硬质聚氯乙烯中空型材冷却定型模的设计

介绍了硬质聚氯乙烯塑料中空异型材冷却定型装置的设计,通过典型实例讨论其设计方法、设计要素和经验体会。     

[(PbCl_2)_(0.55)(PbO)_(0.45)]_(1-x)(KCl)_x系的混合晶界效应

本文通过混合晶界效应模型,对[(PbCl_2)_(0.55)(PbO)_(0.45)]_(1-x)(KCL)_x体系中当O.05≤x≤0.22时为x≤0.03(主相为3PbCl_2·2PbO)和x≈0.25(主相为Pb(OH)Cl型物相)两个高导电相的混合相,且电导率低下的现象进行了说明,并通过解析阻抗谱做了验证.     

高纯度PAN基碳纤维及其原丝的研制

对用几种方法制取的高纯度PAN原丝进行了分析对比,选取了以无碱金属引发体系的HNO_3溶液聚合工艺制得原液并纺制了碱金属及碱土金属总含量小于100ppm的高纯级PAN原丝。将其与其余三种一般纯度的PAN纤维以同样氧化、碳化工艺制得了碳纤维,并以密度、质量比电阻、X—光衍射、扫描电子显微镜、热分析及原子吸收光谱等方法研究了高纯碳丝及原丝的特点。     

单柱离子色谱测定碱金属与碱土金属的研究及应用

本文用Shimadzu HIC-6A高效单柱离子色谱仪和Shim-pack IC-CI低容量阳离子色谱柱,研究了不同浓度与不同pH值的淋洗剂对金属离子保留行为的影响,优选4.0 m mol/L HNO_3淋洗同时测定Li~+、Na~+、K~+、R6~+和Cs~+离子以及优选1.25m mol/L乙二胺和5.00m mol/L柠檬酸淋洗同时测定Be~(2+)、Mg~(2+)、Ca~(2+)、Sr~(2+)和Ba~(2+)离子的最佳色谱条件,并用于饮水的测定.本法标准加入回收,碱金属5种离子的回收率达101.2%～103.5%;碱土金属5种离子的回收率达99.80%～107.7%.水样分析,Na~+和K~+离子的RSD为0.86%和1.02%,Mg~(2+)和Ca~(2+)离子的RSD为0.364%和0.70%。     

河南老湾花岗岩的源区成分模拟

老湾花岗岩的岩石化学、稀土元素和同位素特征指示出老湾花岗岩源于下地壳经部分熔融作用形成。源岩中含有壳源和幔源物质,具类似于高钾钙碱性安山岩的岩石化学特点。详细的研究表明了早元古界桐柏山群不能成为老湾花岗岩的源岩。模拟的太古代岩系岩石化学成分经高程度的部分熔融作用可以形成老湾花岗岩。     

Arachidonic acid release by ionomycin and phorbol ester is similar in C127 epithelial cells expressing wild-type or mutated (ΔF508) cystic fibrosis transmembrane conductance regulator

The Ca²⁺ ionophore ionomycin induced cytosolic [Ca²⁺]_i elevation as well as strong activation of Cl⁻ efflux in mouse mammary epithelial cell lines expressing wild-type or mutated (deletion of phenylalaline 508) cystic fibrosis transmembrane conductance regulator (CFTR) or vector. Ionomycin-induced Cl⁻ efflux was abolished by the intracellular Ca²⁺ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, whereas both activators and inhibitors of phospholipase A₂ had no effect, indicating the involvement of Ca²⁺-dependent Cl^- channels. Stimulation of arachidonic acid release by ionomycin and phorbol ester was not significantly different between wild-type or mutated cell lines, whereas vector-transfected cells exhibited a significant higher release, which was shown to be due to larger amount of immunoreactive cytosolic phospholipase A₂. These results indicate that phospholipase A₂ activity of C127 cells was not influenced by the presence of wild-type or mutated CFTR. Received 27 April 1999; received after revision 11 June 1999; accepted 23 July 1999     

铂-钨非配偶型电极上钯（Ⅱ）的零电流示波电位滴定法及其应用

以氯化十六烷基吡啶(CPC)为滴定剂,用铂片电极和钨棒电极为指示电极,利用阴极射线示波器荧光屏上荧光点的突然位移来指示CPC滴定Pd(Ⅱ)的终点,具有简便准确,快速直观等特点.用该法测定陶瓷亮钯金水中的钯结果良好.     

吡啶类添加剂存在下对苯二甲酰氯与对苯二胺的低温溶液缩聚

在N-甲基吡咯烷酮——氯化钙溶剂体系中,对苯二甲酰氯与对苯二胺低温溶液缩聚时,加入吡啶类添加剂,可以提高聚对苯二甲酰对苯二胺的分子量。本文讨论了不同结构的添加剂,添加剂的用量、添加方式、氯化钙含量及其与吡啶的关系、单体配比、单体浓度等因素对聚合体对数比浓粘度的关系,存在一个较佳的反应条件区域。当氯化钙含量在7—10％时,只要加入少量添加剂,就能大幅度地提高聚合体的粘度。     

Identification of swelling-activated Cl<Superscript>-</Superscript> current in rabbit cardiac Purkinje cells

The presence and functional role of the swelling-activated Cl^- current (I_Cl(swell)) in rabbit cardiac Purkinje cells was examined using patch-clamp methodology. Extracellular hypotonicity (210 or 135 mOsm) activated an outwardly rectifying, time-independent current with a reversal potential close to the calculated Cl^- equilibrium potential (E_Cl). The magnitude of this current was related to tonicity of the superfusate. The current was blocked by 0.5 mM 4,4-diisothiocyanostilbene-2,2-disulfonic acid (DIDS). These features are comparable to those of I_Cl(swell) found in sinoatrial nodal, atrial, and ventricular myocytes. I_Cl(swell) activation at 210 and 135 mOsm depolarized the resting membrane potential with 6 and 10 mV and shortened the action potential by 18 and 33%, respectively. DIDS partially reversed I_Cl(swell)-induced action potential changes. We conclude that I_Cl(swell) is present in Purkinje cells and its activation leads to action potential shortening and resting membrane potential depolarization, both of which can promote the development of reentrant arrhythmias.Received 20 January 2004; received after revision 17 February 2004; accepted 25 February 2004