The changes in knowledge forms in the era of"new quality productivity"are closely related to the development of society.With the rise of the Internet,"the world of dataism is coming".The traditiona...The changes in knowledge forms in the era of"new quality productivity"are closely related to the development of society.With the rise of the Internet,"the world of dataism is coming".The traditional knowledge production model is undergoing fundamental changes in structure and nature.The most prominent change is that knowledge is becoming increasingly inseparable from data networks.The collaborative production of knowledge based on the Internet is becoming increasingly common,and Wikipedia is a prominent example of this.Wikipedia makes the networked production of knowledge possible by utilizing collective intelligence and data connectivity.Wiki users are commonly referred to as"wiki".This paper conducted interviews with 30 Wiki users and used content analysis to statistically analyze the interview records,in order to study the significance and value of the Wiki knowledge production model for online users,and to glimpse the impact of the knowledge structure changes in the era of"dataism"on social change.展开更多
The investigation endorsed the convective flow of Carreau nanofluid over a stretched surface in presence of entropy generation optimization.The novel dynamic of viscous dissipation is utilized to analyze the thermal m...The investigation endorsed the convective flow of Carreau nanofluid over a stretched surface in presence of entropy generation optimization.The novel dynamic of viscous dissipation is utilized to analyze the thermal mechanism of magnetized flow.The convective boundary assumptions are directed in order to examine the heat and mass transportation of nanofluid.The thermal concept of thermophoresis and Brownian movements has been re-called with the help of Buongiorno model.The problem formulated in dimensionless form is solved by NDSolve MATHEMATICA.The graphical analysis for parameters governed by the problem is performed with physical applications.The affiliation of entropy generation and Bejan number for different parameters is inspected in detail.The numerical data for illustrating skin friction,heat and mass transfer rate is also reported.The motion of the fluid is highest for the viscosity ratio parameter.The temperature of the fluid rises via thermal Biot number.Entropy generation rises for greater Brinkman number and diffusion parameter.展开更多
With the rapid development of technology and economy,the demand for energy in society is increasing.People are gradually realizing that fossil energy is limited,and the development of new energy may also face situatio...With the rapid development of technology and economy,the demand for energy in society is increasing.People are gradually realizing that fossil energy is limited,and the development of new energy may also face situations where it cannot meet social needs.The problem of resource shortage is gradually exposed to people.Therefore,the development of usable new energy has become an urgent problem for society to solve.At present,electricity is the most widely used energy source worldwide and photovoltaic power generation technology is gradually becoming well-known.As an emerging industry,the development of photovoltaic power generation still requires continuous promotion by national and social policies to be extended to various industries and ensure the stability of its energy supply.This article mainly outlines the principles,characteristics,and advantages of photovoltaic power generation,and briefly explains the current technology types and application aspects of photovoltaic power generation to contribute to its promotion and better serve all aspects of social life with new energy.展开更多
The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centenni...The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centennial goal.At the 19th National Congress,it was put forward by the country that the concept of“new generation of the times”for the first time,indicating the training direction and theoretical guidance for the new generation of the times.The new age requires young people to have firm ideals and beliefs,excellent skills,and a great spirit of responsibility.The proposition of cultivating a new generation of the times is a deep exploration and summary of Marx’s theory of“all-round human development,”Lenin’s youth view and the education view of excellent traditional Chinese culture,and the proposition needs to strengthen the leadership of the Party,give play to the leading role of socialist core values,and the youth themselves should actively act to realize the transformation of theoretical and practical results.展开更多
Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the developm...Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the development of new practical applications in photonics,lasing,and sensing.Here,we employ symmetry-broken metasurfaces made of centrosymmetric amorphous silicon for resonantly enhanced second-and third-order nonlinear optical response.Exploiting the rich physics of optical quasi-bound states in the continuum and guided mode resonances,we comprehensively study through rigorous numerical calculations the relative contribution of surface and bulk effects to second-harmonic generation(SHG)and the bulk contribution to third-harmonic generation(THG) from the meta-atoms.Next,we experimentally achieve optical resonances with high quality factors,which greatly boosts light-matter interaction,resulting in about 550 times SHG enhancement and nearly 5000-fold increase of THG.A good agreement between theoretical predictions and experimental measurements is observed.To gain deeper insights into the physics of the investigated nonlinear optical processes,we further numerically study the relation between nonlinear emission and the structural asymmetry of the metasurface and reveal that the generated harmonic signals arising from linear sharp resonances are highly dependent on the asymmetry of the meta-atoms.Our work suggests a fruitful strategy to enhance the harmonic generation and effectively control different orders of harmonics in all-dielectric metasurfaces,enabling the development of efficient active photonic nanodevices.展开更多
Measurement of bloodflow velocity is key to understanding physiology and pathology in vivo.While most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the in...Measurement of bloodflow velocity is key to understanding physiology and pathology in vivo.While most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the instantaneous bloodflow velocity distribution.This is mainly due to the lack of measurement technology with high spatial and temporal resolution.Here,we tackle this problem with our recently developed dual-wavelength line-scan third-harmonic generation(THG)imaging technology.Simultaneous acquisition of dual-wavelength THG line-scanning signals enables measurement of bloodflow velocities at two radially symmetric positions in both venules and arterioles in mouse brain in vivo.Our results clearly show that the instantaneous bloodflow velocity is not symmetric under general conditions.展开更多
Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks.Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition,high total organ...Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks.Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition,high total organic carbon(TOC)content,various kerogen types,and a wide range of thermal maturity.Consequently,their hydrocarbon generation potential and resource estimation can be misinterpreted.In this study,geochemical tests,numerical analysis,hydrocarbon generation kinetics,and basin modeling were integrated to investigate the differential effects of kerogen types on the hydrocarbon generation potential of lacustrine source rocks.Optimized hydrocarbon generation and expulsion(HGE)models of different kerogen types were established quantitatively upon abundant Rock-Eval/TOC/vitrinite reflectance(R_(o))datasets.Three sets of good-excellent source rocks deposited in the fourth(Es4),third(Es3),and first(Es1)members of Paleogene Shahejie Formation,are predominantly types I-II_(1),II_(1)-II_(2),and II-III,respectively.The activation energy of types I-II_(2)kerogen is concentrated(180-230 kcal/mol),whereas that of type III kerogen is widely distributed(150-280 kcal/mol).The original hydrocarbon generation potentials of types I,II_(1),II_(2),and III kerogens are 790,510,270,and 85 mg/g TOC,respectively.The Ro values of the hydrocarbon generation threshold for type I-III source rocks gradually increase from 0.42%to 0.74%,and Ro values of the hydrocarbon expulsion threshold increase from 0.49%to 0.87%.Types I and II_(1)source rocks are characterized by earlier hydrocarbon generation,more rapid hydrocarbon expulsion,and narrower hydrocarbon generation windows than types II_(2)and III source rocks.The kerogen types also affect the HGE history and resource potential.Three types(conventional,tight,and shale oil/gas)and three levels(realistic,expected,and prospective)of hydrocarbon resources of different members in the Liaohe Western Depression are evaluated.Findings suggest that the Es3 member has considerable conventional and unconventional hydrocarbon resources.This study can quantitatively characterize the hydrocarbon generation potential of source rocks with different kerogen types,and facilitate a quick and accurate assessment of hydrocarbon resources,providing strategies for future oil and gas exploration.展开更多
The corrosion rate is a crucial factor that impacts the longevity of materials in different applications.After undergoing friction stir processing(FSP),the refined grain structure leads to a notable decrease in corros...The corrosion rate is a crucial factor that impacts the longevity of materials in different applications.After undergoing friction stir processing(FSP),the refined grain structure leads to a notable decrease in corrosion rate.However,a better understanding of the correlation between the FSP process parameters and the corrosion rate is still lacking.The current study used machine learning to establish the relationship between the corrosion rate and FSP process parameters(rotational speed,traverse speed,and shoulder diameter)for WE43 alloy.The Taguchi L27 design of experiments was used for the experimental analysis.In addition,synthetic data was generated using particle swarm optimization for virtual sample generation(VSG).The application of VSG has led to an increase in the prediction accuracy of machine learning models.A sensitivity analysis was performed using Shapley Additive Explanations to determine the key factors affecting the corrosion rate.The shoulder diameter had a significant impact in comparison to the traverse speed.A graphical user interface(GUI)has been created to predict the corrosion rate using the identified factors.This study focuses on the WE43 alloy,but its findings can also be used to predict the corrosion rate of other magnesium alloys.展开更多
The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayto...The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy.Parametric analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes.Results show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic performance.Among the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to optimization.The performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,respectively.The performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited funds.For the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.展开更多
Unlike the traditional traction power supply system which enables the electrified railway traction sub- station to be connected to power grid in a way of phase rotation, a new generation traction power supply system w...Unlike the traditional traction power supply system which enables the electrified railway traction sub- station to be connected to power grid in a way of phase rotation, a new generation traction power supply system without phase splits is proposed in this paper. Three key techniques used in this system have been discussed. First, a combined co-phase traction power supply system is applied at traction substations for compensating negative sequence current and eliminating phase splits at exits of substations; design method and procedure for this system are presented. Second, a new bilateral traction power supply technology is proposed to eliminate the phase split at section post and reduce the influence of equalizing current on the power grid. Meanwhile, power factor should be adjusted to ensure a proper voltage level of the traction network. Third, a seg- mental power supply technology of traction network is used to divide the power supply arms into several segments, and the synchronous measurement and control technology is applied to diagnose faults and their locations quickly and accurately. Thus, the fault impact can be limited to a min- imum degree. In addition, the economy and reliability of the new generation traction power supply system are analyzed.展开更多
This article expounds the necessity of the transformation from traditional farmers to modern new farmers: the building of new socialist countryside needs modern new farmers; the coordination of urban-rural integration...This article expounds the necessity of the transformation from traditional farmers to modern new farmers: the building of new socialist countryside needs modern new farmers; the coordination of urban-rural integration development needs the transformation from traditional farmers to modern new farmers; the development of modern agriculture needs the transformation from traditional farmers to modern new farmers. Then it analyses the characteristics and role of new-generation farmers, and presents the way to accelerate cultivation of new-generation farmers: make sound laws and regulations, to lay solid foundation for cultivation of new-generation farmers; create conditions, to provide funds guarantee for cultivation of new-generation farmers; make scientific planning, to promote regular, systematized and standardized training work for new-generation farmers; focus on education, to promote the overall quality of new-generation farmers; innovate upon content, to meet the needs of development of new-generation farmers; highlight focus, to intensify competitiveness training for returning-home migrant workers.展开更多
The issue concerning new generation migrant workers is an important part of current social management. How to improve employment ability of new generation migrant workers is the central part of improving living of mig...The issue concerning new generation migrant workers is an important part of current social management. How to improve employment ability of new generation migrant workers is the central part of improving living of migrant workers and development environment. Based on survey data of 6 counties in Hubei Province,I analyzed employment will and influence factors of new generation migrant workers. Researches have indicated that going out to work,employment opportunity,nature of subordinate service industry,industrial technical level,and financial support play a significant role in employment intention of migrant workers,while their employment ability is influenced by their cultural quality,professional skills, working endurance,degree of policy cognition,and information channel,etc. In view of these five aspects,I put forward following countermeasures: raise educational level,improve skills,strengthen endurance,enhance attention to policies,and expand information channel,to improve employment ability of new generation migrant workers.展开更多
The paper conducts an investigation on the new generation migrant workers in view of the selecting and obtaining employment of new generation migrant workers in industrial zone of Yudu County,Ganzhou Province during t...The paper conducts an investigation on the new generation migrant workers in view of the selecting and obtaining employment of new generation migrant workers in industrial zone of Yudu County,Ganzhou Province during the period from June 23,2010 to June 27,2010.The basic situation of the selecting and obtaining employment of new generation migrant workers,the expectation and career goals is collected.The chief problems confronted by the selecting and obtaining employment of migrant workers are analyzed.The problems cover substandard employment of enterprises;unsatisfying working and living conditions of new generation migrant workers;the knowledge and technology of new generation migrant workers lag behind the demand of enterprises;the new generation migrant workers lack the spirit of bearing hardships and hard work;new generation migrant workers do not have clear career plan and their demands on studying and training are hard to be materialized;restricted by household registration system,the new generation migrant workers can not enter into their workplace.Countermeasures and suggestions on solving the selecting and obtaining of new generation migrant workers are put forward.Firstly,perfecting the relevant laws and regulations on labors and protecting the each item of labor economic rights of new generation migrant workers;secondly,intensifying vocational training and improving the competitiveness of new generation migrant workers;thirdly,paying attention to the political education and mental health education on new generation migrant workers and launching rich and colorful cultural activities;fourthly,reinforcing the human concern and right protection on new generation migrant workers to enhance their right to say;fifthly,intensifying the reform on household registration and accelerating the process of urbanization.展开更多
With urbanization and socio-economic development,new generation migrant workers play an increasingly important role in urban construction. However,for a long time,their social integration situation in inflow places is...With urbanization and socio-economic development,new generation migrant workers play an increasingly important role in urban construction. However,for a long time,their social integration situation in inflow places is not ideal. Academic circle has done a lot of researches,but no effective strategy is so far put forward. Through analysis of domestic and foreign researches,it is found that social capital and human capital have an important influence on social integration of new generation migrant workers. This paper takes this as starting point,combines characteristics of new generation migrant workers,and overviews theories and empirical researches of domestic and foreign famous scholars,to explore the relationship between social capital and human capital and social integration of new generation migrant workers.展开更多
Sum frequency generation vibrational spectroscopy (SFG-VS) is a robust technique for inter- facial investigation at molecular level. The performance of SFG-VS mostly depends on the spectral resolution of the SFG sys...Sum frequency generation vibrational spectroscopy (SFG-VS) is a robust technique for inter- facial investigation at molecular level. The performance of SFG-VS mostly depends on the spectral resolution of the SFG system. In this research, a simplified function was deduced to calculate the spectral resolution of picosecond SFG system and the lineshape of SFG spectra based on the Guassian shaped functions of IR beam and visible beam. The function indicates that the lineshpe of SFG spectra from nonresonant samples can be calculated by the Guassian widths of both IR beam and visible beam. And the Voigt lineshape of SFG spectra from vibrational resonant samples can be calculated by the Homogeneous broadening (Lorentzian width) and Inhomogeneous broadening (Guassian width) of vibrational modes, as well as the Guassian widths of both IR beam and visible beam. Such functions were also applied to verify the spectral resolution of the polarization-resolved and frequency-resolved picosecond SFG-VS system which was developed by our group recently. It is shown that the linewidths of IR beams that generated from current laser system are about 1.5 cm-1. The calculated spectral resolution of current picosecond IR scanning SFG-VS system is about 4.6 cm-1, which is consist with he spctral resolution shown in the spectra of cholesterol monolayer (3.5-5 cm-1).展开更多
From the perspective of life cycle assessment (LCA), the development, construction, and operation of all kinds of new energy power generation technologies release greenhouse gas (GHG) emissions. This sparks concer...From the perspective of life cycle assessment (LCA), the development, construction, and operation of all kinds of new energy power generation technologies release greenhouse gas (GHG) emissions. This sparks concerns about the lowcarbon nature of the new energy power generation technologies. Based on national and international literature review, this paper estimates and compares the GHG emission factors of traditional thermal power generation and new energy power generation technologies in China with the LCA approach. The GHG mitigation potential of new energy power generation technologies as substitution for traditional thermal power generation in China was evaluated, according to the objectives of new energy power generation of the national development planning. The results show that the GHG emission factors of new energy power generation axe much lower than that of traditional thermal power generation even with LCA accounting, and the GHG mitigation potential of new energy substitution is huge.展开更多
With the development of carbon electricity,achieving a low-carbon economy has become a prevailing and inevitable trend.Improving low-carbon expansion generation planning is critical for carbon emission mitigation and ...With the development of carbon electricity,achieving a low-carbon economy has become a prevailing and inevitable trend.Improving low-carbon expansion generation planning is critical for carbon emission mitigation and a lowcarbon economy.In this paper,a two-layer low-carbon expansion generation planning approach considering the uncertainty of renewable energy at multiple time scales is proposed.First,renewable energy sequences considering the uncertainty in multiple time scales are generated based on the Copula function and the probability distribution of renewable energy.Second,a two-layer generation planning model considering carbon trading and carbon capture technology is established.Specifically,the upper layer model optimizes the investment decision considering the uncertainty at a monthly scale,and the lower layer one optimizes the scheduling considering the peak shaving at an hourly scale and the flexibility at a 15-minute scale.Finally,the results of different influence factors on low-carbon generation expansion planning are compared in a provincial power grid,which demonstrate the effectiveness of the proposed model.展开更多
Through literature research and expert interviews,we extract 10 variables influencing the new generation migrant workers' employability,and establish the comprehensive evaluation model of the new generation migran...Through literature research and expert interviews,we extract 10 variables influencing the new generation migrant workers' employability,and establish the comprehensive evaluation model of the new generation migrant workers' employability. Using factor analysis,we derive that the model includes three factors: skill literacy,relationship literacy and basic literacy. The weights of each factor are 0. 580,0. 244 and 0. 174 8,respectively. Skill literacy is affected by skill level,learning ability,career aspiration,ability to analyze problems,physical health status and other factors. Relationship literacy is affected by the sense of teamwork,interpersonal skills,social support and other factors. Basic literacy is affected by educational level,hardworking spirit and other factors. According to the results,we put forth the following recommendations to improve the new generation migrant workers' employability: strengthening the vocational skill training; coordinating the vocational education resources.展开更多
Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity grad...Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing electricity.However,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG simultaneously.Herein,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from TSG.It enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam generation.Meanwhile,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity generation.These benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high voltage.Directly interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity supply.It produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.展开更多
Based on survey data of current situations of new generation migrant workers vocational education and its influence on social mobility in Shijiazhuang City, the author believes that there are many drawbacks in vocatio...Based on survey data of current situations of new generation migrant workers vocational education and its influence on social mobility in Shijiazhuang City, the author believes that there are many drawbacks in vocational education of new generation migrant workers, including low participationt and varied training environment of enterprises. In addition, the influence of vocational education of migrant workers on social mobility is not very satisfactory. Finally, it presents countermeasures for improving vocational education, to promote social mobility of new generation migrant workers.展开更多
基金Supported by Major Project of National Social Science Fund of China(19ZDA326).
文摘The changes in knowledge forms in the era of"new quality productivity"are closely related to the development of society.With the rise of the Internet,"the world of dataism is coming".The traditional knowledge production model is undergoing fundamental changes in structure and nature.The most prominent change is that knowledge is becoming increasingly inseparable from data networks.The collaborative production of knowledge based on the Internet is becoming increasingly common,and Wikipedia is a prominent example of this.Wikipedia makes the networked production of knowledge possible by utilizing collective intelligence and data connectivity.Wiki users are commonly referred to as"wiki".This paper conducted interviews with 30 Wiki users and used content analysis to statistically analyze the interview records,in order to study the significance and value of the Wiki knowledge production model for online users,and to glimpse the impact of the knowledge structure changes in the era of"dataism"on social change.
文摘The investigation endorsed the convective flow of Carreau nanofluid over a stretched surface in presence of entropy generation optimization.The novel dynamic of viscous dissipation is utilized to analyze the thermal mechanism of magnetized flow.The convective boundary assumptions are directed in order to examine the heat and mass transportation of nanofluid.The thermal concept of thermophoresis and Brownian movements has been re-called with the help of Buongiorno model.The problem formulated in dimensionless form is solved by NDSolve MATHEMATICA.The graphical analysis for parameters governed by the problem is performed with physical applications.The affiliation of entropy generation and Bejan number for different parameters is inspected in detail.The numerical data for illustrating skin friction,heat and mass transfer rate is also reported.The motion of the fluid is highest for the viscosity ratio parameter.The temperature of the fluid rises via thermal Biot number.Entropy generation rises for greater Brinkman number and diffusion parameter.
文摘With the rapid development of technology and economy,the demand for energy in society is increasing.People are gradually realizing that fossil energy is limited,and the development of new energy may also face situations where it cannot meet social needs.The problem of resource shortage is gradually exposed to people.Therefore,the development of usable new energy has become an urgent problem for society to solve.At present,electricity is the most widely used energy source worldwide and photovoltaic power generation technology is gradually becoming well-known.As an emerging industry,the development of photovoltaic power generation still requires continuous promotion by national and social policies to be extended to various industries and ensure the stability of its energy supply.This article mainly outlines the principles,characteristics,and advantages of photovoltaic power generation,and briefly explains the current technology types and application aspects of photovoltaic power generation to contribute to its promotion and better serve all aspects of social life with new energy.
文摘The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centennial goal.At the 19th National Congress,it was put forward by the country that the concept of“new generation of the times”for the first time,indicating the training direction and theoretical guidance for the new generation of the times.The new age requires young people to have firm ideals and beliefs,excellent skills,and a great spirit of responsibility.The proposition of cultivating a new generation of the times is a deep exploration and summary of Marx’s theory of“all-round human development,”Lenin’s youth view and the education view of excellent traditional Chinese culture,and the proposition needs to strengthen the leadership of the Party,give play to the leading role of socialist core values,and the youth themselves should actively act to realize the transformation of theoretical and practical results.
基金supported by the Australian Research Council(Grant No.DP210101292)the International Technology Center Indo-Pacific (ITC IPAC) via Army Research Office (contract FA520923C0023)。
文摘Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the development of new practical applications in photonics,lasing,and sensing.Here,we employ symmetry-broken metasurfaces made of centrosymmetric amorphous silicon for resonantly enhanced second-and third-order nonlinear optical response.Exploiting the rich physics of optical quasi-bound states in the continuum and guided mode resonances,we comprehensively study through rigorous numerical calculations the relative contribution of surface and bulk effects to second-harmonic generation(SHG)and the bulk contribution to third-harmonic generation(THG) from the meta-atoms.Next,we experimentally achieve optical resonances with high quality factors,which greatly boosts light-matter interaction,resulting in about 550 times SHG enhancement and nearly 5000-fold increase of THG.A good agreement between theoretical predictions and experimental measurements is observed.To gain deeper insights into the physics of the investigated nonlinear optical processes,we further numerically study the relation between nonlinear emission and the structural asymmetry of the metasurface and reveal that the generated harmonic signals arising from linear sharp resonances are highly dependent on the asymmetry of the meta-atoms.Our work suggests a fruitful strategy to enhance the harmonic generation and effectively control different orders of harmonics in all-dielectric metasurfaces,enabling the development of efficient active photonic nanodevices.
基金funded by the National Natural Science Foundation of China(Grant/Award Numbers 62075135 and 61975126)the Science and Technology Innovation Commission of Shenzhen(Grant/Award Numbers JCYJ20190808174819083 and JCYJ20190808175201640)Shenzhen Science and Technology Planning Project(ZDSYS 20210623092006020).
文摘Measurement of bloodflow velocity is key to understanding physiology and pathology in vivo.While most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the instantaneous bloodflow velocity distribution.This is mainly due to the lack of measurement technology with high spatial and temporal resolution.Here,we tackle this problem with our recently developed dual-wavelength line-scan third-harmonic generation(THG)imaging technology.Simultaneous acquisition of dual-wavelength THG line-scanning signals enables measurement of bloodflow velocities at two radially symmetric positions in both venules and arterioles in mouse brain in vivo.Our results clearly show that the instantaneous bloodflow velocity is not symmetric under general conditions.
基金This research is supported by the Joint Fund of the National Natural Science Foundation of China(grant number U19B6003-02)the Cooperation Program of PetroChina Liaohe Oilfield Company(grant Number HX20180604)the AAPG Foundation Grants-in-Aid Program(grant number 22269437).This study has benefited considerably from PetroChina Liaohe Oilfield Company for data support.We also thank the editor and the anonymous reviewers for their professional suggestions and comments.
文摘Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks.Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition,high total organic carbon(TOC)content,various kerogen types,and a wide range of thermal maturity.Consequently,their hydrocarbon generation potential and resource estimation can be misinterpreted.In this study,geochemical tests,numerical analysis,hydrocarbon generation kinetics,and basin modeling were integrated to investigate the differential effects of kerogen types on the hydrocarbon generation potential of lacustrine source rocks.Optimized hydrocarbon generation and expulsion(HGE)models of different kerogen types were established quantitatively upon abundant Rock-Eval/TOC/vitrinite reflectance(R_(o))datasets.Three sets of good-excellent source rocks deposited in the fourth(Es4),third(Es3),and first(Es1)members of Paleogene Shahejie Formation,are predominantly types I-II_(1),II_(1)-II_(2),and II-III,respectively.The activation energy of types I-II_(2)kerogen is concentrated(180-230 kcal/mol),whereas that of type III kerogen is widely distributed(150-280 kcal/mol).The original hydrocarbon generation potentials of types I,II_(1),II_(2),and III kerogens are 790,510,270,and 85 mg/g TOC,respectively.The Ro values of the hydrocarbon generation threshold for type I-III source rocks gradually increase from 0.42%to 0.74%,and Ro values of the hydrocarbon expulsion threshold increase from 0.49%to 0.87%.Types I and II_(1)source rocks are characterized by earlier hydrocarbon generation,more rapid hydrocarbon expulsion,and narrower hydrocarbon generation windows than types II_(2)and III source rocks.The kerogen types also affect the HGE history and resource potential.Three types(conventional,tight,and shale oil/gas)and three levels(realistic,expected,and prospective)of hydrocarbon resources of different members in the Liaohe Western Depression are evaluated.Findings suggest that the Es3 member has considerable conventional and unconventional hydrocarbon resources.This study can quantitatively characterize the hydrocarbon generation potential of source rocks with different kerogen types,and facilitate a quick and accurate assessment of hydrocarbon resources,providing strategies for future oil and gas exploration.
文摘The corrosion rate is a crucial factor that impacts the longevity of materials in different applications.After undergoing friction stir processing(FSP),the refined grain structure leads to a notable decrease in corrosion rate.However,a better understanding of the correlation between the FSP process parameters and the corrosion rate is still lacking.The current study used machine learning to establish the relationship between the corrosion rate and FSP process parameters(rotational speed,traverse speed,and shoulder diameter)for WE43 alloy.The Taguchi L27 design of experiments was used for the experimental analysis.In addition,synthetic data was generated using particle swarm optimization for virtual sample generation(VSG).The application of VSG has led to an increase in the prediction accuracy of machine learning models.A sensitivity analysis was performed using Shapley Additive Explanations to determine the key factors affecting the corrosion rate.The shoulder diameter had a significant impact in comparison to the traverse speed.A graphical user interface(GUI)has been created to predict the corrosion rate using the identified factors.This study focuses on the WE43 alloy,but its findings can also be used to predict the corrosion rate of other magnesium alloys.
基金This work was supported of National Natural Science Foundation of China Fund(No.52306033)State Key Laboratory of Engines Fund(No.SKLE-K2022-07)the Jiangxi Provincial Postgraduate Innovation Special Fund(No.YC2022-s513).
文摘The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy.Parametric analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes.Results show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic performance.Among the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to optimization.The performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,respectively.The performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited funds.For the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.
基金supported by the National Natural Science Funds of China (Nos. 51307143 and 51307142)Technology Research and Development Program of China Railway Corporation (No. 2014J009-B)
文摘Unlike the traditional traction power supply system which enables the electrified railway traction sub- station to be connected to power grid in a way of phase rotation, a new generation traction power supply system without phase splits is proposed in this paper. Three key techniques used in this system have been discussed. First, a combined co-phase traction power supply system is applied at traction substations for compensating negative sequence current and eliminating phase splits at exits of substations; design method and procedure for this system are presented. Second, a new bilateral traction power supply technology is proposed to eliminate the phase split at section post and reduce the influence of equalizing current on the power grid. Meanwhile, power factor should be adjusted to ensure a proper voltage level of the traction network. Third, a seg- mental power supply technology of traction network is used to divide the power supply arms into several segments, and the synchronous measurement and control technology is applied to diagnose faults and their locations quickly and accurately. Thus, the fault impact can be limited to a min- imum degree. In addition, the economy and reliability of the new generation traction power supply system are analyzed.
基金Supported by Yunnan Provincial Philosophical Social Science Planning Project (YB2009018)
文摘This article expounds the necessity of the transformation from traditional farmers to modern new farmers: the building of new socialist countryside needs modern new farmers; the coordination of urban-rural integration development needs the transformation from traditional farmers to modern new farmers; the development of modern agriculture needs the transformation from traditional farmers to modern new farmers. Then it analyses the characteristics and role of new-generation farmers, and presents the way to accelerate cultivation of new-generation farmers: make sound laws and regulations, to lay solid foundation for cultivation of new-generation farmers; create conditions, to provide funds guarantee for cultivation of new-generation farmers; make scientific planning, to promote regular, systematized and standardized training work for new-generation farmers; focus on education, to promote the overall quality of new-generation farmers; innovate upon content, to meet the needs of development of new-generation farmers; highlight focus, to intensify competitiveness training for returning-home migrant workers.
基金Supported by Countermeasures for Improvement Employment Will and Ability of New Generation Migrant Workers in Hubei Province ( HBSXK201023)
文摘The issue concerning new generation migrant workers is an important part of current social management. How to improve employment ability of new generation migrant workers is the central part of improving living of migrant workers and development environment. Based on survey data of 6 counties in Hubei Province,I analyzed employment will and influence factors of new generation migrant workers. Researches have indicated that going out to work,employment opportunity,nature of subordinate service industry,industrial technical level,and financial support play a significant role in employment intention of migrant workers,while their employment ability is influenced by their cultural quality,professional skills, working endurance,degree of policy cognition,and information channel,etc. In view of these five aspects,I put forward following countermeasures: raise educational level,improve skills,strengthen endurance,enhance attention to policies,and expand information channel,to improve employment ability of new generation migrant workers.
文摘The paper conducts an investigation on the new generation migrant workers in view of the selecting and obtaining employment of new generation migrant workers in industrial zone of Yudu County,Ganzhou Province during the period from June 23,2010 to June 27,2010.The basic situation of the selecting and obtaining employment of new generation migrant workers,the expectation and career goals is collected.The chief problems confronted by the selecting and obtaining employment of migrant workers are analyzed.The problems cover substandard employment of enterprises;unsatisfying working and living conditions of new generation migrant workers;the knowledge and technology of new generation migrant workers lag behind the demand of enterprises;the new generation migrant workers lack the spirit of bearing hardships and hard work;new generation migrant workers do not have clear career plan and their demands on studying and training are hard to be materialized;restricted by household registration system,the new generation migrant workers can not enter into their workplace.Countermeasures and suggestions on solving the selecting and obtaining of new generation migrant workers are put forward.Firstly,perfecting the relevant laws and regulations on labors and protecting the each item of labor economic rights of new generation migrant workers;secondly,intensifying vocational training and improving the competitiveness of new generation migrant workers;thirdly,paying attention to the political education and mental health education on new generation migrant workers and launching rich and colorful cultural activities;fourthly,reinforcing the human concern and right protection on new generation migrant workers to enhance their right to say;fifthly,intensifying the reform on household registration and accelerating the process of urbanization.
基金Supported by Project of National Social Science Foundation(Grant No.:11CGL072)Project of National Social Science Foundation(Grant No.:11CGL066)+3 种基金Special Fund for Basic Scientific Research of Central Colleges(Grant No.:12MS128)Special Fund for Basic Scientific Research of Central Colleges(Grant No.:12QN34)Project of Baoding City Philosophy andSocial Science Research(Grant No.:201102905)Research Project of Human Resource and Social Security in Hebei Province(Grant No.:JRS-2012-2029)
文摘With urbanization and socio-economic development,new generation migrant workers play an increasingly important role in urban construction. However,for a long time,their social integration situation in inflow places is not ideal. Academic circle has done a lot of researches,but no effective strategy is so far put forward. Through analysis of domestic and foreign researches,it is found that social capital and human capital have an important influence on social integration of new generation migrant workers. This paper takes this as starting point,combines characteristics of new generation migrant workers,and overviews theories and empirical researches of domestic and foreign famous scholars,to explore the relationship between social capital and human capital and social integration of new generation migrant workers.
文摘Sum frequency generation vibrational spectroscopy (SFG-VS) is a robust technique for inter- facial investigation at molecular level. The performance of SFG-VS mostly depends on the spectral resolution of the SFG system. In this research, a simplified function was deduced to calculate the spectral resolution of picosecond SFG system and the lineshape of SFG spectra based on the Guassian shaped functions of IR beam and visible beam. The function indicates that the lineshpe of SFG spectra from nonresonant samples can be calculated by the Guassian widths of both IR beam and visible beam. And the Voigt lineshape of SFG spectra from vibrational resonant samples can be calculated by the Homogeneous broadening (Lorentzian width) and Inhomogeneous broadening (Guassian width) of vibrational modes, as well as the Guassian widths of both IR beam and visible beam. Such functions were also applied to verify the spectral resolution of the polarization-resolved and frequency-resolved picosecond SFG-VS system which was developed by our group recently. It is shown that the linewidths of IR beams that generated from current laser system are about 1.5 cm-1. The calculated spectral resolution of current picosecond IR scanning SFG-VS system is about 4.6 cm-1, which is consist with he spctral resolution shown in the spectra of cholesterol monolayer (3.5-5 cm-1).
基金supported by the China Sustainable Energy Program,Energy Foundation(No.G-0911-11642)Environmental Protection Industry of Commonweal Project "Research on Co-control Policies and Demonstration of Air Pollution and Greenhouse Gas Emissions of Key Industries"(No.201009051)
文摘From the perspective of life cycle assessment (LCA), the development, construction, and operation of all kinds of new energy power generation technologies release greenhouse gas (GHG) emissions. This sparks concerns about the lowcarbon nature of the new energy power generation technologies. Based on national and international literature review, this paper estimates and compares the GHG emission factors of traditional thermal power generation and new energy power generation technologies in China with the LCA approach. The GHG mitigation potential of new energy power generation technologies as substitution for traditional thermal power generation in China was evaluated, according to the objectives of new energy power generation of the national development planning. The results show that the GHG emission factors of new energy power generation axe much lower than that of traditional thermal power generation even with LCA accounting, and the GHG mitigation potential of new energy substitution is huge.
基金supported partly by the National Key R&D Program of China(2018YFA0702200)the Science and Technology Project of State Grid Shandong Electric Power Company(520604190002)。
文摘With the development of carbon electricity,achieving a low-carbon economy has become a prevailing and inevitable trend.Improving low-carbon expansion generation planning is critical for carbon emission mitigation and a lowcarbon economy.In this paper,a two-layer low-carbon expansion generation planning approach considering the uncertainty of renewable energy at multiple time scales is proposed.First,renewable energy sequences considering the uncertainty in multiple time scales are generated based on the Copula function and the probability distribution of renewable energy.Second,a two-layer generation planning model considering carbon trading and carbon capture technology is established.Specifically,the upper layer model optimizes the investment decision considering the uncertainty at a monthly scale,and the lower layer one optimizes the scheduling considering the peak shaving at an hourly scale and the flexibility at a 15-minute scale.Finally,the results of different influence factors on low-carbon generation expansion planning are compared in a provincial power grid,which demonstrate the effectiveness of the proposed model.
基金Supported by Shandong Natural Science Foundation ( ZR2011GQ009)Humanities and Social Science Planning Project of the Ministry of Education (12YJC880021)Project of the Ministry of Housing and Urban-Rural Development (2011-R3-12)
文摘Through literature research and expert interviews,we extract 10 variables influencing the new generation migrant workers' employability,and establish the comprehensive evaluation model of the new generation migrant workers' employability. Using factor analysis,we derive that the model includes three factors: skill literacy,relationship literacy and basic literacy. The weights of each factor are 0. 580,0. 244 and 0. 174 8,respectively. Skill literacy is affected by skill level,learning ability,career aspiration,ability to analyze problems,physical health status and other factors. Relationship literacy is affected by the sense of teamwork,interpersonal skills,social support and other factors. Basic literacy is affected by educational level,hardworking spirit and other factors. According to the results,we put forth the following recommendations to improve the new generation migrant workers' employability: strengthening the vocational skill training; coordinating the vocational education resources.
基金This work was supported by the National Key Research and Development Program of China(2022YFB4101600,2022YFB4101605)the National Natural Science Foundation of China(52372175,51972040)+1 种基金the Innovation and Technology Fund of Dalian(N2023JJ12GX020,2022JJ12GX023)Liaoning Normal University 2022 Outstanding Research Achievements Cultivation Fund(No.22GDL002).The authors also acknowledge the assistance of the DUT Instrumental Analysis Center.
文摘Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing electricity.However,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG simultaneously.Herein,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from TSG.It enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam generation.Meanwhile,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity generation.These benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high voltage.Directly interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity supply.It produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.
基金Supported by People's Livelihood Survey Project of 2011 Hebei Provincial Social Science Development Research(20111278)
文摘Based on survey data of current situations of new generation migrant workers vocational education and its influence on social mobility in Shijiazhuang City, the author believes that there are many drawbacks in vocational education of new generation migrant workers, including low participationt and varied training environment of enterprises. In addition, the influence of vocational education of migrant workers on social mobility is not very satisfactory. Finally, it presents countermeasures for improving vocational education, to promote social mobility of new generation migrant workers.