A 3 kW average power tunable TEA CO2 laser

A high average power line-tunable TEA CO₂ laser is described. Average output power up to 3 kW is achieved at repetition rate of 180 Hz. The maximum output power is almost equal among the four spectrum bands of CO₂ laser (the P and R branches of 00°1–10°0 and 00°1–02°0 transition bands). Several special technologies including rotating spark gap switching, PCB (printed circuit board) preionization and zeroth-order grating coupling are employed.     

Nigricanin,the First Ellagic Acid Derived Metabolite from the Basidiomycete Russula nigricans

Nigricanin ( 1 ), the first ellagic acid related derivative from higher fungi, has been isolated from the fruiting bodies of the Basidiomycetes Russula nigricans. The structure of the novel compound was established by spectroscopic and chemical methods.     

Nonlinear viscoelastic behavior of styrene‐[ethylene‐(ethylene‐propylene)]‐styrene block copolymer

Studies on the nonlinear viscoelastic behavior of styrene‐[ethylene‐(ethylene‐propylene)]‐styrene block copolymer (SEEPS) were carried out. The nonlinear viscoelastic region was determined through dynamic strain sweep test, and the critical shear strain (γ_c) of transition from linear viscoelastic region to nonlinear viscoealstic region was obtained. The relaxation time and modulus corresponding to the characteristic relaxation modes were also acquired through simulating the linear relaxation modulus curves using Maxwell model, and the damping functions were evaluated. Meanwhile, it is found that the nonlinear relaxation modulus obtained at relatively low shear strains follows the strain–time separation principle, and the damping function of SEEPS can be fit to Laun double exponential model well. Moreover, the successive start‐up of shear behavior, the steady shear behavior, and the relaxation behavior after steady shear were investigated, respectively. The results showed that Wagner model, derived from the K‐BKZ (Kearsley‐Bernstein, Kearsley, Zapas) constitutive equation, could simulate the experiment data well, and in addition, experiment data under the lower shear rates are almost identical with the fitting data, but there exists some deviation for data under considerable high shear rates. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1309–1319, 2006     

怀柔EAS阵列的Monte Carlo研究

用GENAS程序包为怀柔阵列产生了36万Monte Carlo模拟EAS事例,用它们研究了怀柔阵列的性能,确定了最佳的事例判造条件,对实验数据进行了正确性检验,得到了怀柔EAS Size(即簇射在观测面的总荷电粒子数)与初级宇宙线能量之间的转换关系.这项研究表明,怀柔阵列的EAS心位和方向测定精度分别好于3m和2.5°;EASSize测定误差典型值约8%;近垂直簇射的Size(N)与初能(E)的关系为E≈10^10.64N^0.84.     

制作多焦点全息透镜的新方法

本文提出了一种制作多焦点全息透镜的新光路,消除了干板上的多余条纹,从而有效地抑制了杂散光,并导出了用此光路制作的平面型全息透镜的衍射效率,给出了实验结果。     

红外介质波导的参数测量

建立在模方程近似解的基础上,考虑LiNbO₃材料的色散特性,提出了一种用可见激光测量红外介质波导主要参数的方法,给出了实验测量结果,并对结果进行了分析讨论,本文提出的方法方便而且可靠,特别是较好地解决了单模波导的参数测量问题,具有较大的实用意义。     

On the Existence of Solutions of Quasi-equilibrium Problems with Constraints

The quasi-equilibrium problems with constraints are formulated and some sufficient conditions on the existence of their solutions are shown. As special cases, we obtain several results on the existence of solutions of some vector quasivariational inequality and vector optimization problems. An application of the obtained results is given to show the existence of solutions of quasi-optimization problems with constraints.     

Biodegradable brushlike graft polymers. I. Polymerization of ϵ‐caprolactone onto water‐soluble hydroxypropyl cellulose as the backbone by the protection of the trimethylsilyl group

After the protection of partial hydroxyl groups with trimethylsilyl (TMS) groups, hydroxypropyl cellulose becomes soluble in organic solvents, and the number of hydroxyl groups as initiating groups can be controlled. As a result, a new brushlike graft poly(?‐caprolactone) can be prepared with hydroxypropyl cellulose as the backbone polymer by homogeneous ring‐opening graft polymerization and deprotection. The protection and deprotection of the TMS group during the entire procedure were carefully monitored with Fourier transform infrared (FTIR) and NMR, and the final graft copolymers were characterized with FTIR, ¹H NMR, ¹³C NMR, gel permeation chromatography, and differential scanning calorimetry. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 273–280, 2003     

Epoxy/amine‐functionalized short‐length vapor‐grown carbon nanofiber composites

Short length vapor‐grown carbon nanofibers (VGCNFs) were functionalized with 4‐aminobenzoic acid in polyphosphoric acid/phosphorous phentoxide medium via “direct” Friedel‐Crafts acylation reaction to afford aminobenzoyl‐functionalized VGCNFs (AF‐VGCNFs). The AF‐VGCNFs as a cocuring agent were mixed with epoxy resin by simple mechanical stirring in methanol which was added to help efficient mixing. After evaporation of methanol, 4,4′‐methylenedianiline as a curing agent was added to the mixture, which was then cured at elevated temperatures. The resultant composites displayed uniform dispersion of AF‐VGCNFs into cured epoxy matrix. During curing process, the amine functionalities on AF‐VGCNF together with 4,4′‐methylenedianiline were expected to be involved in covalent attachment to the epoxy resin. As a result, both tensile modulus and strength of the composites were improved when compared with those of pure epoxy resin. Thus, the AF‐VGCNFs play a role as an outstanding functional additive, which could resolve both dispersion and interfacial adhesion issues at the same time by functionalization of VGCNFs and covalent bonding between the additive and matrix, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7473–7482, 2008