The tango of life begins with the very first cell division.New research reveals that to dance their way through development,dividing cells must pass along not just DNA but molecular“memories”that guide their destini...The tango of life begins with the very first cell division.New research reveals that to dance their way through development,dividing cells must pass along not just DNA but molecular“memories”that guide their destinies.When this handoff gets fumbled,the dance falls apart.展开更多
The seasonality and day-to-day variation of near-surface temperature patterns can greatly control nearly all physical and biological processes though temperature predictions at such scales remain challenging. This pap...The seasonality and day-to-day variation of near-surface temperature patterns can greatly control nearly all physical and biological processes though temperature predictions at such scales remain challenging. This paper implements a simple analytical approach in order to generate daily average temperatures which implicitly accounts for surface heating and drivers through a comprehensive representation of station-based temperature records on a universal standard calendar propagated by the earth’s dynamics features. The modeled and observed pattern of daily temperatures exhibits a close agreement with the level of strength agreement exceeding 0.56. The extreme high and low values of the observed temperature patterns are equally well captured although model underestimates the probability of temperatures around the two modal peaks (~25.6℃ and 27.5℃). Additionally, a theoretical thermal-based division led to the identification of six seasons, including two hot and cold periods along with two pairs of mixed hot-cold. The theoretical division proposed here appears to be a good approximation for the understanding of rainfall seasonality in this area.展开更多
This paper provides a method of the process of computation called the cumulative method, it is based upon repeated cumulative process. The cumulative method is being adapted to the purposes of computation, particularl...This paper provides a method of the process of computation called the cumulative method, it is based upon repeated cumulative process. The cumulative method is being adapted to the purposes of computation, particularly multiplication and division. The operations of multiplication and division are represented by algebraic formulas. An advantage of the method is that the cumulative process can be performed on decimal numbers. The present paper aims to establish a basic and useful formula valid for the two fundamental arithmetic operations of multiplication and division. The new cumulative method proved to be more flexible and made it possible to extend the multiplication and division based on repeated addition/subtraction to decimal numbers.展开更多
Landslide susceptibility assessment is an essential tool for disaster prevention and management. In areas with multiple fault zones, the impact of fault zone on slope stability cannot be disregarded. This study perfor...Landslide susceptibility assessment is an essential tool for disaster prevention and management. In areas with multiple fault zones, the impact of fault zone on slope stability cannot be disregarded. This study performed qualitative analysis of fault zones and proposed a zoning method to assess the landslide susceptibility in Chengkou County, Chongqing Municipality, China. The region within a distance of 1 km from the faults was designated as sub-zone A, while the remaining area was labeled as sub-zone B. To accomplish the assessment, a dataset comprising 388 historical landslides and 388 non-landslide points was used to train the random forest model. 10-fold cross-validation was utilized to select the training and testing datasets for the model. The results of the models were analyzed and discussed, with a focus on model performance and prediction uncertainty. By implementing the proposed division strategy based on fault zone, the accuracy, precision, recall, F-score, and AUC of both two sub-zones surpassed those of the whole region. In comparison to the results obtained for the whole region, sub-zone B exhibited an increase in AUC by 6.15%, while sub-zone A demonstrated a corresponding increase of 1.66%. Moreover, the results of 100 random realizations indicated that the division strategy has little effect on the prediction uncertainty. This study introduces a novel approach to enhance the prediction accuracy of the landslide susceptibility mapping model in areas with multiple fault zones.展开更多
The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration potential.Due to the special geological evolutionary background of the Beira High in the Zamb...The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration potential.Due to the special geological evolutionary background of the Beira High in the Zambezi Delta basin,it has a low gravity anomaly,and the existing seismic survey lines do not cover the whole basin;therefore,it is difficult to interpret the structural characteristics of the whole basin based solely on gravity or seismic data.Based on satellite altimetry gravity anomaly data,this study infers the distribution characteristics of faults in the Zambezi Delta basin by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)technique.Then,constrained by seismic data,the gravity anomaly at the Moho interface is extracted by using the fast forward method of the double-interface model of the gravity anomaly,and this anomaly is then removed from the Bouguer gravity anomaly to obtain the sedimentary layer gravity anomaly.The thickness of the sedimentary strata is obtained by inversing the sedimentary basement depth of the whole basin.Then,uplifts and depressions are divided based on a sedimentary layer thickness of 3 km.This research demonstrates that the Zambezi Delta basin mainly features nearly SN-trending and NE-trending faults and that these faults exhibit east-west partitioning.The nearly SN-trending strike-slip faults controlled the sedimentary development of the basin,and the NE-trending tensile faults may have acted as migration channels for oil,gas and magma.The“overcompensation”effect of the Moho interface gravity anomaly on the gravity anomaly of the sedimentary layer is caused by the depression of the Moho interface beneath the Beira High,which results in a low gravity anomaly value for the Beira High.The pattern of uplifts and depressions trends NE and has the structural characteristics of east-west blocks.展开更多
Seismo-tectonic areas of historical strong earthquakes with MS(7 along Xianshuihe-Xiaojiang fault zone are divided, and their individual fault-pattern and tectonic geomorphology are analyzed. Those strong-earthquake a...Seismo-tectonic areas of historical strong earthquakes with MS(7 along Xianshuihe-Xiaojiang fault zone are divided, and their individual fault-pattern and tectonic geomorphology are analyzed. Those strong-earthquake areas are located in some special parts of the fault zone, where the major branch-faults of the fault zone form left stepping, parallel, and fork-like patterns. In the strong-earthquake areas structurally complicated basins are developed, such as pull-apart basins in fork-like area, in double stepping area, and in stepping and fork-like areas.展开更多
Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface ho...Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.展开更多
The Belle Corporation is a Chinese domestic shoe maker and seller. It also belongs to an industry that has come to be representative of the ubiquitous "Made in China" label. One of the main reasons the compa...The Belle Corporation is a Chinese domestic shoe maker and seller. It also belongs to an industry that has come to be representative of the ubiquitous "Made in China" label. One of the main reasons the company is favored by global investors is due to its unique business pattern-a pattern that sets manufacturing as its base and is active in exploring industrial chain downstream links and establishing its own individual retail channels. Ever since its first inception in the stock market, Belle has set out to acquire several upstream manufacturing companies, indicating its desire for increasing channel terminals. Using a vertically integrated competition strategy, Belle stands out amongst its rivals as being particularly successful in the non-mainstream manufacturing sector. Consequently, its business practices can be used as a model for other domestic manufacturing companies in their efforts to meet the challenges posed by globalization.展开更多
Quantum key distribution(QKD) generates information-theoretical secure keys between two parties based on the physical laws of quantum mechanics. The phase-matching(PM) QKD protocol allows the key rate to break the qua...Quantum key distribution(QKD) generates information-theoretical secure keys between two parties based on the physical laws of quantum mechanics. The phase-matching(PM) QKD protocol allows the key rate to break the quantum channel secret key capacity limit without quantum repeaters, and the security of the protocol is demonstrated by using equivalent entanglement. In this paper, the wavelength division multiplexing(WDM) technique is applied to the PM-QKD protocol considering the effect of crosstalk noise on the secret key rate. The performance of PM-QKD protocol based on WDM with the influence of adjacent classical channels and Raman scattering is analyzed by numerical simulations to maximize the total secret key rate of the QKD, providing a reference for future implementations of QKD based on WDM techniques.展开更多
We say a divisien (S = SA or SB, g) is equal if it divides set S into two subsets SA and SB satisfying f (SA) = f (SB), where f is som attribute function on these sets and SA or SB need not be empty. In the present pa...We say a divisien (S = SA or SB, g) is equal if it divides set S into two subsets SA and SB satisfying f (SA) = f (SB), where f is som attribute function on these sets and SA or SB need not be empty. In the present paper, we have obtained some equal divisions on set of ordered tree with n modes: two equal divisions on tree set; two equal divisions on node set; two divisions on leaf set, one is equal, another one is ''asymptotically'' equal. We conclude that, ordered tree set is on its good behavior in equal dividing.展开更多
In Cambodia,fishery co-management is an important process to transfer authority and ownership to the communities along the Tonle Sap Lake to manage fishery.This paper aims to determine why the co-management of small-s...In Cambodia,fishery co-management is an important process to transfer authority and ownership to the communities along the Tonle Sap Lake to manage fishery.This paper aims to determine why the co-management of small-scale fishery has not been implemented satisfactorily in the Tonle Sap Lake of Cambodia.The research was primarily based on a household survey among 404 house-holds for quantitative data,equally divided between the Cham(202 households)and Khmer(202 households).Participatory process was also applied to collect qualitative data from key stake-holders.We found that limited interaction among the involved stakeholders,i.e.,unequal distribution of authority and resources co-management,has impeded implementation.The engagement of fisherfolk was influenced by dependence on fishery,law enforcement,and events organized by the communities.While the Khmer had better opportunities to participate in planning at the provincial and district levels,the Cham were only engaged in local development activities initiated by their people.However,the latter evinced a higher rate of satisfaction due to their access tofishery resources and to a large quantity of fishing gear.In the future,efforts should be made to:(1)improve resource and authority sharing among all key stakeholders;(2)urgently resolve issues pertinent to capacity building,insufficient budgets for commune councils(CoCs)and community fishery(CFi);and(3)urge law enforcement regarding illegal fishing.展开更多
Guo Moruo (Kuo Mojo, 1892-1978), specialist in Chinese history, philologist, writer and social activist. His original name was Kuo Kaizhen and his self-styled name was Shangwu. On November 16 1892, he was born in the ...Guo Moruo (Kuo Mojo, 1892-1978), specialist in Chinese history, philologist, writer and social activist. His original name was Kuo Kaizhen and his self-styled name was Shangwu. On November 16 1892, he was born in the town of Shawan in Leshan County, Sichuan Province.From the autumn.of 1907 to the summer of 1913, he was a pupil at the Jiadingfu Middle School and the展开更多
Administrative division is an important means of political power reorganization and management,resource integration and optimal allocation,which profoundly shapes the spatial layout of urban development in China.To cl...Administrative division is an important means of political power reorganization and management,resource integration and optimal allocation,which profoundly shapes the spatial layout of urban development in China.To clarify and compare differences between counties,county-level cities and municipal districts is the primary premise for the study of administrative division and urban development.This paper analyzes the institutional differences between counties and county-level cities,as well as counties,county-level cities and municipal districts,from the aspects of organizational structure,urban construction planning,land management,finance,taxation and public services.The research shows that the establishment of counties,county-level cities and municipal districts adapt to different levels and stages of economic and social development,and the conversion from county to county-level city and the conversion from county(or county-level city)to municipal district are both important transformation ways to change their administrative systems,which has different management system and operation pattern.At the same time,the transformation of county-level administrative region is also a“double-edged sword”,we should think about the administrative system as a whole to decide whether it should be adjusted,and effectively respond to the actual needs of local economic and social development.展开更多
The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle m...The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle model. With the new model, the statistical correspondence between the production decline stage and the reserve-production imbalance is clarified,and the correlation of water cut with the recovery percent of recoverable reserves is discussed, providing quantitative basis of reservoir engineering for dividing development stages of oilfield and defining mature oilfields. According to the statistics of oilfields in eastern China, the time point corresponding to the reserve-production balance coefficient dropping to less than 1dramatically is well correlated the beginning point of production decline, thus the time when the reserve-production balance coefficient drops dramatically can be taken as the initiation point of production decline stage. The research results show that the water cut and the recovery percent of recoverable reserves have a good statistical match in the high water cut stage, and it is more rational to take both the start point of production decline stage and the water cut of 90%(or the recovery percent of recoverable reserves of 80%) as the critical criteria for defining a mature oilfield. Five production evolution patterns can be summarized as follows: growth–peak plateau–stepped decline, growth–stepped stabilizing–stepped decline, growth–stepped stabilizing–rapid decline, growth–peak plateau–rapid decline, and growth–continuous decline.展开更多
The Academic Divisions of the Chinese Academy of Sciences (CAS) are vitally important and integral parts of the academy and were founded in June 1, 1955, six years after the establishment of the CAS. This was an impor...The Academic Divisions of the Chinese Academy of Sciences (CAS) are vitally important and integral parts of the academy and were founded in June 1, 1955, six years after the establishment of the CAS. This was an important event for both the CAS and the Chinese S&T community. The institution, which is composed of the most excellent Chinese scientists, has played an active role in strengthening the academic leadership of China’s S&T undertakings. Over the 40-odd years of ups and downs, the development of Academic Divisions could be characterized by four phases: laying the foundation展开更多
The PBFT (Practical Byzantine Fault Tolerance, PBFT) consensus algorithm, which addressed the issue of malicious nodes sending error messages to disrupt the system operation in distributed systems, was challenging to ...The PBFT (Practical Byzantine Fault Tolerance, PBFT) consensus algorithm, which addressed the issue of malicious nodes sending error messages to disrupt the system operation in distributed systems, was challenging to support massive network nodes, the common participation over all nodes in the consensus mechanism would lead to increased communication complexity, and the arbitrary selection of master nodes would also lead to inefficient consensus. This paper offered a PBFT consensus method (Role Division-based Practical Byzantine Fault Tolerance, RD-PBFT) to address the above problems based on node role division. First, the nodes in the system voted with each other to divide the high reputation group and low reputation group, and determined the starting reputation value of the nodes. Then, the mobile node in the group was divided into roles according to the high reputation value, and a total of three roles were divided into consensus node, backup node, and supervisory node to reduce the number of nodes involved in the consensus process and reduced the complexity of communication. In addition, an adaptive method was used to select the master nodes in the consensus process, and an integer value was introduced to ensure the unpredictability and equality of the master node selection. Experimentally, it was verified that the algorithm has lower communication complexity and better decentralization characteristics compared with the PBFT consensus algorithm, which improved the efficiency of consensus.展开更多
In January 1984, the Academic Divisions of the CAS,which was established in 1955, held its fifth General Assembly after experiencing 30 years of trials and hardships, marking the beginning of a new period of flourishi...In January 1984, the Academic Divisions of the CAS,which was established in 1955, held its fifth General Assembly after experiencing 30 years of trials and hardships, marking the beginning of a new period of flourishing development.Ten years passed between the fifth assembly and the seventh one,which was held in June 1994.It was in this decade that the Academic Divisions gradually assumed the practice of the international science community according to the domestic situation and international convention by making clear the nature and functions of the Academic Divisions and of their Members, renaming Division Mem-展开更多
On the eve of the 11th General Assembly of the Chinese Academy of Sciences (CAS), the CAS Presidium briefed the press on the important advances achieved by the Academic Divisions (ADs) over the past two years.
In line with the overall Objectives set out in the"Outline Scheme for the Academic Divisions of theChinese Academy of Sciences (CAS) during theNinth Five-year Plan (1996-2000)," CAS has donea good job of the...In line with the overall Objectives set out in the"Outline Scheme for the Academic Divisions of theChinese Academy of Sciences (CAS) during theNinth Five-year Plan (1996-2000)," CAS has donea good job of the supplementary election of CASmembers and the development of the virtues ofscience and fine style of research. In addihon, con-sultation and appraisal, academic exchanges, andthe popularization of science have progressivelybeen focuses of the academic divisions, and manyaccomplishments have been achieved in these areas.展开更多
1.Election of New Members
In 2001, 56 scientists were elected new CAS members, including l0 in the Division of Mathematics & Physics, 10 in the Division of Chemistry, 12 in the Division of Biology, nine i... 1.Election of New Members
In 2001, 56 scientists were elected new CAS members, including l0 in the Division of Mathematics & Physics, 10 in the Division of Chemistry, 12 in the Division of Biology, nine in the Division of Earth Sciences and 15 in the Division of Engineering Sciences.The average age of the new members is 60.4, and the youngest one is 38 years old. They are now working in nine provinces or municipalities, or governmental departments under the State Council, including 23 outstanding experts working for the CAS.
……展开更多
文摘The tango of life begins with the very first cell division.New research reveals that to dance their way through development,dividing cells must pass along not just DNA but molecular“memories”that guide their destinies.When this handoff gets fumbled,the dance falls apart.
文摘The seasonality and day-to-day variation of near-surface temperature patterns can greatly control nearly all physical and biological processes though temperature predictions at such scales remain challenging. This paper implements a simple analytical approach in order to generate daily average temperatures which implicitly accounts for surface heating and drivers through a comprehensive representation of station-based temperature records on a universal standard calendar propagated by the earth’s dynamics features. The modeled and observed pattern of daily temperatures exhibits a close agreement with the level of strength agreement exceeding 0.56. The extreme high and low values of the observed temperature patterns are equally well captured although model underestimates the probability of temperatures around the two modal peaks (~25.6℃ and 27.5℃). Additionally, a theoretical thermal-based division led to the identification of six seasons, including two hot and cold periods along with two pairs of mixed hot-cold. The theoretical division proposed here appears to be a good approximation for the understanding of rainfall seasonality in this area.
文摘This paper provides a method of the process of computation called the cumulative method, it is based upon repeated cumulative process. The cumulative method is being adapted to the purposes of computation, particularly multiplication and division. The operations of multiplication and division are represented by algebraic formulas. An advantage of the method is that the cumulative process can be performed on decimal numbers. The present paper aims to establish a basic and useful formula valid for the two fundamental arithmetic operations of multiplication and division. The new cumulative method proved to be more flexible and made it possible to extend the multiplication and division based on repeated addition/subtraction to decimal numbers.
基金Postdoctoral Research Foundation of China (2021M700608)Natural Science Foundation Project of Chongqing, Chongqing Science and Technology Commission (cstc2021jcyj-bsh0047)+1 种基金Scientific Project Supported by the Bureau of Planning and Natural Resources, Chongqing (2301DH09002)Sichuan Transportation Science and Technology Project (2018ZL-01)。
文摘Landslide susceptibility assessment is an essential tool for disaster prevention and management. In areas with multiple fault zones, the impact of fault zone on slope stability cannot be disregarded. This study performed qualitative analysis of fault zones and proposed a zoning method to assess the landslide susceptibility in Chengkou County, Chongqing Municipality, China. The region within a distance of 1 km from the faults was designated as sub-zone A, while the remaining area was labeled as sub-zone B. To accomplish the assessment, a dataset comprising 388 historical landslides and 388 non-landslide points was used to train the random forest model. 10-fold cross-validation was utilized to select the training and testing datasets for the model. The results of the models were analyzed and discussed, with a focus on model performance and prediction uncertainty. By implementing the proposed division strategy based on fault zone, the accuracy, precision, recall, F-score, and AUC of both two sub-zones surpassed those of the whole region. In comparison to the results obtained for the whole region, sub-zone B exhibited an increase in AUC by 6.15%, while sub-zone A demonstrated a corresponding increase of 1.66%. Moreover, the results of 100 random realizations indicated that the division strategy has little effect on the prediction uncertainty. This study introduces a novel approach to enhance the prediction accuracy of the landslide susceptibility mapping model in areas with multiple fault zones.
基金The Petrochina Basic Prospective Science and Technology Research Project–Overseas deepwater ultra-deepwater oil and gas exploration technology research topic,under contract No.2021DJ2403。
文摘The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration potential.Due to the special geological evolutionary background of the Beira High in the Zambezi Delta basin,it has a low gravity anomaly,and the existing seismic survey lines do not cover the whole basin;therefore,it is difficult to interpret the structural characteristics of the whole basin based solely on gravity or seismic data.Based on satellite altimetry gravity anomaly data,this study infers the distribution characteristics of faults in the Zambezi Delta basin by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)technique.Then,constrained by seismic data,the gravity anomaly at the Moho interface is extracted by using the fast forward method of the double-interface model of the gravity anomaly,and this anomaly is then removed from the Bouguer gravity anomaly to obtain the sedimentary layer gravity anomaly.The thickness of the sedimentary strata is obtained by inversing the sedimentary basement depth of the whole basin.Then,uplifts and depressions are divided based on a sedimentary layer thickness of 3 km.This research demonstrates that the Zambezi Delta basin mainly features nearly SN-trending and NE-trending faults and that these faults exhibit east-west partitioning.The nearly SN-trending strike-slip faults controlled the sedimentary development of the basin,and the NE-trending tensile faults may have acted as migration channels for oil,gas and magma.The“overcompensation”effect of the Moho interface gravity anomaly on the gravity anomaly of the sedimentary layer is caused by the depression of the Moho interface beneath the Beira High,which results in a low gravity anomaly value for the Beira High.The pattern of uplifts and depressions trends NE and has the structural characteristics of east-west blocks.
基金Chinese Joint Seismological Science Foundation (9507424). Contribution No. 2001A003, Institute of Crustal Dynamics, China Seis
文摘Seismo-tectonic areas of historical strong earthquakes with MS(7 along Xianshuihe-Xiaojiang fault zone are divided, and their individual fault-pattern and tectonic geomorphology are analyzed. Those strong-earthquake areas are located in some special parts of the fault zone, where the major branch-faults of the fault zone form left stepping, parallel, and fork-like patterns. In the strong-earthquake areas structurally complicated basins are developed, such as pull-apart basins in fork-like area, in double stepping area, and in stepping and fork-like areas.
基金the National Key R&D Program of China(2021YFA1401200)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910007022)+2 种基金National Natural Science Foundation of China(No.U21A20140,No.92050117)Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z211100004821009)X.Li acknowledges the support from Beijing Institute of Technology Research Fund Program for Young Scholars(XSQD-201904005).
文摘Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.
文摘The Belle Corporation is a Chinese domestic shoe maker and seller. It also belongs to an industry that has come to be representative of the ubiquitous "Made in China" label. One of the main reasons the company is favored by global investors is due to its unique business pattern-a pattern that sets manufacturing as its base and is active in exploring industrial chain downstream links and establishing its own individual retail channels. Ever since its first inception in the stock market, Belle has set out to acquire several upstream manufacturing companies, indicating its desire for increasing channel terminals. Using a vertically integrated competition strategy, Belle stands out amongst its rivals as being particularly successful in the non-mainstream manufacturing sector. Consequently, its business practices can be used as a model for other domestic manufacturing companies in their efforts to meet the challenges posed by globalization.
基金supported by the State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications) (Grant No. IPOC2021ZT10)the National Natural Science Foundation of China (Grant No. 11904333)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. 2019XDA02)BUPT Innovation and Entrepreneurship Support Program (Grant No. 2022-YC-T051)。
文摘Quantum key distribution(QKD) generates information-theoretical secure keys between two parties based on the physical laws of quantum mechanics. The phase-matching(PM) QKD protocol allows the key rate to break the quantum channel secret key capacity limit without quantum repeaters, and the security of the protocol is demonstrated by using equivalent entanglement. In this paper, the wavelength division multiplexing(WDM) technique is applied to the PM-QKD protocol considering the effect of crosstalk noise on the secret key rate. The performance of PM-QKD protocol based on WDM with the influence of adjacent classical channels and Raman scattering is analyzed by numerical simulations to maximize the total secret key rate of the QKD, providing a reference for future implementations of QKD based on WDM techniques.
基金Supported by China National Natural Science Foundation.
文摘We say a divisien (S = SA or SB, g) is equal if it divides set S into two subsets SA and SB satisfying f (SA) = f (SB), where f is som attribute function on these sets and SA or SB need not be empty. In the present paper, we have obtained some equal divisions on set of ordered tree with n modes: two equal divisions on tree set; two equal divisions on node set; two divisions on leaf set, one is equal, another one is ''asymptotically'' equal. We conclude that, ordered tree set is on its good behavior in equal dividing.
文摘In Cambodia,fishery co-management is an important process to transfer authority and ownership to the communities along the Tonle Sap Lake to manage fishery.This paper aims to determine why the co-management of small-scale fishery has not been implemented satisfactorily in the Tonle Sap Lake of Cambodia.The research was primarily based on a household survey among 404 house-holds for quantitative data,equally divided between the Cham(202 households)and Khmer(202 households).Participatory process was also applied to collect qualitative data from key stake-holders.We found that limited interaction among the involved stakeholders,i.e.,unequal distribution of authority and resources co-management,has impeded implementation.The engagement of fisherfolk was influenced by dependence on fishery,law enforcement,and events organized by the communities.While the Khmer had better opportunities to participate in planning at the provincial and district levels,the Cham were only engaged in local development activities initiated by their people.However,the latter evinced a higher rate of satisfaction due to their access tofishery resources and to a large quantity of fishing gear.In the future,efforts should be made to:(1)improve resource and authority sharing among all key stakeholders;(2)urgently resolve issues pertinent to capacity building,insufficient budgets for commune councils(CoCs)and community fishery(CFi);and(3)urge law enforcement regarding illegal fishing.
文摘Guo Moruo (Kuo Mojo, 1892-1978), specialist in Chinese history, philologist, writer and social activist. His original name was Kuo Kaizhen and his self-styled name was Shangwu. On November 16 1892, he was born in the town of Shawan in Leshan County, Sichuan Province.From the autumn.of 1907 to the summer of 1913, he was a pupil at the Jiadingfu Middle School and the
基金This research was funded by National Natural Science Foundation of China,grant number 41871151.
文摘Administrative division is an important means of political power reorganization and management,resource integration and optimal allocation,which profoundly shapes the spatial layout of urban development in China.To clarify and compare differences between counties,county-level cities and municipal districts is the primary premise for the study of administrative division and urban development.This paper analyzes the institutional differences between counties and county-level cities,as well as counties,county-level cities and municipal districts,from the aspects of organizational structure,urban construction planning,land management,finance,taxation and public services.The research shows that the establishment of counties,county-level cities and municipal districts adapt to different levels and stages of economic and social development,and the conversion from county to county-level city and the conversion from county(or county-level city)to municipal district are both important transformation ways to change their administrative systems,which has different management system and operation pattern.At the same time,the transformation of county-level administrative region is also a“double-edged sword”,we should think about the administrative system as a whole to decide whether it should be adjusted,and effectively respond to the actual needs of local economic and social development.
基金Supported by the National Natural Science Foundation of China (72088101)。
文摘The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle model. With the new model, the statistical correspondence between the production decline stage and the reserve-production imbalance is clarified,and the correlation of water cut with the recovery percent of recoverable reserves is discussed, providing quantitative basis of reservoir engineering for dividing development stages of oilfield and defining mature oilfields. According to the statistics of oilfields in eastern China, the time point corresponding to the reserve-production balance coefficient dropping to less than 1dramatically is well correlated the beginning point of production decline, thus the time when the reserve-production balance coefficient drops dramatically can be taken as the initiation point of production decline stage. The research results show that the water cut and the recovery percent of recoverable reserves have a good statistical match in the high water cut stage, and it is more rational to take both the start point of production decline stage and the water cut of 90%(or the recovery percent of recoverable reserves of 80%) as the critical criteria for defining a mature oilfield. Five production evolution patterns can be summarized as follows: growth–peak plateau–stepped decline, growth–stepped stabilizing–stepped decline, growth–stepped stabilizing–rapid decline, growth–peak plateau–rapid decline, and growth–continuous decline.
文摘The Academic Divisions of the Chinese Academy of Sciences (CAS) are vitally important and integral parts of the academy and were founded in June 1, 1955, six years after the establishment of the CAS. This was an important event for both the CAS and the Chinese S&T community. The institution, which is composed of the most excellent Chinese scientists, has played an active role in strengthening the academic leadership of China’s S&T undertakings. Over the 40-odd years of ups and downs, the development of Academic Divisions could be characterized by four phases: laying the foundation
文摘The PBFT (Practical Byzantine Fault Tolerance, PBFT) consensus algorithm, which addressed the issue of malicious nodes sending error messages to disrupt the system operation in distributed systems, was challenging to support massive network nodes, the common participation over all nodes in the consensus mechanism would lead to increased communication complexity, and the arbitrary selection of master nodes would also lead to inefficient consensus. This paper offered a PBFT consensus method (Role Division-based Practical Byzantine Fault Tolerance, RD-PBFT) to address the above problems based on node role division. First, the nodes in the system voted with each other to divide the high reputation group and low reputation group, and determined the starting reputation value of the nodes. Then, the mobile node in the group was divided into roles according to the high reputation value, and a total of three roles were divided into consensus node, backup node, and supervisory node to reduce the number of nodes involved in the consensus process and reduced the complexity of communication. In addition, an adaptive method was used to select the master nodes in the consensus process, and an integer value was introduced to ensure the unpredictability and equality of the master node selection. Experimentally, it was verified that the algorithm has lower communication complexity and better decentralization characteristics compared with the PBFT consensus algorithm, which improved the efficiency of consensus.
文摘In January 1984, the Academic Divisions of the CAS,which was established in 1955, held its fifth General Assembly after experiencing 30 years of trials and hardships, marking the beginning of a new period of flourishing development.Ten years passed between the fifth assembly and the seventh one,which was held in June 1994.It was in this decade that the Academic Divisions gradually assumed the practice of the international science community according to the domestic situation and international convention by making clear the nature and functions of the Academic Divisions and of their Members, renaming Division Mem-
文摘On the eve of the 11th General Assembly of the Chinese Academy of Sciences (CAS), the CAS Presidium briefed the press on the important advances achieved by the Academic Divisions (ADs) over the past two years.
文摘In line with the overall Objectives set out in the"Outline Scheme for the Academic Divisions of theChinese Academy of Sciences (CAS) during theNinth Five-year Plan (1996-2000)," CAS has donea good job of the supplementary election of CASmembers and the development of the virtues ofscience and fine style of research. In addihon, con-sultation and appraisal, academic exchanges, andthe popularization of science have progressivelybeen focuses of the academic divisions, and manyaccomplishments have been achieved in these areas.
文摘 1.Election of New Members
In 2001, 56 scientists were elected new CAS members, including l0 in the Division of Mathematics & Physics, 10 in the Division of Chemistry, 12 in the Division of Biology, nine in the Division of Earth Sciences and 15 in the Division of Engineering Sciences.The average age of the new members is 60.4, and the youngest one is 38 years old. They are now working in nine provinces or municipalities, or governmental departments under the State Council, including 23 outstanding experts working for the CAS.
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