纳安线杂散电流腐蚀检测与防护

川渝地区部分输气管道受到较严重的杂散电流干扰腐蚀,本文以纳安线为研究对象,对其进行了杂散电流干扰检测,并根据检测结果提出了相应的腐蚀防护方案。

科技为先 质量为本——山西送变电公司创建托安线精品工程纪实

山西送变电公司中标承建的托安(内蒙托克托--北京安定)500干伏双回输电线路第三标段全长132公里、杆塔291基-途径山西右玉、左云、怀仁三县.为了把托安线建成华北地区的一流工程,该公司克服工期紧、任务重、大面积跨越林区和地形条件复杂等实际困难,坚持以"科技为先、质量为本"的方针,在"不停电跨越施工"、"改善跳线安装工艺"和"提高放线速度"等方面取得了新成果和新突破,确保了整个工程高质量、如期投入运行,被华北电力集团公司评为托安线质量优胜单位(第三名).

The Chinese Herbal Formula Weichang’an Reduces the Proliferation of Human Gastric Cancer Cells via Mitochondrial Apoptosis

Objective The aim of the study was to investigate the effects of Chinese herbal formula Weichang’an(WCA)on the proliferation and mitochondria-mediated apoptosis of human gastric cancer cells.Methods Cell Counting Kit-8(CCK8)was used to evaluate the antiproliferative activity ofWCA on MKN45 cells;Giemsa staining was used to investigate cell colony formation;flow cytometry was used to analyze cell cycle,apoptosis rate,and caspases activation;and Hoechst staining was used to analyze the morphology of cell nuclei.The mitochondrial membrane potential was analyzed by both flow cytometric measurements and fluorescence microscopy.Western blot was used to analyze the protein levels of pro-caspase-3,Bcl-2,Bax,and Bcl-X.MKN45 cells were subcutaneously injected into the right forelimb of 16 nude mice to establish the tumor xenograft model,and a total of 12 nude mouse tumor xenograft models were successfully created.The nude mice were divided into the control group and the WCA-treated group.The two groups received normal saline and WCA treatment at 35.49 g/kg by a single daily oral gavage for 21 days.The body weight and tumor size of the nude mice were measured twice a week.The ultrastructural changes of subcutaneous tumors were observed by a transmission electron microscope.Results WCA can suppress cell proliferation and colony formation.It can also induce changes in the mitochondrial membrane potential and increase the activities of caspases-3,caspases-8,and caspases-9 in MKN45 cells.WCA induced S-phase arrest and apoptosis in MKN45 cells,and decreased the expression levels of antiapoptotic proteins Bcl-2 and Bcl-X in MKN45 cells,while increasing the expression levels of the proapoptotic proteins Bax and pro-caspase-3 compared with the control group.WCA inhibited the growth of a xenografted MKN45 tumor in nude mice,and the protein levels of Bax and pro-caspase-3 were significantly increased,while Bcl-X and Bcl-2 were reduced compared with the control group.The differences are statistically significant(p<0.05).Conclusion WCA could suppress the proliferation of gastric cancer cells via mitochondrial apoptosis.

In-situ measurement and distribution of flue gas mercury for a utility PC boiler system

The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.

Investigation of Heavy Metal Contents in Traditional Chinese Herbal Medicine Peristrophe roxburghiana Collected from Northwest of Guangxi

Objective] This study was conducted to evaluate the product quality and safety of Peristrophe roxburghiana_ col ected from different places in Hechi City, northwest of Gunagxi, so as to provide basic data for further development and uti-lization of the characteristic plant resource P. roxburghiana. [Method] Contents of 9 kinds of heavy metals including Cd, Mn, Pb, Zn and Cu in the herb were deter-mined by the method of wet digestion-flame atomic absorption spectrophotometry and atomic fluorescence spectrometry, respectively. [Results] Heavy metal contents of Cd, Mn, Pb, Fe, Cu, Zn, As, Hg and Se were 1.62-17.25, 8.93-142.53, 4.37-18.43, 103.7-242.81, 2.55-5.35, 85.40-146.30, 0.07-0.54, 0.00-0.08 and 0.00-0.47 mg/kg, respectively. According to the national food safety standards and Green Trade Standards of lmporting ＆amp; Exporting Medicinal plants ＆amp; Preparations, the heavy metal contents of the P. roxburghiana_samples col ected from different coun-ties in Hechi City exceeded standards or at the critical values. Among which, Cd, Pb and Zn contents of the samples are seriously higher than the standards. [Con-clusion] Therefore, the impact of soil heavy metal pol ution on the safety of edible plants in the northwest of Guangxi should be highly concerned.

广义Viviani曲线

在教学中,培养学生的运用能力,特别是综合运用能力是非常重要的。在《解析几何》(江苏师范学院84年版)中,求Viviani(维维安尼)曲线(以下简称维安线)的一般方程和参数方程,就是一个研究空间曲线的很好的练习。我认为,在求出其方程后。

Installation and Debugging of Auto-control System in Fruit Wine Production Line

[Objective] The aim was to test the controlling effect of cleaning steriliza- tion system, material conveying system, and fermentation jar cooling system with equip- ments of fruit wine production line introduced in this study and its auto-control sys- tem field assembled and debugged. [Method] Based on controlling equipment and setting parameters on the configuration interface, the operation state of the control equipments could be real-time monitored and controlled with the help of configura- tion software. [Result] The result showed that the equipment system could reduce the temperature into 12 ℃ with the error of ＋0.5 ℃within 110 minutes when the fermentation temperature is set at 12 ℃ in real production. [Conclusion] The auto- control system of fruit wine production line was easy to be assembled and de- bugged to meet demands of different fruit wine productions.

Effects of polyaniline on electrochemical properties of composite inert anodes used in zinc electrowinning

In order to search for a suitable anode material used in zinc electrowinning in place of Pb-Ag alloy,Al/Pb-PANI（polyaniline）-WC（tungsten carbide） composite inert anodes were prepared on aluminum alloy substrate by double pulse electrodeposition（DPE） of PANI and WC particles with Pb2＋ from an original plating bath.Thereafter,anodic polarization curves,cyclic voltammetry curves and Tafel polarization curves for the composite inert anodes obtained under different PANI concentrations in the original plating bath were measured,and the microstructural features were also investigated by scanning electron microscopy（SEM）.The results show that Al/Pb-PANI-WC composite inert anode obtained under PANI concentration of 20 g/L in the original plating bath possesses uniform microstructures and composition distributions,higher electrocatalytic activity,better reversibility of electrode reaction and corrosion resistance in a synthetic zinc electrowinning electrolyte of 50 g/L Zn2＋,150 g/L H2SO4 at 35 °C.Compared with Pb-1%Ag alloy,the overpotential of oxygen evolutions for the composite inert anode are decreased by 185 mV and 166 mV,respectively,under 500 A/m2 and 1000 A/m2.

Nonlinear Current-Voltage Characteristics and Electroluminescence of cBN Crystal

The current-voltage（I-V） characteristics of cBN crystal sandwiched between two metallic electrodes are measured and found to be nonlinear. Over 20 samples are measured at room temperature with various electrodes, and the resulting curves are all similar in shape. When a voltage of about 560V is applied to the cBN crystal, the emitted light is visible to the naked eye in a dark room. We explain these phenomena by the space charge limited current and the electronic transition between the X and Г valleys of the conduction band.

Direct Synthesis of High Purity Silicon Wires by Electrorefining in Molten KF-NaF Eutectic

The electrochemical synthesis silicon wires by electrorefining metallurgical grade silicon in thermally dried and pre-electrolyzed molten KF-NaF eutectic were studied at temperatures 800-900 ℃ using cyclic voltammetry and ac impedance. One oxidation peak at -0.14 V could be attributed to the reaction of Si to Si4＋. A cathodic peak occurred at -0.56 V in the cyclic voltammogram and one response semicircle in the ac impedance spectrum was observed, supporting a one-step electrochemical reduction process of Si4＋-→Si. The electrochemical reaction of silicon was controlled by the diffusion process. The purity of electrorefined silicon wires was up to 99.999% by ICP-MS analysis.

好太王的陵墓再确认及相关问题

根据墓葬类型结构和遗物特征,尤其是铭砖和刻铭铜铃的出土,充分证明"太王陵"是好太王的陵墓,由此也推定出"将军坟"是长寿王的陵墓。集安麻线新出高句丽碑碑文中的"国罡上太王",是好太王的谥号,因此该碑建于好太王之后。碑文所记"以此河流四时祭祀",将山川崇拜和祖先祭祀相结合,祭祀的祖先是建碑之前以邹牟王为首的诸位祖先王。

Singular Perturbations for a Class of Fourth-order Nonlinear Boundary Value Problem

This paper is devoted to study the following the singularly perturbed fourth-order ordinary differential equation ∈y（4） =f（t,y＇,y＇＇,y＇＇＇）,0t1,0ε1 with the nonlinear boundary conditions y（0）=y＇（1）=0,p（y＇＇（0）,y＇＇＇（0））=0,q（y＇＇（1）,y＇＇＇（1））=0 where f：[0,1]×R3→R is continuous,p,q：R2→R are continuous.Under certain conditions,by introducing an appropriate stretching transformation and constructing boundary layer corrective terms,an asymptotic expansion for the solution of the problem is obtained.And then the uniformly validity of solution is proved by using the differential inequalities.

考虑输电线路安全的机械除冰次序优化

机械除冰是应对输电线路覆冰灾害的重要手段,现有研究主要集中在除冰方法的改进,而对机械除冰实施过程的影响研究较少。研究发现在机械除冰过程中,如果按照从输电线路一端开始顺序除冰的策略,杆塔承受的最大不平衡力可能超过设计标准,影响输电线路安全,而不同的除冰次序会产生不同的最大不平衡力。为此,有必要对机械除冰的除冰次序进行优化,提高机械除冰的安全性。首先分析了机械除冰过程中除冰次序对杆塔平衡力的影响,然后建立了输电线路机械除冰次序优化模型。由于该模型为非线性、多约束模型,采用遗传算法对不同档导线覆冰清除的次序进行优化。仿真分析表明,优化后的除冰次序能够有效地降低杆塔承受不平衡力,提高机械除冰过程中输电线路的安全性。

Semi on-line scheduling for maximizing the minimum machine completion time on three uniform machines

The paper investigates a semi on-line scheduling problem wherein the largest processing time of jobs done by three uniform machines M1, M2, M3 is known in advance. A speed si (s1=1, s2=r, s3=s, 1≤r≤s) is associated with machine Mi. Our goal is to maximize Cmin?the minimum workload of the three machines. We present a min3 algorithm and prove its competitive ratio is max{r+1,(3s+r+1)/(1+r+s)}, with the lower bound being at least max{2,r}. We also claim the competitive ratio of min3 algo- rithm cannot be improved and is the best possible for 1≤s≤2, r=1.

Performance of beacon safety message dissemination in Vehicular Ad hoc NETworks (VANETs)

Currently, there is a growing belief that putting an IEEE 802.11-like radio into road vehicles can help the drivers to travel more safely. Message dissemination protocols are primordial for safety vehicular applications. There are two types of safety messages which may be exchanged between vehicles: alarm and beacon. In this paper we investigate the feasibility of deploying safety applications based on beacon message dissemination through extensive simulation study and pay special attention to the safety requirements. Vehicles are supposed to issue these messages periodically to announce to other vehicles their current situation and use received messages for preventing possible unsafe situations. We evaluate the performance of a single-hop dissemination protocol while taking into account the quality of service (QoS) metrics like delivery rate and delay. We realize that reliability is the main concern in beacon message dissemination. Thus, a new metric named effective range is defined which gives us more accurate facility for evaluating QoS in safety applications specifically. Then, in order to improve the performance, the effects of three parameters including vehicle's transmission range, message transmission's interval time and message payload size are studied. Due to special characteristics of the safety applications, we model the relationship between communication-level QoS and application-level QoS and evaluate them for different classes of safety applications. As a conclusion, the current technology of IEEE 802.11 MAC layer has still some challenges for automatic safety applications but it can provide acceptable QoS to driver assistance safety applications.

The Information Modeling and Intelligent Optimization Method for Logistics Vehicle Routing and Scheduling with Multi-objective and Multi-constraint

The vehicle routing and scheduling (VRS) problem with multi-objective and multi-constraint is analyzed, considering the complexity of the modern logistics in city economy and daily life based on the system engineering. The objective and constraint includes loading, the dispatch and arrival time, transportation conditions,total cost,etc. An information model and a mathematical model are built,and a method based on knowledge and biologic immunity is put forward for optimizing and evaluating the programs dimensions in vehicle routing and scheduling with multi-objective and multi-constraints. The proposed model and method are illustrated in a case study concerning a transport network, and the result shows that more optimization solutions can be easily obtained and the method is efficient and feasible. Comparing with the standard GA and the standard GA without time constraint,the computational time of the algorithm is less in this paper. And the probability of gaining optimal solution is bigger and the result is better under the condition of multi-constraint.

Improved Feistel-based ciphers for wireless sensor network security

Wireless sensor networks (WSNs) are exposed to a variety of attacks. The quality and complexity of attacks are rising day by day. The proposed work aims at showing how the complexity of modern attacks is growing accordingly, leading to a similar rise in methods of resistance. Limitations in computational and battery power in sensor nodes are constraints on the diversity of security mechanisms. We must apply only suitable mechanisms to WSN where our approach was motivated by the application of an improved Feistel scheme. The modified accelerated-cipher design uses data-dependent permutations, and can be used for fast hardware, firmware, software and WSN encryption systems. The approach presented showed that ciphers using this approach are less likely to suffer intrusion of differential cryptanalysis than currently used popular WSN ciphers like DES, Camellia and so on.

Secure Authentication of WLAN Based on Elliptic Curve Cryptosystem

The security of wireless local area network （WI.AN） becomes a bottleneck for its further applications. At present, many standard organizations and manufacturers of WLAN try to solve this problem. However, owing to the serious secure leak in IEEES02.11 standards, it is impossible to utterly solve the problem by simply adding some remedies. Based on the analysis on the security mechanism of WLAN and the latest techniques of WI.AN security, a solution to WLAN security was presented. The solution makes preparation for the further combination of WLAN and Internet.

Study on RFID Authentication Protocol Theory

Secure and private authentication protocol is important in Radio Frequency Identification (RFID) technology.To date,researchers have proposed many RFID authentication protocols.However,these protocols have many flaws due to lack of theoretical support in designing these protocols.In this work,first we present the security and privacy requirements in RFID authentication protocols.Then we examine related works and point out problems in designing RFID authentication protocols.To solve these problems,we propose and briefly prove three theorems.We also give necessary examples for better understanding these theorems with concrete protocols.At last,we give our suggestions on designing secure and private authentication protocols.The security and privacy requirements,theorems,and suggestions will facilitate better understanding and designing of RFID authentication protocols in the future.

On-line least squares support vector machine algorithm in gas prediction

Traditional coal mine safety prediction methods are off-line and do not have dynamic prediction functions.The Support Vector Machine(SVM) is a new machine learning algorithm that has excellent properties.The least squares support vector machine(LS-SVM) algorithm is an improved algorithm of SVM.But the common LS-SVM algorithm,used directly in safety predictions,has some problems.We have first studied gas prediction problems and the basic theory of LS-SVM.Given these problems,we have investigated the affect of the time factor about safety prediction and present an on-line prediction algorithm,based on LS-SVM.Finally,given our observed data,we used the on-line algorithm to predict gas emissions and used other related algorithm to compare its performance.The simulation results have verified the validity of the new algorithm.