金沙江中游梯级水电站联合优化调度实践

分析了金沙江中游区域梯级水电站联合调度的特殊性及复杂性,从电调的角度介绍了金中集控中心自成立以来对受控梯级水电站联合调度的具体实施,总结了梯级水电站联合优化调度的措施,并分析了梯级水电站联合优化调度的综合效益,发现优化调度成效明显。     

Crystal structure and microwave dielectric properties of (Ba1−αSrα)6−3xSm8+2xTi18O54 solid solutions

The tungstenbronze-type-like (Ba_1−αSr_α)_6−3xR_8+2xTi₁₈O₅₄ (R = rare earth) solid solutions have been studied. Microwave dielectric properties of these solid solutions link to the substitution of large cations such as Ba ions by small Sr ions. In these solid solutions for x = 0, the quality factor (Q·f) exibits extremely low due to the inner strain resulting by the occupation of large Ba ions at relatively small A1-sites. However, dielectric constant (ɛ_r) of this composition show a high value. In this paper, improvement of quality factor (Q·f) by substituting small Sr ions for Ba ions in (Ba_1−αSr_α)_6−3xSm_8+2xTi₁₈O₅₄ solid solutions, where x = 0, is reported. In addition, the relationship between crystal structure and microwave dielectric properties is discussed from the viewpoint of structural formula and occupational state of large cations such as Ba, Sr and Sm in A1-sites.     

基于案例的解释研究

解释是专家系统中一个重要环节,优秀的解释技术可以帮助用户增强使用系统的信心,帮助用户进一步理解系统的推理过程和结果.介绍基于案例解释的相关概念,然后从不同角度对近年来国内外研究进展做出综述与评价,并对基于案例的解释技术做出总结与展望.     

符号模式矩阵的幂等性质

通过对符号模式矩阵的研究,给出了具有frobenius型的符号模式矩阵中上三角块的形式,及一种构造幂等的方法,研究符号模式矩阵的符号幂等与允许幂等的关系.     

干酪乳杆菌的筛选及其在活性乳酸菌饮料中的应用

目的:为了筛选应用于活性乳酸菌饮料生产的优质益生菌。方法:以云南省各地区发酵样品中分离出的120株干酪乳杆菌为研究对象,筛选具有人工胃液、人工肠液、胆盐耐受性及对肠道致病菌有抑制作用的菌株,同时将筛选出的菌株用于褐色活性乳酸菌饮料的生产发酵实验。结果:筛选出四株干酪乳杆菌L.casei1、L.casei2、L.casei3、L.casei5,有较强的耐酸、耐胆盐及耐受人工消化液的能力;能抑制肠道致病菌:大肠杆菌、福氏志贺氏菌、肠炎沙门氏菌以及革兰氏阳性的金黄色葡萄球菌,所以具有调节人体肠道菌群平衡的益生潜力。在进行200 L发酵罐的生产摸拟实验中干酪乳杆菌L.casei1、L.casei2、L.casei3、L.casei5四株菌的褐色活性乳酸菌饮料成品在口感、稳定性及均能满足生产应用要求,具有很好的研究及应用价值。     

高阶贝塞尔-高斯光束通过圆孔硬边光阑的传输特性

文章通过把圆孔光阑函数展开为有限复高斯函数和的方法,用惠更斯-菲涅尔衍射积分,推导出了高阶贝塞尔高斯光束通过具有圆孔光阑的近轴ABCD光学系统的传输近似解析公式,并对高阶贝塞尔-高斯光束通过圆孔硬边光阑的传输特性进行了研究.分析结果表明,衍射特性与截断参数、贝塞尔函数的阶数以及光束的菲涅尔数等因素有关.     

大气边界层观测系统的故障分析与维护研究

介绍了大理国家气候观象台建设的大气边界层（PBL）观测系统,并对该系统自运行以来出现的故障进行分析和总结。试图提出一套适用于PBL观测系统特点的局部故障的分析方法,该方法可以有效提高判断仪器出现故障和数据出现异常的效率,保障数据采集的完整性、可靠性和准确性,可供维护PBL观测系统的工程技术人员参考和借鉴。     

高校图书馆网站的安全策略

高校图书馆网站是校园网的信息中心,文章通过分析图书馆网站面临的网络风险,提出了高校图书馆网站保护的安全策略。     

Data-driven optimization of hardness and toughness of high-entropy nitride coatings

High coating hardness and toughness are mutually contradicting properties and are challenging to be achieved simultaneously. Combining the vast component space of high entropy systems and the powerful high-dimensional data processing tools is expected to be the best solution to this problem. In this paper, high-entropy nitride coatings data for quinary and hexagonal systems were collected and machine learning prediction models were trained. Using a new material system combined with multi-objective optimization, high-entropy nitride coatings with the optimal hardness and elastic modulus combination were successfully obtained and verified by experiments. In addition, the partial dependence heatmaps were used to visualize how elemental content affects mechanical properties prediction in this system. This approach helped to better interpret the optimization results and discover the unknown mapping relationships between elemental content and the mechanical properties of high-entropy nitrides in machine learning models.     

Analysis of zirconia mechanical properties after application of a protocol to simulate clinical aging

In order to test the effects of hydrothermal and clinically related aging on zirconia, monolithic disc-shaped samples were milled, sintered and polished from two high translucency zirconia , 3 mol % (HT) and 5 mol % (XT). Samples were divided into three groups: non-aged: control (CT); hydrothermal aging (HA - autoclave aging for 12.5 h at 134 °C, 2 bar); in vitro clinically-related aging (CRA - chewing simulation for 1.2 million cycles followed by 50,000 thermocycles and acidic exposure in HCl, pH 1.2, for 15 h). Mechanical properties (flexural strength, fatigue, hardness and elastic modulus) were analyzed and compared using the analysis of variance (at a level of 5% significance). In vitro clinically-related aging significantly decreased fatigue strength of XT zirconia with no effects on HT zirconia. Surface hardness and elastic modulus were not affected (p = 0.591 and 0.392 respectively). Hydrothermal aging increased fatigue strength for both materials and decreased the surface hardness and modulus of HT zirconia (p ≤ 0.001). Hydrothermal aging and in vitro clinically-related aging have different effects on the mechanical properties of zirconia , when used to simulate five years of clinical service.