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关键词： Wood   Fluidized bed combustor   Devolatilization   Shrinkage   CT detection  

摘要： Computed tomography (CT) was used to scan the samples obtained from devolatilization in a turbulent fluidized bed combustor (FBC). The evolution of three-dimensional shrinkages at different residence time was measured and visualized successfully without destroying the sample. The effects of the bed temperature, and the fuel species on the mass conversion, devolatilization time, and shrinkage characteristics were also investigated. Four common Chinese wood types, poplar, Chinese fir, oak, and teak were used. The results show that the shrinkage and mass conversion increase with increasing residence time. In addition, the devolatilization time and final tangential and radial shrinkages decrease with increasing bed temperature. The final longitudinal shrinkage shows an inverse trend compared with the other two shrinkages. The tangential shrinkage is slightly greater than the radial shrinkage and much greater than the longitudinal shrinkage for all tests. Poplar wood as a kind of cork, which has the highest volatile matter content among the four woods, showed the maximum final shrinkages. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Bubbly flow   Two-fluid equation   Reynolds-stress   Turbulence  

摘要： Two-fluid equations are widely used for practical applications involving multi-phase flows in chemical reactor, nuclear reactor, desalination systems, boilers, and internal combustion engines. The popular two-fluid equation for a gas-liquid two-phase flow is based on the assumption of interpenetrating continua. According to the experimental data of fully-developed turbulent bubbly flows in a horizontal pipe, the bubble phase velocity is close to or slightly smaller than the liquid phase velocity. The velocity profile is nearly symmetric along the vertical centerline of the horizontal pipe, or tends to be slightly skewed toward the bottom region of the pipe. However, numerical simulations using the momentum equation based on interpenetrating continua showed that, in contrast, the bubble phase was faster than the liquid phase. In addition, the velocity profile was predicted to be skewed toward the upper region of the pipe. These simulation results are not consistent with experimental observations. In the meantime, there are particle averaged momentum equations in which the continuous and disperse phase equations are developed from the equations of motions of fluid and particle, respectively. We considered two different particle averaged momentum equations. The form of one particle averaged momentum equation is similar to that of the momentum equation based on interpenetrating continua, except for the laminar viscosity term. Thus, for a turbulent bubbly flow, this particle averaged equation showed similar results as observed in the momentum equation based on interpenetrating continua. The other particle averaged equation differs from the momentum equation based on interpenetrating continua in both laminar and turbulent viscosity terms. This particle averaged equation showed good agreement with experimental observations. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： 流体包裹体   H-O-S同位素   山后金矿   胶东  

摘要： 通过对胶东山后金矿流体包裹体岩相学观察、显微测温和激光拉曼以及H-O-S同位素分析,研究了该矿床流体特征和物质来源。研究表明成矿流体早期为低盐度、低密度富CO_2的NaCl-H_2O-CO_2体系,之后由于沸腾作用逐渐演化成NaCl-H_2O体系,矿床形成温度为170~260℃,成矿深度为0.97~3.04km,属中浅成中低温热液金矿床;含矿石英中H-O同位素和硫化物S同位素共同指示,成矿流体早期以岩浆水(含变质水)为主,晚期混入大量大气降水,成矿物质主要来源于中生代燕山早期岩浆岩,古老变质岩亦有一定贡献;成矿机理主要是沸腾作用和大气降水的混合作用引起流体物理化学性质变化,流体还原性增强,在有利空间沉淀富集形成金矿床。

关键词： 水质量   氢键   表面张力   拉曼光谱  

摘要： 应用拉脱法和激光衍射法测定了蒸馏水、自来水和水库水的表面张力,并用激光拉曼光谱仪测定了它们的室温拉曼光谱。结果表明,水表面张力随温度升高而减小,相同温度下表面张力随水中杂质物含量增加而增大。水样品表面张力的差别源于水中所含杂质离子的种类和杂质离子的浓度以及不同荷电杂质离子与水分子的相互作用,弱化或破坏了水分子的氢键作用。拉脱法结果更接近于理论值,激光衍射法结果与理论值偏差相对较大。水拉曼散射说明水拉曼峰的相对强度、半高宽、拉曼频移、峰形对称性等都受水中溶解的杂质离子影响。水中富含的荷电离子产生的局域电场以及与水分子偶极作用产生的统计涨落导致的局域模效应引起的氢键变化影响水分子的振动,从而改变着水团簇结构,使水分子极化率降低,表现为拉曼散射的差异。

关键词： 微课   翻转课堂   大学物理  

摘要： 针对地方本科院校大学物理课程的教学现状和问题,结合"微课"和翻转课堂的特点,以"理想流体的伯努利方程"为例探讨了基于"微课"的翻转课堂教学模式在大学物理教学中的具体实践.

关键词： 秋树坪金矿   U-Pb定年   流体包裹体   氢氧同位素   造山型金矿  

摘要： 秋树坪金矿位于杨子地块北缘汉南-米仓山隆起的汉南推覆隆起带。在矿区内采集含金石英脉样品一件,运用ICP-MS U-Pb锆石测年方法,获得热液锆石的加权平均年龄为90.2 Ma±1.5 Ma,为金矿的成矿年龄。含金石英脉内继承锆石年龄为1 160 Ma±33 Ma,1 746 Ma±23 Ma,与基底火地垭群火山岩年龄相近。采集不同成矿阶段的含金石英脉样品6件,进行成矿流体特征研究。流体包裹体测温研究,获得秋树坪矿床成矿热液温度为205.06℃~444.9℃、盐度为2.88%~7.38%,密度为0.56g/cm3~0.87g/cm^3,具中-高温、低盐度、低密度特征。通过激光拉曼光谱分析,流体包裹体气相成分主要由CH_4,CO_2,H_2S,H_2和N_2组成,液相成分主要为H_2O,CH_4和CO_2;含金石英脉氢氧同位素分析,δ^(18)O_水变化范围为3.11‰~15.42‰,δD值为-62.4‰^-84.2‰,认为原始成矿热液为变质热液,后期混入大气降水,使δ^(18)O_水值大幅下降。结合成矿流体特征与陆陆碰撞造山运动的构造背景,认为秋树坪金矿为该地区首次厘定的燕山期造山型金矿。

关键词： calculation.   Vibration   coupling  

摘要： Brief description of research in nuclear engineering,the safety of reactor design is very *** structure inside the reactor and coolant constitute a complex fluid solid coupling system,so the flow induced vibration(FIV)is *** this paper,the specific influence of FIV,such as vibration amplitude,frequency,structural stablity,nonlinear dynamic characteristics,etc,and analysis and computational method for the influence of structural vibration damage are studied and *** the end,two methods of measuring the FIV and some strategies for vibration suppression design in the future development are summed *** cladding of fuel rod is regard as the first safety barrier in nuclear reactor,and it is important to do its life analysis and calculation.

关键词： 光敏   偶氮苯   表面活性剂   光异构化   表面张力   接触角  

摘要： 本文制备了一种含有偶氮苯基团的阴离子表面活性剂,其表面活性及对方解石矿物的润湿性能,可以用紫外光照射进行调控。在紫外光照射后,表面活性剂的临界胶束浓度(cmc)、最低表面张力(γcmc)、分子极限占有面积(Amin)增大,饱和吸附量(Гmax)和降低表面张力的效率(pC20)降低,对方解石的润湿能力增强。

关键词： 长输海底管道   水力计算   模型评价  

摘要： 依据典型水力计算模型的特点及适用范围进行研究和评价,对影响多相流压降的影响因素进行敏感性分析,对现场实测压降值与不同水力计算模型压降预测值进行对比分析。在此基础上,筛选出可以适用于天然气-凝析液长输海底管道水力计算的Eaton&Olieman和Oliemans Mechanistic模型。

关键词： 表面张力系数毛细管法低气压实验装置  

摘要： 表面张力是液体接触气体时的基本特性。设计了低气压下表面张力系数测量装置,研究了气压降低对水体表面张力系数的影响,提出了低气压下表面张力系数计算公式。研究表明,相同水体温度下,气压与水体表面张力系数间呈良好的线性关系;气压越低,表面张力系数越大。气压降低时,气压和温度对水体表面张力的影响是基本独立的。