高铁试剂作萃取剂的PEG2000液-液萃取的研究

在PEG2000-(NH_4)_2SO_4—H_2O体系中,用高铁试剂作萃取剂,研究了Fe(Ⅲ)、U(Ⅵ)、V(Ⅴ)等金属离子络合物在两相的分配,借控制酸度和加入掩蔽剂的方法,实现了Fe(Ⅲ)—U(Ⅵ),V(Ⅴ)—U(Ⅵ),Fe(Ⅲ)—V(Ⅴ)的定量萃取分离。利用加入表面活性剂的方法,探讨了PEG相的萃取机理。     

Tween-80-水杨基荧光酮-硫酸铵体系液液萃取分离钼的研究

以水杨基荧光酮 (SAE)作萃取剂 ,Tween 80作析相剂 ,在硫酸铵存在下 ,系统地研究了金属络合物在该体系中的液 液两相间的分配行为 ,实验表明 ,在pH0.0～ 7.0时 ,Mo(Ⅵ)均保持很高的萃取率 ,而Fe(Ⅲ) ,Zn(Ⅱ) ,Cd(Ⅱ) ,Co(Ⅱ) ,Cu(Ⅱ) ,Ni(Ⅱ) ,Mn(Ⅱ)在 pH3～ 4时萃取率较低 ,借控制酸度的方法实现了Mo(Ⅵ)与Fe(Ⅲ) ,Zn(Ⅱ) ,Cd(Ⅱ) ,Co(Ⅱ) ,Cu(Ⅱ) ,Ni(Ⅱ) ,Mn(Ⅱ)等常见离子的定量分离 ,获得了满意的     

聚氧乙烯十二烷基醚-盐-水-液-固萃取体系

研究了聚氧乙烯十二烷基醚(PLE)水溶液在无机盐存在下的分相条件;讨论了偶氮氯膦(CPA)等螯合剂及U(Ⅵ)、La(Ⅲ)、Zr(Ⅳ)、Sc(Ⅲ)等金属离子的螯合物在PLE固相中的萃取行为。用控制酸度与加掩蔽剂的方法实现了U(Ⅵ)—La(Ⅲ)、U(Ⅶ)—Zr(Ⅳ)的定量萃取分离。     

仲辛基苯氧乙酸萃取铜(Ⅱ)、钴(Ⅱ)、镍(Ⅱ)的机理

采用溶剂萃取法 ,研究了一种新型萃取剂———仲辛基苯氧乙酸 (CA -12 )氨化后从盐酸介质中萃取Cu(Ⅱ )、Co(Ⅱ )、Ni(Ⅱ )的机理。确定了萃取反应的机理、萃合物的组成及萃取反应的平衡常数。并经红外光谱确证了氨皂化的CA -12从盐酸介质中萃取Cu(Ⅱ )、Co(Ⅱ )、Ni(Ⅱ )的机理     

铕-M(Zn~(2+),Ca~(2+)等)-均苯四甲酸的合成及荧光光谱性质

合成了均苯四甲酸（PMA）、铕离子（Eu(3+)和常见Ⅱ族离子（Mg~(2+)，Ca~(2+)Sr(2+)、Ba(2+)、Zn(2+)）形成的系列配合物。研究了它们的红外和荧光光谱，讨论了Zn~(2+)含量对配合物发光强度的影响及敏化发光机理，得到了具有潜在应用价值的鲜红色发光材料Eu-Zn-PMA配合物Zn~(2+3+)=4：1）。     

一类二阶多时滞泛函微分方程多个周期解的存在性

利用重合度理论获得了二阶多时滞泛函微分方程xw(t)+f(t,x(t-τ1(t),x(t-τ2(t)))(x'(t))n+f(x(t))·x'(t)+a(t)x2(t-τ3(t))+b(t)x(t-τ3(t))=p(t)(n≥2)多个周期解的存在性,得到了这类方程至少存在2个周期解的结论.     

铋(Ⅲ)-8-羟基喹哪啶体系极谱行为和表面活性剂增敏机理

本文在研究了铋(Ⅲ)—8-羟基喹哪啶(8-OXQ)体系极谱行为的基础上,详细研究了阴离子表面活性剂十二烷基苯磺酸钠(SDBS)对该体系示波极谱电流(ip)增敏机理。建立了测定高温合金中痕量(10~(-5)—10~(-4)％)铋的高灵敏新方法,检出限为0.4ng/ml(1.9×10~(-9)mol/L),结果可靠、满意。文中对比了Bi(Ⅲ)和8-羟基喹啉(8-OX)及其衍生物体系结合物峰电流以及Bi(Ⅲ),Pb(Ⅱ)-8-OXQ体系和Cu(Ⅱ),Cd(Ⅱ),Zn(Ⅱ)—乙二胺体系被SDBS增敏效应,然后提出     

巯基乙酰胺树脂用于金、铂的分析研究

本文以大孔PVC(聚氯乙烯)为原料,合成了含有巯基乙酰胺基团的螯合树脂,对树脂吸附Au(Ⅲ)、Pt(Ⅳ)的条件进行了研究,测定了某水样中Au(Ⅲ)、Pt(Ⅳ)的含量,回收率均在95％以上。     

Eu(bpy)2(NO3)3(H2O)2/Nafion修饰于金电极上的电化学发光性质研究

本文合成了铕-联吡啶的二元配合物Eu(bpy)2(NO3)3(H2O)2,用元素分析、红外及紫外光谱对配合物进行了表征.采用循环伏安法,研究了用Nafion将Eu(bpy)2(NO3)3(H2O)2修饰于金电极上的电化学发光行为.讨论了介质、pH对该体系电化学发光性质的影响,推测了Eu(bpy)2(NO3)3(H2O)2电化学发光的机理.结果表明:在没有共反应试剂存在的条件下,Eu(bpy)2(NO3)3(H2O)2在pH 8.0的硼砂缓冲溶液中可以产生较强的电化学发光,其发光体可能为Eu*(bpy)2(NO3)3(H2O)2.     

一种初值修正的非等间距GM(1,1)模型及其等价模型

通过为白化微分方程是{dx(1)(t)/dt+ax(1)(t)=u x(1)(k1)=x(0)(k1)的非等间距GM(1,1)模型选取修正初值x(0)(k1)+β,建立了白化微分方程为{dx(1/dt+ax(1)(t)=u x(1)(k1)=x(0)(k1)=x(0)(k1)+β的一种新的初值修正非等间距GM(1,1)模型,从而拓广了非等间距GM(1,1)模型的形式.然后证明了修正初值为经x(0)(k1)+β的新的非等间距GM(1,1)模型与修正初值为ax(0)(k1)的非等间距GM(1,1)模型等价.最后,通过实例验证了该模型的可行性与实用性.这些结论不仅揭示了两种基于初值修正的非等间距GM(1,1)模型之间的本质联系,而且为进一步应用非等间距GM(1,1)模型提供了更大的选择空间.     

Cys860 in the extracellular domain of insulin receptor beta-subunit is critical for internalization and signal transduction

The C860S mutation (IRC860S) in the extracellular domain of the insulin receptor beta-subunit has previously been shown to result in an inhibition of insulin receptor internalization. The present work aims at further dissecting the consequences of this mutation not only on insulin receptor internalization, but also on the signaling of the receptor. Following transfection of Chinese hamster ovary (CHO) cells with insulin receptors with the C860S mutation (CHO-IRC860S) and quantitative electron microscopic analysis of [125I]insulin localization in these cells, the inhibition of receptor internalization appears to be due to an inhibition of the lateral translocation of the receptor from microvilli to nonvillous domains of the cell surface. At 37 C, insulin-stimulated insulin receptor substrate-1 (IRS-1) phosphorylation is inhibited by 50% in CHO-IRC860S, whereas Shc phosphorylation remains unaffected. The inhibition of IRS-1 phosphorylation is still present when experiments are conducted at 4 C, a temperature at which insulin receptor internalization is prevented, suggesting that the defect in IRS-1 phosphorylation is not due to the reduced internalization of the receptor. In terms of biological effects, the mutation has negative consequences on insulin-stimulated c-fos expression and DNA synthesis as well as on glycogen synthase activity. Eventually, the events observed are specific for Cys860, as individual substitution of the two more proximal Cys residues (795 and 872) to Ser is not accompanied by any change in either insulin-induced insulin receptor internalization or IRS-1 phosphorylation. Thus, the present analysis of CHO-IRC860S 1) reveals that insulin receptor surface redistribution is not solely dependent on receptor autophosphorylation, 2) emphasizes that IRS-1 phosphorylation is not dependent on receptor internalization and can be triggered from microvilli, and 3) stresses divergent aspects between two of the major signaling pathways of the insulin receptor.     

模具及温度对1 500 MPa级热成形钢组织性能的影响

采用光学显微镜、扫描电镜,以及单向拉伸试验等手段,研究了模具形状及加热温度对1 500 MPa级热成形钢组织性能及其回弹性的影响。结果表明,初始冷轧钢板组织主要是铁素体和珠光体。随着加热温度的升高,热成形后钢板的强度显著升高后逐渐降低,加热温度860 ℃时性能较优。由于U型件在热成形时发生变形,侧面的抗拉强度比底部的低,在860 ℃时的回弹最小,平均为16.6°。在加热温度860 ℃后采用U型模具的热成形钢的各项性能较优。      

热处理工艺对9Cr钢组织与力学性能的影响

利用热膨胀试验研究了9Cr钢随冷却速度变化的相变行为,设定奥氏体化温度分别为860和1000℃,利用 OM、SEM、TEM、XRD和室温拉伸对比研究不同热处理温度下9Cr钢的显微组织及力学性能.研究表明：随着冷却速度增加,9 Cr 钢发生铁素体/珠光体相变、贝氏体相变和马氏体相变,其中马氏体相变临界冷速为1.6℃/s;860℃热处理后9Cr钢的显微组织为板条贝氏体/马氏体和少量等轴铁素体,并有4％的残余奥氏体;奥氏体化温度升至1000℃后,奥氏体晶粒尺寸增加,9Cr 钢中铁素体几乎消失,板条特征更加明显,力学性能与860℃热处理后基本相同,均达到 HL级抽油杆钢的要求,说明9Cr钢具有较宽的工艺窗口.     

The impact of routine obstetric ultrasonographic screening in a low-risk population

OBJECTIVES: Our goal was to develop a framework for evaluating the current controversy regarding routine obstetric ultrasonography in a population of low-risk pregnancies. STUDY DESIGN: A retrospective chart review was performed for all low-risk pregnancies from a single obstetric practice during 1990 to 1994, to determine the accuracy of screening ultrasonography for fetal anomalies. All patients received a routine ultrasonographic examination at 18 to 20 weeks' gestation. Neonatal records for all patients were evaluated for the presence of both major and minor anomalies. The data were analyzed with attention to the classification of anomalies (all anomalies vs major anomalies, detectable vs nondetectable). RESULTS: A total of 860 fetuses in 854 pregnancies were evaluated. Anomalies were present in 5.35% (46/860); these were major anomalies in 1.16% (10/860) and minor anomalies in 4.19% (36/860). The sensitivity, specificity, and positive and negative predictive values for the diagnosis of all anomalies were 8.7%, 99.9%, 80%, and 95.7%, respectively. However, if only major anomalies detectable by ultrasonography are included, these values become 75%, 100%, 100%, and 99.9%, respectively. There was one false-positive diagnosis not affecting outcome, a small ventriculoseptal cardiac defect. Postnatal ascertainment of anomalies was excellent, as determined by an incidence of ventriculoseptal defects of 1 in 120. CONCLUSION: Distinguishing between major and minor anomalies and between ultrasonographically detectable versus nondetectable anomalies is essential in the evaluation of the diagnostic accuracy of screening ultrasonography. Any comparisons of studies examining the effectiveness of prenatal screening for congenital anomalies with ultrasonography should use the same outcome: major anomalies identifiable by ultrasonography.     

Effect of Thermomechanical Treatment Temperature on Structure and Properties of CFB/M Ultra-High Strength Steel

Modified CCT diagram of carbide-free bainite-martensite(CFB/M)ultra-high strength steel was established by applying controlled cooling of small samples.In addition,the influence of thermomechanical treatment temperature on the structure and properties was discussed.The experimental results showed that when deformed at 860℃ and below,ferrite transformation occurred due to strain.With the decrease of ausforming temperature,the quantity of ferrite increased and strength and toughness were deteriorated.Therefore,certain information was provided for optimizing technical parameter of ausforming process:firstly,the thermomechanical treatment temperature should not be lower than 860℃ in order to avoid ferrite formation induced by deformation;secondly,rapid cooling rate is also significant after deformation in order to avoid ferrite precipitation during subsequent cooling stage.     

16MnCr5钢形变热处理相变和显微组织研究

在热模拟机上测试了16MnCr5钢经1200℃加热的未变形奥氏体、在860℃经50％压缩变形奥氏体的CCT曲线和维氏硬度,研究了其相变组织。结果表明：未变形奥氏体以0.025℃/s连续冷却时和在860℃变形的未再结晶奥氏体以0．2℃／s连续冷却时及1100℃变形的再结晶奥氏体分别以0．05℃／s连续冷却和快冷至660℃等温退火时均得到多边形铁素体＋环光体组织。     

几种螯合树脂在模拟的钴电解液中吸附铜的性能研究

对比研究了三种亚胺二乙酸螯合树脂D850、D463、D751、一种氨膦酸基螯合树脂D860及一种氨甲基吡啶树脂CuWRAM在模拟的钴电解液的硫酸盐体系、氯盐体系及硫酸盐-氯盐混合体系中吸附铜的性能.结果表明:五种树脂均在料液pH较高的条件下对铜的吸附容量最大,其中以D860的对铜的交换容量最大,以CuWRAM对铜的交换...     

热处理工艺对40CrMnMo钢低温冲击韧性的影响

通过不同的热处理制度:800、820℃低温淬火+600℃回火,880℃+860℃两次淬火+600℃回火和860℃一次淬火+600℃回火,对40CrMnMo钢进行热处理试验,并研究了三种热处理工艺对40CrMnMo试验钢组织和性能的影响。结果表明,三种热处理工艺的试验钢抗拉强度相近(936～951 MPa),组织为回火马氏体+铁素体,采用800、820℃低温淬火+600℃回火热处理工艺,试验钢的冲击功最高(65～69J)。     

Tempora mutantur, nos et mutamur in illis!

In March 1992, KAP investigation and HIV blood test were carried out for 860 drug users and 82 spouses in Ruili, Luxi, Longchuan of Yunnan Province, China. The results show that there were 285 IDUs (33.1%) among 860 drug users. Among 282 blood samples of IDUs, the HIV infection rate was 49.0%, highest in Ruili (81.8%, 63/77), then Longchuan (44.6%, 77/166), lowest in Luxi County (5.1%, 2/36). Twelve new HIV+ were found from 75 persons, who had been tested as HIV- in recent two years. Sixty-two blood samples were collected among 82 spouses of IDUs with HIV+, 6 were HIV+ (9.8%), with an increase of 6.7% comparing with results of the investigation two-years ago (3.1%, 2/64).