Ensembles of indium phosphide nanowires: physical properties and functional devices integrated on non-single crystal platforms

A new route to grow an ensemble of indium phosphide single-crystal semiconductor nanowires is described. Unlike conventional epitaxial growth of single-crystal semiconductor films, the proposed route for growing semiconductor nanowires does not require a single-crystal semiconductor substrate. In the proposed route, instead of using single-crystal semiconductor substrates that are characterized by their long-range atomic ordering, a template layer that possesses short-range atomic ordering prepared on a non-single-crystal substrate is employed. On the template layer, epitaxial information associated with its short-range atomic ordering is available within an area that is comparable to that of a nanowire root. Thus the template layer locally provides epitaxial information required for the growth of semiconductor nanowires. In the particular demonstration described in this paper, hydrogenated silicon was used as a template layer for epitaxial growth of indium phosphide nanowires. The indium phosphide nanowires grown on the hydrogenerated silicon template layer were found to be single crystal and optically active. Simple photoconductors and pin-diodes were fabricated and tested with the view towards various optoelectronic device applications where group III–V compound semiconductors are functionally integrated onto non-single-crystal platforms.     

Intense THz-radiation from semiconductors under magnetic field irradiated with femtosecond laser pulses

The THz-radiation power from InAs reaches sub-mW level in a 1.7-T magnetic field irradiated with femtosecond laser pulses of 1.5-W average power. The THz-radiation power is related almost quadratically both to the magnetic field and to the excitation laser power. Furthermore, the THz-radiation spectrum is found to be controlled by the excitation pulsewidth, chirp direction of the excitation pulse, and the magnetic field.     

逃逸函数算法及其在光学设计中的应用

用阻尼最小二乘法进行光学系统的优化 ,得到的结果往往是评价函数在结构变量空间的一个局部极小值。日本东京工艺大学的一色教授提出了能够跳出此局部极小值继续寻找其它结果的逃逸函数全局优化算法 ,该算法的运行由多个不加或加入逃逸函数的阻尼最小二乘法局部优化组成。描述了逃逸函数的基本原理 ,给出了北京理工大学研制的GOLD软件在加入了这种算法后对光学系统进行全局优化的设计实例。实验证明了逃逸函数算法是提高光学设计效率和质量的一种有效工具。     

Conformation-controlled luminescent properties of lanthanide clusters containing p-tert-butylsulfonylcalix[4]arene

Dinuclear and cubane-shaped lanthanide cluster complexes containing EuIII)and TbIII were synthesized by step-by-step construction using p-tert-butylsulfonylcalix[4]arene as a cluster-forming ligand. The sulfonylcalixarene adopts a pinched-cone conformation in the dinuclear complexes and a cone conformation in the cubane complexes. Because the calixarene has a large pi-conjugate system expanding over the entire molecule, it behaves as a good antenna chromophore for UV and near-UV light, and a slight conformational change of the calixarene (from cone to pinched-cone and vice versa) has an effect on the energy levels of excited S1 and T1 states. As a result, selectivity is observed in the luminescent properties of dinuclear and cubane-shaped systems of EuIII and TbIII.     

Rational assembly of a 3D metal-organic framework for gas adsorption with predesigned cubic building blocks and 1D open channels

A novel 3D metal-organic framework with predesigned cubic building blocks and 1D open channels exhibiting significant N2 adsorption has been synthesized and characterized by single crystal X-ray diffraction analysis.     

Synthesis,structure, and ferromagnetic behavior of decacopper(II) cluster complex supported by hexaanionic p-tert-butylthiacalix[6]arene

A nanosized decacopper(II) cluster complex was synthesized using p-tert-butylthiacalix[6]arene as a ligand. In the complex, the calixarene assumes a "pinched cone" conformation and acts as an undecadentate ligand via six phenoxy oxygen and five sulfur atoms. The resulting pentacopper(II) subunits are connected by two hydroxo and two oxo groups to form decacappoer(II) cluster core. The core structure remains intact in alcoholic solution as shown by ESI MS. The temperature dependence of chimT clearly shows ferromagnetic behavior of the core due to orthogonality between two adjoining magnetic orbitals of copper(II) ions.     

Trace determination and characterization of some proteins in blood serum by high-performance liquid chromatography with a time-resolved laser fluorimetric detector

Protein in human serum is measured by high-performance liquid chromatography with a time- resolved laser fluorimetric detector. The detection limit is 2.3 pmol for bovine serum albumin; the value is governed by fluctuation of the background fluorescence from free 1-anilino-8-naphthalene sulfonate (ANS) used as the fluorescence probe. Micropolarity of the binding site in protein is estimated by measuring the fluorescence lifetime of ANS bound to protein; the micropolarity for albumin is lower than those for α- and γ-globulins.     

Flow injection—atomic absorption spectrometry with organic solvents

A flow injection technique with an organic solvent carrier stream is recommended for the determination of trace elements by atomic absorption spectrometry. Carrier streams of methyl isobutyl ketone and especially n-butyl acetate are effective in enhancing sensitivity. The proposed method permits about 300 determinations per hour with a relative standard deviation of less than 5%.     

Positive muon sites and possibility of anyons in the YBa2Cu3O x system

Possible positive muon sites in YBa₂Cu₃O _x were determined from the observedμ ⁺ hyperfine fields in antiferromagnetically ordered YBa₂Cu₃O _x and GdBa₂Cu₃O₇. After determining theμ ⁺ sites, the possibility of anyons or chiral spin ordering in the superconducting YBa₂Cu₃O₇ is discussed. Positive muon implanted in YBa₂Cu₃O₇ feel static magnetic fields of average 1.4G, which are explicable in terms of nuclear magnetic dipolar fields. Non observation of static local magnetic fields of electronic origin (the upper limit is the order of 0.1 G) means that anyons or chiral spin ordering might not exist in superconducting YBa₂Cu₃O₇.