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61.
The new misfit layer compound (LaSe)1.14(NbSe2)2 has been synthesized from the elements at 1050- and its structure has been determined by a composite approach. The structure has an alternating stacking sequence of [LaSe] and two [NbSe2] layers along the c direction. The misfit of the two different layers is occurring along the a direction: a1(LaSe)=6.0191 Å and a2(NbSe2)=3.4372 Å therefore yielding a ratio of 1.751 which is very close to 7/4. An investigation of electrical resistivity was done. The crystal shows superconducting properties at 5.3 K. 相似文献
62.
Kai Kang Cheng-you Kan Yi Du De-shan Liu 《高分子科学》2005,(5):479-485
Soap-free poly(methyl methacrylate-ethyl acrylate-methacrylic acid) latex particles with narrow size distribution were synthesized by seeded emulsion polymerization, and the porous particles were created by a stepwise alkali/acid treatment method. Effects of acid treatment conditions on the particle morphology were investigated. Results show that one to three pores were formed inside most of particles after post-treatment. At pH 7.0, when the treatment temperature was lower than 70℃, the size of particles and the volume of pores remained almost unchanged, and these two values increased significantly when the temperature was higher than 70℃. Both the particle size and the pore volume decreased with the increase of initial pH value and treatment time in the acid treatment. As the pH was below 4.0 and the treatment time was longer than 180 min, the particles shrunk in size. 相似文献
63.
A new lead(Ⅱ) carboxylate-sulfonate has been hydrothermally synthesized and characterized by X-ray single-crystal and elemental analyses. It crystallizes in triclinic, space group P,(1) with a=8.1573(6), b=9.4663(7), c=12.7488(9) (A), α=89.2320(10), β=80.7380(10), γ=77.9760(10)°, Z=2, V=950.10(12) (A)3, Mr=599.57, Dc=2.096 g/cm3, μ=9.032 mm-1, F(000)=572, the final R=0.0412 and wR=0.1035. It has a 1D chain structure, and the Pb(Ⅱ) is six-coordinated. Two PbO6 polyhedra are interconnected via edge-sharing into a two-core unit. Such units are further interconnected by 3-sulfonato-benzoic acids into 1D chains which are linked by hydrogen bonds into a layer structure. The 4,4'-bipyridines are located at the interlayer space and link the layers into a supramolecular structure by π-π stacking interactions. 相似文献
64.
3-取代-5(3-乙基-4,5-二苯基噻唑叉)洛丹宁的增感性能 总被引:1,自引:0,他引:1
简单份菁(或称零甲川份菁)是一种可以用作卤化银感光乳剂层感蓝增感的染料。彩色正性材料的发展,要求感蓝乳剂层使用氯溴化银乳剂,并配合使用感蓝增感染料以符合感蓝区域的光谱要求。以氩离子激光为光源的电子分色片乳剂要求对波长488nm附近有较高的敏感,此种乳剂本身感色范围偏离氩离子激光发射峰。寻找增感效率高、光谱增感峰适合的感蓝染料很有必要。本文用2-甲硫基-3-乙基-4,5二苯基噻唑对甲苯磺酸盐(1)分别与3-取代洛丹宁(2)在无水乙醇存在下反应,制得六个未见文献报导的3-取代-5-(3-乙基- 相似文献
65.
66.
根据反应层的概念对在任一给定形状微电极上进行的准一级和二级均相催化反应机理(EC'')的稳态电化学行为进行了研究。本方法简便易行,不需要解复杂方程的数学技巧。利用推导出的这些方程,可计算准一级和二级均相催化反应的动力学常数。 相似文献
67.
68.
通过流动相中电解质浓度对毛细管电色谱柱效能的流动相平均线速度的影响,研究了CEC中双电层叠加现象。提出选择合适电解质组成的浓度及在制备色谱柱过程中避免细小和破碎的固定相颗粒进入柱中,以有效地减小双电层叠加作用。 相似文献
69.
70.
Soap-free poly(styrene-ethyl acrylate-acrylic acid) latex particles with narrow size distribution and with surface carboxyl groups were synthesized by semicontinuous emulsion polymerization, and the particles with homogeneous multihollow structure were obtained after alkali posttreatment. Effects of treatment conditions and crosslinking agents on particle morphology were investigated. Results showed that the multihollow structure can be formed inside the uncrosslinked particles only when the treatment temperature exceeded 50 °C, the pH was higher than 10.0, the amount of 2-butanone was more than 3.0 ml and the treatment time was longer than 30 min. Furthermore, the volume expansion of the particles increased with the temperature increased to 90 °C, the pH to 12.5 or the amount of 2-butanone to 7.0 ml, and this value increased first and then decreased with the treatment time prolonged. Fine pores can be generated in the shell of particles crosslinked by 0.2 g of ethyl glycol dimethylacrylate (EGDMA), while no hollow structure formed inside particles when 0.4 g of EGDMA or 0.2 g of divinyl benzene was used. 相似文献