Structure and hardness of a-C:H films prepared by middle frequency plasma chemical vapor deposition

a-C:H films were prepared by middle frequency plasma chemical vapor deposition (MF-PCVD) on silicon substrates from two hydrocarbon source gases, CH₄ and a mixture of C₂H₂ + H₂, at varying bias voltage amplitudes. Raman spectroscopy shows that the structure of the a-C:H films deposited from these two precursors is different. For the films deposited from CH₄, the G peak position around 1520 cm⁻¹ and the small intensity ratio of D peak to G peak (I(D)/I(G)) indicate that the C-C sp³ fraction in this film is about 20 at.%. These films are diamond-like a-C:H films. For the films deposited from C₂H₂ + H₂, the Raman results indicate that their structure is close to graphite-like amorphous carbon. The hardness and elastic modulus of the films deposited from CH₄ increase with increasing bias voltage, while a decrease of hardness and elastic modulus of the films deposited from a mixture of C₂H₂ + H₂ with increasing bias voltage is observed.     

Raman spectra of soda-lime-silicate glass doped with rare earth

Soda-lime-silicate glasses doped with different rare earth oxides (La₂O₃, CeO₂, Nd₂O₃, Gd₂O₃ and Y₂O₃) of 1 mol% content were prepared by the traditional melting-quenching methods. In order to reveal the effects of rare earth elements on the behavior of soda-lime-silicate glass the structures of soda-lime-silicate glasses doped with different rare earth oxides were determined using an INVIA confocal microRaman spectrometer equipped with a CCD detector, and viscosities of glass melts were measured using a rotating crucible viscometer; the melting temperature of the studied glasses was derived on the basis of the Arrhenius equation. Three expressions of the fraction of non-bridging oxygen (NBO/NBO+BO), average number of non-bridging oxygen (NBO) per tetrahedron (NBO/tetrahedron) and average number of bridging corners per tetrahedron (bridges/tetrahedron) for investigated soda-lime-silicate glasses were given, and the effect of rare earth dopants on the structure of soda-lime-silicate was characterized by the Raman shift, variation of the [SiO₄] tetrahedron structural unit Qⁿ (n=1,2,3,4), fraction of non-bridging oxygen and the average number of bridging corners per tetrahedron. The effect of doping rare earth oxides into glass on the viscosity and melting temperature was interpreted by changes in structure of soda-lime-silicate glasses doped with rare earth oxides.     

磁性薄膜的晶格结构和磁性

采用Monte-Carlo模拟方法对六边形、正方形和三角形晶格结构磁性薄膜的磁学特性及磁畴结构进行了模拟,结果表明,磁性薄膜的磁性特征及其磁相变温度和薄膜结构密切相关并存在临界膜厚,当薄膜厚度大于临界膜厚时薄膜磁性特征稳定.在低温区,不同结构磁性薄膜的磁滞回线均出现台阶现象,结果同相关实验一致.     

The structure and helicity of perfluorooctanonitrile, CF3–(CF2)6–CN

New molecular structural data is presented for a cyanide terminated oligomer of polytetrafluoroethene. The target molecule, CF₃–(CF₂)₆–CN, has been seeded within a pulsed supersonic expansion of argon. The result of this action is to cool the species to rotational temperatures below 4 K. Within this state, the pure rotational spectrum of the oligomer has been recorded using two types of Fourier transform microwave spectroscopy. A total of 111 transitions have been identified involving rotational J levels between 6 and 40. Only a- and b-type transitions were observed. The spectrum has been analyzed using a Hamiltonian containing all three rotational constants and one centrifugal distortion constant, D_J. The experimental spectroscopic constants have been used to develop an effective molecular structure by scaling the quantum chemical calculated structure. The data shows that the seven carbon perfluorinated chain for the isolated oligomer twists ≈104°. This compares well to the C₇F₁₃-twist of ≈97° anticipated from the X-ray structure of phase II polytetrafluoroethene.     

模糊共生结构的加细及其性质

介绍模糊拓扑,模糊邻近,模糊拟一致框架下的模糊(半)拓扑序、模糊共生结构的概念,研究模糊(半)拓扑序,模糊共生结构的加细,得到一些重要性质。     

1-氨甲基-6,7-二甲氧基-1,2,3,4-四氢异喹啉盐酸盐的合成及表征

以3,4-二甲氧基苯乙胺为原料,经氯乙酰氯酰化得到N-氯乙酰基-3,4-二甲氧基苯乙胺,通过与邻苯二甲酰亚胺钾烃化,在P2O5的作用下经Bischler-Napieralski环合后,用水合肼肼解,硼氢化钾还原后与盐酸作用得1-氨甲基-6,7-二甲氧基-1,2,3,4-四氢异喹啉盐酸盐。产品结构经IR、1H NMR、MS确证。     

1-氯甲基-6,7-二甲氧基-1,2,3,4-四氢异喹啉盐酸盐的合成和结构表征

以3,4-二甲氧基苯乙胺为原料,经酰化,比西勒-纳皮拉尔斯基（Bischler-Napieralski）反应,还原,盐酸成盐合成1-氯甲基-6,7-二甲氧基-1,2,3,4-四氢异喹啉盐酸盐,总收率41.1%。目标物及中间体经IR,1H NMR进行结构表征。     

一维链状席夫碱锰（Ⅱ）配合物的合成及结构表征

以1S,2S-环己二胺和乙酰丙酮进行缩合得到N,N′-双（乙酰丙酮）-1S,2S-环己二胺的Schiff碱配体L,再将配体L与MnCl2.4H2O进行配位反应,得到了配合物[MnL2Cl2.L]n（1）,并用元素分析和X射线单晶衍射进行了表征。结果表明,配合物1属于正交晶系,空间群是P212121,晶体参数：a=1.56630（15）nm,b=1.59373（16）nm,c=2.1963（2）nm,V=5.4827（9）nm3,Z=4,Dc=1.164g.cm-3,R1=0.0548,wR2=0.1368。在配合物1中,每个Mn（）的配位环境都是三角双锥。配合物中双齿配体通过其两臂乙酰丙酮亚胺单元的端基氧原子同2个金属离子配位桥联形成一维螺旋链结构。     

Structure and physiochemical characteristics of whey protein isolate conjugated with xylose through Maillard reaction at different degrees

The purpose of this study is to prepare Maillard reaction products (MRPs) with both good emulsification and antioxidant activity, and the relationship between the Maillard reaction degree and structural changes of whey protein isolate (WPI) conjugated with xylose through wet-heating was explored. Browning intensity didn’t change while the free amino groups reduced significantly at the initial stage of Maillard reaction (MR). Amino acid analysis indicated that the lysine and arginine reduced significantly. The antioxidant property of the MRPs was significantly improved. The best emulsifying properties could be obtained in the middle degree of MR. The sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis illustrated that WPI and xylose formed high molecular weight conjugates. The circular dichroism spectra suggested that α-helix and random coil were increased while the β-sheet and β-turns were decreased after the MR. All of the MRPs exhibited a marked red shift in the maximum fluorescence intensity, indicating that the hydrophilicity of MRPs was enhanced.     

Comparative study of CO2 hydrogenation to methanol on cubic bixbyite-type and rhombohedral corundum-type indium oxide

Hydrogenation of CO₂ to value-added chemicals has attracted much attention all through the world. In₂O₃ with cubic bixbyite-type (denoted as c-In₂O₃) is well known for its high CO₂ hydrogenation activity and CH₃OH selectivity at high temperature. However, the other structure of In₂O₃ with rhombohedral corundum-type (denoted as rh-In₂O₃) rarely been investigated as catalyst. Herein, c-In₂O₃ and rh-In₂O₃ were prepared and comparatively studied for CO₂ hydrogenation. The results indicated that c-In₂O₃ showed higher CO₂ conversion activity than rh-In₂O₃ due to the impressive reducibility and reactivity. Whereas rh-In₂O₃ had higher CH₃OH selectivity due to weaker CH₃OH and stronger CO adsorption on rh-In₂O₃. Although c-In₂O₃ and rh-In₂O₃ catalysts showed different CO₂ hydrogenation performance, in-situ diffuse reflectance infrared Fourier transform spectroscopy showed CO₂ can be reduced to CO through redox cycling and hydrogenation to CH₃OH through formate path.