用人工神经网络作地质数据分析

本文提出了利用人工神经网络进行地质数据多变量分析的方法，研究表明，此方法具有精度高、运算速度快、算法简单易于编程等显著特点，是地质数据分析中一有效方法。     

波导短程透镜球差特性分析及其焦距精确测量方法的研究

本文研究短程透镜的焦点位于端面外的球差特性。对焦点位于波导外部（包括端面）的情况给出了一种精确测量焦距新方法，采用这种方法简单易行，测量精度取决于读数显微镜的读数精度（０．０１ｍｍ）。     

New Environment-Friendly Approach for Bastnasite Metallurgic Treatment (I): Extraction of Tetravalent Cerium from Sulphuric Acid Medium with Di(2-ethylhexyl) Phosphoric Acid

Bastnasiteisamainsourceofrareearthproducts inwhichCeO2/REOisabout50%.Atpresent,a cidity leachingcombinedwithalkali conversion method[1]iscommonlyusedinthebastnasitetreat ment.Thismethodisunfriendlytotheenvironment becausetheradioactiveelementofthoriuman…     

人工神经元网络测井解释软件系统

王大力，何清源．人工神经元网络测井解释软件系统．测井技术，１９９４，１８（４）：２５７～２６４在复杂岩性地层的测井解释中，常规的方法常把岩石的矿物成分设想得比较简单，评价地层岩性时需要大量的人工分析。本文提出运用人工神经元网络理论的测井解释软件系统。系统用自然伽玛能谱测井，结合实验室资料可准确确定粘土类型和求出粘土含量。选用了一种稳定性好、快速的优化算法，使用孔隙度测井资料求出孔隙度值，整个系统算法上力求快准、解释上力求尽可能减少人工干预，该软件系统经试用效果较好。     

A simple fiber-optic vehicle axle detector for roadways

This paper presents a fiber-optic vehicle axle detector for roadways. It is based on a fiber-optic Michelson interferometer that is mounted directly into the road surface. The fully dielectric design allows for remote operation of the sensor via a long section of optical fiber. A simple signal-processing scheme of the output signals has been adopted that allows for reliable detection of commercial and personal vehicles.     

崇拜与征服──试论两性服装

男装和女装的区分，从根本上说，源于人类两性社会学意义上的分离，男女装的形成与发展，从一个侧面反映了人类文明进程中性别尊卑这一社会伦理观念的演化，成为一系列服装文化现象诸如服饰动机、审美标准的依据。并在普遍的意义上，揭示了服装观念的基本原则和规律．     

Preparation of Whisker β-Spodumene Glass–Ceramics

β-spodumene glass–ceramics with a whisker-like microstructure were prepared from the following materials (in wt%): 64.5 SiO₂, 18.0 Al₂O₃, 4.2 Li₂O, 4 ZrO₂, and 8 MgF₂. Scanning electron microscope (SEM) analysis showed that phase separation in the base glass leads to the formation of a primary crystal phase of MgF₂ that promotes the formation of spherical β-spodumene. Whisker spodumene crystals surrounded by spherical crystals are observed at 720°C after 1 h, and the whisker crystals grow at the cost of spherical crystals with increasing temperature and time. The flexural strengths of the glass–ceramics reach a maximum of 228 MPa after heat treatment at 850°C for 1 h.     

Why Phenolic Acids Are Unlikely Primary Allelochemicals in Rice

Allelopathy in rice (Oryza sativa, L.) effective against weeds has been found in about 3.5% of tested rice germplasm in both laboratory and field experimentation. However, the allelochemicals responsible for growth inhibition of rice-associated weeds have not yet been identified. In the literature, phenolic acids are often mentioned as putative allelochemicals. If phenolic acids commonly reach growth inhibitory concentrations in rice ecosystems, it must be expected that the degree of tolerance to phenolic acids will vary among traditional rice cultivars or plant species adapted to rice environments having inherently different phenolic acid concentrations. Phenolic acids concentrations are normally greater in submerged than in aerobic soils. A dose–response study, however, showed that seedlings of rice cultivars adapted to submerged anaerobic soils did not have higher level of tolerance against p-hydroxybenzoic acid than did seedlings of varieties adapted to aerobic upland soils. Moreover, traditional rice cultivars had no greater tolerance than did improved cultivars that were recently bred for traits other than tolerance of phenolic acids. Similarly, there were no differences in tolerance of p-hydroxybenzoic acid between two Echinochloa weed species adapted to either anaerobic or aerobic growth conditions. Thus, neither the rice cultivars nor weed species had evolved different tolerance levels against the phenolic acid. However, all rice cultivars had significantly greater tolerance of p-hydroxybenzoic acid than did either weed species. In a second experiment, the rates at which rice plants released phenolic acids into solution cultures were measured for at least one month, the time period of greatest allelopathic activity following planting under field conditions. The maximum release rate of phenolic acids during the first month of growth was approximately 10 g/plant/day. At a conventional plant density, the release rate of phenolic acids would be approximately 1 mg/m²day. This order of release rate cannot provide concentrations remotely close to phytotoxic levels determined for these rice cultivars and weed species. The results presented in this paper do not preclude the possibility that phenolic acids might be one component in a mixture of chemicals that, when present simultaneously, are allelopathic.     

腐蚀预应力钢绞线的疲劳试验分析

为了研究钢绞线腐蚀后的疲劳性能,采用通电加速腐蚀方法制作了包括5根无腐蚀与22根腐蚀预应力钢绞线试件,并通过轴向拉伸疲劳试验对预应力钢绞线腐蚀后的疲劳性能退化规律进行了研究分析,试验主要考察了腐蚀率与应力水平对钢绞线疲劳寿命的影响。试验结果表明,腐蚀后的钢绞线疲劳寿命显著降低,腐蚀钢绞线的名义应力幅与疲劳寿命在双对数坐标系下仍近似符合线性关系,同级荷载水平下的钢绞线疲劳寿命随腐蚀率的增长按指数函数衰减。此外,本文根据试验结果还建立了腐蚀钢绞线的疲劳曲面方程,并给出了不同保证率下的腐蚀钢绞线疲劳强度建议值。     

基于VSC-MTDC的风电场并网控制策略研究

针对风电具有随机性与间歇性等特点,本文提出适用于风电场经多端柔性直流输电系统（voltage source converter-multi-terminal direct current , VSC-MTDC）并网时的多点直流电压自适应斜率控制策略。该控制策略将稳定直流电压的任务分配给多个具备功率调节能力的换流站,换流站之间不需要通信,根据自身的功率裕度自适应调节所承担风电功率变化量的大小,合理的利用多端系统的调节容量,同时避免换流站在按照固定直流电压-有功功率斜率运行时容易引起过载运行的情况。最后利用 PSCAD/EMTDC 针对该控制方式进行仿真分析,结果表明这种控制方式比较适合应用于潮流频繁变化的风电场VSC-MTDC系统。