1,5-二(2-羟基-5-氯苯)-3-氰基甲(鐕)分光光度法测定微量锗

研究了在十六烷基三甲基溴化铵存在下,1,5-二(2-羟基-5-氯苯)-3-氰基甲(鐕)(HCPCF)与锗(Ⅳ)发生显色反应的条件,建立了新的测定微量锗(Ⅳ)的高灵敏度分光光度法.实验结果表明,试剂与锗(Ⅳ)在pH 10.0的Na2B4O7-NaOH缓冲介质中形成稳定的蓝色络合物,其组成比为4∶1,络合物的最大吸收峰在632 nm波长处,表观摩尔吸光系数为2.7×105L·mol-1·cm-1.锗(Ⅳ)浓度在0.002～0.32μg/mL范围内符合比尔定律,检出限为0.80 mg/mL.经二乙基二硫代氨基甲酸钠-四氯化碳(DDTC-CCl4)萃取分离锌的干扰后,用于锌精矿中微量锗的测定,回收率在103.7%～104.6%之间,相对标准偏差(n=6)小于3%.     

4-(2-吡啶偶氮)间苯二酚固相萃取分光光度法测定痕量铂

研究了4-(2-吡啶偶氮)间苯二酚与铂(Ⅳ)的显色反应,建立了一个测定铂的光度分析新方法。在pH5.0的醋酸-醋酸钠缓冲介质中,溴化十六烷基三甲基铵(CTMAB)存在下,4-(2-吡啶偶氮)间苯二酚与铂(Ⅳ)反应生成摩尔比为2∶1稳定络合物,该络合物可用阳离子交换树脂固相萃取柱富集,吸附柱上富集的络合物用乙醇洗脱后用分光光度法测定。分离后的测定液中,络合物最大吸收波长为490nm,表观摩尔吸光系数ε=1.22×105L·mol-1·cm-1,铂(Ⅳ)含量在0～1.6μg/mL内符合比尔定律,相关系数r=0.9978,对30余种共存离子进行试验,结果表明,大多数常见离子不干扰测定。方法用于合金、矿石、粉煤灰等样品中铂的分析,相对标准偏差小于5.1%,加标回收率在96%～105%之间。     

2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸与锌显色反应的研究

研究了显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸(CTZDBA)与锌的显色反应。试剂与Zn2+在pH8.0的NH3.H2O-NH4Cl缓冲溶液中形成紫红色络合物,组成比为n(Zn2+)∶n(CTZDBA)=1∶2。络合物的最大吸收波长为545 nm,表观摩尔吸光系数ε=4.13×104L.mol-1.cm-1,Zn2+质量浓度在0.08~0.8 mg/L范围内符合比尔定律,检出限为1.57×10-8g/mL。方法不经分离直接测定镁合金和铝合金样品中微量锌,测定结果与认定值相符。     

5-(对羧基苯偶氮)-2-甲基-8-羟基喹啉固相萃取光度法测定金

根据新试剂5-(对羧基苯偶氮)-2-甲基-8-羟基喹啉(CPAQ)与金的显色反应及Sep-Pak(R)C18固相萃取小柱对显色络合物的固相萃取,建立了一种测定痕量金的新方法.在pH为5.0～6.3的柠檬酸氢二钠-氢氧化钠缓冲介质中,在Tween-80存在下,金与CPAQ发生反应形成1:1的稳定络合物.该络合物可用Sep-Pak(R)C18固相萃取小柱富集;小柱上富集的络合物用乙醇洗脱后,用分光光度法测定.在富集后的测定液中,络合物最大吸收波长为490nm ,摩尔吸光系数ε=2.53×105L/(mol·cm),Au3 质量浓度在0.1～1.2μg/ml范围内符合比尔定律.该方法用于测定矿样中微量金,结果令人满意.     

1-(2-吡啶偶氮)-2-萘酚光度法测定钒钛磁铁矿中痕量镓

利用1-(2-吡啶偶氮)-2-萘酚(PAN)与镓反应生成红色络合物的特性,建立了光度法测定钒钛磁铁矿中镓的方法。实验表明:于25 mL比色管中,依次加入2.0 mL KHP-HCl缓冲溶液(pH 3.2)、4.0 mL 0.5 g/L PAN溶液、3.0 mL 95%乙醇,用水定容后反应10 min,用1 cm比色皿,于545 nm处采用分光光度法进行测定,镓的质量浓度在0.05～3 μg/mL范围内符合比尔定律,方法检出限为0.033 μg/mL,表观摩尔吸收系数ε=3.0×10⁴ L·mol^-1·cm^-1。将GBW 07226a钒钛磁铁矿精矿一号和GBW 07224钒钛磁铁矿原矿一号样品经氢氧化钠和过氧化钠碱熔、水浸取、过滤、酸化还原铁等步骤后,采用乙酸丁酯萃取、水反萃取,使镓与大量基体元素分离,再采用方法对样品中痕量镓进行测定,结果与认定值一致,相对标准偏差(RSD,n=3)小于15%。     

2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺与钯显色反应的研究及其应用

探讨了2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺(5-I-PADMA)与钯(Ⅱ)的显色反应。实验表明,在0.6 mol/L高氯酸介质中,5-I-PADMA与钯(Ⅱ) 反应形成摩尔比为1∶1的蓝色稳定络合物,该络合物最大吸收峰位于613 nm处。钯(Ⅱ)含量在0~0.6 μg/mL范围内符合比尔定律,线性回归方程为△A=0.828 4 ρ(μg/mL)- 0.001 6,相关系数r=0.999 9,表观摩尔吸光系数为8.82 × 10⁴ L·mol^-1·cm^-1。方法应用于钯分子筛和矿样中钯的测定,结果与原子吸收光谱法一致,相对标准偏差(n=6)为1.2%～1.4%。     

1-(2-吡啶偶氮)-2-萘酚分光光度法测定硫酸阳极氧化液中铜

研究了铜与1-(2-吡啶偶氮)-2-萘酚(PAN)的显色反应,建立了测定硫酸阳极氧化液中铜的新方法。以TritonX-100为增溶增敏剂,明胶作稳定保护剂,在酸性条件下Cu-PAN络合物稳定保持在水相中,直接进行光度分析。该络合物在558nm处有最大吸收峰,其表观摩尔吸光系数ε=2.25×104L.mol-1.cm-1。方法检出限为0.028μg/mL,线性范围为0～3.2μg/mL,用于测定硫酸阳极氧化液中的铜,加标回收率为98.2%～105.6%,相对标准偏差≤0.34%。     

4-羟基萘-1-亚甲基若丹宁固相萃取光度法测定钯的研究

根据4-羟基萘-1-亚甲基若丹宁(HNR)与钯的显色反应及C18固相萃取小柱对显色络合物的固相萃取,建立了一种测定钯的方法。在pH为3.5的HAc-NaAc缓冲介质中,在吐温-80存在下,HNR与钯反应生成2∶1稳定络合物;该络合物可被C18固相小柱萃取富集,用乙醇(内含2%乙酸)洗脱后,采用光度法测定;在乙醇介质中,体系λmax=520nm,ε=8.61×104L/(mol·cm),钯质量浓度在0.01～2.0mg/L范围内符合比尔定律。该方法用于钯的测定,结果令人满意。     

1,5-二(2-羟基-5-磺酸基苯)-3-氰基甲(月无无白)催化褪色光度法测定微量过氧化氢

在Britton-Robinson缓冲溶液中,Mn2 催化过氧化氢氧化1,5-二(2-羟基-5-磺酸基苯)-3-氰基甲■(DSPCF)褪色反应,褪色反应程度与过氧化氢的量在一定范围内呈线性关系,据此建立了测定过氧化氢的分光光度法。方法的线性范围是0～1.25μg/mL,表观摩尔吸光系数ε=2.3×104L.mol-1.cm-1。已用于雨水中微量过氧化氢的测定,相对标准偏差为5.50%,平均加标回收率为98%。     

以2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺作螯合剂浊点萃取-激光热透镜光谱法测定水中痕量钴

钴是生命体必需的微量元素,研究建立水样中钴的测定方法具有重要意义。在pH 5.0的醋酸-醋酸钠缓冲介质中,于60℃水浴中加热10min, 螯合剂2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-PADMA)与钴(II)反应生成配位比为2∶1的疏水性螯合物Co(II)-5-Br-PADMA,其最大吸收波长位于611nm,用非离子表面活性剂TritonX-114为萃取剂进行浊点萃取(CPE),将该疏水性螯合物萃取到表面活性剂胶束相中,在相分离之后,以0.45mL 2mol/L HCl-乙醇溶液溶解胶束相,转入光程为5mm的自制石英吸收池中,以单模He-Ne激光器(λ=632.8nm)做激发和探测光束进行热透镜光谱法(TLS)测定,建立了浊点萃取-激光热透镜光谱法(CPE-TLS)测定超痕量钴的方法。在优化条件下,热透镜光谱信号强度与钴(II)质量浓度在0.40~6.0ng/mL范围内呈良好的线性关系,相关系数为0.9978,检出限为0.05ng/mL。按富集前后溶液体积比值计算其浓缩因子为22。将实验方法用于湖水和温泉水中钴含量的测定,结果的相对标准偏差(RSD,n=6)小于4%;结果与电感耦合等离子体质谱法(ICP-MS)基本一致;加标回收率在96%~101%之间。     

Synthesis and biological investigations of 1-(tetrahydropyran-2'-yl)- and 1-(tetrahydrofuran-2'-yl)benzimidazoles and 1/2-(tetrahydropyran-2'-yl)- and 1/2-(tetrahydrofuran-2'-yl)benzotriazoles

Sets of benzimidazole and benzotriazole derivatives bearing on position 1 or 2 a tetrahydrofuranyl or tetrahydropyranyl moieties were prepared through the addition of the suitable benzazoles on 2,3-dihydrofuran and 3,4-dihydro-2H-pyran. The reactions were carried on either without solvent or in carbon tetrachloride solution. In the last case some peculiar chlorinated side products were isolated and characterized. Twenty compounds were screened for in vitro antitumoral and anti-HIV-1 activities and found poorly active or completely inactive. On the other hand several compounds exhibited good tracheal relaxant activity in vitro; compound 8, 11, 16, 24 and 26 resulted more active than theophylline in this test, while compound 11 was comparable to amrinone till the concentration of 3 micrograms/ml. Finally, compound 5 resulted endowed with a strong diuretic and saluretic activity at the dose of 3 mg/Kg, thus representing a new lead for discovering new diuretic agents.     

CeO2对不锈钢基SiO2-BaO-Al2O3-Cr2O3陶瓷涂层性能的影响

采用高温熔烧法于1Cr18Ni9Ti不锈钢基材表面制备掺CeO2的SiO2-BaO-Al2O3-Cr2O3陶瓷涂层,研究了不同含量CeO2对涂层的抗氧化性、抗热震性和硬度的影响。研究结果表明,含CeO2的不锈钢基SiO2-BaO-Al2O3-Cr2O3陶瓷涂层能有效阻止不锈钢基体的氧化增重,提高涂层的抗热震性能及硬度。本实验条件下,CeO2含量2.8%时,涂层具有最好的抗氧化性能和抗热震性能。     

Texture and residual strain in two SiC/Ti-6-2-4-2 titanium composites

Residual strain and texture variations were measured in two titanium matrix composites reinforced with silicon carbide fibers (Ti/SiC) of similar composition but fabricated by different processing routes. Each composite comprised a Ti-6242 α/β matrix alloy containing vol 35 pct continuous SiC fibers. In one, the matrix was produced by a plasma sprayed (PS) route, and in the other by a wiredrawn (WD) process. The PS and WD composites were reinforced with SCS-6 (SiC) and Trimarc (SiC) fibers, respectively. The texture in the titanium matrices differed significantly. The titanium matrix for the PS material exhibited random texture pre and post fabrication of the composite. For the WD material, the starting texture of the monolithic titanium matrix was ≈17 times random, but after consolidation into composite form, it was ≈6 times random. No significant differences were noted in the fiber-induced matrix residual strains between the composites prepared by the two procedures. However, the Trimarc (WD) fibers recorded higher (≈1.3 times) compressive strains than the SCS-6 (PS) fibers. Stresses and stress balance results are reported. Plane-specific elastic moduli, measured in load tests on the unreinforced matrices, showed little difference. This article is based on a presentation made in the Symposium “Mechanisms and Mechanics of Composites Fracture” held October 11–15, 1998, at the TMS Fall Meeting in Rosemont, Illinois, under the auspices of the TMS-SMD/ASM-MSCTS Composite Materials Committee.     

Texture and residual strain in two SiC/Ti-6-2-4-2 titanium composites

Residual strain and texture variations were measured in two titanium matrix composites reinforced with silicon carbide fibers (Ti/SiC) of similar composition but fabricated by different processing routes. Each composite comprised a Ti-6242 α/β matrix alloy containing vol 35 pct continuous SiC fibers. In one, the matrix was produced by a plasma sprayed (PS) route, and in the other by a wiredrawn (WD) process. The PS and WD composites were reinforced with SCS-6 (SiC) and Trimarc (SiC) fibers, respectively. The texture in the titanium matrices differed significantly. The titanium matrix for the PS material exhibited random texture pre and post fabrication of the composite. For the WD material, the starting texture of the monolithic titanium matrix was ≈17 times random, but after consolidation into composite form, it was ≈6 times random. No significant differences were noted in the fiber-induced matrix residual strains between the composites prepared by the two procedures. However, the Trimarc (WD) fibers recorded higher (≈1.3 times) compressive strains than the SCS-6 (PS) fibers. Stresses and stress balance results are reported. Plane-specific elastic moduli, measured in load tests on the unreinforced matrices, showed little difference. This article is based on a presentation made in the Symposium “Mechanisms and Mechanics of Composites Fracture” held October 11–15, 1998, at the TMS Fall Meeting in Rosemont, Illinois, under the auspices of the TMS-SMD/ASM-MSCTS Composite Materials Committee.     

Biochemical basis for a cholesterol-lowering activity of 2-[2"-(1",3"-dioxolane)]-2-methyl-4-(2'-oxo-1'-pyrrolidinyl)-6- nitro-2H-1-benzopyran (SKP-450), a novel antihypertensive agent

Administration (p.o.) of SKP-450, 2-[2"-(1",3"-dioxolane)]-2-methyl-4-(2'-oxo-1'-pyrrolidinyl)-6-nitro-2H- 1-benzopyran, a novel antihypertensive agent, to hypercholesterolemic Syrian hamsters led to a significant reduction in plasma lipids in a dose-dependent manner, i.e., a 10.8% to 29% reduction in low-density lipoprotein cholesterol at doses of 0.3 to 10 mg/kg of SKP-450. SKP-450 was found to specifically inhibit the hepatic microsomal lanosterol 14alpha-methyl demethylase (14alpha-DM) in a competitive manner (Ki:2.65 microM). Furthermore, a dose-dependent decrease in the 14alpha-DM activity by SKP-450 parallelled the cholesterol synthetic rate in vitro in both the rat hepatic S10 fractions (supernatants at 10,000 g; IC50:20 microM) and Chinese hamster ovary cells (IC50:23 microM). However, this phenomenon was not seen in AR45 cells, which are deficient in 14alpha-DM, suggesting that 14alpha-DM is the major target for the inhibitory action of SKP-450 in regard to cholesterol biosynthesis.     

The free energies of mixing of melts in the systems 2FeO-SiO2-2MnO-SiO2 and 2.33FeO-TiO2-2.33MnOTiO2

The free energies of mixing in melts in the system 2FeO · SiO₂-2MnO · SiO₂ at 1450°C and the system 2.33FeO · TiO₂-2.33MnO · TiO₂ at 1475°C have been obtained from measurement of the equilibrium Mn + FeO = Fe + MnO established between the melts and ironmanganese foils. Both systems exhibit ideal silicate mixing. The phase diagram for the system 2FeO-SiO₂-2MnO ·SiO₂ is calculated.     

Synthesis and biological investigations of 2-(tetrahydropyran-2'-yl) and 2-(tetrahydrofuran-2'-yl)benzimidazoles

A set of benzimidazole derivatives bearing on position 2 a tetrahydropyranyl or tetrahydrofuranyl residue was prepared and tested for antitumoral, anti HIV-1 and other pharmacological activities. While the anti-HIV activity was completely lacking, moderate antitumoral activity was found in a few compounds; particularly the 5,6-dichloro-2-(tetrahydropyran-2-yl)-benzimidazole (8) was able to inhibit the growth of 19 cell lines of humane tumors at near micromolar concentration. On the other hand compounds 4, 6-8 and 10 exhibited significant tracheal relaxant activity in vitro at concentration 3-10 micrograms/ml, thus resulting superior to theophylline and comparable to amrinone.     

2-(2-咪唑偶氮)-5-二甲氨基苯甲酸分光光度法测定铜

研究了新显色剂2-(2-咪唑偶氮)-5-二甲氨基苯甲酸(IZDBA)与铜的显色反应。结果表明,在pH 4.0的HAc-NaAc缓冲溶液中,IZDBA与Cu(Ⅱ)形成稳定的摩尔比为2∶1的紫红色络合物,其最大吸收波长为600 nm,表观摩尔吸光系数为3.62×104L.mol-1.cm-1,Cu(Ⅱ)质量浓度在0.08~0.8 mg/L范围内符合比尔定律。本方法可不经分离直接测定铝合金和镁合金样品中微量的铜,测定结果与认定值相符。     

新显色剂2-(2-咪唑偶氮)-5-二乙氨基酚光度法测定铁(Ⅲ)

研究了新显色剂2-（2-咪唑偶氮）-5-二乙氨基酚（简称IZAPN）与Fe     

Electrical properties of phases in the ZrO2 - Y2O3 - La2O3 system

An investigation was made of the electrical properties of phases with the cubic fluorite, pyrochlor, and C-Y₂O₃ structures, and the tetragonal ZrO₂ structure (T-ZrO₂) in the ternary system ZrO₂ - Y₂O₃ - La₂O₃. For comparison, the electrical conductivity of a number of specimens with the fluorite structure in the binary system ZrO₂ - Y₂O₃ and with the pyrochlor structure in the ternary system HfO₂ - Y₂O₃ - La₂O₃ was also studied. The specimens were prepared from nanocrystalline powders synthesized by the hydrolysis of zirconium salts in an acid medium at high temperatures. Conductivity was measured over the range 300–950°C in air. It was shown that phases with the fluorite and T-ZrO₂ structures in the investigated systems possess the highest electrical conductivities. Translated from Poroshkovaya Metallurgiya, Nos. 3/4(412), pp. 40–46, March–April, 2000.