(C5H6N)4[Be6(HPO3)8]·H2O: A low-density open-framework beryllium phosphite with multidirectional 12-ring channels

Employing the common pyridine (=py) solvent as the source of structure-directing agents (SDAs), a novel three-dimensional open-framework beryllium phosphite (Hpy)₄[Be₆(HPO₃)₈]·H₂O (1), has been solvothermally synthesized and structurally characterized by IR, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffractions. It crystallizes in the orthorhombic system, space group Pbca (No. 61), a = 20.0034(4) Å, b = 20.2188(4) Å, c = 20.9731(3) Å, V = 8482.5(3) Å³, and Z = 8. The alternating connection of BeO₄ tetrahedra and HPO₃ pseudopyramids give rise to a (3, 4)-connected network with multidirectional intersecting 12-ring channels. The compound possesses a low density and a new {4.8.10}{4².6.8.10.12}{4².6}₃{4².8.10².12}{4³.6².8} topology.     

Effect of thermal annealing on sub-band-gap absorptance of microstructured silicon in air

The optical absorption properties of femtosecond-laser-made “black silicon” as a function of the annealing conditions were investigated. We found that the annealing process changes the surface morphology and absorption spectroscopy of the “black silicon” samples, and obtained a maximum sub-band-gap absorptance value of approximately 30% by annealing at 1000 °C for 30 min. The thermal relaxation and atomic structural transformation mechanisms are used to describe the lattice recovery and the increase and decrease of the substitutional dopant atom concentration in the microstructured surface during the annealing. Our results confirm that: i) owing to the thermal relaxation, the lattice defects decrease with the increase of the annealing temperature; ii) the quasi-substitutional and interstitial configurations of the doped atoms transform into substitutional arrangements when the annealing temperature increases; iii) the quasi-substitutional and interstitial configurations with higher energies of the doped atoms transform into interstitial configurations with the lowest energy after high-temperature annealing for a long period of time, causing the deactivation or reactivation of the sub-band-gap absorptance by diffusion. The results demonstrate that the annealing can improve the properties of “black silicon”, including defects repairing, carrier lifetime lengthening, and retention of a high absorptive performance.     

Essential extensions and radical classes of lattice-ordered groups

In this paper the relationship between essential extensions and radical classes of lattice-ordered groups is discussed. It is proved that the polar radical classes of lattice-ordered groups are exactly essentially closed classes.Received May 7, 1999; accepted in final form September 23, 2004.     

Standard Bases of a Vector Space Over a Linearly Ordered Incline

Inclines are additively idempotent semirings, in which the partial order ≤ : x ≤ y if and only if x + y = y is defined and products are less than or equal to either factor. Boolean algebra, max-min fuzzy algebra, and distributive lattices are examples of inclines. In this article, standard bases of a finitely generated vector space over a linearly ordered commutative incline are studied. We obtain that if a standard basis exists, then it is unique. In particular, if the incline is solvable or multiplicatively-declined or multiplicatively-idempotent (i.e., a chain semiring), further results are obtained, respectively. For a chain semiring a checkable condition for distinguishing if a basis is standard is given. Based on the condition an algorithm for computing the standard basis is described.     

Synthesis,crystal structure and magnetic properties of a novel manganese(II)-nitronyl nitroxide-azido(μ<Subscript>1,1</Subscript> and μ<Subscript>1,3</Subscript>) one-dimensional complex

A novel one-dimensional manganese(II) complex containing nitronyl nitroxide radical [Mn₂(IM2-py)₂(Ac)₂(μ_1,1-N₃)(μ_1,3-N₃) · EtOH] _n was synthesized and characterized structurally and magnetically. It crystallizes in the monoclinic space group p2₁/n. Each Mn(II) ion is six-coordinated in a distorted octahedral environment. The two N atoms of the nitronyl nitroxide radical and the two O atoms of acetate ligands are in the equatorial plane, whereas the two different azido bridging ligands are in trans axial position. Mn(II) ions are linked by nitrogen atom of μ_1,1-azido and oxygen atoms of two carboxy groups to form a Mn-Mn unit. Mn-Mn units are linked by azido ligands through μ_1,3 bridging style to form a one-dimensional chain. The compound is connected by the coordination bonds, π-π interactions and hydrogen bonds as a three-dimensional structure. Magnetic susceptibility data support that there are stronger antiferromagnetic interactions between the radical and Mn(II) ion, weak antiferromagnetic interactions between the Mn-R units, and very weak antiferromagnetic interactions between the R-Mn-Mn-R units.     

2-取代-3-芳基-4-噻唑啉(硫)酮衍生物的合成、晶体结构和生物活性

从2-取代-3-芳基-4-噻唑啉酮(4a～4e和5)合成了三个系列新型噻唑啉酮衍生物, 即5-芳基亚甲基-4-噻唑啉酮(6a～6j), 4-噻唑硫酮(7a～7e和8)和4-氰基亚胺基噻唑烷(11a～11e和12). 中间体4a～4e和5由醛、胺和巯基乙酸缩合得到. 所有化合物的结构均经元素分析和¹H NMR确证, 并且采用X射线单晶衍射分析方法测定了化合物4b的结构. 初步生物活性试验结果表明, 部分标题化合物具有一定的杀菌活性和促进黄瓜子叶生根活性.     

Synthesis, crystal structure and magnetic properties of a novel manganese(II)-nitronyl nitroxide-azido(μ_(1,1) and μ_(1,3)) one-dimensional complex

A novel one-dimensional manganese(Ⅱ) complex containing nitronyl nitroxide radical [Mn2(IM2-py)2(Ac)2((μ1.1-N3)(μ1,3-N3) . EtOH]n was synthesized and characterized structurally and magnetically. It crystallizes in the monoclinic space group p21/n. Each Mn(Ⅱ) ion is six-coordinated in a distorted octahedral environment. The two N atoms of the nitronyl nitroxide radical and the two O atoms of acetate ligands are in the equatorial plane, whereas the two different azido bridging ligands are in trans axial position. Mn(Ⅱ) ions are linked by nitrogen atom of μ1,1-azido and oxygen atoms of two carboxy groups to form a Mn-Mn unit. Mn-Mn units are linked by azido ligands through u1,3 bridging style to form a one-dimensional chain. The compound is connected by the coordination bonds,π-π interactions and hydrogen bonds as a three-dimensional structure. Magnetic susceptibility data support that there are stronger antiferromagnetic interactions between the radical and Mn(Ⅱ) ion, weak antiferromagnetic inter     

聚合物假冠醚研究（Ⅰ）单体乙二醇二苯醚的合成与表征

本文以乙二醇为底物,通过中间体乙二醇二苯磺酸酯,合成出了乙二醇二苯醚。对两合成产物进行了红外光谱、薄层色谱。溶解性能及结晶分析,实验结果表明,在乙二醇二苯磺酸酯的合成中,因为使用苯磺酰氯代替了传统的对甲苯磺酰氯磺酰化试剂,并用氯仿做稀释剂以控制催化剂吡啶的恰当使用量,使合成不但经济而且获得82．5％,的较高收率,在乙二醇二苯醚的合成中,采用回流,蒸馏交替使用的实验方法,同时用馏出物沸点数值监控和及时排除体系的水份,使产率达到78．0％。     

结构动力分析的时域配点DQ半解析法

直接从控制微分方程出发,以梁为对象提出了本计算方法。该方法在空间域采用DQ法(DiferentialQuadratureMethod),在时间域取级数,采用时域配点的方式得到求位移场全部待定参数的可解方程组,求解一次线性方程组即可求得全域的响应位移场。     

CeO_2缓冲层热处理对Tl-2212薄膜超导特性的影响

本文采用原子力显微镜(AFM)和XRD研究了生长在蓝宝石(11-02)基片上的CeO_2缓冲层在不同的退火温度和退火时间下表面形貌和相结构的变化,以及对Tl-2212薄膜超导特性的影响.AFM和XRD研究表明,CeO_2薄膜在流动氧环境中退火,表面形貌发生显著的变化;CeO_2薄膜在最佳条件下退火后,可获得原子级光滑表面,结晶质量明显提高.实验结果表明,缓冲层的结晶质量和表面粗糙度与Tl-2212薄膜的超导特性密切相关.在经过最佳条件退火后的CeO_2缓冲层上制备了厚度为500 nm无裂纹的Tl-2212超导薄膜,其临界转变温度(T_c)达到107 K,液氮温度下临界电流密度(J_c)为3.9 MA/cm~2(77 K,0 T),微波表面电阻(R_s)约为281 μΩ(77 K,10 GHz).