Chemical bond characteristics and infrared reflectivity spectrum of a novel microwave dielectric ceramic CaIn2O4 with near-zero τf

Orthorhombic-structured CaIn₂O₄ ceramics with a space group Pca2₁ were synthesized via a solid-state reaction method. A high relative density (95.6 %) and excellent microwave dielectric properties (ε_r ～11.28, Qf = 74,200 GHz, τ_f ～ ?4.6 ppm/°C) were obtained when the ceramics were sintered at 1375 °C for 6 h. The dielectric properties were investigated on the basis of the Phillips–Van Vechten–Levine chemical bond theory. Results indicated that the dielectric properties were mainly determined by the InO bonds in the CaIn₂O₄ ceramics. These bonds contributed more (74.65 %) to the dielectric constant than the CaO bonds (25.35 %). Furthermore, the intrinsic dielectric properties of the CaIn₂O₄ ceramics were investigated via infrared reflectivity spectroscopy. The extrapolated microwave dielectric properties were ε_r ～10.12 and Qf = 112,200 GHz. Results indicated that ion polarization is the main contributor to the dielectric constant in microwave frequency ranges.     

深部开采煤柱载荷在底板岩层传递影响角的探讨

在阐明深部巷道围岩变形机理的基础上，对煤柱支承压力在底板传播规律和煤柱载荷在底板岩层传递影响角进行了分析，并结合实测资料，提出了测定煤柱影响的方法，为深部开采底板巷道合理位置选择提供了依据。     

一起典型火灾事故原因分析

通过对钻孔工艺过程、钻孔发火机理展开分析,找出了告成矿瓦斯抽放钻场火灾原因,提出了防范措施。     

茶马古道双镇记——兼论传统城镇的保护与发展

该文介绍了云南省两个茶马古和丽江束河。作者通过这两个古镇的多方位的描述、比较，特别是旧城更新思路的对比，指出①抟统城镇的现状不容乐册，及时发现问题并寻求实际解决办法刻不容缓，②传统城镇的保护不能等待机会而是要创造机会，只有发展才能促保护，③传统城镇的更新要着力挖掘并凸显地方最具特色的文化底蕴，④保护与发展同等重要，把握其中的“度”最为关键。     

“则天故里”——皇泽寺

地处中国西部川陕甘交界之处的川北边缘城市广元市,古称"利州",亦称"则天故里". 广元之所以称为"则天故里",是因为它是中国历史上唯一的女皇帝--武则天的诞生地,所以古城与女皇齐名,千秋溢彩,名扬天下.再因围绕广元一带的皇泽寺、千佛崖、葭萌关、朝天并、飞仙关、七盘关、潭毒关和三国遗址、古栈道等的诱惑力,所以这里成为古人和今人神往的旅游胜地.     

Enzymatic biosensor for nitrite detection based on direct electron transfer by CPO-ILEMB/Au@MoS2/GC

Journal of Applied Electrochemistry - A novel nitrite electrochemical biosensor is constructed by glassy carbon electrodes (GC) coated by chloroperoxidase (CPO) -Au nanoparticles-MoS2 nanoflowers...     

常用预应力锚索的结构和特点

3．2施工中要注意的问题 3．2．1锚固段钢绞线的清洗拉力型锚索的拉力是依赖钢绞线与注浆体的粘结力经由注浆体传递给孔周的岩体,因此,锚固段钢绞上的油脂必须清洗干净。钢绞线上的防锈脂已渗入7根钢丝的内部空间,不能只清洗表面,必须把钢绞线散开,7根钢丝分别洗干净后再复原。这样做很麻烦,仅适用于锚索量小的工程。对于大型边坡工程,宜采用在封闭容器内用90℃以上高温水喷射清洗,这种方法不用散开钢绞线而且洗得干净;     

Sensing Leakage of Electrolytes from Magnesium Batteries Enabled by Natural AIEgens

The potential for leakage of liquid electrolytes from magnesium (Mg) batteries represents a large hurdle to future application. Despite this, there are no efficient sensing technologies to detect the leakage of liquid electrolytes. Here, we developed a sensor using laccaic acid (L-AIEgen), a naturally occurring aggregation-induced emission luminogen (AIEgens) isolated from the beetle Laccifer lacca. L-AIEgen showed good selectivity and sensitivity for Mg²⁺, a universal component of electrolytes in Mg batteries. Using L-AIEgen, we then produced a smart film (L-AIE-F) that was able to sense leakage of electrolytes from Mg batteries. L-AIE-F showed a strong “turn-on” AIE-active fluorescence at the leakage point of electrolyte from model Mg batteries. To the best of our knowledge, this is the first time that AIE technology has been used to sense the leakage of electrolytes.     

红土镍矿为原料制备白炭黑的最佳工艺研究

以红土镍矿为原料,采用碱熔融-碳酸化分解方法制备出白炭黑产品。通过正交试验L₉(3⁴),找到碱熔融反应的最佳工艺条件：碱矿质量比150/50,反应温度823 K,反应时间3.5 h,原料粒度1.704 μm。该条件下放大试验二氧化硅转化率为79.10%。浸出液经碳酸化分解制得白炭黑产品符合国家HG/T3065-1999标准。碳酸化分解后所得溶液经苛化工艺实现碱和二氧化碳的循环利用。     

ZA27铸造合金的凝固特性

研究了ZA27铸造合金中的常见微量元素以及铸件厚度、浇注温度、变质处理对ZA27合金凝固特性的影响。实验结果表明,铸件厚度是影响ZA27合金凝固特性的最主要因素,适量的Ti可以改善ZA27合金的凝固特性,浇注温度及变质处理对ZA27合金的凝固特性也有不同程度的影响。根据实验结果,推荐了较佳工艺参数。