长垂直母线热压耦合厂房通风研究

大型地下电站发电机引出大多采用长垂直离相封闭母线(IPB),但在长垂直条件下因高度差产生的“烟囱效应”会导致母线上下温差过大,甚至超过母线最大运行工况下的温升限值,带来一定的安全隐患,并限制了地下电站封闭母线引出方式的运用。结合三峡地下电站等长垂直、大电流封闭母线竖井的特点,对长垂直封闭母线在不同影响因素下的热平衡特性进行了理论分析与数值计算。通过工程实践,探索出长垂直母线热平衡和地下厂房母线竖井通风的耦合模型及规律,并在此基础上提出了基于“热压耦合”的长垂直离相封闭母线的应用与通风设计的新思路。

光反馈诱发长波长垂直腔面发射激光器低功耗偏振开关

基于扩展的自旋反转模型,对光反馈诱发下长波长垂直腔面发射激光器中的低功耗偏振开关进行了理论研究.研究表明:长波长垂直腔面发射激光器在自由运行下未能获得的偏振开关现象,可以通过引入中等强度的偏振旋转光反馈来实现.对比强弱两种不同的线性色散效应,发现了一些有趣的现象:弱线性色散条件下更易于在低注入电流下获得偏振开关,并且产生偏振开关所需的反馈强度具有更大的调控范围;强色散效应中未能始终获得偏振开关,会出现两模共存区,并且偏振开关出现的注入电流值较高.同时,观察到的偏振模跳变和多偏振开关现象类似于短波长垂直腔面发射激光器,因而证实这两类激光器在偏振开关的本质规律上是相似的.此外,还对长波长垂直腔面发射激光器不易在低注入电流下获得偏振开关的原因进行了分析,并给出了合理的解释.

Seitevare水电站长垂直封闭母线设计考察与研究

结合对瑞典Seitevare水电站封闭母线生产设计厂家的实地考察,全面介绍了该水电站长垂直大电流封闭母线的设计、安装、运行情况及经验,并针对目前长垂直大电流封闭母线设计中的主要问题,如长垂直段母线的温度分布、导体和外壳的支撑方式、防凝露措施等,结合该电站的设计考察研究进行了深入分析,提出了长垂直段大电流母线温度分布的一般规律以及其它有益的建议。

某高土壤电阻率电厂中长垂直电解接地极的应用

在高土壤电阻率地区,采用局部扩大接地网面积或增加接地极埋设深度的方法对于降低电厂接地电阻的效果都不明显。本文针对具体案例,提出采用长垂直电解接地极的方法,解决了高土壤电阻率地区电解接地极的设计问题,实践证明该方法可经济有效地降低接地网的接地电阻值,且能够有效防止接地电阻的反弹。

新型材料InGaNAs的生长与应用前景

详细介绍了一种新型半导体材料(InGaNAs)的生长特点及其在制作高特征温度的长波长量子阱激光器、长波长垂直腔面发射激光器、长波长光泵垂直外腔面发射激光器、半导体可饱和吸收镜和长波长谐振腔增强探测器方面的优势。

火力发电厂高位布置封闭母线垂直段导体温升的研究

火电厂汽轮发电机组高位布置,发电机出口离相封闭母线布置为长垂直段型式;在高位布置下大电流、高垂直布置方式的基础上,对离相封闭母线导体的温升、散热、烟囱效应等进行了数据分析及计算研究,通过计算结果和数据比较,提出了离相封闭母线的导体及外壳选型建议。

Satellitic observation and genetic analysis of clouds of a Bohai sea effect snowstorm

In this study,substantial satellitic remote sensing data and atmospheric observational data were used to study a snowfall caused by Bohai sea-effect snow cloud which occurred in Shandong Peninsula from 4 to 6,DEC 2008.The study results show that the snow cloud emerged in the strong northwesterly cold flow in the middle-lower troposphere,the southwest of northeast cold vortex,and cyclonic bending on the surface pressure-field.Although the snowstorm cloud was shallow convective,its cold center was quite strong,the average snowfall rate was 0.41 mm/h during the exuberant period,and the snowfall rate was distributed in strip.The upwelling longwave fluxes on the cloud top were not only related to the temperature,but also related to the ice water content of the cloud,when we study the clouds effect on the radiation,we should consider the rainfall(snowfall)strength of the cloud.

水平层状介质条件下的井地电磁场响应计算

本文以垂直电偶极子矢量磁位的Sommerfeld积分表达式为基础,导出各含源层垂直分段电流源的电磁场沿导线方向的积分计算公式,进而得到各垂直分段电流源的电磁场。对各分段电流源的地面电磁响应进行叠加即可得到其井地电磁响应,从而将一维井地电磁正演问题简化为计算层状介质中垂直有限长电流源的地面电磁场问题。文中给出的算例验证了结果的可靠性,并与常规有限长电流源离散成多个小电偶极子源的近似方法计算时间及计算精度进行了对比,结果验证了算法的可靠性和高效性。

Pollen Record of Surface Sediments from Vertical Forest Zones of Changbai Mountain, Northeast China and Their Relations to the Modern Vegetation

Twenty-nine surface samples (mosses) from five vertical distribution vegetation zones in Changbai Mountain, Northeast China have been palynologically analyzed and the results were tested by correspondence analysis. The results show that, except a few samples, arboreal pollen is predominant in almost all pollen assemblages; Pinus and Betula are the main pollen types in quantities and they are found in all vegetation zones of Changbai Mountain. The highest pollen proportion of Pinus occurs in the mixed conifer and broadleaved forest where Pinus koraiensis is the main component; Betula pollen is found in high percentage in both subalpine B. ermanii forest and broadleaved deciduous forest predominated by Betula and Quercus; in the former Betula pollen is accompanied by cold-tolerant shrub such as Rhododendron; whereas in the latter it appears a large amount of fern spores. Pollen assemblage of broadleaved deciduous forests is marked by high diversity and proportions of deciduous trees and a large number of fern spores. Subalpine conifer forest is distinguished by high percentage of Picea pollen. Although tree pollen is slightly dominated, very few or absent of fern spores and increasing of herb and small shrub pollen proportions, particularly predominance of Rhododendron in herbaceous pollen and occurrence of tundra indicator type-Dryas pollen distinguish pollen assemblages of alpine tundra.

Prestack nonstationary deconvolution based on variable-step sampling in the radial trace domain

The conventional nonstationary convolutional model assumes that the seismic signal is recorded at normal incidence. Raw shot gathers are far from this assumption because of the effects of offsets. Because of such problems, we propose a novel prestack nonstationary deconvolution approach. We introduce the radial trace （RT） transform to the nonstationary deconvolution, we estimate the nonstationary deconvolution factor with hyperbolic smoothing based on variable-step sampling （VSS） in the RT domain, and we obtain the high-resolution prestack nonstationary deconvolution data. The RT transform maps the shot record from the offset and traveltime coordinates to those of apparent velocity and traveltime. The ray paths of the traces in the RT better satisfy the assumptions of the convolutional model. The proposed method combines the advantages of stationary deconvolution and inverse Q filtering, without prior information for Q. The nonstationary deconvolution in the RT domain is more suitable than that in the space-time （XT） domain for prestack data because it is the generalized extension of normal incidence. Tests with synthetic and real data demonstrate that the proposed method is more effective in compensating for large-offset and deep data.

我国南方四种植物的叶面积无损测定

利用阔叶图像分析系统WinFolia测定了我国南方阴香、三叉苦、九节和桃金娘4种植物的叶面积、叶周长、叶垂直长、叶水平宽和叶片长5项叶形态指标,通过方差分析和回归分析揭示各项指标的变异状况和指标间的相关性,探寻其叶面积无损测定方法及其可靠性。结果表明,叶面积的变异最大,其余4项指标变异程度接近,变异系数约为叶面积变异系数的1/2。叶面积与其余4项指标均呈极显著正相关(r>0.90,p<0.001)。综合考虑显示,叶垂直长、叶水平宽和叶片长均为准确可靠的叶面积无损测定指标。研究拟合出四种植物叶面积测定的回归方程,对今后开展叶面积测定及相关研究具有重要参考作用。

火电厂高位布置中离相封闭母线布置的研究

火电厂汽轮发电机组采用高位布置,发电机出口离相封闭母线的长垂直段布置在火电厂是全新的布置型式,该布置型式的确定对离相封闭母线的路径、应用及生产制造等均会产生影响。通过分析,结合其他水电机组工程中的设计、应用经验,得出离相封闭母线长垂直段的布置最优路径。

苏里格气田产量递减规律的综合研究与应用

苏里格气田属于典型的低渗透低丰度砂岩气田,气井产量递减速度快,开发难度大。及时了解气田所处的生产阶段,准确预测气田后期产量变化和可采储量是调整气田开发模式,合理配产,有效提高开发效果的有效手段。通过对苏里格气田苏25区块气井产量递减规律研究,确定了该区块的产量递减规律,利用产量递减资料,计算单井的裂缝半长,弥补了试井资料的缺陷,并对苏25区块生产周期内的月产量、可采储量以及采出程度进行了预测,预测结果与实际相符,可用于生产实际。

Advances of the Vertical Directional Solidification Technique for the Growth of High Quality GaSb Bulk Crystals

Advantages of the detached phenomena have influenced researchers to modify the conventional methods to promote it on the earth. Since 1994, the vertical directional solidification （VDS） technique has been employed for the growth of bulk crystals, without the seed, without contact to the ampoule wall, without coating and without external pressure. An automated furnace was designed and fabricated for the controlled temperature gradients, growth conditions and parameters. The typical ingots growths of GaSb have shown the gap of 20 μm-145 μm and mobility μn = 1125 cm^2/V.sec at 300 K. Mobility is highest and five times larger than the attached growths. Dislocation density is the order of 104/cm2 in the conical region, decreases in the direction of growth, and in many crystals reached less than 103/cm2. The spontaneous gap formation due to the meniscus depends on the pressure differences and thermal state. GaSb grown ingots have shown progress in the properties of crystal grown ever, and attributed to reduce thermal stress without contact to the ampoule wall.

Perpendicular intergrowth ZSM-5 plates with shortened 10-MR pores

ZSM-5 plates with a perpendicular intergrowth structure was synthesized by using a simple amine as the structure directing agent under hydrothermal conditions,in which the mother plate and the perpendicularly standing plates oriented along the(010)and(100)planes of MFI crystals,respectively.During the crystallization process,the mother plate was initially formed on the surface of the amorphous solid gel,while a set of parallel plates perpendicularly grew on its surface,via a homogeneous nucleation mechanism.The mother plate and the perpendicular plates had a similar thickness of 100-200 nm and were characterized by considerably shortened straight and zigzag 10 member ring pores,respectively.This unique intergrowth structure greatly facilitated the diffusion of the reactive molecules in HZSM-5 crystals during methanol conversion to hydrocarbons.

An Empirical Method for Estimating Background Stratospheric Aerosol Extinction Profiles over China

The current paper introduces an empirical method for estimating the vertical distribution of background stratospheric aerosol extinction profiles covering the latitude bands of 50±5°N,40±5°N,30±5°N,and 20±5°N and the longitude range of 75 135°E based on Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction measurements at wavelengths of 1020 nm,525 nm,452 nm,and 386 nm for the volcanically calm years between 1998 2004.With this method,the vertical distribution of stratospheric aerosol extinction coefficients can be estimated according to latitude and wavelength.Comparisons of the empirically calculated aerosol extinction profiles and the SAGE II aerosol measurements show that the empirically calculated aerosol extinction coefficients are consistent with SAGE II values,with relative differences within 10% from 2 km above the tropopause to 33 km,and within 22% from 33 km to 35 km.The empirically calculated aerosol stratospheric optical depths (vertically integrated aerosol extinction coefficient) at the four wavelengths are also consistent with the corresponding SAGE II optical depth measurements,with differences within 2.2% in the altitude range from 2 km above the tropopause to 35 km.

SPECIES COMPOSITION, HORIZONTAL DISTRIBUTION AND SEASONAL SUCCESSION OF PHYTOPLANKTON IN THE CHANNEL FROM DONGTING LAKE TO THE CHANGJIANG RIVER, CHINA

The species composition, horizontal distribution and seasonal succession of the phytoplankton at five sampling stations in the channel between Dongting Lake and the Changjiang River, China were studied from May 1995 to December 1997. A total of 416 taxa were observed; diatoms comprised the most diverse taxonomic group representing 58.2 % of the total species. The β-mesotrophic indicators were 92 taxa or 22 % of the total, the α-mesotrophic or α,β-eutrophic indicators decreased distinctly to 20 taxa or 4.8 % of the total. The species number and composition of various phyla were approximately similar at Stations 1, 2, 3 and 4, but at Station 5 the number of species was the minimum and the ratio of diatoms to total phytoplankton in the number of species was the highest. In seasonal succession of the phytoplankton species, the number was the highest in May and June, lower in December, January, March and July in the channel. The dominant species were different in different months. The ratio of diatoms species number to blue green algae and green algae species number diminished gradually from winter to summer and autumn, and then increased gradually from autumn to winter and early spring in the annual cycle. Margalef, Simpson and Shannon-Weaver diversity indices changed in different months, their values were higher in winter, lower in summer. Nygaard’s diatoms quotients were lower in winter, then in spring and autumn, higher in summer. These results indicated that the water quality was the best in winter, better in spring and autumn than in summer. The relationship between the structure of the phytoplankton community and the water environmental quality was discussed.

Vertical structure and dominating factors of sand body during Late Triassic Chang 9 time of Yanchang Formation in Ordos Basin, NW China

Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel,natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform + infundibuliform, campaniform + infundibuliform, box shape + campaniform, box shape + infundibuliform,and finger + finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment,sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.

Advances of the Vertical Directional Solidification Technique for the Growth of High Quality InSb Bulk Crystals

Since 1994, the vertical directional solidification （VDS） technique is employed for the growths of bulk crystals-without the seed, without contact to the ampoule wall, without coating and without external pressure, which leads to the detached growth. Growth velocities ranged from 3 mm/h to 10 mm/h, and rotation rates 10-20 rpm have been used. Ingots, 10-20 mm diameter and 60-65 mm length, have been grown with the conical ampoule geometry and these ingots have shown symmetric detachment. Crystals grown under such conditions showed the relatively low dislocation density and the highest carrier mobility,/tn = 5.9 x 104 cm2＂Vl-sl than the crystal grown ever. For the detached crystals, the dislocation density is 104 cm＂2 in conical region, and reached less than 103 cm-2 in the direction of the growth, when the ingots are not in contact with the ampoule wall. Experiments for indium-antimonide （InSb） growth have shown that the 80% growth environments have detachment, 15% entrapped in conical region and 5% attached.

Development of a Cylindrical Hydroponics System for Vertical Farming

The study aimed to develop a vertical crop cultivation system for leafy plants based on cylindrical hydroponics and light emitting diode （LED） technology. Investigations were conducted on growing lettuce （Lactuca sativa cv. ＂Rex＂, ＂Nanda＂ and ＂Canasta＂） indoors in a rotary system and Chinese cabbage （Brassica chinensis） in a multi-tier cylindrical hydroponics system under red and blue （RB） LED lightings. Light intensity from different light sources have an influence on the yield and growth behaviour of indoor lettuce. Photosynthetically active radiation （PAR） levels at 63 μmol/m2·s produced low fresh weights （FW） and leaf areas of lettuce ＂Rex＂ and ＂Nanda＂ were grown under rotating conditions. The effect was, however, different on the better developed ＂Canasta＂. Stem etiolation was a common occurrence under such influence. Chlorosis was not observed on all plant types grown under the LEDs. Cultivating Chinese cabbage plants （FW： 28 g/plant） in cylindrical units stacked vertically above another, increased planting density by 47% when compared to the rotary system,