聚丙烯孔洞铁电驻极体膜的电极化及其电荷动态特性

根据栅控恒压电晕充电组合反极性电晕补偿充电法的实验结果计算出铁电驻极体的极化强度.结果说明，伴随着薄膜内孔洞气体的Paschen击穿，该铁电体的极化强度随栅压增加而显著上升.利用上述充电方法和热刺激放电(TSD)谱的分析讨论了这类空间电荷型宏观电偶极子，及与其补偿的空间电荷热退极化的电荷动态特性；阐明了这两类俘获电荷的能阱分布，即构成宏观电偶极子的位于孔洞上下介质层内的等值异号空间电荷分别被俘获在深、浅两种能值陷阱内，而位于薄膜表面层的注入空间电荷则被俘获在中等能值陷阱中. 关键词： 反极性电晕补偿充电法 铁电驻极体 充电电流 热刺激放电     

SiOx纳米管的制备及其发光特性

以液态金属镓为媒介,利用热蒸发法合成大量非晶SiOx纳米管,这些纳米管管径均匀分布,平均约80 nm,长度大于10μm,且管内外径比例较小．分析发现,在实验过程中,熔入金属镓液滴中的硅元素和氧元素结合并从液滴的表面饱和析出,形成以镓为中心的非晶SiOx纳米管状结构．在室温中,利用260 nm的激发光源激发SiOx纳米管,发现在蓝光波段附近发出强而稳定的PL谱线,这可能与样品中的氧缺陷和空位有关．     

Growth studies of m-GaN layers on LiAlO2 by MOCVD

This paper reports that the m-plane GaN layer is grown on （200）-plane LiAlO2 substrate by metal-organic chemical wpour deposition （MOCVD） method. Tetragonal-shaped crystallites appear at the smooth surface. Raman measurement illuminates the compressive stress in the layer which is released with increasing the layer＇s thickness. The high transmittance （80%）, sharp band edge and excitonic absorption peak show that the GaN layer has good optical quality. The donor acceptor pair emission peak located at -3.41 eV with full-width at half maximum of 120 meV and no yellow peaks in the photoluminescence spectra partially show that no Li incorporated into GaN layer from the LiAlO2 substrate.     

High-throughput screening of fuel cell electrocatalysts

The drawbacks of our earlier report of preparing fuel cell catalyst arrays by borohydride reduction of inkjet prepared arrays of metal salts are discussed along with the need for inclusion of state-of-the-art metrics in all array screening. An alternative method for screening of hydrogen/air cathode catalysts, direct methanol fuel cell (DMFC) anode catalysts, and catalyst loading studies is provided. State-of-the-art Johnson Matthey catalysts were used in control experiments to demonstrate the utility of the array fuel cell for high throughput screening of fuel cell catalysts in the 3-4 mg/cm² range. This report lays out hard learned rules for high throughput screening and demonstrates that the array fuel cell can be used for very precise screening of libraries of membrane electrode assembly (MEA) components without the pitfalls discussed in the introduction.     

Nuclear Quadrupole Coupling Constants of Chlorine and Microwave Spectrum, Structure, and ab Initio Calculation of 1-Chloro-1,1,2-trifluoroethane

The microwave spectrum of the ³⁵Cl and ³⁷Cl isotopic species of 1-chloro-1,1,2-trifluoroethane (HCFC-133b) has been investigated in the frequency region 10 to 50 GHz using a Stark modulation microwave spectrometer. A pulsed jet Fourier transform microwave spectrometer was also used for the measurement of hyperfine splittings. A least-squares analysis of the observed b-type Q- and R-branch transition frequencies gave rotational and centrifugal distortion constants and components of the chlorine nuclear quadrupole coupling constant tensors in the principal axes system as follows: A=4625.161 (3) MHz, B=2004.127 (2) MHz, C=1875.813 (2) MHz, Δ_J=0.144 (9) kHz, Δ_JK=1.0748 (8) kHz, Δ_K=1.57 (1) kHz, δ_J=0.01376 (4) kHz, δ_K=−0.146 (4) kHz, χ_aa=−57.958 (10) MHz, χ_bb=21.231 (11) MHz, and χ_cc=36.727 (11) MHz for ³⁵ClCF₂CH₂F species, and A=4607.684 (6) MHz, B=1960.565 (2) MHz, C=1834.823 (2) MHz, Δ_J=0.106 (7) kHz, Δ_JK=1.022 (3) kHz, Δ_K=1.48 (1) kHz, δ_J=0.0142 (2) kHz, δ_K=−0.18 (2) kHz, χ_aa=−46.268 (11) MHz, χ_bb=17.319 (13) MHz, and χ_cc=28.950 (13) MHz for ³⁷ClCF₂CH₂F species. The structural parameters are calculated from the observed six rotational constants by assuming the partial structure of ab initio calculation. The electronic properties of the C-Cl bond are evaluated from the observed nuclear quadrupole constants of chlorine. These molecular properties are compared with those of other related molecules.     

不连续不可逆二维映象的动力学特性

总结两个保守映象不可逆地分段连续链接(称为类耗散系统)以及一个保守映象与一个耗散映象不可逆地分段连续链接(称为半耗散系统)情况下得到的五项共同动力学特征：不连续边界象集构成的随机网成为唯一的混沌轨道；由于某些相点具有两个逆象而导致的相空间塌缩(类耗散)；由于系统的不连续不可逆性质而出现的胖分形禁区网；在具有吸引子共存时占据不连续边界象集随机网和胖分形禁区网区域的点滴状吸引域以及由此导致的吸引子不可预言性；即使在传统强耗散存在的情况下点滴状吸引域仍由类耗散机制主宰.以一个累积-触发电路为例，说明这五项系统动 关键词： 随机网 禁区网 点滴状吸引域     

双纠缠原子在耗散腔场中的纠缠动力学

研究了能量损耗腔中,两纠缠二能级原子与单模辐射场相互作用过程中原子的纠缠动力学.结果表明:双纠缠原子的纠缠度演化特性决定于初始两原子间的纠缠度、纠缠形式、腔场的平均光数、腔场的衰变系数.当原子初始处于一特定纠缠态时,其纠缠度可以放大,并且不受腔场损耗的影响. 关键词： 二能级原子 纠缠度 密度算符 单模辐射场     

宽带膜厚实时监控过程中膜层折射率的确定方法

为了准确计算出镀膜过程中每层膜的折射率，介绍了实时监控过程中确定膜层折射率的2种方法：一种是由实测的透射比光谱直接反算出膜层的折射率；另一种是用最小二乘法的优化算法实时拟合折射率。试验结果表明：在线反算适合单点监控，所得折射率误差小于2%。然而在实际镀膜过程中,由于宽带内膜层参数误差较大,一般大于25%。为此，采用最小二乘法拟合，即在整个宽光谱范围内采集每个波长点的信息，所得结果误差很小，一般都在2％～5%之间,有时可达到10%,在很大程度上提高了实际镀膜时膜厚监控的精度。     

Assisted Cloning and Orthogonal Complementing of an Arbitrary Unknown Two-Qubit Entangled State

Based on A.K. Pati‘s original idea [Phys. Rev. A 61 (2000) 022308] on single-qubit-state-assisted clone, very recently Zhan has proposed two assisted quantum cloning protocols of a special class of unknown two-qubit entangled states [Phys. Lett. A 336 (2005) 317]. In this paper we further generalize Zhan‘s protocols such that an arbitrary unknown two-qubit entangled state can be treated.     

On completely irreducible operators

Let T be a bounded linear operator on Hilbert space H, M an invariant subspace of T. If there exists another invariant subspace N of T such that H = M + N and M ∩ N = 0, then M is said to be a completely reduced subspace of T. If T has a nontrivial completely reduced subspace, then T is said to be completely reducible; otherwise T is said to be completely irreducible. In the present paper we briefly sum up works on completely irreducible operators that have been done by the Functional Analysis Seminar of Jilin University in the past ten years and more. The paper contains four sections. In section 1 the background of completely irreducible operators is given in detail. Section 2 shows which operator in some well-known classes of operators, for example, weighted shifts, Toeplitz operators, etc., is completely irreducible. In section 3 it is proved that every bounded linear operator on the Hilbert space can be approximated by the finite direct sum of completely irreducible operators. It is clear that a completely irreducible operator is a rather suitable analogue of Jordan blocks in L(H), the set of all bounded linear operators on Hilbert space H. In section 4 several questions concerning completely irreducible operators are discussed and it is shown that some properties of completely irreducible operators are different from properties of unicellular operators. __________ Translated from Acta Sci. Nat. Univ. Jilin, 1992, (4): 20–29