基于非负矩阵分解的水量分配方案后评价

提出了水量分配方案后评价指标体系,建立了基于非负矩阵分解的水量分配方案后评价模型,并以1983年国务院批复的引滦水量分配方案为研究对象进行了水量分配方案诊断式后评价。该方法利用非负矩阵分解算法将指标矩阵最大程度分解为基向量和权向量,根据权向量元素的数值对水量分配方案进行评级,根据基向量元素的数值判断评价指标的实施状况。通过对引滦水量分配方案质量、实施过程、实施效果和可持续性的调查分析,得出方案综合后评价结果为优,但在来用水可持续性、对水环境影响及水质目标保证率等方面需加以改进。评价结果表明,基于非负矩阵分解原理的后评价方法评价效果较好,可为水量分配方案等项目的后评价提供科学依据。     

流化床二组分混合物的适宜分离气速

在等密度与非等密度二组分混合物分离体系中，考察操作气速对分离度的影响，提出物料的静床高对高效分离气速没有影响，而操作气速取其混合物最小流化速度的１．２倍左右时，二组分混合物产生高效分离，并且此操作气速随着二组分混合物分离状态的判定值（等密度混合物指Ｒｍｆ值，非等密度混合物主要指Ｒｐ值）的增加而拓宽。     

川中丘陵区地表干湿长程相关性及影响因素研究（研究生论坛）

为探究川中丘陵区干湿动态动力学机制,提供旱涝预测的理论依据。根据川中丘陵区8个气象站点1958~2013年逐日气象资料,采用Penman—Monteith 模型计算潜在蒸散量,构建出湿润指数。在此基础上,基于去趋势波动分析方法（DFA）,对逐月、分季节、极端干湿湿润指数进行长程相关性分析,并探讨了影响湿润指数长程相关性的气象因子。结果表明：除南充、遂宁外,其余地区逐月湿润指数变化长程相关,并非完全随机;分季节与极端干湿湿润指数均具有长程相关性;对于不同季节而言,长程相关性以夏季最强,秋、冬两季次之,春季最弱,对于极端气候而言,极端湿润长程相关性强于极端干旱;通过对湿润指数与气象因子长程相关性一致性分析,降水标度指数与湿润指数标度指数呈显著正相关。     

Rheological properties and compatibility of NR/EPDM and NR/brominated EPDM blends

Ethylene–propylene–diene terpolymer (EPDM) was modified by bromination reaction. Blending the resulting brominated EPDM with natural rubber (STR5L) and blending the unmodified EPDM with STR5L at various compositions were carried out. The rheological properties of the blends were investigated using a capillary extrusion. Shear flow curves of the pure rubbers and their blends illustrated the pseudoplastic property as shear thinning behavior with a power law index n < 1. True shear viscosity of all blends showed the negative deviation in relation to their additive values. Rheological behavior and two T_g's found from the DSC thermograms at all blend compositions indicated blend incompatibility for both sets of blends. The incompatibility of the vulcanized blends was also found by measuring the spin–spin relaxation time T₂ by pulsed NMR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 837–847, 2003     

空间资源索引与top-k查询研究

以空间资源索引结构R-tree为基础, 考虑人们对空间资源能力指标的要求, 利用道路网络模型进行空间距离的计算, 提出了一种包含能力维度信息的空间资源索引结构和top-k查询算法, 并与传统遍历算法进行对比实验, 验证了查询算法的有效性。     

Structure of Atomic and Molecular Adsorbates on Low-Miller-Index ZnO Surfaces Using X-ray Absorption Spectroscopy

We review our X-ray absorption spectroscopy studies of adsorbate geometries on the O-terminated (000 ) and Zn-terminated (0001) basel faces, as well as the non-polar (10 0) prism face of ZnO. Studies employing near-edge X-ray absorption fine-structure (NEXAFS) and surface X-ray absorption fine-structure (SEXAFS) are included.     

一种具有强实时性、强鲁棒性的图像匹配算法

针对描述符BRIEF对图像旋转敏感的问题,提出一种改进的描述符RIBRIEF,该描述符具有识别能力强、提取速度快、占用空间小及抗干扰能力强等优点,并具有旋转不变性.经分析,图像匹配算法的实时性较大程度上由特征点数量、匹配点搜索次数及描述符相似度计算复杂度决定,因此提出通过描述符索引与描述符聚类相结合、基于FAST稳定特征点提取和逻辑运算计算相似度等方法提高算法的整体实时性.实验结果表明,与描述符BRIEF及SURF相比较,基于描述符RIBRIEF的图像匹配算法在鲁棒性及实时性方面均具有明显优势.     

Efficient Data Access for Location-Dependent Spatial Queries

When the mobile environment consists of light-weight devices, the loss of network connectivity and scarce resources, e.g., low battery power and limited memory, become primary issues of concern in order to efficiently support portable wireless devices. In this paper, we propose an index-based peer-to-peer data access method that uses a new Hierarchical Location-Based Sequential （HLBS） index. We then propose a novel distributed Nearest First Broadcast （NFB） algorithm. Both HLBS and NFB are specifically designed for mobile peer-to-peer service in wireless broadcast environments. The system has a lower response time, because the client only contacts a qualified service provider by accessing the HLBS and quickly retrieves the data to answer the query by using NFB. HLBS and NFB design the index for spatial objects according to the positions of individual clients and transfer the index in the order arranged so that the spatial query can be processed even after the user tunes the partial index. Hence, this design can support rapid and energy-efficient service. A performance evaluation is conducted to compare the proposed algorithms with algorithms based on R-tree and Hilbert-curve air indexes. The results show that the proposed data dissemination algorithm with the HLBS index is scalable and energy efficient in both range queries and nearest neighbor queries.     

A discussion of the methods for comparing the relative effectiveness of phosphate fertilizers varying in solubility

Because various phosphate (P) fertilizers differ widely in their solubility, it is commonly observed that crop response to P fertilizers varies under the same soil and crop conditions. Furthermore, a major problem encountered in the methods for determining the relative effectiveness (RE) of water-insoluble P fertilizer (e.g., phosphate rock) with respect to water-soluble P fertilizers, e.g., single superphosphate (SSP) and triple superphosphate (TSP), is that their growth response curves are usually nonlinear and often do not share a common maximum yield. In this paper, we review and discuss the advantages and disadvantages of the three most commonly used methods for calculating the RE of phosphate rock with respect to TSP (or SSP). The three methods are vertical comparison, horizontal (substitution rate) comparison, and linear-response comparison.     

型腔体组件装配尺寸检测技术分析与运用

为解决型腔体组件装配尺寸的检测问题,以某枪型的型腔体组件为例,分析该型腔体组件的结构特点,设计组合型检测装置,实现准确检测目的.归纳总结了型腔体组件装配尺寸检测技术运用过程中检测装置的设计要领,采用设计与被测型腔体组件相匹配的组合型检测装置,有效解决了型腔体组件装配尺寸检测过程中的定位困难、操作繁琐、检测准确性差等问题.该检测技术对确保型腔体组件装配尺寸的检测稳定性、检测可操作性、检测准确性等方面具有现实的指导意义.