Acyl-chloride functionalized graphene oxide chemically grafted with hindered phenol and its application in anti-degradation of polypropylene

In this study,graphene oxide (GO) nanosheets were first functionalized by the acyl-chloride reaction and then reacted with hindered phenol (HP) to obtain HP grafted GO (GO-g-HP).The GO-g-HP prepared under the optimized condition exhibited a high efficiency against both thermal and photo oxidation of isotactic polypropylene (iPP).GO-g-HP exhibited a much better anti-aging efficiency than that of HP and GO used individually or that of their physical mixture.The outstanding anti-aging effect of GO-g-HP was attributed to the excellent synergistic effect produced between the chemically bonded GO and HP,which resulted in an improved oxygen barrier property of GO and excellent utilization of the free radical scavenging capability of GO and HP.Also,thanks to the grafting of HP on GO,the physical loss of HP,which was one of the main shortcomings for traditional small molecular antioxidants,was largely suppressed.It is expected that the GO-g-HP prepared can well meet the requirement of long-term applications of polymers in some harsh service conditions.     

混合低温送风方式的测试及分析

对低温蓄冷低温送水中央空调系统中采用回风、新风、露点风混合调节到合适的温、湿度的混合空气送风方式进行了能耗实验测试，测试结果证明混合送风的方式有较好的节能效果．     

火炬松树干液流的研究

采用ICT-2000TE树干液流测定系统，研究了密度为1020株/hm^2的11年生火炬松秋季树干液流特征及其与环境因子的关系。结果表明：火炬松树干液流表现为单峰曲线，日出后，树干液流迅速上升，峰值出现在中午前后，日落后至次日日出前液流微弱或几近无上升液流；树干液流速度白天10时至17时平均约26cm/h，最大达到54cm/h；不同径阶火炬松树干液流流量差异极显著。4株样木的胸径分别为13．5，10．2，15．7，16．6cm，秋季耗水量分别为13．28，13．27，36．33，49．80kg/d。环境因子对树干液流的影响次序由大到小依次为：气温、相对湿度、光合有效辐射、土壤温度、土壤水分；逐步回归建立的方程达到极显著水平。     

带堆焊层钢管焊接接头耐蚀性的电化学评定

采用电化学测试技术评价了低碳钢管管端内壁不锈钢焊条堆焊后再用相同焊条进行打底焊所得焊接接头（特别是焊接热影响区）的耐蚀性，选用两种高合金焊条M2、M6，并对堆焊金属进行热模拟试验，测定了模拟热影响区不同部位在3％NaCl介质中的阳极极化行为．结果表明，按新工艺焊接的接头代替普通碳钢焊接接头可有效地提高管道接头的使用寿命．两种焊条中，含Nb的M2耐蚀性比M6好，铌能够有效提高接头的耐均匀腐蚀、晶间腐蚀和点蚀能力，热影响区600～1000℃是高合金接头耐蚀性最薄弱的区域，建议采用超低碳含铌高合金焊条，以解决热影响区的腐蚀问题．     

现代仿古钧瓷的穆斯堡尔谱研究

利用穆斯堡尔谱分析技术，配合热分析，扫描电镜，能量色散Ｘ射线分析等方法，对现代仿古钧瓷的釉料和胎料进行了分析与研究，得到了现代仿古钧瓷的釉料和胎料在烧制过程中的相变规律；并初步了天兰钧瓷的呈色机理。     

两相闭式热虹吸管的集总参数模型研究

通过分析无芯网的两相闭式热虹吸管（简称为ＴＰＣＴ）的传热机理，提出了正常工况下ＴＰＣＴ的集总参数模型，并利用现有的热管内部传热的经验关系式，对ＴＰＣＴ在不同热负荷、不同冷却速率以及不同工质种类条件下的温度分布和动态响应特性进行了数值模拟计算．结果表明该模型简明可行     

考虑界面效应的纳米流体的热传导模型

借鉴图论的有关做法。结合威尔逊空间相互作用模型。构建区域中心城市区位选择的模型，从而试图定量分析封闭和开放两种条件下区域中心城市的适宜区位．从模型中可以看出，在封闭条件下区域中心城市适宜区位趋于区域的地理中心。而在开放条件下区域中心城市适宜区位趋于主导联系方向．作者选取浙江省嘉兴市对模型进行实证分析，分别考察了封闭和开放两种条件下嘉兴区域中心城市适宜区位的变化趋势．     

传热器件的边界元分析

采用边界元方法，对复杂的传热器件的导热规律进行了数值模拟，在控制方程的基础上，利用基本解，通过加权余量法建立内点和边界的积分方程，对边界进行剖分得到其离散化格式，通过器件边界面上的温度或热流可以计算出场内各点的温度分布，并绘制等温线．算例表明此方法有效，精度较高．     

形变和非简谐振动对SiC有效电荷和热膨胀系数以及弹性模量的影响

应用哈里森(Harrison)键联轨道法和固体物理方法,考虑到形变和原子作非简谐振动,得到六角形二维类石墨烯AN-B8-N化合物的热膨胀系数、弹性模量以及有效电荷的解析表示式;以SiC为例,探讨了形变和原子非简谐振动对它们的影响.结果表明:SiC的热膨胀系数和弹性模量均随温度升高而缓慢增大,但变化较缓慢;若不考虑非简谐项,则SiC的热膨胀系数和弹性模量均为零,非简谐效应是SiC的热膨胀系数和弹性模量均随温度升高而增大的原因;形变会使SiC的正负离子的有效电荷的大小均减小,减小幅度分别为14.5%和8.56%,形变对正离子有效电荷的影响大于负离子.在所述的大小、剪切、轴向拉伸、原子振动形变这几种形变中,以轴向拉伸形变对有效电荷的影响最大,以大小形变和剪切形变的影响最小.温度愈高,原子的非简谐振动效应愈显著,形变对SiC的极性和有效电荷的影响愈大.     

Damage evolution and failure mechanism of thermal barrier coatings under Vickers indentation by using acoustic emission technique

Acoustic emission(AE) technique was adopted to monitor the damage evolution of air plasma-sprayed(APS) yttria-partially-stabilized zirconia(YSZ) thermal barrier coatings(TBCs) during instrumented indentation testing, and then the failure mechanisms were investigated by cluster analysis and wavelet transform methods.The results of cluster analysis showed that there were three classes associated with distinct failure types for the 8YSZ coatings under Vickers indentation. Based on wavelet transform, these three clusters could be clearly distinguished from their dominant frequency bands, which were concentrated on levels A5(0–156.25 kHz), D5(156.25–312.5 kHz) and D4(312.5–625 kHz), respectively. Thus, the failure mechanism of 8YSZ coatings under Vickers indentation could be clarified by the distribution of different failure types in indentation depth. To sum up, as indentation load increases, the 8YSZ coatings can accommodate the indenter by elastic or little plastic deformation, microcracks propagation and then debonding at the splat boundaries. By comparing the distribution of AE signals induced by different failure types in indentation depth for samples with different thermal exposure time, it can be inferred that thermal exposure treatment can accelerate the degradation of APS 8YSZ TBCs.