中国式学科评估:问题与出路

今年四月份,教育部学位与研究生教育发展中心(以下简称"教育部学位中心")邀请全国学位授予单位参加全国第四轮一级学科整体水平评估。随之,各个高校展开了一场大规模、高级别的学科评估申报及材料提交总动员。第四轮学科评估自发布起也引发了学界的广泛关注和热烈讨论。高等教育是中国崛起的思想发动机,关涉民族复兴的未来,而学科评估是近年来中国高等教育学科建设成就的集中展示,其意义和影响可谓深远。为了更好推进学科评估科学进行,特别是促进高等教育健康发展,《探索与争鸣》编辑部邀请全国

刚玉基多孔陶瓷的低温制备及性能研究

多孔陶瓷因其具有高效、绿色、稳定等特点而被广泛应用于水体净化、工业产品除杂、高温烟气除尘等领域，显示出了优异的应用可靠性。传统多孔陶瓷制品需要在高温条件下烧结制备，因此制品生产能耗高，且制造成本居高不下，限制了多孔陶瓷的广泛应用。本论文以不同粒度的刚玉颗粒为骨料，以磷酸盐和树脂作为结合剂，在低温（&lt;1000℃）下制备多孔陶瓷。主要内容如下：对磷酸盐结合刚玉基多孔陶瓷的制备及耐水性进行了研究，为了克服磷酸盐结合多孔陶瓷材料易与水反应造成强度衰减问题，系统研究了成型工艺和耐水改性剂种类对磷酸盐结合刚玉基多孔陶瓷材料理化性能的影响。研究发现：硅溶胶-硼酸改性的刚玉基多孔陶瓷具有较佳的综合性能，浸水后抗弯强度保持率达94.23%；亚微米SiO2的引入得到了更加均匀分布的耐水相，强化了材料的疏水效果；硼酸热处理后裂解形成的B2O3玻璃相弥补了磷酸盐结合相变化产生的缝隙，减少了结合相颗粒生长造成的水渗透通道数量。采用塑性工艺成型时，加水量为12%时材料具有最优的综合性能。单向加压工艺会造成不规则刚玉骨料的取向偏转，这虽有利于材料强度的提高，但影响了材料孔隙的均匀性，因此成型压力不宜超过14 MPa。对环氧树脂结合刚玉基多孔陶瓷进行了研究，主要考察树脂种类和用量、刚玉颗粒尺寸和改性剂对材料性能的影响。研究发现：油性环氧树脂结合刚玉基多孔陶瓷材料比水性树脂结合材料具有更高的强度。添加5 wt%油性双酚F环氧树脂结合的刚玉基多孔陶瓷，在孔隙率为36.81%时具有较高的强度，达20.98 MPa。然而，在常温浸水48 h后，试样强度明显下降，造成强度损失的原因主要是结合相发生了断裂。加入1.2 wt%KH-560偶联剂对材料进行改性后，试样浸水强度得到很大改善，强度保持率提升至80%。;Porous ceramics are widely used in water purification, industrial product decontamination, high-temperature flue gas filtration and other fields due to their high efficiency, greenness, stability and other characteristics, showing excellent application reliability. Traditional porous ceramic products are always sintered under high temperature conditions, so the energy consumption of the products is high, and the manufacturing cost remains high, which limits their widespread application. In this paper, corundum particles with different size are used as aggregates, and phosphate and resin are used as binders to prepare porous ceramics at low temperature (&lt;1000℃). The main contents are as follows:The preparation and water resistance of corundum-based porous ceramics combined by phosphate were studied. In order to overcome the strength attenuation of phosphate-bonded porous ceramics, caused by reacting with water, the influence of molding process and kinds of water-resistant modifiers on physical and chemical properties of corundum-based porous ceramics combined by phosphate were systematically studied. The results found that corundum-based porous ceramics modified by silica sol-boric acid have better comprehensive performance, and have higher flexural strength retention rate of 94.23% after immersion in water. The introduction of submicron SiO2 results in a more uniformly dispersed water-resistant phase, which strengthens the hydrophobic effect. The B2O3 glass phase formed by boric acid pyrolysis after heat treatment makes up the gap caused by the change of phosphate binding phase and reduces the number of water permeation channels caused by the growth of the particles of the binding phase. When plastic molding is used, the material has the best comprehensive performance when the water content is 12%. The unidirectional press moulding will cause the orientation deflection of irregular corundum aggregate, which is beneficial to the improvement of the testing strength, but affects the uniformity of the pores of the material, so the molding pressure should not exceed 14 MPa.The corundum-based porous ceramics combined by epoxy resin was studied, mainly to investigate the effects of resin type, adding amount, corundum particle size and modifier on material properties. The study found that corundum-based porous ceramics combined by oily epoxy resin has higher strength than those combined by water-based resin. The corundum-based porous ceramic containing 5% weight of oily bisphenol F epoxy resin has higher strength of 20.98 MPa when the porosity is 36.81%. However, after immersion in water at room temperature for 48 h, the strength of the sample decreased significantly. The main reason for the strength loss was the fracture of the bonding phase. After adding 1.2 % weight of KH-560 coupling agent to modify the material, the immersion strength of the sample is greatly improved, and the strength retention rate is increased to 80%.</p

垂直腔面发射激光器的TO封装的耦合效率模拟分析

采用FRESNEL光学软件和MATLAB软件，详细分析了垂直腔面发射激光器的TO封装组件对耦合效率的影响．发现增加耦合透镜的折射率、减少管帽的高度和耦合透镜的尺寸可以提高耦合效率

波长编码的光时域反射测试装置及其测量方法

本发明公开了一种波长编码的光时域反射测试装置及其测量方法。装置包括光波长编码发生器、光纤分路装置、偏振控制器、光纤耦合器、光电探测器和拍频信号检测装置。光波长编码发生器产生的编码光脉冲信号从光纤分路装置的第一端口输入，分为探测光信号和参考光信号分别从光纤分路装置的第二端口和第三端口输出；探测光信号进入待测光纤链路中，遇到待测光纤链路的断点或损伤点后产生的反射光信号从第二端口返回光纤分路装置并从第四端口输出；反射光信号经过偏振控制器后与参考光信号一起通过光纤耦合器，进入光电探测器进行拍频，拍频低频信号进入拍频信号检测装置进行观测和记录。本发明解决了传统OTDR分辨率与动态范围无法同时提高的问题