钙基二氧化碳吸收剂循环反应特性

对分析纯碳酸钙和三种白云石与CO2的循环反应特性进行实验研究。实验结果表明,分析纯碳酸钙的二氧化碳吸收能力随循环次数的增加而快速下降,当其达到一定值后基本不再变化,活性下降原因主要是由氧化钙烧结所引起;由于白云石中惰性物质氧化镁的存在而部分减缓了吸收剂的烧结,所以使白云石的循环稳定性要优于分析纯碳酸钙。

基于微流控的二氧化硅复合海藻酸钙空心微纤维制备

针对海藻酸钙水凝胶空心纤维拉伸性能较差、应用受到限制的缺点,通过添加二氧化硅形成纳米复合水凝胶来提高其拉伸性能。研究发现,随着添加二氧化硅浓度的增加,水凝胶的拉伸性能呈现先增加再降低的趋势,其饱和浓度为3%。此时,凝胶的拉伸强度达到最大值,为444 k Pa。与未添加二氧化硅的凝胶相比,拉伸强度和断裂伸长率分别提高了600%和23%。采用该条件通过微流控方法一步制备了二氧化硅纳米复合水凝胶的中空微纤维,应用光学显微镜和扫描电子显微镜对其空心结构进行了表征。同时应用傅立叶变换红外光谱对其分子结构进行了分析。最后,考察了编织方法对凝胶纤维拉伸性能改善的效果。

CaF_2对硅质耐火材料的侵蚀

通过含CaF2 的颜色玻璃对硅质耐火材料侵蚀的研究及微观结构分析 ,认为 :由于颜色玻璃中CaF2 的引入 ,使玻璃中的Na2 O挥发增加 ,加快了硅砖的侵蚀 ;Na2 O是促使硅砖晶相转变的矿化剂 ,使硅砖内晶相发生重结晶和多晶转变并伴随体积变化 ,引起砖硅的组成、结构、使用性能的变化。CaF2 的引入 。

Secondary reaction mechanism of leaching process of calcium aluminate slag

SiO2 in calcium aluminate slag exists in the form of γ-2CaO·SiO2 which is more stable than β-2CaO·SiO2. However, it is decomposed by sodium carbonate solution during leaching process, leading to the secondary reaction. The extent of secondary reaction and reaction mechanism of calcium aluminate slag were studied using XRD. The results show that the decomposition rate of γ-2CaO·SiO2 increases with the increase in leaching time and sodium carbonate concentration. The main products of secondary reaction are the mixture of hydrogarnet and sodium hydrate alumina-silicate. SiO2 concentration rises firstly and then drops with the increase of leaching temperature. XRD results indicate that the stable product of secondary reaction at low temperature is hydrogarnet. But hydrogarnet is transformed into sodium hydrate alumina-silicate at high temperature.

单片防火玻璃生产过程中个人保护及安装方法

单片防火玻璃有两种，一种是铯钾防火玻璃，另一种是钠钙防火玻璃，这两种玻璃各有所长，铯钾防火玻璃的特点是强度高，耐火度高，生产灵活方便。钠钙防火玻璃则是生产原片玻璃之前，混料的时候加入二氧化钙而成的。这种玻璃生产厂家少，原片玻璃透光率低，网状结构像陶瓷，耐火温度高，冲击强度小，大规模玻璃生产困难，切割成品率低，所以在建筑材料市场中还是主要以铯钾防火玻璃为主，但是目前市场比较混乱，许多安装施工人员对此缺乏了解，令人担忧，为此，本文将从单片防火玻璃生产过程中个人保护及安装方法向大家做一阐述。

Carbon Dioxide Captured from Flue Gas by Modified Ca-based Sorbents in Fixed-bed Reactor at High Temperature

Four kinds of Ca-based sorbents were prepared by calcination and hydration reactions using different precursors： calcium hydroxide, calcium carbonate, calcium acetate monohydrate and calcium oxide. The CO2 absorption capacity of those sorbents was investigated in a fixed-bed reactor in the temperature range of 350-650 ℃. It was found that all of those sorbents showed higher capacity for CO2 absorption when the operating temperature higher than 450 ℃. The CaAc2-CaO sorbent showed the highest CO2 absorption capacity of 299 mg.g-1. The mor- phology of those sorbents was examined by scanning electron microscope （SEM）, and the changes of composition before and after carbonation were also determined by X-ray diffraction （XRD）. Results indicated that those sorbents have the similar chemical compositions and crystalline phases before carbonation reaction [mainly Ca（OH）2], and CaCO3 is the main component after carbonation reaction. The SEM morphology shows clearly that the sorbent pores were filled with reaction products after carbonation reaction, and became much denser than before. The N2 adsorption-desorption isotherms indicated that the CaAc2-CaO and CaCO3-CaO sorbents have higher specific surface area. lar2er oore volume and anoropriate pore size distribution than that of CaO-CaO and Ca（OH）2-CaO.

Fabrication of A Folic Acid-Modified Arsenic Trioxide Prodrug Liposome and Assessment of its Anti-Hepatocellular Carcinoma Activity

Objective To reduce the toxicity and side effects of arsenic trioxide(ATO)and provide a new approach for the treatment of primary liver cancer,a folic acid-modified calcium arsenite liposomal“target-controlled”drug delivery system(FA-LP-CaAs)was fabricated using the reverse microemulsion method.Methods A Malvern particle size analyzer and a transmission electron microscope were employed to determine the particle size,distribution,zeta potential and morphology of FA-LP-CaAs.Further,inductively coupled plasma emission spectrometry was employed to determine the drug loading capacity,entrapment efficiency,and in vitro release behavior of FA-LP-CaAs.To determine its toxicity in human hepatoma cells(HepG2)and human normal hepatocytes(LO2)and its effect on HepG2 cell cycle and apoptosis,the MTT method was used.Laser confocal and flow cytometry were also employed to determine the uptake of FA-LP-CaAs by cells.After establishing a mouse liver cancer model,the in vivo distribution of the drug included in the formulation was investigated using in vivo fluorescence.To evaluate the liver cancer targeting and anti-tumor effects of FALP-CaAs in vivo,the distribution of ATO in tissues and changes in tumor volume and body weight after liposomal administration were investigated using hematoxylin-eosin(HE)-stained tumor sections.Results The particle size,zeta potential and PDI of FA-LP-CaAs were(122.67±2.18)nm,(12.81±0.75)mV and 0.22±0.01,respectively,while its drug loading capacity was 18.49%±1.14%.In vitro experimental results revealed that FA-LP-CaAs had a strong killing effect on HepG2 cells.Further,the cell uptake capacity of this formulation was found to improve.Based on in vivo assessments,FA-LP-CaAs could significantly increase the distribution of ATO in tumor sites and inhibit tumor growth.Conclusions Herein,an FA-LP-CaAs formulation was successfully fabricated.This liposomal drug delivery system had a round appearance,uniform particle size,good polydispersity coefficient,evident“core-shell”structure,high drug loading capacity and pH response,tumor targeted drug delivery and sustained drug release.These findings support further research and the application of ATO as an anti-liver cancer prodrug and provide a new method for the treatment of liver cancer.

Comparative analysis of hydrogen-producing bacteria and its immobilized cells for characteristics of hydrogen production

A strain of hydrogen producing bacteria was immobilized by polyvinyl alcohol-boric acid method, with the addition of a small amount of calcium alginate. The immobilized cells were insensitive to the presence of traces of O2. Moreover, the immobilized cells increased both the evolution rate and the yield of hydrogen production. Batch experiments with a medium containing 10 g/L glucose demonstrated the yields of hydrogen production by the immobilized and free cells were 2.14 mol/mol glucose and 1.69 mol/mol glucose, respectively. In continuous cultures at medium retention time of 2.0 h, the yield and the evolution rate of hydrogen production by the immobilized cells were 2.31 mol/mol glucose and 1 435.4 ml/（L·h） respectively. However, at medium retention time of 6.0 h, the yield and the evolution rate of hydrogen production by free cells were only 1.75 mol/mol glucose and 362.9 ml/（L·h）, respectively.

Calcium Carbonate Lab Scale Continuous Carbon Dioxide-jet Controlled Production Following Fuzzy Logic Model

In this paper, lab scale production carried out of calcium carbonate in 400 mL open cylindrical beaker reactor following fuzzy logic approach is reported. 10 grams of Calcium hydroxide is mixed in 250 mL deionized water. Continuous jet supply of carbon dioxide is maintained at controlled flow rate. Reaction histories are noted for different reaction temperatures. Continuous constant magnetic stirring is applied to maintain homogeneity. The data obtained is fuzzified by constructing universe of discourse of temperature, reaction time, and amounts of reactants with reaction conversion. Rule based model is tabulated and results show that fuzzy logic approach is promising to set on data to plan and scale up the process. It is also found that a jump can not be made at this time with few studies of fuzzy logic applications to physiochemical processes unless otherwise amassing and storing up plentiful deduced explorations.

Study on structural and compositional transitions of coal ash by using NMR

Structural and compositional transitions of Datong coal ash and its CaCO3 additional effects were carefully exam- ined at a temperature range of 300 to 1 600℃ by using XRD and solid state NMR. The quantitative estimation of amorphous structures of ashes can be successfully obtained through the analyses of solid state NMR spectra. Viscosity of molten ash and its changes with CaCO3 addition were also evaluated up to 1 700 ℃ by using a rotary type viscometer. Glasses with poor crystalline and amorphous phase were continuously formed through the eutectic reaction of silica above fusing temperature （FT〉1 500 ℃） that caused broadening and shift of 29Si and 27A1 peaks in NMR results. With the additional amount of CaCO3 increasing, the peaks shifted to downfield obviously; the fraction of Si（OA1）0（OSi）4 decreased, while that of Si（OA1）l（OSi）l at 84.3 x 10-6 increased apparently. These transitions indicated the destruction of large alumina-silicate framework into small segments by the addition of Ca ion.

Experiment and simulation of foaming injection molding of polypropylene/nano-calcium carbonate composites by supercritical carbon dioxide

Microcellular injection molding of neat isotactic polypropylene(iPP) and isotactic polypropylene/nano-calcium carbonate composites(i PP/nano-CaCO_3) was performed using supercritical carbon dioxide as the physical blowing agent. The influences of filler content and operating conditions on microstructure morphology of i PP and i PP/nano-CaCO_3 microcellular samples were studied systematically. The results showed the bubble size of the microcellular samples could be effectively decreased while the cell density increased for i PP/nano-CaCO_3 composites, especially at high CO_2 concentration and back pressure, low mold temperature and injection speed, and high filler content. Then Moldex 3D was applied to simulate the microcellular injection molding process, with the application of the measured ScCO_2 solubility and diffusion data for i PP and i PP/nano-Ca CO_3 composites respectively. For neat i PP, the simulated bubble size and density distribution in the center section of tensile bars showed a good agreement with the experimental values. However, for i PP/nano-CaCO_3 composites, the correction factor for nucleation activation energy F and the pre-exponential factor of nucleation rate f_0 were obtained by nonlinear regression on the experimental bubble size and density distribution. The parameters F and f_0 can be used to predict the microcellular injection molding process for i PP/nano-CaCO_3 composites by Moldex 3D.

Enhanced photocatalytic CO_(2)reduction performance in Nidoped perovskite nanocrystals controlled by magnetic fields

In recent years,magnetic fields have been widely applied in catalysis to increase the performance of electrocatalysis,photocatalysis,and thermocatalysis through an important noncontact way.This work demonstrated that doping CsPbCl_(3) halide perovskite nanocrystals with nickel ions(Ni2+)and applying an external magnetic field can significantly enhance the performance of the photocatalytic carbon dioxide reduction reaction(CO_(2)RR).Compared with its counterpart,Ni-doped CsPbCl_(3) exhibits a sixfold increase in CO_(2)RR efficiency under a 500 mT magnetic field.Insights into the mechanism of this enhancement effect were obtained through photogenerated current density measurements and X-ray magnetic circular dichroism.The results illustrate that the significant enhancement in catalytic performance by the magnetic field is attributed to the synergistic effects of magnetic element doping and the external magnetic field,leading to reduced electron‒hole recombination and extended carrier lifetimes.This study provides an effective strategy for enhancing the efficiency of the photocatalytic CO_(2)RR by manipulating spin-polarized electrons in photocatalytic semiconductors via a noncontact external magnetic field.

激光熔覆Al_2O_3/CaF_2陶瓷基高温自润滑耐磨复合材料涂层组织与耐磨性研究

航空航天、热能、电力工业装备中许多在高温腐蚀性气氛条件下工作的摩擦运动副零部件,不仅要求材料具有优异的高温耐磨性与抗氧化性,同时由于高温条件下无法实现外加润滑而必须具有优异的高温自润滑性能。采用先进的表面工程手段在高温结构材料工件表面制备具有优良高温自润滑性能的先进氧化物陶瓷基高温自润滑耐磨复合材料涂层,是解决上述问题的有效方法之一。本文采用激光熔覆技术上制备出了以氧化物陶瓷Al_2O_3为基、以CaF_2为高温自润滑相的陶瓷基高温自润滑耐磨复合材料涂层,在干滑动磨损试验条件下测试了涂层的耐磨性能。结果表明,激光熔覆Al_2O_3/CaF_2陶瓷基高温自润滑耐磨复合材料中,具有优异高温耐磨性能及高温稳定性的Al_2O_3以片状初生相形式析出形成连续的基体骨架、而具有优异高温自润滑性能的CaF_2则呈球状均匀分布于基体骨架中之间;摩擦磨损试验结果表明,由于激光熔覆Al_2O_3/CaF_2陶瓷基高温自润滑耐磨复合材料集中了Al_2O_3先进氧化物陶瓷材料优异的高温耐磨性、高温抗氧化性及CaF_2高温自润滑相的优异高温自润滑性能,激光熔覆Al_2O_3/CaF_2陶瓷基高温自润滑耐磨复合材料涂层具有优异的摩擦学性能,同激光熔覆Al_2O_3陶瓷涂层相比,激光熔覆Al_2O_3/CaF_2陶瓷基高温自润滑耐磨复合材料?

Two centuries-long records of skeletal calcification in massive Porites colonies from Meiji Reef in the southern South China Sea and its responses to atmospheric CO_2 and seawater temperature

Rising atmospheric CO2 and warming of the global climate that have occurred since the industrial revolution are regarded as fatal threats to coral reefs. We analyzed the skeletal calcification rate of 14 massive Porites corals from the Meiji Reef in the southern South China Sea through X-ray photography of coral skeletons. A general pattern of change in coral skeletal calcifi- cation was determined. The change pattern of coral calcification on the Meiji Reef over the past two centuries can be divided into five periods： calcification increase in 1770-1830, 1870-1920, and 1980-2000 and calcification decline in 1830-1870 and 1920-1980. Over the past two centuries, the largest increase in calcification was 4.5%, occurring in 1770-1830, whereas the largest decline in calcification was 6.2%, occurring in 1920-1980. Coral calcification slightly increased in the recent 20 years （1980-2000）. The response relationship of coral calcification to atmospheric CO2 and sea surface temperature （SST） shows that calcification was not correlated with atmospheric CO2 but responded nonlinearly to SST with maxima at ~27.2~C in 1900-2000. On the Meiji Reef, increasing atmospheric CO2 had a negligible effect on coral growth in the past century. How- ever, rising SST improved coral growth in the early and middle 20th century, and restricted coral growth in the recent 20 years.