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The Cumulative Method for Multiplication and Division
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作者 Muna Mohammed Hammuda 《Applied Mathematics》 2024年第5期349-354,共6页
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
关键词 Multiplication and division Cumulative Method Repeated Process Decimal Numbers
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Machine learning solution for regional landslide susceptibility based on fault zone division strategy
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作者 WANG Yunhao WANG Luqi +5 位作者 LIU Songlin SUN Weixin LIU Pengfei ZHU Lin YANG Wenyu GUO Tong 《Journal of Mountain Science》 SCIE CSCD 2024年第5期1745-1760,共16页
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
关键词 Landslide susceptibility mapping Fault division strategy Random forest GIS
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Cell division cyclin 25C knockdown inhibits hepatocellular carcinoma development by inducing endoplasmic reticulum stress
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作者 Yan-Fei Li Fang-Yuan Zheng +4 位作者 Xin-Yu Miao Hai-Long Liu Yao-Yao Zhang Nai-Xia Chao Fa-Rong Mo 《World Journal of Gastroenterology》 SCIE CAS 2024年第19期2564-2574,共11页
BACKGROUND Cell division cyclin 25C(CDC25C)is a protein that plays a critical role in the cell cycle,specifically in the transition from the G2 phase to the M phase.Recent research has shown that CDC25C could be a pot... BACKGROUND Cell division cyclin 25C(CDC25C)is a protein that plays a critical role in the cell cycle,specifically in the transition from the G2 phase to the M phase.Recent research has shown that CDC25C could be a potential therapeutic target for cancers,particularly for hepatocellular carcinoma(HCC).However,the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood.AIM To explore the impact of CDC25C on cell proliferation and apoptosis,as well as its regulatory mechanisms in HCC development.METHODS Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences(LV-CDC25C shRNA)to knock down CDC25C.Subsequently,a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo.Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays,respectively.The expression of endoplasmic reticulum(ER)stress-related molecules(glucose-regulated protein 78,X-box binding protein-1,and C/EBP homologous protein)was measured in both cells and subcutaneous xenografts using quantitative real-time PCR(qRT-PCR)and western blotting.Additionally,apoptosis was investigated using flow cytometry,qRT-PCR,and western blotting.RESULTS CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction.A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice.CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response,ultimately promoting ER stress-induced apoptosis in HCC cells.CONCLUSION The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway. 展开更多
关键词 Cell division cyclin 25C Hepatocellular carcinoma Endoplasmic reticulum stress PROLIFERATION Apoptosis
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Rural labor migration and farmers’arrangements of rice production systems in Central China:Insight from the intergenerational division of labor
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作者 Xue Shen Quanyu Yang +1 位作者 Rongjun Ao Shengsheng Gong 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期3200-3214,共15页
Rice production is crucial for food security in China,and its relationship with rural labor migration has been studied extensively.Labor migration in rural China has taken new forms in recent years.There has been a di... Rice production is crucial for food security in China,and its relationship with rural labor migration has been studied extensively.Labor migration in rural China has taken new forms in recent years.There has been a discernible trend wherein adult children have started migrating to cities while their elderly parents return to villages to re-engage in on-farm work.The phenomenon has notably shaped the intergenerational division of labor(IDL)within households.However,it remains to be seen how farmers adjust their rice production systems in response to the IDL.The age of 60 years for employment injury insurance is the eligibility threshold for off-farm employment and is used to obtain a source of exogenous variation in the IDL.Based on a representative household survey of 1,752 rice farmers in the Hubei Province of Central China,our fuzzy regression discontinuity analysis reveals that farmers in IDL households are more likely to adopt ratoon rice(RR)than single cropping rice(SR)or double cropping rice(DR).The effect of the IDL varies under different levels of operational scales and specialized agricultural service availability.Further analysis suggests that farmers’arrangements are associated with two potential mechanisms of downward intergenerational transfer.Monetary transfer for urban housing purchases increases RR in IDL households,and time transfer for intergenerational childcare significantly promotes SR in IDL households.This study enhances the understanding of the relationship between rural labor migration and rice production in China,providing a reference for adjusting rice production systems to ensure food security. 展开更多
关键词 labor migration intergenerational division of labor rice production systems fuzzy regression discontinuity Central China
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Structural characteristics and tectonic division of the Zambezi Delta basin in the offshore East Africa:evidences from gravity and seismic data
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作者 Guozhang Fan Wen Li +8 位作者 Liangbo Ding Wanyin Wang Hongping Wang Dingding Wang Lin Li Hao Wang Chaofeng Wang Qingluan Wang Ying Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第4期105-118,共14页
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
关键词 Zambezi Delta basin satellite altimetry gravity anomaly Beira High fault division uplift and depression pattern
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Adjustment of Administrative Divisions and Upgrading of Industrial Structure in Hefei Metropolitan Area:Taking"Partitions of Chaohu"as a Quasi-natural Experiment
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作者 Yumin DING 《Asian Agricultural Research》 2024年第7期19-23,27,共6页
Administrative regions are an important environment for the operation of China's market economy.The relevant economic subjects cannot predict the policy of adjustment of administrative divisions and carry out cons... Administrative regions are an important environment for the operation of China's market economy.The relevant economic subjects cannot predict the policy of adjustment of administrative divisions and carry out conscious migration behavior,adjustment of administrative divisions can be regarded as a quasi-natural experiment.The three cities of Hefei,Wuhu,and Ma'anshan,which are directly related to the adjustment of the administrative division of Chaohu,are taken as the treatment group,and the seven adjacent cities of Lu'an,Huainan,Chuzhou,Bengbu,Anqing,Chizhou,and Tongling are taken as the control group.Differences-in-Differences method and relevant control variables affecting the upgrading of industrial structure are used to test.The test results show that"Partitions of Chaohu"has a significant industrial structure upgrading effect by promoting the optimization of spatial layout,the cross-regional flow of production factors and the effective management of Chaohu Lake Basin.At the same time,the increase of total retail sales of consumer goods,urban fixed assets investment,public utility expenses in science,education,culture and health,and population plays a significant positive role in promoting the upgrading of industrial structure,while foreign direct investment plays a certain inhibition role in the upgrading of industrial structure.In order to meet the ever-developing space demands and enhance the impact on surrounding areas,the Hefei metropolitan area should be driven by technological innovation,strengthen the integration of industrial chains,improve the business environment and transportation network,and continuously promote the upgrading of industrial structure and the formation and development of new productive forces. 展开更多
关键词 Adjustment of administrative divisions Upgrading of industrial structure Hefei metropolitan area Quasi-natural experiment
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Time-sequential color code division multiplexing holographic display with metasurface 被引量:9
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作者 Xin Li Qinmiao Chen +4 位作者 Xue Zhang Ruizhe Zhao Shumin Xiao Yongtian Wang Lingling Huang 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2023年第8期8-16,共9页
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
关键词 metasurface color holography dynamic display code division multiplexing
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Performance of phase-matching quantum key distribution based on wavelength division multiplexing technology 被引量:1
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作者 马海强 韩雁鑫 +1 位作者 窦天琦 李鹏云 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第2期103-107,共5页
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
关键词 quantum key distribution wavelength division multiplexing secret key rate
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Production evolution patterns and development stage division of waterflooding oilfields
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作者 JI Bingyu XU Ting +2 位作者 GAO Xingjun YU Hongmin LIU He 《Petroleum Exploration and Development》 SCIE 2023年第2期433-441,共9页
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
关键词 waterflooding oilfield production evolution development stage division recoverable reserves mature oilfield
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Improved PBFT Consensus Algorithm Based on Node Role Division
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作者 Xiyu Ren Xiangrong Tong Wei Zhang 《Journal of Computer and Communications》 2023年第2期20-38,共19页
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
关键词 Blockchain Consensus Algorithm Practical Byzantine Fault Tolerance Node Role division
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The Epigenetic“Dance”of Cell Divisions
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作者 YAN Fusheng 《Bulletin of the Chinese Academy of Sciences》 2023年第3期164-165,共2页
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
关键词 dividing DANCE division.
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Soil Organic Carbon and Nitrogen Dynamics in Arabica Coffee Agroforestry Systems in the Noun Division, West Cameroon
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作者 Abdel Malik Atoupka Emile Temgoua +2 位作者 Lucie Félicité Temgoua Jean Baurel Atchombou Steve Tassiamba 《Open Journal of Forestry》 2023年第3期262-277,共16页
Agroforestry systems (AFSs) offer viable solutions to climate change because of the below-ground biomass (BGB) that is maintained by the soil. Therefore, spatially explicit estimation of their BGB is crucial to accoun... Agroforestry systems (AFSs) offer viable solutions to climate change because of the below-ground biomass (BGB) that is maintained by the soil. Therefore, spatially explicit estimation of their BGB is crucial to account for emission reduction efforts. A study to assess soil organic carbon (SOC) and nitrogen dynamics in Arabica coffee agroforests was conducted in two subdivisions (Foumbot and Kouoptamo) of the Noun Division in western Cameroon. The methodological approach involved the collection of 150 soil samples taken at different depths: 0 - 10, 10 - 20 and 20 - 30 cm. Depending on the depth, the SOC stock is 27.93 ± 1.13 tC/ha at 10 cm depth, 22.37 ± 1.47 tC/ha at 20 cm and 20.79 ± 0.31 tC/ha at 30 cm. According to the age classes of the Arabica coffee systems (ACA), the C/N ratio in our study area averaged 26.94 ± 13.60 for the (5 - 20) year old systems in Foumbot and 60.64 ± 48.80 for the (20 - 35) year old systems in Kouoptamo. Depending on the depth, at 10 cm this ratio is higher in Kouoptamo than in Foumbot with a maximum value of 57 and 38 respectively for the two subdivisions. In view of the results obtained, it would be important to analyse the types of microorganisms responsible for the decomposition of organic matter which is linked to soil organic carbon. 展开更多
关键词 Agroforestry Systems Coffee Trees Soil Organic Carbon Noun division West Cameroon
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A High Spectral Efficient Frequency-Domain Channel-Estimation Method for the Polarization-Division-Multiplexed CO-OFDM-OQAM System
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作者 Hangyu Zhao Shuo Zhang +2 位作者 Daobin Wang Xiaoxiao Li Lihua Yuan 《Optics and Photonics Journal》 2023年第6期119-132,共14页
Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inhe... Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. . 展开更多
关键词 Orthogonal Frequency division Multiplexing (OFDM-OQAM) Polarization-division-Multiplexing (PDM) Channel Estimation Optical Communication System
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Modeling Daily Average Temperatures in a Coastal Site of Central Africa: An Analysis of Seasonal Divisions
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作者 Jean-Pierre Bell Esther C. Modi-Mbog +1 位作者 Nicodeme Djiedeu Laurent Nana 《Atmospheric and Climate Sciences》 2023年第3期341-352,共12页
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
关键词 Daily Temperature Estimates Earth’s Dynamics Seasonal divisions
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Residual Film Pollution in the Eighth Division of the Xinjiang Production and Construction Corps
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作者 Weijun LI Xingyao ZHANG +3 位作者 Nate KA Xianglin YANG Jianjiang LU Xuyun ZHANG 《Research and Application of Materials Science》 2023年第1期11-16,共6页
This study investigated the residual film content and distribution at different soil depths in the Eighth Division of the Xinjiang Production and Construction Corps.Before spring plowing in 2019,representative fields ... This study investigated the residual film content and distribution at different soil depths in the Eighth Division of the Xinjiang Production and Construction Corps.Before spring plowing in 2019,representative fields in four areas(Anjihai,Shihezi suburbs,Mosuowan and Xiayedi)were selected for residual film collection.The average content of residual film in the Eighth Division was 104 kg/ha.The residual film content in the four areas decreased in the order Anjihai>Shihezi suburbs>Mosuowan>Xiayedi.The average amount of residual film collected from cotton fields was greater than that from corn fields.Residual film content in the cotton field at soil depths of 0~10 and 10~30 cm was higher than that in the corn field,whereas the residual film content at a 30–50 cm soil depth in the corn field was higher than that in the cotton field.The results showed that farmers do not consider the long-term benefits,the high cost and short time of recycling,and the easy recycling of surface residual film.The shallow that the higher content of residual film,the less water in the soil of cotton.The same time,the results showed that the quantity of residual film in cotton field had greater influence on cotton quality. 展开更多
关键词 Eighth division Residual film POLLUTION Present situation PROBLEMS
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基于Division Mockup的卫星虚拟装配系统研究与开发 被引量:7
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作者 夏平均 姚英学 +1 位作者 孙刚 易旺民 《中国机械工程》 EI CAS CSCD 北大核心 2008年第19期2340-2343,共4页
以虚拟装配软件Division Mockup为平台,提出了卫星虚拟装配系统的体系结构,并在Division Mockup软件下完成了卫星产品的装配过程规划。针对Division Mockup只偏重于装配过程图形仿真的特点,开发了后端的卫星装配工艺生成系统,并通过数... 以虚拟装配软件Division Mockup为平台,提出了卫星虚拟装配系统的体系结构,并在Division Mockup软件下完成了卫星产品的装配过程规划。针对Division Mockup只偏重于装配过程图形仿真的特点,开发了后端的卫星装配工艺生成系统,并通过数据接口实现了和Division Mockup的集成,从而完成工序工步规划、工艺文档生成、装配现场示教等功能。最后给出了系统的应用实例。 展开更多
关键词 虚拟装配 工艺规划 division MOCKUP 卫星
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基于Division Mockup装配仿真的实现方法 被引量:6
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作者 邵晓东 聂力 《机械设计与制造》 北大核心 2007年第3期54-56,共3页
虚拟装配技术是CAD领域研究的关键技术之一。随着计算机软硬件技术的发展,虚拟装配在个人计算机上也能够实现。本文以大型面天线为例,介绍了在Division Mockup的软件环境下进行虚拟装配,并进行相应的干涉检验,截面分析等。
关键词 虚拟装配 division MOCKUP 干涉检验 模型转换
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Effects of Tobacco Plastid Division Genes NtFtsZ1 and NtFtsZ2 on the Division and Morphology of Chloroplasts 被引量:4
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作者 王东 孔冬冬 +3 位作者 鞠传丽 胡勇 何奕昆 孙敬三 《Acta Botanica Sinica》 CSCD 2002年第7期838-844,共7页
As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division... As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant. 展开更多
关键词 Nicotiana tabacum ftsZ gene plastid division plastid morphology plastoskeleton
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基于Division Mockup的分油机虚拟装配系统的研究 被引量:1
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作者 原彬 路慧彪 邹玉堂 《现代制造工程》 CSCD 北大核心 2013年第1期25-27,58,共4页
以Division Mockup软件为平台,进行了船用分油机的虚拟装配过程仿真。给出了虚拟装配系统的体系结构,介绍了不同CAD系统与Division Mockup软件之间的格式转换、交互式装配过程的进行,以及工艺文档生成等关键技术的研究。最终形成可进行... 以Division Mockup软件为平台,进行了船用分油机的虚拟装配过程仿真。给出了虚拟装配系统的体系结构,介绍了不同CAD系统与Division Mockup软件之间的格式转换、交互式装配过程的进行,以及工艺文档生成等关键技术的研究。最终形成可进行装配验证和示教功能的分油机系统。 展开更多
关键词 虚拟装配 division Mockup软件 分油机
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The Division Method of Winter Wheat Drought Risk Zones in Hebei-Shandong-Henan under Irrigation Conditions 被引量:4
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作者 张文宗 张超 +1 位作者 赵春雷 刘晶淼 《Agricultural Science & Technology》 CAS 2010年第3期123-128,共6页
The average rainfall in whole growth period of winter wheat to plus or minus several times of sample variance was used to define different grades of drought.The reduction rate of production in meteorological which was... The average rainfall in whole growth period of winter wheat to plus or minus several times of sample variance was used to define different grades of drought.The reduction rate of production in meteorological which was equal to or greater than the rate of 3% was taken as standards to define wheat drought disaster years.The average reduction ratio of production in the wheat drought years in Hebei-Shandong-Henan was calculated.The frequency distribution rule of wheat in different drought disaster strength of winter wheat in Hebei-Shandong-Henan was analyzed.According to the conception and calculation method of drought disaster risk index of winter wheat,the regional distribution law of drought disaster risk index of winter wheat was analyzed.The division technical methods of winter wheat drought disaster risk zones in Hebei-Shandong-Henan under the irrigated conditions were put forward.Taking the average reduction rate of production in drought years,drought disaster risk index and precipitation of winter wheat in growth periods as indices,using the statistical analysis and overlay function of GIS,the production reduction risk of winter wheat caused by drought disaster in winter wheat zones of Hebei-Shandong-Henan was divided and evaluated.The risk evaluation of production reduction of winter wheat in different risk zones under different climate conditions was realized.The disaster prevention and mitigation measures of winter wheat drought were given. 展开更多
关键词 Hebei-Shandong-Henan Winter wheat drought Risk assessment and division
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