担载铜镍催化剂氢溢流现象的TPR研究

本文采用TPR(Temperature Programmed Reduction)作为主要表征手段,对担载铜、镍催化剂循环还原-氧化(RedoX过程)处理前后的样品进行了表征.其次也进行了TPR测试后所得金属铜(镍)催化剂催化还原其前体氧化物(auto-catalysed reduction)的研究.发现这两种研究方式所得种种有趣结果都可归属于氢溢流现象.RedoX处理后,其TPR谱上金属氧化物的还原峰向低温区位移,并伴有总耗氢量的增加.其中峰位移可归属于Redox过程未被氧化完全的还原态金属(特别是铜)离解氢分子,形成的氢原子溢向邻近的金属氧化物(如CuO),使其在较低温度下还原;而耗氢量的增加则可归属氢原子向载体(SiO_2或Al_2O_3)的溢流,载体被活化使总耗氢量增加.上述现象可认为是同一颗粒间的氢溢流.在自催化还原过程中出现的氢溢流现象(低温区出现新还原峰和总耗氢量增加)可认为是催化剂不同颗粒间的氢溢流.总之TPR可以作为研究同一颗粒和不同颗粒间发生氢溢流行之有效的方法.     

具有氢键结构的有机材料及聚合物材料的压力诱导位移突变

利用纳米压痕技术研究了具有氢键结构的聚乙烯醇(PVA)和聚甲基丙烯酸甲酯(PMMA)的表面力学行为。与PMMA薄膜相比,在PVA薄膜的载荷-位移曲线上观察到了明显的位移突变现象。从结构差异分析可知,氢键诱导PVA薄膜产生了位移突变。为了证明结构中氢键与纳米压痕所获得的位移突变的相关性,制备了对苯二酚单晶并利用纳米压痕技术测试对苯二酚单晶的表面力学行为。结果表明,对苯二酚单晶具有氢键笼状结构,对苯二酚单晶的载荷-位移曲线载荷阶段以及保载小于临界载荷的位移-时间曲线均观察到了明显的位移突变和蠕变突变现象,并且载荷阶段的位移突变量随临界载荷的增加呈线性增加,同时位移突变还与加载速率相关。     

CPCWS中水质子的核磁共振自旋晶格弛豫时间和化学位移

运用核磁共振手段，揭示了浆体中水的形态及其动态行为，并研究浆体性质与之的关联.实验测得神府煤-石油焦-水浆（CPCWS）中水质子的化学位移与煤焦中煤的百分含量的线性关系.并从NMR测得束缚水的化学位移δb ，导出计算浆体中束缚水百分含量的公式.从CPCWS中水质子的化学位移与浆体表观粘度的相关曲线可确定最佳配比的浆体.测得全焦浆中水质子自旋-晶格驰豫时间T1比全煤浆大42倍，讨论了CPCWS的T1随煤含量的变化趋势.实验表明,T1可作为CPCWS中碳质点的疏水或亲水性以及水分子形态和动态行为的定量表征.     

^1HNMR宽峰效应及其在生物碱结构测定中的应用

在生物碱核磁波谱测试中, 当滴加微量酸时, 发现分子内与氮孤电子对空间相近的质子峰形变宽, 变钝。若酸量连续增加, 则这些信号伴有顺磁位移. 当酸量增加至生物碱摩尔浓度的六分子之一时, 该现象最明显。本文对宽峰效应现象作进一步探讨。选择几种生物碱为研究对象, 证明这一现象有一定普遍意义, 可在测定生物碱的立体构型中应用, 并探讨了诱导这一效应的原因。     

钼(钨)-钼-硫簇合物的~(95)Mo NMR研究

对含有[MS4]2-（M＝Mo，W）单元的一系列钼（钨）-钼-硫簇合物进行了95MoNMR研究，定性分析了95Mo化学位移随金属原子配位数、配位金属种类和配位金属配体改变而变化的规律。结果表明，随着[MoS4]2-配位金属原子数的增加，[MoS4]2-上Mo的化学位移逐渐向高场移动，这可归因于低氧化态MO0上的电子通过硫桥离域到高氧化态的Mo上。为了解析Mo0上化学位移的实验结果，采用MM＋力场对[（OC）4MOS2MoS2]2-和[｛（OC）4Mo｝MoS4]2-的晶体结构进行几何优化，使之更接近于溶液中的结构，然后利用Fenske－Hall方法计算Mo原子上的净电荷分布，计算结果较好地好择了Mo和Mo0化学位移的变化趋势。     

非对异构体^13CNMR化学位移不等性研究

合成了８对非对映异构体酰胺，测定了它们的＾１３Ｃ ＮＭＲ化学位移值和相应的非对映异构体基团的化学位移差，根据实验数据提出一种分子优势构象与＾１３ＣＮＭＲ化学位移不等性的相关模型。     

手性试剂TMPEA用于手性酮对映体纯度测定的研究

β-三氟甲基-β甲氧基β-苯基乙胺（TMPEA）是含氨基功能团的手性试剂[1]．由于胺可将按酸转变成酸胺，该试剂已成功地用于手性有机酸对映体的纯度测定[2]．考虑到胺同样可将醛酮转变成亚胺，本文进一步探讨了TMPEA用于手性醒酮对映体纯度测定的可行性．用R－（－）－TMPEA及dl－TMPAE分别与下列4种手性酮反应，制备相应的非对映异构亚胶：比较光活亚胺及相应的非对映异构体混合物亚腔的NMR谱，可确定各组非对映异构亚胺‘HNMR位移差（以OCH为探针基团）和’‘FNMR的位移差（以CF为探针基团）（表1）．TablelCheffiicalshif…     

Pt－Sn脱氢催化剂浸渍状态的Sn－119和Pt－195的多核NMR研究

测定了Ｐｔ－Ｓｎ型催化剂浸渍状态下的Ｓｎ－１１９、Ｐｔ－１９５的多核核磁共振。当ＳｎＣｌ２／ＤＣｌ溶液体系中加入Ｈ２ＰｔＣｌ６以后，出现了Ｓｎ（Ⅳ）和另外一种Ｓｎ（Ⅱ）的构型，Ｓｎ－１１９峰向高场位移，说明部分Ｓｎ（Ⅱ）被氧化成Ｓｎ（Ⅳ），Ｈ２ＰｔＣｌ６的量对这种氧化性影响较小。而Ｈ２ＰｔＣｌ６／Ｄ２Ｏ溶液体系中加入ＳｎＣｌ２以后部分Ｐｔ（Ⅳ）被还原成Ｐｔ（Ⅱ），随着ＳｎＣｌ２量的增加，Ｐｔ（Ⅱ）－１９５峰的强度逐渐增加而Ｐｔ（Ⅳ）－１９５峰逐渐减小。Ｐｔ（Ⅳ）－１９５较Ｐｔ（Ⅱ）－１９５峰向高场位移。在溶液状态下未发现Ｐｔ－Ｓｎ间的偶合分裂     

高分辨NMR研究苯乙烯在CTAB微乳液体系中的增溶行为

绘制了CTAB／正丁醇／水／苯乙烯构成的微乳液体系的相图，研究了增溶苯乙烯的含量对相态的影响．通过^1H NMR的测定，得出苯乙烯分子主要分布于微乳液滴的栅栏层中，而在微乳液滴内核的增溶量较少．同时，空间位阻效应使得苯乙烯分子几乎无法增溶在CTAB分子的N-CH3基团附近．通过^13CNMR谱的研究发现，苯乙烯分子在栅栏层中的增溶是不均匀的，在CYAB分子的β碳原子附近增溶量最多，增溶物苯乙烯的增溶量沿着CTAB分子的烃链自外向内逐渐减少．正丁醇分子的^13C化学位移的变化趋势呈“V”字形，正是因为苯乙烯的加入使得正丁醇分子在微乳液的分散相之间的分配发生了改变．     

中介尺度Au纳米团簇熔化的分子动力学模拟

采用分子动力学模拟技术，研究了原子个数为16～8628的 Au纳米团簇的熔化过程.采用 Johnson的EAM (embedded atom method) 模型,模拟结果表明，金属纳米团簇存在一中介尺度区域.对Au纳米团簇而言，当原子个数N >456时，团簇的热力学性质与团簇尺寸呈线性关系，熔化首先从表面开始，逐步向中心区域推进，且满足Tmb－Tmc(N)＝aN(－1/3)的关系.另外，计算了中介区域的团簇的尺寸、熔化温度、表面能、熵、焓等热力学量以及均方根位移（RMSD）等动力学量，为研究纳米团簇提供定量数据.     

以TDI和IPDI为单体合成聚氨酯微胶囊及其摩擦学性能

分别以甲苯-2,4-二异氰酸酯(TDI)和异佛尔酮二异氰酸酯(IPDI)为单体,通过原位聚合法制备了离子液体@聚脲(PU)微胶囊,并与环氧树脂共混制得环氧树脂复合材料.利用扫描电子显微镜分析了微胶囊及复合材料的表面形貌,通过电子万能试验机和摩擦磨损试验机探究了微胶囊改性复合材料在不同情况下的力学性能和摩擦学性能,用傅里叶变换红外光谱对微胶囊进行表征.分析结果表明,以IPDI为单体合成的微胶囊摩擦学性能更加优异,并且随着微胶囊用量的增加,复合材料的摩擦学性能有明显提高,当微胶囊添加质量分数为20%时,含有微胶囊的复合材料具有较低的滑动摩擦系数并且摩擦面较光滑,这是由于在实验过程中,随着微胶囊壁材的破损,芯材离子液体被释放,形成了一层致密的润滑膜.     

Fractographic relation between progressive failure and strain measurement techniques for recently developed configuration of carbon fiber/epoxy laminate

In this work, fracture mechanisms of a newly developed carbon fiber/epoxy laminate [+75/0/-75]_s were assessed by scanning electron microscopy (SEM). The composite strain-stress curves were plotted with the displacement information simultaneously acquired from both a tensile testing machine crosshead and an extensometer. The strain-stress curve plotted with the displacement data from the machine test showed an average slope change from E_1m = 22.783 GPa to E_2m = 13.170 GPa on about 65% of the total strain before global failure, while strain-stress curves plotted with displacement data from the extensometer showed one single slope. While results reported in literature related to composite failure mechanisms, where some authors reported a slope change in strain-stress curves associated to progressive failure, experimental evidence in this work for strain-stress curves showed one single slope, indicating that such slope change is related to the strain measuring technique, and not to a progressive failure. The fracture surface was studied, and four main features were observed, which were related to failure mechanisms during the uniaxial test. The identified failure mechanisms occurred on a stage above 93% of the total strain before global failure.     

Suppression of ringing oscillations from high speed rubber compression curves through a detailed modal characterization of servo-hydraulic machines

System ringing is one of the most important factors affecting the quality of data obtained in high speed dynamic material tests using servo-hydraulic machines. This phenomenon is characterized by vibrations originated by the excitation of predominant modes of the machine during tests, producing distinctive waves in material curves that severely distort the required results. In the specialized literature, the quantitative study of these vibrations has mainly been carried out considering the testing machine as a single degree of freedom system, which has led to a general understanding of the variables involved in the process. However, discrepancies between analytical predictions and experimental observations have been detected using the single degree of freedom approach, so the need for further detailed study of machine dynamic characteristics has been reported. The work presented in this paper addresses this requirement by means of a detailed characterization of the dynamic behavior of a MTS 819.10 high rate testing system. Natural frequencies, mode shapes and damping factors have been obtained from an experimental modal analysis performed on the machine and a mathematical model of the process has been developed from these modal parameters. This model has been used to detect the modes that have the greatest influence in system ringing when testing rubber at high strain rates, and to predict quantitatively the amplitudes of vibrations produced in the process. Material curves have been corrected by subtracting the predicted undulations from the original measurements, obtaining smooth curves that adequately reflect the real material behavior at high strain rates and, thus, demonstrating the effectiveness of the proposed procedure. Although the research conducted in this work has been focused on rubber, the procedure can be extended equally to characterize other materials, thus constituting a valuable tool to correct experimental measurements contaminated by ringing.     

J0.2-values by impact testing

A drop weight testing machine is described to measure the J_0.2-values of polymers in impact within the frame work of fracture mechanics. By changing the weight of a piston falling from the same drop height on the specimen, the impact velocity is constant but the impact energy is varied. This principle of impact testing is applied to the three point bending test in non-linear fracture mechanics. The apparatus is additionally instrumented with a load cell and a displacement transducer to follow the energy transfer during impact deformation in more detail. It is shown that polyethylene with shear yielding develops a strong selfstabilizing effect against crack propagation, which is less pronounced in ABS which deforms by crazing.     

细菌纤维素膜的制备与性能

以细菌纤维素为原料,氯化锂(LiCl)/二甲基乙酰胺(DMAc)为溶剂,通过相转化法制备了细菌纤维素膜.用单纤维强力仪对膜的拉伸强度和伸长率进行测试,分析了细菌纤维素浓度、凝固浴温度、凝固浴浓度、凝固时间及塑化条件对膜力学性能的影响.结果表明:在一定范围内,随着制膜液中细菌纤维素浓度的增加、凝固浴温度的降低和凝固浴浓度的增大,膜的拉伸强度和伸长率均提高;随着甘油浓度的增大和塑化时间的延长,膜的拉伸强度逐渐减小,伸长率逐渐增大.     

Measurement of flexural modulus of polymeric foam with improved accuracy using moiré method

The flexural modulus of polymeric foams determined from three-point bending tests is usually inaccurate due to the local deformation undergone by the material during testing. The machine used in the test gives deflection values larger than the actual deflection of the foam specimen due to the deformation of the material at the loading point. This leads to errors in the computation of the modulus value. In this work, the deflection values of a beam made of polymeric foam in a three-point bending test were determined using the moiré method. The change in the moiré pattern at the neutral axis of the foam during loading was recorded and converted into deflection values. The deflection data were used to generate the stress–strain curve from which the flexural modulus of the foam material was determined. The proposed method was verified using aluminum beams, where a high correlation between the deflection data from the machine readings and the moiré method was obtained. The flexural modulus of the foam determined using the moiré method was found to be within 3% of the value published in the material data sheet.     

塑料多轴冲击标准与试验技术探讨

分析比较了ISO 6603-2和ASTM D3763中关于塑料多轴冲击试验方法的异同,着重讨论了这些标准在测试技术上的不同要求,探讨了试验机性能对试验结果的影响,并提出了对试验机测控系统软硬件设计的技术要求。     

橡胶基多效协同自修复防水复合材料的研究

制备了环氧树脂改性高吸水纤维,随后将改性纤维与天然橡胶通过混、流延、压延、硫化等工艺制备了环境友好型三层复合自修复防水材料,通过SEM、FT-IR、TY-8000万能材料试验机、BTS-001电动不透水仪等考察了自修复防水材料的微观结构、机械性能、抗氧化性能、自修复性能及防渗透性能等。结果表明,高吸水纤维有助于提高其拉伸强度,最大拉伸强度为1.83MPa,断裂伸长率达到700%以上。防水材料完全切断,自修复24h后,其切口部分无可见痕迹,裂口完全愈合,且24h内无水滴渗漏。自修复48h后拉伸强度可达原始材料的2.36倍,断裂伸长率达到80%左右。     

机器视觉在光学加工检测中的应用

随着自动化控制领域的飞速发展,机器视觉技术日渐成熟,并且在各个领域赢得了越来越广泛的应用。机器视觉系统通过对图像信息的处理,用机器代替人眼实现了各种测量和判断。本综述简要介绍了机器视觉技术的概念和机器视觉系统的主要组成部分,阐述了机器视觉关键技术的发展现状,着重分析了机器视觉技术在光学加工检测领域,特别是在光学抛光检测过程中实现自动化的相关应用,最后展望了机器视觉在光学加工检测领域未来的发展趋势。     

塑料泊松比标准与试验技术探讨

分析比较了ISO 527:2012和ASTM D638-10中关于塑料泊松比试验方法的异同,重点讨论了两个标准在测试技术上的不同要求,探讨了试验机性能对试验结果的影响,并提出了对试验机测控系统设计的技术要求。