Adaptive detection of range-spread targets without secondary data in multichannel autoregressive process

Adaptive detection of range-spread targets without secondary data is addressed in a multichannel autoregressive Gaussian disturbance with unknown space–time covariance matrix, by utilizing the Rao test. The proposed Rao test without secondary data is theoretically proved to be asymptotically (large-sample in the number of temporal observations) constant false alarm rate with respect to unknown space–time covariance matrix, thanks to an asymptotic equivalence between the Rao test and the generalized likelihood ratio test. Moreover, the performance loss due to no secondary data can be remedied by appropriately increasing the temporal dimension. The performance assessment conducted by Monte Carlo simulation, also in comparison with the existing detector without secondary data, confirms the effectiveness of the proposed detectors.     

灌丛密度对沙粒粒度和起动风速影响研究

选择了位于宁夏中卫市西北角的中国科学院野外风沙观测场风沙工程实验区,采集不同密度灌丛区沙样,通过室内分析及风洞实验,研究了灌丛迎风和背风方向沙粒粒度结构及起动风速特征,得到以下结论:灌丛周围粒度分布曲线属高狭峰偏态分布型,灌丛的存在有利于风蚀中细沙和极细沙的截留;同时灌丛密度大小对于沙粒粒度特征及其起动风速都有重要影响,经文中详细分析,灌丛的最佳防护密度为12%～15%.     

Authentication of the 31 species of toxic and potent Chinese materia medica by microscopic technique assisted by ICP-MS analysis, part 4: four kinds of toxic and potent mineral arsenical CMMs

Toxic and Potent Chinese Materia Medica (T/PCMM) is a special and very important category of Chinese medicines. They have long been used in traditional medical practice and are being used more and more widely throughout the world in recent years. As there may be many fatal toxic effects caused by misusing or confusion of T/PCMM, their quality and safety control arouse increasing attention internationally. Researches on the accurate identification to ensure the safe use of T/PCMM are acquired; however, there are few reports on authentication. We are carrying out a series of studies on 31 T/PCMM originating from plants, animals, minerals, and secreta. In our previous studies, we proved that modern microscopic authentication is a simple, fast, effective, low cost, and less toxic method for identifying animal, seed, and flower T/PCMM. In the present study, we focused on the authentication of four kinds of mineral arsenicals, including orpiment (mainly containing As₂S₃), realgar (mainly containing As₄S₄), arsenolite, and arsenic trioxide (mainly containing As₂O₃). We examined the macroscopic and microscopic characteristics of the above minerals and found that they all can be easily identified and authenticated by using light microscopy coupled with polarized microscopy. Moreover, the authentication results for arsenolite and arsenic trioxide are confirmed by ICP‐MS analysis. We are sure that the morphological and microscopic characteristics indicated here are indispensable to establishing standards for these four mineral T/PCMMs. Microsc. Res. Tech. 74:1‐8, 2011. © 2010 Wiley‐Liss, Inc.     

Effective degradation of para-chloronitrobenzene through a sequential treatment using zero-valent iron reduction and Fenton oxidation

In this study, zero-valent iron (ZVI) was used to pretreat para-chloronitrobenzene (p-CNB), and the major product was para-chloroaniline (p-CAN). By adding H(2)O(2) directly, further p-CAN degradation can be attributed to Fenton oxidation because ferrous ions (Fe(2+)) released during the ZVI corrosion could be used as an activator for H(2)O(2) decomposition. In the reduction process, the reduction efficiency of p-CNB as well as Fe(2+) concentration increased with increasing iron dosage and decreasing solution pH. Under the optimal conditions, 25 mg L(-1) of p-CNB could be transformed in 3 h when initial solution pH was 3.0 and ZVI dosage was 2.0 g L(-1). A sufficient amount of Fe(2+) (50.4 mg L(-1)) was obtained after the above reaction to activate H(2)O(2). In the Fenton process, the oxidization of p-CAN was also more effective in acidic conditions and it increased with increasing H(2)O(2) concentration. The control experiments showed that the sequential treatment was more effective than Fenton oxidation alone in treating p-CNB wastewater since the removal rate of total organic carbon (TOC) was improved by about 34%. It suggested that the amino function group is more susceptible to oxidative radical attack than the nitro function group. Therefore, sequential treatment using zero-valent iron reduction followed by Fenton oxidation is a promising method for p-CNB degradation.     

导水系数的空间变异性对地下水非恒定流计算的影响

在探讨水文地质参数空间变异性的基础上,考虑导水系数为常量及参数随空间变量发生改变的情况下,比较交替方向隐式差分法计算地下水二维非恒定流方程的异同。引入算例分别进行计算与分析,得出水文地质参数的空间变异性对地下水非恒定流计算存在影响的结论,进一步说明水文地质参数空间变异性研究工作的重要性与必要性,并提出今后研究工作的建议方向与重点。     

复杂地质高陡边坡锚索施工实践及若干技术控制标准的探讨

以雅砻江锦屏一级水电站大坝左岸550 m级高陡边坡预应力锚固工程为研究对象,在复杂工程地质条件下进行了超长、高承载力锚索施工实践,就锚索造孔技术、束体安装工艺、注(灌)浆技术、张拉工艺等方面进行研究与总结.然后,对监测资料进行分析评价,形成了一套复杂地质条件下高陡边坡锚索施工的技术与方法.文中还结合水电行业锚固施工规范、锚喷支护国标中的技术控制标准,对施工中存在的技术问题进行探讨,可为同类型高边坡锚固工程施工提供参考和借鉴.     

基于灰色聚类法的大凌河水环境质量综合评价

利用白化权函数描述水质分级,利用平均标准值法进行量纲一化,利用倒数法确定聚类权,建立了大凌河水环境质量灰色评价模型.根据大凌河污染物排放特点选择参评因子,以地表水环境质量标准为评价依据,对大凌河进行水质评价与分析.结果表明:上窝堡的水质等级为Ⅲ级,污染程度为中度;朝阳与义县的水质等级为Ⅳ级,污染程度为重度;凌海的水质等级为V级,污染程度为严重;大凌河部分水域已经不能满足用水要求,需要采取措施控制污染物排放.     

水库移民后期扶持监测评估研究

根据监测评估实践,对水库移民后期扶持监测评估的主要内容、指标体系、调查表格、工作步骤、方法等进行了系统总结。指出:水库移民后期扶持评估内容主要包括扶持政策实施情况,扶持资金的征收、使用和管理情况,扶持政策实施效果等;后期扶持监测评估指标体系由资金发放、项目实施、政策实施保障和政策实施效果4个一级指标构成,下设16个二级指标、40个三级指标;评估方法有统计分析、对比分析、参与式评价和综合评价。     

掺纤维混凝土早期开裂敏感性研究

为了研究混凝土早期的抗裂性能,利用温度应力试验机研究掺不同种类纤维混凝土的开裂敏感性,通过分析各种参数的优劣性,选定开裂温度作为开裂敏感性的评价指标。结果表明,改性聚乙烯醇纤维或聚丙烯纤维的掺入,可以有效降低混凝土的开裂温度,其中掺PVA1纤维的混凝土开裂温度最低,即其抗裂性能最好。与传统的试验方法相比,温度应力试验机能大大减少测试的工作量,是一种值得推广的试验仪器。     

气密性混凝土在松卜岭高瓦斯隧道衬砌中的应用

松卜岭隧道穿越煤岩层,为高瓦斯隧道。为保证隧道的运行安全,在隧道瓦斯设防段须采用气密性混凝土对坑道进行全断面封闭式复合衬砌。通过对隧道穿越的地质环境条件、设计标准、气密性混凝土材料以及合理配合比的选择分析,采用室内试件测定方法对混凝土试件的透气量进行测定,计算得出透气系数。对不同衬砌形式的混凝土的气密性进行了评价,结果表明：气密性混凝土在隧道衬砌中具有明显的抗气性。不仅能在瓦斯隧道衬砌中应用,也可应用于其他有较高防潮、防渗要求的工程中。