Inductively-coupled plasma mass spectrometry (ICP-MS) has made much progress since its birth in the late 1990s. This paper will give a rather systematic overview on the use of this technique in new devices and technol...Inductively-coupled plasma mass spectrometry (ICP-MS) has made much progress since its birth in the late 1990s. This paper will give a rather systematic overview on the use of this technique in new devices and technologies related to plasma source, sample-introducing device and detecting spectrometer etc. In this overview, an emphasis will be put on the evaluation of the ICP- MS technique in combination with a series of physical, chemical and biological techniques, such as laser ablation (LA), capillary electrophoresis (CE) and high performance liquid chromatograph (HPLC), along with their representative high accuracy and high sensitivity. Finally, comprehensive and fruitful applications of the ICP-MS and its combinative techniques in the detection of trace metallic elements and isotopes in complex biological and environmental samples will be revealed.展开更多
Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applic...Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applications. The Terahertz region has been the focus of research worldwide since early 1990s. Due to their unique characteristics, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, and biomedical imaging.展开更多
Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applic...Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applications. The Terahertz region has been the focus of research worldwide since early 1990s. Due to their unique characteristics, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, and biomedical imaging.展开更多
Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applic...Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applications. The Terahertz region has been the focus of research worldwide since early 1990s. Due to their unique characteristics, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, and biomedical imaging.展开更多
Terahertz wave, sitting in the gap between middle infrared and millimeter wave, has been known as the last vacant area in spectrum that has not been quite understood and brought into applications. It has been the focu...Terahertz wave, sitting in the gap between middle infrared and millimeter wave, has been known as the last vacant area in spectrum that has not been quite understood and brought into applications. It has been the focus of research worldwide since early 1990s. Due to the unique characteristics of Terahertz wave, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, biomedical imaging, etc.展开更多
In this paper expressions for the solution and general properties (wave energy, radiation stress, etc.) of the first-order cnoidal wave theory are given as a power series of the complementary modulus of the theta func...In this paper expressions for the solution and general properties (wave energy, radiation stress, etc.) of the first-order cnoidal wave theory are given as a power series of the complementary modulus of the theta function. These expressions are convenient for numerical calculation because they converge very rapidly over the applicable range of Ursell number (Us> 10) for the theory. As examples of practical application, the relative height of wave crest, maximum bottom velocity, radiation stress, wave set-down and set-up are calculated. Comparisons between calculated values and experimental data are made.展开更多
Online education has attracted a large number of students in recent years, because it breaks through the limitations of time and space and makes high-quality education at your fingertips. The method of predicting stud...Online education has attracted a large number of students in recent years, because it breaks through the limitations of time and space and makes high-quality education at your fingertips. The method of predicting student performance is to analyze and predict the student’s final performance by collecting demographic data such as the student’s gender, age, and highest education level, and clickstream data generated when students interact with VLE in different types of specific courses, which are widely used in online education platforms. This article proposes a model to predict student performance via Attention-based Multi-layer LSTM (AML), which combines student demographic data and clickstream data for comprehensive analysis. We hope that we can obtain a higher prediction accuracy as soon as possible to provide timely intervention. The results show that the proposed model can improve the accuracy of 0.52% - 0.85% and the F1 score of 0.89% - 2.30% on the four-class classification task as well as the accuracy of 0.15% - 0.97% and the F1 score of 0.21% - 2.77% on the binary classification task from week 5 to week 25.展开更多
This article firstly explains the concepts of artificial intelligence and algorithm separately,then determines the research status of artificial intelligence and machine learning in the background of the increasing po...This article firstly explains the concepts of artificial intelligence and algorithm separately,then determines the research status of artificial intelligence and machine learning in the background of the increasing popularity of artificial intelligence,and finally briefly describes the machine learning algorithm in the field of artificial intelligence,as well as puts forward appropriate development prospects,in order to provide theoretical reference for industry insider.展开更多
In this paper, the AC-excited helium discharges generated between the powered needle electrode enclosed in a conical quartz tube and the grounded de-ionized water electrode are investigated. The current and voltage wa...In this paper, the AC-excited helium discharges generated between the powered needle electrode enclosed in a conical quartz tube and the grounded de-ionized water electrode are investigated. The current and voltage waveforms exhibit a transition from the glow-like to streamer-like mode discharges, which forms a stable cone-shaped structure at the gas-liquid interface. In this region, the air and water vapor diffusion initiate various physical-chemical processes leading to substantial changes of the primary species emission intensities （e.g., OH, N2, NO, and O） and the rotational temperatures. The experimentally measured rotational temperature at the gas-liquid interface is 870 K from the Nz（C-B） band with a power input of 26 W. With the prolongation of the discharge time, significant changes in the discharge voltage and current, discharge emission patterns, instantaneous concentrations of the secondary species （e.g., H202, NO2, and NO3） in the liquid phase, pH values and electrical conductivities of the liquids are observed experimentally. The present study is helpful for deepening the understandings to the basic physical-chemical processes in the discharges in contact with liquids, especially to those occurring in the vicinity of the gas-liquid interface, and also for promoting existing and potential applications of such type of discharges in the fields of environmental protection, biomedicine, agriculture, and so on.展开更多
From energy generation to transportation, from energy distribution to storage, from semiconductor processing to communications, and from portable devices to data centers, energy consumption has grown to be a major lim...From energy generation to transportation, from energy distribution to storage, from semiconductor processing to communications, and from portable devices to data centers, energy consumption has grown to be a major limitation to usability and performance. Therefore, energy-efficient technologies become an active research area motivated by energy necessity and environmental concerns. With energy-efficient technologies, a number of epoch-making technical approaches can be expected. Energy efficiency technologies are affecting all forms of energy conversion and all aspects of life.展开更多
We conduct a survival analysis for the viewing durations of massive open online courses.The hazard function of the empirical duration data presents as a bathtub curve with the Lindy effect in its tail.To understand th...We conduct a survival analysis for the viewing durations of massive open online courses.The hazard function of the empirical duration data presents as a bathtub curve with the Lindy effect in its tail.To understand the evolutionary mechanisms underlying these features,we categorize learners into two classes based on their different distributions of viewing durations,namely lognormal distribution and power law with exponential cutoff.Two random differential equations are provided to describe the growth patterns of viewing durations for the two classes respectively.The expected duration change rate of the learners featured by lognormal distribution is supposed to be dependent on their past duration,and that of the remainder of learners is supposed to be inversely proportional to time.Solutions to the equations predict the features of viewing duration distributions,and those of the hazard function.The equations also reveal the features of memory and memorylessness for the respective viewing behaviors of the two classes.展开更多
The traditional student-oriented course evaluation has been the major assessment method on teaching effectiveness worldwide.Useful as it is,it has been widely and continuously criticized for not being a fair,accurate,...The traditional student-oriented course evaluation has been the major assessment method on teaching effectiveness worldwide.Useful as it is,it has been widely and continuously criticized for not being a fair,accurate,and reliable measurement.In search of a more objective assessment method on teaching effectiveness that also reflects the impacts of context-based learning,we propose a theoretical approach from a unique perspective that recognizes teaching effectiveness as a result of the interplays between teacher,student,and context.The approach can be used to compute as well as to predict teaching effectiveness using machine and deep learning technologies,which brings strategical benefits to institutional management.In addition,we install into the approach a mechanism using tokens as incentives to assure the quality of subjective data input.The application framework for the approach is proposed leveraging blockchain.Each implementation of the framework by an establishment is a decentralized application that runs on its chosen blockchain.It is envisioned that the implementations together will form a collective ecology on context-based relative teaching effectiveness,which has the potential to fundamentally impact other academic practices besides teaching effectiveness measurement.The theoretical approach provides a common language to delineate teaching effectiveness from the context-based relative perspective and is customizable during implementation.The teaching effectiveness assessment using the approach downplays the roles played by bias(subjectity)and hence is more objective than that by traditional student-oriented course evaluation.展开更多
Nuclear technique is a powerful scientific tool in agricultural research, an area with fruitful achievements in China. Application of nuclear technique in agriculture (Nuclear Agricultural Sciences) based on the devel...Nuclear technique is a powerful scientific tool in agricultural research, an area with fruitful achievements in China. Application of nuclear technique in agriculture (Nuclear Agricultural Sciences) based on the development of related science and technology is a high-tech area, and also a significant aspect of non-electrical power application of nuclear technique. As an important component of agricultural science and technology, Nuclear technique application in agricultural field has achieved a lot and made remarkable contributions to the economic, social and ecological development of China. The current paper reviews the achievements, and presents the situation of the application of nuclear technique in the Chinese a-griculture briefly. The author strongly suggests that Chinese government should pay more attention to the study on the application of nuclear technique in agriculture, in order to promote its development and contribute more to the Chinese society and agriculture.展开更多
文摘Inductively-coupled plasma mass spectrometry (ICP-MS) has made much progress since its birth in the late 1990s. This paper will give a rather systematic overview on the use of this technique in new devices and technologies related to plasma source, sample-introducing device and detecting spectrometer etc. In this overview, an emphasis will be put on the evaluation of the ICP- MS technique in combination with a series of physical, chemical and biological techniques, such as laser ablation (LA), capillary electrophoresis (CE) and high performance liquid chromatograph (HPLC), along with their representative high accuracy and high sensitivity. Finally, comprehensive and fruitful applications of the ICP-MS and its combinative techniques in the detection of trace metallic elements and isotopes in complex biological and environmental samples will be revealed.
文摘Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applications. The Terahertz region has been the focus of research worldwide since early 1990s. Due to their unique characteristics, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, and biomedical imaging.
文摘Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applications. The Terahertz region has been the focus of research worldwide since early 1990s. Due to their unique characteristics, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, and biomedical imaging.
文摘Terahertz waves, sitting in the gap between the middle infrared and millimeter wave regions, are known as the last vacant area of the electromagnetic spectrum that has not quite been understood and brought into applications. The Terahertz region has been the focus of research worldwide since early 1990s. Due to their unique characteristics, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, and biomedical imaging.
文摘Terahertz wave, sitting in the gap between middle infrared and millimeter wave, has been known as the last vacant area in spectrum that has not been quite understood and brought into applications. It has been the focus of research worldwide since early 1990s. Due to the unique characteristics of Terahertz wave, Terahertz technologies have a wide range of applications, such as hazard detection, high speed data communications, radio astronomy, biomedical imaging, etc.
文摘In this paper expressions for the solution and general properties (wave energy, radiation stress, etc.) of the first-order cnoidal wave theory are given as a power series of the complementary modulus of the theta function. These expressions are convenient for numerical calculation because they converge very rapidly over the applicable range of Ursell number (Us> 10) for the theory. As examples of practical application, the relative height of wave crest, maximum bottom velocity, radiation stress, wave set-down and set-up are calculated. Comparisons between calculated values and experimental data are made.
文摘Online education has attracted a large number of students in recent years, because it breaks through the limitations of time and space and makes high-quality education at your fingertips. The method of predicting student performance is to analyze and predict the student’s final performance by collecting demographic data such as the student’s gender, age, and highest education level, and clickstream data generated when students interact with VLE in different types of specific courses, which are widely used in online education platforms. This article proposes a model to predict student performance via Attention-based Multi-layer LSTM (AML), which combines student demographic data and clickstream data for comprehensive analysis. We hope that we can obtain a higher prediction accuracy as soon as possible to provide timely intervention. The results show that the proposed model can improve the accuracy of 0.52% - 0.85% and the F1 score of 0.89% - 2.30% on the four-class classification task as well as the accuracy of 0.15% - 0.97% and the F1 score of 0.21% - 2.77% on the binary classification task from week 5 to week 25.
文摘This article firstly explains the concepts of artificial intelligence and algorithm separately,then determines the research status of artificial intelligence and machine learning in the background of the increasing popularity of artificial intelligence,and finally briefly describes the machine learning algorithm in the field of artificial intelligence,as well as puts forward appropriate development prospects,in order to provide theoretical reference for industry insider.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No.2014ZX07215-001)partly by National Natural Science Foundation of China(Nos.11475103,51578309)the Chinese Scholarship Council for the financial assistance of my PhD program in Tsinghua University of China
文摘In this paper, the AC-excited helium discharges generated between the powered needle electrode enclosed in a conical quartz tube and the grounded de-ionized water electrode are investigated. The current and voltage waveforms exhibit a transition from the glow-like to streamer-like mode discharges, which forms a stable cone-shaped structure at the gas-liquid interface. In this region, the air and water vapor diffusion initiate various physical-chemical processes leading to substantial changes of the primary species emission intensities （e.g., OH, N2, NO, and O） and the rotational temperatures. The experimentally measured rotational temperature at the gas-liquid interface is 870 K from the Nz（C-B） band with a power input of 26 W. With the prolongation of the discharge time, significant changes in the discharge voltage and current, discharge emission patterns, instantaneous concentrations of the secondary species （e.g., H202, NO2, and NO3） in the liquid phase, pH values and electrical conductivities of the liquids are observed experimentally. The present study is helpful for deepening the understandings to the basic physical-chemical processes in the discharges in contact with liquids, especially to those occurring in the vicinity of the gas-liquid interface, and also for promoting existing and potential applications of such type of discharges in the fields of environmental protection, biomedicine, agriculture, and so on.
文摘From energy generation to transportation, from energy distribution to storage, from semiconductor processing to communications, and from portable devices to data centers, energy consumption has grown to be a major limitation to usability and performance. Therefore, energy-efficient technologies become an active research area motivated by energy necessity and environmental concerns. With energy-efficient technologies, a number of epoch-making technical approaches can be expected. Energy efficiency technologies are affecting all forms of energy conversion and all aspects of life.
基金supported by the National Natural Science Foundation of China (No. 61773020)the National Education Science Foundation of China (No. DIA180383)
文摘We conduct a survival analysis for the viewing durations of massive open online courses.The hazard function of the empirical duration data presents as a bathtub curve with the Lindy effect in its tail.To understand the evolutionary mechanisms underlying these features,we categorize learners into two classes based on their different distributions of viewing durations,namely lognormal distribution and power law with exponential cutoff.Two random differential equations are provided to describe the growth patterns of viewing durations for the two classes respectively.The expected duration change rate of the learners featured by lognormal distribution is supposed to be dependent on their past duration,and that of the remainder of learners is supposed to be inversely proportional to time.Solutions to the equations predict the features of viewing duration distributions,and those of the hazard function.The equations also reveal the features of memory and memorylessness for the respective viewing behaviors of the two classes.
基金The work in this paper is jointly funded by Tianjin Municipality Natural Science Foundation(18JCYBJC44500)the National Social Science Foundation of China(No.20BTQ084).
文摘The traditional student-oriented course evaluation has been the major assessment method on teaching effectiveness worldwide.Useful as it is,it has been widely and continuously criticized for not being a fair,accurate,and reliable measurement.In search of a more objective assessment method on teaching effectiveness that also reflects the impacts of context-based learning,we propose a theoretical approach from a unique perspective that recognizes teaching effectiveness as a result of the interplays between teacher,student,and context.The approach can be used to compute as well as to predict teaching effectiveness using machine and deep learning technologies,which brings strategical benefits to institutional management.In addition,we install into the approach a mechanism using tokens as incentives to assure the quality of subjective data input.The application framework for the approach is proposed leveraging blockchain.Each implementation of the framework by an establishment is a decentralized application that runs on its chosen blockchain.It is envisioned that the implementations together will form a collective ecology on context-based relative teaching effectiveness,which has the potential to fundamentally impact other academic practices besides teaching effectiveness measurement.The theoretical approach provides a common language to delineate teaching effectiveness from the context-based relative perspective and is customizable during implementation.The teaching effectiveness assessment using the approach downplays the roles played by bias(subjectity)and hence is more objective than that by traditional student-oriented course evaluation.
文摘Nuclear technique is a powerful scientific tool in agricultural research, an area with fruitful achievements in China. Application of nuclear technique in agriculture (Nuclear Agricultural Sciences) based on the development of related science and technology is a high-tech area, and also a significant aspect of non-electrical power application of nuclear technique. As an important component of agricultural science and technology, Nuclear technique application in agricultural field has achieved a lot and made remarkable contributions to the economic, social and ecological development of China. The current paper reviews the achievements, and presents the situation of the application of nuclear technique in the Chinese a-griculture briefly. The author strongly suggests that Chinese government should pay more attention to the study on the application of nuclear technique in agriculture, in order to promote its development and contribute more to the Chinese society and agriculture.
