紫外吸收光谱法和电化学法研究原儿茶醛与牛血清蛋白的相互作用及共存金属离子的影响

利用紫外可见吸收光谱法和电化学法研究了中药小分子原儿茶醛与牛血清蛋白的相互作用,考察了温度和共存金属离子Cu~(2+),Ni~(2+),Zn~(2+)对二者结合常数的影响情况,计算了原儿茶醛与牛血清蛋白作用过程的ΔG,ΔH,ΔS。结果显示,原儿茶醛与牛血清蛋白的结合常数随着温度的升高和金属离子的存在都有不同程度的降低,二者的结合是一个焓和熵共同驱动的自发过程,之间的作用力主要表现为静电引力。运用循环伏安法测试了原儿茶醛与牛血清蛋白相互作用的电化学行为,结果表明,原儿茶醛与牛血清蛋白结合位点数为1,两者之间形成一种电活性的超分子化合物。     

固态发酵-水煮耦合炮制牛蒡子提高牛蒡子苷元含量

研究了黑曲霉Aspergillus niger ZJUT712菌株固态发酵和水煮工艺相耦合炮制牛蒡子. 结果表明,该工艺提高了牛蒡子中有效成分牛蒡子苷元的含量,从而有利于促进牛蒡子摄入体内迅速起效. 最佳固态发酵炮制条件为: 0.5 g牛蒡子粉、 3 g麸皮、 2 g甘蔗渣、 0.3 g蛋白胨和10 ml Mandels营养液,固液比1∶3.6 g/ml, 初始pH 5.6, 30 ℃发酵 7 d. 牛蒡子苷元产率随底物初始浓度的增加而降低. A.niger ZJUT712转化0.174 mmol/L牛蒡子苷的产率可达93.0%. 7 d时间内A.niger ZJUT712水解牛蒡子苷的过程符合Monod方程,反应动力学常数为Vm=0.083 7 mmol/(L·d), Km=0.16 mmol/L.     

壳管相变蓄热器强化传热实验研究

为了强化相变蓄热器传热性能,本文设计了三种新型壳管相变蓄热器结构,并对其换热性能进行实验研究。结果表明:在蓄热器内部添加分层结构和斜翅片换热性能最高,内部温度达到均匀化的时间随换热单元数增加而增大;换热管道间翅片的添加可有效地强化换热效果,改善蓄热器内部出现的温度严重分层现象,温度分布更加均匀;在研究范围内,换热流体温度的增加可有效提高蓄热器的换热效率,缩短相变时间。     

The giant enhancement of Fano-type resonance in a gain-assisted silicon slab array

Giant resonance enhancement is demonstrated to be due to the Fano interference in a grating waveguide composed of gain-assisted silicon slabs. The Fano mode is characterized by its ultra-narrow asymmetric spectrum, different from that of a pure electric or magnetic dipole. The simulation indicates that a sharp Fano-interfered lineshape is responsible for the giant resonance enhancement featuring the small-gain requirements.     

The metamaterial analogue of electromagnetically induced transparency by dual-mode excitation of a symmetric resonator

Electromagnetically induced transparency （EIT） is obtained in a symmetric U-shaped metamaterial, which is at- tributed to the simultaneously excited dual modes in a single resonator under lateral incidence. A large group index accom- panied with a sharp EIT-like transparency window offers potential applications for slowing down light and sensing.     

Spin transport in epitaxial Fe3O4/GaAs lateral structured devices

Research in the spintronics community has been intensively stimulated by the proposal of the spin field-effect transistor (SFET), which has the potential for combining the data storage and process in a single device. Here we report the spin dependent transport on a Fe₃O₄/GaAs based lateral structured device. Parallel and antiparallel states of two Fe₃O₄ electrodes are achieved. A clear MR loop shows the perfect butterfly shape at room temperature, of which the intensity decreases with the reducing current, showing the strong bias dependence. Understanding the spin-dependent transport properties in this architecture has strong implication in further development of the spintronic devices for room-temperature SFETs.     

浅介2007年诺贝尔物理学奖与自旋电子学

2007年10月瑞典皇家科学院宣布,将该年度诺贝尔物理学奖授予在1988年分别独立发现纳米多层膜中巨磁电阻的法国Albert Fert教授和德国Peter Grtinberg教授。     

The study of the shape anisotropy in patterned permalloy films

In this paper a systematic ferromagnetic resonance study shows that an in-plane magnetic anisotropy in the patterned micron octagon permalloy (Ni透磁合金;定型薄膜;形状各向异性;铁磁共振patterned film, shape anisotropy, ferromagnetic resonanceProject supported by the National Natural Science Foundation of China (Grant No~50171020) and the Foundation for youth of Liaocheng University (Grant No~X051050).1/5/2007 12:00:00 AMIn this paper a systematic ferromagnetic resonance study shows that an in-plane magnetic anisotropy in the patterned micron octagon permalloy （Ni80Fe20） elements is mainly determined by the element geometry. The easy-axis is along the edge of the elements, and the hard-axis is along the diagonal. The shape anisotropy of the octagon elements is determined by square and equilateral octagon, and the theoretical calculation was studied on the shape anisotropy. The shape anisotropy of rectangular was calculated by using the same theory.     

EuMo_6S_8的超导性、电荷密度波和磁性间的相互影响

我们已观察到在120K时Eu_(1.2)Mo_6S_8的热容量、电阻及霍尔系数的反常规象,并确定为一种马氏体结构的相变特征;这种马氏体结构相变产生于一种模糊的电荷密度波的转变,后者在部分费米面上造成能隙。 费米面出现部分能隙说明了在常压下直10mK不出现超导的原因。高压抑制了电荷密度波的转变。从费米面上状态的超导性和这种转变相互竞争出发,计算得到的超导转变温度对压力的依赖性,与实验结果非常一致。在低温时,临界场随温度的变化非常强烈,这种变化已用Jaccarino-Peter补偿效应进行了解释。在高压时与理论的预言比较,EuMo_6S_8的临界场非常高,至少与现有任何的超导体一样高。压力为14Kbar、温度低于2K时在10T到15T范围内已观察到低场下电阻态到超导态的转变,这就是称之为场诱导超导性的一种新效应。     

Effects of switching pulse width and stress on properties of Bi3.25La0.75Ti3O12 thin films

Polycrystalline ferroelectric Bi3.25La0.75Ti3O12 thin films are prepared on Pt/Ti/SiO2/Si substrates by the conventional metalorganic decomposition method.It is observed that with the increase of switching pulse width,the remnant polarisation and the coercive field increase.A wider switching pulse can result in poorer fatigue properties,which comes from more charged defects diffusing to and being trapped on domain walls.On the other hand,when the compressive stress is applied to films,the fatigue properties can be improved.This phenomenon is due to the reorientation of domains under stress.