浅析步进电机的发热与安全

分析了步进电机发热的原因及发热带来的影响，提出了如何减少步进电机发热的方法。     

设计火灾时火灾热释放速率曲线的确定

在运用火灾计算机模型进行建筑物性能化消防设计与评估时,确定合理、切合实际的火灾的热释放速率曲线非常重要。基于当前国内外的研究现状,本文提出了几种符合当前技术水平且实用的确定火灾热释放速率曲线的方法,对于每种分析计算方法及其适用条件进行了详细阐述,并给出了相关的计算实例。     

宝玉石改色原理与辐照改色宝石的残余放射性

传统的宝石改色是以泰国的还原热处理工艺为代表，现已逐渐被人们所接受。现代科技与珠宝工艺相结合，出现辐照改变宝石颜色，然而，部分宝石因辐照而带有残余放射性，对消费者造成伤害．本文指出了宝玉石射线来源与防护措施。     

炭黑尾气净化及余热利用

对炭黑生产尾气中ＣＯ，Ｈ２及ＣＨ４等可燃气态污染物的净化及其余热的回收和利用进行了研究，结果表明，采用直接燃烧法是目前我国炭黑尾气净化和余热回收利用的最佳方法，直接燃烧法，不仅可将黑尾气中可燃气态污染物变为无害的物质ＣＯ２和Ｈ２Ｏ，并可回收和利用热，可使炭黑生产余热利用率提高５０％以上，其经济效益和环境效益十分可观。     

THERMAL AND DISSOLVED OXYGEN CHARACTERISTICS OF A SOUTH CAROLINA COOLING RESERVOIR1

ABSTRACT: Temperature and dissolved oxygen concentrations were measured monthly from January 1971 to December 1982 at 1-m depth intervals at 13 stations in Keowee Reservoir in order to characterize spatial and temporal changes associated with operation of the Oconee Nuclear Station. The reservoir water column was i to 4°C warmer in operational than in non-operational years. The thermo-dine was at depths of 5 to 15 m before the operation of Oconee Nuclear Station, but was always below the upper level of the intake (20 m) after the station was in full operation; this suggests that pumping by the Oconee Nuclear Station had depleted all available cool hypolimnetic water to this depth. As a result summer water temperatures at depths greater than 10 m were usually 10°C higher after plant operation began than before. By fall the reservoir was nearly homothemious to a depth of 27 m, where a thermocine developed. Seasonal temperature profiles varied with distance from the plant; a cool water plume was evident in spring and a warm water plume was present in the summer, fall, and winter. A cold water plume also developed in the northern section of the reservoir due to the operation of Jocassee Pumped Storage Station. Increases in the mean water temperature of the reservoir during operational periods were correlated with the generating output of the power plant. The annual heat load to the reservoir increased by one-third after plant operations began. The alteration of the thermal stratification of the receiving water during the summer also caused the dissolved oxygen to mix to greater depths.     

济南市局地环流数值预报试验研究

利用多尺度气象耦合模式对济南市城市热岛和山谷风局地环流进行了数值预报试验,其预报和实测日均风速比值总体平均为1.18±0.39,风向差值总体平均为45±30°,温度差值总体平均为0.32±0.25(°C)。     

鼎湖山主要森林生态系统地表N_2O通量

利用静态箱-气相色谱法对鼎湖山3 种处于演替不同阶段的森林类型(季风常绿阔叶林、针阔叶混交林和马尾松林)的地表N2O 通量进行了 1 年的原位观测和研究.结果表明,3 种林型地表 N2O 通量按从大到小的顺序为:季风林>混交林>松林;不同林型间的 N2O 通量差异与森林土壤的性质有密切关系,C/N 比值较低的季风林凋落叶对土壤中产生N2O 的微生物过程有较为明显的促进作用;从全年来看,松林地表N2O 通量的季节变化不明显,而季风林和混交林的地表 N2O 通量在雨季存在明显的降雨驱动效应,统计分析显示在该地区影响森林地表N2O 通量的主要因子是土壤湿度.     

Climatic Variation and Solute Concentration and Flux in Meltwaters Draining from an Alpine Glacier

Measurements of electrical conductivity and discharge ofmeltwaters in the Gornera, which drains from the 83%glacierised basin containing Gornergletscher, PennineAlps, Switzerland, were undertaken between May andSeptember in both 1979 and 1998. Discharge in theGornera was 43% higher in 1998, average air temperatureduring the ablation season being 2.1 °C warmer andpreceding winter precipitation 28% lower than in 1979. Mean electrical conductivity of meltwater in 1998 wasreduced by 40%. In the same 60 day period in 1998,however, solute flux was augmented by only 2% bycomparison with 1979. Year-to-year climatic variations,reflected in discharge variability, strongly affectsolute concentration in glacial meltwaters, but havelimited impact on solute flux. Climatic conditionstranslate into meltwater quality through inter-relationships between mineral reaction rates, subglacialresidence time in contact with sediment, and discharge. Annual variability in solute flux depends on the extentto which volume of flow can offset decline in soluteconcentration brought about by reducing residence time.     

Estimating Time Windows for Burning Oil at Sea: Processes and Factors

This paper discusses processes and factors for estimating time period windows of in situ burning of spilled oil at sea. Time-periods of in situ burning of Alaska North Slope (ANS) crude oil are estimated using available data. Three crucial steps are identified. The First Step is to determine the time it takes for the evaporative loss to reach the known or established limitation for evaporation and compare this time-period with estimated time of ignition at the ambient wind and sea temperatures. The Second Step is to determine the water up-take of the spilled oil and compare it with the known or established limitation for water-in-oil content. The Third Step is to determine the necessary heat load from the igniter to bring the surface temperature of the spilled oil to its flash point temperature so that it will burn at the estimated time period for ignition of the slick.     

真鲷去毒相关基因cDNA序列的克隆与肝脏组成型表达分析

赤潮发生时产生的一些海洋生物毒素对人类和海洋动物的安全形成潜在的威胁甚至导致死亡.为从分子水平探讨鱼类中海洋藻毒素的去毒分子机理,采用RT-PCR法克隆了真鲷(Pagrus major)肝脏芳香烃受体核转位蛋白(ARNT)和I时相异生素代谢酶细胞色素P4501A(CYP1A)基因cDNA核心序列,同时,应用半定量RT-PCR方法,以β-肌动蛋白作为外参照,在其指数期增长的范围内研究了芳香烃受体(AHR)、ARNT、CYP1A、II时相异生素代谢酶alpha型谷胱甘肽S-转移酶(GSTA1、GSTA2)、rho型谷胱甘肽S-转移酶(GSTR)、热休克蛋白70(HSP70)基因组成型表达水平.结果发现,真鲷ARNT、CYP1A基因cDNA核心序列片段分别长438bp和908bp,分别编码146和302个氨基酸.序列同源性分析发现,真鲷与门齿鲷(Stenotomus chrysops)、石首鱼(Micropogon undulatus)ARNT基因氨基酸序列同源性高达97.2%、95.2%,与斑马鱼(Brachydanio rerio)、人、大鼠、小鼠ARNT同源性较低(77.2%～79.3%).真鲷与门齿鲷、金头鲷(Sparus auratus)、欧洲川鲽(Rhombus maximus)、欧洲海鲈(Dicentrachus labrax)CYP1A基因氨基酸序列同源性较高,为84.8%～94.0%,与斑马鱼、人、小鼠CYP1A同源性较低,为59.6%～77.8%.真鲷肝脏AHR、ARNT、CYP1A、GSTA1、GSTA2、GSTR和HSP70基因组成型表达水平分别为(25.32±6.56)%、(26.22±4.24)%、(146.5±16.06)%、(55.42±3.75)%、(48.82±10.89)%、(79.47±3.13)%、(107.42±14.34)%.