开关柜作为配网系统中的主要设备之一,其安全性及可靠性对于保证电网安稳运行至关重要.局部放电现象是造成开关柜绝缘故障的最主要表现,如何有效监测运行中的开关柜局部放电现象,及时发现潜在的绝缘风险是电力部门关心并亟待解决的问题.本文提出了一套开关柜局部放电在线监测系统,该系统基于电容耦合高频脉冲电流法,可对开关柜局部放电现象进行有效监测,并且通过试验方案对系统可行性进行了验证.

According to detection and monitoring of soil salinity,feasible water and salinity control program was formulated.Fulvic acid was taken as chemical modifier to modify saline-alkali soil under mulched drip irrigation,and cotton growing and production were analyzed.The results showed that:with the increase of irrigation time and irrigation volume,soil salinity first decreased significantly,then locally rose;After farmland being modified,soil pH,total soluble salt,SO24-,HCO3-,Mg2+,Cl-,Ca2+,K++ Na+all decreased significantly;Plant height,bolls number,stem diameter,leaf area,and yield of 3growing types in modified area were all better than those in the unmodified area.

The water environment has a direct effect on the adsorption and desorption behavior of thallium (Tl) in sediments and further influences its transportation and transformation. In this study, the adsorption behavior of Tl(I) and the effect of pH on the adsorption in sediments taken from Liangshui River of Beijing (L8) and the nearby lotus pond (L6) was investigated. In addition, background electrolyte and sediment leaching solutions were used as the desorption system to examine the desorption characteristics of adsorbed Tl(I) from the sediments. Results indicated that the rates of absorption of Tl(I) onto both sediments were relatively fast, with adsorption capacities reaching 90% of the maximum (L6) and over 80% of the maximum (L8) in the initial five minutes, and the adsorption equilibrium was reached after 12 hours of reaction. With the increased initial concentration of Tl(I), the adsorption capacities of Tl(I) in sediments of L6 and L8 increased, and the adsorption capacity of Tl(I) on L6 was remarkably higher than that of on L8. Adsorption isotherms of Tl(I) on the two sediments fit well with both the Freundlich and Langmuir equation. On the analysis of mechanism of adsorption and desorption, the Langmuir equation could better illustrate its chemical and physical properties than that of Freundlich equation. pH had a great effect on the adsorption of Tl in sediments. The adsorption capacity increased gradually with the increase of the pH. The sediment leaching solution was characterized by high pressure size exclusion chromatography (HPSEC) and fluorescence excitation-emission matrix (EEM) spectrometry. The results showed that the main components in the leaching solution were proteinoid and humic substance with fluorescence intensity between 1100 and 1550. When the sediment leaching solution was used as desorption system, the desorption amount of Tl(I) increased about 2.232 mg · kg-1 (L6) and 1.494 mg · kg-1 (L8) (C0=0.33 mg·L-1). Desorption of Tl(I) in the sediment leaching solution was easier compared to NaNO3 background solution, leading to a release of Tl(I) back into the water environment.

the intake tower vibration was very severe when the flood discharge tunnel of Wudao reservoir was working at high water level.In order to investigate the vibration causes and provide a basis for the reinforcement design,the hydraulic prototype model test with scale 1:20 of the flood discharge tunnel was conducted.Pressure pulsation characteristics on the wall of the tunnel and the working sluice gate were studied.Self-vibration characteristics of the tower were analyzed and the vibration response was predicted through finite element method simulation.The research shows the low step self-vibration frequencies of the intake tower were not fully breaking away from the high energy zone of the dynamic water which would induce severe vibration.The vibration response of the tower was bigger relatively when it was working upon 0.4 opening.The maximum acceleration of the design water level was about 0.34g,and appeared in the bottom of the tower,which was consistent with the prediction of the prototype observation.

A study was carried out to develop irrigation schedule for alfalfa in Aksu as an example.In use of Penman-Monteith formula,T-ET functional model of crop irrigation schedule was established through the function of crop growing days and water requirement.The results show that,irrigation should be made 25 times annually with a total irrigation amount of 750 mm when the irrigation was designed as: using 32# spray nozzle,with a spray range of 20 m,flow rate of 4.71 m3/h,effective control area of 315 m2 and irrigation intensity of 14.95 mm/h.The water requirement regulation of alfalfa and the corresponding irrigation schedule can be obtained by using the model,which is practical way to make irrigation schedule and promote water use efficiency in certain regions.

<正>吐哈盆地是中国著名葡萄生产基地,也是严重资源性缺水的极端干旱区。在农田水分循环过程中,葡萄棵间土面蒸发是水分散失的一个重要环节。准确测定葡萄灌溉期棵间土面蒸发量及变化规律,对于葡萄园采用科学的节水措施及制定合理的灌溉制度具有重要的意义。微型蒸发

中国古代有各种忌讳,其中的文书避讳是中国古代社会的一种制度,是忌讳的延续和传承。避讳虽然对文书工作产生一定的影响,但是如果人们掌握了它的规律,却可以利用避讳来鉴别史书和史料的真伪。

An introduction is being presented to the working principle of an electrical precipitator,while its theoretical power consumption calculated.Some energy-saving measures were proposed and taken,of which the specific retrofit process described.Actual measurements prove the retrofit to be successful,i.e.obvious retrofit effects obtained and energy-saving purposes achieved.

Present gas explosion model and formulas which contain the parameters of initial pressure and initial temperature were employed to study the influence of initial temperature and initial pressure on gas explosion parameters.A calculation program was written with Visual Basic,and the calculation results were in good agreement with those published in literatures.Taking CH4-air mixture as an example,detonation parameters were calculated at 98 000 Pa,280-400 K and 298 K,0.1-0.5MPa.The calculation results show that,when initial pressure is fixed,the detonation pressure of mixture decreases with the increase of initial temperature,while detonation velocity keeps approximately stable;when initial temperature is fixed,the detonation pressure increases with the increase of initial pressure,and the detonation wave velocity almost keep the same;the influence of initial pressure on detonation parameters was much greater than that of initial temperature on detonation parameters.

Experiments of gas explosion inducing coal dust explosion were carried out in the large experimental laneway,and a comparative analysis was made on the experimental data including explosion pressure and flame generation,promotion and propagation.It is concluded that the pressure wave has pass-back phenomenon during the process of gas explosion inducing deposited coal dust;In the position where coal dust is initially involved in exposition,the explosion overpressure appears for a long duration.The propagation velocity of explosion flame rises rapidly alone the path covered with coal dust,and then it changes to a steady increase in the end of the path and finally it begins to decrease after the path.The length of flame zone is as twice as that of dust zone.These regularities provide the theoretical basis for preventing gas and dust explosion efficiently.

Based on the characteristics of surface water contaminated by oil,the growth curve of Microbacterium sp.that can degrade oil was studied,which provided the theoretical evidences for immobilization of bacterium.The modified immobilized Microbacterium sp.was used to bioremediate the oil-contaminated surface water.The oil removal ability was determined under various amounts of inoculation and different initial oil concentrations.The inoculation capacity suitable to immobilize cells was 10%.At initial concentration of 150 mg·L-1,the immobilized Microbacterium sp.can remove 75.6% oil from the contaminated surface water in 48 hours,much higher than the removal rate 62.3% by free ones.Besides,the immobilized Microbacterium sp.had good regenerative ability and could be repeatedly used for long time.The immolibized Microbacterium sp.endured a wide range of pH of wastewater,demonstrating the high activity of the strain.The SEM analysis showed that the micro-structure of immobilized cells was fit for the growth of Microbacterium sp.,providing theoretical basis for the application of immobilized microorganisms in remediation of surface water contaminated by oil.The immobilized technology had the advantages over the normal free micro-organisms method,and using microbial immobilized technology in the treatment of oil wastewater had a broad prospect.

The problems caused by oil pollution in surface water have gradually become more serious.Traditional remediation technologies for oil pollution in surface water are difficult to implement because of its particularity.Microbe immobilization is a rising biotechnology.In contrast with traditional microbioremediation,it has the advantage of high biodensity and toxity-resistance.In accordance with oil pollution in surface water's character of large area and low concentration,microbe immobilization has special technical advantage and applied prospect.

Various methods to minimize the physical damages and contamination levels of grain are discussed.The influence of using equipments correctly is analyzed on quality control of grain.

16 strains of nitrosobacteria were isolated from activated sludge and 2 of them with higher nitrite nitrogen accumulation rate were screened,named Y8 and Y16.Y8 was primarily identified as Nitrosococcus sp.and Y16 Nitrosomonas sp..Their growing curves were determined.The activities of nitrosobacteria were examined with the removal rate of ammonia nitrogen or the mass concentration of nitrite nitrogen.The relationships between the mass concentration of nitrite nitrogen and cultivation time,the activities of nitrosobacteria and cultivation temperature,the activities of nitrosobacteria and pH of culture medium were investigated.The ammonia nitrogen removal rate of Y8 and Y16 strains are 81.12% and 75.36% respectively after 5 d of cultivation under the conditions of 30 ℃,medium pH 7.5 and shaking rate 130 r/min.

Traditional remediation technologies for N-contaminated surface water are difficult to be implemented because of its particularity.In this paper the excellences of microbe immobilization remediation technology and its application in N-contaminated surface water are introduced and summarized systemically.And the problems to be resolved and development of future research are also elucidated.

At present,the method to design the pipeline in power plants in China and abroad are different.In China,the version of the ex-Soviet Union was used for many years.But it proved not very rational in practice.After many designing methods have been proposed many times,the method now widely used in China is offered.It is a method like this: the pressure is mostly born by the cross stiffening ribs,and a part of the pressure is taken on by the inside fit bear.The plate of the pipes is computed as a thin plank with large plastic deflection.In this article,the rationality of this method was checked using the software ANSYS.The finite element method were used to check the rationality of the method mentioned above.

多孔管广泛用于喷灌和微灌等节水灌溉工程.在满足多孔管允许压力差的条件下,采用变径设计,即整条多孔管由若干种标准管径的管道组成,可降低多孔管投资.该文建立了各种地形坡度条件下多孔管优化设计数学模型.在应用遗传算法求解优化设计模型中,采用符号编码方法,具有简单、易用的特点.

Analyzing the problems found in the processes of molding, mold filling and solidification of vacuum casting technology, the current technological conditions of V-process. EPC-V, vacuum suction casting, vacuum low-pressure casting and vacuum differential pressure casting are reviewed and discussed. Taking account of different trends in the RD of vacuum casting technology in both China and other countries, the vacuum investment-suction casting process is emphasized to discuss with its advantages and RD trend involved in.

通过对新时期新疆农业节水建设投入主体和受益主体的分析研究,阐述了强制性节水和效益型节水建设两个机制的建立以及农业节水建设的政策保障体系、管理体系、工程体系和技术支持体系四大体系的构建,并对当前农业节水工作的几个误区进行了讨论.