农村进城务工女性定居目标和城市融入过程分析——基于四川省成都市务工女性个案调研

农村进城务工女性作为流动大军中的另一个中坚力量,为城市的发展和进步做出了巨大贡献。随着城市化进程脚步的加快,在城市务工的部分农村女性也加入了向城市迁移的行列,由过去农村女性多数是以婚嫁、随迁等形式被动地向城市迁移逐步演变为现在以务工、留城的主动迁移。在实现定居目标的过程中,受就业现状、社会交往、文化观念、自我定位、婚恋状况等因素的影响,农村务工女性呈现出与务工男性不同的境况。透过就业现状、社会交往、文化观念、自我定位、婚恋状况的变化来分析务工女性定居目标和城市融入过程,可以为改善务工女性的生存和发展环境提供帮助。

Moving Behavior of an Object in Gas-Solid Fluidized Beds

The settling behavior of coarse particles in a gas-solid fluidized bed was experimentally studied by using magnetic tracer. It is well known that the calculation of terminal velocity is of interest in dense medium separation. However, this problem has not been completely solved up to now. In this work, the terminal velocity of an object mov-ing in a gas-solid fluidized bed was experimentally measured and theoretically calculated. The experimental results in-dicated that the plastic viscosity and yield stress of the bed increase as the size of fluidized particles increases, but it varies little when some coarser particles are mixed with the fluidized particles. The resistance to a rising object was an order magnitude greater than that to a settling object. The efficient buoyancy on a flaky object, which lies flatly on the gas distributor, was much less than that calculated by the Archimedes principle. The object does not always rise or set-tle with minimal projective area owing to radial motion of the fluidized particles. But in the lower part of the bed, the bar-shaped objects were likely with minimal projective area rising or settling.

Sedimentary facies characteristics and organic matter enrichment mechanism of lower Cambrian Niutitang Formation in South China

The purpose of this study was to examine the sedimentary facies characteristics of lower Cambrian Niutitang Formation(∈1n)in South China,to reveal the mechanism of organic matter enrichment,and to guide exploration of shale gas.Macro investigation and experimental analyses were used to assess the lithology in detail,total organic matter mass fraction w(TOC),mineral composition,and trace element characteristics of∈1n.The influencing factors of organic matter enrichment were discussed extensively,and a sedimentary facies mode was suggested.In the early stage of∈1n,the locations of Well E’yangye 1,Well Ciye 1,Well Changye 1,and Well Anye 1 respectively develop,platform inner sag,outer shelf,Jiangnan slope belt,and South China detention basin.In the late stage of∈1n,the sedimentary facies evolve with decreasing sea level.The study area presents a complete three-step basin in the Early Cambrian.In the early stage of∈1n,the first step is the Yangtze carbonate platform,the second step is the outer shelf and slope,and the third step is the deep-water basin.From the Yangtze carbonate platform to the deep-water basin,w(TOC)and the mass fraction of quartz gradually increase,the mass fraction of carbonate mineral decreases,and the mass fraction of clay mineral is higher in the second step.The sea level fluctuation results in a higher w(TOC)vertically in the lower∈1n shale,and the paleogeographic(provenance)conditions lead to better horizontal development of organic matter in the outer shelf,slope and detention basin.Trace elements are abundant in the lower∈1n,and w(TOC)is correlated positively with many trace elements.In the outer shelf,slope,and adjacent areas,hydrothermal activity and upwelling current bring nutrient-rich material and promote organic matter enrichment under a strong reducing condition.Deep-shelf,slope and deep-water basin are the best facies for the formation and preservation of organic matter,especially deep-water basin facies.It remains necessary to strengthen the exploration of shale gas in the deep-water basin of∈1n in central Hunan,China.

A robust system for real-time pedestrian detection and tracking

A real-time pedestrian detection and tracking system using a single video camera was developed to monitor pedestrians. This system contained six modules: video flow capture, pre-processing, movement detection, shadow removal, tracking, and object classification. The Gaussian mixture model was utilized to extract the moving object from an image sequence segmented by the mean-shift technique in the pre-processing module. Shadow removal was used to alleviate the negative impact of the shadow to the detected objects. A model-free method was adopted to identify pedestrians. The maximum and minimum integration methods were developed to integrate multiple cues into the mean-shift algorithm and the initial tracking iteration with the competent integrated probability distribution map for object tracking. A simple but effective algorithm was proposed to handle full occlusion cases. The system was tested using real traffic videos from different sites. The results of the test confirm that the system is reliable and has an overall accuracy of over 85%.

基于目标流动性比率的商业银行流动性管理研究

本文从银行的目标比率视角出发,探究中国商业银行的流动性管理效率和模式,以及不同流动性充裕程度和不同所有制银行的异质性。研究发现,中国商业银行会围绕目标流动性比率调整流动性结构;中国商业银行倾向于减少短期和易受冲击的负债,增加长期稳定的负债和资产;不同所有制银行的管理模式并不相同,主要是由于市场竞争力、融资渠道、融资成本和投资多元化程度存在差异。上述结果表明,中国商业银行的流动性管理效率有所提升,但还存在融资和投资渠道单一、过度依赖传统流动性工具等问题。本研究为探讨中国微观银行行为提供了新的证据和视角,为当下中国流动性监管改革提供政策建议。

Cytarabine and paclitaxel exhibit different cell-cycle specificities in different cell growing status

Objective： To investigate the cell-cycle specificities of cytarabine and paclitaxel in different growing status of target cell. Methods： Using flow cytometry, we tested the cell-cycle specificities of cytarabine and paclitaxel on acute lymphocyte leukemia cell line Molt-4 in different growing status and on clinical acute lymphocyte leukemia specimens in vitro as well as in leukemia patients in vivo. Results： Cytarabine induced S phase specific cebcyde blockage and apoptosis in exponentially growing Molt-4, but showed G0/G1 phase specificity in high-density cultured Molt-4 and in clinical specimens. Paclitaxel induced G2/M phase specific cell-cycle blockage and apoptosis in exponential Molt-4, but showed G0/G1 phase specificity in high-density cultured Molt-4 and S phase specificity in clinical specimens. In the first day of clinical chemotherapy, cytarabine induced G0/G1 with a little S phase apoptosis in leukemia cells of acute lymphocyte leukemia patient in vivo. Cytarabine plus paclitaxel together had almost the same effect in the second day. Conclusion： The cell-cycle effects of cytarabine and paditaxel were different in different target cell growing status. It should be noted that the in vivo effect of these agents may be different from people usually anticipated during clinical chemotherapy. So the combined chemotherapeutic regimens may need to be redesigned.

股票市场流动性风险计量模型研究

本文通过对流动性风险本质属性的探讨,提出了目标流动性的概念,建立了两个新的流动性风险计量模型模型,一是用流动性不足的均值测度流动性风险模型;一是包含流动性不足及其波动性的流动性风险综合测度模型。并以上海证券交易所上市的148只A股为样本进行实证检验,结果表明该模型能够科学计量股票流动性风险。

Flow field optimization and design for a Spallation Neutron Source target cooling system

Cooling water is an important part in a Spallation Neutron Source target cooling system, but the unstable vortexes at the exits of the slits between every two tungsten target slices have a negative impact on the stable running of the target system. We apply the field synergy principle for fluid flow to obtain the optimal flow field, which has a uniform velocity distribution without eddy, and then, optimize the geometrical structure of the cooling water flow channel based on the optimal flow field. The results show that when the cooling water flows in the optimized channel, the eddy sizes decrease, the time fluctuations of velocity and pressure almost vanish, and the volume flow rates of the cooling water in each parallel slit are uniform. Therefore, it effectively improves the running stability of the target system with the premise of satisfying the target heat load.

Internal flow structure,fault detection,and performance optimization of centrifugal pumps

This review mainly summarizes the latest developments in the internal flow field and external characteristics of centrifugal pumps.In particular,the latest findings of centrifugal pumps focused on turbulence and cavitation models,flow visualization methods,and fault detection based on noise and vibration.The external characteristics,cavitation,and vibration of the centrifugal pump were extensively discussed.In addition,advanced multi-objective optimization methods for improving impeller’s efficiency and reducing net positive suction head(NPSH)were briefed.Although some progress was made in this field,there remain many unsolved problems,such as monitoring and modeling of cavitation,rotational stall phenomenon,and discrepancies between simulation and measurement.In the future,researchers are encouraged to employ multi-dimensional flow visualization technologies and high-performance computing facilities to advance existing understandings on these issues and create new research directions.