载体用多孔Na_2O-TiO_2-P_2O_5-CaO微晶玻璃的研制

介绍了应用过析晶(post crystallization)热处理工艺制备多孔Na2O TiO2 P2O5 CaO微晶玻璃的方法.运用XRD探讨了该玻璃在过析晶热处理中晶相的演变过程,阐述了孔径扩大的机理.用SEM和密度法研究了过析晶热处理对孔径尺寸和气孔率大小的影响.由于连通孔的特征和孔径可控的特点,该类多孔微晶玻璃有可能作为生物、药物载体而得到应用.     

CaO—Al2O3—SiO2系统粉煤灰玻璃的烧结和晶化性能研究

用烧结法制备了一种CaO-Al2O3-SiO2系统粉灰微晶玻璃；研究了CaO,AlO3、SiO2、S等成分对玻璃颗粒的烧结和晶化性能的影响；探讨了热处理过程中烧结与晶经的相互关系。结果表明，以表面核化析晶为主的玻璃比以整体核化析晶为主的玻璃更适合于颗粒烧结法。     

R_2O-CaO-SiO_2-F系统微晶玻璃的研究和制备

通过整体析晶法制备R_2O-CaO-SiO_2-F系统微晶玻璃并在制备过程中研究成分配比、制备方法,氟含量的改变对微晶玻璃分相的影响、分相对成核和析晶的影响以及R_2O-CaO-SiO_2-F系统微晶玻璃合理的热处理制度,为大规模工业化生产提供一定的理论依据。     

用高岭土尾矿研制CaO—Al2O3—SiO2—K2O—Na2O微晶玻璃装饰板

作者以ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２－Ｋ２Ｏ－Ｎａ２Ｏ系统为基础成分，利用高岭土尾矿等原料研制出性能优良的微晶玻璃装饰板材。并研究和讨论影响微晶玻璃装饰板材烧结和析晶性能的因素。     

压电微晶玻璃定向析晶工艺研究

本文研究了BSTS压电微晶玻璃的定向析晶工艺,分析了热处理温度,温度梯度、及保温时间对析晶性能的影响,探讨了BSTS压电微晶玻璃的定向析晶机理。     

钽铌尾矿微晶玻璃的研究

以钽铌尾矿、氧化钙、无水碳酸钠为主要原料，不加晶核剂，采用碎粒压延法(又称颗粒熔体混合法)研制出钽铌尾矿微晶玻璃。利用DTA、XRD研究该微晶玻璃的析晶性能和主晶相等，利用SEM研究微晶玻璃的显微结构，同时研究配合料组成和热处理制度对核化、析晶的影响，结果表明：最佳核化温度为600～700℃，晶化温度为750～900℃。     

差热分析在微晶玻璃晶化工艺中的应用

介绍了利用差热分析测定玻璃的析晶活化能及确定晶化最佳热处理工艺的方法，结果表明用差热分析确定微晶玻璃的晶化工艺是一种行之有效的方法。     

新工艺制备矿渣微晶玻璃初探

目前制备矿渣微晶玻璃的方法主要有压延法、浇注法和烧结法,在充分吸收浇注法和烧结法优点的基础上,提出一种制备矿渣微晶玻璃的新工艺.并以钽铌尾矿为主要原料,基础玻璃组成选择在CaO-Al2O3-SiO2系统的玻璃形成区内,利用DTA、XRD和SEM等测试办法研究了热处理工艺制度对晶化过程、晶相组成、显微结构的影响.结果表明,采用新工艺制备微晶玻璃在实验室是可行的,热处理工艺制度的变化会影响玻璃的析晶转变过程和微晶玻璃的微观结构.     

晶核剂P2O5对Li2O-ZnO-SiO2微晶玻璃析晶性能的影响

应用DSC（差热分析）、X-射线衍射、SEM（扫描电镜）等分析手段,研究了晶核剂P2O5含量对Li2O-ZnO-SiO2系玻璃析晶的影响。结果表明,在所研究的微晶玻璃体系中,析出晶相为方石英、磷石英以及少量的Li2O-ZnO-SiO2和Si02相。晶核剂P2O5的加入促进了玻璃中方石英晶体的析出,当P2O5添加量增加到4．0％时,该体系玻璃中析出的方石英相对含量达到最高。当进一步提高P2O5的含量达到5．1％时,促进了玻璃在低温下的析晶,基础玻璃在535℃的较低温度下可以析出晶体。     

Al2O3对MgO-ZnO-SiO2系微晶玻璃显微结构的影响

通过差热分析(DTA)、X-射线衍射(XRD)测试方法,着重讨论了Al2O3对MgO-ZnO-SiO2系微晶玻璃显微结构的影响.通过梯温炉测试,了解了该系统的析晶性能.     

Production of H2O2 in hydrocarbon-O2-CF3Br systems

Hydrogen peroxide is produced when CF₃Br is added to flowing hydrocarbon-oxygen mixtures at approximately 350 °C. The H₂O₂ concentration is dependent on the amount of CF₃Br added to the hydrocarbon-oxygen mixture and maximizes at approximately 40 mole% CF₃Br.     

Greywater treatment by UVC/H2O2

Greywater treatment by UVC/H₂O₂ was investigated with regard to the removal of chemical oxygen demand (COD). A COD reduction from 225 to 30 mg l⁻¹ (overall removal of 87%) was achieved after settling overnight and subsequent irradiation for 3 h with 10 mM H₂O₂. Most of the contaminants were removed by oxidation since only 13% COD was removed by settlement.The removal of COD in the greywater followed a second-order kinetic equation, r = 0.0637[COD][H₂O₂], up to 10 mM H₂O₂. A slightly enhanced COD removal was observed at the initial pH of 10 compared with pH 3 and 7. This was attributed to the dissociation of H₂O₂ to O₂H⁻. The treatment was not affected by total concentration of carbonate (c_T) of at least 3 mM, above which operation between pH 3 and 5 was essential. The initial biodegradability of the settled greywater (as BOD₅:COD) was 0.22. After 2 h UVC/H₂O₂ treatment, a higher proportion of the residual contaminants was biodegradable (BOD₅:COD = 0.41) which indicated its potential as a pre-treatment for a biological process.     

X射线荧光光谱法测定电解铝灰中SiO2、Fe2O3、MgO、CaO、K2O、Na2O、MnO、TiO2、P2O5的含量

电解铝灰、铝渣是铝在电解过程中产生的一种浮渣,电解过程中漂浮在电解槽铝液的上方,主要成分为电解过程中未反应的冰晶石、氧化铝、金属铝等混合物,回收价值较高。对电解铝灰的成分分析,相对于化学滴定等分析方法,X射线荧光光谱法样品前处理更加简单方便,且可以同时对多组分进行分析。用粉末压片-X射线荧光光谱法测定电解铝灰中SiO₂、Fe₂O₃、MgO、CaO、K₂O、Na₂O、MnO、TiO₂、P₂O₅的含量。以成分含量相近的铝土矿国家标准物质样品绘制具有一定浓度梯度的标准曲线,通过理论α系数校正方法和经验校正法校正。所得结果表明:各元素含量在标准工作曲线中标准样品的含量范围内时,测定结果和常规分析方法测定结果相符。在方法的精密度实验中,含量较高的SiO₂的极差为0.2%,其他元素值也较为稳定,满足质量要求。     

Ti/SnO2,Ti/SnO2-Sb2O3阳极电催化氧化酸性品红的试验研究

采用热氧化法制备了Ti/SnO2和Ti/SnO2-Sb2 O3电极,以酸性品红为研究对象,对两种电极材料进行了性能比较,考察槽电压、电流密度、电解质浓度对电催化氧化处理系统的影响.结果表明:热氧化法制备出的Ti/SnO2-Sb2 O3电极,其电催化性能明显优于Ti/SnO2电极;以Ti/SnO2-Sb2 O3为阳极,在酸性品红初始浓度为100 mg/L、电极间距为2.5 cm、电流密度为75mA/cm2、电解质浓度取12 g Na2SO4/L时,60 min后酸性品红的去除率达到了95.41％.     

Electronic and mechanical responses of two-dimensional HfS2, HfSe2, ZrS2, and ZrSe2 from first-principles

During the last decade, numerous high-quality two-dimensional (2D) materials with semiconducting electronic character have been synthesized. Recent experimental study (Sci. Adv. 2017;3: e1700481) nevertheless confirmed that 2D ZrSe₂ and HfSe₂ are among the best candidates to replace the silicon in nanoelectronics owing to their moderate band-gap. We accordingly conducted first-principles calculations to explore the mechanical and electronic responses of not only ZrSe₂ and HfSe₂, but also ZrS₂ and HfS₂ in their single-layer and free-standing form. We particularly studied the possibility of engineering of the electronic properties of these attractive 2D materials using the biaxial or uniaxial tensile loadings. The comprehensive insight provided concerning the intrinsic properties of HfS₂, HfSe₂, ZrS₂, and ZrSe₂ can be useful for their future applications in nanodevices.     

含Al2O3的碲铌铅玻璃的性能研究

研究了含Al2O3的碲铌铅玻璃的性能并将之与不含Al2O3的玻璃的性能作了比较,结果表明,在碲铌铅玻璃中掺入Al2O3后,玻璃的密度和红外透过性能有所降低,玻璃转变温度升高,但此举并不改变其它组分对其性能变化趋势的影响。     

Degradation of 40 selected pharmaceuticals by UV/H2O2

The occurrence of pharmaceuticals in source waters is increasing. Although UV advanced oxidation is known to be an effective barrier against micropollutants, degradation rates are only available for limited amounts of pharmaceuticals. Therefore, the degradation of a large group of pharmaceuticals has been studied in this research for the UV/H₂O₂ process under different conditions, including pharmaceuticals of which the degradation by UV/H₂O₂ was never reported before (e.g., metformin, paroxetine, pindolol, sotalol, venlafaxine, etc.). Monochromatic low pressure (LP) and polychromatic medium pressure (MP) lamps were used for three different water matrices. In order to have well defined hydraulic conditions, all experiments were conducted in a collimated beam apparatus. Degradation rates for the pharmaceuticals were determined. For those compounds used in this research that are also reported in literature, measured degradation results are in good agreement with literature data. Pharmaceutical degradation for only photolysis with LP lamps is small, which is increased by using a MP lamp. Most of the pharmaceuticals are well removed when applying both UV (either LP or MP) and H₂O₂. However, differences in degradation rates between pharmaceuticals can be large. For example, ketoprofen, prednisolone, pindolol are very well removed by UV/H₂O₂, whereas metformin, cyclophosphamide, ifosfamide are very little removed by UV/H₂O₂.     

On the pressure dependence of flammability limits of CH2=CFCF3, CH2F2 and methane

Flammability limits of CH₂=CFCF₃ (HFO-1234 yf), CH₂F₂ (HFC-32), and methane were measured at pressures from ambient to 2500 kPa in a 5 l stainless-steel spherical vessel. For HFO-1234 yf, as the pressure rises from ambient, the lower flammability limit is shifted downward and the upper limit is shifted upward. The changes to the lower flammability limits are, in general, small compared to the upper flammability limits. Both the lower and upper flammability limits of this compound can be approximated by simple logarithmic functions of pressure. For HFC-32, the behavior of lower flammability limit is similar to that for HFO-1234 yf, but the behavior for the upper limit is rather complicated. As the pressure is increased, it begins to rise upward gradually. Then, as the pressure becomes larger than about 1000 kPa it begins to rise upward rapidly, and then the change becomes moderate again. This must be due to a change of combustion reaction mechanism below 1000 kPa and above 1500 kPa in the upper flammability limit region for this compound. On the other hand, both the flammability limits of methane change almost linearly with pressure, at least in the pressure region considered.     

Glyphosate degradation in water employing the H2O2/UVC process

Glyphosate is the organophosphate herbicide most widely used in the world. Any form of spill or discharge, even if unintentional, can be transferred to the water due to its high solubility. The combination of hydrogen peroxide and UV radiation could be a suitable option to decrease glyphosate concentration to acceptable limits. In this work, the effects of initial pH, hydrogen peroxide initial concentration, and incident radiation in glyphosate degradation were studied. The experimental device was a cylinder irradiated with two tubular, germicidal lamps. Conversion of glyphosate increases significantly from pH = 3-7. From this value on, the increase becomes much less noticeable. The reaction rate depends on the initial herbicide concentration and has an optimum plateau of a hydrogen peroxide to glyphosate molar concentration ratio between 7 and 19. The expected non linear dependence on the irradiation rate was observed. The identification of critical reaction intermediaries, and the quantification of the main end products were possible and it led to propose a plausible degradation path. The achieved quantification of the mineralization extent is a positive indicator for the possible application of a rather simple technology for an in situ solution for some of the problems derived from the intensive use of glyphosate.     

CO2 Park

On lucky occasions, one gets the Big Idea—the concept that will guide and critique the entire design process. It is usually to that concept that the designer returns to test out decisions. But for us the designing of CO₂ Park worked a bit differently: We started with an inkling of an idea—a fascination with the natural phenomenon, Aurora Borealis—and worked our way through the project as if we were following a thin and barely discernible thread. One idea engendered the next. Often we had barely finished what we had set our minds to before we were moving off in another direction. When we seemed to be at a dead end, we did not look to the concept for answers; instead, we turned back to the last successful model, sketch, or thought to find our direction.