A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in deta...A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in detail. In the measurement, after adjusting a standard 1/4 wave plate and the fast (slow) axis of the plate to be measured parallel to the pass axis of the polarizer, the plate to be measured is rotated by 450 counterclockwisly. A stepping motor is used to rotate the analyzer. The experimental data are collected by a photodetector and then sent to a computer. According to the output data curve, the phase retardation and optic axis of the plate to be measured can be obtained simultaneously. To test the feasibility of the method, a λ /2 and a λ /8 wave plates are used as examples to demonstrate the measurement procedures. The phase retardation measurement accuracy is better than 0.5×10-2. This method can be used to measure the arbitrary phase retardation conveniently.展开更多
We calculate the concurrence and spin squeezing parameter of three atoms induced by a coherent field. It shows that when the mean numbers of photon of the field is very small, concurrence exhibits a certain kind of ap...We calculate the concurrence and spin squeezing parameter of three atoms induced by a coherent field. It shows that when the mean numbers of photon of the field is very small, concurrence exhibits a certain kind of approximative periodic vibration. With the increase of the mean numbers of photon, its periodicity will be interrupted. As for the relationship between the concurrence and spin squeezing, numeric result shows that under Dick model, spin squeezing serves as a sufficient but not necessary condition for concurrence.展开更多
[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds i...[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds in drinking water. [Method]The preparation method of head space was adopted for the volatile organic compounds in drinking water. [Result] The 20 kinds of volatile organic compounds in drinking water all could be detected simultaneously by using HS-GC-FID method,and they all could be separated well. The HS-GC-FID method could analyze the detected substances qualitatively and quantitatively. In addition, this detection method was characterized by larger linear range of concentration, higher precision, higher detection limit and higher recovery rate. [Conclusion] Under certain conditions, HSGC can reduce the loss of volatile organic compound in drinking water and improve the sensitivity of detection. Moreover, the detection results meet the requirements by quality control.展开更多
In the paper, we study effects of scale-free （SF） topology on dynamical synchronization and control in coupled map lattices （CIVIL）. Our strategy is to apply three feedback control methods, including constant feed...In the paper, we study effects of scale-free （SF） topology on dynamical synchronization and control in coupled map lattices （CIVIL）. Our strategy is to apply three feedback control methods, including constant feedback and two types of time-delayed feedback, to a small fraction of network nodes to reach desired synchronous state. Two controlled bifurcation diagrams verses feedback strength are obtained respectively. It is found that the value of critical feedback strength γc for the first time-delayed feedback control is increased linearly as e is increased linearly. The GML with SF loses synchronization and intermittency occurs if γ 〉 γc. Numerical examples are presented to demonstrate all results.展开更多
Wavelet estimation is a common step in seismic data processing and inversion. Homomorphic wavelet estimation has long utilized as a method that uses a seismic stack section with no phase presumption. Forming a stack s...Wavelet estimation is a common step in seismic data processing and inversion. Homomorphic wavelet estimation has long utilized as a method that uses a seismic stack section with no phase presumption. Forming a stack section, normal move-out （NMO） correction must be applied on common midpoint （CMP） gathers, although it introduces NMO stretching. After stacking, residual of the NMO stretching may affect the stack section even after muting the highly stretched zone of the NMO corrected CMP gather. Presence of significant residual NMO stretching changes the spectral characteristics of data in time direction, by different degrees. Considering that in homomorphic process the wavelet is estimated based on the spectral characteristics of data, compensating for the residual NMO stretching, can improve the accuracy of the process. Here, we introduce a fast method of calculating the amount of residual NMO stretching and compensating for its effect on wavelet estimation. The proposed method needs limited prestack information like offsets and velocity function and include no prestack processing. We apply the proposed method on synthetic and real datasets and demonstrate the improvement of the estimated wavelet.展开更多
Objectives: To probe some more important factors affecting the HIV epidemic by surveying the relationshipbetween AIDS high risk behaviors and childhood status,attitude/perception to gender of male/sex orientation andr...Objectives: To probe some more important factors affecting the HIV epidemic by surveying the relationshipbetween AIDS high risk behaviors and childhood status,attitude/perception to gender of male/sex orientation andrare experiences/Psy-chology among Chinese gays. Methods: Data were collected from 240 Chinese gays whowere attracted by their same gender. Results: The extent of sex among China's Mainland gays issimilar to that of industrialized countries, and behaviorsthat exacerbate the HIV epidemic are universal.Perceptions 'being a girl is better',' Dislike toys likeswords or pistols in early childhood were predictors topassive anal intercourse in adulthood. Those gay men whobegan sexual intercourse younger than 16 years old tendedto have more sex partners and suffered more pain. Thosedisliked gender of male or self-regarded as female tended tohave more passive anal intercourse and related to childhoodcross-gender experience/psychology while those were raised as girls by their parentsdid not take on e above characters. Individuals who experienced sex coercion and drug abuse were the twosubgroups with the greatest high-risk behaviors. Individualswho had sex with females had the greatest number of malesex partners and were more prone to group sex. Individualswith pedophilia or gerontophilia had more casual sexpartners. Psychological problems encountered by Chinese Conclusions: The prospect of an extensive AIDSepidemic among Chinese gays does exist and somesubgroups of gays play more important roles in theepidemic. Some high risk behaviors among adult gays canbe foreseen explicitly by the predictors taking on inchildhood, and closely relate to attitude/perception, togender of male, to some rare experience/psychology.展开更多
Mountain area accounts for a high proportion of the land area in China,and it is the focal area to solve the contradiction of imbalanced regional development,as well as an important source of ecosystem services.Theref...Mountain area accounts for a high proportion of the land area in China,and it is the focal area to solve the contradiction of imbalanced regional development,as well as an important source of ecosystem services.Therefore,this area has been facing long-term pressure and challenges in economic development and ecological protection.In this paper,we selected a rocky desertification mountain area,an active mountain area of new tectonic movement and a typical northern earth-rock mountain area,as Qian-Gui karst Mountain area,Hengduan Mountain area and Taihang Mountain area,as examples to represent three main types of mountain areas.Three representative types of ecosystem services,including NPP(Net Primary Productivity)as a support service,water conservation as a regulation service,and agricultural produce as a supply service,were incorporated into this study.Linear regression,correlation analysis and other methods were then used to investigate the spatial-temporal characteristics of the trade-offs and synergies in each of the three kinds of mountain areas during 1990-2015 in China.The analysis yielded three main conclusions for the three mountainous areas.(1)The agricultural produce supply service decreased relatively,while the support and regulation services of NPP and hydrological regulation increased significantly.(2)There was a synergistic relationship between NPP and the hydrological regulation services in the three mountainous areas.The synergistic relation in Qian-Gui karst Mountain area became enhanced,while those in Hengduan and Taihang Mountain areas became weakened,and the former was weakened to a greater extent.There was a trade-off between NPP,the hydrological regulation service and the agricultural produce supply service among the three mountainous areas.In particular,the trade-off between NPP and the agricultural produce supply service in Qian-Gui karst Mountain area became weaker,while those in Hengduan and Taihang Mountain areas were enhanced,and the latter was enhanced to a greater degree.(3)Significant spatial differentiation was evident in the trade-offs and synergies of ecosystem services among the three mountain areas.展开更多
Long-term meteorological observation series are fundamental for reflecting climate changes.However,almost all meteorological stations inevitably undergo relocation or changes in observation instruments,rules,and metho...Long-term meteorological observation series are fundamental for reflecting climate changes.However,almost all meteorological stations inevitably undergo relocation or changes in observation instruments,rules,and methods,which can result in systematic biases in the observation series for corresponding periods.Homogenization is a technique for adjusting these biases in order to assess the true trends in the time series.In recent years,homogenization has shifted its focus from the adjustments to climate mean status to the adjustments to information about climate extremes or extreme weather.Using case analyses of ideal and actual climate series,here we demonstrate the basic idea of homogenization,introduce new understanding obtained from recent studies of homogenization of climate series in China,and raise issues for further studies in this field,especially with regards to climate extremes,uncertainty of the statistical adjustments,and biased physical relationships among different climate variables due to adjustments in single variable series.展开更多
文摘A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in detail. In the measurement, after adjusting a standard 1/4 wave plate and the fast (slow) axis of the plate to be measured parallel to the pass axis of the polarizer, the plate to be measured is rotated by 450 counterclockwisly. A stepping motor is used to rotate the analyzer. The experimental data are collected by a photodetector and then sent to a computer. According to the output data curve, the phase retardation and optic axis of the plate to be measured can be obtained simultaneously. To test the feasibility of the method, a λ /2 and a λ /8 wave plates are used as examples to demonstrate the measurement procedures. The phase retardation measurement accuracy is better than 0.5×10-2. This method can be used to measure the arbitrary phase retardation conveniently.
文摘We calculate the concurrence and spin squeezing parameter of three atoms induced by a coherent field. It shows that when the mean numbers of photon of the field is very small, concurrence exhibits a certain kind of approximative periodic vibration. With the increase of the mean numbers of photon, its periodicity will be interrupted. As for the relationship between the concurrence and spin squeezing, numeric result shows that under Dick model, spin squeezing serves as a sufficient but not necessary condition for concurrence.
文摘[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds in drinking water. [Method]The preparation method of head space was adopted for the volatile organic compounds in drinking water. [Result] The 20 kinds of volatile organic compounds in drinking water all could be detected simultaneously by using HS-GC-FID method,and they all could be separated well. The HS-GC-FID method could analyze the detected substances qualitatively and quantitatively. In addition, this detection method was characterized by larger linear range of concentration, higher precision, higher detection limit and higher recovery rate. [Conclusion] Under certain conditions, HSGC can reduce the loss of volatile organic compound in drinking water and improve the sensitivity of detection. Moreover, the detection results meet the requirements by quality control.
基金The project supported by the Key Program of National Natural Science Foundation of China under Grant No. 70431002 and National Natural Science Foundation of China under Grant Nos. 70371068 and 10247005 The authors thank Drs. Atay and Chun-Guang Li for their useful advices and discussions.
文摘In the paper, we study effects of scale-free （SF） topology on dynamical synchronization and control in coupled map lattices （CIVIL）. Our strategy is to apply three feedback control methods, including constant feedback and two types of time-delayed feedback, to a small fraction of network nodes to reach desired synchronous state. Two controlled bifurcation diagrams verses feedback strength are obtained respectively. It is found that the value of critical feedback strength γc for the first time-delayed feedback control is increased linearly as e is increased linearly. The GML with SF loses synchronization and intermittency occurs if γ 〉 γc. Numerical examples are presented to demonstrate all results.
文摘Wavelet estimation is a common step in seismic data processing and inversion. Homomorphic wavelet estimation has long utilized as a method that uses a seismic stack section with no phase presumption. Forming a stack section, normal move-out （NMO） correction must be applied on common midpoint （CMP） gathers, although it introduces NMO stretching. After stacking, residual of the NMO stretching may affect the stack section even after muting the highly stretched zone of the NMO corrected CMP gather. Presence of significant residual NMO stretching changes the spectral characteristics of data in time direction, by different degrees. Considering that in homomorphic process the wavelet is estimated based on the spectral characteristics of data, compensating for the residual NMO stretching, can improve the accuracy of the process. Here, we introduce a fast method of calculating the amount of residual NMO stretching and compensating for its effect on wavelet estimation. The proposed method needs limited prestack information like offsets and velocity function and include no prestack processing. We apply the proposed method on synthetic and real datasets and demonstrate the improvement of the estimated wavelet.
文摘Objectives: To probe some more important factors affecting the HIV epidemic by surveying the relationshipbetween AIDS high risk behaviors and childhood status,attitude/perception to gender of male/sex orientation andrare experiences/Psy-chology among Chinese gays. Methods: Data were collected from 240 Chinese gays whowere attracted by their same gender. Results: The extent of sex among China's Mainland gays issimilar to that of industrialized countries, and behaviorsthat exacerbate the HIV epidemic are universal.Perceptions 'being a girl is better',' Dislike toys likeswords or pistols in early childhood were predictors topassive anal intercourse in adulthood. Those gay men whobegan sexual intercourse younger than 16 years old tendedto have more sex partners and suffered more pain. Thosedisliked gender of male or self-regarded as female tended tohave more passive anal intercourse and related to childhoodcross-gender experience/psychology while those were raised as girls by their parentsdid not take on e above characters. Individuals who experienced sex coercion and drug abuse were the twosubgroups with the greatest high-risk behaviors. Individualswho had sex with females had the greatest number of malesex partners and were more prone to group sex. Individualswith pedophilia or gerontophilia had more casual sexpartners. Psychological problems encountered by Chinese Conclusions: The prospect of an extensive AIDSepidemic among Chinese gays does exist and somesubgroups of gays play more important roles in theepidemic. Some high risk behaviors among adult gays canbe foreseen explicitly by the predictors taking on inchildhood, and closely relate to attitude/perception, togender of male, to some rare experience/psychology.
基金The National Natural Science Foundation of China(41771115)National Key Basic Research and Development Program(2015CB452706)Guizhou Science and Technology Fund(Guizhou Technology Cooperation Basis 20181116)。
文摘Mountain area accounts for a high proportion of the land area in China,and it is the focal area to solve the contradiction of imbalanced regional development,as well as an important source of ecosystem services.Therefore,this area has been facing long-term pressure and challenges in economic development and ecological protection.In this paper,we selected a rocky desertification mountain area,an active mountain area of new tectonic movement and a typical northern earth-rock mountain area,as Qian-Gui karst Mountain area,Hengduan Mountain area and Taihang Mountain area,as examples to represent three main types of mountain areas.Three representative types of ecosystem services,including NPP(Net Primary Productivity)as a support service,water conservation as a regulation service,and agricultural produce as a supply service,were incorporated into this study.Linear regression,correlation analysis and other methods were then used to investigate the spatial-temporal characteristics of the trade-offs and synergies in each of the three kinds of mountain areas during 1990-2015 in China.The analysis yielded three main conclusions for the three mountainous areas.(1)The agricultural produce supply service decreased relatively,while the support and regulation services of NPP and hydrological regulation increased significantly.(2)There was a synergistic relationship between NPP and the hydrological regulation services in the three mountainous areas.The synergistic relation in Qian-Gui karst Mountain area became enhanced,while those in Hengduan and Taihang Mountain areas became weakened,and the former was weakened to a greater extent.There was a trade-off between NPP,the hydrological regulation service and the agricultural produce supply service among the three mountainous areas.In particular,the trade-off between NPP and the agricultural produce supply service in Qian-Gui karst Mountain area became weaker,while those in Hengduan and Taihang Mountain areas were enhanced,and the latter was enhanced to a greater degree.(3)Significant spatial differentiation was evident in the trade-offs and synergies of ecosystem services among the three mountain areas.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05090105)the R&D Special Fund for Public Welfare Industry(Meteorology)(Grant No.GYHY201206013)the National Key Technology R&D program(Grant No.2012BAC22B04)
文摘Long-term meteorological observation series are fundamental for reflecting climate changes.However,almost all meteorological stations inevitably undergo relocation or changes in observation instruments,rules,and methods,which can result in systematic biases in the observation series for corresponding periods.Homogenization is a technique for adjusting these biases in order to assess the true trends in the time series.In recent years,homogenization has shifted its focus from the adjustments to climate mean status to the adjustments to information about climate extremes or extreme weather.Using case analyses of ideal and actual climate series,here we demonstrate the basic idea of homogenization,introduce new understanding obtained from recent studies of homogenization of climate series in China,and raise issues for further studies in this field,especially with regards to climate extremes,uncertainty of the statistical adjustments,and biased physical relationships among different climate variables due to adjustments in single variable series.
