偶氮胂Ⅲ褪色光度法测定铬

在6mol·L~(_1)HNO_3介质中,Cr(Ⅵ)与偶氮胂Ⅲ进行氧化褪色反应,该褪色反应的表现摩尔吸光系数∑_(523nm)=3.7×10~5L·mol~(-1)·cm~(-1)。铬(Ⅵ)在0～1.8×10~(-4)g/L范围内符合比尔定律。本法用于土样中痕量铬的测定,结果满意。     

Investigation of Y_2O_3 Particle Doped on Superalloy by Laser Irradiation

Possibility to dope Y_2O_3 particles into the sur-face of superalloy sample by means of laserirradiation and the relationship betweenhomogeneity and laser irradiation parameters havebeen investigated.The results show that homoge-neous distribution of Y_2O_3 particles in melt-dopedregion can be obtained on a macro scale and thecontent of Y_2O_3 in the region can reach 2 wt-%when precoating powder quantity is 0.05g/cm~2,laser power density is selected as 1.76×10~4W/cm~2 and scanning speed 0.36m/min.     

偶氮氯膦——mA分光光度法测定钢样及食盐中钡

在pH9.0的NH_3—NH_4Cl缓冲溶液中,Ba(Ⅱ)与间乙酰基偶氮氯膦(CPAmA)生成紫蓝色络合物。络合物的最大吸收位于635nm。络合物的组成Ba(Ⅱ):CPAmA为1∶4,表现摩尔吸光系数ε_(max)=1.95×10~41·mol~(-1)·cm~(-1),钡(Ⅱ)含量在0-3.2×10~(-3)g/L范围内遵守比尔定律。本法用于测定钢样及食盐中的钡,结果满意。     

Textured Tl(1223)/Ag Tapes Prepared by Electrophoretic Deposition

The conventional powder-in-tube technique does not allow to produce textured Tl(1223) tapes. An electrophoretic deposition technique was used to produce uniform layers of controlled thickness on Ag substrates by a simple and reproducible procedure. A high degree of texture, comparable with the one generally observed for Bi-based tapes was obtained thanks to the appropriate grain morphology, by simply alternating deposition and uniaxial pressing. After annealing, critical current densities of 11'000 A/cm² were reached.     

分光光度法测定猪肾中的硒

在盐酸介质中3—3’二氨基联苯胺与硒反应生成黄色络合物,λ_(max)=420nm,ε=4×10~4L·mol~(-1)·cm~(-1),硒含量在0.5～50μg/25ml内符合比尔定律,本方法用于猪肾样品中硒的测定结果令人满意。     

Ti 离子注入 LiNbO_3表面损伤分析

本文分析了高能 Ti 离子注入 LiNbO_3后 x,y,z 三种不同切向的表面损伤分布及退火效应。x,y 切片表面损伤程度近乎无定形,Nb 原子迁移率 N_D/N=1;z 切片表面损伤仍未饱和,N_D/N=0.8。辐射损伤主要是大量 Nb 偏离晶格位置成为间隙原子,注入的 Ti 离子处于间隙位置—LiNbO_3结构中固有的空位,使晶格有微小的膨胀。注入后产生有大量的氧缺位,氧气氛中热退火可消除氧缺位,使位移原子恢复至原晶格位置,且大部分间隙位置上的 Ti 离子通过替代 Nb 或少数 Li 进入正规格点上,此处晶格有少许收缩;热处理后损伤的消除由注入层与衬底的界面处向外表面方向进行,需1000℃高温退火,晶格损伤才能获得明显的改善,氧气氛可防止氧缺位的增多。     

Thermoelectric properties and texture evaluation of Ca<Subscript>3</Subscript>Co<Subscript>4</Subscript>O<Subscript>9</Subscript> prepared by a cost-effective multisheet cofiring technique

Highly textured Ca₃Co₄O₉ thermoelectrics were fabricated by a so-called multisheet cofiring (MSC) technique in combination with the commonly practiced spark plasma sintering (SPS) technique. X-ray diffraction analysis revealed that the MSC technique significantly enhances the degree of texture compared with the conventional SPS technique. This was confirmed by microstructure analysis performed on polished and chemically etched specimens. The power factor and the thermoelectric figure of merit for the specimen produced by the MSC technique were estimated to be ~5.2 × 10⁻⁴ W/mK² and ~0.4, respectively, both of which are ~20% larger than those of the normally processed specimens. A comparative study of the thermoelectric properties, such as electrical resistivity and Seebeck coefficient, clearly demonstrated that texture mainly influences the electrical resistivity and consequently enhances the thermoelectric properties.     

Meso—四—(4—甲基,3—磺基苯基)卟啉分光光度法测定葡萄糖酸锌含量

本文研究了在抗坏血酸存在下TTPS_4与Zn(Ⅱ)的显色反应。结果表明:在PH为4.40的NaAc—HAc缓冲体系中,以抗坏血酸和吐温—60为辅助配位剂,在沸水浴中加热8分钟,Zn(Ⅱ)与TTPS_4即形成稳定的高灵敏度配合物,最大吸收波长位于430 nm,ε_(430)=5.5×10~5。Zn(Ⅱ)浓度在0～0.120μg/ml范围内遵守比耳定律。应用此法直接测定补锌口服液葡萄糖酸锌含量,结果满意。     

Effects of Sintering on the Microstructure and Critical Current Density of Ag-sheathed BiPbSrCaCuO Superconducting Tapes

The effects of sintering on the microstructure and the critical current density of Ag-sheathedBiPbSrCaCuO (2223) superconducting tapes prepared by the powder-in-tube technique were in-vestigated. The microstructure of oxide layer and the J_C at 77 K were strongly dependent on thesintering condition. The optimum sintering temperature, time and cooling rate to maximize J_C valueswere in the range about 840-850℃, 100-200 h and 50-100℃/h, respectively.     

溴麝香草酚蓝分光光度法测定短链季铵盐

本文研究了以氯仿萃取四乙基溴化铵与溴麝香草酚蓝的离子缔合物后,水相中溴麝香草酚蓝的吸光度与四乙基溴化铵浓度的关系。结果表明:在pH-6.0的NaH_2PO_4—Na_2HPO_4缓冲体系中,以氯仿萃取溴麝香草酚蓝和四乙基溴化铵形成的离子缔合物,水相中溴麝香草酚蓝的吸光度变化值与四乙基溴化铵含量呈线性关系。四乙基溴化铵浓度在4×10~(-5)～4×10~(-4)mol/L范围内符合比尔定律,线性方程为△A=7.40×10~3C—0.0054,r=0.999。应用此法直接测定膨润土有机化程度,结果满意。     

Beryllium Surface Modified by B Ion Implantation

Beryllium is implanted with 100 keV,2×10~(17) B/cm~2 and post-implanted sample isannealed at 650℃ for 1 h.Hardness measurementindicates that the hardness increases withimplantation and can further be modified bypost-implantation heat treatment.Profile measurement shows that implantationcauses contamination on the surface of beryllium.During annealing boron diffuses out of berylliumand carbon on surface diffuses into beryllium.Beryllium surface is modified by compositionchange and carbide formation.     

在表面活性剂OP存在下,用DDPBC分光光度法测定微量钼

本文研究了钼与6,7—二羟基—2,4—二苯基苯骈吡喃氯化物(简称 DDPBC),在 OP存在下的显色反应。测钼的摩尔吸光系数(ε)达到5.6×10~5。在弱酸性介质中,Mo(V1)与 DDPBC生成一种橙红色络合物,其组成比为1∶2(Mo∶DDPBC)。最大吸收峰在 532nm 处。在浓度0～12.0mg/10ml 范围内符合比尔定律。本法应用于簇合物中钼的测定时,结果满意。     

金属—PAN—S配合物的极谱研究——Ⅱ:Fe~(3+)—PAN—S—TEA—NH_3·H_2O—NH_4Cl体系配合吸附波

在NH_3·H_2O—NH_4Cl—三乙醇胺底液中Fe(Ⅲ)与PAN—S产生一灵敏的配合吸附波,峰电位在—0.50伏(vs.SCE)。峰电位与铁离子浓度在2.8×10~8～3.4×10~(-6)mol/L范围内线性良好,检出下限可达2.8×10~(-8)mol/L。该法用于乳粉、头发、血清等样品的测定,结果满意。     

分光光度法测定芦荟中铁含量的研究

本文研究了Fe(Ⅱ)—phen—CTMAB—酒石酸氢钾体系测定铁离子含量分光光度法,最大吸收波长515nm,Fe(Ⅲ)含量在0.5～8μg/ml内符合比耳定律,相关系数r=0.9995,摩尔吸光数ε=1.23×10~4L·mol~(-1)·cm~(-1).利用该方法测定库拉索芦荟含铁量,RSD小于0.54％(n=6),回收率98.1％～101.5％。     

新化学发光试剂氟磺酸9.10—二甲基吖啶测定钴的研究

研究了钴催化氟磺酸9.10-二甲基吖啶的化学发光特性。建立了测定Co~(2)的化学发光新方法。方法线性范围为1×10~(-10)～1×10~(-7)g/ml;检测限为5.0×10~(-11)g/mlCo~(2+)。测定5×10~(-9)g/ml Co~(2+)的相对标准偏差为6.0％。方法可应用于自来水、江水、池塘水中痕量钴的测定。     

己烷雌酚在玻碳电极上的电化学行为研究

本文采用了现代电化学分析方法系统研究了己烷雌酚在玻碳电极上的电化学行为。实验表明己烷雌酚在玻碳电极上的氧化是不可逆过程,在pH=6.0的磷酸盐缓冲介质条件下,利用微分脉冲伏安法研究了己烷雌酚定量分析方法,发现在1.5×10~(-6)-2.0×10~(-4)mol/L范围下,己烷雌酚的浓度与脉冲电流信号成线性关系,检出限是5.0×10~(-7)mol/L,相关系数为0.9913.回收率为98.5%(n=5),RSD为3.27%,日内及日间RSD分别为2.85% and 3.12%(n=5),对模拟血样中己烷雌酚含量进行了测定,方法简便、快速,结果令人满意。     

Electrical properties of HfTiO Gate Dielectric Ge MOS capacitors with wet-NO surface pretreatment

Surface pretreatments for preparing HfTiO/GeOxNy stack gate dielectric on n-Ge substrate have been investigated.Excellent performances of Al/HfTiO/GeOxNy /n-Ge MOS capacitor have been achieved with an equivalent oxide thickness of 1.44 nm,physical thickness of 7.2 nm,equivalent permittivity of ~ 35,interface-state density of 2.1×1011 eV-1cm-2,equivalent oxide charge of-1.96×1012 cm-2 and gate leakage current of 2.71×10-4 A/cm2 at Vg = 1 V.Experimental results also indicate that the wet NO pretreatment can l...     

聚鲁米诺膜修饰金电极上对苯二酚的电化学行为

在强酸性溶液中,鲁米诺能在金电极上电氧化聚合得到聚鲁米诺刚性膜,该膜有一对峰形良好的氧化还原峰。该聚鲁米诺膜修饰电极可用于电催化氧化对苯二酚。在0.5molL-1H2SO4溶液中,该修饰电极上对苯二酚氧化电流的线性范围为5.0×10-6~2.0×10-4molL-1。     

Ag基底织构和表面状况对YBCO薄膜性能的影响

采用MOD方法在三种不同织构和表面状态的Ag基底上制备了YBCO薄膜,研究了Ag基底的织构和表面状态对YBCO超导薄膜的影响.在真空中退火的Ag基底上沉积的YBCO薄膜仅有c轴取向,且薄膜表面有很多平行条纹,薄膜的连接性不好,J_c不高;在氩气气氛中退火的Ag基底上沉积的YBCO薄膜,具有很强的c轴取向和良好的面内织构,J_c相对较高为1.2×10⁴A/cm²;冷轧Ag基底沉积的YBCO薄膜织构没有氩气退火的Ag基底上的强,但薄膜的表面平整,连接性好,临界电流密度最高为1.5×10⁴A/cm².     

不同雷诺数下方柱绕流的数值模拟

在不同雷诺数条件下,对流体绕经方形柱体的流动进行了数值模拟,计算雷诺数分别为100,1×103,1×104和2.2×104.当Re=100时,直接采用N-S方程进行计算;当Re=1×103,1×104和2.2×104时,则引入k-ε湍流模型进行计算.应用Galerkin有限元法对控制方程进行离散和求解,利用分离时间步长法处理控制方程中的非线性项.模拟计算得出了在不同雷诺数下的卡门涡街脱落形态.方柱后尾涡的形态会随雷诺数的变化而产生一定的变化.当雷诺数较低时,尾涡会拖得比较长,随着雷诺数的增加,尾涡长度会随之缩短.计算得到了方柱的受力系数和Strouhal数.将计算结果与文献上的实验和计算结果进行了比较,两者吻合较好.