By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily...By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily change characteristics of pollute boundary layer in winter in the area were discussed. The results showed that the pollute boundary layer in the river outlet area of Grand Liao River was affected by the sea and land. In the certain weather condition,maybe the sea-land breeze appeared in the low altitude which was below 200 m in the coastal zone. The stability change in the different height in the coastal zone was more stable than in the land zone,and the wind field change in the area was mainly in 300 m low altitude. At night,the temperature inversion often appears in the area,and the thickness of temperature inversion layer is stably during 200-300 m. The thermal internal boundary layer penetrated deeply into the land about 10 km,and the height could reach 800 m. The atmospheric diffusion ability in the coastal area was weaker and stronger in the land area.展开更多
The 37th Language Testing Research Colloquium(LTRC 2015①)was held at Eaton Chelsea Hotel in Toronto Canada during March 16-20,2015.The first two days of March 16-17 were preconference workshop days with March 18-20 a...The 37th Language Testing Research Colloquium(LTRC 2015①)was held at Eaton Chelsea Hotel in Toronto Canada during March 16-20,2015.The first two days of March 16-17 were preconference workshop days with March 18-20 as the three main conference days.More than 300 participants from 27 countries and regions joined the conference.The top numbers of the展开更多
750 kV substation of Riyue Mountain, Qinghai is a substation that annual average thunderstorm days are the maximum at the same volt- age level and altitude in the wodd. We detailedly described testing methods and step...750 kV substation of Riyue Mountain, Qinghai is a substation that annual average thunderstorm days are the maximum at the same volt- age level and altitude in the wodd. We detailedly described testing methods and steps of 6 characteristic parameters for grounding device of 750 kV substation by using 8000S comprehensive test system, and scientifically judged overall performance of the grounding device. Moreover, we espe- cially emphasized key and difficult points in testing process, providing reference for the majority of grounding test workers.展开更多
A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection co...A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection control method is given out and the control accuracy can be 0.1° crank degree. The bench can test both mechanical unit pump and electronic unit pump. A test model-PLD12 electronic unit pump is tested. Full pump delivery map and some influence factors test is done. Experimental results show that the injection quantity is linear with the delivery angle. The quantity change rate is 15% when fuel temperature increases 30 ℃. The delivery quantity per cycle increases 30 mg at 28 V drive voltage. The average delivery difference for two same type pumps is 5 %. Test results show that the bench can be used for unit pump verification.展开更多
The sonic fatigue life of the aluminium rectangular panel was calculated using the concise method[1], and the sonic fatigue test was conducted on progressive wave tube (PWT) test facility. A comparison was made betwee...The sonic fatigue life of the aluminium rectangular panel was calculated using the concise method[1], and the sonic fatigue test was conducted on progressive wave tube (PWT) test facility. A comparison was made between the results of calculation and test, and it shows reasonable agreement between these two results.展开更多
As many chemicals with genotoxic potential are emitted to surface water, genotoxicity tests are gaining importance which led to the development of several techniques to detect directly DNA damage. The relevance of det...As many chemicals with genotoxic potential are emitted to surface water, genotoxicity tests are gaining importance which led to the development of several techniques to detect directly DNA damage. The relevance of detecting the genotoxic risks associated with water pollution was firstly perceived in the late 1970s. Since that time several tests have been developed for evaluating DNA alterations in aquatic animals. These tests rely on the premise that any changes to DNA may have long-lasting and profound consequences. Sister chromatid test, chromosome aberrations, comet assay, and micronucleus test are currently the most widely employed methods to detect DNA lesions in ecotoxicology. Chromosomal aberration and sister chromatid exchanges are time consuming, resource intensive and require proliferating cell population. Hence, Comet assay and Micronucleus test as cost effective and more sensitive test systems have now been introduced for assessing the genotoxicity of chemicals. This review presents a synthesis of the state of the art in the methodologies of comet assay and micronucleus test and their contributions in aquatic environmental research. The text explores the latest knowledge and thinking on these very important approaches for the assessment of environmental health, management, and conservation. The primary concern of the present review is the measurement of genotoxic potential in aquatic organisms under field and laboratory conditions, where effects of chemicals at different levels of biological organization can be examined.展开更多
提出一种面向正向研发的机载设备故障诊断设计方法。针对传统人工测试方法在效率、覆盖率和动态响应验证中的不足,基于系统工程范式,构建覆盖“需求-模型-诊断-验证”的数字化设计链路。基于Simulink可视化建模和MATLAB测试管理框架,完...提出一种面向正向研发的机载设备故障诊断设计方法。针对传统人工测试方法在效率、覆盖率和动态响应验证中的不足,基于系统工程范式,构建覆盖“需求-模型-诊断-验证”的数字化设计链路。基于Simulink可视化建模和MATLAB测试管理框架,完成高保真系统建模、多模态测试用例生成、代码转换和软件在环(Software-in-the-Loop,SIL)验证,并创新性地将故障诊断设计前移至预先研究阶段。将航空发动机起动空气阀(Starting Air Valve,SAV)控制电路作为典型案例,通过动态故障注入和诊断方案优化,验证了该方法在缩短测试周期、降低研发成本和增强系统可靠性方面具有显著优势。所研究的故障诊断设计结果可反馈至航空发动机控制系统等机载复杂装备的正向研发流程,对推动装备研制模式的数字化转型具有重要工程价值。展开更多
Despite decades of research, at present there is no curative therapy for Alzheimer＇s disease. Changes in the way new drugs are tested appear to be necessary. Three changes are presented here and will be discussed. Th...Despite decades of research, at present there is no curative therapy for Alzheimer＇s disease. Changes in the way new drugs are tested appear to be necessary. Three changes are presented here and will be discussed. The first change is that Alzheimer＇s disease must be considered a disease of four major pathological processes, not one. The four processes are： 1） vascular hy- poperfusion of the brain with associated mitochondrial dysfunction, 2） destructive protein inclusions, 3） uncontrolled oxidative stress, and 4） proinflammatory immune processes second- ary to microglial and astrocytic dysfunction in the brain. The second change recommended is to alter the standard cognitive measurement tools used to quantify mental decline in test patients. Specifically the Dementia Severity Rating Scale （DSRS） should supersede Mini-Mental State Examination （MMSE） and other popular tests, and a measurement scale developed in research should be used to produce a linear and non-irregular baseline. Finally, accepting the concept that four etiologies cause Alzheimer＇s disease leads to the last necessary change, that new thera- pies must be employed directed against all four causes, likely as a combination. There are drugs ready to be employed in such a combinations which are available and used clinically for other purposes so can be used ＂offlabel＂ and one such combination is suggested.展开更多
This paper deals with the influence of water content on the mechanical properties of gypsum breccia with different initial water contents. The experimental research was taken on the GDS (geotechnical digital systems) ...This paper deals with the influence of water content on the mechanical properties of gypsum breccia with different initial water contents. The experimental research was taken on the GDS (geotechnical digital systems) tri-axial experiment system by strain rate control. The mechanical properties,including stress-strain curves,peak deviator stress,relative residual strength,elastic modulus,Poisson's ratio,angle of internal friction and cohesion of gypsum breccia,were studied by experiment. The results showed that the water content has obvious infiuence on the mechanical properties of gypsum breccia. With increasing of water content,the angle of internal friction and cohesion of gypsum breccia decrease linearly. Meanwhile,the stress-strain curves go through from the declining,hump curve to the strain hardening curve. At the same confining pressure,the peak deviator stress and elastic modulus decrease exponentially,while Poisson's ratio increases linearly with the increasing of the water content. At the same water content,with increasing of the confining pressure,the peak deviator stress,elastic modulus and the peak deviator stress increase trend but Poisson's ratio decreases at a lower water content. While at a high water contents,the Poisson's ratio doesn't change much. It shows that water content plays an important role in the process of changing from the brittleness to plastic for the mechanical properties of gypsum breccia.展开更多
This study explored and reviewed the logistic regression (LR) model, a multivariable method for modeling the relationship between multiple independent variables and a categorical dependent variable, with emphasis on m...This study explored and reviewed the logistic regression (LR) model, a multivariable method for modeling the relationship between multiple independent variables and a categorical dependent variable, with emphasis on medical research. Thirty seven research articles published between 2000 and 2018 which employed logistic regression as the main statistical tool as well as six text books on logistic regression were reviewed. Logistic regression concepts such as odds, odds ratio, logit transformation, logistic curve, assumption, selecting dependent and independent variables, model fitting, reporting and interpreting were presented. Upon perusing the literature, considerable deficiencies were found in both the use and reporting of LR. For many studies, the ratio of the number of outcome events to predictor variables (events per variable) was sufficiently small to call into question the accuracy of the regression model. Also, most studies did not report on validation analysis, regression diagnostics or goodness-of-fit measures;measures which authenticate the robustness of the LR model. Here, we demonstrate a good example of the application of the LR model using data obtained on a cohort of pregnant women and the factors that influence their decision to opt for caesarean delivery or vaginal birth. It is recommended that researchers should be more rigorous and pay greater attention to guidelines concerning the use and reporting of LR models.展开更多
Mother-to-child-transmission of human immunodeficiency virus(HIV) is a primary cause of pediatric infections with HIV. Many of these infections involve women who were not tested early enough in pregnancy, or who didno...Mother-to-child-transmission of human immunodeficiency virus(HIV) is a primary cause of pediatric infections with HIV. Many of these infections involve women who were not tested early enough in pregnancy, or who didnot receive prevention services. HIV testing of pregnant women is considered to be one of the key strategies for preventing mother-to-child-transmission of HIV, but HIV testing rates among pregnant women in various countries remain suboptimal. Understanding the factors relating to women's willingness to be tested for HIV during pregnancy is critical for developing strategies to increase HIV testing rates among pregnant women. Extensive research points to various factors relating to women's willingness to be tested for HIV during pregnancy, and various recommendations aimed at improving testing rates among pregnant women have been suggested based on the research. In light of the goals set by the United Nations to reduce the rate of infants infected with HIV, it is necessary to summarize what is currently known regarding factors related to women's willingness to be tested for HIV during pregnancy. The purpose of this review is therefore to examine factors related to women's willingness to be tested for HIV during pregnancy, and to summarize recommendations for practice and further research.展开更多
Objective： This study compared the performance of the immunochromatographic strip （ICS） to the Venereal Disease Research Laboratory （VDRL） test and Treponema pallidum haemagglutination assay （TPHA） at a primary...Objective： This study compared the performance of the immunochromatographic strip （ICS） to the Venereal Disease Research Laboratory （VDRL） test and Treponema pallidum haemagglutination assay （TPHA） at a primary health care setting. Methods： The study group was comprised of 150 females randomly drawn from a population of pregnant women attending their first antenatal visit or follow-up visits at West Maternity Hospital in Eldoret Kenya, but without a previous syphilis test during that pregnancy. On-site VDRL, ICS and TPHA tests were performed and immediate treatment provided where appropriate. The performance of the three tests was compared, Results： The sero-prevalence of syphilis as determined by the VDRL test was 3%. There was no significant difference between the ICS and the VDRL test （P 〉 0.05）. The sensitivity and specificity of the ICS test were 80% and 98.6% respectively, while the negative predictive value （NPV） and positive predictive value （PPV） were both 100%. On the other hand, the sensitivity and specificity of the VDRL test were 66.7% and 99.3%, while the NPV and PPV were 80% and 98.6% respectively. The Treponema pallidum haemagglutination assay was used as a reference test and had sensitivity, specificity, NPV and PPV of 100%. Conclusion： The diagnostic accuracy of the ICS compared favorably with theVDRL gold standard. The use of the ICS in Kenya can improve the diagnosis of syphilis in health facilities both with and without laboratories and allow community health care workers to make a rapid diagnosis of the disease, and consequently make immediate therapeutic decisions.展开更多
基金Supported by The Special Project of Public Welfare Industry(Meteorology)of Science and Technology Ministry(GYHY200806020)The National Natural Science Fund(40975084)The Science Research Fund of Liaoning Meteorological Bureau(2008008)
文摘By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily change characteristics of pollute boundary layer in winter in the area were discussed. The results showed that the pollute boundary layer in the river outlet area of Grand Liao River was affected by the sea and land. In the certain weather condition,maybe the sea-land breeze appeared in the low altitude which was below 200 m in the coastal zone. The stability change in the different height in the coastal zone was more stable than in the land zone,and the wind field change in the area was mainly in 300 m low altitude. At night,the temperature inversion often appears in the area,and the thickness of temperature inversion layer is stably during 200-300 m. The thermal internal boundary layer penetrated deeply into the land about 10 km,and the height could reach 800 m. The atmospheric diffusion ability in the coastal area was weaker and stronger in the land area.
文摘The 37th Language Testing Research Colloquium(LTRC 2015①)was held at Eaton Chelsea Hotel in Toronto Canada during March 16-20,2015.The first two days of March 16-17 were preconference workshop days with March 18-20 as the three main conference days.More than 300 participants from 27 countries and regions joined the conference.The top numbers of the
文摘750 kV substation of Riyue Mountain, Qinghai is a substation that annual average thunderstorm days are the maximum at the same volt- age level and altitude in the wodd. We detailedly described testing methods and steps of 6 characteristic parameters for grounding device of 750 kV substation by using 8000S comprehensive test system, and scientifically judged overall performance of the grounding device. Moreover, we espe- cially emphasized key and difficult points in testing process, providing reference for the majority of grounding test workers.
基金the Ministerial Level Advanced Research Foundation (404050301 .4)
文摘A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection control method is given out and the control accuracy can be 0.1° crank degree. The bench can test both mechanical unit pump and electronic unit pump. A test model-PLD12 electronic unit pump is tested. Full pump delivery map and some influence factors test is done. Experimental results show that the injection quantity is linear with the delivery angle. The quantity change rate is 15% when fuel temperature increases 30 ℃. The delivery quantity per cycle increases 30 mg at 28 V drive voltage. The average delivery difference for two same type pumps is 5 %. Test results show that the bench can be used for unit pump verification.
文摘The sonic fatigue life of the aluminium rectangular panel was calculated using the concise method[1], and the sonic fatigue test was conducted on progressive wave tube (PWT) test facility. A comparison was made between the results of calculation and test, and it shows reasonable agreement between these two results.
文摘As many chemicals with genotoxic potential are emitted to surface water, genotoxicity tests are gaining importance which led to the development of several techniques to detect directly DNA damage. The relevance of detecting the genotoxic risks associated with water pollution was firstly perceived in the late 1970s. Since that time several tests have been developed for evaluating DNA alterations in aquatic animals. These tests rely on the premise that any changes to DNA may have long-lasting and profound consequences. Sister chromatid test, chromosome aberrations, comet assay, and micronucleus test are currently the most widely employed methods to detect DNA lesions in ecotoxicology. Chromosomal aberration and sister chromatid exchanges are time consuming, resource intensive and require proliferating cell population. Hence, Comet assay and Micronucleus test as cost effective and more sensitive test systems have now been introduced for assessing the genotoxicity of chemicals. This review presents a synthesis of the state of the art in the methodologies of comet assay and micronucleus test and their contributions in aquatic environmental research. The text explores the latest knowledge and thinking on these very important approaches for the assessment of environmental health, management, and conservation. The primary concern of the present review is the measurement of genotoxic potential in aquatic organisms under field and laboratory conditions, where effects of chemicals at different levels of biological organization can be examined.
文摘提出一种面向正向研发的机载设备故障诊断设计方法。针对传统人工测试方法在效率、覆盖率和动态响应验证中的不足,基于系统工程范式,构建覆盖“需求-模型-诊断-验证”的数字化设计链路。基于Simulink可视化建模和MATLAB测试管理框架,完成高保真系统建模、多模态测试用例生成、代码转换和软件在环(Software-in-the-Loop,SIL)验证,并创新性地将故障诊断设计前移至预先研究阶段。将航空发动机起动空气阀(Starting Air Valve,SAV)控制电路作为典型案例,通过动态故障注入和诊断方案优化,验证了该方法在缩短测试周期、降低研发成本和增强系统可靠性方面具有显著优势。所研究的故障诊断设计结果可反馈至航空发动机控制系统等机载复杂装备的正向研发流程,对推动装备研制模式的数字化转型具有重要工程价值。
文摘Despite decades of research, at present there is no curative therapy for Alzheimer＇s disease. Changes in the way new drugs are tested appear to be necessary. Three changes are presented here and will be discussed. The first change is that Alzheimer＇s disease must be considered a disease of four major pathological processes, not one. The four processes are： 1） vascular hy- poperfusion of the brain with associated mitochondrial dysfunction, 2） destructive protein inclusions, 3） uncontrolled oxidative stress, and 4） proinflammatory immune processes second- ary to microglial and astrocytic dysfunction in the brain. The second change recommended is to alter the standard cognitive measurement tools used to quantify mental decline in test patients. Specifically the Dementia Severity Rating Scale （DSRS） should supersede Mini-Mental State Examination （MMSE） and other popular tests, and a measurement scale developed in research should be used to produce a linear and non-irregular baseline. Finally, accepting the concept that four etiologies cause Alzheimer＇s disease leads to the last necessary change, that new thera- pies must be employed directed against all four causes, likely as a combination. There are drugs ready to be employed in such a combinations which are available and used clinically for other purposes so can be used ＂offlabel＂ and one such combination is suggested.
文摘This paper deals with the influence of water content on the mechanical properties of gypsum breccia with different initial water contents. The experimental research was taken on the GDS (geotechnical digital systems) tri-axial experiment system by strain rate control. The mechanical properties,including stress-strain curves,peak deviator stress,relative residual strength,elastic modulus,Poisson's ratio,angle of internal friction and cohesion of gypsum breccia,were studied by experiment. The results showed that the water content has obvious infiuence on the mechanical properties of gypsum breccia. With increasing of water content,the angle of internal friction and cohesion of gypsum breccia decrease linearly. Meanwhile,the stress-strain curves go through from the declining,hump curve to the strain hardening curve. At the same confining pressure,the peak deviator stress and elastic modulus decrease exponentially,while Poisson's ratio increases linearly with the increasing of the water content. At the same water content,with increasing of the confining pressure,the peak deviator stress,elastic modulus and the peak deviator stress increase trend but Poisson's ratio decreases at a lower water content. While at a high water contents,the Poisson's ratio doesn't change much. It shows that water content plays an important role in the process of changing from the brittleness to plastic for the mechanical properties of gypsum breccia.
文摘This study explored and reviewed the logistic regression (LR) model, a multivariable method for modeling the relationship between multiple independent variables and a categorical dependent variable, with emphasis on medical research. Thirty seven research articles published between 2000 and 2018 which employed logistic regression as the main statistical tool as well as six text books on logistic regression were reviewed. Logistic regression concepts such as odds, odds ratio, logit transformation, logistic curve, assumption, selecting dependent and independent variables, model fitting, reporting and interpreting were presented. Upon perusing the literature, considerable deficiencies were found in both the use and reporting of LR. For many studies, the ratio of the number of outcome events to predictor variables (events per variable) was sufficiently small to call into question the accuracy of the regression model. Also, most studies did not report on validation analysis, regression diagnostics or goodness-of-fit measures;measures which authenticate the robustness of the LR model. Here, we demonstrate a good example of the application of the LR model using data obtained on a cohort of pregnant women and the factors that influence their decision to opt for caesarean delivery or vaginal birth. It is recommended that researchers should be more rigorous and pay greater attention to guidelines concerning the use and reporting of LR models.
文摘Mother-to-child-transmission of human immunodeficiency virus(HIV) is a primary cause of pediatric infections with HIV. Many of these infections involve women who were not tested early enough in pregnancy, or who didnot receive prevention services. HIV testing of pregnant women is considered to be one of the key strategies for preventing mother-to-child-transmission of HIV, but HIV testing rates among pregnant women in various countries remain suboptimal. Understanding the factors relating to women's willingness to be tested for HIV during pregnancy is critical for developing strategies to increase HIV testing rates among pregnant women. Extensive research points to various factors relating to women's willingness to be tested for HIV during pregnancy, and various recommendations aimed at improving testing rates among pregnant women have been suggested based on the research. In light of the goals set by the United Nations to reduce the rate of infants infected with HIV, it is necessary to summarize what is currently known regarding factors related to women's willingness to be tested for HIV during pregnancy. The purpose of this review is therefore to examine factors related to women's willingness to be tested for HIV during pregnancy, and to summarize recommendations for practice and further research.
文摘Objective： This study compared the performance of the immunochromatographic strip （ICS） to the Venereal Disease Research Laboratory （VDRL） test and Treponema pallidum haemagglutination assay （TPHA） at a primary health care setting. Methods： The study group was comprised of 150 females randomly drawn from a population of pregnant women attending their first antenatal visit or follow-up visits at West Maternity Hospital in Eldoret Kenya, but without a previous syphilis test during that pregnancy. On-site VDRL, ICS and TPHA tests were performed and immediate treatment provided where appropriate. The performance of the three tests was compared, Results： The sero-prevalence of syphilis as determined by the VDRL test was 3%. There was no significant difference between the ICS and the VDRL test （P 〉 0.05）. The sensitivity and specificity of the ICS test were 80% and 98.6% respectively, while the negative predictive value （NPV） and positive predictive value （PPV） were both 100%. On the other hand, the sensitivity and specificity of the VDRL test were 66.7% and 99.3%, while the NPV and PPV were 80% and 98.6% respectively. The Treponema pallidum haemagglutination assay was used as a reference test and had sensitivity, specificity, NPV and PPV of 100%. Conclusion： The diagnostic accuracy of the ICS compared favorably with theVDRL gold standard. The use of the ICS in Kenya can improve the diagnosis of syphilis in health facilities both with and without laboratories and allow community health care workers to make a rapid diagnosis of the disease, and consequently make immediate therapeutic decisions.
