X-射线荧光光谱法测定硅石中主次成分

采用硅石标准样品及其复配标准样品作为校准样品,建立了熔融制样X-射线荧光光谱法测定硅石中SiO2,Fe2O3,Al2O3,CaO,MgO,K2O,TiO2,MnO,P2O5主次成分的方法。采用熔融法为试料片和校准片的制备方法,通过试验选择四硼酸锂-偏硼酸锂混合熔剂(12∶22,m/m)为助熔剂、1.00 mL LiBr溶液为脱模剂、稀释比为1∶20、熔融时间30 min。采用可变理论α系数对基体效应进行校正。对同一硅石样品进行测定的相对标准偏差(RSD)小于8%,对不同硅石样品进行测定,本法的测定结果与标     

X射线荧光光谱法测定铜矿中主次成分

以四硼酸锂-偏硼酸锂混合熔剂(m/m=12∶22)作熔剂,采用熔融法制样,建立了测定铜矿石中Cu、S、Pb、Zn、As、Fe、Mn、SiO2、Al2O3、MgO、K2O、CaO、TiO2的X射线荧光光谱(XRF)法。讨论了预氧化温度和脱模剂的添加顺序对样品制备的影响,解决了硫化铜矿石样品对铂黄坩埚的腐蚀问题,并选择合适的校正程序进行谱线重叠和基体效应的校正。采用国家标准样品和人工合成标准样品来绘制校准曲线,线性范围较宽。对铜矿样品测定11次,相对标准偏差(RSD)为0.27%~19%;对用标准样品合成的样品进行分析,测定值与认定值相一致。分析结果的精密度和正确度能够满足一般铜矿的分析要求。     

X-射线荧光光谱法测定磷矿中五氧化二磷、氧化钙、三氧化二铁、氧化铝、氧化镁和二氧化硅

采用四硼酸锂和偏硼酸锂混合熔剂[m(Li2B4O7)∶m(LiBO2)=12∶22]熔融磷矿样品制成玻璃样片,用波长色散X-射线荧光光谱仪测定样片中P2O5,CaO,Fe2O3,Al2O3,MgO和SiO2含量。用磷矿标样经同法测定并对测定结果进行理论α系数校正后绘制工作曲线。用本法对一试样测定11次,得到各组分的相对标准偏差小于1.2%。本法已用于磷矿样品分析,测定结果与化学法一致。     

X射线荧光光谱法测定氧化锆质耐火材料中主次成分

以无水四硼酸锂和碳酸锂混合熔剂作熔剂,采用玻璃熔片法制样,建立了测定氧化锆质耐火材料中ZrO2、HfO2、Al2O3、SiO2、Fe2O3、TiO2、CaO、MgO、Y2O3等组分的X射线荧光光谱法(XRF)。根据氧化锆质耐火材料中主次成分含量范围,采用有证参考物质和具有成分含量梯度并经其他方法定值的自制标准样品绘制校准曲线。并对熔剂选择、熔融条件及基体效应校正进行了探讨。将X射线荧光光谱法用于3个稳定氧化锆试样的分析,并与ICP-AES法进行比对,测试结果吻合。     

熔融玻璃片法X射线荧光光谱测定铁矿石中的主次量组分

采用四硼酸锂和偏硼酸锂混合熔剂(质量比为67∶33)为助熔剂制备玻璃片,建立了X射线荧光光谱法测定铁矿石中Fe2O3、SiO2、Al2O3、CaO、MgO、P、Ti、K2O、Mn等组分含量的方法。以12个铁矿石的标准物质建立校准曲线,研究了溶剂、稀释比例、脱模剂以及温度和时间的影响,用理论α系数法进行回归校正。方法准确、快速、简便。     

X射线荧光光谱法测定氧化铝中杂质含量

对X射线荧光光谱测定氧化铝中杂质元素的方法进行了研究。利用系列标准样品制作工作曲线,采用混合熔剂四硼酸锂加偏硼酸锂(12+22)熔融制样法分析了SiO2,Fe2O3,Na2O,制备熔片的稀释比为1∶3;直接压片制样法分析了TiO2,V2O5,P2O5,ZnO。SiO2,Fe2O3,Na2O,TiO2,V2O5,P2O5,ZnO测定结果的RSD分别为2.61%,2.61%,2.33%,4.62%,8.24%,8.00%和1.79%。该方法用于氧化铝生产控制及产品分析,数据准确、可靠,结果令人满意。     

熔融制样-X射线荧光光谱法测定三氧化钼中7种组分

采用无水四硼酸锂熔融制样,建立了用波长色散X射线荧光光谱（XRF）法测定三氧化钼中MoO3、Pb、Cu、SiO2、CaO、Fe2O3、K2O 7种组分的方法。以Mo为主要分析元素分别对仪器参数、分析谱线、曲线拟合进行了研究,并详细讨论了熔融法制样条件中熔剂的选择、脱模剂的选择、熔融温度和熔融时间的确定。采用经过多次化学分析的样品作为标准样品绘制校准曲线并选择相应校正程序进行校正。该法用于三氧化钼样品的分析,结果同湿法分析数据相吻合,能满足生产中三氧化钼样品中七种组分分析的需要。     

X射线荧光光谱法快速分析消泡剂

以四硼酸锂为熔剂熔融制样,建立了消泡剂中SiO2、Al2O3、CaO、MgO、Fe2O3和Na2O的X射线荧光光谱分析方法,考察了不同稀释比例的玻璃熔片制备的重复性,讨论了烧失量的影响。本方法采用国家标准样品和人工合成样品来制作工作曲线,通过精密度和准确度实验,表明本方法准确可靠,能满足生产要求。     

X射线荧光光谱法测定镁砂、镁石及菱镁矿中主次成分

以标准物质作为参照物,采用熔融法制样,建立了测定镁砂及其矿物原料(镁石、菱镁矿)中SiO2、Al2O3、CaO、MgO、Fe2O3、MnO、P2O5、TiO2含量的X射线荧光光谱法。讨论了熔融制样采用的熔剂体系、样品与熔剂的稀释比例、融熔制样的温度和时间对制样精度及测量准确度的影响。探讨了镁石、菱镁矿等碳酸盐样品烧损量对测定结果的影响和校正方法。本方法应用于镁砂、镁石、菱镁矿标准样品及镁砂实际样品的分析,测定值与认定值或其他方法的测定值相一致,所得分析结果能够满足镁砂中常见组分快速分析的需要。     

x射线荧光光谱测定镁质耐火材料的主次成分

采用高频感应熔融法制样，建立了镁质耐火材料中MgO、Cr2O3、Al2O3、Fe2O3、CaO、SiO2、TiO2的x射线荧光光谱分析方法。考察了熔剂、熔剂试样比以及熔融温度和时间对熔片熔融效果的影响，验证了熔片的均匀性。本方法采用标准样品及人工合成样品共15个制作了各成分具有一定浓度梯度的标准曲线，用理论α系数法校正基体的吸收增强效应。本法分析结果与化学值的一致性较好，且具有较高的精密度。     

Polyneuropathy due to ethylene oxide, propylene oxide, and butylene oxide

Radioligand exchange was examined for its ability to derive the dissociation constant (Kd) of the rat ventral prostate nuclear androgen receptor. In one 24-h, 12 degrees C incubation, Scatchard plot analysis of [3H]dihydrotestosterone ([3H]DHT) exchange binding produced a Kd of 6.9 x 10(-9) M. Specific binding of [3H]DHT ranged from 114 to 758 pM, and the extrapolated value for the total number of binding sites (n) was 1320 pM. When aliquots from the same receptor pool were incubated with unlabeled DHT, and bound androgen was measured by radioimmunoassay, each titration point held a concentration of specifically bound unlabeled DHT little different from the preincubation value of bound endogenous ligand (1338 pM), suggesting that few, if any, unoccupied sites were created during the incubation. In a second radioligand exchange assay, unoccupied receptor sites were measured at the end of incubation. Virtually no unoccupied sites were found, though the range of predicted values was 124 to 383 pM (n = 425 pM). The data, in toto, suggest that although radioactive ligand exchanges with bound unlabeled ligand, the dynamics of the process do not include the creation of unoccupied sites. Since the Kd is determined by measuring the concentrations of unoccupied sites, free ligand, and receptor sites bound to ligand, the absence of unoccupied sites suggests that radioligand exchange cannot be used to directly determine the Kd of the prostate nuclear androgen receptor. The numerical value obtained from radioligand exchange, therefore, instead of being a Kd, is very likely the result of a graphic plot of the increase in specific activity of bound radioligand as [3H]DHT is titrated to higher levels. In the last phase of the study a technique was developed which allows for the correct determination of the Kd of the rat ventral prostate nuclear androgen receptor. For the determination, data from an experiment measuring uptake binding into unoccupied sites were combined with data obtained from radioligand exchange binding. From this, the Kd of the receptor was calculated to be 1 x 10(-12) M.     

Nitric oxide

Nitric oxide (NO) is a gas with diverse biological activities produced from arginine by NO synthases. It is capable of interacting with a number of molecules, most notably superoxide, forming peroxynitrite, which, in turn, can mediate bactericidal or cytotoxic reactions. Nitric oxide also mediates smooth muscle relaxation, neurotransmission, and modulation of inflammation in a number of organ systems and pathophysiologic conditions. Modulation of NO by administration of inhaled NO for respiratory distress syndromes and infusion of NO synthase inhibitors in bacterial sepsis are ongoing. Levels of exhaled NO are being evaluated for their utility in assessing inflammation in respiratory disorders such as asthma.     

氧化铝基氧化物/氧化物复合材料的合成与评价

Al2O3 matrix oxide/oxide composites containing rod-like Ba-β-Al2O3 and equiaxed ZrO2 particles have been successfully synthesized by an in-situ process from a mixture of Al2O3 and BaZrO3 powders.The long-axis direction of rod-like Ba-β-Al2O3 phase is parallel to ,while the longitudinal interface between Ba-β-Al2O3 phase and Al2O3 matrix is parallel to(0001) of the Ba-β-Al2O3 phase.The mechanical properties of the composites,such as Vickers hardness and fracture toughness,are enhanced with increasing the sintering temperature.Furthermore,the presence of rod-like Ba-β-Al2O3 particles results in enhancement of fracture toughness of the in-situ synthesized composites due to crack deflection and crack bridging.     

X-荧光光谱法分析铝土矿中的氧化铁、氧化硅、氧化铝

建立了X荧光法测定铝土矿中主要成分氧化铁、氧化硅、氧化铝的方法。将铝土矿样品以四硼酸锂做熔剂,氟化锂做助熔剂,碘化铵做脱模剂高温熔融制备成玻璃熔片,以标准物质和自制标样做校准曲线,按选定的仪器条件测量强度,按预先建好的校准曲线计算结果,并与化学法进行对照,结果基本一致,本方法操作简单、快速,准确度和精密度均达到国家标准方法规定的要求。     

从钕铁硼废料中回收稀土及氧化钴的条件试验

研究了从钕铁硼废料中回收稀土氧化物和氧化钴的工艺流程,试验确定了酸分解,草酸沉淀,除铁等杂质的工艺条件,该工艺能有效地除去铁,钙等杂质,试验得到的氧化钴符合GB6518－86纯氧化钴粉Y1类产品要求,钴直收率在82％以上,所得稀土氧化物,其总含量为97％以上,回收率95％以上,达到了综合回收利用的目的。     

Solid oxide membrane process for magnesium production directly from magnesium oxide

The solid oxide membrane (SOM) process is an emerging technology for the environmentally friendly extraction of high-energy-content metals such as magnesium, tantalum, and titanium directly from their respective oxides. This paper reports on the recent success of the SOM process for magnesium production from magnesium oxide dissolved in fluoride-based fluxes in the temperature range 1150 °C to 1300 °C. This process employs an inert oxygen-ion-conducting stabilized zirconia membrane to separate the inert cathode in the flux from the anode. When the applied electrical potential between the electrodes exceeds the dissociation potential of magnesium oxide, oxygen ions are pumped out of the melt and through the zirconia membrane to the anode where they are oxidized. Reduced magnesium evolves at the cathode as a vapor and is condensed in a separate chamber yielding a high-purity product. The SOM cell has been electrochemically characterized, and key concepts related to MgO dissociation, leakage current, and mass transfer relevant to the SOM process are explained.