聚氨酯黏结剂加入催化剂对釉-瓷黏结性能的影响

背景:虽然聚氨酯黏结剂具有的较强的黏结力,但其黏结条件不符合应用于口腔黏结剂的基本条件。目的:观察催化剂对聚氨酯黏结剂黏结性能的影响。方法:选择20颗无龋坏青年人前磨牙或前牙制备牙釉质黏结面,铸造40个直径3mm、高3mm的圆柱状瓷块,分组黏固,每组5颗离体牙,10个瓷块:辛酸亚锡黏结剂组(以聚氨酯黏结剂与辛酸亚锡联合黏固)、五甲基二乙烯三胺黏结剂组(以聚氨酯黏结剂与五甲基二乙烯三胺联合黏固)、单纯聚氨酯黏结剂组、帕娜碧亚黏结剂组。结果与结论:辛酸亚锡黏结剂组黏结强度最大,五甲基二乙烯三胺黏结剂组和单纯聚氨酯黏结剂组次之,帕娜碧亚黏结剂组最小。辛酸亚锡黏结剂组、五甲基二乙烯三胺黏结剂组、单纯聚氨酯黏结剂组黏结强度均高于帕娜碧亚黏结剂组(P<0.05),且辛酸亚锡与五甲基二乙烯三胺的加入缩短了黏结剂凝固时间。说明催化剂可有效缩短聚氨酯黏结剂的凝固时间,提高聚氨酯黏结剂的黏结强度。

Blast response of full-size concrete walls with chemically reactive enamel （CRE）-coated steel reinforcement

In this study, two full-size concrete wails were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel （CRE） coating in improving their mechanical behavior under blast loading： one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene （TNT） charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface sWain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests.

Study on the diversification of origins and primary development of Chinese porcelain glazes

With the support of the Origin Exploring of Chinese Civilization Projects (II) and National Natural Science Foundation of China,the close relationship among "pottery coat","kiln sweat" and Chinese proto-porcelain glaze were studied,the characteristics and the key foundation of the origin of porcelain glaze were also discussed based on the relevant research results by Shanghai Institute of Ceramics,Chinese Academy of Sciences and Jingdezhen Ceramics Institute.