cis-Dichloridobis(1,10-phenanthroline-kappa N-2,N ')-cadmium(II) hemihydrate

The title compound, [ CdCl2( C12H8N2)(2)]center dot 0.5H(2)O, crystallizes with two independent complex molecules and one water molecule in the asymmetric unit. The Cd atoms in both independent complexes display a distorted octahedral coordination geometry formed by four N atoms from two phenanthroline ligands and two Cl atoms. In the crystal structure, pi-pi stacking interactions link complexes in two symmetry- independent ladders parallel to the c axis. Intermolecular O-H center dot center dot center dot Cl hydrogen bonds stabilize the crystal packing.

Synthesis and structure of new low dimensional polymeric haloplumbate(II) complexes [Pb4Br12(C40H40N8)] and [Pb4Cl12(C40H40N8)]center dot H2O

New low dimensional polymeric haloplumbate(II) complexes of the dication of (4,4'-bis(imidazolyl-ylmethyl)biphenyl) were synthesised and their crystal structures determined. Complex 1, [Pb4Br12(C40H40N8)], has cis-edge-shared, octahedral, lead bromide double chains. In compound 2 [Pb4Cl12(C40H40N8)]center dot H2O, the inorganic chains are corner-shared, square pyramidal chains of lead chloride. In both compounds the organic ammoniums form regular layers that alternate with the inorganic chains.

Enantioselective Iodolactonizations of 4-Pentenoic Acid Derivatives Mediated by Chiral Salen-Co(II) Complex

This work presents the salen-Co(II) complex catalyzed enantioselective iodolactonizations of various 4-pentenoic acid derivatives with good enantioselectivities (up to 83% ee).

Metal dependent control of cis-/trans-1,4 regioselectivity in 1,3-butadiene polymerization catalyzed by transition metal complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine

Fe(III), Cr(III), Fe(II), Co(II) and Ni(II) chloride complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine have been synthesized and characterized along with single crystal X-ray diffraction. These complexes, in combination with MAO, have been examined in butadiene polymerization. The catalytic activity and regioselectivity are strongly controlled by metal center and cocatalyst (MAO/Co ratio dependent in the case of Co(II) complex). The activity decreases in the order of Fe(III) > Co(II) > Cr(III) approximate to Ni (II) complexes, in consistent with the space around the metal center. Polybutadiene with different microstructure content, from high trans-1,4 units (88-95% for iron(III) and Cr(III)), medium trans-1,4 and cis-1,4 units (55% and 35%, respectively, for iron(II)) to high cis-1,4 units 79% for Co(II) and 97% for Ni(II) call be easily achieved by varying of the metal center.

Synthesis, 2D NMR, electrochemistry and luminescence of ruthenium(II) complexes with 2,2 '-bipyridine and 5-(omega-bromoalkylamido)-1,10-phenanthroline

The efficient synthesis of 5-(5-bromovaleramido)-1,10-phenanthroline, 5-(6-bromohexanamido)-1,10-phenanthroline, and 5-(11-bromoundecanamido)-1,10-phenanthroline are described, which reacted with cis-Ru(bpy)(2)Cl-2. 2H(2)O and sodium hexafluorophosphate to form Ru(bpy)(2)[phen-NHCO(CH2)(n)Br](PF6)(2) (n = 4, 5 or 10; phen = 1,10-phenanthroline). The intricate H-1 NMR spectra at low field of these complexes were completely assigned in virtue of H-1-H-1 COSY technique. Cyclic voltammetry was used to study electrochemical behaviours of these complexes, and their luminescent properties were investigated with fluorescent spectra.

Energy conversion in shape memory alloy heat engine - Part II: Simulation

In this paper, a theoretical model proposed in Part I (Zhu et al., 2001a) is used to simulate the behavior of a twin crank NiTi SMA spring based heat engine, which has been experimentally studied by Iwanaga et al. (1988). The simulation results are compared favorably with the measurements. It is found that (1) output torque and heat efficiency decrease as rotation speed increase; (2) both output torque and output power increase with the increase of hot water temperature; (3) at high rotation speed, higher water temperature improves the heat efficiency. On the contrary, at low rotation speed, lower water temperature is more efficient; (4) the effects of initial spring length may not be monotonic as reported. According to the simulation, output torque, output power and heat efficiency increase with the decrease of spring length only in the low rotation speed case. At high rotation speed, the result might be on the contrary.

铁基抗高温磨损激光熔覆涂层强韧设计和研究II:Fe-Cr-C-W-Ni激光熔覆层的微观组织及性能

本文以对热工模具进行失效分析的基础上，利用激光熔覆技术，在５ＣｒＭｎＭｏ基础上设计并制备强韧兼备的抗高温磨损涂层。

Studies on the phase diagram of the surfactant/1-pentanol water ternary system II: The liquid crystalline phase

The phase behavior of liquid crystalline in the ternary system of dodecyl dimethyl ammonium hydroxyl propyl sulfonate(DDAHPS)/1-pentanol(C5H11OH)/water deuteron (D2O) has been investigated by polarizing optical microscopy, H-2 NMR spectroscopy methods. The results indicate that two kinds of liquid crystals (the lamellar, and the hexagonal) exist in the liquid crystalline phase region. In this paper, we also use the polarized Raman spectroscopy method to measure the values of the order/disorder parameters and the values of the environment polarity parameters for the samples selected from the liquid crystalline phase region, and compare these two parameters of the samples with those of solid state DDAHPS and liquid state pentan-1-ol.

Mode I and Mode II Crack Tip Asymptotic Fields with Strain Gradient Effects

The strain gradient effect becomes significant when the size of fracture process zone around a crack tip is comparable to the intrinsic material length l, typically of the order of microns. Using the new strain gradient deformation theory given by Chen and Wang, the asymptotic fields near a crack tip in an elastic-plastic material with strain gradient effects are investigated. It is established that the dominant strain field is irrotational. For mode I plane stress crack tip asymptotic field, the stress asymptotic field and the couple stress asymptotic field can not exist simultaneously. In the stress dominated asymptotic field, the angular distributions of stresses are consistent with the classical plane stress HRR field; In the couple stress dominated asymptotic field, the angular distributions of couple stresses are consistent with that obtained by Huang et al. For mode II plane stress and plane strain crack tip asymptotic fields, only the stress-dominated asymptotic fields exist. The couple stress asymptotic field is less singular than the stress asymptotic fields. The stress asymptotic fields are the same as mode II plane stress and plane strain HRR fields, respectively. The increase in stresses is not observed in strain gradient plasticity for mode I and mode II, because the present theory is based only on the rotational gradient of deformation and the crack tip asymptotic fields are irrotational and dominated by the stretching gradient.

Teracluster LSSC-II - Its Designing Principles and Applications in Large Scale Numerical Simulations

The teracluster LSSC-II installed at the State Key Laboratory of Scientific and Engineering Computing, Chinese Academy of Sciences is one of the most powerful PC clusters in China. It has a peek performance of 2Tflops. With a Linpack performance of 1.04Tflops, it is ranked at the 43rd place in the 20th TOP500 List (November 2002), 51st place in the 21st TOP500 List (June 2003), and the 82nd place in the 22nd TOP500 List (November 2003) with a new Linpack performance of 1.3Tflops. In this paper, we present some design principles of this cluster, as well as its applications in some largescale numerical simulations.

自适应光学对大气扰动波前的补偿效果研究：II.水平大气传输时…

讨论了光波在水平大气湍流中传输时的情况。计算结果表明自适应光学系统的补偿效果与光波传播路径上的横向风有很大的关系。大气湍流的强度越大, 自适应光学系统的截止频率越高, 横向风的影响也越大。计算结果还表明在相同的r0 或者相同的大气湍流强度下, 球面波所受大气扰动的自适应光学补偿效果受横向风的影响要比平面波的厉害。本文还将理论分析的结果和数值模拟的结果进行了比较, 表明数值模拟结果受横向风的影响比理论分析结果受横向风的影响大。最后, 文中分析了以上现象并对此作出了合理的解释。

Electron Beam Surface Treatment. Part II: Microstructure Evolution of Stainless Steel and Aluminum Alloy During Electron Beam Rapid Solidification

Surface rapid solidification microstructures of AISI 321 austenitic stainless steel and 2024 aluminum alloy have been investigated by electron beam remelting process and optical microscopy observation. It is indicated that the morphologies of the melted layer of both stainless steel and aluminum alloy change dramatically compared to the original materials. Also, the microstructures were greatly refined after the electron beam irradiation.

Investigation Of Mode Ii Crack Growth Following A Very High Speed Impact

A recoverable plate impact testing technology has been developed for studying fracture mechanisms of mode II crack. With this technology, a single duration stress pulse with submicrosecond duration and high loading rates, up to 10(8) MPam(1/2)s(-1), can be produced. Dynamic failure tests of Hard-C 60# steel were carried out under asymmetrical impacting conditions with short stress-pulse loading. Experimental results show that the nucleation and growth of several microcracks ahead of the crack tip, and the interactions between them, induce unsteady crack growth. Failure mode transitions during crack growth, both from mode I crack to mode II and from brittle to ductile fracture, were observed. Based on experimental observations, a discontinuous crack growth model was established. Analysis of the crack growth mechanisms using our model shows that the shear crack extension is unsteady when the extending speed is between the Rayleigh wave speed c(R) and the shear wave speed c(S). However, when the crack advancing speed is beyond c(S), the crack grows at a steady intersonic speed approaching root 2c(S). It also shows that the transient mechanisms, such as nucleation, growth, interaction and coalescence among microcracks, make the main crack speed jump from subsonic to intersonic and the steady growth of all the subcracks causes the main crack to grow at a stable intersonic speed.