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101.
Study on the relationship between the particle size distribution and the effectiveness of the K‐powder fire extinguishing agent 下载免费PDF全文
The relationship between the particle size distribution and the extinguishing effectiveness of the new K‐powder fire extinguishing agent has been studied experimentally, to explore the reason of the great extinguishing efficiency exhibited by the new K‐powder fire extinguishing agent on Class B fire (liquid fuel fire). The results of the experiment showed that the extinguishing effectiveness increased along with the decrease of the particle size distribution. In addition, a sharp discontinuity appeared around the limiting size, about 40 μm. The powder with the particle size below 40 μm exhibited highly effective extinguishing with the minimum effective extinguishing concentration Cxr = 23 g·m?3, while the powder with the particle size above 40 μm exhibited little fire extinguishing efficiency. Compared with other fire extinguishing agents produced by different substances, the new K‐powder fire extinguishing has the bigger limiting size. That means, in the same particle size distribution, the new K‐powder fire extinguishing agent contains more highly effective powder than others contain, and is more effective. 相似文献
102.
针对大型旋转机械通过临界转速时振动过大及运行中故障频发等问题,搭建转子试验台,模拟启停机过程和碰摩、不对中故障。不改变原有支撑形式,安装自主设计的磁流变阻尼器,在不停机的情况下,试验研究阻尼器抑制转子通过临界转速时振动过大及各类故障振动。试验结果表明,阻尼器可以有效抑制转子系统临界转速附近的振动,降幅在60%以上;转子发生碰摩或不对中故障时,阻尼器可以降低其高倍频振动。 相似文献
103.
Dr. Yahu A. Liu Dr. Qihui Jin Qiang Ding Dr. Xueshi Hao Tingting Mo Shanshan Yan Dr. Yefen Zou Dr. Zhihong Huang Xiaoyue Zhang Wenqi Gao Dr. Tom Y.-H. Wu Chun Li Dr. Badry Bursalaya Dr. Michael Di Donato Dr. You-Qing Zhang Lisa Deaton Dr. Weijun Shen Dr. Brandon Taylor Anwesh Kamireddy Dr. George Harb Dr. Jing Li Dr. Yong Jia Dr. Andrew M. Schumacher Dr. Bryan Laffitte Dr. Richard Glynne Dr. Shifeng Pan Dr. Peter McNamara Dr. Valentina Molteni Dr. Jon Loren 《ChemMedChem》2020,15(16):1562-1570
Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation. 相似文献
104.
“Smart firefighting” construction as a part of the “smart city” has been a concern of the public security and fire agencies at all levels. In this study, the status, problems, and reflections of “smart firefighting” construction in China are discussed. A recent survey indicates that China has launched its smart firefighting construction and initially created a new perspective on its regional smart firefighting work based on three main aspects: intelligent disaster perception by Internet of Things (IoT) construction, intelligent disaster prevention by big data construction, and intelligent disaster disposal by emergency rescue platform construction. However, the current smart firefighting construction in China still has some prominent problems such as the data interconnectivity and normalized management of various platforms, the extensibility of smart firefighting platforms, and the intelligent level of smart firefighting researches, which need to be solved urgently. Therefore, we argue that smart firefighting construction in China should establish data interconnectivity, industrial normalized management, 2D/3D geographic information interaction and extension, high-integration fire protection theory, and many other aspects in the near future and truly realize firefighting visualization and efficient data applications for 4D time space. This study could provide valuable reference for smart firefighting and smart city construction. 相似文献
105.
Jiaao Yan Gao Zhiming Tan Qingchao Yang Xian Hu Wenbin 《Protection of Metals and Physical Chemistry of Surfaces》2020,56(5):965-972
Protection of Metals and Physical Chemistry of Surfaces - The Al2O3 powder was added as a filler to polyurea and the effect of doping amount on Shore hardness and wetting property were... 相似文献
106.
Synergistic flame retardant effects of activated carbon and molybdenum oxide in poly(vinyl chloride) 下载免费PDF全文
Mengjiao Zhang Weihong Wu Shaorui He Xue Wang Yunhong Jiao Hongqiang Qu Jianzhong Xu 《Polymer International》2018,67(4):445-452
The synergistic effects of activated carbon (AC) and molybdenum oxide (MoO3) in improving the flame retardancy of poly(vinyl chloride) (PVC) were investigated. The effects of AC, MoO3 and their mixture with a mass ratio of 1:1 on the flame retardancy and smoke suppression properties of PVC were studied using the limiting oxygen index and cone calorimeter tests. It was found that the flame retardancy of the relatively cheaper AC was slightly weaker than that of MoO3. In addition, the incorporation of AC and MoO3 greatly reduced the total heat release and improved smoke suppressant property of PVC composites. When the total content of AC and MoO3 was 10 phr, PVC/AC/MoO3 had the lowest peak heat release rate and peak smoke production rate values of 173.80 kW m?2 and 0.1472 m2 s?1, which represented reductions of 47.3 and 59.9%, respectively, compared with those of PVC. Furthermore, thermogravimetric analysis and gel content tests were used to analyze the flame retardant mechanism of AC and MoO3, with results showing that AC could promote early crosslinking in PVC. Char residue left after heating at 500 °C was analyzed using scanning electron microscopy and Raman spectroscopy, and the results showed that MoO3 produced the most compact char, with the smallest and most organized carbonaceous microstructures. © 2017 Society of Chemical Industry 相似文献
107.
Yan Xiong Xianwu Du Mingyu Xiang Hao Wang Weimin Wang Zhengyi Fu 《Journal of the European Ceramic Society》2018,38(12):4167-4172
The densification behaviors of pure B4C and B4C-ZrO2 mixtures were compared during hot pressing. The results showed that in-situ formed ZrB2 effectively enhanced the densification process of B4C-ZrO2 mixtures, more significantly during the intermediate stage. Within the relative density ranging from 0.75 to 0.90, the B4C-15?wt%ZrO2 mixture (B15Z) achieved the maximum densification rate as twice much as that of pure B4C. The stress exponent n>3 indicated plastic deformation was the dominant densification mechanism of B15Z. The viscosities of plastic flow were evaluated using Murray-Rodger-William equation and the viscosity of B15Z was only a quarter of that in pure B4C. The sintering activation energy was calculated to be 305.9?kJ/mol for pure B4C and 197?kJ/mol for B15Z, respectively. It was proposed that the lower viscosity of plastic flow and activation energy accelerated the sliding and propagating motions of plastic flow, by which underlain the enhanced densification behaviors of B4C-ZrO2 mixtures. 相似文献
108.
新疆卤水硝酸盐矿主要含有Na+、K+、Mg2+、Cl-、NO3-、SO42-六种离子,属于高元复杂体系,其合理利用和开发需要不同温度下的相平衡研究作为理论支撑。采用等温溶解平衡法,对Na+, K+, Mg2+//Cl-, NO3-, SO42--H2O体系在-15℃、NaCl·2H2O饱和条件下的相平衡进行了研究,并构建了相图。相图中有六个零变量点和八个两盐结晶区,只存在一种复盐KCl·MgCl2·6H2O。八个两盐结晶区,分别对应于NaCl·2H2O+Na2SO4·10H2O、NaCl·2H2O+NaNO3、NaCl·2H2O+KCl、NaCl·2H2O+KNO3、NaCl·2H2O+MgSO4·7H2O、NaCl·2H2O+MgCl2·8H2O、NaCl·2H2O+Mg(NO3)2·6H2O和NaCl·2H2O+KCl·MgCl2·6H2O,其中NaCl·2H2O+Na2SO4·10H2O共晶区最大,在低温时,硫酸钠的溶解度最小,降温过程中较易结晶析出。与该体系在25℃下的相图相比,复盐种类减少5种,零变量点减少19个,相关系得以极大简化。 相似文献
109.
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