Preparation of gelatinous aluminium hydroxide by urea from aqueous solutions containing chloride,nitrate and sulphate of aluminium

The preparation of gelatinous aluminium hydroxide from aqueous solutions containing a mixture of the chloride, nitrate or sulphate of aluminium and urea by heating at 95°C has been investigated under different conditions. The pH value of aqueous solutions, on heating for a given period of time, gradually increases, rises steeply at pH 4.0–7.5 and finally approaches a constant value. The precipitate appears at about pH 7 in the presence of chloride or nitrate ions and about pH 4 in the presence of sulphate ions. Although the gelatinous precipitates in the chloride and nitrate systems are apparently different from the granular, filterable one in the sulphate system, their compositions are not influenced by the species of aluminium salt. The fresh precipitates exist in an amorphous state, and go to pseudoboehmite by ageing. It seems that the amount of pseudoboehmite increases as the concentration of aluminium salt in aqueous solution decreases. However, the transformation from amorphous aluminium hydroxide to pseudoboehmite is reduced in the presence of sulphate ions. Furthermore, it is found that the X-ray diffraction peak for the (200) plane, as an orthorhombic structure, in the pseudoboehmite precipitated from chloride or nitrate solution is more intense than that from sulphate solution.     

Proposal for selective isotope transmutation of long-lived fission products using quasi-monochromatic γ-ray beams

We have proposed a new selective isotope transmutation method using photonuclear reactions with quasi-monochromatic γ-ray beams. This method is based on the fact that the particle threshold of a long-lived fission product (LLFP) such as ⁹³Zr, ¹⁰⁷Pd, or ⁷⁹Se is lower than those of stable isotopes of the same chemical element. Therefore, this method has the excellent advantage that LLFPs cannot, in principle, be produced newly even if the target materials include stable isotopes in addition to LLFPs. Furthermore, this method is effective for ¹²⁶Sn, ^{135, 137}Cs, ⁹⁰Sr, and ³H. The nuclear data involved and suitable γ-ray sources are discussed. Laser Compton scattering γ-ray sources and neutron capture γ-rays in nuclear reactors are candidates for this method.     

K-ras and p53 mutations in stage I gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct

BACKGROUND: An anomalous junction of the pancreaticobiliary duct (AJPBD) was thought to be an important risk factor for gallbladder carcinoma in Japan. In this report, we compared K-ras and p53 mutations in Stage I gallbladder carcinomas (GC) of patients with AJPBD with those in patients without AJPBD: METHODS: We examined 6 GC of patients with AJPBD and 20 GC of patients without AJPBD: Immunohistochemistry was performed for p53 protein. K-ras and p53 mutations were examined using genomic DNA extracted from the cancer regions. The methods of polymerase chain reaction (PCR) single strand conformation polymorphism analysis were performed for mutations in exons 5-8 of p53. The methods of PCR restriction fragment length polymorphism were performed for mutation in codon 12 of K-ras. RESULTS: p53 positivity was 67% in GC of patients with AJPBD and 65% in GC of patients without AJPBD: p53 mutations were found in exons 7 and 8 in GC of patients with AJPBD and in exons 5, 6, and 7 in GC of patients without AJPBD: The incidence of K-ras mutation in GC of patients with AJPBD (50%) was greater than that in patients without AJPBD (6%) (P < 0.05). CONCLUSIONS: These results suggest that K-ras mutation may be important in the early stage of carcinogenesis of the gallbladder mucosa with AJPBD, and that p53 mutations may also contribute to the early stage of carcinogenesis of the gallbladder mucosa, regardless of AJPBD:     

Deformation of metastable betaTi-15Mo-5Zr alloy single crystals

Deformation modes have been investigated in metastable beta Ti-15Mo-5Zr alloy single crystals using both transmission electron microscopy techniques and multisurface trace analysis. {332} twinning and 〈111〉 crystallographic slip were observed to occur at an initial stage of deformation depending on deformation axis. {332} twinning occurs in a crystal whose tensile axis lies around 〈111〉, while 〈111〉 slip appears in a crystal having the tensile axis in the neighborhood of 〈001〉 to 〈011〉. The twinning system which possesses the maximum resolved shear stress is always operative in both tensile and compressive deformations. Single crystals of this alloy exhibit an asymmetry of the active slip plane and of the yield stress in a manner similar to other bcc metals and dilute alloys.     

ICP-MS法测定地电化学(泡塑)样品中痕量金

通过实验验证了在酸性介质存在条件下用ICP-MS法测定地电化学(泡塑)样品中痕量金的可行性,在稀释因子存在条件下得到了方法的检出限为3 ng、精密度为1.40％.同时,通过制备模拟负载不同金含量的泡塑样品,计算加入标准物质回收率为88.80％～107.37％;与GAAS法测定结果进行显著性检验发现两组数据之间无显著性差...     

X射线激光Nd，Dy,Er和Yb薄膜靶表面氧化过程的石英晶振方法研究

用电子束蒸发方法在抛光玻璃衬底上分别制备了X射线激光用的稀土元素Nd ,Dy ,Er和Yb薄膜靶。用石英晶片作为陪片 ,通过测量晶振频率的方法研究了薄膜靶在真空、干燥空气及潮湿空气等不同环境中不同阶段的氧化层增长过程。发现除Yb薄膜在淀积结束后的干燥空气和潮湿空气环境中的氧化过程遵循倒对数规律之外 ,其它所有的氧化过程均可用对数规律很好地进行拟合。淀积结束后充入大气时 ,薄膜表面的快速氧化过程仅为数分钟。在相同的环境中 ,Nd氧化速率最高 ,Er和Dy其次 ,Yb最低 ;在不同的环境中 ,Nd受环境湿度的影响最大 ,Er和Dy其次 ,Yb最低。     

Cellulose nanofibrils as templates for the design of poly(l-lactide)-nucleating surfaces

The abilities of surface-grafted cellulose nanofibrils for the nucleation of poly(l-lactide) (PLLA) were investigated. Cellulose nanofibrils with a width of ∼3 nm were obtained from wood cellulose via the oxidation using 2,2,6,6-tetramethylpiperidiniyl-1-oxyl as a catalyst and successive mechanical treatment. The cellulose nanofibril surfaces were selectively modified with amine-terminated poly(ethylene glycol) chains, via simple ionic bonds. The PEG-grafted cellulose nanofibril/PLLA composite films were prepared using a solvent casting method with chloroform. The isothermal and non-isothermal crystallization kinetics of the PLLA in the composites was studied using differential scanning calorimetry and polarized optical microscopy. The PEG chains were densely immobilized on the surface of the cellulose nanofibril templates, which had extraordinarily large specific surface areas. As a result, the surface-PEG layers effectively increased the rate of crystallization of the PLLA in the composites. Because of the increased degree of crystallinity after the isothermal crystallization, the composites showed better heat resistance than neat PLLA.     

Trap Levels in Eu and other Rare‐Earth Ions Codoped CaAl2O4 Phosphors

Photoluminescence spectrum, trap depths, and densities of trapped carriers of CaAl₂O₄:Eu phosphor crystals doped with rare‐earth elements were studied using the thermally stimulated luminescence technique. Trap depths and densities of the specimens vary with rare‐earth elements doped as the auxiliary activators. Tm and Nd are found to be effective for the strong afterglow phosphorescence peaking at λ = 442 nm for several hours after the excitation. CaAl₂O₄:Eu phosphor crystals doped with Nd and Tm include high density of carriers trapped at E = 0.59 and 0.52 eV, respectively.