Real meromorphic functions and linear differential polynomials

We determine all real meromorphic functions f in the plane such that f has finitely many zeros, the poles of f have bounded multiplicities, and f and F have finitely many non-real zeros, where F is a linear differential polynomial given by F = f (k) +Σk-1j=0ajf(j) , in which k≥2 and the coefficients aj are real numbers with a0≠0.     

Parameter Estimation for Observed Diffusions in Manifolds

Following the procedure described by Elworthy (1982) and Ikeda& Watanabe (1981) we construct the solution of stochasticdifferential equations (SDEs) in manifolds. We take such SDEsto describe parametrized completely observed stochastic systemsand manifold-valued state processes. The likelihood functionfor the system parameter is computed by two methods: the firstapplies to the case of parallelizable manifolds; the secondapplies to the general case, here the solution of the systemSDE is constructed in the orthonormal frame bundle of the manifold.Two examples are given.     

Space Group of Aquaimidazolemaleatozinc, [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n

The space group of [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n, which was originally described in the acentric Pc space group (Liu et al., Chin. J. Struct. Chem. 2004, 23, 160～163), is re-described in the centric P21/c space group.The crystal structure of (H2O)(C3H4N2)O2C-CH=CHCO2Zn was refined in the acentric Pc space group on 266 variables to R = 0.037 for the 1926 of the 2067 obeying the I > 2σ criterion[1]. The structure is better described in the centric P21/c space group (Table 1) as the two indepen-dent formula units are related by a center of symmetry. The 21 screw axis is must be pre-sent, as noted from the systematically absent 0k0 (k = 2n + 1) reflections in the 3302 reflections that were simulated[2, 3] from the published cell dimensions and atomic coordinates. Crystallo-graphica[4] estimates the hemisphere of reflections to be 3302, so that only a little more than the minimum monoclinic data must have been collec-ted in the study. A revision from Pc to P21/c is not particularly common[5] as the P21/c space group is uniquely determined from systematic absences. The polymeric chain propagates linearly along the c-axis of the unit cell (Fig. 1).     

On the Crystal Structure of [Cu(OH)_2(H_2O)_2(4-C_5H_4NCOOH)_2]

In their report of the crystal structure of the compound claimed to be [Cu(OH)2(H2O)2(4- C5H4NCOOH)2], the authors did not give any experimental details on the location and refinement of the water and hydroxyl hydrogen atoms[1]; they had assumed the presence of the carboxylic -CO2H unit on the basis of the infrared stretching frequency at 1700 cm-1 that is only of medium intensity. The cell constants for the compound are, in fact, identical, with those documented for tetraaquabis(isonicot…     

球面上等收敛算子的有界性

设Rⁿ 是n-维欧氏空间n≥3.用Ω_n表示Rⁿ 上的单位球面,对于函数f∈L（Ω_n）,E_N^δ（f）表示其Fourier-Laplace级数的δ阶Cesaro平均所决定的等收敛算子,其中,λ:=（n-2）/2,δ是熟知的临界指标.对于0<δ≤λ,令p₀:=(2λ)/（λ+δ）,本文主要证明了如下结果:     

GS型包合物G2PEDS·MeOH·2(H2O)和G2PEDS·naphthalene的合成与晶体结构

合成了两个由胍盐(G)和4，4’—苯醚二磺酸(PEDS)为主体框架所形成的主— 客体包合物，分别为[(CH6N3)]2[(C12H8O7S2)]·MeOH·2(H20)(1)和[(CH6N3)]2[ (C12H8O7S2)]·(C10H8)(2)．两个化合物都是以P—1空间群结晶，晶胞参数分别为 ：1a＝0．7509(4)nm，b＝1．2113(6)nm，c＝1．5936(8)nm，a＝102．636(10)° ，β＝102．703(11)°,γ＝91．318(10)°；2a＝0．75409(3)nm，b＝1．21584 (5)nm，c＝3．09376(14)nm，a＝81．506(2)°，β＝89．669(2)°，γ＝88． 890(2)°。在这两个晶体结构中，G和PEDS通过氢键形成了双夹层—双柱子的主体 框架，客体分子被包合在平行于a轴方向的晶格空间．这种双夹层—双柱子的主体 框架在由胍盐(G)和有机二磺酸(S)体系所形成的、具有通道结构的主体框架中是较 为少见的．     

用宇宙线大气簇射Ne-Nμ关系研究“膝”区原初成分

用梁王山宇宙线观测站获得的宇宙线大气簇射μ子数据, 与假设原初分别为质子、氦核、中等核(Z=15)和铁核的Monte-Carlo模拟结果进行比较, 结果显示宇宙线膝区原初成分无明显变化且以轻核为主.     

热解压力对生物质焦结构及气化反应性能的影响

利用加压固定床反应器、吸附仪、X射线衍射仪、元素分析仪、电感耦合等离子原子发射光谱仪等考察了热解压力对生物质半焦(以下简称半焦)产率、物化结构、元素组成的影响规律。同时,利用热天平对不同热解压力下所制半焦的气化行为进行了考察。结果表明,随热解压力升高,半焦产率增大,当压力升至1.0 MPa后,半焦产率基本不变;半焦中C元素含量随热解压力的升高而增加,而H元素含量和BET比表面积则减小;此外,随热解压力升高,玉米秸秆焦和锯末焦的石墨化程度增强,而稻壳焦的石墨化程度则基本不受热解压力影响。气化反应的研究表明,玉米秸秆焦及锯末焦的平均气化反应速率随热解压力的提高而减小,而稻壳焦的平均气化反应速率基本不受热解压力的影响。热解压力对半焦BET比表面积及碳微晶结构的影响规律与气化反应速率变化规律的对比研究表明,热解压力引起半焦微晶结构的变化是造成热解压力对半焦气化反应速率影响的主要原因。     

基于6-羟基-2-吡啶基膦酸配体的铜配合物的合成、结构及磁性

在水热条件下, 以6-羟基-2-吡啶基膦酸为主配体, 4, 4′-联吡啶(bpy)及1, 2-二(4-吡啶基)乙烯(bpe)为桥联配体, 合成了2个铜膦酸配位聚合物[Cu₃(L)₂(bpy)₂(H₂O)₂]· 2H₂O (1), [Cu₃(L)₂(bpy)₂(H₂O)₃]· 2H₂O (2)。配合物1中, Cu²⁺离子由膦酸配体连接成一条链, 该链由bpy桥联成二维层, 层与层之间通过氢键作用构成三维结构。配合物2与配合物1是同构的, 桥联配体是bpe。磁性研究表明, 配合物1与2中铜离子之间存在反铁磁性耦合。     

Parallel sparse Gaussian elimination with partial pivoting

In this article, we consider the factorization of a sparse nonsymmetric matrix using Gaussian elimination with partial pivoting on a multiprocessor having a globally-shared memory. The parallel algorithm makes use of a static data structure developed by George, Liu and Ng in [17]. Some numerical experiments on a Sequent Balance 8000 are presented to demonstrate the efficiency of the parallel implementation.Research supported in part by the Applied Mathematical Sciences Research Program, Office of Energy Research, U.S. Department of Energy under contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc.