High-spin states in neutron-rich Dy isotopes populated in deep-inelastic reactions

High-spin states in neutron-rich Dy isotopes, populated in deep-inelastic processes produced by the interaction of 234 MeV ³⁷Cl ions with a ¹⁶⁰Gd target, have been studied using the highly sensitive EUROBALL IV gamma-ray detector array. The previously known level schemes for ^{159,160,161,162}Dy have been extended to significantly higher spin ( ? 30?) and the i _13/2 band crossing in ¹⁵⁹Dy has been observed for the first time. The experimental results are discussed within the framework of cranked shell model and projected shell model calculations with particular reference to the observed delayed band crossing in ¹⁶²Dy. Received: 20 October 2000 / Accepted: 16 January 2001     

ON THE PRODUCT OF GTEAUX DIFFERENTIABILITY LOCALLY CONVEX SPACES

A locally convex space is said to be a Gateaux differentiability space (GDS) provided every continuous convex function defined on a nonempty convex open subset D of the space is densely Gateaux differentiable in .D.This paper shows that the product of a GDS and a family of separable Prechet spaces is a GDS,and that the product of a GDS and an arbitrary locally convex space endowed with the weak topology is a GDS.     

Cis-and Trans-Coordination Assembly of Nitrogen Heterocycle with Copper(II) and Silver(I)

After the preparation of 1,4-bis(4,5-dihydro-1H-imidazol-2-yl)benzene(bdib),a nitrogen heterocycle with potential coordination manners of both cis-and tram-configuration forms,three complexes,including successfully self-assembled.Complexes 1 and 2 crystallized in the monoclinic system with P21/n space group and complex 3 in the triclinic system with P1 space group.     

Crystallization of zinc lactate in presence of malic acid

The influence of malic acid, which acts as an impurity on the cooling crystallization of zinc lactate is investigated in this paper by monitoring the relative supersaturation and the number of crystals during crystallization. The presence of malic acid increases the solution solubility and makes the metastable zone wider; it also changes the habit of the crystal. The purity of the final products is shown to be influenced by the amount and size of seed crystals, cooling rate, seeding temperature and final temperature, but appears to depend mainly on the particle size and level of supersaturation. Residual supersaturation thresholds are observed that depend on the final temperature. A model is proposed to predict the steady-state supersaturation value from the final temperature at a given impurity concentration. This model is based on Kubota and Gibbs equations.     

Improving the properties of HDPE based separators for lithium ion batteries by blending block with copolymer PE-b-PEG

To improve the performances of HDPE-based separators, polyether chains were incorporated into HDPE membranes by blending with poly(ethylene-block-ethylene glycol) (PE-b-PEG) via thermally induced phase separation (TIPS) process. By measuring the composition, morphology, crystallinity, ion conductivity, etc, the influence of PE-b-PEG on structures and properties of the blend separator were investigated. It was found that the incorporated PEG chains yielded higher surface energy for HDPE separator and improved affinity to liquid electrolyte. Thus, the stability of liquid electrolyte trapped in separator was increased while the interfacial resistance between separator and electrode was reduced effectively. The ionic conductivity of liquid electrolyte soaked separator could reach 1.28 × 10-3 S.cm-1 at 25℃, and the electrochemical stability window was up to 4.5 V (versus Li + /Li). These results revealed that blending PE-b-PEG into porous HDPE membranes could efficiently improve the performances of PE separators for lithium batteries.     

Synthesis,Characterization and Self‐Assembly of Novel Amphiphilic Block Copolymers with a Polyhedral Oligomeric Silsesquioxanes Moiety Attached at the Junction of the Two Blocks

A novel well‐defined amphiphilic block copolymer, with the polyhedral oligomeric silsesquioxane (POSS) moiety at the junction of the two blocks of polystyrene and poly(ethylene oxide) (PEO), was designed and synthesized. First, a macroinitiator containing a POSS moiety and a PEO chain was prepared and then atom transfer radical polymerization of styrene was carried out in the presence of the macroinitiator in bulk. The polymerization results show that the process bears the characteristics of controlled/living free radical polymerizations. The structure and molecular weight of the polymers were characterized by GPC, ¹H NMR, and FT‐IR spectroscopy. The self‐assembly behaviors of the polymers was investigated by TEM and SEM. It was observed that the polymers can self‐assemble into vesicles in aqueous solution.

     

甲烷无氧脱氢芳构化双促进W/MCM-22基催化剂研究

以MCM-22分子筛为载体,H₂SO₄酸化的(NH₄)₂WO₄为W组分前驱物,以Zn和/或Ca,Co,Mo为促进剂,研制两系列促进型W/MCM-22基催化剂.在常压固定床连续流动反应器-GC测试系统评价其对CH₄无氧脱氢芳构化的催化性能,结果显示,在双促进的W-Co-Mo(或W-Ga-Zn)/MCM-22催化剂上,常压、1073 K、原料气空速GHSV=1500 mL(STP)·h^-1·(g-cat.)^-1的反应条件下,苯选择性最高达到70%～72%,相应甲烷转化率为～15%;反应450 min后,甲烷转化率降低到～5%水平;7.5 h平均积炭选择性～20%.H₂-TPR和NH₃-TPD表征研究显示,在W/MCM-22基质催化剂中适当添加少量Co^3+/2+/Mon⁺或Ga³⁺/Zn²⁺,一方面导致Wⁿ⁺物种还原活化温度下降及可还原W⁶⁺物种数量增加,另一方面消去最强的一些B酸位同时诱生相当数量的中强酸位,这两方面的促进效应都对催化剂活性、选择性提高及结炭减缓作出贡献.     

7,3′-二甲氧基-4′,5′-次乙二氧基黄烷酮的合成

以香草醛和问苯二酚为原料,经7步反应合成了新的苯并二氧六环新木脂素黄酮类似物7,3′-二甲氧基-4′,5′-次乙二氧基黄烷酮,总收率16．1％,其结构经^1H NMR,IR和MS证实。     

ZrO2添加量对ZTA陶瓷力学性能及冲蚀磨损行为的影响

以α-Al2O3、ZrO(NO3)2.2H2O和氨水为原料,通过高温煅烧制备了ZTA复相陶瓷材料,研究了ZrO2添加量对ZTA陶瓷物相组成、表面微观形貌、力学性能以及常温固体粒子冲蚀磨损性能的影响。结果表明:随着ZrO2添加量增加,材料的力学性能逐渐提高,当ZrO2添加量为10 vol%时,ZTA复相陶瓷抗弯强度和断裂韧性分别达461MPa和5.77 MPa.m1/2,相对于纯Al2O3陶瓷提升量达21.3%和64.9%。ZTA复相陶瓷材料的体积冲蚀率随着ZrO2添加量的增加而降低,当ZrO2添加量小于4 vol%时,其体积磨损率急剧下降,随后趋于平稳;随后当ZrO2添加量为10 vol%时,其冲蚀率达最低,为0.015 mm3/g。其中,纯Al2O3陶瓷材料的冲蚀磨损机制主要为横向裂纹相互交错导致材料的剥落,添加ZrO2后,其冲蚀磨损机制以塑性变形为主。