放射性(~(110)Ag~m)Ag/TiO_2复合纳米微粒的研制

用钛酸四正丁酯水解法制备了纳米TiO2溶胶,并通过光化学沉积的方法制备Ag/TiO2复合纳米微粒。研究了浓度、pH值、乙醇等条件对复合物形成的影响,在此基础上用放射性的110Agm制备了放射性(110Agm)Ag/TiO2复合纳米微粒。实验结果表明在最佳反应条件下,用聚酰胺薄膜层析法测得约有93.6%的110Agm沉积在TiO2纳米微粒表面,放射性浓度为0.6MBq/mL;放置48小时后仍有93.0%的110Agm沉积在TiO2纳米微粒表面;经原子力显微镜测定,TiO2微粒和Ag/TiO2复合微粒的粒径分别为1—2nm和8—40nm。     

~(103)Pd-~(125)I复合粒子源芯制备工艺中化学沉积银过程的研究

采用表面均匀覆盖钯层的0.5mm×3.0mm碳棒为载体,以银氨溶液为前体,110mAg为放射性示踪剂,水合肼为还原剂,在载体棒表面依次进行化学沉积103Pd、Ag、125I,可制备新型103 Pd-125I复合粒子源芯,实现103Pd和125I在同一载体表面的有效沉积,化学沉积银过程是103 Pd-125I复合粒子制备的关键。经优化的沉积条件为:AgNO3浓度2g/L,Na2EDTA浓度40g/L,NH3·H2O浓度16.25%,H4N2·H2O浓度5‰,沉积液pH10,反应时间60min,反应温度35℃。结果表明:化学沉积银层表面均匀,平整,呈银白色。     

磁性纳米微粒的制备方法及其在放射免疫分析中的初步应用

采用化学共沉淀法合成水溶性正癸酸包覆的Fe3O4磁性纳米微粒,并以此为核心物理吸附羊抗兔IgG制备磁性纳米第二抗体,作为磁性分离载体用于放射免疫分析中。用光子相关光谱仪与透射电镜测定了磁性纳米微粒的粒径大小、粒径分布和多分散度等。研究了羊抗兔IgG包被磁性纳米微粒的包被介质的pH、羊抗兔IgG用量和包被时间等制备条件对磁性纳米微粒二抗免疫反应结合能力和非特异结合的影响。结果表明：化学共沉淀法制得的Fe3O4平均粒径约为10-20nm,吸附羊抗兔IgG后其平均粒径为1000nm左右,并可用于放射免疫分析中。提示羊抗兔IgG可通过物理吸附的方法固定在磁性纳米微粒上,其优点是制备方法简便、省时和成本低,在放射免疫分析中具有磁性分离的方便性,具有较大的医学应用价值。     

钴氧化物纳米催化剂的制备及对N2O的分解

用微乳液法制备了表面经硬脂酸（ST）修饰的4种不同价态的钴氧化合物纳米微粒。初步摸索了合成的最佳条件，利用XRD，TEM，IR等测试手段对制备的钴纳米催化剂的物相、粒子的形貌和粒度及钴氧化物纳米微粒与表面活性剂有机基团间的结合方式进行了表征，结果表明制得的纳米微粒呈球状、粒度随热处理温度升高而增大，COO－与Co(Ⅱ，Ⅲ）离子间以化学键相结合。利用流动法固定床反应器研究了钴氧化物纳米催化剂对N2O的催化分解活性，实验结果表明，在350℃焙烧制得的Co2O3纳米粒子对N2O的催化分解有较好的催化活性。     

6 加速器生产加^109Cd用Ag靶制备

Ag靶用于加速器生产^109Cd，核反应为^109Ag（p，n）^109Cd。本工作采用电沉积法制备Ag靶。通过对影响电沉积Ag靶层质量及厚度的各种因素的实验，确定了Ag靶制备工艺条件如下：ρ（Ag^＋）=20～50g／L，ρ（KNO3）=10-30g／L，φ（NH4OH）=0．1～0．2。用此工艺条件，制备出质量厚度大于100mg／cm^2、表面光滑、镀层致密的Ag靶。     

SiO_2纳米干凝胶的合成和表征

以水玻璃和盐酸为原料，通过添加表面活性剂的方法制备SiO2纳米干凝胶，并对其制备条件进行了研究；用BET，DTA－TGA，IR，XRD，TEM等手段对样品的结构和性能进行了表征。结果表明，合成SiO2纳米干凝胶的最佳工艺条件为：水玻璃质量浓度，40g/L；盐酸浓度,5mol/L；表面活性剂质量浓度，50g/L；老化时间，1h；煅烧温度，600℃。该样品的比表面积可达998m^2/g，对锆的静态吸附容量为0．344mmol/g。     

电子束辐照制备的纳米硫化镉研究

在常温常压下，采用电子束辐照法在水溶液体系中合成了纳米硫化镉粒子。X射线衍射分析表明该产物为面心立方结构晶体的纳米硫化镉；透射电子显微镜分析表明该纳米粒子形貌呈球状颗粒，平均粒径为15nm；其光学性能研究表明，其紫外吸收光谱的吸收边波长为487nm；激发波长为350nm时，纳米粒子的荧光发射波长的峰值为476nm，主要为由带边发射引起的发光。用激光粒度仪研究了表面活性剂聚乙烯醇浓度对辐射制备纳米硫化镉粒径的影响，在一定范围内随着聚乙烯醇浓度的增大，纳米粒子的粒径相应减小。     

103Pd-110Agm合金膜制备工艺研究

以103Pd和110Agm 为示踪剂,采用化学镀法制备了103Pd-110Agm合金膜,并优化了制备条件：对制得的103Pd-110Agm合金膜采用γ井型探测器进行定量分析,扫描电镜进行定性分析。结果显示,优化后的镀膜条件为：镀液组成为PdCl2(含放射性103Pd) 、AgNO3、Na2EDTA、NH3 、N2H4;Pd与Ag的摩尔比为9∶1;活化液PdCl2的浓度范围为0.5～2.0 mmol/L;金属离子总浓度为5～7 mmol/L;NH3浓度为2～4 mol/L;pH为10～12;N2H4浓度为10 mmol/L;Na2EDTA浓度为0.15 mol/L;恒温水浴槽保持温度为60 ℃,旋转搅拌器转速为40～60 r/min,反应时间为60 min。在以上镀膜条件下进行化学镀,可得到具有金属光泽的镀层。用载体预处理后,扫描电镜显示,镀层表面有晶粒生长,镀后清晰可见;定性分析结果表明,合金膜中有Pd、Ag元素存在。     

掺Fe纳米Ti02的结构

本采用溶胶-凝胶法，获得了铁掺杂的纳米TiO2样品，XRD和透射电镜测量表明在600℃以下焙烧时为锐钛矿，颗粒度在10nm以下，样品在1000℃下焙烧时，转变为金红石相，颖粒度增大。EXAPS和穆谱表明，铁的确掺杂到TiO2晶格内，表现为3价。铁的掺杂改变了纯的TiO2的性质，对于锐铁矿相的掺铁纳米TiO2，其紫外-可见反射光谱给出在481nm处出观了新的吸收峰，；对于以金红石相为主的掺铁纳米TiO2，其紫外-可见反射光谱在512nm处出现了新的吸收峰。     

碳纳米管的放射性材料填充

开口纯化后的碳纳米管(CNTs)用放射性(^125I)NaI和(^110Ag^m)AgNO3溶液进行了浸泡、洗涤和洗脱研究，用高分辨透射电镜(HREM)和X射线散射能谱(EDS)对CNTs的填充情况进行了表征；使用放射性同位素示踪技术确定了CNTs内部样品的填充量。结果显示用本工作所采用的简单水溶液浸泡技术能将水溶性无机盐材料填充到CNTs中空结构内。实验表明，放射性核素示踪技术能有效地应用于CNTs的填充、释放等行为的研究。     

Thermal expansion studies on UMoO5, UMoO6, Na2U(MoO4)3 and Na4U(MoO4)4

In the present work, thermal expansion behavior of lower valent sodium uranium molybdates, i.e., Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄ were studied under vacuum in the temperature range of 298-873 K using high temperature X-ray diffractometry (HTXRD). Expansion behaviors of UMoO₅ and UMoO₆ were also studied in vacuum from 298 to 873 K and 773 K, respectively. UMoO₅ was synthesized by reacting UO₂ with MoO₃ in equi-molar proportion in evacuated sealed quartz ampoule at 1173 K for 14 h. Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄ were prepared by reacting UMoO₅ and MoO₃ with 1 and 2 moles of Na₂MoO₄, respectively, at 873 K in evacuated sealed quartz ampoule. XRD data of UMoO₅ and UMoO₆ were indexed on orthorhombic and monoclinic systems, respectively, whereas, the data of Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄ were indexed on tetragonal system. The lattice parameters and cell volume of all the four compounds, fit into polynomial expression with respect to temperature, showed positive thermal expansion (PTE) up to 873 K.     

Thermophysical properties of NpO2, AmO2 and CmO2

The information on thermal and mechanical properties of the minor actinide dioxides: NpO₂, AmO₂ and CmO₂, is still very scarce, and a large uncertainty exists because of difficulties related to their fabrication and manipulation. Prognosis based on a set of the sound physical models and the similarity principle can be useful in this situation. Using the combination of the macroscopic and microscopic approaches developed earlier for thermodynamic properties of actinide dioxides, and the Klemmens model for their thermal conductivity, a few relationships bounding the main thermophysical properties of the actinide dioxides were deduced. These relationships were applied for the calculation of the isochoric and isobaric heat capacity, the isobaric thermal expansion coefficient, the isothermal bulk elastic modulus and the thermal conductivity of NpO₂, AmO₂ and CmO₂ in a large temperature range. A rather satisfactory agreement with the available experimental data and recommendations was demonstrated.     

HfO2 and Ta2O5 as grain growth inhibitors in Eu2O3

Because of the high neutron capture cross section for five consecutive europium isotopes, Eu₂O₃ is of interest as a control material for nuclear reactors. A tendency toward excessive grain growth degrades its mechanical properties. Small amounts of HfO₂ and Ta₂O₅ were added to the Eu₂O₃ in attempts to suppress this grain growth. Three at % substitution of Hf for     

Formation of U2C3 in the reaction of UC2 with UO2

The formation of U₂C₃ by the reaction of UC₂ with UO₂ has been studied by chemical and X-ray analyses at temperatures between 1400 and 1700 °C in vacuo. The reaction is represented by 7 UC₂ + UO₂ → 4 U₂C₃ + 2 CO.     

Reactivity of hydrogen peroxide towards Fe3O4, Fe2CoO4 and Fe2NiO4

The kinetics of CRUD oxidation by H₂O₂ has been studied using aqueous suspensions of metal oxide powder. Fe₃O₄, Fe₂CoO₄ and Fe₂NiO₄ were used as model compounds for CRUD. In addition, the activation energies for the reaction between H₂O₂ and the three CRUD models were determined. The rate constants at room temperature were determined to 6.6 (±0.4) × 10⁻⁹, 3.4 (±0.4) × 10⁻⁸ and 1.6 × 10⁻¹⁰ m min⁻¹ for Fe₃O₄, Fe₂CoO₄ and Fe₂NiO₄, respectively. The corresponding activation energies are 52 ± 4, 44 ± 5 and 57 ± 7 kJ mol⁻¹, respectively. The mechanism of the reaction is briefly discussed indicating that the final solid product in all three cases is Fe₂O₃. In addition to the experimental studies, the theoretical grounds for kinetics of reactions in particle suspensions are discussed. The theoretical discussion is also used to explain the somewhat unexpected trends in reactivity observed experimentally.     

Reduction of UO2 by H2

The reactivity of H₂ towards UO₂²⁺ has been studied experimentally using a PEEK coated autoclave where the UO₂²⁺ concentration in aqueous solution containing 2 mM carbonate was measured as a function of time at p_H2∼40 bar. The experiments were performed in the temperature interval 74-100 °C. In addition, the suggested catalytic activity of UO₂ on the reduction of UO₂²⁺ by H₂ was investigated. The results clearly show that H₂ is capable of reducing UO₂²⁺ to UO₂ without the presence of a catalyst. The reaction is of first order with respect to UO₂²⁺. The activation energy for the process is 130 ± 24 kJ mol⁻¹ and the rate constant is k_298K=3.6×10⁻⁹ l mol⁻¹ s⁻¹. The activation enthalpy and entropy for the process was determined to 126 kJ mol⁻¹ and 16.5 J mol⁻¹ K⁻¹, respectively. Traces of oxygen were shown to inhibit the reduction process. Hence, the suggested catalytic activity of freshly precipitated UO₂ on the reduction of UO₂²⁺ by H₂ could not be confirmed.     

One-Dimensional Fluid Model of Pulse Modulated Radio-Frequency SiH4 /N2 /O2 Discharge

Driven by pulse modulated radio-frequency source,the behavior of SiH 4 /N 2 /O 2 plasma in capacitively coupled discharge are studied by using a one-dimensional fluid model.Totally,48 different species(electrons,ions,neutrals,radicals and excited species) are involved in this simulation.Time evolution of the particle densities and electron temperature with different duty cycles are obtained,as well as the electronegativity n SiH3 /n e of the main negative ion(SiH3).The results show that,by reducing the duty cycle,higher electron temperature and particle density can be achieved for the same average dissipated power,and the ion energy can also be effectively reduced,which will offer evident improvement in plasma deposition processes compared with the case of continuous wave discharge.     

High-temperature specific heat of UO2 ThO2, and A12O3

The high-temperature specific heat of solid UO₂, ThO₂, and Al₂O₃ can be represented by an equation of the form $\text{C}{}_{\mathrm{p(s)}}\text{= 3}{}_{\mathrm{n}}\text{RF(?}{}_{\mathrm{D}}\text{/T) + dT}{}^3$, (1) where ?_D is the Debye temperature, F(?_D/T) is the Debye function, $\text{d}$ represents contributions of the anharmonic vibrations within the lattice, and $\text{n}$ denotes the number of atoms per molecule. In the liquid the corresponding equation is $\text{C}{}_{\mathrm{p(1)}}\text{= 3}{}_{\mathrm{n}}\text{RF(?}{}_{\mathrm{D}}\text{/T) +}\text{h}\text{T}{}^2$, (2) where h is the anharmonic term. It is shown that for Al₂O₃ and UO₂, where experimental data for the liquid phase are also available, $\text{d}\text{h}$ has the same value, Indicating that both materials behave identically. If we compare the thermodynamic relationship $\text{C}{}_{\mathrm{p}}\text{? C}{}_{\mathrm{v}}\text{= Vα}{}^2\text{KT}$, (3) where V is the volume, $\text{α}$ the volume expansion coefficient, and $\text{K}$ the bulk modulus, with equation (1), It follows that d must be equal to $\text{Vα}{}^2\text{K}\text{T}{}^2$; the value of $\text{Vα}{}^2\text{K}\text{T}{}^2$ is calculated in the temperature region where d was obtained; within experimental error they are equal.     

含TBP-HNO3超临界CO2流体静态络合萃取U3O8

建立了一种快速降低萃取系统压力的静态络合萃取实验装置。在此装置上研究了含TBP-HNO₃超临界CO₂静态络合U₃O₈的快速气化测量方法,探索了含TBP-HNO₃超临界CO₂静态络合萃取U₃O₈的行为规律。