The optimization of methods for the quantitative evaluation of risks in drilling engineering is an effective means to ensure safety in situations where high temperature and high pressure blocks are considered.In such ...The optimization of methods for the quantitative evaluation of risks in drilling engineering is an effective means to ensure safety in situations where high temperature and high pressure blocks are considered.In such a context,this study analyzes the complexity of the drilled wells in such blocks.It is shown that phenomena such as well kick,loss,circulation,and sticking,are related to the imbalance of wellbore pressure.A method for risk quantitative evaluation is proposed accordingly.The method is used to evaluate the risk for 9 drilled wells.By comparing the predictions of the method with actual historical data related to these wells,it is found that the coincidence rate is about 95%.展开更多
Chinese domestic legislation on the judicial applicability of international treaties has been unsettled,especially under the Civil Code,which is silent on this issue.However,previous studies have depicted an image of ...Chinese domestic legislation on the judicial applicability of international treaties has been unsettled,especially under the Civil Code,which is silent on this issue.However,previous studies have depicted an image of a“pro-CISG”attitude in Chinese legal practice,which is distinguished from the tendency to circumvent the CISG in other jurisdictions such as the U.S.This contradictory phenomenon,namely the absence of guiding norms versus the embracement of the CISG in judicial practice,is rarely discussed,especially within the context of civil codification and recent external economic challenges.To verify this paradox,a manually collected dataset of 223 court decisions from 2013 to 2023 identifies some basic characteristics of the CISG judicial applicability in China,including the application rate,legal reasoning paths,citation frequencies of specific provisions,and some qualitative observations about the judicial behaviors in the international sales dispute resolution.The main finding is that Chinese courts have been applying the CISG at an obviously higher rate,compared with both their foreign counterparts and the general rate of applying foreign law in the international civil and commercial litigations in China.To explain this gap between“law in book”and“law in action,”the context of Chinese judicial practice should be considered.Despite the vagueness of domestic legislation,the judicial policy promotion,the innovative guiding cases system,the legal transplantation,and other factors may contribute to the“pro-CISG”attitude.As for the future promotion of CISG in the Chinese style of international commercial dispute resolution,these factors may coordinate with the legislative improvements.展开更多
[Objectives]This study was conducted to establish a microbial limit test method for Qingyan Zhisou Powder.[Methods]Applicability tests were carried out according to Microbial Limit Tests of Non-sterile Products,Genera...[Objectives]This study was conducted to establish a microbial limit test method for Qingyan Zhisou Powder.[Methods]Applicability tests were carried out according to Microbial Limit Tests of Non-sterile Products,General Rules 1105-1107 of Part IV of Chinese Pharmacopoeia,2020.[Results]Qingyan Zhisou Powder had a strong bacteriostatic effect on Pseudomonas aeruginosa.After increasing the dilution ratio(1:40),the bacteriostatic effect was obviously eliminated.When the total number of aerobic microbes was determined by the test liquid dilution method(1:40),the recovery values were in the range of 50%-200%;and when using the test liquid(1:10)to determine the total number of mold and yeasts,the recovery ranged from 50%to 200%.Escherichia coli,Salmonella and bile-tolerant Gram-negative bacteria were detected by both the routine method and dilution method in experimental groups.[Conclusions]The microbial limit test of Qingyan Zhisou Powder adopted the test liquid dilution method,and the routine method could be used for the test of Escherichia coli,Salmonella and bile-tolerant Gram-negative bacteria.The applicability test of the method is feasible,with scientific and accurate results,and the method can effectively control the quality of the preparation and is recommended for popularization.展开更多
In order to understand the travel characteristics and behavior patterns of women in Wangjing area and explore whether the existing situation can meet women's needs for the use of street space,the area around Wangj...In order to understand the travel characteristics and behavior patterns of women in Wangjing area and explore whether the existing situation can meet women's needs for the use of street space,the area around Wangjing South Station of Metro Line 14 was taken as an example for analysis and research.Wangjing area was classified to the following six use attributes:company enterprise,transportation hub,education and culture,residential area,municipal facilities,leisure and entertainment.The proportion of each use attribute was evaluated according to four levels:A 25%and above(including 25%),B 15%-25%,C 15%-5%,D 5%and below(including 5%).Finally,whether the plot had composite functions was judged,and the spatio-temporal laws and behavior patterns of surrounding women were analyzed from the perspectives of time and space.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 segm...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
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
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
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
The applicability of Tropical Rainfall Measuring Mission (TRMM3B42V7) precipitation data in the region was evaluated using the measured daily precipitation data in 16 hydrological stations in Shaanxi Province from 199...The applicability of Tropical Rainfall Measuring Mission (TRMM3B42V7) precipitation data in the region was evaluated using the measured daily precipitation data in 16 hydrological stations in Shaanxi Province from 1998 to 2014. The evaluation process with several statistical error metrics was applied to daily, monthly, and annual timescale. The results show that the satellite and gauge stations show good consistency for monthly and annual timescale, but rather worse accuracy of daily timescale. All timescales produced the overestimated result of average precipitation measurement. The spatially statistical distribution shows a slight correlation between the observation and satellite estimation, especially at the higher elevation area such as Taibai. The TRMM precipitation value is closer to the gauge station precipitation value at a place with lower elevation, whether the timescale is daily, monthly or annual. At the same time, the smaller timescale leads to closer relations between elevation and metrics. The research results are important value of the research study of meteorological process in the Qinba mountain area.展开更多
Due to the exhaustion of IPv4 address resources, the transition from IPv4 to IPv6 is inevitable and fairly urgent. Numerous transition mechanisms have been proposed to solve challenging issues of IPv6 transition. An i...Due to the exhaustion of IPv4 address resources, the transition from IPv4 to IPv6 is inevitable and fairly urgent. Numerous transition mechanisms have been proposed to solve challenging issues of IPv6 transition. An inter-connection between IPv4 and IPv6 networks or hosts requirement has been happening throughout the IPv6 transition process. And one-time translation scheme is indispensable to achieve the inter-connection. In addition, double translation can be used in the IPv4-IPv6-IPv4 scenario. As a long-term strategy, translation scheme is important and inevitable. However, because of the diverse characteristics and transition requirements of practical networks and the lack of applicability analysis, the selection and deployment of transition mechanisms are facing with grand challenges. Targeting at those challenges, this paper investigates the basic issues and key elements of IPv6 translation transition mechanisms, and presents its first applicability index system. In particular, we analyze the applicability of existing proposed translation techniques based on the presented index system, which has significant guidance in the practical deployment of IPv6 transition techniques.展开更多
Lakes are an important component of the earth climate system. They play an important role in the study of basin weather forecasting, air quality forecasting, and regional climate research. The accuracy of driving vari...Lakes are an important component of the earth climate system. They play an important role in the study of basin weather forecasting, air quality forecasting, and regional climate research. The accuracy of driving variables is the basic premise to ensure the rationality of lake mode simulation. Based on the in-situ observations at Bifenggang site of the Lake Taihu Eddy flux Network from 2012 to 2017, this paper investigated temporal variations in temperature, relative humidity, wind speed, radiation components at different time scales (hourly, seasonal and interannual). ERA5 reanalysis data were compared with in-situ observation to quantify the error and evaluate the performance of reanalysis data. The results show that: 1) On the hourly scale, the ERA5 reanalysis data described air temperature, and downward long-wave radiation more accurately. 2) On the seasonal variation scale, the ERA5 reanalysis data described air temperature, and downward long-wave radiation more accurately. However, the descriptions of wind speed, relative humidity and downward short-wave have large deviations. 3) On the interannual scale, the ERA5 reanalysis data show a good performance for temperature, followed by downward longwave radiation, downward shortwave radiation and relative humidity.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
Brown and Levinson's face theory is a theory of interpersonal relationship. It has successfully explained the influence of "face"in people's daily communications. The theory is built on the basis of ...Brown and Levinson's face theory is a theory of interpersonal relationship. It has successfully explained the influence of "face"in people's daily communications. The theory is built on the basis of western culture and ignores the cultural difference of "face"in China. It is not free from limitations the absoluteness of which exerts a checking effort on its universal applicability. This paper probes from the perspective of the influence of context and culture that the application of Face-Saving theory in actual communications in China, especially from those restrictions on the use of negative face in China.展开更多
Drought indices are frequently used to measure the intensity,start and end of droughts.However,the performances of these indices depend on regions and the type of droughts.Therefore,it is necessary to evaluate whether...Drought indices are frequently used to measure the intensity,start and end of droughts.However,the performances of these indices depend on regions and the type of droughts.Therefore,it is necessary to evaluate whether these indices are applicable for a given region.This study evaluated the ability of the self-calibrating Palmer Drought Severity Index(sc PDSI),the Standardized Precipitation Evapotranspiration Index(SPEI),and the Standardized Moisture Anomaly Index(SZI) to describe the dry-wet conditions and drought events in the core zone of the “westerlies-dominated climatic regime”.The results showed that the 12-month SZI(SZI12) and SPEI(SPEI12) have good correlations with precipitation and PET respectively,while the sc PDSI can capture the changes in precipitation and soil moisture.In Xinjiang region of China,the SZI12 and sc PDSI showed that this region gradually became wetter during 1961–2014,which was consistent with increased precipitation,decreased PET,and improved vegetation.However,the SPEI12 showed significant drying due to the strong influence of the PET,suggesting that this index exaggerated the drought conditions in this region.Precipitation in Kazakhstan and the southern Central Asian regions has increased slightly over the past 50 years,but the PET has greatly increased,altogether,all three indices suggested a drying trend in Central Asia.The evaluation of the ability of these drought indices to identify typical drought events in Xinjiang region of China suggested that the sc PDSI can better detect the typical drought events compared with the SZI12.In conclusion,the sc PDSI is the most suitable index for characterizing the long-term trend of hydroclimate conditions and drought events in the core zone of the “westerlies-dominated climatic regime”.This study provides a theoretical basis for the rational utilization and improvement of the drought index,which is critical for monitoring,attributing,and predicting of drought events in arid areas.展开更多
In the multi-radar networking system,aiming at the problem of locating long-distance targets synergistically with difficulty and low accuracy,a dual-station joint positioning method based on the target measurement err...In the multi-radar networking system,aiming at the problem of locating long-distance targets synergistically with difficulty and low accuracy,a dual-station joint positioning method based on the target measurement error feature complementarity is proposed.For dual-station joint positioning,by constructing the target positioning error distribution model and using the complementarity of spatial measurement errors of the same long-distance target,the area with high probability of target existence can be obtained.Then,based on the target distance information,the midpoint of the intersection between the target positioning sphere and the positioning tangent plane can be solved to acquire the target's optimal positioning result.The simulation demonstrates that this method greatly improves the positioning accuracy of target in azimuth direction.Compared with the traditional the dynamic weighted fusion(DWF)algorithm and the filter-based dynamic weighted fusion(FBDWF)algorithm,it not only effectively eliminates the influence of systematic error in the azimuth direction,but also has low computational complexity.Furthermore,for the application scenarios of multi-radar collaborative positioning and multi-sensor data compression filtering in centralized information fusion,it is recommended that using radar with higher ranging accuracy and the lengths of baseline between radars are 20–100 km.展开更多
The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(R...The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.展开更多
This paper proposes a basic equation of thermal radiation interaction between surface objects on the basis of the principle of heat balance in the interface. The solution of this equation takes account of the contribu...This paper proposes a basic equation of thermal radiation interaction between surface objects on the basis of the principle of heat balance in the interface. The solution of this equation takes account of the contribution of sensible heat flux and latent heat flux more completely, compared with traditional solution for surface cooling and heating processes. By the aid of the experimental data conducted in the Xiaotangshan experimental site, Beijing, both the non-applicability of Kirchoff's law and the measurability of surface emissivity in a non-isothermal system have been highlighted. Two methods called ventilation and time-delay compensations have been proposed to reduce the error induced by change of surface temperatures of non-isothermal objects during the measurement of emissivity. Based on the solution of the basic equation, this paper has analyzed and pointed out the misunderstanding in comprehension and application of Kirchoff's law published in literature.展开更多
This review considers the fundamental dynamic processes involved in the laser heating of metal nanoparticles and their subsequent cooling.Of particular interest are the absorption of laser energy by nanoparticles,the ...This review considers the fundamental dynamic processes involved in the laser heating of metal nanoparticles and their subsequent cooling.Of particular interest are the absorption of laser energy by nanoparticles,the heating of a single nanoparticle or an ensemble thereof,and the dissipation of the energy of nanoparticles due to heat exchange with the environment.The goal is to consider the dependences and values of the temperatures of the nanoparticles and the environment,their time scales,and other parameters that describe these processes.Experimental results and analytical studies on the heating of single metal nanoparticles by laser pulses are discussed,including the laser thresholds for initiating subsequent photothermal processes,how temperature influences the optical properties,and the heating of gold nanoparticles by laser pulses.Experimental studies of the heating of an ensemble of nanoparticles and the results of an analytical study of the heating of an ensemble of nanoparticles and the environment by laser radiation are considered.Nanothermometry methods for nanoparticles under laser heating are considered,including changes in the refractive indices of metals and spectral thermometry of optical scattering of nanoparticles,Raman spectroscopy,the thermal distortion of the refractive index of an environment heated by a nanoparticle,and thermochemical phase transitions in lipid bilayers surrounding a heated nanoparticle.Understanding the sequence of events after radiation absorption and their time scales underlies many applications of nanoparticles.The applicationfields for the laser heating of nanoparticles are reviewed,including thermochemical reactions and selective nanophotothermolysis initiated in the environment by laser-heated nanoparticles,thermal radiation emission by nanoparticles and laser-induced incandescence,electron and ion emission of heated nanoparticles,and optothermal chemical catalysis.Applications of the laser heating of nanoparticles in laser nanomedicine are of particular interest.Significant emphasis is given to the proposed analytical approaches to modeling and calculating the heating processes under the action of a laser pulse on metal nanoparticles,taking into account the temperature dependences of the parameters.The proposed models can be used to estimate the parameters of lasers and nanoparticles in the various applicationfields for the laser heating of nanoparticles.展开更多
Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels wi...Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents.In this work,a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL^(-1) into multifunctional architectures under moderate centrifugation is illustrated.The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological,tribological,electrochemical,infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti_(3)C_(2)T_(x) nanosheets.By adopting a gel with optimized pH value,high lubrication,exceptional specific capacitances(~635 and~408 F g^(-1) at 5 and 100 mV s^(-1),respectively),long-term capacitance retention(~96.7%after 10,000 cycles)and high-precision screen-or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved,thus displaying extensive potential applications in the fields of semi-solid lubrication,control-lable devices,supercapacitors,information encryption and infrared camouflaging.展开更多
文摘The optimization of methods for the quantitative evaluation of risks in drilling engineering is an effective means to ensure safety in situations where high temperature and high pressure blocks are considered.In such a context,this study analyzes the complexity of the drilled wells in such blocks.It is shown that phenomena such as well kick,loss,circulation,and sticking,are related to the imbalance of wellbore pressure.A method for risk quantitative evaluation is proposed accordingly.The method is used to evaluate the risk for 9 drilled wells.By comparing the predictions of the method with actual historical data related to these wells,it is found that the coincidence rate is about 95%.
文摘Chinese domestic legislation on the judicial applicability of international treaties has been unsettled,especially under the Civil Code,which is silent on this issue.However,previous studies have depicted an image of a“pro-CISG”attitude in Chinese legal practice,which is distinguished from the tendency to circumvent the CISG in other jurisdictions such as the U.S.This contradictory phenomenon,namely the absence of guiding norms versus the embracement of the CISG in judicial practice,is rarely discussed,especially within the context of civil codification and recent external economic challenges.To verify this paradox,a manually collected dataset of 223 court decisions from 2013 to 2023 identifies some basic characteristics of the CISG judicial applicability in China,including the application rate,legal reasoning paths,citation frequencies of specific provisions,and some qualitative observations about the judicial behaviors in the international sales dispute resolution.The main finding is that Chinese courts have been applying the CISG at an obviously higher rate,compared with both their foreign counterparts and the general rate of applying foreign law in the international civil and commercial litigations in China.To explain this gap between“law in book”and“law in action,”the context of Chinese judicial practice should be considered.Despite the vagueness of domestic legislation,the judicial policy promotion,the innovative guiding cases system,the legal transplantation,and other factors may contribute to the“pro-CISG”attitude.As for the future promotion of CISG in the Chinese style of international commercial dispute resolution,these factors may coordinate with the legislative improvements.
基金Supported by Traditional Chinese Medicine and Ethnic Minority Medicine Technology Research Subject of Guizhou Administrative Bureau(QZYY-2018-095)。
文摘[Objectives]This study was conducted to establish a microbial limit test method for Qingyan Zhisou Powder.[Methods]Applicability tests were carried out according to Microbial Limit Tests of Non-sterile Products,General Rules 1105-1107 of Part IV of Chinese Pharmacopoeia,2020.[Results]Qingyan Zhisou Powder had a strong bacteriostatic effect on Pseudomonas aeruginosa.After increasing the dilution ratio(1:40),the bacteriostatic effect was obviously eliminated.When the total number of aerobic microbes was determined by the test liquid dilution method(1:40),the recovery values were in the range of 50%-200%;and when using the test liquid(1:10)to determine the total number of mold and yeasts,the recovery ranged from 50%to 200%.Escherichia coli,Salmonella and bile-tolerant Gram-negative bacteria were detected by both the routine method and dilution method in experimental groups.[Conclusions]The microbial limit test of Qingyan Zhisou Powder adopted the test liquid dilution method,and the routine method could be used for the test of Escherichia coli,Salmonella and bile-tolerant Gram-negative bacteria.The applicability test of the method is feasible,with scientific and accurate results,and the method can effectively control the quality of the preparation and is recommended for popularization.
基金Sponsored by 2022 Beijing Undergraduate Innovation and Entrepreneurship Training PlanConstruction of Demonstration Off-campus Practice Base for Integration of Industry and Education+1 种基金Beijing Municipal Education Commission Social Science Project(KM202010009002)“Young Yu You Talents Training Plan”of North China University of Technology。
文摘In order to understand the travel characteristics and behavior patterns of women in Wangjing area and explore whether the existing situation can meet women's needs for the use of street space,the area around Wangjing South Station of Metro Line 14 was taken as an example for analysis and research.Wangjing area was classified to the following six use attributes:company enterprise,transportation hub,education and culture,residential area,municipal facilities,leisure and entertainment.The proportion of each use attribute was evaluated according to four levels:A 25%and above(including 25%),B 15%-25%,C 15%-5%,D 5%and below(including 5%).Finally,whether the plot had composite functions was judged,and the spatio-temporal laws and behavior patterns of surrounding women were analyzed from the perspectives of time and space.
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.
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 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.
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.
文摘The applicability of Tropical Rainfall Measuring Mission (TRMM3B42V7) precipitation data in the region was evaluated using the measured daily precipitation data in 16 hydrological stations in Shaanxi Province from 1998 to 2014. The evaluation process with several statistical error metrics was applied to daily, monthly, and annual timescale. The results show that the satellite and gauge stations show good consistency for monthly and annual timescale, but rather worse accuracy of daily timescale. All timescales produced the overestimated result of average precipitation measurement. The spatially statistical distribution shows a slight correlation between the observation and satellite estimation, especially at the higher elevation area such as Taibai. The TRMM precipitation value is closer to the gauge station precipitation value at a place with lower elevation, whether the timescale is daily, monthly or annual. At the same time, the smaller timescale leads to closer relations between elevation and metrics. The research results are important value of the research study of meteorological process in the Qinba mountain area.
文摘Due to the exhaustion of IPv4 address resources, the transition from IPv4 to IPv6 is inevitable and fairly urgent. Numerous transition mechanisms have been proposed to solve challenging issues of IPv6 transition. An inter-connection between IPv4 and IPv6 networks or hosts requirement has been happening throughout the IPv6 transition process. And one-time translation scheme is indispensable to achieve the inter-connection. In addition, double translation can be used in the IPv4-IPv6-IPv4 scenario. As a long-term strategy, translation scheme is important and inevitable. However, because of the diverse characteristics and transition requirements of practical networks and the lack of applicability analysis, the selection and deployment of transition mechanisms are facing with grand challenges. Targeting at those challenges, this paper investigates the basic issues and key elements of IPv6 translation transition mechanisms, and presents its first applicability index system. In particular, we analyze the applicability of existing proposed translation techniques based on the presented index system, which has significant guidance in the practical deployment of IPv6 transition techniques.
文摘Lakes are an important component of the earth climate system. They play an important role in the study of basin weather forecasting, air quality forecasting, and regional climate research. The accuracy of driving variables is the basic premise to ensure the rationality of lake mode simulation. Based on the in-situ observations at Bifenggang site of the Lake Taihu Eddy flux Network from 2012 to 2017, this paper investigated temporal variations in temperature, relative humidity, wind speed, radiation components at different time scales (hourly, seasonal and interannual). ERA5 reanalysis data were compared with in-situ observation to quantify the error and evaluate the performance of reanalysis data. The results show that: 1) On the hourly scale, the ERA5 reanalysis data described air temperature, and downward long-wave radiation more accurately. 2) On the seasonal variation scale, the ERA5 reanalysis data described air temperature, and downward long-wave radiation more accurately. However, the descriptions of wind speed, relative humidity and downward short-wave have large deviations. 3) On the interannual scale, the ERA5 reanalysis data show a good performance for temperature, followed by downward longwave radiation, downward shortwave radiation and relative humidity.
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.
文摘Brown and Levinson's face theory is a theory of interpersonal relationship. It has successfully explained the influence of "face"in people's daily communications. The theory is built on the basis of western culture and ignores the cultural difference of "face"in China. It is not free from limitations the absoluteness of which exerts a checking effort on its universal applicability. This paper probes from the perspective of the influence of context and culture that the application of Face-Saving theory in actual communications in China, especially from those restrictions on the use of negative face in China.
基金supported by the National Key R&D Program of China (Grant No.2018YFA0606404)the National Natural Science Foundation of China (Grant No.41877446)。
文摘Drought indices are frequently used to measure the intensity,start and end of droughts.However,the performances of these indices depend on regions and the type of droughts.Therefore,it is necessary to evaluate whether these indices are applicable for a given region.This study evaluated the ability of the self-calibrating Palmer Drought Severity Index(sc PDSI),the Standardized Precipitation Evapotranspiration Index(SPEI),and the Standardized Moisture Anomaly Index(SZI) to describe the dry-wet conditions and drought events in the core zone of the “westerlies-dominated climatic regime”.The results showed that the 12-month SZI(SZI12) and SPEI(SPEI12) have good correlations with precipitation and PET respectively,while the sc PDSI can capture the changes in precipitation and soil moisture.In Xinjiang region of China,the SZI12 and sc PDSI showed that this region gradually became wetter during 1961–2014,which was consistent with increased precipitation,decreased PET,and improved vegetation.However,the SPEI12 showed significant drying due to the strong influence of the PET,suggesting that this index exaggerated the drought conditions in this region.Precipitation in Kazakhstan and the southern Central Asian regions has increased slightly over the past 50 years,but the PET has greatly increased,altogether,all three indices suggested a drying trend in Central Asia.The evaluation of the ability of these drought indices to identify typical drought events in Xinjiang region of China suggested that the sc PDSI can better detect the typical drought events compared with the SZI12.In conclusion,the sc PDSI is the most suitable index for characterizing the long-term trend of hydroclimate conditions and drought events in the core zone of the “westerlies-dominated climatic regime”.This study provides a theoretical basis for the rational utilization and improvement of the drought index,which is critical for monitoring,attributing,and predicting of drought events in arid areas.
文摘In the multi-radar networking system,aiming at the problem of locating long-distance targets synergistically with difficulty and low accuracy,a dual-station joint positioning method based on the target measurement error feature complementarity is proposed.For dual-station joint positioning,by constructing the target positioning error distribution model and using the complementarity of spatial measurement errors of the same long-distance target,the area with high probability of target existence can be obtained.Then,based on the target distance information,the midpoint of the intersection between the target positioning sphere and the positioning tangent plane can be solved to acquire the target's optimal positioning result.The simulation demonstrates that this method greatly improves the positioning accuracy of target in azimuth direction.Compared with the traditional the dynamic weighted fusion(DWF)algorithm and the filter-based dynamic weighted fusion(FBDWF)algorithm,it not only effectively eliminates the influence of systematic error in the azimuth direction,but also has low computational complexity.Furthermore,for the application scenarios of multi-radar collaborative positioning and multi-sensor data compression filtering in centralized information fusion,it is recommended that using radar with higher ranging accuracy and the lengths of baseline between radars are 20–100 km.
基金supported by the National Key Research and Development Program of China(No.2023YFC2907600)the National Natural Science Foundation of China(Nos.42077267,42277174 and 52074164)+2 种基金the Natural Science Foundation of Shandong Province,China(No.ZR2020JQ23)the Opening Project of State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology(No.KFJJ21-02Z)the Fundamental Research Funds for the Central Universities,China(No.2022JCCXSB03).
文摘The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.
基金This work was supported by the National Basic Research Project(Grant No.2000077900)the Key Project of the National Natural Science Foundation of China(Grant Nos.49890330 and 40371089)+1 种基金the Knowledge Innovation Project of Ins titute of Geographical SciencesNatural Resources Research,Chinese Academy of Sciences(Grant Nos.CXIOG-C00-05-02 and CXIOG-E01-01-04).
文摘This paper proposes a basic equation of thermal radiation interaction between surface objects on the basis of the principle of heat balance in the interface. The solution of this equation takes account of the contribution of sensible heat flux and latent heat flux more completely, compared with traditional solution for surface cooling and heating processes. By the aid of the experimental data conducted in the Xiaotangshan experimental site, Beijing, both the non-applicability of Kirchoff's law and the measurability of surface emissivity in a non-isothermal system have been highlighted. Two methods called ventilation and time-delay compensations have been proposed to reduce the error induced by change of surface temperatures of non-isothermal objects during the measurement of emissivity. Based on the solution of the basic equation, this paper has analyzed and pointed out the misunderstanding in comprehension and application of Kirchoff's law published in literature.
文摘This review considers the fundamental dynamic processes involved in the laser heating of metal nanoparticles and their subsequent cooling.Of particular interest are the absorption of laser energy by nanoparticles,the heating of a single nanoparticle or an ensemble thereof,and the dissipation of the energy of nanoparticles due to heat exchange with the environment.The goal is to consider the dependences and values of the temperatures of the nanoparticles and the environment,their time scales,and other parameters that describe these processes.Experimental results and analytical studies on the heating of single metal nanoparticles by laser pulses are discussed,including the laser thresholds for initiating subsequent photothermal processes,how temperature influences the optical properties,and the heating of gold nanoparticles by laser pulses.Experimental studies of the heating of an ensemble of nanoparticles and the results of an analytical study of the heating of an ensemble of nanoparticles and the environment by laser radiation are considered.Nanothermometry methods for nanoparticles under laser heating are considered,including changes in the refractive indices of metals and spectral thermometry of optical scattering of nanoparticles,Raman spectroscopy,the thermal distortion of the refractive index of an environment heated by a nanoparticle,and thermochemical phase transitions in lipid bilayers surrounding a heated nanoparticle.Understanding the sequence of events after radiation absorption and their time scales underlies many applications of nanoparticles.The applicationfields for the laser heating of nanoparticles are reviewed,including thermochemical reactions and selective nanophotothermolysis initiated in the environment by laser-heated nanoparticles,thermal radiation emission by nanoparticles and laser-induced incandescence,electron and ion emission of heated nanoparticles,and optothermal chemical catalysis.Applications of the laser heating of nanoparticles in laser nanomedicine are of particular interest.Significant emphasis is given to the proposed analytical approaches to modeling and calculating the heating processes under the action of a laser pulse on metal nanoparticles,taking into account the temperature dependences of the parameters.The proposed models can be used to estimate the parameters of lasers and nanoparticles in the various applicationfields for the laser heating of nanoparticles.
基金This work is financially supported by the Hundred Talents Program of Chinese Academy of Sciences(E30247YB)the Special Talents Program of Lanzhou Institute of Chemical Physics(E0SX0282)+1 种基金the National Natural Science Foundation of Shandong Province(ZR2022QB190)the Innovative Research Funds of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(E1R06SXM07,E1R06SXM09 and E2R06SXM14).
文摘Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents.In this work,a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL^(-1) into multifunctional architectures under moderate centrifugation is illustrated.The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological,tribological,electrochemical,infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti_(3)C_(2)T_(x) nanosheets.By adopting a gel with optimized pH value,high lubrication,exceptional specific capacitances(~635 and~408 F g^(-1) at 5 and 100 mV s^(-1),respectively),long-term capacitance retention(~96.7%after 10,000 cycles)and high-precision screen-or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved,thus displaying extensive potential applications in the fields of semi-solid lubrication,control-lable devices,supercapacitors,information encryption and infrared camouflaging.
