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Fe_3O_4单晶纳米棒和量子点的水热合成与表征 总被引:1,自引:1,他引:0
本文以FeSO_4·7H_2O为铁源,采用LSS反应机制控制合成了Fe_3O_4单晶纳米棒和量子点,并根据不同反应条件下反应生成的产物形貌推断了反应机理.采用X-射线衍射仪(XRD)、透射电子显微镜(TEM)对产物进行表征.室温下分别测试了Fe_3O_4单晶纳米棒和量子点的磁滞回线,检测得到纳米棒和量子点饱和磁化强度磁化率(Ms)分别为44.26 emu/g和60.09 emu/g,矫顽力(H_c)分别为132.3 Oe和143.2 Oe. 相似文献
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探究了二维石墨烯片(GNPs)对复合相变材料导热性的影响,以芒硝基复合相变材料(SCNa)为原料,制备出石墨烯片增强芒硝基复合相变材料(SCNaG).探讨了GNPs添加量对SCNa相变材料导热率的影响,并对其过冷机理进行了讨论.结果表明:复合相变材料导热系数随着GNPs添加量呈线性增加,当GNPs=0wt;时,相变材料导热系数为0.854 W/(m·K);当GNPs=3wt;时,相变材料导热系数为1.405 W/(m·K);随着GNPs添加量的增大相变材料过冷度先减小后增大,当GNPs=0.5wt;时,过冷度低于纯SCNa相变材料,为2.5℃C,当GNPs=3wt;时,过冷度增大至10.9℃.GNPs的添加量对相变材料相变温度影响不大,相变潜热略有减小. 相似文献
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基于节能减排的重要性,针对Na2 SO4·10H2 O基相变材料相变过程中液相泄露和长期使用的热稳定性问题,采用直接浸渍的方法将其封装入不同载体(SiO2气凝胶、X型分子筛、膨胀珍珠岩、活性炭和硅藻土)中,成功制备了不同载体的定形相变材料.通过SEM、XRD、DSC等表征方法,测定了饱和吸附时各自的相变材料占比分别为80.0;、82.2;、76.9;、89.2;及60.6;;并且从热性能、机械性能、成本等方面综合对比了不同载体的性能,发现膨胀珍珠岩(EP)是性价比最优的载体材料.进一步对Na2 SO4·10H2 O/EP复合相变材料进行了熔冻循环实验测试,经过100次循环实验,热值损耗保持在15;以内,过冷度稳定在10℃以内,热稳定性良好. 相似文献
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以芒硝(Na2SO4· 10H2O)为主相变材料,采用物理共混法,筛选出合适添加辅助材料组成多元混盐体系,制备出相变温度在25℃左右的Na2SO4· 10H2O基复合相变材料,研究了原料配比对相变材料相变温度和相变潜热的影响.通过热重分析、T-history曲线、差示扫描量热法等表征了制备的芒硝基相变储能材料性质.结果表明:二元相变材料相变温度随着Na2CO3·10H2O增加而先降低后增大;相变材料相变潜热密度基本不变.三元相变材料相变温度随着NaCl、KCl、NH4Cl量增加相变温度降低;相变材料相变潜热密度相比于二元体系有所减小,且在一定范围内随着成核剂硼砂含量的增加该体系相变潜热密度基本保持不变,过冷度有明显下降.当Na2SO4· 10H2O量为86.4;、Na2CO3 · 10H2O量为9.6;、NaCl量为4;,对该配方改性添加3;的硼砂和0.1;的羧甲基纤维素钠时,此相变材料的相变温度为24.6℃,过冷度为0.3℃,相变潜热密度为179.6 J/g. 相似文献
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A. L. Bingham J. E. Drake C. Gurnani M. B. Hursthouse M. E. Light M. Nirwan R. Ratnani 《Journal of chemical crystallography》2006,36(10):627-630
Triethyl ammonium Salt of O,O′-bis(p-tolyl)dithiophosphate and O,O′-bis(m-tolyl)dithiophosphate have been obtained by reaction of p- and m-cresol, respectively with P2S5 in toluene and have been characterized by elemental analysis, IR, 1H and 31P NMR spectroscopy. The molecular structure of O,O′-bis(p-tolyl)dithiophosphate has been determined. Crystal data: [Et3NH]+[(4-MeC6H4O)2PS2]−: Monoclinic, P21/c, a=15.2441(9) ?, b=10.415(2) ?, c=3.9726(9) ?, β=91.709(7)°, V=2217.5(1) ?−3, Z=4.Supplementary materials Additional material available from the Cambridge Crystallographic Data Centre (CCDC no. 600927 for [Et3NH]+[(4-MeC6H4O)2PS2]− comprises the final atomic coordinates for all atoms, thermal parameters, and a complete listing of bond distances and angles. Copies of this information may be obtained free of charge on application to The Director, 12 Union Road, Cambridge CB2 2EZ, UK (fax: +44-1223-336033; email: deposit@ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk). 相似文献
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We perform first-principles coexistence simulations of the low-density and the high-density phases of supercooled liquid silicon and find a negative slope for the coexisting line in the temperature-pressure plane. Electron density maps and electron-localization function plots of the two phases of silicon show marked differences. The calculated differences suggest more localized electrons in the low-density liquid compared to the high-density liquid, coming from an increased population of covalent bonds, which further explain the calculated negative slope in the two phase coexistence regime. This is consistent with the presence of a pseudo-gap in low-density liquid silicon, absent in the high-density liquid which shows a metallic behavior. 相似文献
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Tosha Barclay Wallace Cordes Fu-May Yang Shaw-Tao Lin 《Journal of chemical crystallography》1997,27(6):359-362
Structures of both thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane, ?C6H4?CH2SCH2?C6H10?CH2SCH2?, have been determined, wherecis andtrans refer to the attachments to the cyclohexane ring. Thecis form crystallizes in the monoclinic space groupP21/c witha=8.4299(11)Å,b=21.772(2)Å,c=8.9724(13)Å, β=116.574(11)o, andZ=4. Thetrans isomer packs into the monoclinic space groupP21 witha=8.159(16)Å,b=10.185(5)Å,c=9.558(2)Å, β=112.435(18)o, andZ=2. The cyclohexane ring of thecis isomer is in the chair conformation, while the cyclohexane of thetrans isomer is found in a twisted boat conformation. 相似文献
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以表面活性剂CTAB和SDBS为化学添加剂,采用化学共沉淀法对碳酸锶晶体的生长形态进行调控,成功地制备出了实心的树枝状和花瓣为空心的花状碳酸锶粉体,并用X射线衍射(XRD)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FT-IR)等分析手段对样品进行了表征;最后重点对化学添加剂可能产生的影响机理进行了初步的探讨.结果表明,CTAB和SDBS在晶体生长的过程中能起到显著的影响作用,两者对粒子分散性能的作用效果相反,而且后者对晶体(013)和(213)晶面表面能降低的贡献明显大于前者. 相似文献
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Lin Zhu Karl Seff Thomas Witzke Lutz Nasdala 《Journal of chemical crystallography》1997,27(5):325-329
The structure of Zn4Na(OH)6SO4Cl·6H2O, a secondary mineral from Hettstedt, Germany, was determined by single-crystal X-ray diffraction. The crystals are hexagonal,a=8.413(8),c=13.095(24) Å, space group $P\bar 3$ , Z=2. The structure was refined to R=0.0554 and Rw=0.0903 for 970 reflections with I≥3σ(I). The structure can be described as zinc hydroxide layers perpendicular toc, from which sulfates and chlorides extend. The layers are held together by a system of hydrogen bonds involving hexaaquo Na+ ions which occupy the interlayer space. 相似文献
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Jerry P. Jasinski Ray J. Butcher Anil N. Mayekar H. S. Yathirajan B. Narayana B. K. Sarojini 《Journal of chemical crystallography》2009,39(10):761-765
Abstract The title compound, C18H18BrN3O3S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) ?, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol
ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine
ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely
packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional
series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene
group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the
crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal]
reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving
support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these
angles which therefore play a role in stabilizing crystal packing.
Graphical Abstract Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C18H18BrN3O3S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Zun-Ting Zhang Xue-Ling Zhang Bo-Lun Yang Yao-Dong Zhang 《Journal of chemical crystallography》2006,36(7):407-411
Irisolidone (5,7-dihydroxy-6,4′-dimethoxyisoflavone) was isolated from the flowers of Pueraia lobata and its crystal structure was examined by X-ray single crystal diffraction. The crystal structure of irisolidone is monoclinic, space group P21/c with a = 15.491(9) ?, b = 7.895(4) ?, c = 13.321(7) ?, β = 110.546(9)° and Z = 4. Hydrogen bonding and aromatic π–π stacking assemble the title compound into a three-dimensional networking structure. 相似文献
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Maurizio Remelli Fernando Pulidori Remo Guerrini Valerio Bertolasi 《Journal of chemical crystallography》1997,27(9):507-513
The natural amino acid L-Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid) has been synthesized following a new pathway which gives a chemically and optically pure product with an excellent yield. The crystal structures of a synthetic intermediate, Nπ-hydroxymethyl-spinacine, and a spinacine derivative, Nα-methyl-spinaceamine, have been investigated through X-ray diffraction: Spi(πMeOH)·H2O, monoclinicP2 i,a=8.571(1),b=6.682(1),c=8.588(1) Å, and β=94.67(1)o. Spm(αMe)·2HCl·H2O, triclinicP l,a=7.492(4),b=10.799(3),c=7.040(2) Å, α=91.88(2), β=98.36(3) and γ=73.34(3)o. Spi(πMeOH) crystallizes with a water molecule and displays a zwitterionic character. The carboxylate group is in equatorial position and forms a short electrostatic interaction of 2.618(2) Å between one of its oxygens and the protonated nitrogen of the tetrahydropyridine ring. The crystal packing is assured by strong O?H???O, O?H???N, N?H???N intermolecular hydrogen bonds and C?H???O close contacts. The biprotonated compounds Spm(αMe) crystallizes with two Cl? anions and a water molecule. The positive charge on the imidazole ring is delocalized on the conjugated moiety N=C?N. The crystal is built up by clusters formed by two biprotonated Spm(αMe) molecules, four Cl? anions and two water molecules linked together by hydrogen bonds. 相似文献
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Maurizio Remelli Fernando Pulidori Remo Guerrini Valerio Bertolasi 《Journal of chemical crystallography》1991,27(9):507-513
The natural amino acid L-Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid) has been synthesized following a new pathway which gives a chemically and optically pure product
with an excellent yield. The crystal structures of a synthetic intermediate, Nπ-hydroxymethyl-spinacine, and a spinacine derivative, Nα-methyl-spinaceamine, have been investigated through X-ray diffraction: Spi(πMeOH)·H2O, monoclinicP2
i,a=8.571(1),b=6.682(1),c=8.588(1) ?, and β=94.67(1)o. Spm(αMe)·2HCl·H2O, triclinicP
l,a=7.492(4),b=10.799(3),c=7.040(2) ?, α=91.88(2), β=98.36(3) and γ=73.34(3)o. Spi(πMeOH) crystallizes with a water molecule and displays a zwitterionic character. The carboxylate group is in equatorial
position and forms a short electrostatic interaction of 2.618(2) ? between one of its oxygens and the protonated nitrogen
of the tetrahydropyridine ring. The crystal packing is assured by strong O−H−−−O, O−H−−−N, N−H−−−N intermolecular hydrogen
bonds and C−H−−−O close contacts. The biprotonated compounds Spm(αMe) crystallizes with two Cl− anions and a water molecule. The positive charge on the imidazole ring is delocalized on the conjugated moiety N=C−N. The
crystal is built up by clusters formed by two biprotonated Spm(αMe) molecules, four Cl− anions and two water molecules linked together by hydrogen bonds. 相似文献