电感耦合等离子体原子发射光谱法测定铀锆合金中钙锂镁钠

铀锆合金燃料中的杂质元素会影响其运行的安全性,准确测定Ca、Li、Mg、Na元素的含量具有重要意义。先使用硝酸-氢氟酸溶解样品,再采用UTEVA萃淋树脂,在酸性介质中使铀基体与待测元素定量分离,选择Ca 422.673nm、Li 670.784nm、Mg 279.553nm、Na 589.592nm作为分析谱线,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定铀锆合金中Ca、Li、Mg、Na的分析方法。使用1mol/L硝酸淋洗UTEVA萃淋色谱柱,这一分离流程对铀的去污因子约为4.0×10⁴。Ca、Li、Mg、Na的出峰体积在6~10mL,因此保留10mL淋洗液可以满足Ca、Li、Mg、Na的测定要求。Ca、Li、Mg、Na的质量浓度为0.025~0.50mg/L时与其发射强度呈线性关系,线性相关系数均不小于0.9990;方法检出限为0.1~1.0mg/kg。按照实验方法测定铀锆合金中Ca、Li、Mg、Na,测定结果的相对标准偏差(RSD,n=6)小于3%;回收率为90%~105%。     

CL—TBP萃淋树脂分离—分光光度法连续测定微量铀和钍

研究了在铀水冶工艺中,以CL-TBP萃淋树脂分离-连续分光光度法测定微量铀和钍的方法及其应用.在低温下,用混合铵盐熔矿,然后用1 mo1/L硝酸溶解,在1 mo1/L HNO3-1.25 mol/L NH4NO3体系中,以CL-TBP萃淋树脂选择性吸附铀和钍.对吸附在树脂上的铀、钍,先用4 mo1/L盐酸淋洗钍,再用水淋洗铀,之后以偶氯胂M作显色剂,对淋洗液中的钍和铀进行连续分光光度测定.在pH＝2.0的一氯乙酸-醋酸铵缓冲介质中,铀与偶氮胂M形成紫红色配合物,该配合物在波长645 nm处有最大吸收,表观摩尔吸光系效E645nm＝4.8 ×104L·mol-1·cm-1.在4 mo1/L盐酸溶液中,钍与偶氮胂M形成紫红色配合物,此配合物在波长665 nm处有最大吸收,表观摩尔吸光系数ε666nm=9.67×104L·mol-1·     

铀钼共存体系中低浓度铀和钼的测定

研究了铀钼共存体系中低含量铀和钼的测定方法。体系中铀含量高而钼含量低时，可采用CL-TBP萃淋树脂先分离铀。然后以硫氰酸盐光度法测定钼；体系中钼含量高而铀含量低时，可在1mol／L HNO3介质中沉淀分离铀，再用萃淋树脂富集铀，用水淋洗后，再以溴代光度法测定铀。结果表明，铀、钼回收率均在95％～105％之间，方法的相对标准偏差小于5％。     

高钍体系中微量铀的ICP-MS法测定

建立了准确测定高钍体系中微量铀的方法。用CL-TBP萃淋树脂分离铀、钍,用5 moL/L盐酸溶液淋洗钍,12 mL水(相对1 g树脂)淋洗铀,淋洗剂流速1.0 mL/min,淋洗液定容至25 mL;用~(187)Re作内标元素,以ICP-MS法测定铀。结果表明:方法加标回收率在96.4%～108%之间,相对标准偏差为2.73%(n=6),测定铀的检出限为6.0 ng/L;方法准确可靠,满足工艺要求。     

电感耦合等离子体原子发射光谱法测定煤与焦炭中18种元素

采用电感耦合等离子体原子发射光谱(ICP-AES)法直接测定煤与焦炭中Si,P,Al,V,Cr,Cd,Pb,Cu,Co,Ni,Zn,K,Na,Fe,Ca,Mg,Mn,Ti 18种元素。样品被灰化后取一定量灰样,用氢氧化钠熔融,热水和盐酸浸取,溶液用于测定Si和P,得到煤或焦炭灰中Si,P含量。另取灰化后的全部灰样,用高氯酸和氢氟酸溶解并加热至赶尽高氯酸,用稀硝酸溶解,溶液用于测定Al,V,Cr,Cd,Pb,Cu,Co,Ni,Zn,K,Na,Fe,Ca,Mg,Mn和Ti,得到煤或焦炭中16个元素含量。Si和     

多向观测电感耦合等离子体原子发射光谱法同时测定碳酸盐中11种组分

采用盐酸、硝酸、高氯酸和氢氟酸溶解试样,在0.63 mol/L的硝酸介质中,选择信背比大,干扰少的光谱线作分析线,通过径向衰减观测方式测定Al,Fe,Ca,Mg,K,Na,P,Ti元素,轴向方式测定Si,Mn,S元素,实现了电感耦合等离子体原子发射光谱法测定碳酸盐中SiO2,Al2O3,Fe2O3,CaO,MgO,K2O,Na2O,P2O5,TiO2,MnO,SO311种组分。主量元素Ca对其他元素的测定有抑制作用,采用基体匹配方法可消除,其他元素间的相互干扰很小,对测定没有影响。用本法测定了石灰岩和白云     

火焰原子吸收光谱法测定l_2 一Kl浸出液中的微量金

本文采用SnCl_2将I_2还原成I~-,在5%的王水体系中用TBP萃淋树脂富集分离金,用 10%HCl溶液洗去杂质元素,以 0.lmol/L HCl—0.2mol硫脓混合溶液解脱金,火焰原子吸收法测定.方法精密度优于土 5%,回收率为 96～108%,方法检测下限为0.lmg·Au/L.     

标准曲线法测定高纯工艺试剂盐酸中痕量金属杂质

试验研究建立了高纯工艺中重要试剂盐酸中痕量杂质的分析方法。试样经过蒸发浓缩,挥发除去水和挥发性试剂,保持亚沸状态蒸干。残渣用硝酸溶解,用ICP-MS进行测定,可同时测定Na、Mg、Al、K、Ca、Fe、Ni、Cu、Zn、Cd、Ag、Sb、Pb、Bi等杂质元素。     

电感耦合等离子体原子发射光谱法测定微孔碳分子筛及其洗脱液中的金属元素含量

通过电感耦合等离子体原子发射光谱法(ICP-AES)与试样不同预处理方法相结合分别测定了微孔碳分子筛(CMS)及其洗脱剂(HCl+HF+H2O2)中的Fe,Al,Na,Zn,Ca,Mg,K,Cu8种元素。考察了样品预处理方法对测定结果的影响。结果表明:采用灰化法处理样品除Zn测定结果偏低外,其它元素的测定结果都较酸洗脱法高;在酸洗脱法中,以HCl+HF+H2O2为洗脱剂较用HCl,HNO3,HCl+HF,HCl+HNO3的洗脱效果好。试验选择用灰化法处理样品以测定微孔碳分子筛总体的金属元素含量;用HCl+HF+H2O2为洗脱剂以测定从微孔碳分子筛中洗脱下来的金属元素含量。用该法测定碳分子筛试样总体和洗脱的Fe,Na,Zn,Ca,Mg,K,Cu,平均加标回收率分别为91%～120%和97%～110%,相对标准偏差分别为0.8%～5.6%和1.5%～4.3%。实验还表明,通过用不同的溶液选择性洗脱表面的金属,并与ICP-AES测定相结合有望成为分析多孔碳材料表面的金属元素分布和形态的一种方法。     

Cl-P_(350)萃淋树脂及其对钪的萃取

本文介绍了合成Cl-P_(350)萃淋树脂的一种方法。测定了Cl-P_(350)萃淋树脂对钪的萃取饱和容量,考察了树脂中萃取剂在水相中的溶解损失及树脂的吸附稳定性与再生性能。重点讨论了盐酸体系Cl-P_(350)萃淋树脂对Sc与Ti(Ⅳ)、Ca、Fe(Ⅲ)及RExOy的分离,探讨了用Cl-P_(350)萃淋树脂提取钪的可能性,结果令人满意。此外,还对Cl-P_(350)萃淋树脂的形貌和表面结构做了扫描电镜观察。     

Mapping brain networks engaged by, and changed by, learning

Major goals of research into the neurobiology of learning and memory are to identify (1) brain areas/circuitries that subserve different mnemonic functions and (2) chemistries that encode the memory trace. The discovery that activity modulates neuronal gene expression provided techniques attendant to the first goal and candidates for cellular changes pertinent to the second. Studies in our laboratories have exploited activity-regulated changes in c-fos gene expression to map regions engaged in two-odor discrimination learning, with particular interest in neuronal groups in hippocampus and amygdala. The results of these studies demonstrate that the subdivisions of hippocampus and amygdala do not act in concert across behaviors but are differentially activated depending on task demands. In hippocampus, preferential activation of field CA3 was uniquely associated with initial learning of an odor pair, whereas predominant activation of CA1 occurred with exploration of a novel field and with overtrained responding to odors. The reappearance of precisely the same balance of subfield activation within disparate behavioral contexts was taken to suggest that the hippocampus has basic modes of function that recur in different circumstances and make rather generalized contributions to behavior. Within the amygdala, the basolateral division was most prominently active during task acquisition but not during performance of the well-learned discrimination. Indeed, the amygdala appeared to play the dominant role relative to hippocampus in the early stages of associating positive and negative valences with discriminative cues. These results demonstrate that the balance of neuronal activity both within and between limbic structures changes across sequential stages of odor learning in a fashion that is likely to define behavioral output.     

Career by choice, not by chance

OBJECTIVE: To analyze the effects of a prospective peer review program on diagnostic accuracy in a routine cytopathology laboratory. STUDY DESIGN: For the study, 4,836 consecutive cases subjected to fine needle aspiration cytology (FNAC) over a one-year period were used. Nine pathologists performed both reporting and peer review functions. Disagreements were classified into "diagnostic errors" and "diagnostic discrepancies," depending on their impact on patient care. The effect of this review on turnaround time was statistically analyzed. A retrospective review of 4,025 cases from the preceding year was performed for comparison. RESULTS: Sixty-six cases with diagnostic disagreements were detected by prospective review. There were 28 diagnostic errors and 38 diagnostic discrepancies. The initial turnaround time for diagnostic FNAC in 90% of total cases was < 24 hours; mean delay for the remainder was 3.3 days. Prospective peer review added a further delay of 1 and 1.5 days, respectively. The number of diagnostic disagreements was significantly higher in the retrospective review (P < .01). CONCLUSION: Prospective peer review of diagnostic FNAC resulted in improved accuracy of diagnosis and reduced potential for inappropriate therapy; however, turnaround time was significantly increased.     

多波长分光光度法同时测定Fe、Cu、Cr、Ni

研究多波长分光光度法对Fe、Cu、Cr、Ni 4 种金属同时定量分析.考察了通常存在的Ca、Mg、Zn对测定的干扰,确定了4 种金属的最佳吸收波长,并在特定波长下测定摩尔吸光系数,建立了完整的线性方程.采用本方法对配制的Fe、Cu、Cr、Ni 混合溶液进行测定,验证其线性方程的准确性,结果表明其相对误差在±5 %以内.考虑不同样品金属离子的含量不同,对多波长分光光度法进行了测定下限的研究.结果表明:采用本方法Fe、Cu、Cr、Ni 的测定下限分别为5×10-4 mg/mL、1×10-3 mg/mL、5×10-3 mg/mL、5×10-3 mg/mL, 在此浓度以上的样品均可获得可靠的定量分析结果. 最后对实际电镀污泥中Fe、Cu、Cr、Ni 的含量进行测定,分析测定结果与原子吸收分光光度法是一致的.      

Psychologist by training, bureaucrat by practice.

Communication with Congress; state and local officials; and numerous professional, advocacy, scientific, and public interest groups is essential to working on mental health and substance abuse issues at the federal policy level. The public administrator's work is diverse and fast-paced, involving issue analysis, proposal development and justification, public speaking, and dialogue with advocacy and policy analysis groups. Making decisions that will serve the public good in the long run is the core of the job. As the competition for resources escalates, the perspectives' of consumers of services and their families are important to guide decisions. In a career that is based on interactions, relationships, judgments, and evaluation of multifaceted issues, success is measured by a reputation for fairness and by accomplishments that are based on numerous individual decisions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ICP—AES法测定海绵铁中砷、锡、铅、锑、铋

文章提出了用ICP—AES法直接测定海绵铁As、Sn、Pb、Sb、Bi含量的方法,建立了最佳工作条件。对各元素的分析线进行了选定,考察了干扰情况、介质酸度等对测定结果的影响。方法准确,快速简便,重现性好。     

原子荧光光谱法测定土壤中的铅、铬、镉、汞、砷、锌、铜、镍等元素研究

土壤无机污染物铅、铬、镉、汞、砷、锌、铜、镍这八大重金属,是一般土壤检测中的必检项目。金属元素在土壤中积累富集后,有可能通过雨水迁移,造成地下水,地表水污染,或者通过农作物进入食物链,进而影响食品安全和人体健康,因此,对这些元素的检测显得尤为重要。本文采用原子荧光光谱法对土壤中的金属元素进行测量,同时结合微波消解技术对样品进行处理,确保测量数据的准确性。     

Enhancement by the tricyclic antidepressant, desipramine, of experimental carcinogenesis in rat colon induced by azoxymethane

The effects of the tricyclic antidepressant drug desipramine on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), and on the serum norepinephrine (NE) concentration and the labeling index of colon mucosa were investigated in Wistar rats. Rats were treated s.c. with 7.4 mg AOM/kg body wt once a week for 10 weeks, and also s.c. with 10 mg desipramine hydrochloride (desipramine)/kg body weight until the end of the experiment. Treatment with desipramine significantly increased the incidence, but not the number, of colon tumors in week 35. However, it did not influence the location and the histological appearance of the colon tumors or the histological types of colon adenocarcinomas. Furthermore, it significantly increased the serum NE level and the labeling index of colon mucosa during and after AOM treatment. These findings indicate that desipramine enhanced the development of colon tumors and that its effect may be related to its effect in increasing proliferation of colon epithelial cells.     

Metabolism of monoterpene alcohol, linalool, by a soil pseudomonad

A microorganism of the genus Pseudomonas has been isolated from the soil by enrichment culture techniques with linalool(I) as the sole source of carbon and energy. The organism is also capable of utilizing limonene, citronellol, and geraniol as substrates but fails to grow on citral, critranellal, and 1,8-cineole. Fermentation of linalool by this bacterium in a mineral salt medium results in the formation of 10-hydroxylinalool(II), oleuropeic acid (IX), 2-vinyl-2-methyl-5-hydroxyisopropyl-tetraphydrofuran)linalool oxide, V), 2-vinyl-2-methyl-tetrahydrofuran-5-one(unsaturated lactone, VI), and few unidentified minor metabolities. Probable pathways for the biodegradation of linalool are presented.     

ICP—OES法测定铝铁中的铝锰硅磷铜铁含量

用稀王水溶解试样,ICP—OES法直接测定铝铁中的铝、锰、硅、磷、铜、铁的含量。对样品溶解酸度、元素谱线选择、背景校正扣除、样品基体及待测元素间干扰等因素进行了试验研究。采用基体匹配与背景扣除法消除基体对待测元素的光谱干扰,确定了最佳实验条件。结果表明：各元素的加标回收率为96．0％～105．0％,相对标准偏差小于2．50％。本法与化学分析方法对照,测定结果一致,已用于铝铁产品的检验。     

电感耦合等离子体原子发射光谱法测定镍基合金中钨、钼、钴、铝、钛、铌、铁元素

针对镍基合金的溶解方法、元素分析谱线的选择、仪器分析参数的优化、内标溶液的选用、基体元素的影响、干扰元素的校正及消除方法等进行了研究,确定了最佳试验条件;试验结果表明:检出限为0.024mg/L～0.85mg/L;加标回收率为97.1%～105.7%;方法的精密度(RSD,n=11)小于1.0%,本试验测定结果与标钢认定值和湿法分析结果做对照,都在允许偏差范围内,表明此方法精密度好,准确度高。