Simulation of the Accumulation Process of Biogenic Gas Hydrates in the Shenhu Area of Northern South China Sea

Previous work has largely discussed the relations between sediment structures and accumulation of gas hydrates in the Shenhu area of South China Sea, but has not documented why the gas hydrates occurred at the seafloor topographic highs. Many gas hydrate exploration examples abroad also indicate that the saturation of gas hydrates was higher at seafloor topographic highs. This work aims to understand why gas hydrates accumulated at topographic highs and why their saturation is higher.

Analysis on the Heavy Snow Weather Process in Benxi Area

[Objective] The aim was to study the formation and development of a heavy snow in Benxi area. [Method] Based on conventional meteorological data, the formation and development of a heavy snow in Benxi area from December 4th to 5th in 2009 were analyzed from the aspects of weather situation evolution and physical quantity field feature. [Result] The heavy snow was caused by upper trough and North China cyclone. In this process, there was upper level divergence and lower level convergence over Benxi area, and it was warm at low attitude and cold at high attitude; southwest jet at low attitude transported water vapor from Bohai Sea to eastern Liaoning, which provided good water vapor condition for snow, but it didn’t reach heavy snow due to inadequate ascending force. The development of Ural Mountains high ridge played an important role in the snow process and the strengthened high ridge moving northward was beneficial to the southward movement of cold air and deepening of upper trough. Analysis on physical quantity field could provide reference for predicting beginning and ending time and strength of heavy snow. [Conclusion] The study could provide basis for the forecast of heavy snow.

Evaluation of Rainwater Harvesting Methods and Structures Using Analytical Hierarchy Process for a Large Scale Industrial Area

In India, with ever increasing population and stress on natural resources, especially water, rejuvenation of rainwater harvesting (RWH) technique which was forgotten over the days is becoming very essential. Large number of RWH methods that are available in the literature are demand specific and site specific, since RWH system depends on the topography, land use, land cover, rainfall and demand pattern. Thus for each and every case, a detailed evaluation of RWH structures is required for implementation, including the analy-sis of hydrology, topography and other aspects like site availability and economics, however a common methodology could be evolved. The present study was aimed at evaluation of various RWH techniques in order to identify the most appropriate technique suitable for a large scale industrial area to meet its daily wa-ter demand. An attempt is made to determine the volume of water to be stored using mass balance method, Ripple diagram method, analytical method, and sequent peak algorithm method. Based on various satisfying criteria, analytical hierarchy process (AHP) is employed to determine the most appropriate type of RWH method and required number of RWH structures in the study area. If economy alone is considered along with hydrological and site specific parameters, recharging the aquifer has resulted as a better choice. However other criteria namely risk, satisfaction in obtaining required volume of water for immediate utilization etc. has resulted in opting for concrete storage structures method. From the results it is found that AHP, if used with all possible criteria can result in a better tool for evaluation of RWH methods and structures. This RWH structures not only meets the demand but saves transportation cost of water and reduces the dependability of the industry on irrigation reservoir. Besides monetary benefits it is hoped that the micro environment inside the industry will improve due to the cooling effect of the stored water.

A Study on Law of Change of Real Contact Area of Friction during Transition Process

Mechanism of frictional vibration and the difference of kinctic-static friction is an open question. Research shows that the change of real area of contact during transition process of friction results in the phenomena mentioned above. In substance, the F-Vr, descent and F-T ascent characters are caused by A-Vr, and A-T characters respectively. Based on ultrasonic experiment the mechanism of the phenomena is explained and the frictional formulas using the parameter-real area of contact are given in this article.

Study on Winter Operation Process of the Surface Flow Constructed Wetland in Tianjin Area

[Objective] The research aimed to study winter operation process of the surface flow constructed wetland in ＂rianjin area. [Method] In view of climate characteristics in Tianjin, by the way of running under the ice, winter operation experiment of the surface flow constructed wetland in Tianjin was conducted, with the expectation to get some useful process parameters to run such systems in North China in winter. [ Result] Although purification effect of the sewage by surface flow constructed wetland in winter was worse than that in other seasons （ average reduction of about 20%）, surface flow constructed wetland running under the ice was feasible in Tianjin area. When surface flow constructed wetland in North China ran under ice in winter, it was suggested that the outlet must be located in a low position to prevent to be completely frozen, and running water depth should not be less than 50 -60 cm. The hydraulic load could be raised on the basis of reflux, and hydraulic retention time should maintain less than 4 d to keep water-soil interface not freezing. Inlet water depth should be increased as much as possible to improve temperature in the system. V Conclusion1 The research could provide reference for promotion and application of the surface flow constructed wetland in North China.

Hydrocarbon Accumulation Process in the Marine Strata in Jianghan Plain Area, Middle China

Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, can be identified with each epoch. The geology, stratigraphy, drilling, oil testing and other basic data as well as the measured inclusion and strontium isotope data in the study area are used in the analysis of the formation and evolution process of marine petroliferous reservoirs in the Jianghan Plain area. This study aims to provide a scientific basis for the further exploration of hydrocarbons in the Jianghan Plain and reduce the risks by analyzing the key factors for hydrocarbon accumulation in the marine strata. Our findings show that in the Lower Palaeozoic hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the early period of the Early Yanshanian, and the hydrocarbon reservoir was destroyed in the middle-late period of the Early Yanshanian. In the Lower Triassic-Carboniferous hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the Early Yanshanian, and the hydrocarbon reservoir suffered destruction from the Late Yanshanian to the Early Himalayanian. The preservation conditions of the marine strata in the Jianghan Plain area have been improved since the Late Himalayanian. However, because all source beds have missed the oil/gas generation fastigium and lost the capacity to generate secondary hydrocarbon, no reaccumulation of hydrocarbons can be detected in the study area＇s marine strata. No industrially exploitable oil/gas reservoir has been discovered in the marine strata of Jianghan Plain area since exploration began in 1958. This study confirms that petroliferous reservoirs in the marine strata have been completely destroyed, and that poor preservation conditions are the primary factor leading to unsuccessful hydrocarbon exploration. It is safely concluded that hydrocarbon exploration in the marine strata of the study area is quite risky.

Modeling of Deposition Process of Particulate Organic Matter (POM) with Sand on Vegetated Area in a River

The transport and deposition of particulate organic matter (POM) in river streams has recently received much attention as one of important ecological processes in rivers. We focused on interacted behaviors of sand particles in bed load and POM in vegetated area on sand bars. The purpose of this study is to clarify the characteristics of deposition of POM with bed load on sandbars with the riparian vegetation. A basic experiment on POM transport and deposition with vegetation is conducted in a laboratory flume. It demonstrates that several issues still remain to be future investigated. In particular, the shear due to the bed roughness in the vegetated area and the transport and deposition process of sand particles and POM are required to be described by the proper modeling which will be introduced into a simulation model of various fluvial processes. The main results of this study are that ripples are formed by bed load in riparian vegetation and POM deposition is promoted by ripple behavior. Based on these results, the POM deposition with ripples in vegetated area is described by a conceptual model which will affect various aspects in ecosystem management based on fluvial processes.

多段AO+MBR工艺在寒区污水厂提标改造的应用

采用多段AO+MBR工艺对中国北方寒区城市某污水厂出水TN波动大、尾水外排容量低等问题进行提标改造。多段AO可以实现TN的高效去除,而MBR+臭氧催化氧化则可以实现COD、NH_(3)-N的有效控制,从而达到稳定出水的目的。提标改造后实际运行数据表明:出水COD和NH_(3)-N、TN、TP、SS检测均值分别为26.60 mg/L和0.29、7.59、0.38、5.32 mg/L,均达到《城镇污水处理厂污染物排放标准(GB 18918-2002)》中的一级A标准,其中NH_(3)-N达到《地表水环境质量标准》(GB 3838-2002)中的Ⅲ类水标准(ρ(NH_(3)-N)≤1.0 mg/L),TN稳定优于《城镇污水处理厂污染物排放标准(GB 18918-2002)》中的一级A标准(ρ(TN)≤15 mg/L)。

城镇污水处理工程研究与环境效益分析

为有效解决城镇污水排放问题,减少对自然水体的污染,改善城镇环境质量,开展了污水处理工程的深入研究,并对工程实施后的环境效益作出了评估分析。建立时间序列分析模型,实现城镇污水排放量预测。确定污水控制目标,实现污水排放量的减少、水质改善以及环境保护。通过污水处理技术选型,以实现城镇水污染的有效控制。最后,开展污水处理工程规划,确保污水处理工程中的各功能区合理划分、管道布置顺畅、构筑物位置合理。通过环境效益分析可知,经过处理后,各关键水质指标的浓度均明显降低,有效减轻了城镇水体污染。

大面积混凝土张拉工序验收合格率提升策略研究

大面积混凝土张拉工序是混凝土施工中一种常见且关键的技术,通过预应力钢筋的张拉达到增强混凝土结构性能的目的。该工序的验收合格率直接影响到工程质量和安全性。在大面积混凝土工程中,由于施工复杂性和环境变量的多样性,因此保证张拉工序的合格率非常重要。文章首先明确了张拉工序验收的基本要求与标准规范;其次系统地分析了影响验收合格率的主要因素,包括材料质量和施工环境;再次提出了一系列实用的提升方法,如加强施工前的准备、改进施工过程中的质量控制,以及施工后的详细验收;最后通过具体案例的内容与数据分析,展示了这些方法的实际效果和应用价值。

化工储罐区的管道工艺与配管工艺研究

针对某化工企业储罐区改造项目进行设计,明确相关安全要点,在此基础上落实管道施工与配管工艺。施工部分根据储罐区实际需求选择合适材料,并通过流体动力学分析控制压力损失与热膨胀补偿,根据介质特性与环境条件进行防腐保护。配管工艺部分,根据管道应力、介质条件科学选择泵机设计运维参数,有效提高运行质量。

Analysis of Coverage and Area Spectrum Efficiency of UDN with Inter-Tier Dependence

Stochastic geometry is widely employed to model cellular network. But in most existing works, base stations(BSs) are modelled following a homogeneous Poisson point process(PPP) for one-tier network, or several independent homogeneous PPP for multi-tier network, which ignore the dependence among BSs. In this paper, a three-tier UDN(Ultra dense network) with Macrocell BSs(MBS) for basic coverage, Picocell BSs(PBSs) deployed outside the coverage area of MBSs for compensating coverage holes, and Femtocell BSs(FBSs) surrounding MBSs for capacity improvement modelled by point process with inter-tier dependence is proposed. The tier association probability, the coverage probability and area spectrum efficiency(ASE) are derived. Simulation results validate our derivation, and results show that the proposed network model has 25%-45% performance gain in ASE.

Process and mechanism of arable land change in Hebei Province during the past 50 years

Hebei Province is one of the regions with most densely population, fastest economic growth and most intensive land use in China. The contradiction of land shortage sharpened by high-speed economic development with population growth has become a serious problem, which has restricted regional sustainable development.This paper revealed the basic process, regional differences of change and the gravity center of arable land area according to the long-series statistical data of arable land during the past 50 years. On the basis of the above mentioned, the major driving forces that influence the changes of the arable land are discussed. The research results indicate that there is a trend of obvious fluctuating decrease in arable land area during the last 50 years. The changes of arable land area undergo the process from increase to sharp decrease to gently decrease. The regional disparity of change in arable land area is very notable and the gravity center of arable land area moves to the northeast 49.22 km. Regarding the decrease in arable land, the direct driving forces include adjustments of agricultural structure and reclamation, and indirect driving forces include advance in technology, economic interest and population growth etc.

A review of stand basal area growth models

Growth and yield modeling has a long history in forestry. The methods of measuring the growth of stand basal area have evolved from those developed in the U.S.A. and Germany during the last century. Stand basal area modeling has progressed rapidly since the first widely used model was published by the U.S. Forest Service. Over the years, a variety of models have been developed for predicting the growth and yield of uneven/even-aged stands using stand-level approaches. The modeling methodology has not only moved from an empirical approach to a more ecological process-based approach but also accommodated a variety of techniques such as： 1） simultaneous equation methods, 2） difference models, 3） artificial neural network techniques, 4） linear/nonlinear regression models, and 5） matrix models. Empirical models using statistical methods were developed to reproduce accurately and precisely field observations. In contrast, process models have a shorter history, developed originally as research and education tools with the aim of increasing the understanding of cause and effect relationships. Empirical and process models can be married into hybrid models in which the shortcomings of both component approaches can, to some extent, be overcome. Algebraic difference forms of stand basal area models which consist of stand age, stand density and site quality can fully describe stand growth dynamics. This paper reviews the current literature regarding stand basal area models, discusses the basic types of models and their merits and outlines recent progress in modeling growth and dynamics of stand basal area. Future trends involving algebraic difference forms, good fitting variables and model types into stand basal area modeling strategies are discussed.

基于高速公路服务区增设出入口重要度的综合评价模型

高速公路服务区增设出入口(即服务区“开口子”)是国内近年来高速公路新增互通的新模式,但如何界定服务区是否应增设出入口的相关研究尚处于起步阶段,标准各异。为保障服务区增设出入口的科学合理,构建高速公路服务区增设出入口重要度综合评价模型,利用层次分析法确定指标权重,并选取154个服务区进行案例分析。结果表明,运用所提出的模型方法判定区域内各服务区增设出入口的重要度具备科学合理性,可为决策者提供一定的参考价值。

Study on Cultivated Land Resource Situation and Its Macro-Driving Forces in Yantai Area

According to the statistics of cultivated land in Yantai area during the Reform and Opening-up over the past 20 years and with the detailed survey and changing data of land use during the recent live years, this paper reveals the basic characteristics of the resource utilization, the basic process of the changes, regional differences, and current direction of cultivated land In addition, this paper makes a preliminary research on the major driving factors and the influence mechanism for the changes in the cultivated land area. and reaches the following conclasions： （1） There was a trend of obvious fluctuant decrease in cultivated laud area during the past 20 years. The changes of cultivated land have undergone the process - slow decrease,steep decrease, slow decrease. And there were three peak periods of cultivated land loss around 1985. 1987-1996 and 1991-1993 respectively （2） The decreased cultivated land was mainly converted into land for industry and mining, residential area. and all kinds of traffic and orchards. The increase of cultivated land mainly came from exploitation and land and arrangement and reclamation of industry and mining land （3） The economic development. population growth and policy are the dominant macro-driving factors for the decrease of cultivated land area in Yantai. The obvious sudden changes during the change process of cultivated land acreage are relevant to the national macro.policies background The rapid decrease of cnltivated land area is synchronous with the overheated economic growth resulting from the direct investment in fixed assets. Spatial distribution of the decrease in cultivated land is congruous with the differences in speed and the scale of economic growth between the different regions of Yantai area. Furthermore. the decrease in cultivated land caused by population increase cannot be ignored.

Study of One Rainstorm Being Affected by Two Weather Systems in Jinzhou Area

[Objective] The aim was to study one rainstorm process being affected by two weather system. [Method] Influenced by high trough and Mongolia cold front, high latitude trough and subtropical high shear, rainstorm occurred in Jinzhou from October 19 to 22 in 2010. In order to make the analysis clear, there were two precipitation stages. Considering precipitation, weather situation, satellite image and numerical forecast, the rainstorm process was discussed. [Result] There were two raining stages during this precipitation. The first stage was affected by high altitude trough and ground Mongolia cold front, and the last stage was influenced by high altitude trough and subtropical high shear;the high latitude air, low latitude shear,low air torrent,subtropical high and their mutual coupling effect were the main influencing system and cause for this rainstorm. Satellite image suggested that there was convective cloud developing,weakening, disappearing and regenerating around the convective cloud of water vapor passage, showing distinct train operation state. The strengthening and weakening cloud image fitted the real precipitation. Numerical forecast precisely predicted the upper air and ground situation of the generation of rainstorm, especially the report of the east-retreating and south-falling trend of subtropical high;European center forecast fitted reality. There was certain error in predicting T639. Precipitation forecast was fine. [Conclusion] The study provided basis for the meteorological service work in future.

基于Process Simulate的机器人运动程序开发及应用

针对目前汽车行业车身车间越来越高的自动化程度和日益复杂的车型更新,使用Tecnomatix软件进行虚拟调试,把前期设计数模导入Process Simulate模块,进行运动仿真和碰撞模拟测试,提前发现设计缺陷,并与机器人厂家联合开发运动和工艺模块,与上位PLC进行逻辑处理,与下位应用设备进行标准化模块处理及数据通信,提前在虚拟化环境中进行验证,最终输出机器人运动和安全程序,提高了机器人程序的质量并且能够大大减少现场调试时间。

Evaluation of suitability area by ground source heat pump system in Baotou plain

According to the elements of hydrogeological conditions,lithology,stratigraphic thermal physical parameters,construction technology and economic rational elements,the evaluation system of ground source heat pump( GSHP) were established in Baotou plain. The factor weights were determined by using analytic hierarchy process,and the comprehensive element method was selected to evaluate the region suitability of GSHP system. The results show that the suitable area is 559. 63 km2 for utilizing GSHP in the studied area,accounting for 62. 58% of the total area; while the unsuitable area is 334. 60 km2,accounting for37.42%. The evaluating results can provide not only a scientific basis for development and utilization rationally of shallow geothermal heat in Baotou,but also offer an important reference to the other areas.

喀什地区复播小米的品质评价

为探究喀什地区复播的不同品种谷子小米营养品质的差异,试验以不同来源的4个谷子品种作为分析对象,对小米中的9种矿质元素Na、Mg、K、Ca、Mn、Fe、Cu、Zn、Se含量进行检测,并对其4种营养指标脂肪酸、粗蛋白、粗脂肪、淀粉含量进行检测分析,最后对其生产加工方向进行综合预测。结果表明,各元素含量在不同品种谷子间差异显著,其中Na含量为8.24~31.18μg/g,Mg含量为869.42~1 580.23μg/g,K含量为2 326.80~5 033.01μg/g,Ca含量为110.64~395.88μg/g,Mn含量为11.39~21.11μg/g,Fe含量为15.94~57.46μg/g,Cu含量为0~7.51μg/g,Zn含量为15.10~35.94μg/g,Se含量为0.070 7~0.176 8μg/g。小米矿质元素总量范围为3 365.10~6 874.92μg/g,变异系数为25.95%;不饱和脂肪酸含量丰富而且在不同品种间差异显著;粗蛋白、粗脂肪、淀粉的含量范围分别是12.9%~13.69%、4.54%~6.02%、68.8%~76.76%,变异系数分别为5.00%,11.42%和4.91%。不同品种谷子小米直链淀粉含量差异不大,对其糊化温度与胶稠度分析后发现,陇谷29易蒸煮、适口性更好。不同品种谷子小米的营养品质存在差异性,陇谷29总体表现优异,晋谷21次之,二者均可作为企业生产的储备品种。