Constraints on the symmetry energy and neutron skins from pygmy resonances in Ni-68 and Sn-132

Correlations between the behavior of the nuclear symmetry energy, the neutron skins, and the percentage of energy-weighted sum rule (EWSR) exhausted by the pygmy dipole resonance (PDR) in Ni-68 and Sn-132 are investigated by using different random phase approximation (RPA) models for the dipole response, based on a representative set of Skyrme effective forces plus meson-exchange effective Lagrangians. A comparison with the experimental data has allowed us to constrain the value of the derivative of the symmetry energy at saturation. The neutron skin radius is deduced under this constraint.

Rare earth complexes with Ge-132 and their catalytic hydrolysis to phosphatide bond of mononucleotide

The complexes of a series of rare earths with Ge-132 have been prepared. The carboxyl anions of Ge-132 molecule were coordinated to rare earth ion with chelate style. In the complexes molecule, the GeO3/2 group of Ge-132 were hydrolyzed to become -Ge(OH)(3) group, and later does:not coordinate with rare earth ions. All of the complexes possess similar properties. In aqueous solution of pH 6 and 50 degrees C, these complexes can obviously selectively catalytically hydrolize the phosphatide bond of 5'-AMP and 5'-dAMP into phosphatic acid and riboside.

The suppression of Ge-132 on the Maillard reaction of BSA by fluorescence spectrum

The fluorescences of BSA and glycosylated BSA were observed respectively. The lambda(cm) of BSA was 340 nm; while the lambda(cm) of glycosylated BSA was 436 nm. Because the fluorescence spectra of them were different greatly, we can observe the suppression of Ge-132 on the Maillard reaction of BSA without any interference of itself. It was showed that the fluorescence intensity of glycosylated BSA increased continuously with the cultured time, Ge-132 may suppress the Maillard reaction of BSA greatly, and the suppressing efficicency would be 32 %. The key site of the Maillard reaction of BSA is free amino groups of alanine residues on N-terminal amino group, besides the epsilon-amino groups of intrachain Lysine residues.

Ge-132稀土配合物及其对单核苷酸磷酯键的催化水解作用

Ｇｅ－１３２是具有广泛生物活性的一元羧酸有机锗倍半氧化物的低聚物，分子中存在类似冠醚的Ｇｅ－Ｏ－Ｇｅ大环结构．因此，有人认为Ｇｅ－１３２的生物活性可能与这种大环结构与体内金属离子形成配合物有关［１］，但尚无直接的实验证据．因此，合成Ｇｅ－１３２稀土配…

荧光法研究Ge-132对牛血清白蛋白Mailard反应的抑制作用

人体内氨基酸及蛋白质的非酶糖化反应（Ｍａｉｌａｒｄ反应）与糖尿病及其并发症的关系已经引起广泛注意［１］．有机锗化合物β－羧乙基锗倍半氧化物（Ｇｅ－１３２）具有预防糖尿病及调节糖代谢的作用［２］．研究Ｇｅ－１３２对Ｍａｉｌａｒｄ反应的抑制作用，对于开发…

荧光法研究 Ge-132 对苯丙氨酸 Maillard 反应的抑制作用

哺乳动物体内氨基酸及蛋白质的非酶糖化反应（Ｍａｉｌａｒｄ反应）与糖尿病及其并发症的关系已引起广泛关注［１］，β－羧乙基锗倍半氧化物（Ｇｅ－１３２）具有预防糖尿病和调节糖代谢的作用［２］，研究Ｇｅ－１３２对Ｍａｉｌａｒｄ反应的抑制作用对于开发防治糖尿病…

Ge-132与稀土离子的配合物及其对单核苷酸磷酯键的催化水解作用

Ge－132的羧酸阴离子与稀土离子螯合配位，生成3：1型配合物。在配合物中，Ge－132的GeO3/2基因水解为Ge（OH）3，并且不参与稀土配位，系列稀土离子配合物的结构性质基本相同，在50℃，pH值为6的水溶液中，该配合物选择性地催化5’－AMP或5’－dAMP的磷酯键水解断裂，生成相应的核苷和磷酸，而不影响碱基与戌糖之1间的苷键。

锗-132的稀土配合物对5'-腺嘌呤及5’-脱氧腺嘌呤核苷酸的水解断裂作用

核酸是重要的生命物质,对核酸序列的选择性切割是当前基因工程的关键问题.在生理条件及非酶存在下,核酸非常稳定(磷酸二酯键在pH 7,25℃时的半衰期为2亿年,因此,近年来研究的人工酶是通过氧化脱氧核糖来切断DNA的,而有关选择性水解断裂核酸的报道则很少,主要困难是缺乏高效的“分子剪刀”,有关稀土对核酸断裂的研究报道尚不多见.作者曾报道了除Ce(Ⅳ)外,其他稀土对5’-腺嘌呤核苷酸(5’-AMP)及5’-鸟嘌呤核苷酸(5’-GMP)均无明显水解作用,并且过去报道的体系为碱性介质,此时稀土以氢氧化物沉淀形式存在为非均相体系,其应用局限性非常大,因此,寻求可溶性的稀土水解核酸体系就显得非常重要.本文用核磁共振(NMR)和化学法研究了Yb-Ge-132和Pr-Ge-132配合物对5’-AMP及5’-dAMP的断裂作用,指出Yb-Ge-132和Pr-Ge-132使5’-AMP水解为腺苷(A)及无机磷,使5’-dAMP水解为脱氧腺苷(dA)及无机磷,其断裂机制为水解断裂,这对于研究稀土与核酸的作用,寻找新的核酸均相水解体系都具有非常重要的意义.

Energy Conversion in Shape Memory Alloy Heat Engine Part I: Theory

Shape Memory Alloy (SMA) can be easily deformed to a new shape by applying a small external load at low temperature, and then recovers its original configuration upon heating. This unique shape memory phenomenon has inspired many novel designs. SMA based heat engine is one among them. SMA heat engine is an environment-friendly alternative to extract mechanical energy from low-grade energies, for instance, warm wastewater, geothermal energy, solar thermal energy, etc. The aim of this paper is to present an applicable theoretical model for simulation of SMA-based heat engines. First, a micro-mechanical constitutive model is derived for SMAs. The volume fractions of austenite and martensite variants are chosen as internal variables to describe the evolution of microstructure in SMA upon phase transition. Subsequently, the energy equation is derived based on the first thermodynamic law and the previous SMA model. From Fourier’s law of heat conduction and Newton’s law of cooling, both differential and integral forms of energy conversion equation are obtained.

Modified Generalized Beam Lattice Model Associated With Fracture Of Reinforced Fiber/Particle Composites

Lattice-type model can simulate in a straightforward manner heterogeneous brittle media. Mohr-Coulomb failure criterion has recently been involved into the generalized beam (GB) lattice model, and as a result, numerical experiments on concrete under various loading conditions can be conducted. The GB lattice model is further used to investigate the reinforced fiber/particle composites instead of only particle composites as the model did before. Numerical examples are given to show the effectiveness of the modeling procedure, and influences of inclusions (particle, fiber and rebar) on the fracture processes are also discussed. (c) 2008 Elsevier Ltd. All rights reserved.

ADI方法求解Navier-Stokes方程的一个改进格式

ADI方法常被用来计算不可压缩Navier-Stokes方程。在处理涡度方程的非线性项和涡度在壁面上的条件时,通常采用滞后的方法对涡度方程和流函数方程分别求解。然而,非线性项的滞后破坏了ADI方法的完全二阶精度;涡度方程和流函数方程分别求解减弱了两个方程的耦合性;涡度壁面条件的滞后则破坏了方法的完全隐式。本文在应用ADI方法求解涡度方程和流函数方程时应用了一种交替线性化的技术,对涡度方程和流函数方程耦合求解,内点和边界点上的涡度和流函数值同时求出。因此,ADI方法保持了完全的二阶精度,避免了上面所提到的问题。作者应用这一方法计算了雷诺数R_θ等于1,10,100,500,1000时的二维方腔流动(空间步长h=1/20)。计算结果表明:这一方法保持了通常ADI方法的优点,可以应用大的时间步长。最后补充计算了雷诺数R_θ=2000的二维方腔流动。

Effect of phase-transformation on mechanical-behavior of dual-phase steel plate

The mechanical behavior of dual phase steel plates is affected by internal stresses created during martensite transformation. Analytical modelling of this effect is made by considering a unit cell made of martensite inclusion in a ferrite matrix. A large strain finite element analysis is then performed to obtain the plane stress deformation state. Displayed numerically are the development of the plastic zone and distribution of local state of stress and strain. Studied also are the shape configuration of the martensite (hard-phase) that influences the interfacial condition as related to stress transmission and damage. Internal stresses are found to enhance the global flow stress after yield initiation in the ferrite matrix. Good agreement is obtained between the analytical results and experimental observations.