600 MW燃煤发电机组SCR分区动态喷氨改造

一600MW燃煤发电机组SCR烟气脱硝系统存在磨损严重、氨耗量大、氨逃逸高、空预器堵塞等问题,优化改造提升需求迫切。通过流场和分区动态喷氨改造,系统总体性能明显提升。催化剂入口截面气流速度分布相对标准偏差降低至8.71%,NH3质量分数分布相对标准偏差降低至1.92%,满足行业规范要求;平均喷氨量从160kg/h减小至105kg/h,最大喷氨量从280kg/h减小至130kg/h,喷氨波动明显降低,改造效果明显。

嫩江干流富裕县段河道砂石供需分析

嫩江干流富裕县段河道砂石储量丰富,其品质优良且储量巨大,是黑龙江省最为重要的砂石供应基地。富裕县周边的经济社会发展日新月异,对砂石的需求量也随之大幅增长。根据齐齐哈尔市和大庆市近几年的水泥使用情况,并按照混凝土生产中水泥与砂石的配合比1∶2.1进行估算,富裕县周边的砂石需求量预计为每年872万t/年。文章进行了初步的河道砂石供需分析,并提出相关建议。

中国耕地整理潜力测算分析(英文)

耕地整理是增加耕地面积的重要途径,该研究提出新形势下中国耕地整理潜力的测算方法,并以2008年中国土地利用变更调查数据和中国农用地分等数据为基础,结合耕地整理典型项目区的资料等,以县为单位,对中国的耕地整理数量潜力和质量潜力进行了测算。结果表明,中国的耕地整理的数量和质量潜力巨大,耕地整理的数量潜力和质量潜力呈现较一致的集中分布特点。数量潜力较高的县主要分布在东北地区的黑龙江省和吉林省,东部地区的河南、安徽、湖北省,西南地区的四川、贵州、云南省和西北地区的新疆地区;质量潜力较高的县主要分布在东北地区的黑龙江省,西北地区的新疆和内蒙古和宁夏地区,其次是东部的山东省、安徽省和中部的湖北省、湖南省,西南地区的贵州、四川、云南省的潜力也较高。研究结果对掌握中国耕地整理潜力分布特点和确定中国的耕地整理重点区有指导作用,并可为编制中国土地综合整治规划提供数据基础。

摩擦材料从轻微磨损向严重磨损转变的机理研究综述

摩擦材料的工作状态分为轻微磨损和严重磨损。轻微磨损状态下摩擦副具有低且平稳的摩擦因数和磨损率,可以保证机械设备的安全工作条件;严重磨损状态下摩擦副具有较高的摩擦因数和磨损率,摩擦因数变动范围大,摩擦副发生咬合甚至失效。研究摩擦材料从轻微磨损向严重磨损的内在机理和影响因素对实际的工程应用具有现实的指导意义。概括了近几十年来研究轻微磨损向严重磨损转变的文献资料,从温度、滑动速度、载荷、对偶硬度等有关影响因素以及磨损机理转变图、理论研究等方面进行总结和评述以及分析,研究结果表明,尽管影响材料从轻微磨损向严重磨损转变的因素较多,但主要因素是在材料摩擦过程中只要强度达到相应温度下的极限就会发生从轻微磨损向严重磨损的转变。

固溶和工作温度对TC21钛合金动态压缩性能和绝热剪切敏感性的影响

利用Hopkinson压杆试验系统,在高应变率1500 s-1和不同温度(25~400℃)条件下,研究了固溶温度对TC21钛合金动态抗压性能及绝热剪切敏感性的影响。结果表明,随着固溶温度的升高,TC21合金的高温动态流变应力增大,塑性应变减小,绝热敏感性增大,剪切带宽度减小。分析表明,引起这种变化的主要原因是随固溶温度的升高,合金基体组织中α相的总面积和片层宽度减小。随着工作温度的升高,TC21合金的动态流变应力降低,绝热敏感性增大,剪切带宽度增加。

Land-use Change and Socio-economic Driving Forces of Rural Settlement in China from 1996 to 2005

While urbanization has accelerated, the rural population in China has started decreasing in recent years. However, the expansion of rural settlement has not been sufficiently curbed. The questions of why this has happened and who has driven the land-use change(LUC) of rural settlement in China have aroused great interests among researchers. In this paper, it is suggested that population is not always a positive driving force for the LUC of rural settlement in China. Furthermore, socio-economic driving forces other than urbanization, population and industrialization are analyzed. On a national scale, the major driving forces are the per-capita rural housing area and the cultivated land area. On a regional scale, the main driving forces in the eastern China are the house-building capacity of rural households and the per-capita rural housing area; while in the central China, the main driving forces are rural housing investment, the proportion of primary industry employees in the rural working population, and the cultivated land area. For the western China, the main driving forces are rural register population and cultivated land area.

Evaluation for Use Efficiency of Agricultural Resources in Grain Production:A Case Study of Changshu,Taihe and Ansai in China

This paper aims to establish an index system for evaluation of agricultural resources use efficiency(ARUE) in grain production and discuss the causes of low efficiency and high consumption of agricultural resources in Changshu of Jiangsu Province,Taihe of Jiangxi Province and Ansai of Shaanxi Province in China by analyzing the data about meteorology,soil,water consumption and grain production. Agro-ecological Zone(AEZ) method was adopted to calculate the potential productivity,and synthetically multivariate equation was used to evaluate the ARUE of study areas. This paper can be concluded as:1) the agricultural resources in grain production can be classified into five categories,i.e.,climatic resources,water resources,land resources,biological resources and assistant resources,and 15 indexes were selected to evaluate their use efficiency in grain production;2) the values of ARUE in grain production are 0.5868,0.6368 and 0.5390 respectively in Changshu,Taihe and Ansai;and 3) Changshu ranks the highest among the three study areas in terms of the use efficiency of climatic resources and biological resources(evaluation values are 0.0277 and 0.1530) ,but Taihe tops the three in terms of the use efficiency of water resources,land resources and assistant resources(evaluation values are 0.0502,0.2945 and 0.1379 respectively) . However,the ARUE remains always low in Ansai for all the resources. The inefficiencies are caused by poor grain revenue in Changshu,deficient agriculture investments in Taihe and unfavorable natural conditions in Ansai.

Landscape Effects of Land Consolidation Projects in Central China——A Case Study of Tianmen City, Hubei Province

The goal of land consolidation in China is still to develop agricultural production.The study of landscape effects of land consolidation projects(LCPs)faces many difficulties because of the lack of government's interest and data.This paper,taking Tianmen City of Hubei Province in Central China as an example,presents a methodology for analyzing landscape effects of LCPs by GIS and Fragstats3.3.It describes landscape effects with indexes of Patch Density(PD),Largest Patch Index(LPI),Landscape Shape Index(LSI),Interspersion and Juxtaposition Index(IJI),Aggregation Index(AI),and Shannon's Diversity Index(SHDI),showing more regular shape,simpler structure and less habitat diversity after LCPs.It computes ten landscape indexes of four categories of patches including Cultivated Land,Road,Water Channel,and River and Pond.The indexes show that 1)cultivated land becomes more fragmental in patch area,less irregular in patch shape and more concentrated in block;2)the transport capacity of roads and irri-gation and drainage capacity of water channels have been improved;3)the landscape change of river and pond can be summarized as decreasing scale,more regular shape,reducing connectivity and diversity of the class.LCPs can facili-tate agricultural production as well as protect cultivated land and food security.However,it is doubted that the increase of cultivated land from LCPs results from the reducing in landscape diversity of water area.

Establishment of Rural Housing Land Standard in China

On the basis of rural household survey in 12 provinces of China in 2005,this research built an econometrical model to find the area standard for rural housing land.This standard is expected to facilitate rural housing land administration,efficient and intensive housing land use and policy making.This research concludes:1) according to the household survey data,the average area for rural housing land in China is about 235.26 m 2,and the rural housing land mainly includes unused land(42.89%) and house construction land(37.76%) with the average floor-area ratio of 0.42;2) the indexes in the standard concern the factors such as location,landform,house form,household population and cultivated land area per farmer,which all have significant effects on rural housing land use;3) the reasonable area for rural housing land may be 150 m 2 in average before 2020,and the referential standards in different provinces are 120 m 2,130 m 2,140m 2,150 m 2,160 m 2,170 m 2,190 m 2,200 m 2,210 m 2,220 m 2,230 m 2 and 250 m 2 respectively;and 4) if there are less than two persons or more than five persons in a family,these standards need to be decreased or increased by 7%.When the cultivated land area per farmer is lower than the provincial average,the standards have to reduce by 3.5%.

Land Use Regionalization of Rural Settlements in China

This paper compartmentalizes regional land use of rural settlements in China by employing a hierarchical clustering method.The statistic data are sourced from the National Bureau of Statistics of China(NBSC) and the data of land use change from the Ministry of Land and Resources of China(MLRC).The population of rural settlement decreases from the southeast to the northwest of China and the density of rural settlement decreases from the east to the west of China.Land-use scale of rural settlement,the proportion of one-storey houses and the average household area decrease from the north to the south of China.The ratio of area of cultivated land to rural settlement is high in the northeast and southwest of China but low in the southeast of China.The land use regionalization of rural settlement can be divided into four regions,namely:the northern region of China,Qinghai-Tibet,Yunnan-Guizhou,and the middle and eastern region of China.The northern region of China and the middle and eastern region of China can be further divided into nine sub-regions:Xinjiang,Northeast China,Ningxia and Inner Mongolia,North China,the south of the Changjiang(Yantze) River and Sichuan Basin,Jiangsu-Shanghai,South China,the Loess Plateau,and Guangxi.In consideration of the significant regional differences,it is proposed that different policies should be implemented regarding the utilization and management of rural settlements.

Decoupling Relationship Between Cultivated Land Occupation by Construction and Economic Growth in China During 1998-2007

With the rapid development of economy,the conversion of cultivated land into nonagricultural land occurs more frequently and makes cultivated land sparser.This article based on the decoupling theory takes the situations of cultivated land occupation by construction and economic growth in China from 1998 to 2007 as an example to evaluate and analyze the decoupling.The conclusions are drawn as follows.First,the article applies IU curve and gross method.The decoupling status by gross method,in contrast to that by IU curve,can express the pressure from cultivated land occupation better and is similar to the decoupling status based on the model of decoupling in this article.Second,in most provinces of China,the relationship between the cultivated land occupation by construction and economic growth has transformed from expansive negative decoupling to strong decoupling.In general,the transformation was firstly from economically advanced eastern municipalities under the central government directly,then to economically advanced eastern coastal provinces,and lastly to central,western and northeastern regions.Third,the decoupling status was relative to contemporaneous policies and laws on cultivated land protection and regional development planning.Their effect is obvious and positive.

Rare earth effect on the microstructure and tribological properties of FeNiCr coatings

FeNiCr alloys with various amounts of La2O3 powders were thermally sprayed onto steel substrate.Electron probe microscopy analysis （EPMA）,X-ray photoelectron spectroscopy （XPS）,and an Optimol SRV oscillating friction and wear tester in a ball-on-disc contact configuration were employed to investigate the properties of the sprayed coatings.The results show that rare earth can refine the microstructure effectively and make the element distribution uniform,which leads to the improvement in the properties of the coatings.Meanwhile,the wear rate of the FeNiCr alloy with 1.5% La2O3 is smaller than those of the other coatings.Interestingly,the rare earth can reduce the friction coefficient and act as a self-lubricant in the oxide debris layer formed on the worn surface in friction.The wear mechanism of the coatings is oxidation wear,and a large amount of counterpart material is transferred to the coatings.

基于OBE教学理念的《冲压工艺与模具设计》教学探索与实践

基于OBE教学理念,以缩短企业需求与学生所学知识间的差距、提高学生分析与解决冲压工艺、模具设计的工程实践能力、提高学生职业竞争力与专业自信为目标,对《冲压工艺与模具设计》课程进行改革。在课程教学中以工匠精神为魂,采用循序渐进的教学原则,"五化"教学方式,以冲压工艺分析与模具设计过程为导向的教学模式,加强课程过程考核的考核方法。学生课程综合成绩得到提高,冲压工艺分析、方案选择及模具设计能力得到锻炼。

GIS-Supported Precision Agricultural Fertilization Management at Small Scale

Precision agricultural fertilization technique at small scale is the key for regional cultivated land protection and management. Taking Dingzhuang Town (located in Guangrao County, Shandong Province) as a case study, this article explores the precision agricultural fertilization technique at small scale. First, three main cropping systems are identified via field investigation, namely "wheat–maize–soybean", "garlic–maize" and "cotton". Then, application amount of fertilizer N, P and K under the three cropping systems is calculated on the parameters acquired through field experiment, using nutrient balance approach on the support of geographic information system technique. The results indicate that, precision agricultural fertilization technique at small scale take on different characteristics compared with that at larger scale. The spatial distribution of soil nutrients in Dingzhuang Town is out of equilibrium, and huge amount fertilizer is needed to satisfy local agricultural production. There is huge distinction of fertilizer ap- plication amount under different cropping systems. The demand of fertilizer amount under "wheat–maize–soybean" system is larger than that under "garlic–maize" and "cotton" systems. This study can provide theories and principles for regional precision agricul- tural fertilization management.

富南灌区旱改水工程矩形渠技术应用分析

2014年富裕县富南灌区水利工程体制改革示范基地进行旱改水灌溉工程,项目区采用矩形渠技术新建斗农渠共计13009 m,经过多年的运行、观测,矩形渠工程运行良好,实现了水、土资源的高效开发和利用。并把矩形渠与传统土渠+预制混凝土板衬砌梯形断面渠道比较分析,说明矩形渠技术有诸多优点,是目前国内传统灌溉渠道防渗衬砌升级换代产品,值得大力推广应用。

The contribution of cultivated land occupation by construction to China＇s economic growth

The paper applies Cobb-Douglas Production Function and Solow-Swan Model to constructing the calculation model of the contribution rate of cultivated land occupation by construction （CLOC） to China＇s economic growth,and analyzes the contribution change of CLOC to China＇s economic growth qualitatively and quantitatively.The main conclusions are as follows：1） From 1989 to 2007,the contribution rates of capital,labor,and CLOC to China＇s economic growth were 45.76%,8.47%,and 6.19% respectively.2） From the period 1989-1996 to the period 1997-2007 the contribution rate of CLOC to China＇s economic growth increased from 5.40% to 5.87%.The degree of contribution was enhanced significantly.3） The contribution of CLOC to China＇s economic growth had a spatial distribution characteristic that the contribution rate of eastern coastal regions was the highest,that of central regions came second,and that of western regions the lowest.The paper indicates that in order to enhance the contribution of CLOC to China＇s economic growth,some relevant economic and administrative measures might be taken,and land might be used intensively and economically to increase land economic density.The cost of promoting gross domestic product （GDP） growth might be reduced as much as possible to achieve higher GDP growth and lower land resource consumption.

处理方法对钛合金摩擦磨损性能影响的研究进展

钛合金具有高的比强度、抗疲劳强度和抗腐蚀性能,但其表面硬度及抗磨损性能较差,提高其抗磨损性能一直是研究的热点。对改善钛合金的抗磨损性能的研究主要分为表面处理和整体处理两种方法。表面处理主要通过在钛合金的表面形成具有特殊作用的涂层或加工硬化层以提高其表面抗磨损性能;整体处理主要通过加入或合成具有高硬度的陶瓷成分强化基体以改善材料整体的抗磨损性能。两种处理方法对钛合金的强化机制相似,但整体处理方法对钛合金在苛刻条件下的应用更具有工程实际意义。