Luminescence studies of MBrCl： Eu2＋ （M=Ca, Sr, Ba）

Europium doped MBrCl (M=Ca, Sr, and Ba) phosphors were prepared by solid state reaction in reductive atmosphere. Photolu-minescence (PL), photostimulated luminescence (PSL) after X-ray irradiation and optical absorption studies of MBrCl:Eu2+ (M=Ca, Sr, and Ba) revealed that: (1) blue light emission, under the excitation of 300 nm, was observed in all these phosphors; (2) the shape of the emission spectra in CaBrCl:Eu2+ could be changed by varying the bromine/chlorine ratio during synthesis, while that in SrBrCl:Eu2+ and BaBrCl:Eu2+ showed no change; and (3) PSL was observed in SrBrCl:Eu2+ and BaBrCI:Eu2+ after X-ray irradiation. Difference absorption spectrum (DAS) in SrBrCl:Eu2+ showed two broad bands centered at about 470 and 570 nm, and DAS in BaBrCI:Eu2+ showed two bands at about 550 and 675 nm, respectively. This enabled the use of He-Ne laser (633 nm) or even semiconductor light-emitting diodes (LED) instead of gas lasers for photostimulation.     

Enhancement of photoluminescence of Ba2SiO4：Eu^2＋ by co-doping of La^3＋ or Y^3＋

Green light-emitting Ba2SiO4:Eu2+ phosphors co-doped with La or Y were synthesized by conventional solid-state reaction technique in reductive atmosphere (a mixture of 5% H2 and 95% N2). The results showed that the co-doping of La and Y could greatly enhance the fluorescence intensity of Ba2SiO4:Eu2+ phosphors. The optimum doping concentration expressed by the x value in (Ba0.985-1.5xREx)2SiO4: 0.03Eu2+ (RE=La or Y) was determined to be of 0.05. The excitation and emission peaks of all as-synthesized phosphors were wide bands. The excitation bands ranged from 250 to 400 nm, which matched well with the wavelength of near ultraviolet white light-emitting diodes (LED) chip and could be used as a potential candidate for the fabrication of white LED. The emission bands from 450 to 550 nm were typical 5d-4f transition emission of Eu2+ and displayed un-symmetry profiles because of the two substitution sites of Ba2+ with Eu2+.     

细菌在净化废水方面的应用

本文分析了细菌的种类 ,影响细菌增殖的主要因素 ,以及利用细菌处理废水的基本原理。分别阐述了氧化铁硫杆菌 ,氧化硫细菌 ,硫酸盐还原性细菌在净化废水方面的应用。     

影响COD测定因素探讨——样品保存时间和样品回流冷却后放置时间的影响

化学需氧量（CODcr）是指在一定条件下,用强氧化剂处理水样时所消耗氧化剂的量,以氧的毫克／升来表示。化学需氧量反映了水中受还原性物质污染的程度,水中还原性物质包括有机物、亚硝酸盐、亚铁盐、硫化物等。     

富氢还原对烧结矿还原性及还原粉化的影响

钢铁工业CO2排放量约占全球总排放量的8%,为了降低CO2排放量,发展以H2为还原剂的炼铁生产方式势在必行。针对富氢还原对烧结矿还原性及还原粉化的影响进行了试验研究和理论分析。研究结果表明：H2等量代替CO时,H2体积分数由0%增加到12%,烧结矿的RDI-3.15降低约1%~2%;H2等量增加,CO,CO2,N2含量等比例降低时,H2体积分数由0%增加到12%,烧结矿的RDI-3.15升高约1.5%~2.5%;H2体积分数从0%增加到12%,烧结矿还原度Ri由72.56%增加到94.97%。研究结果对于开发富氢还原工艺具有重要的理论参考价值。     

硫酸根和硝酸根对ZVI-SRB处理铀废水的影响研究

利用硫酸盐还原菌(SRB)和还原性铁粉(Zero Valent Iron,ZVI)还原沉淀废液中的铀,研究了硫酸根和硝酸根对SRB体系和ZVI-SRB体系还原沉淀废液中的铀的影响.试验结果表明,这2个酸根离子对SRB体系和ZVI-SRB体系处理铀废水有一定的影响.硫酸根的质量浓度低于4000mg/L对硫酸盐还原菌还原沉淀铀没有影响,但当硫酸根的质量浓度超过6000mg/L时,铀的去除率会显著下降,从80%以上降到14.1%;有硫酸根时,铀的最终除去率ZVI-SRB联合处理比SRB单独处理要高.低浓度的硝酸根有助于SRB的还原代谢,高浓度的硝酸根抑制SRB的生长代谢,进而影响铀废水的处理效率,当硝酸根的质量浓度达到1500mg/L,铀的去除率不到0.1%,而硝酸根的质量浓度低于1000mg/L,铀的去除率可达75%以上;有硝酸根时,加铁粉的SRB的铀除去率比没加铁粉的去除率都要低.     

焙烧工艺对球团矿还原性能的影响

针对承钢球团矿的原料特点,研究了不同膨润土配比和焙烧工艺条件对承钢钒钛磁铁矿球团还原性能的影响。试验结果表明,承钢竖炉球团造球过程中,膨润土配比控制在2%~3%之间,焙烧温度控制在1 200~1 250℃,焙烧时间控制在30 min,对球团矿的中温还原性有利。     

合理使用灯光提高节目制作质量

本文从视频与灯光的关系入手 ,讨论提高电视节目制作质量的途径。1　彩色还原性彩色自然、肤色正常是对电视节目技术质量的基本要求。1.1　光源的色温与彩色还原性光源所发射的光的颜色与绝对黑体在某一温度下的热辐射光的颜色相同时 ,用绝对黑体的对应温度表示该光源的光谱成分 ,并称该温度为光源的色温。只有当光源的色温与摄像机的滤色片相对应时 ,拍摄对象的色彩才能正确重现。通常演播室使用卤钨灯作为照明的灯具 ,在额定电压 2 2 0Ｖ时 ,它的色温为 32 0 0Ｋ ,每降低 1Ｖ电压 ,色温就降低 5Ｋ。如果色温偏差超过摄像机允许的范围 ,就…     

添加硼铁精矿对球团矿抗压强度和还原性能的影响

本文对不同焙烧温度下，焙烧不同硼铁精矿配入量的球团矿抗压强度和还原性变化作了深入研究。球团矿配国适量的硼铁精矿有利于提高抗压强度、改善还原性，特别是在较低的焙烧温度条件下，硼铁精矿的作用更为明显。