conductivity,thermal stability,optical transparency,and mechanical strength,has attracted much attention from scientists and engineers in the field of materials,chemistry,physics,energy,and environment in the last decade and achieved fruitful accomplishment.This review discusses preparation strategies,functionality,characterization,and applications for two dimensional nanosheet and quasi-onedimensional nanoribbon of graphene through direct exfoliation of graphite,chemical vapor deposition of hydrocarbon,laser-induced direct synthesis of graphene,laser etched graphene oxide in the dry state without the use of toxic reducing agent hydrazine,unzipping carbon nanotube,and polycondensation of polycyclic aromatics on the basis of 178 representative references mostly in 2015.The stabilization of graphene oxide prepared in chemical preparation in " top-down" is emphasized.Several vital classic methods of characterizing molecular structure,C/O ratio,defect,morphology,single-or few-layered( 2 to 10 layers) structure,porous and hollow structures,including Raman spectroscopy,AFM,SEM,TEM,STM,electron diffraction,X-ray diffraction,and X-ray photoelectron spectroscopy are systematically introduced.Because graphene possesses novel incomparable multifunctionalities,its versatile applications as novel conducting additives,reinforcing filler,separation membrane,sensor,anticorrosive coating,catalyst,electromagnetic shield,lubricant,and flexible electrode materials in electrochemical and electronic devices,including photovoltaic cells,supercapacitors,rechargeable batteries,sensors,field effect transistors,light emitting diodes,separation membranes,adsorbents and absorbents,catalysts,electro-optic modulator,terahertz emitter and detector,and semiconductors,have been mentioned.Especially in the aspect of both high performance and cost-effectiveness,graphene is expected to be even superior to the expensive carbon nanotubes.展开更多
Gradation equation is one way to describe the gradation of coarse-grained soil conveniently,exactly and quantitatively.With the gradation equation,the influence of gradation on the mechanical behaviors of coarse-grain...Gradation equation is one way to describe the gradation of coarse-grained soil conveniently,exactly and quantitatively.With the gradation equation,the influence of gradation on the mechanical behaviors of coarse-grained soil can be expressed quantitatively.A new gradation equation with a parameter is proposed.The basic properties and applicability of the new equation are studied.The results show that the proposed equation has the applicability to express coarse-grained soil gradation(CSG),and the range of the parameter β is found to be 0<β<1.The value ofbdetermines the gradation curve shape.If β>0.5,the gradation curve is sigmoidal,otherwise the gradation curve is hyperbolic.For well graded gradations,the parameter has the value of 0.13<β<1.Several CSGs used in domestic and foreign earth-rockfill dams are probed,and the value of the parameterbfalls in the range of 0.18 to 0.97.The investigation of the range of β is of value to guide the design for CSG of earth-rockfill dam.展开更多
In this paper, we took the lead in studying on specificity of the microsatellite DNA loci and applicability of mi crosatellite DNA primers in protozoa. In order to study characters of microsatellites in free living pr...In this paper, we took the lead in studying on specificity of the microsatellite DNA loci and applicability of mi crosatellite DNA primers in protozoa. In order to study characters of microsatellites in free living protozoa, eight microsatellite loci primers developed from Trypanosoma cruzi (MCLE01, SCLE10, MCLE08, SCLE11, MCLF10, MCLG10, MCL03, MCL05) were employed to amplify microsatellite in four free living protozoa, including Bodo designis, Euglena gracilis FACHB848, Paramecium bruzise and Tetrahymena thermophila BF1. In the amplification systems of P. bruzise, four loci (SCLE10, SCLE11, MCLF10, MCL03) were amplified successfully, and four amplification fragments were in proper size. In genome of E. gracilis FACHB848, five of eight primers brought five clear amplification bands. In B. designis, three (No.4, 5 and 7) of eight loci produced clear and sharp products without stutter bands, whereas no bands appeared in T. thermophila BF1. Further, eight 300-500 bp amplification fragments were cloned and sequenced. Nevertheless, all sequenced products did not contain corresponding microsatellite sequence, although Bodo is in the same order and has the nearest phylogenetic relation with Trypanosoma among these four species. Thus, the microsatellite DNA primers can not be applied among order or more far taxa, and the specificity of microsatellite DNA is very high in protozoa. The results of this study will contribute to our understanding of microsatellite DNA in protozoa.展开更多
Friedberg, Lee and Zhao (FLZ) proposed a method for effectively evaluating the eigenenergies and eigen wavefunctions of quantum systems. In this work, we study several special cases to investigate applicability of the...Friedberg, Lee and Zhao (FLZ) proposed a method for effectively evaluating the eigenenergies and eigen wavefunctions of quantum systems. In this work, we study several special cases to investigate applicability of the method.Concretely, we calculate the ground-state eigenenergy of the Hellmann potential as well as the Cornell potential, and also evaluate the energies of the systems where linear term is added to the Coulomb as a perturbation. The results obtained in this method have a surprising agreement with the traditional method or the numerical results. Since the results in this method have obvious analyticity compared to that in other methods, and because of the simplicity for calculations this method can be applied to solving the Schrodinger equation and provides us a better understanding of the physical essence of the concerned systems. But meanwhile applications of the FLZ method are restricted at present, especially for certain potential forms, but due to its obvious advantages, it should be further developed.展开更多
A recent paper by C.H.Henry and D.V.Lang claims that the adiabatic approximation breaks down in the neighborhood of the intersection of the adiabatic potential curves for the two electronic states,between which multip...A recent paper by C.H.Henry and D.V.Lang claims that the adiabatic approximation breaks down in the neighborhood of the intersection of the adiabatic potential curves for the two electronic states,between which multiphonon transitions occur.It is shown that their claim is not justified;what they consider to be the sign of failure of the adiabatic approximation is no more than an indication of the fact that owing to the uncertainty principle,there is a finite neighborhood around the above mentioned point of intersection,throughout which multi-phonon transitions can occur.Direct calculation of the multi-phonon transition probability on the basis of the adiabatic approximation gives in fact a result identical with the result obtained with their version of the theory.Further discussions contend that in more general situations Henry and Lang's formulation of the theory will no longer be applicable and a proper adiabatic approximation treatment by first lifting the degeneracy at the intersection point will be necessary.展开更多
Seismometer self-noise levels were determined using Sleeman’s three-sensor method in combination with the Welch method for different parameter combinations. The self-noise levels decreased with the increasing segment...Seismometer self-noise levels were determined using Sleeman’s three-sensor method in combination with the Welch method for different parameter combinations. The self-noise levels decreased with the increasing segment window length, which is equivalent to the subwindow length, and with the increasing segment overlap rate for different frequency points at a fixed band. After the statistical examination of 9800 different parameter combinations, a zone of reasonable self-noise calculation parameter combinations was identified. Reasons for the unsuitability of certain parameter combinations were explored with respect to their distortion of the seismometer’s self-noise levels.展开更多
Applicability of public rental housing was analyzed from the perspectives of site selection, tenant and indoor environment. Special needs of seniors and the physically disabled, in particular, were taken into consider...Applicability of public rental housing was analyzed from the perspectives of site selection, tenant and indoor environment. Special needs of seniors and the physically disabled, in particular, were taken into consideration, indoor barrier-free designs were analyzed to further improve applicability of public rental housing.展开更多
In order to effectively use the ERA5 reanalysis data,observation data in and around Guangdong Province was used to evaluate the reanalysis data by analyzing the correlation coefficient and deviation. The results showe...In order to effectively use the ERA5 reanalysis data,observation data in and around Guangdong Province was used to evaluate the reanalysis data by analyzing the correlation coefficient and deviation. The results showed that among the surface elements,the sea level pressure and air temperature performed the best reproducibility,second the relative humidity and wind speed,and they had better performance in the Pearl River Delta and its surrounding areas,while the worst was wind direction. Except the relative humidity,elements had better performance at higher levels than lower levels among the ERA5 reanalysis upper-air data.展开更多
背景:梯度人工骨修复支架模拟了骨骼系统中的独特特征,在骨骼系统再生中具有巨大的应用潜力。目的:综述梯度人工骨修复支架在骨骼系统组织工程中的最新研究进展,并阐述了其优势与制造策略。方法:由第一作者检索Web of Science和PubMed...背景:梯度人工骨修复支架模拟了骨骼系统中的独特特征,在骨骼系统再生中具有巨大的应用潜力。目的:综述梯度人工骨修复支架在骨骼系统组织工程中的最新研究进展,并阐述了其优势与制造策略。方法:由第一作者检索Web of Science和PubMed数据库2000-2023年发表的文献,英文检索词为“gradient,bone regeneration,scaffold”,最终筛选后对76篇文献进行分析总结。结果与结论:①作为骨骼系统组织高效、高质量修复的重要手段,梯度人工骨修复支架目前针对骨组织、骨-软骨、肌腱-骨组织的天然梯度特征进行了仿生设计,这些支架能够一定程度地从结构、成分上模拟原生组织的细胞外基质,从而促进细胞黏附、迁移、增殖和分化,促进受损组织向原生状态再生恢复。②先进制造技术为梯度人工骨修复支架制备提供了更多可能;目前已经开发了通过空间差异化纤维排布和生物活性物质加载构建的梯度电纺纤维支架;分层叠加、分级孔隙率与生物3D打印技术制造的梯度3D打印支架;原位分层注射、简单逐层叠加、冷冻干燥法制造的梯度水凝胶支架;另外还包括其他方式或多方法联用的支架;这些支架在体外实验中展示了良好的生物相容性,在小型动物实验中能够加速组织再生并且观察到组织学结构明显改善。③目前开发的梯度人工骨修复支架仍需进一步优化,提高在梯度尺度上的匹配性,进一步明确材料与组织相互作用,避免降解产物导致的副反应等问题,未来需要结合相关学科优势与临床需求进一步优化。展开更多
基金supported by the National Key Research and Development Program of China(2023YFC3206300)the National Natural Science Foundation of China(42477529,42371145,42261026)+2 种基金the China-Pakistan Joint Program of the Chinese Academy of Sciences(046GJHZ2023069MI)the Gansu Provincial Science and Technology Program(22ZD6FA005)the National Cryosphere Desert Data Center(E01Z790201).
文摘Precipitation plays a crucial role in the water cycle of Northwest China.Obtaining accurate precipitation data is crucial for regional water resource management,hydrological forecasting,flood control and drought relief.Currently,the applicability of multi-source precipitation products for long time series in Northwest China has not been thoroughly evaluated.In this study,precipitation data from 183 meteorological stations in Northwest China from 1979 to 2020 were selected to assess the regional applicability of four precipitation products(the fifth generation of European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis of the global climate(ERA5),Global Precipitation Climatology Centre(GPCC),Climatic Research Unit gridded Time Series Version 4.07(CRU TS v4.07,hereafter CRU),and Tropical Rainfall Measuring Mission(TRMM))based on the following statistical indicators:correlation coefficient,root mean square error(RMSE),relative bias(RB),mean absolute error(MAE),probability of detection(POD),false alarm ratio(FAR),and equitable threat score(ETS).The results showed that precipitation in Northwest China was generally high in the east and low in the west,and exhibited an increasing trend from 1979 to 2020.Compared with the station observations,ERA5 showed a larger spatial distribution difference than the other products.The overall overestimation of multi-year average precipitation was approximately 200.00 mm and the degree of overestimation increased with increasing precipitation intensity.The multi-year average precipitation of GPCC and CRU was relatively close to that of station observations.The trend of annual precipitation of TRMM was overestimated in high-altitude regions and the eastern part of Lanzhou with more precipitation.At the monthly scale,GPCC performed well but underestimated precipitation in the Tarim Basin(RB=-4.11%),while ERA5 and TRMM exhibited poor accuracy in high-altitude regions.ERA5 had a large bias(RB≥120.00%)in winter months and a strong dispersion(RMSE≥35.00 mm)in summer months.TRMM showed a relatively low correlation with station observations in winter months(correlation coefficients≤0.70).The capture performance analysis showed that ERA5,GPCC,and TRMM had lower POD and ETS values and higher FAR values in Northwest China as the precipitation intensity increased.ERA5 showed a high capture performance for small precipitation events and a slower decreasing trend of POD as the precipitation intensity increased.GPCC had the lowest FAR values.TRMM was statistically ineffective for predicting the occurrence of daily precipitation events.The findings provide a reference for data users to select appropriate datasets in Northwest China and for data developers to develop new precipitation products in the future.
基金Humanities and Social Science Research Project of Colleges and Universities in Hebei Province(BJS2022039)2022 Annual Project of Education Science Research 14th“Five-Year”Plan in Hebei Province(2203094)+1 种基金2017 New Engineering Research and Practice Project of Hebei Colleges and Universities(2017GJXGK041)Doctoral Fund of Tangshan Normal University(2022A04)。
文摘This research takes China-aided construction projects in Asia since the Belt and Road Initiative as examples to explore the applicability of Chinese architectural design standards in other Asian countries.So far,the standards demonstrated the highest applicability in South Asia is the best followed by Southeast Asia.Chinese architectural design standards for educational buildings showed the highest applicability,followed by office,medical,and sports buildings.This study puts forward some strategies to improve the applicability of Chinese architectural design standards.These strategies include integrating regionalism and local cultural traditions,optimizing energy efficiency,and aligning designs with local usage habits.This study serves as a reference for similar projects in the future.
基金The National Basic Research Program of China(973Program)(No.2012CB725402)the National Natural Science Foundation of China(No.51478113)
文摘The complexity and applicability of three relative car-following models are investigated and they are the optimal velocity model (OVM),the generalized force model (GFM) and the full velocity difference model (FVDM).The vehicle trajectory data used is collected from the digital pictures obtained at a 30-storey building near Ⅰ-80 freeway.Three different calibrating methods are used to estimate the model parameters and to study the relationships between model complexity and applicability from overall,inter-driver and intra-driver analysis.Results of the three methods of the OVM,GFM and FVDM show that the complexity and applicability are not consistent and the complicated models are not always superior to the simple ones in modeling car-following.The findings of this study can provide useful information for car-following behavior modeling.
基金funded by the State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources(Guangxi Normal University)(CMEMR2022-B11)the Natural Science Research of Jiangsu Higher education Institution of China(22KJB360018)Jiangsu Province University Student Innovation and Entrepreneurial Training Program(202311117019Z).
文摘Erigerontis Herba(EH),the dried whole plant of Erigeron breviscapus,is well-known for circulating blood,activating meridians to alleviate pain,expelling wind,and clearing away cold.It has been extensively utilized in southern China for the treatment of stroke hemiplegia,chest stuffiness and pains,rheumatic arthralgia,headache,and toothache.This review focuses on the botany,ethnopharmacology,phytochemistry,pharmacology and toxicity of EH and its related prescriptions to offer new insights for prospective research of EH.Relevant information about EH was retrieved from ancient records and books,PubMed,China National Knowledge Infrastructure,Chinese Pharmacopoeia,Web of Science,Doctoral and Master’s Theses,and various electronic databases.EH is a member of Compositae family and is mainly grown in southern China.Traditional Chinese medicine records that EH has the effects of circulating blood and removing blood stasis,expelling wind,and removing cold,as well as relieving rigidity of muscle and relieving pain.By now,nearly 200 ingredients have been characterized from EH,including flavonoids,caffeoyls,aromatic acids,coumarins,pentacyclic terpenoids,volatile oil and other compounds.EH extracts,EH related prescriptions(Dengzhan Xixin injection,Dengzhan Shengmai capsules,etc.)or compounds(scutellarin,scutellarein,etc.)possessed obvious therapeutic effects of ischemic stroke,cerebral hemorrhage,myocardial infarction,Alzheimer’s disease,diabetes and its complications,gastric cancer,bone,and joint degenerative diseases.Scutellarin,the major active compound of EH,has been used as a quality marker.And no obvious toxicity of EH has been reported.According to its traditional applications,ethnopharmacology,phytochemistry,pharmacology,and toxicity,EH was applied as a valuable herb for clinical application in food and medicine fields.While several compounds have been shown to possess diverse biological activities,the underlying mechanisms of their actions remain elusive.To fully exploit the medicinal potential of EH,further studies on understanding the effective material basis and mechanisms are warranted.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51273148)the Foundation of State Key Laboratory of Pollution Control and Resource Reuse(Tongji University),China(Grant No.PCRRY14003)
文摘Graphene,as star versatile materials having extraordinarily high electric conductivity,electron mobility,thermal conductivity,thermal stability,optical transparency,and mechanical strength,has attracted much attention from scientists and engineers in the field of materials,chemistry,physics,energy,and environment in the last decade and achieved fruitful accomplishment.This review discusses preparation strategies,functionality,characterization,and applications for two dimensional nanosheet and quasi-onedimensional nanoribbon of graphene through direct exfoliation of graphite,chemical vapor deposition of hydrocarbon,laser-induced direct synthesis of graphene,laser etched graphene oxide in the dry state without the use of toxic reducing agent hydrazine,unzipping carbon nanotube,and polycondensation of polycyclic aromatics on the basis of 178 representative references mostly in 2015.The stabilization of graphene oxide prepared in chemical preparation in " top-down" is emphasized.Several vital classic methods of characterizing molecular structure,C/O ratio,defect,morphology,single-or few-layered( 2 to 10 layers) structure,porous and hollow structures,including Raman spectroscopy,AFM,SEM,TEM,STM,electron diffraction,X-ray diffraction,and X-ray photoelectron spectroscopy are systematically introduced.Because graphene possesses novel incomparable multifunctionalities,its versatile applications as novel conducting additives,reinforcing filler,separation membrane,sensor,anticorrosive coating,catalyst,electromagnetic shield,lubricant,and flexible electrode materials in electrochemical and electronic devices,including photovoltaic cells,supercapacitors,rechargeable batteries,sensors,field effect transistors,light emitting diodes,separation membranes,adsorbents and absorbents,catalysts,electro-optic modulator,terahertz emitter and detector,and semiconductors,have been mentioned.Especially in the aspect of both high performance and cost-effectiveness,graphene is expected to be even superior to the expensive carbon nanotubes.
基金Project(2018YFC1508505)supported by the National Key Research and Development Program of ChinaProject(U1865104)supported by Yalong River Joint Fund of Natural Science Foundation of China-Yalong River Basin Hydropower Development Co.,Ltd.,China+1 种基金Project(51479052)supported by National Natural Science of ChinaProject(2019T120443)supported by China Postdoctoral Science Foundation。
文摘Gradation equation is one way to describe the gradation of coarse-grained soil conveniently,exactly and quantitatively.With the gradation equation,the influence of gradation on the mechanical behaviors of coarse-grained soil can be expressed quantitatively.A new gradation equation with a parameter is proposed.The basic properties and applicability of the new equation are studied.The results show that the proposed equation has the applicability to express coarse-grained soil gradation(CSG),and the range of the parameter β is found to be 0<β<1.The value ofbdetermines the gradation curve shape.If β>0.5,the gradation curve is sigmoidal,otherwise the gradation curve is hyperbolic.For well graded gradations,the parameter has the value of 0.13<β<1.Several CSGs used in domestic and foreign earth-rockfill dams are probed,and the value of the parameterbfalls in the range of 0.18 to 0.97.The investigation of the range of β is of value to guide the design for CSG of earth-rockfill dam.
基金supported financially by the Frontier Science Projects Programme of the Institute of Hydrobiology,the Chinese Academy of Sciences(No.220207)
文摘In this paper, we took the lead in studying on specificity of the microsatellite DNA loci and applicability of mi crosatellite DNA primers in protozoa. In order to study characters of microsatellites in free living protozoa, eight microsatellite loci primers developed from Trypanosoma cruzi (MCLE01, SCLE10, MCLE08, SCLE11, MCLF10, MCLG10, MCL03, MCL05) were employed to amplify microsatellite in four free living protozoa, including Bodo designis, Euglena gracilis FACHB848, Paramecium bruzise and Tetrahymena thermophila BF1. In the amplification systems of P. bruzise, four loci (SCLE10, SCLE11, MCLF10, MCL03) were amplified successfully, and four amplification fragments were in proper size. In genome of E. gracilis FACHB848, five of eight primers brought five clear amplification bands. In B. designis, three (No.4, 5 and 7) of eight loci produced clear and sharp products without stutter bands, whereas no bands appeared in T. thermophila BF1. Further, eight 300-500 bp amplification fragments were cloned and sequenced. Nevertheless, all sequenced products did not contain corresponding microsatellite sequence, although Bodo is in the same order and has the nearest phylogenetic relation with Trypanosoma among these four species. Thus, the microsatellite DNA primers can not be applied among order or more far taxa, and the specificity of microsatellite DNA is very high in protozoa. The results of this study will contribute to our understanding of microsatellite DNA in protozoa.
文摘Friedberg, Lee and Zhao (FLZ) proposed a method for effectively evaluating the eigenenergies and eigen wavefunctions of quantum systems. In this work, we study several special cases to investigate applicability of the method.Concretely, we calculate the ground-state eigenenergy of the Hellmann potential as well as the Cornell potential, and also evaluate the energies of the systems where linear term is added to the Coulomb as a perturbation. The results obtained in this method have a surprising agreement with the traditional method or the numerical results. Since the results in this method have obvious analyticity compared to that in other methods, and because of the simplicity for calculations this method can be applied to solving the Schrodinger equation and provides us a better understanding of the physical essence of the concerned systems. But meanwhile applications of the FLZ method are restricted at present, especially for certain potential forms, but due to its obvious advantages, it should be further developed.
文摘A recent paper by C.H.Henry and D.V.Lang claims that the adiabatic approximation breaks down in the neighborhood of the intersection of the adiabatic potential curves for the two electronic states,between which multiphonon transitions occur.It is shown that their claim is not justified;what they consider to be the sign of failure of the adiabatic approximation is no more than an indication of the fact that owing to the uncertainty principle,there is a finite neighborhood around the above mentioned point of intersection,throughout which multi-phonon transitions can occur.Direct calculation of the multi-phonon transition probability on the basis of the adiabatic approximation gives in fact a result identical with the result obtained with their version of the theory.Further discussions contend that in more general situations Henry and Lang's formulation of the theory will no longer be applicable and a proper adiabatic approximation treatment by first lifting the degeneracy at the intersection point will be necessary.
基金supported by Study on Seismograph Calibration and Preparation of Draft International Standard (201408005)the Earthquake Science and technology Program of Hebei Province (201303)Special Program for Earthquake monitoring (20130203)
文摘Seismometer self-noise levels were determined using Sleeman’s three-sensor method in combination with the Welch method for different parameter combinations. The self-noise levels decreased with the increasing segment window length, which is equivalent to the subwindow length, and with the increasing segment overlap rate for different frequency points at a fixed band. After the statistical examination of 9800 different parameter combinations, a zone of reasonable self-noise calculation parameter combinations was identified. Reasons for the unsuitability of certain parameter combinations were explored with respect to their distortion of the seismometer’s self-noise levels.
基金Supported by Soft Science Program of Jiangxi Provincial Department of Science and Technology(2010DR00702)
文摘Applicability of public rental housing was analyzed from the perspectives of site selection, tenant and indoor environment. Special needs of seniors and the physically disabled, in particular, were taken into consideration, indoor barrier-free designs were analyzed to further improve applicability of public rental housing.
基金Supported by the Science and Technology Research Project of Guangdong Meteorological Service(GRMC2018M17)。
文摘In order to effectively use the ERA5 reanalysis data,observation data in and around Guangdong Province was used to evaluate the reanalysis data by analyzing the correlation coefficient and deviation. The results showed that among the surface elements,the sea level pressure and air temperature performed the best reproducibility,second the relative humidity and wind speed,and they had better performance in the Pearl River Delta and its surrounding areas,while the worst was wind direction. Except the relative humidity,elements had better performance at higher levels than lower levels among the ERA5 reanalysis upper-air data.
文摘背景:梯度人工骨修复支架模拟了骨骼系统中的独特特征,在骨骼系统再生中具有巨大的应用潜力。目的:综述梯度人工骨修复支架在骨骼系统组织工程中的最新研究进展,并阐述了其优势与制造策略。方法:由第一作者检索Web of Science和PubMed数据库2000-2023年发表的文献,英文检索词为“gradient,bone regeneration,scaffold”,最终筛选后对76篇文献进行分析总结。结果与结论:①作为骨骼系统组织高效、高质量修复的重要手段,梯度人工骨修复支架目前针对骨组织、骨-软骨、肌腱-骨组织的天然梯度特征进行了仿生设计,这些支架能够一定程度地从结构、成分上模拟原生组织的细胞外基质,从而促进细胞黏附、迁移、增殖和分化,促进受损组织向原生状态再生恢复。②先进制造技术为梯度人工骨修复支架制备提供了更多可能;目前已经开发了通过空间差异化纤维排布和生物活性物质加载构建的梯度电纺纤维支架;分层叠加、分级孔隙率与生物3D打印技术制造的梯度3D打印支架;原位分层注射、简单逐层叠加、冷冻干燥法制造的梯度水凝胶支架;另外还包括其他方式或多方法联用的支架;这些支架在体外实验中展示了良好的生物相容性,在小型动物实验中能够加速组织再生并且观察到组织学结构明显改善。③目前开发的梯度人工骨修复支架仍需进一步优化,提高在梯度尺度上的匹配性,进一步明确材料与组织相互作用,避免降解产物导致的副反应等问题,未来需要结合相关学科优势与临床需求进一步优化。