Studying tiie urban landscape pattern plays a crucial role in scientific land use and management and in improving the urban ecological environment In this paper, AutoCAD, ArcGIS, Fragstats, and other software were u...Studying tiie urban landscape pattern plays a crucial role in scientific land use and management and in improving the urban ecological environment In this paper, AutoCAD, ArcGIS, Fragstats, and other software were used to analyse the data of the fourth phase of land use in the core atea of Yangling Demonstration Zone. The results showed that： ① in the core area, the percentage of construction land incteased from 18.22% to 61.72%, and the percentage of agricultufal land decreased from 58.36% to 11.14%. And the fafm land was fragmented, and traffic connectivily was strengthened. The afea of garden land was reduced from 251.89 hm2 to 50.38 hm^2, and the landscape metric of forest land showed an inverted V-shaped curve. ②The year 2009 in four phases witnessed the greatest landscape fragmentation, both Edge Density （ED） and Ingest Patch Index （LPI） increased, and human interference enhanced the overall landscape complexity. Measures were fotmulated in terms of deaf development goals, optimized allocation of land resoutces, effective protection of ecological ted lines, and definite ecological responsibility, so as to optimize the urban landscape pattern.展开更多
In comparison to the construction of modern highway engineering,several of China’s early pavement construction concerns,such as pavement collapse,are rather clear.Limited by historical and technical factors,the subgr...In comparison to the construction of modern highway engineering,several of China’s early pavement construction concerns,such as pavement collapse,are rather clear.Limited by historical and technical factors,the subgrade and pavement design for highways lacks scientificity,thus inducing potential safety problems in the operation.In order to comprehensively improve the subgrade and pavement design as well as ensure the quality and safety of highway engineering projects,this paper takes the reconstructed and expanded highway projects as research subjects and focuses on proposing optimization measures for the subgrade and pavement design of reconstructed and expanded highways,so as to provide adequate reference.展开更多
Objective:To explore the clinical effect of perioperative nursing guided by the concept of enhanced recovery after surgery and summarize them.Methods:Pubmed,Chinese National Knowledge Infrastructure(CNKI),Chinese Biom...Objective:To explore the clinical effect of perioperative nursing guided by the concept of enhanced recovery after surgery and summarize them.Methods:Pubmed,Chinese National Knowledge Infrastructure(CNKI),Chinese Biomedical Literature Database(CBM),Wanfang Database,and VIP Database were searched to obtain the relevant literature involving enhanced recovery after surgery(ERAS)guidance,obtain the effective clinical data,review the reports in literature,and obtain the effective scheme.Results:Compared with the traditional nursing program,perioperative nursing principles guided by the concept of ERAS provide more accurate nursing care to patients and reduce the occurrence of intraoperative stress events through comprehensive nursing measures such as preoperative pre-rehabilitation measures,intraoperative body temperature and fluid management,postoperative analgesia,prevention of nausea and vomiting,early mobilization,catheter nursing,and better out-of-hospital follow-up.Conclusions:Perioperative nursing principles guided by the concept of ERAS can significantly reduce the incidence of perioperative complications,shorten the hospital stay of patients,and promote postoperative rehabilitation of patients.The transformation and implementation of this concept can bring significant benefits to hospitals,medical care,and patients.展开更多
In Colleges and universities,the organization of Ideological and political teaching courses can strengthen the ideological education of students,but at present there are still some problems in the ideological and poli...In Colleges and universities,the organization of Ideological and political teaching courses can strengthen the ideological education of students,but at present there are still some problems in the ideological and political teaching in Colleges and universities,the ideological and political teaching has not achieved the expected effect,and the ideological and political teaching will be hindered in the work.This paper focuses on the connotation of Ideological and political teaching in Colleges and universities,and puts forward the measures of transformation and upgrading of Ideological and political teaching management.展开更多
In order to study the diurnal variation of soil CO2 effiux from temperate meadow steppes in Northeast China, and determine the best time for observation, a field experiment was conducted with a LI-6400 soil CO2 flux s...In order to study the diurnal variation of soil CO2 effiux from temperate meadow steppes in Northeast China, and determine the best time for observation, a field experiment was conducted with a LI-6400 soil CO2 flux system under five typical plant communi- ties （Suaeda glauca （Sg）, Chloris virgata （Cv）, Puecinellia distans （Pd）, Leymus chinensis （Lc） and Phragmites australis （Pa）） and an alkali-spot land （As） at the meadow steppe of western Songnen Plain. The results showed that the diurnal variation of soil CO2 effiux exhibited a single peak curve in the growing season. Diurnal maximum soil respiration （Rs） often appeared between 1 1：00 and 13：00, while the minimum occurred at 21：00-23：00 or before dawn. Air temperature near the soil surface （Ta） and soil temperature at 10 cm depth （Tlo） exerted dominant control on the diurnal variations of soil respiration. The time-windows 7：00-9：00 could be used as the optimal measuring time to represent the daily mean soil CO2 effiux at the Cv, Pd, Lc and Pa sites. The daily mean soil CO2 effiux was close to the soil COz effiux from 15：00 to 17：00 and the mean of 2 individual soil CO2 effiux from 15：00 to 19：00 at the As and Sg sites, respectively. During nocturnal hours, negative soil CO2 fluxes （CO2 downwards into the soil） were frequently observed at the As and Sg sites, the magnitude of the negative CO2 fluxes were 0.10-1.55 gmol/（m2.s） and 0.10-0.69 gmol/（m2.s）at the two sites. The results im- plied that alkaline soils could absorb CO2 under natural condition, which might have significant implications to the global carbon budget accounting.展开更多
We firstly present a novel scheme for deterministic joint remote state preparation of an arbitrary five-qubit Brown state using four Greenberg-Horme-Zeilinger （GHZ） entangled states as the quantum channel. The succe...We firstly present a novel scheme for deterministic joint remote state preparation of an arbitrary five-qubit Brown state using four Greenberg-Horme-Zeilinger （GHZ） entangled states as the quantum channel. The success probability of this scheme is up to 1, which is superior to the existing ones. Moreover, the scheme is extended to the generalized case where three-qubit and four-qubit non-maximally entangled states are taken as the quantum channel. We simultaneously employ two common methods to reconstruct the desired state. By comparing these two methods, we draw a conclusion that the first is superior to the second-optimal positive operator-valued measure only taking into account the number of auxiliary particles and the success probability.展开更多
With the continuous development of modem science and technology,great changes have taken place in the advertising media industry where the traditional form of advertising has gradually changed into digital ones.Compar...With the continuous development of modem science and technology,great changes have taken place in the advertising media industry where the traditional form of advertising has gradually changed into digital ones.Compared with the traditional advertising,digital advertising has more flexibility and has a variety of forms in its advertising creation according to product itself.In addition,visual communication design plays a critical role where it is an important way to improve digital advertising.Therefore,it is necessary to optimize visual communication design in order to improve the quality of digital advertising.In this way,this article carries out an in-depth research and analysis on the visual communication design of digital media in digital advertising and put forward some reasonable suggestions and measures,aiming to further promote the development of China's advertising media industry.展开更多
In this paper, we study optimal recovery （reconstruction） of functions on the sphere in the average case setting. We obtain the asymptotic orders of average sampling numbers of a Sobolev space on the sphere with a G...In this paper, we study optimal recovery （reconstruction） of functions on the sphere in the average case setting. We obtain the asymptotic orders of average sampling numbers of a Sobolev space on the sphere with a Gaussian measure in the Lq （S^d-1） metric for 1 ≤ q ≤ ∞, and show that some worst-case asymptotically optimal algorithms are also asymptotically optimal in the average case setting in the Lq （S^d-1） metric for 1 ≤ q ≤ ∞.展开更多
The application of questioning as a teaching tool has always been considered as a main part of the teaching process.Based on the viewpoint of several researchers,a survey was conducted on the application of different ...The application of questioning as a teaching tool has always been considered as a main part of the teaching process.Based on the viewpoint of several researchers,a survey was conducted on the application of different questioning strategies by Chinese and foreign EFL teachers in a middle school,in order to determine their effects on students’language learning output and propose measures to optimize Chinese teachers’questioning strategies for improving students’learning efficiency.This research provides preliminary results based on the data collected from the video recordings of class sessions,a questionnaire,and an interview.According to the analysis,the questioning strategies differ between Chinese and foreign EFL teachers in many aspects,such as in information seeking,offering,modification,adjustment,feedback,and so forth.展开更多
To improve the efficiency and accuracy of kinematic calibration,the selection of measurement configurations is an important issue.In previous research,optimal measurement configurations mainly are selected by maximizi...To improve the efficiency and accuracy of kinematic calibration,the selection of measurement configurations is an important issue.In previous research,optimal measurement configurations mainly are selected by maximizing observability indices.However,the traditional observability indices only focus on the identification efficiency of the error parameters,while the purpose of robot kinematic calibration is to improve accuracy.To solve the inconsistency of the purpose between the observability index and calibration,the concept of the residual index to represent the residual distribution of the end effector after robot kinematic calibration with the measurement noise is proposed.Based on the quadratic form minimization of residuals,this article defines a specific residual index,O^(r),which is dimensionless and strictly better with the increase of measurement configurations.The indices are used to select measurement configurations in the kinematic calibration of a 5-DOF 2UPU/SP-RR hybrid robot,and the calibration results show that the proposed residual index is better than the traditional indices in the accuracy and stability of the end effector residual.展开更多
The nonductile reinforced concrete building(NDRCB)stock-typically,pre-1974 structures in the U.S.-is a well-known high-risk group for seismic hazards.Prior studies indicate that there are approximately 1500 NDRCBs in ...The nonductile reinforced concrete building(NDRCB)stock-typically,pre-1974 structures in the U.S.-is a well-known high-risk group for seismic hazards.Prior studies indicate that there are approximately 1500 NDRCBs in Los Angeles.Through various ordinances,the owners are currently required to choose between demolition and,when appropriate,seismic retrofitting.Because fulfilling these ordinances will take decades,the potential risk of major losses will persist.In this study,a method for automated development of structural analysis models and damage fragilities for non-ductile moment-resisting frames is established.This capability enables seismic risk assessment at a regional scale using relatively limited building metadata and the era-specific seismic design code.The approach is used first to develop archetypal models in OpenSees,verified through static pushover and nonlinear time-history analyses against prior detailed studies.Fragility curves for discrete damage states are developed through a probabilistic seismic demand model.Additional investigations are carried out to consider the influence of soil-structural interaction effects and to determine the most suitable seismic intensity measures to quantify the seismic damage levels of NDRCB frames.The sensitivity of the proposed modeling method to variations/uncertainties in building configurations and properties is also examined through parametric studies.The method is limited to a particular subcategory of NDRBCs-namely,moment-resisting frames-but extensions to other types appear straightforward.展开更多
The Songhua River Basin is a burgeoning agricultural area in the modern times in China. Particularly in recent years, increasing chemical fertilizers and pesticides have been applied with the development of agricultur...The Songhua River Basin is a burgeoning agricultural area in the modern times in China. Particularly in recent years, increasing chemical fertilizers and pesticides have been applied with the development of agricultural production. However, the situation of non- point source pollution （NSP） from agricultural production in this basin is still obscure. In order to solve the problem, the occurrence and distribution of acetochlor in sediments and riparian soils of the Songhua River Basin before rain season and after rain season were investigated. In addition, total organic carbon was analyzed. The result showed that the concentration of acetochlor ranged from 0.47 to 11.76 μg/kg in sediments and 0.03 to 709.37 μg/kg in riparian soils. During the high flow period in 2009, the mean concentration was 4.79 μg/kg in sediments and 0.75 μg]kg in riparian soils, respectively. Similarly, the mean concentration was 2.53 μg/kg in sediments and 61.36μg/kg in riparian soils, during the average flow period in 2010. There was a significant correlation between the concentration of acetochlor and total organic carbon in surface sediments. Moreover, the distribution of acetochlor in sediments of the Songhua River was significantly correlated to land use and topography of the watershed. The investigated data suggested that the concentration of acetochlor in the Songnen Plain and the Sanjiang Plain was higher than that in the other areas of the basin, and riparian buffering zones in these areas bad been destroyed by human activities. The optimal agricultural measures to alleviate the contamination of pesticides should be adopted, including controlling agricultural application of acetochlor and ecological restoration of riparian buffering strips.展开更多
In this paper we design the following two-step scheme to estimate the model parameter ω0 of the quantum system: first we utilize the Fisher information with respect to an intermediate variable v = cos(ω0 t) to deter...In this paper we design the following two-step scheme to estimate the model parameter ω0 of the quantum system: first we utilize the Fisher information with respect to an intermediate variable v = cos(ω0 t) to determine an optimal initial state and to seek optimal parameters of the POVM measurement operators; second we explore how to estimate ω0 from v by choosing t when a priori information knowledge of ω0 is available. Our optimal initial state can achieve the maximum quantum Fisher information. The formulation of the optimal time t is obtained and the complete algorithm for parameter estimation is presented. We further explore how the lower bound of the estimation deviation depends on the a priori information of the model.展开更多
One of the main obstacles for quantum-enhanced metrology is that the estimation accuracy enhanced by non-classical states is likely to be obliterated by noises. Here, we consider a scenario of phase estimation sufferi...One of the main obstacles for quantum-enhanced metrology is that the estimation accuracy enhanced by non-classical states is likely to be obliterated by noises. Here, we consider a scenario of phase estimation suffering from pure dephasing noise which is taken into account after the phase parameter being imprinted, and propose a scheme to effectively protect the quantum enhancement from both correlated and uncorrelated dephasing sources by performing a rotation operation prior to the noise. By invoking the Fisher information approach, we strictly prove that a π/2 rotation is the ideal one which can completely resist the influence of the phase noise for all real symmetric pure states and the optimal measurement approaching the ultimate sensitivity set by quantum Cramér–Rao bound is presented.Additionally, we numerically study the availability of the scheme with arbitrary angle rotation for different probe states and show that our scheme will still robust for general symmetric pure states even with non-ideal rotation operation.展开更多
This paper deals with the optimal transportation for generalized Lagrangian L = L（x, u, t）, and considers the following cost function： c（x, y） = inf x（0）=x x（1）=y u∈U∫0^1 L（x（s）, u（x（s）, s）, s）ds, w...This paper deals with the optimal transportation for generalized Lagrangian L = L（x, u, t）, and considers the following cost function： c（x, y） = inf x（0）=x x（1）=y u∈U∫0^1 L（x（s）, u（x（s）, s）, s）ds, where U is a control set, and x satisfies the ordinary equation x（s） = f（x（s）, u（x（s）, s））.It is proved that under the condition that the initial measure μ0 is absolutely continuous w.r.t. the Lebesgue measure, the Monge problem has a solution, and the optimal transport map just walks along the characteristic curves of the corresponding Hamilton-Jacobi equation：Vt（t, x） ＋ sup u∈U = 0,V（0, x） = Φ0（x）.展开更多
基金Sponsored by Humanities and Social Sciences Project in Northwest A&F University(2015RWYB38)
文摘Studying tiie urban landscape pattern plays a crucial role in scientific land use and management and in improving the urban ecological environment In this paper, AutoCAD, ArcGIS, Fragstats, and other software were used to analyse the data of the fourth phase of land use in the core atea of Yangling Demonstration Zone. The results showed that： ① in the core area, the percentage of construction land incteased from 18.22% to 61.72%, and the percentage of agricultufal land decreased from 58.36% to 11.14%. And the fafm land was fragmented, and traffic connectivily was strengthened. The afea of garden land was reduced from 251.89 hm2 to 50.38 hm^2, and the landscape metric of forest land showed an inverted V-shaped curve. ②The year 2009 in four phases witnessed the greatest landscape fragmentation, both Edge Density （ED） and Ingest Patch Index （LPI） increased, and human interference enhanced the overall landscape complexity. Measures were fotmulated in terms of deaf development goals, optimized allocation of land resoutces, effective protection of ecological ted lines, and definite ecological responsibility, so as to optimize the urban landscape pattern.
文摘In comparison to the construction of modern highway engineering,several of China’s early pavement construction concerns,such as pavement collapse,are rather clear.Limited by historical and technical factors,the subgrade and pavement design for highways lacks scientificity,thus inducing potential safety problems in the operation.In order to comprehensively improve the subgrade and pavement design as well as ensure the quality and safety of highway engineering projects,this paper takes the reconstructed and expanded highway projects as research subjects and focuses on proposing optimization measures for the subgrade and pavement design of reconstructed and expanded highways,so as to provide adequate reference.
基金supported by Emerging industry leading talent project of Shanxi Province(No.[2020]587)。
文摘Objective:To explore the clinical effect of perioperative nursing guided by the concept of enhanced recovery after surgery and summarize them.Methods:Pubmed,Chinese National Knowledge Infrastructure(CNKI),Chinese Biomedical Literature Database(CBM),Wanfang Database,and VIP Database were searched to obtain the relevant literature involving enhanced recovery after surgery(ERAS)guidance,obtain the effective clinical data,review the reports in literature,and obtain the effective scheme.Results:Compared with the traditional nursing program,perioperative nursing principles guided by the concept of ERAS provide more accurate nursing care to patients and reduce the occurrence of intraoperative stress events through comprehensive nursing measures such as preoperative pre-rehabilitation measures,intraoperative body temperature and fluid management,postoperative analgesia,prevention of nausea and vomiting,early mobilization,catheter nursing,and better out-of-hospital follow-up.Conclusions:Perioperative nursing principles guided by the concept of ERAS can significantly reduce the incidence of perioperative complications,shorten the hospital stay of patients,and promote postoperative rehabilitation of patients.The transformation and implementation of this concept can bring significant benefits to hospitals,medical care,and patients.
文摘In Colleges and universities,the organization of Ideological and political teaching courses can strengthen the ideological education of students,but at present there are still some problems in the ideological and political teaching in Colleges and universities,the ideological and political teaching has not achieved the expected effect,and the ideological and political teaching will be hindered in the work.This paper focuses on the connotation of Ideological and political teaching in Colleges and universities,and puts forward the measures of transformation and upgrading of Ideological and political teaching management.
基金Under the auspices of National Natural Science Foundation of China(No.41501090,41501105)Fundamental Research Funds for Central Universities(No.2412015KJ023)
文摘In order to study the diurnal variation of soil CO2 effiux from temperate meadow steppes in Northeast China, and determine the best time for observation, a field experiment was conducted with a LI-6400 soil CO2 flux system under five typical plant communi- ties （Suaeda glauca （Sg）, Chloris virgata （Cv）, Puecinellia distans （Pd）, Leymus chinensis （Lc） and Phragmites australis （Pa）） and an alkali-spot land （As） at the meadow steppe of western Songnen Plain. The results showed that the diurnal variation of soil CO2 effiux exhibited a single peak curve in the growing season. Diurnal maximum soil respiration （Rs） often appeared between 1 1：00 and 13：00, while the minimum occurred at 21：00-23：00 or before dawn. Air temperature near the soil surface （Ta） and soil temperature at 10 cm depth （Tlo） exerted dominant control on the diurnal variations of soil respiration. The time-windows 7：00-9：00 could be used as the optimal measuring time to represent the daily mean soil CO2 effiux at the Cv, Pd, Lc and Pa sites. The daily mean soil CO2 effiux was close to the soil COz effiux from 15：00 to 17：00 and the mean of 2 individual soil CO2 effiux from 15：00 to 19：00 at the As and Sg sites, respectively. During nocturnal hours, negative soil CO2 fluxes （CO2 downwards into the soil） were frequently observed at the As and Sg sites, the magnitude of the negative CO2 fluxes were 0.10-1.55 gmol/（m2.s） and 0.10-0.69 gmol/（m2.s）at the two sites. The results im- plied that alkaline soils could absorb CO2 under natural condition, which might have significant implications to the global carbon budget accounting.
基金supported by the National Natural Science Foundation of China(Grant Nos.61370194 and 61202082)the Fundamental Research Funds for the Central Universities of China(Grant Nos.BUPT2012RC0219)the Foundation of Science and Technology of Huawei of China
文摘We firstly present a novel scheme for deterministic joint remote state preparation of an arbitrary five-qubit Brown state using four Greenberg-Horme-Zeilinger （GHZ） entangled states as the quantum channel. The success probability of this scheme is up to 1, which is superior to the existing ones. Moreover, the scheme is extended to the generalized case where three-qubit and four-qubit non-maximally entangled states are taken as the quantum channel. We simultaneously employ two common methods to reconstruct the desired state. By comparing these two methods, we draw a conclusion that the first is superior to the second-optimal positive operator-valued measure only taking into account the number of auxiliary particles and the success probability.
基金Project in the “3th Five-Year Plan”for the Development of Philosophy and Social Sciences in Guangzhou(Number:2020GZGJ211).
文摘With the continuous development of modem science and technology,great changes have taken place in the advertising media industry where the traditional form of advertising has gradually changed into digital ones.Compared with the traditional advertising,digital advertising has more flexibility and has a variety of forms in its advertising creation according to product itself.In addition,visual communication design plays a critical role where it is an important way to improve digital advertising.Therefore,it is necessary to optimize visual communication design in order to improve the quality of digital advertising.In this way,this article carries out an in-depth research and analysis on the visual communication design of digital media in digital advertising and put forward some reasonable suggestions and measures,aiming to further promote the development of China's advertising media industry.
基金supported by the National Natural Science Foundation of China(No.11426179)the National Natural Science Foundation of China(Nos.10871132,11271263)+4 种基金the Key Scientific Research Fund of Xihua University(No.z1312624)the Foundation of Sichuan Educational Committee(No.14ZA0112)the Preeminent Youth Fund for School of Science in Xihua Universitythe Beijing Natural Science Foundation(No.1132001)BCMIIS
文摘In this paper, we study optimal recovery （reconstruction） of functions on the sphere in the average case setting. We obtain the asymptotic orders of average sampling numbers of a Sobolev space on the sphere with a Gaussian measure in the Lq （S^d-1） metric for 1 ≤ q ≤ ∞, and show that some worst-case asymptotically optimal algorithms are also asymptotically optimal in the average case setting in the Lq （S^d-1） metric for 1 ≤ q ≤ ∞.
文摘The application of questioning as a teaching tool has always been considered as a main part of the teaching process.Based on the viewpoint of several researchers,a survey was conducted on the application of different questioning strategies by Chinese and foreign EFL teachers in a middle school,in order to determine their effects on students’language learning output and propose measures to optimize Chinese teachers’questioning strategies for improving students’learning efficiency.This research provides preliminary results based on the data collected from the video recordings of class sessions,a questionnaire,and an interview.According to the analysis,the questioning strategies differ between Chinese and foreign EFL teachers in many aspects,such as in information seeking,offering,modification,adjustment,feedback,and so forth.
基金supported by the National Natural Science Foundation of China (Grant No.51975321)EU H2020-MSCA-RISE-ECSASDPE (Grant No.734272)Tsinghua-Jiangyin Innovation Special Fund (Grant No.TJISF 2022JYTH01)。
文摘To improve the efficiency and accuracy of kinematic calibration,the selection of measurement configurations is an important issue.In previous research,optimal measurement configurations mainly are selected by maximizing observability indices.However,the traditional observability indices only focus on the identification efficiency of the error parameters,while the purpose of robot kinematic calibration is to improve accuracy.To solve the inconsistency of the purpose between the observability index and calibration,the concept of the residual index to represent the residual distribution of the end effector after robot kinematic calibration with the measurement noise is proposed.Based on the quadratic form minimization of residuals,this article defines a specific residual index,O^(r),which is dimensionless and strictly better with the increase of measurement configurations.The indices are used to select measurement configurations in the kinematic calibration of a 5-DOF 2UPU/SP-RR hybrid robot,and the calibration results show that the proposed residual index is better than the traditional indices in the accuracy and stability of the end effector residual.
文摘The nonductile reinforced concrete building(NDRCB)stock-typically,pre-1974 structures in the U.S.-is a well-known high-risk group for seismic hazards.Prior studies indicate that there are approximately 1500 NDRCBs in Los Angeles.Through various ordinances,the owners are currently required to choose between demolition and,when appropriate,seismic retrofitting.Because fulfilling these ordinances will take decades,the potential risk of major losses will persist.In this study,a method for automated development of structural analysis models and damage fragilities for non-ductile moment-resisting frames is established.This capability enables seismic risk assessment at a regional scale using relatively limited building metadata and the era-specific seismic design code.The approach is used first to develop archetypal models in OpenSees,verified through static pushover and nonlinear time-history analyses against prior detailed studies.Fragility curves for discrete damage states are developed through a probabilistic seismic demand model.Additional investigations are carried out to consider the influence of soil-structural interaction effects and to determine the most suitable seismic intensity measures to quantify the seismic damage levels of NDRCB frames.The sensitivity of the proposed modeling method to variations/uncertainties in building configurations and properties is also examined through parametric studies.The method is limited to a particular subcategory of NDRBCs-namely,moment-resisting frames-but extensions to other types appear straightforward.
基金supported by the National Special Water Project in China (No. 2008ZX07526-002-01)
文摘The Songhua River Basin is a burgeoning agricultural area in the modern times in China. Particularly in recent years, increasing chemical fertilizers and pesticides have been applied with the development of agricultural production. However, the situation of non- point source pollution （NSP） from agricultural production in this basin is still obscure. In order to solve the problem, the occurrence and distribution of acetochlor in sediments and riparian soils of the Songhua River Basin before rain season and after rain season were investigated. In addition, total organic carbon was analyzed. The result showed that the concentration of acetochlor ranged from 0.47 to 11.76 μg/kg in sediments and 0.03 to 709.37 μg/kg in riparian soils. During the high flow period in 2009, the mean concentration was 4.79 μg/kg in sediments and 0.75 μg]kg in riparian soils, respectively. Similarly, the mean concentration was 2.53 μg/kg in sediments and 61.36μg/kg in riparian soils, during the average flow period in 2010. There was a significant correlation between the concentration of acetochlor and total organic carbon in surface sediments. Moreover, the distribution of acetochlor in sediments of the Songhua River was significantly correlated to land use and topography of the watershed. The investigated data suggested that the concentration of acetochlor in the Songnen Plain and the Sanjiang Plain was higher than that in the other areas of the basin, and riparian buffering zones in these areas bad been destroyed by human activities. The optimal agricultural measures to alleviate the contamination of pesticides should be adopted, including controlling agricultural application of acetochlor and ecological restoration of riparian buffering strips.
基金Supported by the National Natural Science Foundation of China under Grant Nos.61273202,61673389,and 61134008
文摘In this paper we design the following two-step scheme to estimate the model parameter ω0 of the quantum system: first we utilize the Fisher information with respect to an intermediate variable v = cos(ω0 t) to determine an optimal initial state and to seek optimal parameters of the POVM measurement operators; second we explore how to estimate ω0 from v by choosing t when a priori information knowledge of ω0 is available. Our optimal initial state can achieve the maximum quantum Fisher information. The formulation of the optimal time t is obtained and the complete algorithm for parameter estimation is presented. We further explore how the lower bound of the estimation deviation depends on the a priori information of the model.
基金Support by the National Natural Science Foundation of China under Grant No.11475146
文摘One of the main obstacles for quantum-enhanced metrology is that the estimation accuracy enhanced by non-classical states is likely to be obliterated by noises. Here, we consider a scenario of phase estimation suffering from pure dephasing noise which is taken into account after the phase parameter being imprinted, and propose a scheme to effectively protect the quantum enhancement from both correlated and uncorrelated dephasing sources by performing a rotation operation prior to the noise. By invoking the Fisher information approach, we strictly prove that a π/2 rotation is the ideal one which can completely resist the influence of the phase noise for all real symmetric pure states and the optimal measurement approaching the ultimate sensitivity set by quantum Cramér–Rao bound is presented.Additionally, we numerically study the availability of the scheme with arbitrary angle rotation for different probe states and show that our scheme will still robust for general symmetric pure states even with non-ideal rotation operation.
文摘This paper deals with the optimal transportation for generalized Lagrangian L = L（x, u, t）, and considers the following cost function： c（x, y） = inf x（0）=x x（1）=y u∈U∫0^1 L（x（s）, u（x（s）, s）, s）ds, where U is a control set, and x satisfies the ordinary equation x（s） = f（x（s）, u（x（s）, s））.It is proved that under the condition that the initial measure μ0 is absolutely continuous w.r.t. the Lebesgue measure, the Monge problem has a solution, and the optimal transport map just walks along the characteristic curves of the corresponding Hamilton-Jacobi equation：Vt（t, x） ＋ sup u∈U = 0,V（0, x） = Φ0（x）.
