露空胁迫对管角螺成活率的影响

以不同发育阶段的管角螺为材料,研究了其在不同温度的干、湿环境下对露空的成活响应。实验结果表明,管角螺的成螺、幼螺及稚螺在低温湿润(18℃~20℃)的条件下可耐受更长的露空时间。成螺在低温湿润条件下露空72 h成活率达100%,但随着露空时间的延续,成活率降低,至10 d成活率降到10%。幼螺在同样条件下露空至72 h成活率为80%,稚螺为40%。而在高温(28℃~30℃)干燥的条件下干露相同的时间成活率明显降低,成螺72 h成活率为50%,至96 h全部死亡;幼螺72 h成活率为52.5%,稚螺68 h后全部死亡。在温度、湿度相同的条件下,管角螺耐露空能力为成螺>幼螺>稚螺。

露空对红树蚬生物标志物的影响

[目的]研究样品露空运输过程对红树蚬（Polymesoda erosa ）生物标志物的影响。[方法]野外采集的红树蚬经8℃、26℃和35℃露空处理8h，随后在26℃海水中暂养恢复3h、6h、12h 和24h，测定红树蚬血液超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、乙酰胆碱酯酶（AChE）、谷胱甘肽转硫酶（GST）活性，以及铁还原力（FRAP）和丙二醛（MDA）含量。[结果]8℃和35℃露空处理，SOD、CAT、AChE、GST、FRAP 和 MDA 均显著升高。26℃露空处理，SOD、AChE 和 MDA 显著升高，GST 显著降低，CAT 和 FRAP 有所降低但不显著。经过暂养，红树蚬各项指标均能恢复到初始水平，但24h 内波动较大。[结论]露空对红树蚬的生物标志物有显著影响。26℃露空8h 后，经3～6h 暂养，红树蚬生物标志物与初始水平最接近。

基于露空长度优化的盾构隧道下穿合肥火车站施工沉降控制探讨

为保证在地表注浆加固等常规措施难以实施的情况下盾构隧道顺利施工,以合肥市轨道交通1号线三期合肥站—瑶海公园站区间隧道在黏土地层中下穿变形控制标准严格的合肥火车站站房为例,结合工况分析盾构隧道施工引起车站变形的主要因素,提出以盾构姿态控制和同步注浆优化为主的盾构露空长度控制措施,并建立有限元仿真模型分析不同工况下车站受盾构隧道下穿施工的影响。研究表明:1)盾构刀盘超挖和盾构尾部露空均是引起盾构施工期间地层变形的主要因素,控制刀盘超挖和盾尾露空长度可以减小周边地层变形;2)在拟定优化施工方案下,隧道下穿施工对合肥火车站的影响基本可满足要求;3)建议采用洞内注浆和盾尾同步注浆优化方案降低施工风险,同时应控制盾构姿态以降低甚至消除刀盘超挖。

油气管道露空钢结构外防腐层设计标准对比及设计实践

目前油气管道工程的露空钢结构的外防腐层设计无相应的行标或国标,本研究通过介绍国际上较为成熟且广泛应用的标准ISO12944,详细对比了国内外各相关标准的内容组成以及各标准所采用的防腐层体系,指出目前国内标准与ISO12944相比在防腐层设计方面的差距和不足,介绍了目前国内油气管道工程的露空钢结构的外防腐层的设计现状。提出目前比较合理、可行的防腐层设计程序,并介绍了几个典型按照此设计程序进行防腐层设计实践的油气管道工程。

埋地管道露空后温度变化规律探讨

天然气集气管道常采用湿气输送工艺,其输送过程必须全面考虑温度变化规律,否则极有可能生成水合物,威胁流动安全。基于传热和对流理论,分析了常用计算模型,借助计算软件,探讨了由于施工、塌方等造成埋地管道露空后,管道温度变化规律,同时对比了不同风速下,管道的运行温度。本文的探讨成果,有助于集气管道投产后,评价露空工况下的管道温度降。

日周期光热干露胁迫对泰来草生理特性的影响

干露胁迫强度决定着海草床在潮间带的分布,植物的生理特性是反映其环境胁迫效应的重要依据。为探索潮汐周期内不同时长的光热干露胁迫对海草生理特性的影响,该文以热带优势海草泰来草(Thalassia hemprichii)为对象,通过在日光温室内模拟高温(41.0~44.5℃)和强光(633~1682μmol·m^(-2)·s^(-1))环境条件,研究不同露空时间(0、10、20、40、60、90 min·d^(-1),连续7 d)对泰来草叶片生长速率、光合色素含量和光合荧光参数,以及对叶片和根部抗氧化酶活性、非结构碳水化合物和次生代谢产物含量的影响。结果表明:(1)≤10 min·d^(-1)的日周期光热干露对泰来草的生长速率和生理特性未产生显著影响(P>0.05)。(2)在光热干露条件下,随露空时间的延长,泰来草叶片损伤逐渐加重,颜色由绿色变为褐色且生长速率降低,光合色素含量、叶绿素a/叶绿素b、叶绿素荧光参数均呈下降趋势;叶片和根的MDA、可溶性糖含量以及POD、SOD、CAT酶活性呈升高趋势;叶片淀粉、总酚和总黄酮含量呈先升高后降低的趋势。(3)90 min·d^(-1)的日周期光热干露是泰来草叶绿体PSⅡ光合反应中心不完全失活的承受极限。综上认为,潮汐周期内较长时间的光热干露胁迫会对泰来草的生长和生理特性产生负面影响,该研究结果为了解热带海草在潮间带的分布规律以及海草床生态修复时的位置选择提供了依据。

矿物油变压器注换两种酯类绝缘油的研究

本文主要研究了传统矿物油变压器注换酯类绝缘油包括天然酯及单酯绝缘油的可行性问题,首先研究了两种酯类绝缘油与矿物油混合后的常规电气、理化特性,在此基础上,分别使用两种酯类绝缘油对两台10 kV矿物油变压器进行注换,并测试注换前后变压器的整体特性。结果表明:使用单酯绝缘油注换矿物油变压器后,变压器的温升有所降低,对地电容提高且绝缘电阻下降;使用天然酯绝缘油注换矿物油变压器后,变压器的温升有所提高,对地电容提高且绝缘电阻下降。使用两类酯类绝缘油注换老旧矿物油变压器均具备可行性,且使用单酯绝缘油进行注换可提高变压器的散热能力,但应注意注换单酯绝缘油后变压器绝缘电阻的降低。

浸渍植物油对绝缘件影响的研究

首先将植物油暴露在空气中,测量其各项特性与露空时间的关系,然后观察浸渍植物油的绝缘件在空气中的氧化情况,进行传统气相干燥方法去除植物油的试验,最后采用电场解析软件对固体绝缘件在植物油变压器中的耐受场强值进行计算。结果表明:暴露在空气中后,植物油的含水量大幅增加,但其他特性变化不大,绝缘木块常温露空2个月后,表面并未产生氧化薄膜;气相干燥不能彻底除去绝缘件中的植物油;绝缘件在植物油变压器中承受的场强比同等结构矿物油变压器中高10%。

城市燃气户外立管腐蚀分析及选材研究

针对城市燃气户外立管日趋严重的腐蚀现状,通过对某燃气公司户外立管腐蚀的调查,阐述了影响地上管线腐蚀的主要原因,通过采集立管出地面附近的土壤对埋地管线和监测空气质量对露空立管进行腐蚀机理分析,并进行了土壤腐蚀环境和大气腐蚀环境的模拟实验,实验表明在立管出土部分埋地管线选材上宜选用3PE无缝20号钢管;而在露空立管选材上可使用000Cr17的薄壁不锈钢管。

STUDY ON HUMAN EXPOSURE ASSESSMENT TO INDOOR/OUTDOOR AIR POLLUTANTS

The environmental air quality is one of the important problems of people′s concern. The study on human exposure to air pollutants provides an important basis for the nuprorement of human health effects. The questionnaire about time activity patterns includes questions about time spent in the houses, personal activities, indoor combustion sources, information about hobbies, (e.g. smoking), home repairing and decorating materials, and personal product use and so on. The questionnaire was conducted with 662 respondents over 16 years of age in Tianjin, China from fall 1995 to summer 1996. The results of the investigation show that 84% of people′s activities happen indoors, and 58% in family. The field researches of air pollutants monitoring of the most important air pollutants either indoors or outdoors, including carbon monoxide (CO), formaldehyde (HCHO), inhaled particulate (IR), and Benzpyrene(Bap), were carried out in winter and summer from 1995 to 1996. The results of the study on human exposure to four selected air pollutants show that indoor sources and their air pollution cause relatively high exposure in the total air pollution exposures. For example, only the exposure indoors at home is 71.0%,60.3%, 69.4% and 74.0% respectively for CO, HCHO, IR and Bap in the total air pollution exposure.

Volatile Organic Compound Emissions when Drying Wood Particles at High Dewpoints

Emission of volatile organic compounds (VOCs) during drying of wood particles for particleboard manufacture, or for production of refined biofuels, is a potential environmental problem. The aim of this work is to study the emissions of VOCs during drying, and the influence on the emissions by different drying parameters.The experiments have mainly been done in a batch fluidized bed dryer, but measurements have also been done in a, pilot scale, continuous fluidized bed dryer. The parameters studied are air flow rate through the bed, air temperature, air dewpoint, and bed height. Since the present trend in biofuels and particle drying is towards very high dewpoints during drying, some measurements have been made at dewpoints up to 95℃, corresponding to a water content of 3.2 kg water per kilogram dry air. The emissions have been measured in two different ways,online during drying with a flame ionization detector and through wood analyses of the terpene content in the wood particles before and after drying. Substantial work has been made in developing the latter method as well as developing the drying equipment to be able to produce a wide range of conditions of the drying medium. It was shown that the VOCs emitted, during wood particle drying, mainly consist of terpenes. The behavior of the emissions was typical, at first contact with the drying gas a sharp peak in the release rate was detected. After that,the release rate stabilizes and declines slowly to a point where the material temperature increases and results in a second small peak in the release rate. Typically 80%-90% of the initial terpene content in the material was emitted during drying to low moisture content and it is not possible to significantly influence this release by changing the drying conditions. Up to 50% of the emitted terpenes are released during a very short period after contact with the drying medium. This fact could be utilized by employing a 2-step drying process. The fact that the VOC concentration in the inert gas gets much higher when drying at higher dewpoints could be taken into consideration when dealing with closed loop applications where the inert gas after the dryer is burnt.

Prevention and control of coalfield fire technology:A case study in the Antaibao Open Pit Mine goaf burning area,China

It is very difficult to clearly detect the location of a burning area in a coal mine since it is hidden underground.So we conducted research on the distribution of the burning area before controlling it.Firstly,the original drilling technique was used to analyze and determine the loose and scope of caving of burning area through field test,and then obtained the gases and the temperature data in this area were according to the borehole data.By analyzing these data,we found out that the location of burning area concentrated in the loose and caving area;and finally,the location and development of the burning area within the tested area were accurately determined.Based on this theory,we used the ground penetrating radar(GPR) to find out the loose and caving scale in the burning area during the control process of the burning area,and then located the fire-extinguishing boreholes within target which we used to control burning fire in the section.A mobile comprehensive fire prevention and extinguishing system based on the three-phase foam fire prevention and control technique was then adopted and conducted in the burning area which took only 9 months to extinguish the 227,000 m 2 of burning area of 9# coal.This control technology and experience will provide a very important reference to the control of other coalfield fire and hillock fire in the future.

In-situ decoration of metallic Bi on BiOBr with exposed(110)facets and surface oxygen vacancy for enhanced solar light photocatalytic degradation of gaseous n-hexane

Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is still rare.Here,a series of Bi/BiOBr composites were solvothermally synthe-sized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane.The charac-terization results revealed that both increasing number of functional groups of alcohol solvent(from methanol and ethylene glycol to glycerol)and solvothermal temperature(from 160 and 180to 200℃)facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates withexposed(110)facets.Meanwhile,chemical bonding between Bi and BiOBr was observed on theseexposed facets that resulted in the formation of surface oxygen vacancy.Furthermore,the synergis-tic effect of optimum surface oxygen vacancy on exposed(110)facets led to a high visible light re-sponse,narrow band gap,great photocurrent,low recombination rate of the charge carriers,andstrong·O2-and h*formation,all of which resulted in the highest removal efficiency of 97.4%within120 min of 15 ppmv of n-hexane on Bi/BiOBr.Our findings efficiently broaden the application ofBi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emittedby the petrochemical industry.

Cap rock blast caving of cavity under open pit bench

A laser technique based scanning system was employed to make a comprehensive scanning through borehole forunmapped cavity under open pit bench,then the three-dimensional data will be obtained,and these data were used for theoreticalanalysis and numerical simulation to analyze the stability of cap rock.Acoustic emission techniques were also adopted to carry outlong term real time rupture monitoring in cap rock.Therefore,a complete safety evaluation system for the cap rock was establishedto ensure safe operation of subsequent blasting processes.The ideal way of eliminating collapse hazard of such cavity is cap rockcaving through deep-hole blasting,thus,two deep-hole blasting schemes named as vertical deep-hole blasting scheme and one-timeraise driving integrated with deep-hole bench blasting scheme were proposed.The vertical deep-hole blasting scheme has moreexplosive consumption,but the relatively simple blasting net work structure can greatly reduce workloads.However,the one-timeraise driving integrated with deep-hole bench blasting scheme can obviously reduce explosive consumption,but the higher technicalrequirements on drilling,explosive charging and blasting network will increase workloads.

Flow structure around high-speed train in open air

According to the analysis of the turbulent intensity level around the high-speed train, the maximum turbulent intensity ranges from 0.2 to 0.5 which belongs to high turbulent flow. The flow field distribution law was studied and eight types of flow regions were proposed. They are high pressure with air stagnant region, pressure decreasing with air accelerating region, low pressure with high air flow velocity region I, turbulent region, steady flow region, low pressure with high air flow velocity region II,pressure increasing with air decelerating region and wake region. The analysis of the vortex structure around the train shows that the vortex is mainly induced by structures with complex mutation and large curvature change. The head and rear of train, the underbody structure, the carriage connection section and the wake region are the main vortex generating sources while the train body with even cross-section has rare vortexes. The wake structure development law studied lays foundation for the train drag reduction.

Spatial-temporal variance of reclamation soil physical and chemical character in opencast mine region

In order to study the effects of soil compaction, and soil physical and chemicalcharacteristics after land reclamation, selected lands that were reclaimed after 1, 2, 3, 4,and 5 a, respectively, in the Majiata Mine of the Shendong Open Pit; tested the effects ofsoil compaction; and collected soil samples from 5 different depths, which are 0-7.62,7.62-15.24, 15.24-22.86, 22.86-30.48, and 30.48-38.10 cm, respectively. The resultsshow that: Land reclamation leads to soil compaction. The lowest effect of soil compaction is in the top layer and the highest one at the depth of 20-30 cm; The bulk density of reclaimed soil is higher than that of undisturbed soil; this declines with the reclamation and nearly reaches the level of undisturbed soil after 5-year reclamation;The content of reclaimed soil nutrients is lower than that of undisturbed soil. The lowest one is inthe soil dumping site, which reaches the level of undisturbed soil after 5-year reclamation;The pH value of reclaimed soil is lower than that of undisturbed soil. The highest one isin the soil dumping site; this declines with the reclamation.

NIS One-Temperature Dew-Point Generator Operating in the Ranae -50℃ to 0 ℃

This paper describes construction and characterization of a dew/frost -point generator developed at national institute for standards. It is intended to operate in the range from -50 ℃to 0 ℃. The air flows through a saturator controlled by a regulated flow meter. The reference dew/frost -point temperature was measured by standard platinum resistance thermometer （SPRT） connected to a resistance bridge. A comparative study between the saturator temperature of the new generator measured by SPRT and the dew/frost-point temperature of a calibrated chilled-mirror hygrometer was conducted. It helped to determine the uncertainty of saturator; this uncertainty was found to be between ±0.06℃ to -4- 0.15℃ at confidence limit of 95%.Several experiments were carried out in the mentioned range. Obtained results gave the confidence that NIS generator could be used as a primary humid air generator.

Pressure Drop in Cyclone Separator at High Pressure

For the design of pressurized circulating fluidized beds, experiments were conducted in a small cyclone with 120 mm in diameter and 300 mm in height at high pressures and at atmospheric temperatures. Influence of air leakage from the stand pipe into the cyclone was specially focused. A semi-empirical model was developed for the prediction of the pressure drop of the cyclone separator at different operate pressures with the effect of air leakage and inlet solid loading. The operate pressure, air leakage and inlet solid loading act as significant roles in cyclone pressure drop. The pressure drop increases with the increasing of pressure and decreases with the increasing of the flow rate of air leakage from the standpipe and with the increasing of the inlet solid loading.

A STRONG OPTIMIZATION THEOREM IN LOCALLY CONVEX SPACES

This paper presents a geometric characterization of convex sets in locally convex spaces onwhich a strong optimization theorem of the Stegall-type holds, and gives Collier's theorem ofw* Asplund spaces a localized setting.