Superferromagnetic state of α-Fe in Fe implanted Co6Ag94 studied by Mössbauer spectroscopy

After having introduced by ion implantation ⁵⁷Fe to a local concentration of 7 at% into Co₆Ag₉₄, we observed it by conversion electron Mössbauer spectroscopy in the as-prepared state and after isochronal annealing. A superferromagnetic state is inferred, which is correlated with the ordering of the magnetic moments on the Fe clusters through chain-like or dendritic Co/Fe linear structures. The magnetic moment disordering temperature lies above 473 K.     

单件小批生产系统下模糊优化的动态随机投入产出模型

本文针对单件小批量生产系统 ,建立了模糊优化的动态随机投入产出模型 ,同时给出了该模型的递推解法 ,并用此模型对某单件小批企业在生产计划期的商品量进行了规划     

Quantum Thermal Effect of Dirac Particles in a Nonuniformly Rectilinearly Accelerating Black Hole with Electric Charge, Magnetic Charge, and Cosmological Constant

The Hawking radiation of Dirac particles in an arbitrarily rectilinearly accelerating Kinnersley black hole with electromagnetic charge and cosmological constant is investigated by using the generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the time and the polar angle. The Hawking thermal radiation spectrum of Dirac particles is also derived.     

房水中烯醇化酶总活性的联酶荧光法测定

采用酶联反应荧光法测定样品中烯醇化酶的总活性。方法最低检出限为０２ＩＵ／Ｌ，在０２０～３５ＩＵ／Ｌ范围标准曲线呈线性，γ＞０９９７，回收率达９０％，相对标准偏差＜１０％。对临床确诊的视网膜母细胞瘤进行了初步探讨，检验结果的特异性较高。     

ESTIMATE ON LOWER BOUND OF THE FIRST EIGENVALUE OF A COMPACT RIEMANNIAN MANIFOLD

The author gives an optimum estimate of the first eigenvalue of a compact Riemannian manifold. It is shown that let M be a compact Riemannian manifold, then the first eigenvalue λ_1 of the Laplace operator of M satisfies α_1+max{0,-(n-1)K}≥π~2/d~2 where d is the diameter of M and (n-1)K is the negative lower bound of the Ricci curvature of M.     

Trefftz,collocation, and other boundary methods—A comparison

In this article we survey the Trefftz method (TM), the collocation method (CM), and the collocation Trefftz method (CTM). We also review the coupling techniques for the interzonal conditions, which include the indirect Trefftz method, the original Trefftz method, the penalty plus hybrid Trefftz method, and the direct Trefftz method. Other boundary methods are also briefly described. Key issues in these algorithms, including the error analysis, are addressed. New numerical results are reported. Comparisons among TMs and other numerical methods are made. It is concluded that the CTM is the simplest algorithm and provides the most accurate solution with the best numerical stability. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007     

Poly(phenylene vinylene)‐based copolymers containing 3,7‐phenothiazylene and 2,6‐pyridylene chromophores: Fluorescence sensors for acids,metal ions,and oxidation

A novel copolymer, poly(N‐hexyl‐3,7‐phenothiazylene‐1,2‐ethenylene‐2,6‐pyridylene‐1,2‐ethenylene) ( P3 ), containing N‐hexyl‐3,7‐phenothiazylene and 2,6‐pyridylene chromophores was synthesized to investigate the effect of protonation, metal complexation, and chemical oxidation on its absorption and photoluminescence (PL). Poly(N‐hexyl‐3,8‐iminodibenzyl‐1,2‐ethenylene‐1,3‐phenylene‐1,2‐ethenylene) and poly(N‐hexyl‐3,7‐phenothiazylene‐1,2‐ethenylene‐1,3‐phenylene‐1,2‐ethenylene) ( P2 ), consisting of 1,3‐divinylbenzene alternated with N‐hexyl‐3,8‐iminodibenzyl and N‐hexyl‐3,7‐phenothiazylene, respectively, were also prepared for comparison. Electrochemical investigations revealed that P3 exhibited lower band gaps (2.34 eV) due to alternating donor and acceptor conjugated units (push–pull structure). The absorption and PL spectral variations of P3 were easily manipulated by protonation, metal chelation, and chemical oxidation. P3 displayed significant bathochromic shifts when protonated with trifluoroacetic acid in chloroform. The complexation of P3 with Fe³⁺ led to a significant absorption change and fluorescence quenching, and this implied the coordination of ferric ions with the 2,6‐pyridylene groups in the backbone. Moreover, both phenothiazylene‐containing P2 and P3 showed conspicuous PL quenching with a slight redshift when oxidized with NOBF₄. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1272–1284, 2004     

热等离子体裂解天然气制备C2烃

采用氮气热等离子体来裂解天然气制备乙炔乙烯,着重研究了天然气转化率和乙炔、乙烯收率随氮气流量和天然气流量的变化.结果表明,天然气流量与氮气流量之比为11时,可得到较好的结果.当等离子体功率为15kW、天然气流量为3Nm3*h-1、氮气流量为3Nm3*h-1时得到最好的结果.这时天然气转化率为57%,乙炔、乙烯的收率分别为34%和9%;乙炔在反应气中的体积浓度为7.5%,与部分氧化法相似;扣除不参加反应的氮气,乙炔在气相产品中的体积浓度为13.2%,与热力学平衡计算结果基本符合.     

An eulerian trail traversing specified edges in given order

The following results are proved in this paper. Let G be a 2k-edge-connected eulerian graph. (i) For every set {e₁, e₂, ?, e_2k+1} ? E(G) there is an eulerian trail T of the form e₁, e₂, ?, e_2k+1, ?. (ii) For every set E* = {e₁, e₂, ?, e_k} ? E(G) there is an eulerian trail T = e₁, ?, e₂, ?, e_k, ? in which the elements of E* are traversed in accordance with a prescribed orientation. © 1995 John Wiley & Sons, Inc.