Solution Crystallization Behavior of Linear and Star-shaped Poly(ethylene glycol)-b-Poly(ε-caprolactone) Block Copolymers简

Lamellar crystals of diblock, triblock and four-arm poly（ethylene glycol）-b-poly（ε-caprolactone） （PEG-b-PCL） crystalline-crystalline copolymers were successfully obtained from their solution. Morphology and structure of lamellar crystals of crystalline-crystalline copotymers were investigated using tapping-mode atomic force microscopy （AFM） and selected area electron diffraction （SAED）. All of these samples showed the truncated-lozenge multilayer basal shapes with central screw dislocation or central stack, which were all obtained simultaneously from the oil bath. The diffraction pattern of PEG block lamellar crystal is attributed to the （120） diffracting planes and the pattern of PCL block lamellar crystal is attributed to the （1 I0） diffracting planes and （200） diffracting planes according to the SAED results. Four （110） crystal growth planes and two （200） crystal growth planes are discovered for the PCL blocks, but the （120） crystal growth planes of PEG blocks are hided in the figure of AFM. The crystalline structure of the four-arm copolymers （FA） is more disorder and confused than that of the diblock （DI） copolymer and the striated fold surface structures of lamellar crystals of four-arm copolymers （FA） are smoother than these of linear analogues, owing to the confused crystallization of blocks caused by the mutual restriction of blocks and the hindrance of the dendritic cores. In addition, the aspect ratio of FA is greater than that of the others. It is hypothesized that there are two reasons for the change of aspect ratios. First, the （200） diffracting planes of PCL crystals grew slowly compared to their （110） diffracting planes because of difference in the energy barrier. Secondly, edge dislocations on the （200） diffracting planes are also responsible for the variation of the aspect ratio. Consequently, the crystalline defects are augmented by the competing blocks crystallized simultaneously and the hindrance of the dendritic cores.     

生物样品中儿茶酚胺类物质分析方法的研究进展

儿茶酚胺是人体内重要的神经递质,血浆及尿中儿茶酚胺的浓度水平可用于诊断高血压、嗜铬细胞瘤及成神经细胞瘤等病症,因而准确测定人体生物样品中儿茶酚胺类物质代谢浓度的变化,在疾病的诊断和治疗中具有重要的意义。该文综述了人体液和组织中儿茶酚胺类物质的不同分析方法,包括高效液相色谱法、毛细管电泳法、质谱法、电化学法、化学发光法、荧光光度法等。     

近独立子系系统的统计规律(四)——巨正则分布函数

根据吉布斯系综理论导出了由任意数目刚性粒子构成的力学系统的巨正则分布函数、化学势及粒子数和能量涨落公式.并介绍了刚球模型下,对二维和三维近独立子系系统巨正则分布的计算机模拟,结果与理论完全一致.     

近独立子系系统的统计规律(三)——正则分布函数及能量涨落公式

从系综理论出发,导出了由任意数目和不同质量的刚性粒子构成的二维和三维力学系统的正则分布函数及能量涨落公式,我们的计算机模拟与该理论一致.     

毛细管区带电泳分析阿片受体和抗独特型抗羟甲芬太尼抗体

应用毛细管区带电泳（ＣＺＥ）分析测定阿片受体、抗独特型抗羟甲芬太尼抗体等生物大分子样品。熔融石英毛细管柱为６０ｃｍ×１００μｍｉ．ｄ．（从进样到检测器长度为５０ｃｍ）,以硼砂－氢氧化钾为缓冲液。结果表明缓冲液的ｐＨ影响ＣＺＥ对阿片受体的分析,当ｐＨ为９．０时分析效果最理想,重现性良好,测得的两个主峰与同批样品进行ＳＤＳ－ＰＡＧＥ分析得到的两个条带相符。用ＣＺＥ分析抗独特型抗羟甲芬太尼抗体（ＩｇＧ）,表明用ＰｒＯｔｅｉｎＡ－Ｓｅｐｈａｒｏｓｅ亲和色谱分离得到部分纯化的ＩｇＧ,迁移时间不同于对照豚鼠的ＩｇＧ。     

分光光度计改装为用于高压液相的检测器

高速液相色谱仪常配有单波长紫外检测器,检测灵敏度最高可达2×10~(-5)-5×10~(-5)吸光度,但缺点是有些试样在254毫微米处没有吸收或吸收很小。紫外分光检测器则可以按照被测试样的吸收情况任意选择检测波长以提高检测灵敏度,因此为国外商品仪器所普遍采用。这种检测器,实际上就是一种简易的分光光度计,但与一般分光光度计不同的是它必须具有以下特点: 1.必须配有容积较小的流动型样品池,一     

在高压CO_2中聚乙二醇-聚己内酯嵌段共聚物的结晶行为

通过广角X射线衍射(WAXD)和小角X射线散射(SAXS)方法研究了PEO-b-PCL在CO2中的结晶形貌和片晶厚度的变化,利用高压示差扫描量热仪(HP DSC)考察了压力对熔融和等温结晶过程的影响.结果表明,PEO-b-PCL的结晶度、片晶厚度、熔融温度均随压力的升高而减小,结晶结构变得不完善.在等温结晶过程中,结晶速率随压力的升高而下降,结晶过程处于成核控制区,Avrami指数n在3.7~4.7,表明晶体的生长方式为三维生长.     

Crystallization and morphology of star-shaped polyethylenoxyde-b-polycaprolactone under high pressure carbon dioxide

Atomic force microscopy（AFM）,wide-angle X-ray diffraction（WAXD） and differential scanning calorimetry are used to analyze the crystallization morphology and melting behavior of 4-arm PEO-b-PCL under high-pressure CO₂.It is demonstrated that CO₂ has certain effect on the melting and crystallization behavior of the samples.After crystallization under CO₂ at 4 MPa,spherulites with concentric ring-banded structure are formed which are composed of crystals with periodic thickness variation,and the band distance decreases with increasing treatment pressure.Due to the plasticization effect of CO₂,depression of the melting temperature is observed with sorption of CO₂ in polymers.     

高效液相色谱-电喷雾串联四级杆质谱法检测小鼠组织中花生四烯酸及其代谢产物

采用反相高效液相色谱梯度洗脱,电喷雾串联质谱多反应检测模式,同时分离测定小鼠组织中花生四烯酸类代谢产物.组织样品经低温超声破碎细胞,采用乙酸乙酯进行两次萃取,LC-MS/MS检测.实验用3个内标,标准溶液稀释法建立了19种花生四烯酸类物质的标准曲线.方法学确证表明: 各被测物质的线性相关系数均大于0.99;定量限(LOQ)为3～250 μg/L;相对回收率在70.7%～123.0%之间;方法重复性(RSD)均小于20%.运用本法在小鼠肺、肝、脾组织中检测到了几种花生四烯酸类代谢产物,并对肺组织里的8种代谢产物进行了含量测定,结果为11-羟基二十碳四烯酸(58.3±11.6)ng/g,15-羟基二十碳四烯酸(52.6±15.5)ng/g,前列腺素E2(210±102) ng/g,前列腺素D2(20.3±13.9)ng/g,前列腺素J2(39.2±15.9)ng/g,血栓素B2(58.3±28.4)ng/g,前列腺素F2α(3.8±6.0) ng/g,花生四烯酸(1980±544)ng/g.本方法灵敏度高、重复性良好,为研究生物组织样品中花生四烯酸类物质的代谢状况提供了分析基础.     

三种不同基体中玻璃微球悬浮体系的流变行为

三种不同基体中玻璃微球悬浮体系的流变行为吴大诚，陈军武，徐建军，杜鹏，顾群，李玉景（成都科技大学纺织工学院成都６１００６５）关键词高分子流变学，Ｂｏｇｅｒ流体，悬浮体，聚异戊二烯悬浮体的流体动力学研究始于本世纪初，Ｅｉｎｓｔｅｉｎ“对极稀悬浮体粘度的...