再论东庄水库的岩溶渗漏问题

东庄水库工程勘察设计论证工作几起几落,都因岩溶渗漏问题而停滞,历经4年再次勘察试验研究,进一步论证了东庄水库碳酸盐岩库段不发育古岩溶。泾河形成于1.4 MaB.P,区域性地壳抬升速率达1.55 mm/年,新岩溶发育轻微。同时由于受老龙山断裂和沙坡断层制约,岩溶发育深度有限,其发育规律主要受构造、风化卸荷作用控制,两岸分水岭地段深岩溶不发育,地下水位接近或高于水库正常蓄水位,而且20世纪60年代还是地下水补给河水,库坝段形成悬托河时间短,岩体渗透性微弱,水库淤积防渗功能显著,水库渗漏量小,在坝区采取常规防渗处理,即可把渗漏控制在允许范围内。     

SAR实时成像高效矩阵转置研究和实现

矩阵转置是SAR成像处理中的重要运算,SAR成像的实时巨量数据处理对基于片外存储的矩阵转置算法效率提出了很高的要求,而目前的实时转置算法实现的效率都偏低.文中通过分析片外存储特性,研究和提出适用于SAR实时成像的矩阵转置算法,占有片内资源少,读写平衡且效率高,配置灵活可组合成较复杂的矩阵转置形式,目前已成功应用于多种模式的SAR成像处理.     

改性磷石膏抹灰砂浆性能研究

为了解决磷石膏抹灰砂浆耐水性差的问题,促进磷石膏抹灰砂浆在建筑行业的应用,采用预处理的改性磷石膏,研究了水胶比和减水剂掺量对改性磷石基抹灰砂浆物理性能、力学性能和耐水性能的影响,并通过在体系中引入有机硅防水剂来进一步改善磷石膏抹灰砂浆耐水性能。研究结果表明:减水剂掺量和水胶比是影响磷石膏抹灰砂浆性能的主要因素,低水胶比和低减水剂掺量有利于其力学性能和耐水性能的提升,且减水剂掺量不宜高于0.9%;有机硅防水剂虽然能有效改善磷石膏抹灰砂浆耐水性能,但会对其强度造成不利影响,实际应用时其掺量不宜高于0.6%;水化产物中的凝胶和钙矾石可以填充二水硫酸钙晶体间空隙,有利于试件密实度、强度和软化系数的提高,且有机硅防水剂会在水化产物表面和间隙中形成防水膜,可以进一步改善试件耐水性能。     

地聚合物凝胶体系中N-A-S-H和C-A-S-H结构的分子模拟

钙元素对地聚合物凝胶结构的形成影响显著,根据含钙量的不同可分为高钙体系(C-A-S-H)和无钙体系(N-A-S-H).基于Materials Studio软件,用Amorphous Cell(AC)模块构建了N-A-S-H和C-A-S-H凝胶结构模型.在Universal力场下,对2个凝胶结构模型的稳定性、动力学轨迹、微观表征及弹性模量进行了分子动力学模拟.结果表明,构建的N-A-S-H和C-A-S-H凝胶结构模拟值与试验值吻合较好.由于钙元素的存在,无定形态体系出现了向晶体转变的特征,并对地聚合物的力学性能产生正向增益.     

户部寨气田涡流排水采气技术先导试验

户部寨气田目前已处于开发后期阶段,多数气井的压力及产量难以满足临界携液要求,井筒积液较为普遍,制约了气井产能的发挥。针对增压气举、优选管柱等常规排水采气工艺存在的技术局限,综合考虑涡流工具适用条件及气田开发实际,优选部1-9井开展了涡流排水采气先导试验,现场试验结果表明:该井加装涡流工具后携液能力较先前明显提升,相同注气条件下日产液量提高91%,同时增大生产压差约1 MPa,取得了较好的试验效果,可为同类气井排液对策制订提供相应技术借鉴。     

一种光伏用高升压比高效率直流变换器

以光伏为代表的新能源发电日益受到重视。为提高光伏发电系统的可靠性与发电效率,两级式光伏并网发电系统的前级DC/DC变换器对升压比和效率提出了要求。首先对FIBC拓扑的工作原理、高升压性能、低电力电子器件应力等进行详细分析,与传统Boost电路的对比结果验证了FIBC的优越性;然后建立了Boost和FIBC电路的损耗模型,给出了额定工况下的损耗分布和效率,结果表明同电路参数下FIBC具有更高的效率;接着利用交错控制技术,对FIBC电感参数进行了优化,进一步提高变换器效率;最后给出Boost与FIBC和优化FIBC在不同工作电流下的效率曲线,结果表明优化后FIBC效率提高明显,比Boost更适合用于低压大功率光伏发电系统中。基于Matlab/Simulink平台的仿真结果表明,使用交错技术可以优化电感参数,直流母线输出电压能够稳定在400 V。     

Tribo-corrosion behaviors of Ti3SiC2/Si3N4 tribo-pair in hydrochloric acid and sodium hydroxide solutions

This paper is a continuation of our work to characterize the tribo-corrosion behaviors of Ti₃SiC₂ in common acids and alkalis [Ren et al. (2010) [1]]. Tribo-corrosion behaviors of Ti₃SiC₂/Si₃N₄ in hydrochloric acid (HCl) and sodium hydroxide (NaOH) with different concentrations were investigated in the present paper. The worn surfaces of Ti₃SiC₂ and Si₃N₄ were examined using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that oxide films form on the worn surfaces of both Ti₃SiC₂ and Si₃N₄ by corrosive oxidation and/or tribo-oxidation. The SiO₂ film, however, does not effectively prevent grains from detaching. Mechanical wear dominates the friction process rather than chemically corrosive wear for Ti₃SiC₂. Chemically corrosive reactions, in turn, decelerate mechanical wear to a certain extent. Corrosive wear resulting from oxidation and dissolution of material by corrosive solutions and mechanical wear from abrasion contribute to material loss for Si₃N₄. The high viscosity of NaOH solutions decreases friction and wear.     

Structure and Micromorphology of Wear Debris of MC Nylon 6 under Dry Sliding: Correlation with Wear Mechanisms

The structure and micromorphology of wear debris of MC nylon 6 under dry sliding were investigated by FTIR, XRD, DSC, and FESEM, and the 3D surface topographies of friction materials before and after the friction test were observed, which will be helpful in understanding the friction and wear processes. The primary crystalline phase of both the unworn MC nylon 6 and the wear debris were α crystal, but the crystallinity of the latter was higher than that of the former. The proportion of α ₂ (002 + 202) planes increased and the reflection from the α ₁ (200) planes was suppressed in the wear debris, indicating a preferential arrangement of α ₂ (002 + 202) on the surface of the wear debris. The transition in structure of the wear debris originated from the activation of the chain segments due to the thermodynamic effects. The thermodynamic effects and high chain segment mobility resulted in the hydrogen bonding whose interchain distance is a larger rupture or even chain scission. MC nylon 6 was severely worn due to the contribution of the tearing force that resulted from the combined action of the tribo-interface adhesion and the shearing effect during friction, whereas no damage happened on the worn surface of the counterpart steel pin even if under severe sliding conditions.     

微波预处理压榨茶叶籽油及其氧化稳定性

采用微波预处理压榨法提取茶叶籽油,与烘烤后压榨法在提取率、理化性质和氧化稳定性进行了比较.结果表明,微波预处理压榨茶叶籽油得率比120℃烘烤后压榨得油率高9.6％,为21.81％,油脂提取率为77.5％;微波预处理压榨茶叶籽油的理化性质与60、80℃烘烤后压榨茶叶籽油无明显差异;微波预处理压榨茶叶籽油氧化稳定性高于60℃烘烤后压榨的茶叶籽油,适当升高烘烤温度,压榨茶叶籽油的氧化稳定性升高,当烘烤温度达到120℃时,其氧化稳定性下降.     

Image categorization using a semantic hierarchy model with sparse set of salient regions

Image categorization in massive image database is an important problem. This paper proposes an approach for image categorization, using sparse set of salient semantic information and hierarchy semantic label tree (HSLT) model. First, to provide more critical image semantics, the proposed sparse set of salient regions only at the focuses of visual attention instead of the entire scene was formed by our proposed saliency detection model with incorporating low and high level feature and Shotton’s semantic texton forests (STFs) method. Second, we also propose a new HSLT model in terms of the sparse regional semantic information to automatically build a semantic image hierarchy, which explicitly encodes a general to specific image relationship. And last, we archived image dataset using image hierarchical semantic, which is help to improve the performance of image organizing and browsing. Extension experimental results showed that the use of semantic hierarchies as a hierarchical organizing framework provides a better image annotation and organization, improves the accuracy and reduces human’s effort.