U(Ⅵ)在人体组织液中的形态模拟

铀的毒性与其体内形态密切相关,研究铀在人体组织液的形态有助于了解铀的人体毒理。本工作采用热力学平衡模拟方法研究U(Ⅵ)在人体组织液中的形态。建立了含多种金属离子和小分子配体组成的多相组织液热力学平衡模型,模拟研究了H₂OCO₃^2--PO₄^3-体系中UO₂²⁺的形态分布、组织液中UO₂²⁺的形态分布及总CO₃^2-次氮三酯酸（NTA）浓度对组织液中UO₂²⁺形态分布的影响。结果表明,在H₂O-CO₃^2--PO₄^3-体系中,当UO₂²⁺总浓度为1.5 μmol/L、pH>7.0时,UO₂²⁺主要以 [UO₂(CO₃)₃]^4-和[UO₂(CO₃)₂]^2-存在,pH<6.0时,主要以UO₂HPO₄和UO₂(H₂PO₄)₂存在;当UO₂²⁺浓度为0.15 mmol/L、pH>7.0时,UO₂²⁺仍以 [UO₂(CO₃)₃]^4-和[UO₂(CO₃)₂]^2-为主,pH3～6时,主要以固相(UO₂)₃（PO₄)₂出现。在组织液模型中,当UO₂²⁺总浓度为1.5 μmol/L、pH>7.0时,UO₂²⁺主要以 [UO₂(CO₃)₃]^4-、[UO₂(CO₃)₂]^2-和[UO₂Cit₂]^4-存在,pH<6.0时,主要以[UO₂Cit₂]^4-存在;当UO₂²⁺浓度为0.15 mmol/L、pH>7.0时,UO₂²⁺仍以 [UO₂(CO₃)₃]^4-、[UO₂(CO₃)₂]^2-和[UO₂(CO₃)₃]^4-存在,pH 3～6时,以固相(UO₂)₃（PO₄)₂为主。当UO₂²⁺浓度为1.5 μmol/L或0.15 mmol/L时,提高CO₃^2-浓度能改变UO₂²⁺在组织液中的形态分布：[UO₂(CO₃)₃]^4-含量升高,[UO₂(CO₃)₂]^2-和[UO₂Cit₂]^4-含量降低。NTA的加入改变了组织液中UO₂²⁺的形态分布,但并没产生UO₂²⁺的NTA螯合物形态。当UO₂²⁺浓度为1.5 μmol/L时,提高NTA浓度可使UO₂²⁺主要以[UO₂Cit₂]^4-存在;当UO₂²⁺浓度为0.15 mmol/L时,UO₂²⁺主要以[UO₂(CO₃)₂]^4-形式存在。     

Pu(OH)4(am)与碳酸根的配位行为研究

为了解在惰气环境Pu(OH)_4(am)与碳酸盐溶液中HCO^-₃，CO^2-₃的配位行为，考察了放置时间对Pu总浓度的影响；同时也考察了pH值、碳酸根总浓度变化对碳酸盐溶液中Pu的主要存在形态及溶解总浓度的影响。实验结果表明，HCO^-₃离子与Pu(OH)_4(am)生成[Pu(OH)₄(HCO₃)₂]^2-（lg K=-2.61±0.18, lgβ=54.25±0.18）或[Pu(OH)₂(CO₃)₂]^2-（lgK=-2.61±0.18, lgβ=46.91±0.18）；CO^2-₃离子与Pu(OH)_4(am）生成[Pu(OH)₄(CO₃)₂]^4-（lgK=-3.52±0.11, lgβ=53.33±0.11）。可能的配位反应方程式为： Pu(OH)_4(am)+2HCO^-₃ = [Pu(OH)₄(HCO₃)₂]^2-, Pu(OH)_4(am)+2HCO^-₃ =[Pu(OH)₂(CO₃)₂]^2-+2H₂O, Pu(OH)_4(am)+2CO^2-₃=[Pu(OH)₄(CO₃)₂]^4-。     

氧化硼对铁磷酸盐玻璃陶瓷固化体的影响

研究了不同B₂O₃掺量对铁磷酸盐玻璃陶瓷高放废物固化体结构和性能的影响。应用溶出速率法（DR）对固化体进行了化学稳定性测试,使用傅里叶变换红外光谱（FTIR）和X射线衍射（XRD）方法研究了样品的结构。研究结果表明：玻璃陶瓷固化体的主晶相为独居石;B₂O₃的引入对玻璃陶瓷固化体的化学稳定性影响较大,以10%（摩尔分数）的B₂O₃代替Fe₂O₃制得的固化体化学稳定性最佳,其28d的质量浸出率约为7.81×10^-9g•cm^-2•min^-1;试样中存在大量正磷酸基团［PO₄］^3-和少量焦磷酸基团［P₂O₇］^4-,无偏磷酸基团［PO₃］^-存在,固化体中的B主要以［BO₄］四面体基团形式存在。     

Re/99Tcm(CO)3+黄酮复合物的合成及其与Aβ斑块的结合特性

为研制新型⁹⁹Tc^m(CO)₃⁺标记的黄酮类Aβ显像剂,设计合成了同型Re/⁹⁹Tc^m(CO)₃⁺黄酮类衍生物,用荧光法研究了Re(CO)₃⁺黄酮类衍生物在体外与Aβ斑块的结合特性,并初步观察了其在昆明小鼠体内的生物分布。结果表明,Re(CO)₃⁺黄酮类衍生物的亲和常数(K_d=5.43 nmol/L)比放射性碘标记的黄酮类衍生物高。正常小鼠的动物分布结果表明,2 min内脑初始摄取较高（0.46±0.23 %ID/g）,且清除较快（120 min时为0.13±0.04 %ID/g)。以上结果表明,⁹⁹Tc^m(CO)₃⁺黄酮类衍生物有进一步研究的价值。     

铀随地下水迁移的地球化学屏障物料选择

通过热力学计算得到的铀在场址地下水中的主要存在形态为UO₂(CO₃)^2-₂、UO₂(CO₃)^4-₃、UO₂CO⁰₃、UO₂(HPO₄)^2-₂，它们占99％以上。本工作对4种场址土壤进行表面电荷及K_d值测定。测定结果表明：场址Ⅲ土壤有最大的表面正电荷值，且对铀有极高的吸附比，是铀的良好吸附屏障物料。采用测定K_d的方法研究了8种添加剂对4种场址土壤以及炭质砂岩、Ca(OH)₂对Ⅲ号土壤的改良作用。结果表明：大部分添加剂未对铀产生屏障作用；炭质砂岩、Ca(OH)₂改善了Ⅲ号土壤的吸附性能，且Ca(OH)₂是比炭质砂岩更为优越的添加剂。     

氨基羟基脲与Pu(Ⅳ)的还原动力学研究

研究了氨基羟基脲(HSC)与Pu(Ⅳ)的还原反应动力学,其动力学方程式为：-d_c（Pu(Ⅳ)）/d_t=kc（Pu(Ⅳ））c^1.06（HSC）c^-0.43（H⁺）c^-0.58（NO₃^-）,在22.1℃时反应速率常数k＝(11.8±1.1)（mol/L）^-0.046•s^-1,活化能为(71.0±1.0)kJ/mol。研究了氨基羟基脲浓度、H⁺浓度、硝酸根浓度、Fe³⁺浓度、UO₂²⁺浓度对氨基羟基脲与Pu(Ⅳ)还原反应速率的影响,增加氨基羟基脲浓度,降低H⁺浓度、硝酸根浓度,Pu(Ⅳ)还原速度增加;UO₂²⁺浓度和Fe³⁺浓度对Pu(Ⅳ)还原速度基本无影响。     

UO2(NO3)2-TcO4——HNO3-H2O/TBP-OK体系萃取过程中锝分配比数学模型研究

通过文献报道的锝分配比实验数据与计算结果的分析和对比,引入校正函数P(c⁰(U),t)对现有锝分配比模型进行改进,建立了UO₂(NO₃)₂-TcO₄^--HNO₃-H₂O/TBP-OK萃取体系中锝的数学模型,并编写了锝分配比计算程序。利用国内外相关文献报道的179组实验数据对该程序进行验证,符合情况良好。通过与锝分配比文献数据以及原模型计算结果对比,对改进后锝分配比模型的性能进行了评估,改进结果明显优于原模型。改进后的模型可作为UO₂(NO₃)₂-TcO₄^--HNO₃-H₂O/TBP-OK体系、10～60℃、U浓度0～280g/L、硝酸浓度0.1～5mol/L范围内锝和铀萃取行为计算机模拟的基础。     

99Tcm(CO)3-CNRGD的制备及生物学评价

合成了含异腈基团的多肽偶联物（CNRGD）,并用［⁹⁹Tc^m(CO)₃(H₂O)₃］⁺标记,得到具有与整合素α_vβ₃受体多结合位点的⁹⁹Tc^m(CO)₃-CNRGD,并对其进行了体内外生物学评价。结果表明,在优化的标记条件下,⁹⁹Tc^m(CO)₃-CNRGD的标记率达到77%,纯化后,标记物放射化学纯度大于96%。体外稳定性实验显示其具有很高的稳定性;脂水分配系数显示其具有较好的脂溶性。正常小鼠体内分布显示,⁹⁹Tc^m(CO)₃-CNRGD在血液中清除较快,主要通过肝肾代谢。荷MCF-7人乳腺癌裸鼠体内分布显示,注射1、4h后,标记物在肿瘤部位的摄取值达(2.38±0.37)%ID/g和(1.57±0.21)%ID/g,瘤/血比分别达0.71±0.09、1.15±0.15,表明该标记物在肿瘤细胞中有一定的摄取和较长的滞留时间。     

N-甲基甲异羟肟酸的合成及其与Np(Ⅳ)、Pu(Ⅳ)配合物稳定常数的测定

以甲酸乙酯和N-甲基盐酸羟胺为主要原料,在乙醇-水体系中合成N-甲基甲异羟肟酸（NMFHA）,并通过元素分析、红外光谱、质谱分析和核磁共振波谱等方法对其结构进行表征。TTA萃取法测定结果表明,在1.0mol/LHNO₃体系中,Np(Ⅳ)、Pu(Ⅳ)与NMFHA形成稳定的1∶2的配合物,其累积稳定常数分别为：β₁(Np(Ⅳ))＝8.83×10⁹,β₂(Np(Ⅳ))＝1.01×10¹⁹;β₁(Pu(Ⅳ))=7.78×10¹⁰,β₂(Pu(Ⅳ))＝5.80×10¹⁹。     

钙钛锆石基组合矿物固溶铈的研究

以ZrSiO₄、CaCO₃、TiO₂、Al₂O₃、Ce₂C₆O₁₂•10H₂O为原料,采用固相反应工艺合成掺Ce钙钛锆石基钛酸盐组合矿物。利用XRD、BSE、EDS等分析方法,研究组合矿物的制备及其对Ce的固溶。结果表明：合成掺Ce钙钛锆石基钛酸盐组合矿物的较佳温度为1230℃;组合矿物的主要晶相为钙钛锆石固溶体,次要晶相是榍石和CaTiO₃的固溶体;CeO₂在组合矿物中的最大固溶量为21.39%;组合矿物固溶Ce⁴⁺的机制较复杂,Ce⁴⁺固溶在Ca²⁺位或Zr⁴⁺位,Al³⁺固溶在Ti⁴⁺位对Ce⁴⁺固溶在Ca²⁺位有电价补偿作用。     

Calculations of Reduced Partition Function Ratios of Hydrated Boric Acid Molecule by the ab initio Molecular Orbital Theory

Based on the ab initio molecular orbital theory at the HF/6-31G(d) level, the effect of hydration on the reduced partition function ratio (RPFR) of the boric acid molecule (B(OH)3) was evaluated in order to better understand boron isotope fractionation observed in aqueous systems. The B(OH)₃(H₂O) _n species with n up to 12 were considered and their geometry optimization and RPFR calculations were carried out. It was induced that hydration decreased the RPFR of B(OH)3 and the degree of decrease in ln(RPFR) was ca. 1.5%, which was nearly equivalent to that of B(OH)₄ ^-.     

Calculations of Reduced Partition Function Ratios of Hydrated Monoborate Anion by the ab initio MoleculaSr Orbital Theory

Based on the ab initio molecular orbital theory at the HF/6-31G(d) level, the effect of hydration on the reduced partition function ratio (RPFR) of the monoborate anion (B(OH)-⁴) is evaluated in order to better understand boron isotope fractionation observed in aqueous systems. Aquoborate anions up to decaaquoborate anion, B(OH)-⁴ (H²O)¹⁰, were considered and their geometry optimization and RPFR calculations were carried out. It was induced that hydration decreased the ln (RPFR) value of B(OH)-⁴ by ca. 1.2%.     

Chromatographic Study on Boron Isotopic Fractionation at High Pressure

Boron isotopic fractionation factor (S) between boron adsorbed onto kaolin clay and boron in aqueous solution was determined by break-through column chromatography at 25.0 MPa at 5 and 25°C. The S values obtained were 1.0021 at 5°C and 1.0011 at 25°C, and were smaller than those obtained by the batch method performed at the atmospheric pressure at room temperature. Theoretical calculations estimate that more than 90% of boron in the clay phase was taken up as B(OH)₃-form at high pressures. Combining the present S values with preliminarily obtained one at 12.0 MPa, it is likely that S value decreases with increasing pressure, which suggests that the difference of the partial isotopic molar volumes between ¹⁰B(OH)₃ and ¹¹B(OH)³ is larger than that of the volumes between ¹⁰B(OH)₄ ^? and ¹¹B(OH)₄ ^?.     

热中子透射法测干玻璃纤维材料含硼量的研究

报道了用热中子透射法测干玻璃纤维材料含硼量的理论计算和实验研究的结果，对于质量为１４、１６、１８、２０、２５ｇ的样品，在含硼量为２％￣１４％范围内，透射率倒数的对数与含硼量间存在线性关系，线性相关系数为０．９９９，测量精度好于０．５％。     

Spectroscopic diagnosis of plasma in atmospheric pressure negative pulsed gasliquid discharge with nozzle-cylinder electrode

The plasma characteristics of a gas-liquid phase discharge reactor were investigated by optical and electrical methods.The nozzle-cylinder electrode in the discharge reactor was supplied witha negative nanosecond pulsed generator.The optical emission spectrum diagnosis revealed that OH(A~2∑~+?→?X~2Π,306–309 nm),N~3_2(CΠ→B~3Π_g,337 nm),O(3p~5p→3s~5s~0,777.2 nm)and O(3p~3p→3s~3s~0,844.6 nm)were produced in the discharge plasma channels.The electron temperature(T_e)was calculated from the emission relative intensity ratio between the atomic O 777.2 nm and 844.6 nm,and it increased with the applied voltage and the pulsed frequency and fell within the range of 0.5–0.8 e V.The gas temperature(T_g)that was measured by Lifbase was in a range from 400 K to 600 K.     

OH and O radicals production in atmospheric pressure air/Ar/H2O gliding arc discharge plasma jet

Atmospheric pressure air/Ar/H_2O gliding arc discharge plasma is produced by a pulsed dc power supply. An optical emission spectroscopic(OES) diagnostic technique is used for the characterization of plasmas and for identifications of OH and O radicals along with other species in the plasmas. The OES diagnostic technique reveals the excitation Tx?≈?5550–9000 K, rotational Tr?≈?1350–2700 K and gas Tg?≈?850–1600 K temperatures, and electron density n?(1.1-1.9) ′101 4 cm~(-3) e under different experimental conditions. The production and destruction of OH and O radicals are investigated as functions of applied voltage and air flow rate. Relative intensities of OH and O radicals indicate that their production rates are increased with increasing Ar content in the gas mixture and applied voltage. nereveals that the higher densities of OH and O radicals are produced in the discharge due to more effective electron impact dissociation of H_2O and O_2 molecules caused by higher kinetic energies as gained by electrons from the enhanced electric field as well as by enhanced n e.The productions of OH and O are decreasing with increasing air flow rate due to removal of Joule heat from the discharge region but enhanced air flow rate significantly modifies discharge maintenance properties. Besides, Tgsignificantly reduces with the enhanced air flow rate. This investigation reveals that Ar plays a significant role in the production of OH and O radicals.     

含硼石墨中甲烷的热解吸行为研究

研究了含硼石墨ＧＢ１１０（１０ｗｔ．％Ｂ）甲烷（ＣＨ４）的热解吸谱,发现甲烷的解吸谱主要由３个峰构成,估算出了ＣＨ４不同峰值的解吸激活能。为了弄清含硼石墨中甲烷的形成与解吸机理,分别对高纯石墨ＩＳＯ８８０Ｕ和Ｂ４Ｃ涂层进行了热解吸实验,同时对材料的微观结构进行了分析。经过比较,表明甲烷在含硼石墨中的形成与解吸有３个过程：氢离子注入导致甲烷沿气孔内壁形成,并通过石墨内部的微通道向表面自由扩散;被石墨中Ｂ４Ｃ析出物所俘获的氢原子与Ｂ４Ｃ化合物中的碳原子反应,从而生成甲烷并解吸出来;以及石墨晶格俘获的氢原子与碳原子化学反应产生的甲烷,通过体扩散过程解吸。其中前后两个过程起主导作用。     

锆铀合金中痕量硼的同位素稀释质谱法测定

本文介绍了用同位素稀释技术测定锆铀合金试样中痕量硼的方法。选用富集~(10)B为同位素稀释剂,用硫酸-硫酸铵溶样,使硼形成挥发的硼酸甲酯与基样分离,用热电离质谱仪进行硼的同位素比值测量。方法的检测下限为1.5ng(硼)。对于含硼量小于1.0μg/g(样)的锆铀合金试样,相对标准偏差小于±1.0%。     

Fundamental experiments on phase stabilities of Fe–B–C ternary systems

To understanding the control blade degradation mechanism of a boiling-water reactor (BWR), a thermodynamic database for the fuel assembly materials is a useful tool. Although the iron, boron, and carbon ternary system is a dominant phase diagram, phase relation data are not sufficient for the region in which boron and carbon compositions are richer than the eutectic composition. The phase relations of three samples such as Fe_0.68B_0.06C_0.26 (at%), Fe_0.68B_0.16C_0.16 (at%), and Fe_0.76B_0.06C_0.18 (at%) were analyzed by X-ray diffraction, scanning electron microscopy, and energy–dispersive X-ray spectrometry. The results indicate that the Fe₃(B,C) phase exists only in the intermediate region at 1273 K and that the solidus temperature widely maintains at approximately 1400 K for all three samples; these results differ from the calculated data using the previous thermodynamic database. The difference might originate from the overestimation of the interaction parameter between boron and carbon in Fe₃(B,C). Proper titling was performed using the present data.