2-(2-喹啉偶氮)-5-二甲氨基酚固相萃取光度法测定锌的研究

研究了新试剂2-(2-喹啉偶氮)-5-二甲氨基酚(QADMAP)与锌的显色反应,在pH 8.5的硼酸-氢氧化钠缓冲介质中,Triton X-100存在下,QADMAP与锌反应生成2∶1稳定络合物,体系最大吸收波长λ_max=590 nm,摩尔吸光系数ε=1.22×105 L·moL-1·cm-1,样品中的锌用强阴离子交换固相萃取柱固相萃取预分离和富集后用该方法测定,结果令人满意。     

1-（4-硝基苯基）-3-（4,6-二甲基-2-嘧啶）-三氮烯的合成及其与锌（Ⅱ）的显色反应

合成了一种新显色剂1-(4-硝基苯基)-3-(4,6-二甲基-2-嘧啶)-三氮烯(简称NPDMPMT),并研究了在非离子型表面活性剂Triton X-100存在下,于pH为11.0的Na2B4O7-NaOH缓冲溶液中与锌(Ⅱ)的显色反应.结果表明.Zn与试剂NPDMPMT形成1:2的橙黄色配合物,在456nm处有一最大正吸收,在530nm处有一最大负吸收,建立以530nm为参比波长,456nm为测量波长的双峰双波长测定法,其表观摩尔吸光系数为3.16×105L·mol-1·cm-1,锌(Ⅱ)浓度在0-8.0μg/25mL范围内符合比耳定律.方法用于人发中微量锌的测定,结果令人满意.     

1-偶氮苯-3-(5-氯-2-吡啶)-三氮烯的合成及与锌的显色反应

合成了新显色剂1-偶氮苯-3-(5-氯-2-吡啶)-三氮烯.在表面活性剂OP存在下,pH为10.5-11.5的Na2B4O7-NaOH缓冲溶液中,新显色剂1-偶氮苯-3-(5-氯-2-吡啶)-三氮烯与锌发生显色反应,生成4∶1的红色配合物.配合物的最大吸收峰位于530nm,表观摩尔吸光系数为1.25×105L·mol-1·cm-1,Zn2 浓度在0-480μg/L范围内遵守比耳定律.测定废水中微量锌,结果令人满意.     

2-羟基-4-磺酰氨基苯重氮氨基偶氮苯的合成及与锌的显色反应

在 Triton X- 10 0表面活性剂存在下 ,p H=9.5— 11.5的 Na2 B4O7- Na OH缓冲溶液中 ,2 -羟基 - 4-磺酰氨基苯重氮氨基偶氮苯 (HSDAA)与锌 ( )生成 2∶ 1型深红色配合物。最大吸收峰为 λ=5 30 nm处 ,表观摩尔吸光系数为 1.2 4× 10 5L· mol-1· cm-1。 Zn2 的浓度在 0— 4 80μg/L范围内符合比耳定律。用于测定样品中的微量锌 ,结果满意。     

5-Br-PADAP分光光度法测定手掌面镀锌工具遗留印迹的锌含量

研究2-(5-溴-2吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)分光光度法测定手掌面镀锌工具遗留印迹的锌含量。考察了缓冲液用量、pH、显色剂用量等反应条件对测定的影响;在优化好的条件下,建立了标准曲线并测定了不同接触时间、时间间隔条件下手掌面镀锌工具遗留印迹的锌含量。研究结果表明,pH 8.0的硼砂-硼酸缓冲液4 mL,1 g·L-1的5-Br-PADAP溶液0.2 mL以及10%曲拉通-X-100溶液1 mL为最佳测定条件,在此条件下,Zn2+在0~14 μg范围内呈良好的线性关系,回归方程为y=1.851 34x+0.002 29;在接触时间10 s~5 min内,手掌面镀锌工具遗留印迹锌含量呈上升趋势,在5~10 min内趋于平缓,在接触时间5 min时已基本达到饱和状态,锌含量在0.425~2.377 μg·cm-2;手掌面镀锌工具遗留印迹锌含量在间隔时间0~2 h急剧下降,在2~7 h内下降的幅度逐渐变小,当间隔时间达到7 h时,锌含量仅为0.188 μg·cm-2,与间隔0 h锌含量相比减少了约90%。因此,微量金属显现实验一定要尽早进行。此外,不同间隔时间条件下手掌面锌含量的变化规律与喷洒显现实验中遗留印迹强度变化并非完全对应,这说明手掌面上的锌含量并非唯一可以影响不同间隔时间条件下遗留印迹强度的因素。首次在实验中证实了Zn2+与蛋白质结合后可以被络合能力更强的5-Br-PADAP分子夺取出来而显色的假设。运用此种宏观微观相结合的方法进行研究,有利于对微量金属显现实验中各影响因素机理的探讨,为进一步的研究奠定了基础。     

β-环糊精存在下分光光度法测定微量锌

基于β-环糊精(β-CD)存在下,Zn(l)与2,4-二氯苯基荧光酮(DCIPF)的显色反应,建立了分光光度法测定微量锌的新方法.通过Zn(Ⅱ)-DCIPF-β-CD多元体系,来测量锌含量,体系最大吸收波长550nm,表观摩尔吸光系数ε=1.50×105L·mol-1·cm-1,Zn(Ⅱ)含量在0.23-10.0μg/25mL范围内服从朗伯比尔定律,线性回归方程为A=0.211C(μg/25mL)+0.0122,r=0.9995,干扰离子较少,此法已用于自来水中锌含量的测定,结果令人满意.     

ICP-AES测定玩具中17种元素的特定迁移量

建立了电感耦合等离子体-原子发射光谱法(ICP-AES),可同时测定玩具中17种元素(铝、锑、砷、钡、硼、镉、铬、钻、铜、铅、锰、汞、镍、硒、锶、锡和锌)迁移量.砷、镉、铬、钴、铅、镍和硒的线性范围在0.01-10.0mg·L-1,铝、钡、铜、锰、锶、锌、锑、锡和硼的线性范围在0.1-20.0mg·L-1,汞的线性范围在o.01-1.0mg·L-1,仪器检出限(3s)在o.0003-0.03mg·L-1之间.方法用于玩具中17种元素特定迁移量分析,方法定量限在o.2-5mg·kg-1之间,回收率在88.4％-114.0％之间.重复性测定相对标准偏差(n=6)在0.08％-3.97％之间.方法快速,简单,可靠性高,可多元素同时测定,适用于欧盟玩具安全新指令检测要求.     

1-（4-硝基苯）-3-（2-吡嗪）-三氮烯的合成及与锌（Ⅱ）的显色反应

报道了1-（4-硝基苯）-3-（2-吡嗪）-三氮烯（NPPT）的合成及与锌（Ⅱ）的显色反应。在非离子表面活性剂TritonX-100存在下,于pH8.8的KCl,H3BO3-NaOH缓冲介质中,NPPT与锌（Ⅱ）形成4∶1的黄棕色络合物,在465nm处有一最大吸收,表观摩尔吸光系数为3.15×104L·mol-1.cm-1,10mL溶液中,锌（Ⅱ）量在0—0.56μg范围内符合比尔定律。方法用于葡萄糖酸锌口服溶液中微量锌的测定,测定结果与AAS法相符。     

石墨炉原子吸收法测定水样中的痕量锌

文章对锌含量在μg·mL~(-1)～mg·L~(-1)范围的水样品的石墨炉原子吸收法测定进行了研究。通常由于在石墨炉原子吸收法测定中,由于锌的灵敏度很高使制样过程易受到污染,而火焰原子吸收法测定需较繁杂的富集。通过在样品加入乙醇降低空白值和改进精密度,调节仪器条件的内气流为0.5L·min~(-1)以降低锌的灵敏度,使方法线性范围达到0～20μg·L~(-1)。本法相对标准偏差为0.5％～5.9％之间,检测限为0.098μg·L~(-1)。应用于天然河水、自来水及瓶装矿泉水中锌的测定,结果令人满意。     

富锌培养对转金属硫蛋白侧耳菌丝生长和锌有机化程度的影响

金属硫蛋白(MT) 是一种低分子量、高巯基含量、能结合金属离子的功能性蛋白,将MT基因转入蘑菇,可以获得具有重要生理功能的蘑菇以便为保健食品生产提供原料,但对MT蘑菇的富锌能力缺乏系统研究。文章报道了用电感耦合等离子体-原子发射光谱(ICP-AES)法对富锌培养中的MT侧耳(Pleurotus ostreatus)菌丝和未转化的侧耳菌丝(对照)锌含量进行了测定,分析了MT侧耳菌丝的耐锌能力、富锌特性和锌有机化程度。结果发现转MT侧耳在锌浓度0～1.2 mmol·L-1范围内菌丝生长速度最高,超过1.6 mmol·L-1时菌丝生长开始受到抑制;转MT侧耳有较强的富锌能力,当培养液中锌质量浓度为0.6～1.2 mmol·L-1时,菌丝体中锌含量在2.56～27.49 mg·kg-1之间,与锌添加量呈正相关,且此浓度范围内菌丝体的生长情况良好;在锌浓度为0.6 mmol·L-1的液体培养基中,第7 d转MT侧耳菌丝锌有机化程度为88.7%,比对照(82.1%)显著提高(α=0.05),说明转入侧耳的MT有利于无机锌向有机锌转化;对在不同浓度下培养7 d的两种菌丝测定发现,其有机化程度差异不显著,说明锌与菌体内的物质已经紧密结合形成有机锌复合物,锌浓度对锌的吸收量有影响但对锌的有机化程度影响不大。     

Nuclear interactions of 200 GeV protons in emulsion

Proton-nucleus interactions have been studied in nuclear emulsion exposed to the NAL 200 GeV proton beam. The inelastic mean free path is found to be 35.5 ± 0.8 cm and the average shower particle multiplicity is 12.9 ± 0.2. The angular distribution reveals some characteristics features of proton-nucleus interactions.     

Intensities and strong interaction attenuation of kaonic X-rays

Relative intensities of numerous kaonic X-ray transitions have been measured for the elements C,P,S, and C1, from which level widths due to the strong K-nucleus absorption have been determined. From these and earlier published data, optical potential parameters have been derived and possible consequences on the nuclear matter distribution are discussed.     

Finite-energy corrections and multiplicity fluctuations according to the Gottfried model of hadron-nucleus interactions

Finite-energy corrections and multiplicity fluctuations are considered in the Gottfried model for hadron-nucleus high-energy interactions. The results are that there are appreciable corrections at Serpukhov-NAL energies, such that the Gottfried parameter is ν = 0.25–0.27 instead of, e.g., ν = 0.38, in better agreement with presently available experimental results for proton-nucleus collisions. Further, the sensitivity of the model to some of the input parameters results in appreciable fluctuations in multiplicity, the multiplicity distribution of the part stemming from repeated collisions inside the nucleus being at least as broad as a Poisson distribution.     

A study of the reactions π−p → K1X, K1Σ and K1Y11(1385) at 3.93 GeV/c

We have investigated the final states K¹⁰(890)Σ, $\text{K}{}^{10}\text{(890)Σ}{}^0$ and K¹⁰(890) Y₁¹⁰(1385) produced in π^?p interactions at 3.93 GeV/c. We present the differential cross sections and spin density matrix elements for the resonances as functions of momentum transfer, as well as the gL and Σ⁰ polarizations. The Σ⁰ polarization is found to be positive and maximal. An amplitude analysis is performed for the K¹ Λ and $\text{K}{}^1\text{Σ}{}^0$ reactions, and it is found that one natural parity transversity amplitude is dominant for the latter.     

Experimental tests of the factorisation of Regge trajectories in the proton fragmentation region

We present double differential cross sections for the reactions K^? + p → π^± + anything at 8.25 GeV/c. Using published data for reactions K⁺ + p→ π^? + anything and p + p → π⁺ anything we predict the differential cross sections for γ + p → π^? + anything, π^? + p → π^? + anything and π^? + p → π⁺ + anything in the target fragmentation region based on factorisation of the pomeron and Regge trajectories. Our predictions agree with the experimental data and support the hypothesis of factorisation of the Regge trajectories in the target fragmentation region.     

Path integrals and the indefiniteness of the gravitational action

The Euclidean action for gravity is not positive definite unlike those of scalar and Yang-Mills fields. Indefiniteness arises because conformal transformations can make the action arbitrarily negative. In order to make the path integral converge one has to take the contour of integration for the conformal factor to be parallel to the imaginary axis. The path integral will then converge at least in the one-loop approximation if a certain positive action conjecture holds. We perform a zeta function regularization of the one-loop term for gravity and obtain a non-trivial scaling behaviour in cases in which the background metric has non-zero curvature tensor, and hence non-trivial topologies.     

A study of the reactions KN→Σ(1385)π between 0.6 and 1.2 GeV/c

An energy-dependent partial-wave analysis of the reaction $\text{K}\text{N}\text{→Σ(1385)π}$ has been performed in the energy region lying between 1.65 and 1.85 GeV. The resonant amplitudes of seven well known Y¹ resonances have been determined, and used to compute the corresponding (8) ? (10) SU (3) coupling constants.     

空芯光纤中介质层材料色散的研究

提出一种根据实验测量的损耗谱曲线,通过曲线拟合等方法获得空芯光纤巾介质层薄膜材料色散性质的方法,并使用此方法得到了数种空芯光纤中常用的介质层材料在可见光与近红外Ⅸ域的色散柯西公式.将得列的介质层材料色散引入到空芯光纤传输损耗谱的理论计算中之后,相对于小考虑材料色散或者使用文献中提供的色散数据进行计算的结果,理论计算结果能更好地符合实验测量结果,从而能够在理论上更加准确地预估空芯光纤在可见光与近红外区域的低损耗窗口的位置.所获得的材料色散柯西公式对于空芯光纤的高性能化没计有重要的辅助作用.     

On the slope of the scalar Kℓ3 decay form factor

We discuss a mechanism, based on exact threshold theorems in the limit of SU(2) × SU(2) symmetry, which can be used to estimate a certain suppression of the scalar K_?3 decay form factor at low momentum transfers, while maintaining the validity of the Callan-Treiman relation.     

On the thermodynamical stability of black holes in nonlinear electrodynamics

We analyze the thermodynamical stability of static and spherically symmetric black hole solutions with nonlinear electromagnetism as a source, and show that any sequence of such black holes in isolation that includes the Schwarzschild black hole is stable in the (β_M,M)$({\beta }_M,M)$ plane for any nonlinear Lagrangian describing the electromagnetic field. The study of three exact solutions (which include the Schwarzschild solution in some limit) in the (β_Q,Q)$({\beta }_Q,Q)$ plane show that they are stable in the microcanonical ensemble, and unstable or less unstable (due to the existence of a turning point) in the canonical ensemble. If the less unstable configurations are stable, our results indicate that they would be in equilibrium with a reservoir at a higher temperature than the corresponding Reissner–Nordstrom configuration. An expression for the heat capacity at constant charge valid for any Lagrangian describing nonlinear electromagnetism is also presented. It displays a divergence with a change of sign that occurs precisely at the turning point obtained by the Poincarè method.