Injection-production coupling(IPC) technology holds substantial potential for boosting oil recovery and enhancing economic efficiency.Despite this potential,discussion on gas injection coupling,especially in relation ...Injection-production coupling(IPC) technology holds substantial potential for boosting oil recovery and enhancing economic efficiency.Despite this potential,discussion on gas injection coupling,especially in relation to microscopic mechanisms,remains relatively sparse.This study utilizes microscopic visualization experiments to investigate the mechanisms of residual oil mobilization under various IPC scenarios,complemented by mechanical analysis at different stages.The research quantitatively assesses the degree of microscopic oil recovery and the distribution of residual oil across different injection-production methods.Findings reveal that during the initial phase of continuous gas injection(CGI),the process closely mimics miscible displacement,gradually transitioning to immiscible displacement as CO_(2)extraction progresses.Compared to CGI,the asynchronous injection-production(AIP) method improved the microscopic oil recovery rate by 6.58%.This enhancement is mainly attributed to significant variations in the pressure field in the AIP method,which facilitate the mobilization of columnar and porous re sidual oil.Furthermo re,the synchronous cycle injection(SCI) method increased microscopic oil recovery by 13.77% and 7.19% compared to CGI and AIP,respectively.In the SCI method,membrane oil displays filame ntary and Karman vo rtex street flow patterns.The dissolved and expanded crude oil te nds to accumulate and grow at the oil-solid interface due to adhesive forces,thereby reducing migration resistance.The study findings provide a theoretical foundation for improving oil recovery in lowpermeability reservoirs.展开更多
The 14th Five-Year Plan period is a critical period for China to achieve high-quality development. Based on super-efficiency slacks-based measure(SBM) model, grey-related analysis(GRA) and other models, this paper stu...The 14th Five-Year Plan period is a critical period for China to achieve high-quality development. Based on super-efficiency slacks-based measure(SBM) model, grey-related analysis(GRA) and other models, this paper studies the heterogeneity of the coupling relationship among technological innovation, industrial transformation and environmental efficiency in the Huaihai Economic Zone during the period of 2005-2019. In addition, it analyzes the coupling mechanism of single and binary systems to the ternary system, which is of great significance for the collaborative symbiosis among systems. The findings are as follows. 1) The technological innovation, industrial transformation and environmental efficiency(TIE) systems of the Huaihai Economic Zone had significant spatial-temporal heterogeneity. Although their evaluation value fluctuated, the development trends are all positive. Ultimately, technological innovation is characterized by being high in the northeast and low in the southwest around Xuzhou, while other systems are relatively staggered in space. 2) The coupling of TIE systems is in transition, lack of orderly integration and benign interaction. However, the developing trend of interaction is also upward, and a spatial pattern driven by Xuzhou and Linyi as the dual cores has gradually formed. Moreover, the coupling is mostly manifested as outdated technological innovation and industrial transformation. Except for the final coordination of regenerative cities, the other resource types are all in transition. Cities in all traffic locations are still in transition. The overall system interaction of cities on Longhai Line(Lanzhou-Lianyungang Railway) is relatively optimal, and cities on Xinshi Line(Xinxiang-Rizhao Railway) are accelerating toward synergy. 3) The coupling status of TIE systems depends on the development of the single system and the interaction of the binary(2E) system. The coupling is closely related to technological innovation and Technology-Industry system,and is hindered by the inefficient interaction of Technology-Environment system. Specifically, the synergy of regenerative cities is attributed to the advantage of a single system and the effective integration of 2E systems. Beneficial from the advantages of environmental efficiency, the cities on Xinshi Line promote the synergy of the 2E and TIE systems. Therefore, while the Huaihai Economic Zone stimulates the development potential of the single and 2E systems, it is necessary to amplify the superimposition effect of systems in accordance on the basis of resource and location.展开更多
Hydraulic fracturing technology has played an important role in the exploitation of unconventional oil and gas resources,however,its application to gas hydrate reservoirs has been rarely studied.Currently,there is sti...Hydraulic fracturing technology has played an important role in the exploitation of unconventional oil and gas resources,however,its application to gas hydrate reservoirs has been rarely studied.Currently,there is still limited understanding of the propagation and extension of fractures around the wellbore during the fracturing process of horizontal wells in hydrate reservoirs,as well as the stress interference patterns between fractures.This study simulates hydraulic fracturing processes in hydrate reservoirs using a fluidsolid coupling discrete element method(DEM),and analyzes the impacts of hydrate saturation and geological and engineering factors on fracture extension and stress disturbance.The results show that hydraulic fracturing is more effective when hydrate saturation exceeds 30%and that fracture pressure increases with saturation.The increase in horizontal stress differential enhances the directionality of fracture propagation and reduces stress disturbance.The distribution uniformity index(DUI)reveals that injection pressure is directly proportional to the number of main fractures and inversely proportional to fracturing time,with fracturing efficiency depending on the spacing between injection points and the distance between wells.This work may provide reference for the commercial exploitation of natural gas hydrates.展开更多
This paper provides a comprehensive reflection on the evolution of globalization research in the Pearl River Delta(PRD),considering the current international context and national strategies.It identifies several chall...This paper provides a comprehensive reflection on the evolution of globalization research in the Pearl River Delta(PRD),considering the current international context and national strategies.It identifies several challenges in existing studies,such as the ambiguity of globalization patterns and the insufficient representativeness of key indicators.In response to these challenges,this paper draws upon the theory of strategic coupling to propose a new theoretical framework for analyzing globalization in latecomer regions.Based on the concepts of spatial stickiness and locational advantages,this paper further develops a two-dimensional quantitative indicator matrix.Using the PRD as a case study,it conducts empirical measurements and analysis,leading to three main conclusions.First,the theory of strategic coupling proves well-suited for analyzing the globalization of latecomer regions,exemplified by the PRD.It offers a more systematic,clearer,and more robust explanatory framework compared to traditional measurement methods.Second,the empirical analysis from the PRD reveals that the pattern of regional globalization does not follow a simple linear growth or cyclical model.Instead,it exhibits a circuitous,complex,and upward spiral,unfolding along an S-shaped evolutionary trajectory.Third,through comparisons of the eastern and western shores,as well as segmented city analyses,this study finds that locational advantages significantly shape the evolutionary pattern of globalization.This influence is not only apparent during the region's initial take-off phase but also plays a more profound role in shaping its subsequent developmental trajectory.This study makes a distinctive contribution to both the theoretical understanding of globalization in latecomer regions and the practical field of regional economic development in China.Additionally,it introduces a novel measurement approach for studying regional globalization.展开更多
The marine biopharmaceutical industry(MBI)has been considered as an important part of the blue economy.The high-quality development of this industry depends on the high-level coordinated development of technological i...The marine biopharmaceutical industry(MBI)has been considered as an important part of the blue economy.The high-quality development of this industry depends on the high-level coordinated development of technological innovation system(TIS).In the present study,the coupling mechanism of industrial innovation input subsystem and innovation output subsystem was analyzed for the first time.On this basis,the development level and coupling coordination level of TIS in China’s MBI during 2008-2018 were empirically evaluated with the capacity coupling coordination model.Then,the obstacle factors were diagnosed and recognized with the obstacle model.The results showed that the innovation input index fluctuated at a low level in China’s MBI.The innovation output index has basically maintained a growth trend,whereas the quality of development was not high.Although the coupling coordination level of TIS showed a positive change as mild disordered→primary coordinated→well-coordinated,the development type of innovation system has changed from the lagging output of innovation into the lagging input of innovation.Insufficient input of innovation factors remained the main obstacle to the improvement of coordination level.Based on the above analysis,suggestions were put forward from the perspectives of policy and fund guarantees to improve the coupling coordination level in China’s MBI.展开更多
As an important part of buoy-type ocean monitoring systems,the inductively coupled mooring chain solves the problem of data cotransmission through the multinode sensors that it carries,which is significant for the rap...As an important part of buoy-type ocean monitoring systems,the inductively coupled mooring chain solves the problem of data cotransmission through the multinode sensors that it carries,which is significant for the rapid acquisition of fish,hydrology,and other information.This paper is based on a seawater channel transmission model with a depth of 300 m and a bandwidth of 2 MHz.An orthogonal frequency division multiplexing(OFDM)technology is used to overcome the multipath effect of signal transmission on a seawater medium.The adaptive technology is integrated into the OFDM,and an improved joint subcarrier and bit power allocation algorithm is proposed.This algorithm solves the problem of dynamic subcarrier allocation during the cotransmission of underwater multinode user data in seawater channels.The results show that the algorithm complexity can be reduced by 0.18126×10^(-2)s during one complete OFDM system data transmission by the improved greedy algorithm,and a total of 216 bits are transmitted by the OFDM.The normalized channel capacity can be improved by 0.012 bit s^(-1)Hz^(-1).At the bit error ratio(BER)of 10^(-3),the BER performance can be improved by approximately 6 d B.When the numbers of users are 4 and 8,the improved algorithm increases the channel capacity,and the higher the number of users,the more evident the channel capacity improvement effect is.The results of this paper have an important reference value for enhancing the transmission performance of inductively coupled mooring chain underwater multinode data.展开更多
Objective: To explore the potential predictors of a live birth (LB) outcome among subfertile couples of Asian ethnicity undergoing the first fertility treatment cycle;to assess the cumulative live birth rates after su...Objective: To explore the potential predictors of a live birth (LB) outcome among subfertile couples of Asian ethnicity undergoing the first fertility treatment cycle;to assess the cumulative live birth rates after successive cycles;and to determine the incidence rate of spontaneous conception (SC).Methods:Subfertile couples were grouped according to treatment modalities at the first fertility treatment cycle: intrauterine insemination (IUI),in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and no treatment, and were followed-up for duration up to seven years. Multivariable logistic regression analysis was used for statistical analyses. Results: Age of female subjects [35-38 years, odds ratio (OR): 0.39;≥39 years, OR: 0.14], uterine factor subfertility (OR: 5.24), and treatment modalities (ORs: IUI 0.25, IVF 2.33 and ICSI 1.91) significantly predicted a LB outcome (P<0.05). The cumulative live birth rates were 11.7% IUI, 41.5% IVF, 27.5% ICSI and 22.6% from frozen embryo transfer cycles. The cumulative SC rate was 24.6% in the non-treated group and 10.7% in the treated group. All LBs from IVF cycles were delivered by the second cycle and within four years, compared to SC delivery of within five years in the non-treated group and six years in the treated group. Conclusions:Age of female subject, uterine factor and modalities of treatment are significant predictors for LB outcome at the first cycle. Higher delivery rates could be achieved following fewer successive IVF cycles and within a shorter duration compared to SC.展开更多
Migration and innovation is the driving force of scientific and technological development.By analyzing the coupling relationship between the two,this paper finds out the common elements shared by the two factors,and c...Migration and innovation is the driving force of scientific and technological development.By analyzing the coupling relationship between the two,this paper finds out the common elements shared by the two factors,and constructs the coupling guarantee mechanism between them,so as to provide suggestions for the coordination,win-win and synchronous benign development of the spirit of makers and the development of scientific and technological innovation,and promote the sustainable development of the national innovation system.展开更多
The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic pe...The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic perspective,the seriousness of rural water quality,soil and atmospheric pollution in Xiangxiang,Xiangtan and the surrounding areas in Shaoshan irrigated area was revealed.The control measure which was 'four-dimensional pollution in the city and countryside'—— low-carbon-high-value agriculture and the technology innovation was proposed.The low-carbon-high-value technology innovation industrialization demonstration in three parts which included the pre-production,mid-production and post-production deep-processing of cultivation and breeding industry in the ecological cyclic agricultural garden in Shaoshan irrigated area was the driving force.We tried to propel the low-carbon ecological cultivation and breeding industry which included the paddy rice,grass,tree,medicinal herbs and pig,cow,chick,duck,fish.We wanted to relieve the structural unbalance of previous cultivation and breeding industry,'cheap grain hurting the farmers' and the short-leg problem of social-economic-ecological benefit.The results showed that the low-carbon-high-value agricultural system was a poly-generation technology system which promoted the multi-level and grading utilization,saved the energy,reduced the consumption and cleaned the production based on the ecology.展开更多
Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic h...Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.展开更多
The determining factor of<em> Setaria italica </em>(L.) P. Beauv. is the coupling of its flowering stage and outcrossing rate which leads to low and unstable seed yields in self-pollinated foxtail millet h...The determining factor of<em> Setaria italica </em>(L.) P. Beauv. is the coupling of its flowering stage and outcrossing rate which leads to low and unstable seed yields in self-pollinated foxtail millet hybrids and thereby limits their large-scale application. In this study, Datong 27, Datong 29 and gu 83 were screened and identified through meticulous observations of their pollination habitats. High exposure rate, degree of exposure and plump of stigma are good factors to accept foreign pollen. Datong 27 and Datong 29 have some additional characteristics, such as long filaments and exposed and full anthers that contain a large amount of pollen. We transformed into a series of stigma-exposed and plump sterile lines that easily accepted exotic pollen. New restorer lines with anthers that were full of powder and exhibited quick recovery, which improved the parental lines’ heterosexual characteristics. By tracking and monitoring the leaf development of the new sterile and restorer lines, a coupling law of leaf development was determined and a series of flowering control measures were formulated. These factors ensured that the parental lines encounter one another during the flowering stage. By utilizing fertilizer and water, the vitality of the female stigma, amount of powder scattered and powder loosening time were prolonged, which increased hybrid seed yields from 1500 to 3000 kg/hm<sup>2</sup>. These findings were helpful in resolving the technical problems of seed production that restricted the propagation of foxtail millet hybrids and supporting future large-scale applications.展开更多
How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model mus...How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model must first be constructed and then solved by programming.Obviously, this method is not very practical. This paper,therefore, proposes a new way of approach with a new method using 3- D animation for the solving of coupling relations in the 6 - DOF parallel robot. This method is much simpler and its solving accuracy approaches that of the more complicated analytic method.展开更多
We have investigated in this study the destruction of acetone and toluene with AL-KO PURE air purifier (AL-KO PURE) on industrial scale. In the case of acetone, 100% pollutant abatement is achieved with AL-KO PURE ove...We have investigated in this study the destruction of acetone and toluene with AL-KO PURE air purifier (AL-KO PURE) on industrial scale. In the case of acetone, 100% pollutant abatement is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.5 ppm (1187 μg/m3, about 7 times higher than the average living room level). This corresponds to 0.2 μmol/s with a flow rate of 38.42 m3/h. The regeneration of a saturated catalytic filter was also tested. When the catalytic filter of AL-KO PURE is fully saturated with acetone, a 100% acetone destruction efficiency can be achieved at 0.46 ppm concentration with 25% fan speed. Moreover the second pollutant, toluene, has been also studied. 100% toluene abatement also is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.2 ppm (811 μg/m3, 0.087 μmol/s with a flow rate of 38.42 m3/h). Finally, the availability for the simultaneous removal of both pollutants, acetone and toluene, has been also studied.展开更多
基金supported by the National Natural Science Foundation of China (Nos.52374064,51974347,52474072)the Shandong Provincial Universities Youth Innovation and Technology Support Program (2022KJ065)。
文摘Injection-production coupling(IPC) technology holds substantial potential for boosting oil recovery and enhancing economic efficiency.Despite this potential,discussion on gas injection coupling,especially in relation to microscopic mechanisms,remains relatively sparse.This study utilizes microscopic visualization experiments to investigate the mechanisms of residual oil mobilization under various IPC scenarios,complemented by mechanical analysis at different stages.The research quantitatively assesses the degree of microscopic oil recovery and the distribution of residual oil across different injection-production methods.Findings reveal that during the initial phase of continuous gas injection(CGI),the process closely mimics miscible displacement,gradually transitioning to immiscible displacement as CO_(2)extraction progresses.Compared to CGI,the asynchronous injection-production(AIP) method improved the microscopic oil recovery rate by 6.58%.This enhancement is mainly attributed to significant variations in the pressure field in the AIP method,which facilitate the mobilization of columnar and porous re sidual oil.Furthermo re,the synchronous cycle injection(SCI) method increased microscopic oil recovery by 13.77% and 7.19% compared to CGI and AIP,respectively.In the SCI method,membrane oil displays filame ntary and Karman vo rtex street flow patterns.The dissolved and expanded crude oil te nds to accumulate and grow at the oil-solid interface due to adhesive forces,thereby reducing migration resistance.The study findings provide a theoretical foundation for improving oil recovery in lowpermeability reservoirs.
基金Under the auspices of National Natural Science Foundation of China(No.41971158)National Social Science Foundation of China(No.20BJL106)+1 种基金Cultural Experts and Four batches Talents Independently Selected Topic Project(No.ZXGZ[2018]86)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_0357)。
文摘The 14th Five-Year Plan period is a critical period for China to achieve high-quality development. Based on super-efficiency slacks-based measure(SBM) model, grey-related analysis(GRA) and other models, this paper studies the heterogeneity of the coupling relationship among technological innovation, industrial transformation and environmental efficiency in the Huaihai Economic Zone during the period of 2005-2019. In addition, it analyzes the coupling mechanism of single and binary systems to the ternary system, which is of great significance for the collaborative symbiosis among systems. The findings are as follows. 1) The technological innovation, industrial transformation and environmental efficiency(TIE) systems of the Huaihai Economic Zone had significant spatial-temporal heterogeneity. Although their evaluation value fluctuated, the development trends are all positive. Ultimately, technological innovation is characterized by being high in the northeast and low in the southwest around Xuzhou, while other systems are relatively staggered in space. 2) The coupling of TIE systems is in transition, lack of orderly integration and benign interaction. However, the developing trend of interaction is also upward, and a spatial pattern driven by Xuzhou and Linyi as the dual cores has gradually formed. Moreover, the coupling is mostly manifested as outdated technological innovation and industrial transformation. Except for the final coordination of regenerative cities, the other resource types are all in transition. Cities in all traffic locations are still in transition. The overall system interaction of cities on Longhai Line(Lanzhou-Lianyungang Railway) is relatively optimal, and cities on Xinshi Line(Xinxiang-Rizhao Railway) are accelerating toward synergy. 3) The coupling status of TIE systems depends on the development of the single system and the interaction of the binary(2E) system. The coupling is closely related to technological innovation and Technology-Industry system,and is hindered by the inefficient interaction of Technology-Environment system. Specifically, the synergy of regenerative cities is attributed to the advantage of a single system and the effective integration of 2E systems. Beneficial from the advantages of environmental efficiency, the cities on Xinshi Line promote the synergy of the 2E and TIE systems. Therefore, while the Huaihai Economic Zone stimulates the development potential of the single and 2E systems, it is necessary to amplify the superimposition effect of systems in accordance on the basis of resource and location.
基金financially supported by the National Key Research and Development Plan(2023YFC2811001)the National Natural Science Foundation of China(42206233)the Taishan Scholars Program(tsqn202312280,tsqn202306297)。
文摘Hydraulic fracturing technology has played an important role in the exploitation of unconventional oil and gas resources,however,its application to gas hydrate reservoirs has been rarely studied.Currently,there is still limited understanding of the propagation and extension of fractures around the wellbore during the fracturing process of horizontal wells in hydrate reservoirs,as well as the stress interference patterns between fractures.This study simulates hydraulic fracturing processes in hydrate reservoirs using a fluidsolid coupling discrete element method(DEM),and analyzes the impacts of hydrate saturation and geological and engineering factors on fracture extension and stress disturbance.The results show that hydraulic fracturing is more effective when hydrate saturation exceeds 30%and that fracture pressure increases with saturation.The increase in horizontal stress differential enhances the directionality of fracture propagation and reduces stress disturbance.The distribution uniformity index(DUI)reveals that injection pressure is directly proportional to the number of main fractures and inversely proportional to fracturing time,with fracturing efficiency depending on the spacing between injection points and the distance between wells.This work may provide reference for the commercial exploitation of natural gas hydrates.
基金National Natural Science Foundation of China,No.42271182,No.42122006,No.42101171。
文摘This paper provides a comprehensive reflection on the evolution of globalization research in the Pearl River Delta(PRD),considering the current international context and national strategies.It identifies several challenges in existing studies,such as the ambiguity of globalization patterns and the insufficient representativeness of key indicators.In response to these challenges,this paper draws upon the theory of strategic coupling to propose a new theoretical framework for analyzing globalization in latecomer regions.Based on the concepts of spatial stickiness and locational advantages,this paper further develops a two-dimensional quantitative indicator matrix.Using the PRD as a case study,it conducts empirical measurements and analysis,leading to three main conclusions.First,the theory of strategic coupling proves well-suited for analyzing the globalization of latecomer regions,exemplified by the PRD.It offers a more systematic,clearer,and more robust explanatory framework compared to traditional measurement methods.Second,the empirical analysis from the PRD reveals that the pattern of regional globalization does not follow a simple linear growth or cyclical model.Instead,it exhibits a circuitous,complex,and upward spiral,unfolding along an S-shaped evolutionary trajectory.Third,through comparisons of the eastern and western shores,as well as segmented city analyses,this study finds that locational advantages significantly shape the evolutionary pattern of globalization.This influence is not only apparent during the region's initial take-off phase but also plays a more profound role in shaping its subsequent developmental trajectory.This study makes a distinctive contribution to both the theoretical understanding of globalization in latecomer regions and the practical field of regional economic development in China.Additionally,it introduces a novel measurement approach for studying regional globalization.
基金supported by the National Natural Science Foundation of China(Nos.42176126,42076221)the Department of Marine Strategic Planning and Economy,Ministry of Natural Resources of China,and Marine Development Research Society of China(No.CAMA201817).
文摘The marine biopharmaceutical industry(MBI)has been considered as an important part of the blue economy.The high-quality development of this industry depends on the high-level coordinated development of technological innovation system(TIS).In the present study,the coupling mechanism of industrial innovation input subsystem and innovation output subsystem was analyzed for the first time.On this basis,the development level and coupling coordination level of TIS in China’s MBI during 2008-2018 were empirically evaluated with the capacity coupling coordination model.Then,the obstacle factors were diagnosed and recognized with the obstacle model.The results showed that the innovation input index fluctuated at a low level in China’s MBI.The innovation output index has basically maintained a growth trend,whereas the quality of development was not high.Although the coupling coordination level of TIS showed a positive change as mild disordered→primary coordinated→well-coordinated,the development type of innovation system has changed from the lagging output of innovation into the lagging input of innovation.Insufficient input of innovation factors remained the main obstacle to the improvement of coordination level.Based on the above analysis,suggestions were put forward from the perspectives of policy and fund guarantees to improve the coupling coordination level in China’s MBI.
基金the National Natural Science Foundation of China(No.62071329)the National Science Foundation of Tianjin(No.20JCYB JC00130)。
文摘As an important part of buoy-type ocean monitoring systems,the inductively coupled mooring chain solves the problem of data cotransmission through the multinode sensors that it carries,which is significant for the rapid acquisition of fish,hydrology,and other information.This paper is based on a seawater channel transmission model with a depth of 300 m and a bandwidth of 2 MHz.An orthogonal frequency division multiplexing(OFDM)technology is used to overcome the multipath effect of signal transmission on a seawater medium.The adaptive technology is integrated into the OFDM,and an improved joint subcarrier and bit power allocation algorithm is proposed.This algorithm solves the problem of dynamic subcarrier allocation during the cotransmission of underwater multinode user data in seawater channels.The results show that the algorithm complexity can be reduced by 0.18126×10^(-2)s during one complete OFDM system data transmission by the improved greedy algorithm,and a total of 216 bits are transmitted by the OFDM.The normalized channel capacity can be improved by 0.012 bit s^(-1)Hz^(-1).At the bit error ratio(BER)of 10^(-3),the BER performance can be improved by approximately 6 d B.When the numbers of users are 4 and 8,the improved algorithm increases the channel capacity,and the higher the number of users,the more evident the channel capacity improvement effect is.The results of this paper have an important reference value for enhancing the transmission performance of inductively coupled mooring chain underwater multinode data.
文摘Objective: To explore the potential predictors of a live birth (LB) outcome among subfertile couples of Asian ethnicity undergoing the first fertility treatment cycle;to assess the cumulative live birth rates after successive cycles;and to determine the incidence rate of spontaneous conception (SC).Methods:Subfertile couples were grouped according to treatment modalities at the first fertility treatment cycle: intrauterine insemination (IUI),in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and no treatment, and were followed-up for duration up to seven years. Multivariable logistic regression analysis was used for statistical analyses. Results: Age of female subjects [35-38 years, odds ratio (OR): 0.39;≥39 years, OR: 0.14], uterine factor subfertility (OR: 5.24), and treatment modalities (ORs: IUI 0.25, IVF 2.33 and ICSI 1.91) significantly predicted a LB outcome (P<0.05). The cumulative live birth rates were 11.7% IUI, 41.5% IVF, 27.5% ICSI and 22.6% from frozen embryo transfer cycles. The cumulative SC rate was 24.6% in the non-treated group and 10.7% in the treated group. All LBs from IVF cycles were delivered by the second cycle and within four years, compared to SC delivery of within five years in the non-treated group and six years in the treated group. Conclusions:Age of female subject, uterine factor and modalities of treatment are significant predictors for LB outcome at the first cycle. Higher delivery rates could be achieved following fewer successive IVF cycles and within a shorter duration compared to SC.
基金This paper is one of the achievements of the general projects of the National Social Science Foundation project in 2017,the project name is"Study on the Cooperative Development Mechanism Between Librarians and Creators in the Library Maker Space Service System"(item number:17BTQ033)。
文摘Migration and innovation is the driving force of scientific and technological development.By analyzing the coupling relationship between the two,this paper finds out the common elements shared by the two factors,and constructs the coupling guarantee mechanism between them,so as to provide suggestions for the coordination,win-win and synchronous benign development of the spirit of makers and the development of scientific and technological innovation,and promote the sustainable development of the national innovation system.
基金Supported by " Research on The Control Technology of Subtropical Agriculture Pollution System" Special Project of National Environment Protection Public Welfare Industry Science Research "Research on The Construction Strategy of Ecological Civilization" Development Plan Research Project of State Development and Reform Commission+1 种基金Xiangxiang " High-output and Efficient Cultivation of High Quality Rice and Processing Technology Industrialization Demonstration " in The Plan Test Site of National Science and Technology Enriching People and Developing County Special Project Action" Xiangxiang Middle and Long-term Development Plan of Modern Agriculture" of Subtropical Agriculture Ecology Institute in Chinese Academy of Science
文摘The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic perspective,the seriousness of rural water quality,soil and atmospheric pollution in Xiangxiang,Xiangtan and the surrounding areas in Shaoshan irrigated area was revealed.The control measure which was 'four-dimensional pollution in the city and countryside'—— low-carbon-high-value agriculture and the technology innovation was proposed.The low-carbon-high-value technology innovation industrialization demonstration in three parts which included the pre-production,mid-production and post-production deep-processing of cultivation and breeding industry in the ecological cyclic agricultural garden in Shaoshan irrigated area was the driving force.We tried to propel the low-carbon ecological cultivation and breeding industry which included the paddy rice,grass,tree,medicinal herbs and pig,cow,chick,duck,fish.We wanted to relieve the structural unbalance of previous cultivation and breeding industry,'cheap grain hurting the farmers' and the short-leg problem of social-economic-ecological benefit.The results showed that the low-carbon-high-value agricultural system was a poly-generation technology system which promoted the multi-level and grading utilization,saved the energy,reduced the consumption and cleaned the production based on the ecology.
基金the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003).
文摘Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.
文摘The determining factor of<em> Setaria italica </em>(L.) P. Beauv. is the coupling of its flowering stage and outcrossing rate which leads to low and unstable seed yields in self-pollinated foxtail millet hybrids and thereby limits their large-scale application. In this study, Datong 27, Datong 29 and gu 83 were screened and identified through meticulous observations of their pollination habitats. High exposure rate, degree of exposure and plump of stigma are good factors to accept foreign pollen. Datong 27 and Datong 29 have some additional characteristics, such as long filaments and exposed and full anthers that contain a large amount of pollen. We transformed into a series of stigma-exposed and plump sterile lines that easily accepted exotic pollen. New restorer lines with anthers that were full of powder and exhibited quick recovery, which improved the parental lines’ heterosexual characteristics. By tracking and monitoring the leaf development of the new sterile and restorer lines, a coupling law of leaf development was determined and a series of flowering control measures were formulated. These factors ensured that the parental lines encounter one another during the flowering stage. By utilizing fertilizer and water, the vitality of the female stigma, amount of powder scattered and powder loosening time were prolonged, which increased hybrid seed yields from 1500 to 3000 kg/hm<sup>2</sup>. These findings were helpful in resolving the technical problems of seed production that restricted the propagation of foxtail millet hybrids and supporting future large-scale applications.
文摘How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model must first be constructed and then solved by programming.Obviously, this method is not very practical. This paper,therefore, proposes a new way of approach with a new method using 3- D animation for the solving of coupling relations in the 6 - DOF parallel robot. This method is much simpler and its solving accuracy approaches that of the more complicated analytic method.
文摘We have investigated in this study the destruction of acetone and toluene with AL-KO PURE air purifier (AL-KO PURE) on industrial scale. In the case of acetone, 100% pollutant abatement is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.5 ppm (1187 μg/m3, about 7 times higher than the average living room level). This corresponds to 0.2 μmol/s with a flow rate of 38.42 m3/h. The regeneration of a saturated catalytic filter was also tested. When the catalytic filter of AL-KO PURE is fully saturated with acetone, a 100% acetone destruction efficiency can be achieved at 0.46 ppm concentration with 25% fan speed. Moreover the second pollutant, toluene, has been also studied. 100% toluene abatement also is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.2 ppm (811 μg/m3, 0.087 μmol/s with a flow rate of 38.42 m3/h). Finally, the availability for the simultaneous removal of both pollutants, acetone and toluene, has been also studied.
