Structure and growth phenomena of C60 and C70 single crystals

C₆₀ and C₇₀ single crystals free from solvent contamination grew from their vapour. Large C₆₀ crystals up to a size of about 5 mm×3 mm×3 mm and C₇₀ crystals about 1 mm×1 mm×1 mm were obtained. C₆₀ crystals with fcc structure showed two types of morphological faces, namely {111} and {100}, frequently with twinning on {111} face. C₇₀ crystals obtained have a hcp structure witha=10.1 ? andc=16.7 ?. DSC and X-ray diffraction analysis indicated that C₇₀ crystal underwent phase transition below 100 C. Morphological observation suggests that the growth of C₆₀ and C₇₀ single crystals is based on layer-spreading mechanism. Synopsis of the first author Li Jing, professor, born in 1954, received Ph D degree in 1988, professional interests are physicel chemistry in metallurgy and materials, fullerene chemistry and ceramics.     

Microstructure and Wear Resistance of Fe4CoCrNiB0.2Mox(x=0,0.5,1) High Entropy Alloys

To improve the wear resistance of Fe₄CoCrNiB_0.2 high-entropy alloy (HEA),the Fe₄CoCrNiB_0.2Mo_x (where,x in Fe₄CoCrNiB_0.2Mo_x is a molar content,and the value is 0,0.5,1,respectively) HEAs were prepared on the Q235 substrate by laser cladding.The structure,hardness,and wear resistance of Fe₄CoCrNiB_0.2Mo_x HEAs were investigated using scanning electron microscopy with spectroscopy ...     

高钨高硅电炉锡渣的相组成及形成机理研究

采用化学分析，化学物相分析，Ｘ射线衍射，电子探针、光学显微镜鉴定等研究手段，查明了高钨高硅电炉锡渣中的相组成及化学元素在各相中的分配以及渣中各相相对百分含量、结构构造、各矿物相的嵌布关系和结晶粒度等，并据此进行了渣型讨论及机理研究，为烟化法处理该复杂物料提供了理论依据，也是完善冶炼工艺和条件的前提和基础     

Abrasion Resistance of Cement Paste with Granulated Blast Furnace Slag and Its Relations to Microhardness and Microstructure

The abrasion resistance of cement pastes with 30 wt%,40 wt% and 50 wt% granulated blast furnace slag (GBFS),and its relations to microhardness and microstructure like hydration products and pore structure were studied.Results indicated that GBFS decreased the abrasion resistance of paste,and among the pastes with GBFS,the paste with 40 wt% GBFS showed the highest abrasion resistance.The microhardness of GBFS was lower than that of the cement,and the microhardness of the hydration products in pas...     

改性β沸石催化剂上混合C4的气相烷基化反应研究

对烷/烯比较小（4.5∶1）的混合C     

船闸用纤维混凝土耐撞磨性能与机理分析

采用掺I级粉煤灰、PVA纤维和聚羧酸类超塑化剂的"三掺技术"配制了船闸闸室墙耐撞磨高性能混凝土,研究了水泥品种、粉煤灰掺量和有机纤维对混凝土耐撞磨性能的影响规律.结果表明:掺PVA纤维可明显改善混凝土的耐撞磨性能和抗冲击性能;采用的船闸工程混凝土耐撞磨性能试验方法用于混凝土耐撞磨性能的测定和评价是可行的.     

水泥窑中高硫煤脱硫过程探讨

以ＣａＣＯ３、ＢａＣＯ３、Ｓｒ（ＮＯ３）２为脱硫剂．对水泥窑中高硫煤的燃烧脱硫过程进行探讨。依据差热分析、Ｘｒａｙ衍射分析结果，对高硫煤的燃烧及其流转化形式、脱硫反应等进行研究，同时借助ＳＣ－１３２定硫仪．分析讨论了ＣａＣＯ３、ＢａＣＯ３、Ｓｒ（ＮＯ３）２等脱硫剂在８００℃～１４００℃温度范围的脱硫效果。     

钢渣在水泥熟料烧成中的作用及其机理

通过对原材料化学组成的分析，发现在水泥熟料烧制中钢渣不仅可以作石灰质及铁质原料，而且可以作为“晶种”，有利于水泥熟料的煅烧。因此将钢渣作为独立组分，利用自编全组分水泥配料计算系统在较大率值范围内，进行大量计算并分析规律，选取配比进行烧成实验。结果表明：在生料中掺入钢渣不仅可以降低硅氧率，明显减少f-CaO含量，提高熟料质量，而且能够降低环境负荷，具有良好的经济效益、社会效益和环境效益。     

Effect of CaCO3 on hydration characteristics of C3A

Hydration products and morphology characteristics of C₃A (tricalcium aluminate)-CaCO₃-H₂O system were studied by means of XRD, DSC, FTIR spectrum analysis and SEM. The results indicate that, the new phases, i.e., C₃A·0.5CaCO₃·0.5Ca(OH)₂·11.5H₂O and C₃A·CaCO₃·11H₂O are found in this system due to the activity of CaCO₃; the formation of C₄AH₁₃ and C₂AH₈ is prohibited and the generation of C₃AH₆ is delayed in the early hydration process. C₃A·0.5CaCO₃·0.5Ca(OH)₂·11.5H₂O is not stable and will be totally transferred within 24 h; C₃A·CaCO₃·11H₂O exists stably once formation, and its flake-like crystalline phases in the early hydration transform to long rod shape, and to finally fine-needle at 28 d.     

不同压力下层流对冲C2 H4扩散火焰中碳烟生成的数值模拟研究

采用Chemkin中的对冲扩散火焰模型对C₂H₄对冲扩散火焰中碳烟颗粒的生成进行了数值模拟研究,重点关注不同压力下碳烟颗粒及部分气相小分子和前驱物的形成. 以0.1 atm为增量,探讨了1～5 atm内乙烯扩散火焰中多种中间产物和碳烟前驱物的浓度分布. 数值模拟结果表明,随着压力的不断增大,碳烟体积分数和碳烟数密度快速增加,H₂、CH₄等气相小分子的含量总体呈现下降趋势但变化不大,火焰面及气相小分子的生成区域变小. PAHs和C₂H₂含量的快速增加是通过HACA机理实现的,使得碳烟成核和生长速率加快,从而促进了碳烟数密度和体积分数的迅速增加.     

Effect of TiO2 on the formation of clinker with high C3S

Effect of TiO₂ content on the burnability of clinker with high C₃S were investigated by determination of free lime in final product, and the clinker phase formation, microstructural features of C₃S and the solubility of TiO₂ in C₃S were further studied by XRD, SEM/EDS analysis. TiO₂ accelerates the combination of free lime in the samples, free lime content decreases obviously with TiO₂ increasing up to 2% and almost remains above 2%. A new phase CaO·TiO₂ was found when TiO₂ was up to 3%, and samples with TiO₂ displayed well-formed uniform size hexagonal C₃S crystal. The limit of solubility of TiO₂ in C₃S at 1400 °C is about 1.7%.     

Formation mechanism of multi-functional black silicon based on optimized deep reactive ion etching technique with SF6/C4F8

This paper reports a controllable multi-functional black silicon surface with nanocone-forest structures fabricated by an optimized deep reactive ion etching(DRIE)technique using SF6/C4F8 in cyclic etching-passivation process,which is maskless,effective and controllable.The process conditions are investigated by systematically comparative experiments and core parameters have been figured out,including etching process parameters,pre-treatment,patterned silicon etching and inclined surface etching.Based on the experimental data,the formation mechanism of nanocone shape is developed,which provides a novel view for in-depth understanding of abnormal phenomena observed in the experiments under different process situations.After the optimization of the process parameters,the black silicon surfaces exhibit superhydrophobicity with tunable reflectance.Additionally,the quantitative relationship between nanocones aspect ratio and surface reflectance and static contact angle is obtained,which demonstrates that black silicon surfaces with unique functional properties(i.e.,cross-combination of reflectance and wettability)can be achieved by controlling the morphology of nanostructures.     

煤中灰分在水泥熟料烧成中的作用及其机理

通过在水泥生料中掺加不同品质高灰分煤的煤灰,研究了灰分及其组分在硅酸盐水泥熟料液相变化、矿物形成及微观结构中的作用及机理。结果表明,灰分含量的升高是降低液相初析温度的主要原因。随着灰分含量的升高,熟料中间相中Al和Fe的含量增加,尤其固溶的Si明显增多,造成液相粘度增加,阻碍C3S形成。同时,造成熟料矿物分布的均匀性更差,熔蚀现象更多。     

丁苯橡胶与白炭黑相互作用对磨耗性能的影响

选择3种不同结构的丁苯橡胶为基体,研究了白炭黑用量以及白炭黑与橡胶间的相互作用对硫化胶阿克隆(Akron)磨耗和DIN磨耗性能的影响规律。研究结果表明,溶聚丁苯橡胶SSBR72606与白炭黑相互作用最强,SSBR2557A次之,而ESBR1502最低。对于Akron磨耗,ESBR1502达到最高耐磨性时白炭黑用量为60份,而SSBR2557A为50份,SSBR72606为40份。这说明与白炭黑作用力越强,达到最佳耐磨性时白炭黑的用量越少。对于DIN磨耗,随白炭黑用量的增加,3种硫化胶的耐磨性能提高,但当白炭黑用量高于40份时,白炭黑用量再增加对3种硫化胶的耐DIN磨耗性能影响不大。     

高温对水泥石结构和性能的影响及机理分析

采用空气养护、水中养护(标准养护)两种养护方式和0.35,0.45,0.55三个水灰比模拟通用C30混凝土结构中的不同位置(表面、水泥浆体和界面区),利用DSC、XRD和SEM等测试分析方法,研究其在火灾发展的不同阶段(20℃,100℃,200℃,300℃,400℃,500℃,600℃,700℃)强度、水化产物和微观结构的变化.结果分析表明,在相同养护条件和冷却方式下,水泥石的强度随水灰比的降低而增加,不同水灰比水泥石的强度随灼烧温度变化趋势类似;水灰比相同时,水中养护的水泥石强度比空气养护的水泥石的强度大、抗高温破坏性能好;水泥石结构在高温下破坏的极限温度范围在500℃~550℃,主要受水泥石中C-S-H凝胶、Ca(OH)2等水化产物在高温下分解程度影响.     

球磨时间对Ti(C0.7,N0.3)晶粒及Ti(C0.7,N0.3)基金属陶瓷组织和性能的影响

球磨是金属陶瓷制备中的关键工艺,滚动球磨是目前成本较低、在实际工业生产中应用最广泛的球磨方式。为了量化分析球磨时间对Ti（C_0.7,N_0.3）基金属陶瓷的影响,采用湿混的方法在固定的球料比、球磨机转速和球磨介质添加量的条件下,研究球磨时间因素对Ti（C_0.7,N_0.3）的晶粒尺寸、应变和晶格常数的影响,以及对烧结后的Ti（C_0.7,N_0.3）基金属陶瓷微观组织和物理力学性能如收缩率、密度、硬度和横向断裂强度的影响。结果表明,随球磨时间增加,Ti（C_0.7,N_0.3）晶粒尺寸下降,而微观应变增加。同时,Ti（C_0.7,N_0.3）的晶格常数也增加,这与晶粒微观应变增加以及少量原料的氧化加剧有关。对烧结后的微观组织而言,球磨时间的增加导致金属陶瓷硬质相平均晶粒尺寸下降,但是当球磨时间达到72和96 h的时候,金属陶瓷中出现了0.1 μm左右的孔隙,这与球磨过程中氧含量的增加导致烧结时脱气反应以及Ti（C,N）硬质相和Ni粘接剂之间的润湿性变差有关。Ti（C_0.7,N_0.3）基金属陶瓷微观组织中白芯结构数量随球磨时间的增加明显减少了,芯中Mo含量的下降而Ti含量的增加是白芯数量下降的原因。环形相随球磨时间的增加变薄了,这一现象与不同尺寸的颗粒溶解度以及颗粒的均匀性有关。另外,随着球磨时间的增加,Ti（C_0.7,N_0.3）基金属陶瓷的硬度增加,而横向断裂强度随球磨时间的增加先增加后下降,其中孔隙对横向断裂强度的损害作用要大于晶粒细化对强度提高的作用。     

对称C4二硫醚—丙酮—水三元体系在308.15K下的液液平衡研究

对称C4二硫醚—丙酮—水三元体系是在合成对称C4二硫醚的工艺中碰到的一个比较新的体系.在常压308.15 K下,用浊点法,平衡釜法分别测定对称C4二硫醚—丙酮—水三元体系的溶解度数据和结线数据(对称C4二硫醚包括正丁基二硫醚、仲丁基二硫醚和叔丁基二硫醚),得到了三元液液平衡体系的共轭相组成并由此绘得相平衡曲线.用内标法准确地测定了对称C4二硫醚及丙酮的含量,在单相区域对实验进行了验证实验均方误差1.56%.对称C4二硫醚—丙酮—水三元体系的研究结果表明有利于回收对称C4二硫醚.研究有利于对称C4二硫醚清洁合成工艺的设计和控制.     

TiO2对高C3S熟料烧成的影响

通过外掺TiO₂来改善高C₃S熟料的烧成.配制7个生料样品,其潜在矿物组成均为w(C₃S)=75%、w(C₃A)=7%、w(C4AF)=18%,TiO₂掺量分别为0、05%、10%、15%、20%、25%、30%,在设定的高温下煅烧成熟料,通过化学分析、XRD、SEM/EDS等方法,研究了TiO₂对熟料易烧性、矿相形成、C₃S晶体形貌和熟料强度等的影响.结果表明,掺入少量TiO₂明显提高了熟料的易烧性;当TiO₂掺量小于2%时,f-CaO随TiO₂掺量的增加而显著降低;当TiO2掺量超过2%后,f-CaO随TiO₂掺量的变化不大;当TiO₂掺量达到3%时,在1 350和1 400 ℃温度煅烧的熟料中均发现了CaO·TiO₂新相;掺2%TiO2在1 400℃煅烧条件下的熟料,TiO₂在C₃S中的固溶量约1.7%;掺入适量的TiO₂,熟料中C₃S结晶比较完整、均匀,熟料强度较高.适当掺入TiO₂对改善高C₃S熟料的烧成和提高其强度都是有利的.     

C0类半群的稳定性和Hilbert空间中的随机发展方程

给出Hilbert空间上C0类线性算子半群的指数稳定性的一个等价条件.作为应用,指明了某一类线性随机发展方程的弱指数稳定与指数稳定的等价性.