轻稀土元素在大鼠组织器官中的分布特征

研究La,Ce,Pr,Nd,Sm,Eu,Gd在大鼠组织器官中的分布规律。以雄性SD大鼠为试验对象,适应性喂养一周后剃去大鼠被毛,随机分为对照组和柠檬酸稀土低、中、高剂量组,每组10只共4组,剂量分别为0,50,500,5000 mg.kg-1(体重)。灌胃4周后,采集大鼠被毛、肝脏、脾脏等脏器。用等离子体质谱(ICP-MS)法测定大鼠被毛、肝脏、脾脏、全血中La,Ce,Pr,Nd,Sm,Eu,Gd轻稀土元素含量。轻稀土元素在大鼠全血、毛发及脏器中的分布特征分别为:肝、脾脏中的分布与摄入量完全对应;全血中分布趋于自然分布特征;股骨中对照及低剂量组的分布与摄入量倒置;而毛发中则呈现与受试物一致的特征,在一定程度上反映机体的稀土环境暴露水平。     

乳腺肿瘤患者血清稀土元素的检测与分析

比较乳腺肿瘤和对照人群血清稀土元素含量差异,探究恶性肿瘤患者不同分化类型与血清稀土元素含量的相关性,为乳腺肿瘤的治疗及预后提供科学依据;采用病例对照研究,纳入90例乳腺肿瘤患者(良恶性肿瘤患者各45例)和95例对照,恶性肿瘤患者进一步细化为高分化组28例和低分化组15例;利用电感耦合等离子体质谱仪(ICP-MS)测定两组人群血清中15种稀土元素的含量;结果显示La, Ce, Pr, Nd, Sm, Y, Eu, Gd, Tb, Dy, Ho, Er, Tm 13种稀土元素浓度在病例组和对照组间的差异有统计学意义(P0.05),其中La, Ce, Pr, Nd, Sm, Y含量在仪器定量限以上,且病例组中浓度均低于对照组浓度; Logistic回归显示La, Ce, Y调整人口学特征后OR值有统计学意义(P0.05);血清La, Ce, Pr, Nd, Sm, Y浓度在对照组、良性肿瘤组、恶性肿瘤高低分化组间差异有统计学意义(P0.05);相关分析显示Ce, Pr, Nd, Sm, Y与乳腺恶性肿瘤组织学评分存在一定的关联(P0.05),且均为负相关。结论:良性、恶性乳腺肿瘤均会导致病人血清稀土元素含量下降,元素La, Ce, Y可能是乳腺肿瘤患者的保护因素,乳腺恶性肿瘤恶化程度与体内稀土元素代谢紊乱存在一定关联。     

赤泥中稀土元素的主成分分析和聚类分析

采用电感耦合等离子体原子发射光谱法(ICP-AES)测定了不同来源的赤泥样品中包含La,Ce,Pr,Nd,Sc和Y在内的6种稀土元素的含量,建立了赤泥中稀土元素的指纹谱,并用SPSS 20.0对稀土元素进行了主成分分析和聚类分析。结果表明:主成分分析选出2个主因子,La,Ce,Pr,Nd,Sc和Y均是赤泥的特征元素;聚类分析将稀土元素和赤泥样品均聚为两类,这与稀土元素的含量、性质以及铝土矿的品质、地域分布有一定的联系。     

湖州表层土壤稀土元素含量及分布特征

为了研究湖州表层土壤样品中稀土元素的分布特征,利用ICP-MS测定了土壤中稀土元素的含量。结果表明湖州表层土壤中稀土元素含量的大小顺序为：Ce＞La＞Nd＞Pr＞Sm＞Gd＞Dy＞Yb＞Er＞Eu＞Ho＞Tb＞Tm＞Lu,遵循Oddo-Harkins法则。湖州表层土壤中稀土元素的分量均值和总量均值皆高于全国水平,稀土元素存在显著的分馏现象,轻稀土元素明显富集。表层土壤中Ce和Eu都有部分亏损。     

用单-2-乙基己基磷酸体系薄层层析法分离稀土元素的研究

在硅胶H/硝酸铵/CMC/H_2O(W/W33:1:1:100)的薄层板上以单-2-乙基己基磷酸/甲基异丁基酮/异丙醚/硝酸(V/V1:12:8:20)为展开剂时,各稀土元素间能同时表现出一定的△R:值。分离La、Ce、Pr、Nd、Sm、Gd、Dy、Er、Y、Yb的混合液,定性结果令人满意。经对寻乌、定南混合稀土矿分离、测试,确定了寻乌矿中含有稀土元素是La、Pr、Nd、Sm、Gd、Dy、Y;定南矿中含有稀土元素是La、Ce、Pr、Nd、Sm、Gd、Dy、Er、Y、Yb。     

硅铝合金中稀土及非稀土元素的ICP—AES法测定

由于稀土元素的化学性质极为相近,通常采用高分辨率的发射光谱法分析。近年来ICP-AES在稀土分析中得到广泛应用。本文在前人工作的基础上,采用ICP-AES测定了硅-铝合金中稀土元素La、Ce、Pr、Nd、Y以及非稀土元素Si、Mn、Mg、Cu、Zn、Fe、Ti等的含量。     

陕南茶叶稀土元素产地特征研究

为了掌握陕南茶叶中稀土元素含量和分布状况,并利用稀土元素对茶叶产地进行判别,采用ICP-MS法对陕南地区44个茶叶样品中16种稀土元素进行了测定。结果表明:茶叶中不同稀土元素含量差异较大,其中La,Ce,Nd含量较高,平均含量分别为124.81,172.13,87.20μg·kg-1;茶叶样品中稀土氧化物含量范围为200.32~1558.35μg·kg-1,总体上呈东高西低趋势,且均低于国家规定限量;茶叶中稀土元素随地域变化表现出不同分布特征,但具有相似的丰度模式;利用主成分分析将茶叶稀土元素归结为轻稀土组和重稀土组,间接地证明轻稀土元素和重稀土元素在从土壤到茶叶迁移过程中仍存在着差异;聚类分析结果表明,稀土元素可作为陕南茶叶产地判别的重要指标。     

电感耦合等离子体质谱（ICP-MS）法测定黄精中15种稀土元素及其指纹图谱绘制

为了准确测定黄精中稀土元素的含量,采用电感耦合等离子体质谱（ICP-MS）法同时测定黄精中15种稀土元素（La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu）的含量,进而绘制稀土元素指纹图谱,以稀土元素含量的平均值构建黄精稀土元素标准指纹图谱,作为鉴定黄精中药材的参考依据。黄精样品采用微波消解法处理后,通过在线引入内标溶液,采用ICP-MS法测定15种稀土元素的含量,采用OriginPro 2021绘制稀土元素指纹图谱和进行主成分分析,采用SPSS 26.0进行聚类分析。15种稀土元素的线性关系、重复性、精密度良好,平均加标回收率在97.0%~103.3%,相对标准偏差小于等于1.74%。黄精中Ce、La、Nd含量相对较高,Ce含量为53.02～2004.58 μg/kg,位居第一。聚类分析和主成分分析结果表明,样品聚为2类,同一产地的样品能够较好地聚在一起。黄精药材中15种稀土元素的指纹图谱具有相似的分布形态,具有较强的特征性和一致性,相似度均大于0.950。该方法操作简单,准确可靠,能满足实验分析要求,可为黄精的质量控制和药理研究提供参考;建立的指纹图谱可用于黄精的鉴别。     

薄层色谱分离测定十五种稀土元素

本文论述了用薄层扫描分离测定稀土元素的新方法。当流动相为二-(2-乙基已基)磷酸酯(HEDHP)/单-(2-乙基己基)-2-乙基己基磷酸酯(HM(EH)EHP)/磷酸三丁酯(TBP)/四氢呋喃(THF)/硝酸(HNO_3)/异丙醚(i-Pr_2O)(111 52 5 521 86 10000 V/V)时,第一组元素(La,Ce,Pr,Nd,Sm)能完全分离;第二组元素(Eu,Gd,Tb,Dy,Y,Ho,Er,Tm,Yb,Lu)的Rf值均大于第一组元素,且不干扰测定。当流动相为HDEHP/HM(EH)EHP/TBP/THF/HNO_3/i-Pr_2O(68 43 27 460 103 10000 V/V),第二组元素能完全分离,此时第一组元素停留在起始线上,二组互不干扰。同时对稀土元素进行了定量测定的研究,在0.030～0.600(μg)的范围内,各稀土离子的测定符合比耳定律,测得各稀土元素的检出限La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Y,Ho,Er,Tm,Yb,Lu分别为14,15,18,17,15,14,14,17,18,14,21,23,29,30和31ng。样品中各稀土元素的回收率除样品1中La和Pr偏大一些外,均在95%～108%范围内。各样品中测得的稀土元素含量和光谱法所测得结果基本相符,结果令人满意。     

薄层色谱法分离稀土元素的研究

本文报道了用薄层色谱法分离轻稀土元素的色谱条件。在硅胶-淀粉-硝酸铵的薄层板上,研究了展开剂N263/正辛醇/石油醚/浓HNO_3各组份比例的变化对轻稀土元素R_f值的影响。实验结果表明,各稀土元素的R_f值随它们的原子序数增大而减小;当选择展开剂各组份的最佳体积比为6.0:7.0:25.0:1.0时,La、Ce、Pr、Nd、Sm、Eu和Gd七个稀土元素可获得完全分离,用三溴偶氮胂作显色剂,稀土元素的检测极限可达0.01μg。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。