Cr与金刚石界面碳化物形成机理研究

选用含Cr活性钎料,适当控制钎焊工艺,实现了金刚石与基体的高强度连接。采用扫描电子显微镜（SEM）和能谱仪（EDS）及X射线衍射结构（XRD）分析了真空加热条件下,含铬活性钎料与金刚石之间的界面反应以及界面反应产物,探讨了钎料与金刚石界面处碳化物的形成机理。分析结果表明,活性钎料中的Cr在金刚石表面富集并与金刚石中的C生成枝状的碳化物,既实现了化学冶金结合,生成的碳化物呈枝状,也进一步加强了对金刚石的把持作用。     

Theoretical study on the nature of the hydrogen bonds in an α-helical polymer and its model systems

The semi-empirical CNDO/2 SCF (self-consistent field) MO (molecular orbital) method using the tight-binding approximation for polymers was applied to polyglycine. The CNDO/2 calculations were also performed on model systems of this polymer. From the calculated results, the characteristics of the hydrogen bond in the α-helix were derived by comparison with those in the model systems. It was found that the hydrogen bond in the α-helix is very stable against proton transfer whereas the hydrogen bond in the model system is not so stable; this characteristic difference between the two systems is due to the coupling of two π-electron systems through hydrogen bonding in the α-helix.     

高档精纺面料与粘合衬的粘合强力预测分析

文章应用PLS回归分析方法,对高档精纺毛面料和与其配伍的粘合衬的特征参数与粘合强力进行分析,得出了粘合强力与织物特征参数的PLS回归方程,通过对此方程的统计检验和预测值与检测值的比较,证明了用PLS方法来预测高档精纺毛面料的粘合强力是可行的.     

高温变性豆粕酶改性过程中蛋白质结构的变化

研究了高温变性豆粕(HDDSF)酶改性过程中蛋白质的结构变化,分析了高温变性豆粕蛋白质溶解性提高与结构的关系。在不同水解度(DH)下,检测酶改性处理前后的可溶性蛋白质的的表面巯基(SSH)、自由巯基(FSH)、总巯基(TSH)、二硫键(-S-S-)和表面疏水性(H0),通过SDS-PAGE图谱分析蛋白亚基变化。随着DH的提高,高温变性豆粕蛋白质溶解性增加,自由巯基和表面疏水性下降,总巯基和二硫键先上升后下降。经酶改性后蛋白质溶解性明显提高,酶解促使高温变性豆粕的不溶性蛋白质生成了以二硫键为主要化学键连接的可溶性聚合物,在酶继续作用下,生成的聚合物被最终酶解。     

水溶性PVA纤维的溶解过程及其影响因素分析

采用光学显微镜(OM)和X射线衍射(XRD),分析了完全醇解型聚乙烯醇(PVA)纤维的溶胀溶解过程.探讨了溶解温度、时间、碱剂(NaOH)和氧化剂(H2O2)对PVA纤维溶解性能的影响.结果表明:水分子渗入到纤维内部减弱无定形区的氢键作用引起纤维溶胀,纤维结晶区吸收能量破坏晶格,使水分子渗入晶区内部发生溶胀溶解.影响水溶性PVA纤维溶解性能的主要因素是溶解温度和溶解时间;Na+产生的凝聚作用抑制了PVA纤维的进一步溶解.     

The effects of salt concentration on conformational changes in cod (Gadus morhua) proteins during brine salting

The effects of different salt concentrations (6%, 15%, 18% and 24% NaCl (w/w)) on the conformational changes of cod muscle proteins during brine salting were examined in this study. Proteins were extracted from the brine salted samples with solutions of 1 M (5.9%) and 4 M (23.4%) NaCl and the quantity of salt soluble proteins (SSP), disulfide bond (S–S), total sulfhydryl (SH) and available SH content in the soluble fraction were determined. Increased salt concentration in cod muscle promoted protein denaturation and aggregation. The SSP and total SH content decreased, whereas the S–S bond and available SH content increased with increased salt concentration in cod muscle. Disulfide bond formation correlated (r = −0.6) with a decrease in total SH groups. Higher SSP and available SH groups of the samples at lower brine concentrations was explained by smaller concentration gradients and salt diffusion rates, resulting in stronger salting-in at early stages of the brining process. There was a significant difference in conformational changes in proteins extracted with a salt solution of 1 and 4 M, mainly due to a different degree of protein aggregation.     

磨料表面镀覆对陶瓷结合剂超硬磨具强度的影响

在陶瓷结合剂超硬磨具的烧结过程中,超硬磨料易受到陶瓷结合剂中某些成分的腐蚀或受到热损伤,在超硬磨料表面涂覆一层保护层,既可减轻或避免腐蚀和热损伤,还可改善磨料与结合剂之间的结合状况。文章主要对各种镀层的金刚石、c BN磨料与陶瓷结合剂按一定的比例热压烧结进行了分析说明,并测定了其抗折强度,研究了各镀层对磨具抗折强度的影响。     

纳米陶瓷结合剂超硬磨具的制造工艺

纳米陶瓷结合剂是一种新型的超硬磨具结合剂,采用它能显著降低磨具烧结温度,大幅度提高制品的强度、韧性和耐磨性,且气孔可控,为陶瓷结合剂的应用开拓了一个崭新的领域。文章阐述了纳米陶瓷的性能及应用。结果表明：纳米陶瓷结合剂抗折强度高于100MPa,经过烧结,纳米陶瓷结合剂与金刚石和cBN超硬磨料润湿性良好、结合力大,在烧结过程中与超硬磨料不发生反应、不腐蚀损伤超硬磨料。成功用于磨削PCD复合片的金刚石陶瓷砂轮。     

TCEP在羊毛角蛋白上的应用

介绍了羊毛角蛋白的溶解历史和三羧乙基膦(TCEP)在羊毛角蛋白上的应用。考虑到各种还原剂的优缺点,阐述了TCEP的优点和还原机理。三羧乙基膦是一种极为合适的部分还原试剂,对还原二硫键选择性极强。TCEP可以在很宽的pH值下将二硫键还原成巯基。TCEP广泛应用在多肽、蛋白质和细胞系统的二硫键还原及其螯合剂、配位剂。由于羊毛中含有大量的角蛋白,国内外学者将TCEP用于羊毛角蛋白的组分分析、改性和溶解。     

珍珠贝肉蛋白酶解过程浑浊形成机理研究

以浑浊度为指标,研究不同酶解时间珍珠贝肉蛋白酶解液浑浊度与粒度分布之间的联系,结果表明,二者呈正相关关系(R2=0.91);而凝胶渗透色谱表明酶解3h大部分蛋白质被降解成小分子肽,粒度分布结果显示酶解体系中粒度从383.9nm快速增加到801.4nm,氨基酸分析结果表明此过程中肽基疏水性氨基酸含量从0h的22.29%上升到3h的28.79%,而表面疏水性从559.69下降至3h的138.96,二硫键数目维持在470μmol/g,这证明了浑浊物是在酶解初期由肽凝集形成的,疏水相互作用在浑浊物形成过程中起重要作用。