滤嘴通风对加热卷烟气溶胶物理特性及其温度的影响

为研究滤嘴通风对加热卷烟气溶胶释放的影响,制备了滤嘴空腔段通风孔数量分别为0、2、4、6、8的1^(#)—5^(#)加热卷烟样品,分别采用微探针取样原位气溶胶表征方法和热电偶测温法考查了通风孔数量对气溶胶物理特性和温度的影响规律。结果表明:滤嘴通风改变了气溶胶的粒径分布,通风孔后气溶胶的粒数浓度和体积浓度随通风孔数量的增加呈降低趋势,5^(#)样品气溶胶体积浓度相较于1^(#)样品降低了57.4%,通风减小了气溶胶的粒数中值粒径,但其随通风孔数量的变化规律不显著;通风孔后气溶胶的温度随通风孔数量的增加呈降低趋势,5^(#)样品气溶胶温度相较于1^(#)样品降低了23.0℃;通风孔前、后气溶胶体积浓度与温度均呈现中轴线处高,且沿径向随距离增大逐渐降低的分布趋势。

溶胶温度、冷却温度对κ-卡拉胶凝胶微观形貌的影响

目的:研究溶胶温度、冷却温度对κ-卡拉胶微观形貌的影响,为实现加热型凝胶工艺的精准控制提供参考。方法:采用扫描电子显微镜对在不同溶胶温度与冷却温度下制备κ-卡拉胶凝胶进行形貌表征。结果:在80℃水浴温度下溶胶,随着冷却温度的降低,凝胶结构由无序堆叠形态向有序三维网状结构转变;温差过大时,凝胶微观结构易产生丝状物牵连。采用自然冷却工艺凝胶时,溶胶温度越高,凝胶三维网状结构越明显。在100℃水浴温度下溶胶,冷却温度对凝胶微观结构基本无影响。在90℃及以下水浴温度溶胶,凝胶受冷冻影响较大且会产生明显塌缩,不利于还原真实的凝胶形貌。结论:溶胶温度与冷却温度对κ-卡拉胶凝胶的微观形貌有明显影响。

温度对撞击器内颗粒沉积粒径影响的研究

微颗粒的性质几乎与颗粒的粒径紧密相关,为研究气溶胶粒子特性,需获取颗粒粒径分布信息.惯性撞击器是一种基于惯性原理实现大气中不同粒径颗粒沉积分离的装置,在实际使用过程中,经历复杂多变的环境.文章利用拉格朗日多相(LMP)模型对撞击器内的气-固两相流动进行数值模拟,使用有限体积方法(FVM)研究了在绝热和换热两种情况下,气溶胶温度变化(-40℃~60℃)对颗粒沉积率的作用,并分析其对颗粒粒径分离的影响.结果表明:在壁面绝热情况下,随着气溶胶温度的升高,颗粒沉积位置由冲击板中心向边缘发散,颗粒收集效率逐渐降低,颗粒收集数量减少;在气溶胶和壁面换热情况下,随着气溶胶温度的升高,大颗粒沉积位置由冲击板中心向边缘发散,颗粒收集效率降低,小颗粒正好相反.此外,不同气溶胶温度下的颗粒收集效率曲线存在一个交点,交点两侧大小颗粒的收集效率随温度的变化情况相反.通过研究温度对撞击器颗粒收集的影响,可以对颗粒分径结果进行修正,获得更精确的粒径分布.

温度对碳热还原合成SiC晶须的影响

以工业硅溶胶和碳黑为主要原料，用溶胶—凝胶和碳热还原法进行了合成ＳｉＣ晶须的试验，探讨了合成温度对产物组成微观形貌的影响。结果表明：合成ＳｉＣ晶须适合的温度为１６００℃，在此条件下得到的产物中ＳｉＣ 晶须含量最高（７４％以上）、质量最好。

载锰飞灰吸附剂脱除SO2的实验研究

采用溶胶凝胶法制备脱除SO2用载锰飞灰吸附剂,并借助固定床评价系统对其脱硫性能进行测试。实验结果表明,吸附剂WNa(2)5Br Mn(3)100具有最高的脱硫能力,其本质原因是:NaBr在飞灰水化过程可以增强NaOH对飞灰表面玻璃体的破坏,生成水溶性胶体Na2SiO3,利用具有氧化性的Mn组分负载,Mn与Na2SiO3的共同作用可以显著增强吸附剂的脱硫性能,NaOH和Mn(NO3)2存在最佳添加量;溶胶温度会通过影响吸附剂的晶体结构来影响吸附剂的脱硫性能,溶胶温度越高其脱硫能力越强,最佳溶胶温度为100℃;飞灰吸附剂的粒径会通过影响其孔结构参数而影响对SO2的脱除能力,本实验中最佳粒径范围为270~150mm;根据载锰飞灰吸附剂自身特性,可用研磨溶胶的方法使其再生。

羧基化碳纳米管增强的杂化超分子水凝胶及其物理性能

通过物理交联方法制备了含羧基化碳纳米管(CNTs-COOH)的杂化超分子水凝胶,采用透射电子显微镜(TEM)观察样品的微观形貌,探究了碳纳米管的引入对凝胶的溶胀性、凝胶-溶胶转变温度和力学性能的影响。结果显示,与初始纯凝胶相比,质量分数2.5%的碳纳米管的引入不但没有改变凝胶的初始形貌和微观结构,反而提高了其凝胶-溶胶转变温度,且凝胶的力学性能也明显得到增强。进一步研究表明,制备的杂化水凝胶依然具有超分子水凝胶的基本特性,特别是剪切变稀、温度响应性和自恢复特性。

脱氢松香基有机小分子凝胶因子的合成及其性能

用12-溴-13,14-双硝基脱氢松香酸甲酯合成了一种新型的有机小分子凝胶因子1,4a-二甲基-6-溴-1,2,3,4,4a,17,18,18a-八氢萘基[2,1-h]二吡啶并[3,2-a:2,3-c]吩嗪甲酸甲酯(DBNPM),通过1H NMR,13C NMR,MS和IR等表征手段对产物结构进行了表征。为了考察此小分子凝胶因子的自组装行为,研究了该分子在不同有机溶剂中的成胶性能和形貌。研究发现,在甲醇中临界成胶浓度(CGC)最低,为0.5 g/L;但是在二氧六环中凝胶性质最为稳定。扫描电镜(SEM)照片显示,从甲醇溶剂中得到的干胶呈片状结构,从二氧六环溶剂中得到的干胶呈网状结构;通过红外光谱和XRD测试研究证实,该化合物分子间的氢键是凝胶化的重要驱动力之一。

Crystallization Behavior and Properties of B-Doped ZnO Thin Films Prepared by Sol-Gel Method with Different Pyrolysis Temperatures

Boron-doped zinc oxide transparent （BZO） films were prepared by sol-gel method. The effect of pyrolysis temperature on the crystallization behavior and properties was systematically investigated. XRD patterns revealed that the BZO films had wurtzite structure with a preferential growth orientation along the c-axis. With the increase of pyrolysis temperature, the particle size and surface roughness of the BZO films increased, suggesting that pyrolysis temperature is the critical factor for determining the crystallization behavior of the BZO films. Moreover, the carrier concentration and the carrier mobility increased with increasing the pyrolysis temperature, and the mean transmittance for every film is over 90% in the visible range.

Assessment of aerosol effective radiative forcing and surface air temperature response over eastern China in CMIP5 models

The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model results show that, relative to 1850, the multi-model and annual mean aerosol ERF for the year 2005 is -4.14 W m^-2 at the top of the atmosphere over eastern China （20°-45°N, 105°-122.5°E）. As a result of this ERF, the multi-model and annual mean surface air temperature change in eastern China during 1850-2005 is -1.05℃, leading to a climate sensitivity of 0.24℃/ （Wm^-2） in this region.

Role of Black Carbon-Induced Changes in Snow Albedo in Predictions of Temperature and Precipitation during a Snowstorm

In this study the authors apply the chemistry version of the Weather Research and Forecasting model （WRF-Chem） to examine the impacts of black carbon （BC）-induced changes in snow albedo on simulated temperature and precipitation during the severe snowstorm that occurred in southern China during 0800 26 January to 0800 29 January 2008 （Note that all times are local time except when otherwise stated）. Black carbon aerosol was simulated online within the WRF-Chem. The model resuits showed that surface-albedo, averaged over 27-28 January, can be reduced by up to 10% by the deposition of BC. As a result, relative to a simulation that does not consider deposition of BC on snow/ice, the authors predicted surface air temperatures during 27-28 January can differ by -1.95 to 2.70 K, and the authors predicted accumulated precipitation over 27-28 January can differ by -2.91 to 3.10 mm over Areas A and B with large BC deposition. Different signs of changes are determined by the feedback of clouds and by the availability of water vapor in the atmosphere.

The Different Effects of Sea Surface Temperature and Aerosols on Climate in East Asia During Spring

In this study, we used the NCAR CAM3.0 model to study the climate effects of both decadal global Sea Surface Temperature(SST) changing and the increasing aerosol concentration in East Asia in boreal spring. In the decadal SST changing experiment, a prominent sea surface cyclone anomaly occurred west of the Northwest Pacific warming SST. The cyclone anomaly is conductive to anomalous rising motion and more rainfall over the Northwest Pacific and southeast coast areas of China, but less rainfall in central China. Caused by the only aerosol concentration increasing, the change of climate in East Asia is totally different from that induced by the regime shift of SST around 1976/77 with the same model. The sulfate and black carbon aerosol concentrations were doubled respectively and synchronously in East Asia(20?–50?N, 100?–150?E) to investigate the climate effects of these two major aerosol types in three experiments. The results show that, in all three aerosol concentration changing experiments, the rainfall during boreal spring increases in North China and decreases in central China. It's worth noting that in the DTWO experiment, the rainfall diminishes in central China while it increases in the north and southeast coast areas of China, which is similar to observations. From the vertical profile between 110?E and 120?E, it is found that sulfate and black carbon aerosols first change the temperature of lower troposphere owing to their direct radiative effect, and then induce secondary meridional circulation anomaly through the different dynamic mechanisms involved, and at last generate precipitation and surface temperature anomalous patterns mentioned above.

Synthesis and Conductivity of Oxyapatite Ionic Conductor La10-xVx（SiO4）6O3＋x

Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and the influences of V-dopant content on calcining temperature and conductivity were reported.The samples were characterized by thermal analysis(TG-DSC) ,X-ray diffraction(XRD) and scanning electron micrograph(SEM) . The apatite was obtained at 800°C,a relatively low temperature in comparison to 1500°C with the conventional solid-state method.The ceramic pellets sintered at 1200°C for 5 h showed a higher relative density than La9.33Si6O26 pellets sintered at 1400°C for 20 h.The conductivities of samples were measured by electrochemical impedance spectroscopy.The conductivity was improved with the increase of V-dopant content on La site.

Experimental assessment of a new salt aerosol generator for measuring efficiency of automotive air filters

Generation of polydisperse KCl aerosol with a new salt aerosol generator was investigated, Special attention was paid on particles with diameters between 3 and 10 μm. The main improvement consists of the different routes of KCl solution droplets. In traditional generators, the solution droplets travel through one cylinder; while in the case analyzed here, after spray atomization, the droplets travel through two cylinders in series. The first cylinder was fed with warm air and the second one with cold air. In such way, the complete evaporation of the water from the droplets can be ensured. The influencing factors of the generated aerosol size distribution were investigated. The data measured show that the concentration of generated aerosol becomes higher both increasing the flow rate of the KCI solution injected in the first cylinder and increasing the concentration in the solution. The temperature of solution influences mainly the generation of smaller KCI particles （0,3-3 μm）. The amount of hot air used in the generation process increases the concentration of larger KC1 particles （〉3 μm） while cold air does not have the same effect. The aerosol generator is able to generate KC1 aerosol stably. This instrument can be used effectively for testing air filters for automotive.

Preparation of Composite Phase Change Material Based on Sol-Gel Method and Its Temperature-Adjustable Textile

In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.

中性果冻质构影响因素及配方工艺

以中性果冻为研究对象,通过物性测定仪测定凝胶硬度、咀嚼度、脆度,分别考察刺槐豆胶、氯化钾、溶胶温度对凝胶果冻质构的影响。中性果冻最佳配方为刺槐豆胶添加量0.20%、氯化钾添加量0.10%、溶胶温度80℃。试制产品软硬适中,口感滑爽。

Lower temperature synthesis of cerium-doped polycrystalline lutetium pyrosilicate powders by a novel sol-gel processing

A novel sol-gel processing was developed to synthesize polycrystalline cerium-doped lutetium pyrosilicate （Lu2Si2O7Ce, LPS ：Ce） powders under low temperature. It was found that the addition of propylene oxide （PPO） could promote the formation of Lu-O-Si bonds in precursor, which was beneficial to the formation of LPS phase. X-ray diffraction （XRD） patterns indicated that the single-phased LPS powder was well crystallized at 1050℃. Microstructure observation demonstrated that the synthetic LPS powder was composed of ellipsoidal grains with the mean size of 40 nm. The luminescent properties were characterized by photoluminescence （PL）, X-ray excited luminescence （XEL） and vacuum ultraviolet （VUV） spectroscopy at room temperature. The synthetic LPS：Ce powder emitted a broad emission spectrum centered at about 380 nm, which should be ascribed to the 5d→4f transition of Ce3＋. Decay time of the synthetic LPS：Ce powder was measured to be only 32 ns.

Novel sol-gel material for fabrication of a long period waveguide grating filter as a precise thermometer

A new kind of organic-inorganic hybrid HfO2/SiO2 sol-gel material with a large thermo-optic coefficient and a wide linear tunable temperature range has been developed for fabrication of a long period waveguide grating （LPWG） filter, whose parameters were optimized and designed by using finite difference time domain （FDTD） simulations. The LPWG filter, a periodic rectangle-corrugated grating structure, was easily fabricated with soft-lithography technique. At a temperature range from 19~C to 70~C, the fabricated LPWG filter element demonstrated a high temperature sensitivity of about 6.5 nm/~C and a wide linear tunable temperature range of 51℃, so that it can be used as a precise thermometer. Our results are useful for the designs of LPWG filters for the implementation of a wide range of thermo-optic functions.

Aerosol-assisted rapid synthesis of SnS-C composite microspheres as anode material for Na-ion batteries

SnS-C composite powders were prepared through one-pot spray pyrolysis for use as anode materials for Na-ion batteries. C microspheres with uniformly attached cubic-like SnS nanocrystals, which have an amorphous C coating layer, were formed at a preparation temperature of 900 ℃. The initial discharge capacities of the bare SnS and SnS-C composite powders at a current density of 500 mA·g^-1 were 695 and 740 mA·h·g^-1, respectively. The discharge capacities after 50 cycles and the capacity retentions measured from the second cycle of the bare SnS and SnS-C composite powders were 25 and 433 mA.h.g-1 and 5 and 89%, respectively. The prepared SnS-C composite powders with high reversible capacities and good cycle performance can be used as Na-ion battery anode materials.

Numerical simulation study of temperature change over East China in the past millennium

Despite many studies on reconstructing the climate changes over the last millennium in China,the cause of the China's climate change remains unclear.We used the UVic Earth System Climate Model(UVic Model),an Earth system model of intermediate complexity,to investigate the contributions of climate forcings(e.g.solar insolation variability,anomalous volcanic aerosols,greenhouse gas,solar orbital change,land cover changes,and anthropogenic sulfate aerosols) to surface air temperature over East China in the past millennium.The simulation of the UVic Model could reproduce the three main characteristic periods(e.g.the Medieval Warm Period(MWP),the Little Ice Age(LIA),and the 20th Century Warming Period(20CWP)) of the northern hemisphere and East China,which were consistent with the corresponding reconstructed air temperatures at century scales.The simulation result reflected that the air temperature anomalies of East China were larger than those of the global air temperature during the MWP and the first half of 20CWP and were lower than those during the LIA.The surface air temperature of East China over the past millennium has been divided into three periods in the MWP,four in the LIA,and one in the 20CWP.The MWP of East China was caused primarily by solar insolation and secondarily by volcanic aerosols.The variation of the LIA was dominated by the individual sizes of the contribution of solar insolation variability,greenhouse gas,and volcano aerosols.Greenhouse gas and volcano aerosols were the main forcings of the third and fourth periods of the LIA,respectively.We examined the nonlinear responses among the natural and anthropogenic forcings in terms of surface air temperature over East China.The nonlinear responses between the solar orbit change and anomalous volcano aerosols and those between the greenhouse gases and land cover change(or anthropogenic sulfate aerosols) all contributed approximately 0.2℃ by the end of 20th century.However,the output of the energy-moisture balance atmospheric model from UVic showed no obvious nonlinear responses between anthropogenic and natural forcings.The nonlinear responses among all the climate forcings(both anthropogenic and natural forcings) contributed to a temperature increase of approximately 0.27℃ at the end of the 20th century,accounting for approximately half of the warming during this period;the remainder was due to the climate forcings themselves.