输变电线路工程施工中技术问题及处理措施的探讨

输变电线路是一项复杂、专业的系统工程,需要统筹建设才能保证工程的顺利建设以及工程质量。输变电线路承载着国家对一个地区的发展希望,输电线路的可靠运行,将直接为一个地区的发展提供可靠的支撑点。     

输变电工程穿越湿地类型自然保护区生态影响及措施探讨——以十堰-卧龙500 kV输电线路工程为例

指出了输变电工程经常存在跨越自然保护区的情况,在施工和运营过程中可能造成自然保护区的生境破坏。输变电工程如何在自然保护区内施工、运营和管理成为关注的重点。以十堰-卧龙500 kV输电线路工程为案例,在总结生态影响的基础上提出了合理可行的生态环境保护措施,为类似工程的生态保护提供经验和科学参考。     

东莞市某500kV变电站及输电线路电磁场水平调查

以东莞市某500kV变电站及输电线路为研究对象,通过全方位现场监测及数据分析,根据《电磁环境控制限值》(GB8702-2014)中规定的标准限值进行了综合评定。探究了500kV变电站的工频电磁场水平和日内变化规律,为让公众进一步了解和认识输变电工程的电磁场辐射水平和对人体健康的影响,及为变电站的建设及规划提供科学的参考依据。     

清原县征占用林地管理办法

<正> 第一条为了加强林地管理,保护发展森林资源,根据《中华人民共和国森林法》、《中华人民共和国土地管理法》及省、市有关规定,制定本办法。第二条凡在本县行政区内修筑工程设施、架设线路、开采矿藏、勘测、采石取土及其他建设需要,征占用林地,适用于本办法。     

电力调控中继电保护的应用

在我国电网的现代化建设过程中,信息技术不断地进步和发展,我国电网规模也在迅速地增长和扩大.同时,我国变电站也朝着智能化方向前进和发展,各种智能设备在变电站领域中的应用也越来越广泛,使得输变电系统相关的工作效率和安全性得到了有效改善和提高.介绍了智能化变电站继电保护装置存在的问题,着重分析了加强继电器保护在电力调控中应用...     

绿海短波

云南省出台《关于继续推进天然林资源保护工程的意见》云南省人民政府近日出台了《关于继续推进天然林资源保护工程的意见》。明确了全省天保工程二期建设的具体目标和主要任务,对全省天保工程二期建设提出了具体要求。     

宜昌市古树名木资源调查及保护对策

为加强古树名木保护,推进生态文明建设,综合运用每木调查、查阅资料、线路调查、座谈走访等方法系统调查了宜昌市古树名木资源,简要分析了宜昌市古树名木的种类、分布、数量和生长状况,提出了进一步加强古树名木资源保护的对策和建议.     

达拉特旗林地保护利用探讨

林地是森林资源的重要组成部分,是国家重要的自然资源和战略资源,是林业生产建设的根基,也是生态建设和经济社会可持续发展的物质基础和保障.国务院批复国家林业局《关于地区“十一五”期间年森林采伐限额审核意见的通知》中明确提出,要依法编制林地保护利用规划;国家林业局颁布的《全国林地保护利用规划纲要（2010～2020年）》中明确提出,要建立全国县级林地保护利用规划纲要,为县级林地保护与利用指明了方向.     

浅谈青龙河重要湿地价值及亟须解决的瓶颈问题

为贯彻国家湿地建设和保护战略,加快凌源湿地资源保护与利用工作步伐,按照＂保护优先、科学修复、适度开发、合理利用＂的原则,根据《国家湿地公园管理办法（试行）》和《辽宁省湿地保护条例》的要求,结合我市实际情况,拟在青龙河流域建设重要湿地及湿地公园项目。本文从凌源市青龙河湿地现状出发,阐述了建设青龙河重要湿地的价值,探讨了亟待解决的瓶颈问题。     

利用超声测钎对秦岭特高压工程土壤流失的研究

为研究输变电工程建设期间及建设后对秦岭地区水土流失带来的影响,对近年来有输变电工程建设的秦岭的不同地区为研究对象,利用超声测钎法对研究地区的土壤流失量的影响因素进行探究.结果表明:研究地区水土流失程度与时间、坡度和地理位置有一定的相关性.     

Living snow fences show potential for large storage capacity and reduced drift length shortly after planting

Living snow fences are windbreaks designed to mitigate blowing snow problems by trapping snow in drifts before it reaches a road. Research studies on living snow fences are limited and extension publications consequently lack precise design protocols. This study investigated 18 sites in New York State planted with living snow fences of various vegetation types and ages ranging from 1 to 11 years after planting. Key plant growth variables of fence height and optical porosity were measured along with distance upwind and downwind. This data was combined with site specific snowfall estimates and established equations to calculate the snow storage capacity of each fence, average annual snow transport (blowing snow) at each site, and length of the downwind drift. Capacity/transport ratio of each fence/site was identified as a key variable. Height increased linearly over time and porosity decreased. Three years after planting, height and porosity was sufficient so that capacity/transport ratios were greater than 1:1, indicating substantial snow trapping potential much sooner than commonly reported. Four to eleven years after planting, capacity/transport ratios were between 3:1 and 110:1. Capacity/transport ratios of 15:1 or greater occurred as early as 5 years after planting and were correlated with estimated drift lengths <10 m. The influence of capacity/transport ratio on drift length is not accounted for in current publications and setback recommendations range from 30 to 180 m. The results of this study can improve the understanding, design and function of living snow fences.     

5种红山茶叶绿素荧光特性的比较研究

在大四条件下，通过对五种红山茶的叶绿素荧光特性研究，结果表明，不同亚组、同一亚组不同系之间的叶绿素荧光参数值存在差异．且亚组间大于亚组内。初始荧光(FO)、最大荧光(Fm)、RSⅡ最大光化学效率(Fv／Fm)、PSⅡ实际光化学效率(Yield／ΦPSⅡ)、表观电子传递速率(ETR)的日变化与光强有关．其中，Fm、Fv／Fm、Yield随光强的变化呈相同的变化趋势，呈单谷曲线；而ETR则相反呈单峰曲线；FO呈双峰曲线。不同树种的荧光参数日变化幅度存在差异。     

Recovery of photosynthesis in 1-year-old needles of unfertilized and fertilized Norway spruce (Picea abies (L.) Karst.) during spring

Photosynthetic O(2) evolution and chlorophyll a fluorescence were measured in 1-year-old needles of unfertilized and fertilized trees of Norway spruce (Picea abies (L.) Karst.) during recovery of photosynthesis from winter inhibition in northern Sweden. Measurements were made under laboratory conditions at 20 degrees C. In general, the CO(2)-saturated rate of O(2) evolution was higher in needles of fertilized trees than in needles of unfertilized trees over a wide range of incident photon flux densities. Furthermore, the maximum photochemical efficiency of photosystem (PS) II, as indicated by the ratio of variable to maximum fluorescence (F(V)/F(M)) was higher in needles of fertilized trees than in needles of unfertilized trees. The largest differences in F(V)/F(M) between the two treatments occurred before the main recovery of photosynthesis from winter inhibition in late May. The rate of O(2) evolution was higher in needles of north-facing branches than in needles of south-facing branches in the middle of May. Simultaneous measurements of O(2) exchange and chlorophyll fluorescence indicated that differences in the rate of O(2) evolution between the two treatments were paralleled by differences in the rate of PS II electron transport determined by chlorophyll fluorescence. We suggest that, during recovery of photosynthesis from winter inhibition, the balance between carbon assimilation and PS II electron transport was maintained largely by adjustments in the nonphotochemical dissipation of excitation energy within PS II.     

栓皮栎物候期统计分析

通过样株物候观测记录、资料利用,典范相关分析,揭示出一组花变量和一组叶变量之间高度关联。     

Predicting equations of main factors affecting regional climate in the "Three-North" Protective Forest Area

lntroductionInordertosolvetheseriousecologicaIproblemwefacedandimprovethephenomenonoflanddesertifi-cationinthenorthareaofChina.ChinahasbeguntoconstructtheThree-NorthProtectiveForestSystemsince1978.Withthehardworkoftwentyyears,itistold"Thegreatestecologicalprojectoftheworld"and"ThegreengreatwaIl".AIthoughthecountryinvestedIotsofcapitaItobuiIdtheThree-Northshelter-forestsystemthroughmanywayssuchasThree-Northspecialinvestment,financeappropriatefunds,finan-cialloansandtakeoutfundsforbringup…     

多通道传感器供电电源设计

基于充电专用芯片UC3906的结构与工作原理设计多通道传感器供电电源系统,主要包括：电池充电电路设计、电池电压状态指示电路设计和DC-DC电压转换电路设计,并给出这3种电路的具体设计过程。     

油松树干横截面面积年增长量的垂直分布及与材积年增长量和叶量的关系

【目的】揭示油松树干横截面面积年增长量(RAI)的垂直分布特征和主要控制机制,验证Cortini等(2013)建模方法和模型形式在油松上的应用效果,确定基于RAI模拟预测材积年增长量和单木叶生物量的理想模型和树干位置。【方法】在9个不同年龄和竞争状态的油松林内选取27株10~98年生样木,于不同树干位置截取312个圆盘测算并分析各样木的RAI垂直分布模式,比较其与各理论模式的异同,揭示相关机制;基于Cortini等(2013)建模方法和模型形式构建油松RAI垂直分布模型,根据拟合优度等验证并评价其应用效果;在不同RAI垂直分布模式和整体水平,比较分析不同树干位置RAI与全树干水平的差异及与材积年增长量和单木叶生物量的关系,确定理想模型和树干位置。【结果】油松RAI垂直分布包括2种模式,差异主要源自树干中间区,有效树冠区和膨大区RAI分布分别与水分传输和机械支持的理论模式相近,而中间区RAI分布与各理论模式的异同因样木而异;RAI垂直分布模型可解释其垂直变异的82.76%;不同模式和整体水平,有效树冠基部RAI与全树干水平的差异均小于其他位置,胸高处RAI与单木叶生物量的关系均优于其他位置,而与材积增长量的异同因模式而异,或优于其他位置或略差于理想位置。【结论】水分传输和机械支持需求分别决定有效树冠区和膨大区的RAI垂直分布,二者的相对重要性及生物环境等因子共同决定树干中间区的分布;Cortini等(2013)建模方法和模型形式在油松上的应用效果良好;有效树冠基部对全树干水平的代表性较高,在胸高处测算RAI并据此预测材积年增长量是有效但存有缺陷的方法,对单木叶生物量的模拟预测效果良好。     

多形林分生长模型研究

为了减少自变量,避免出现因子间相互预测,精确描述样本数据,有效减小系统误差,文章以一平浪林场为例,介绍了只选择年龄单因子为自变量构成建云南松多形树高生长模型的方法.该生长模型可用于云南松的生长预估及计算机仿真.     

Mass and heat transfer mechanism in wood during radio frequency/vacuum drying and numerical analysis

The mass and heat transfer mechanisms during radio frequency/vacuum(RF/V) drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport phenomena of mass and heat during continuous RF/V drying was derived from conservation equations based on the mass and heat transfer theory of porous materials. The new model provided a relatively fast and efficient way to simulate vacuum drying behavior assisted by dielectric heating. Its advantages compared with the conventional models include:(1) Each independent variable has a separate control equation and is solved independently by converting the partial differential equation into a difference equation with the finite volume method;(2) The calculated data from different parts of the specimen can be displayed in the evolution curves, and the change law of the parameters can be better described. After analyzing the calculated results, most of the important phenomena observed during RF/V drying were adequately described by this model.     

Predicting equations of main factors affecting regional climate in the “Three-North” protective forest area

The relationship between the change of forest resources and climatic factor in the, “Three-North” region of China were studied in this paper. The predicting equations of climatic factor (dependent variable) with regional independent variable (longitude, latitude and altitude) and stand independent variable (forest coverage rate), were developed by extensively using the linear and nonlinear regression methods. With these models, we can calculate the ecological benefit of Shelter-belt forest. Responsible Editor: Chai Ruihai