柱[5]芳烃对偶氮二异丁腈分子识别的研究及应用

以三氟化硼乙醚为催化剂、1,4-对甲氧基苯和多聚甲醛为原料合成具有高亲和性的全甲氧基柱[5]芳烃,通过核磁共振氢谱、紫外可见光谱、荧光光谱等检测手段研究了全甲氧基柱[5]芳烃对偶氮二异丁腈的分子识别能力。结果表明,全甲氧基柱[5]芳烃和偶氮二异丁腈可在氯仿中形成1∶1的主客体络合物,同时,全甲氧基柱[5]芳烃对偶氮二异丁腈具有刺激响应性,可作为荧光分子探针检测偶氮二异丁腈。     

湘西地区微细粒级难选菱锰矿浮选试验研究

湘西地区菱锰矿呈细粒或微细粒状态嵌布,且脉石繁多结构复杂,属于难选菱锰矿。采用X射线荧光光谱、X射线衍射及MLA等方法对菱锰矿进行了全面的工艺矿物学研究。针对微细粒级难选菱锰矿,以合适的Mn品位和回收率为指标,考察了磨矿细度、pH调整剂用量、抑制剂用量以及捕收剂用量对菱锰矿浮选的影响。试验表明,菱锰矿(Mn品位9.93%)在磨矿细度-0.074 mm 95.66 %的条件下,采用"一粗一精一扫"的正浮选试验流程,可获得精矿Mn品位19.04 %、Mn回收率88.86 %的浮选指标。     

Fabrication of fullerene decorated by iron compound and its effect on the thermal stability and flammability for high-density polyethylene

Fullerene decorated by iron compound (C₆₀-Fe) is fabricated via solution reaction and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), wide-angle X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Upon incorporating C₆₀-Fe into high-density polyethylene (HDPE) matrix by melt blending, the thermal and thermo-oxidative stability of HDPE are considerably increased, the oxidative induction time (OIT) is dramatically extend. When the concentration of C₆₀-Fe reached 5 wt%, the onset degradation temperature in air increased from 352°C to 422°C, and the OIT dramatically delayed from 4.5 to 47.8 minutes. Moreover, from microscale combustion calorimetry (MCC), C₆₀-Fe can reduce the peak heat release rate (PHRR), heat release capacity (HRC), and total heat release (THR) values of the composites, all of which are very important parameters for evaluating the fire retardancy of a polymeric material.     

Pr3+掺杂对CaBi8Ti7O27陶瓷电学和光学性能的影响

采用传统固相法合成了Pr3+掺杂的CaBi8Ti7O27(CBT-BIT-xPr3+,0≤x≤0.020)共生铋层状结构多功能陶瓷材料,并研究了Pr3+掺杂对CaBi8 Ti7 O27陶瓷样品的结构、电学和光学性能的影响.结果表明,所有样品均为单一的正交相共生铋层状结构,适量的Pr3+掺杂未明显改变陶瓷样品的居里温度;随着Pr3+掺杂量的增大,陶瓷样品的介电损耗tanδ逐渐降低,压电常数d33由7 pC/N逐渐提升至11 pC/N;在450 nm波长光源的激发下,Pr3+掺杂后的样品可在611 nm处观测到一个较强的红光发射峰,并且其荧光强度随Pr3+掺杂量的增加而逐渐增强.     

规整有机分子自聚集体对铜的高效缓蚀的研究

通过多步法合成了离子型含双苯并三氮唑环的目标分子，4，4'-{苯-1，3-二基二[(1E)-3-羰基丙-1-烯-1，3-二基]}二[2-(2H-苯并三唑-2-基)苯醇酸]二钾。在室温条件下，目标分子在3.5%（质量）NaCl/DMSO（二甲基亚枫）混合溶液 （体积比：40/60） 中能够发生分子自组装产生纳-微米级的自聚集体。通过傅里叶变换红外光谱 （FT-IR）、拉曼光谱和X射线光电子能谱 （XPS） 的表征，证实了所形成的目标分子自聚集体能够对铜表面产生强烈的化学吸附作用，在铜表面形成自组装膜。利用电化学方法测定了目标分子自聚集体吸附在铜表面形成自组装膜后，在3.5%（质量）NaCl溶液中的缓蚀性能。结果表明目标分子自聚集体在NaCl溶液中能高效地抑制铜腐蚀。     

煤红外快速热解过程中床层对二次反应的影响

针对煤快速热解研究中样品添加量少(mg级)、焦油收集难等问题，本研究利用压片法制备微薄厚度(mm级)的煤层，并采用红外加热装置考察大添加量(g级)、微薄煤层的快速热解特性。对比堆积煤样和不同煤压片厚度(1.5~3 mm)与个数(1~2)的压片煤样热解特性发现，压片煤层热解过程的二次反应受到明显抑制，焦油产率急剧增加，在1000℃时达9.96%，为格金分析的1.5倍，实现油气产量的同步增长。模拟蒸馏分析发现，堆积状态下焦油以沥青质为主，而微薄煤层制焦油含大量轻油、酚油、萘油、洗油和蒽油。GC-MS和FTIR分析表明，随煤层厚度和个数的减少，焦油组分和含量提高，芳香烃类和含氧官能团吸收增加，进一步验证煤快速热解过程中煤层厚度对焦油产率和品质的影响，揭示在二次反应充分抑制下煤高温热解的初级反应特性。     

A novel model for high-speed angular contact ball bearing by considering variable contact angles

Journal of Mechanical Science and Technology - In this study, on the basis of the various contact angles and the hybrid theory, a new mathematic model without the raceway control hypothesis is...     

Stable Organic Titanium Catalysts and Reactive Distillation Used for the Transesterification of Dimethyl Carbonate with Phenol

The transesterification of dimethyl carbonate with phenol to methyl phenyl carbonate (MPC) was investigated on novel catalysts such as titanium diisopropoxide bis(ethyl acetoacetate) and titanium dibutoxide bis(ethyl acetoacetate) in a closed batch reactor at 185–206 °C under high pressure. The produced methanol could be removed efficiently by reactive distillation in order to overcome the equilibrium. The prepared catalysts have higher resistance to water than titanium alkoxides. Phenol conversion as high as 86.4 % with an MPC selectivity of 99.4 % was achieved under optimal reaction conditions within 9 h. Most of the catalytic activity was retained after repeated use for ten times.     

线性富磷化阻燃剂在聚氨酯泡沫中的应用研究

通过界面聚合法合成了一种线性富磷化阻燃剂（LPRFR），将LPRFR与可膨胀石墨（EG）复配制备了阻燃聚氨酯泡沫（RPUF），使用红外光谱分析仪、核磁共振分析仪对阻燃剂LPRFR的化学结构进行了表征，并通过极限氧指数仪、锥形量热仪、扫描电子显微镜和红外光谱分析仪对RPUF的燃烧性能、微观形貌和化学结构进行了分析。结果表明，仅10 %（质量分数，下同）的LPRFR 与8 %EG复配后，RPUF的极限氧指数（LOI）便达到26.1 %；LPRFR和EG能大幅降低RPUF的热释放速率，并提高基体的成炭能力； LPRFR参与了燃烧过程中的成炭反应，形成了含P—O—C及P=O结构的高质量炭层，有效隔绝了氧气和热量；LPRFR是一种对于聚氨酯泡沫阻燃性能优异的新型阻燃剂。