Thermal and radiative characteristics of oxyfluoride glass singly doped with lanthanide ions

Rare earths-doped oxyfluoride glasses based on germanium oxide and lead fluoride were prepared from commercial raw materials. The glasses with general composition of 50GeO2-(50-x-y)PbO-yPbF2-xLnF3 (Ln=Pr3+-Yb3+), contained different concentrations of optically active dopants (x=0.2 mol.% and 2 mol.%) and PbF2 (y≤15 mol.%). The differential thermal analysis (DTA) was used to determine both thermal characteristic and thermal stability properties of the glasses in the function of the kind of dopant, its concentration, and a glass composition. Characteristic glass temperatures such as glass transition temperature (Tg), glass crystallization temperature (Tc) and temperature corresponding to the maximum of the crystallization rate (Tpc) were evaluated. On the basis of obtained results, the thermal stabilities of glasses under study were evaluated using various thermal stability criteria (Dietzel factor ?T, Saad-Poulain factors H' and S). It was found that the increase in rare earth fluoride contents influenced thermal characteristics when the characteristic temperatures of the individual glass was shifted towards higher values. The effect of the PbF2 content and the kind of rare earth impurity on the glass stability was observed. Absorption spectra of lanthanide-doped glasses were measured at room temperature and used to determine the phenomenological intensity parameters Ωt and next, to estimate radiative properties of lanthanide ions in this matrix. Radiative transition probabilities of luminescent states of Ln3+, branching ratios and radiative lifetimes were determined. The variation of the Ωt along the lanthanide series was presented and discussed.     

Hydrogen and syngas production from two-step steam reforming of methane over CeO2-Fe2O3 oxygen carrier

Two-step steam reforming of methane(SRM)is a novel chemical looping process towards the production of pure hydrogen and syngas(synthesis gas),consisting ofa syngas production step and a water-splitting step.Renewable energy can be used to drive this process for hydrogen production,especially solar energy.CeO2-Fe2O3 complex oxide oxygen carrier was prepared by the impregnation method and characterized by means of X-ray diffractometer(XRD),Raman spectroscopy(Raman)and hydrogen programmed reduction(H2-TPR).CH4temperature programmed and isothermal reactions were adopted to test syngas production reactivity,and water splitting reaction was employed to investigate water-splitting activity.Moreover,two-step SRM performance was evaluated by a successive redox cycle.The results showed that CO-uncontaminated H2 and highly selective syngas(with H2/CO ratio close to 2)could be respectively obtained from two steps,and CeFeO3 formation was found in the first redox cycle and proved to be enhanced by the redox treatment.After 10 successive cycles,obvious CeFeO3 phase was detected,which may be responsible for favorable successive redox cycle performances.     

Effect of erbium on properties and microstructure of Al-Si eutectic alloy

Eutectic Al-12.6 wt.%Si alloys with various contents of the rare earth dement Er were prepared by the conventional casting technique.The effect of Er on the microstructure and properties of the eutectic Al-Si alloys was investigated using optical microscopy,scanning electron microscopy as well as the friction and wear tests.It was found that the addition of Er obviously improved the anti-wear properties,and reduced the friction coefficient of the alloys.The appropriate addition of Er would change the size and shape of the eutectic silicon,and thereby refine the microstructure of the Al-Si alloys.The refinement mechanism was also discussed.     

Rare earth upconversion nanophosphors: synthesis, functionalization and application as biolabels and energy transfer donors

This review focused on rare earth upconversion nanophosphors (UCNPs), a particular class of emitters whose photoluminescence mechanism is of fundamental difference from that of conventional dyes and semiconductor quantum dots. We in the first section gave a brief summary on a variety of synthetic methodologies developed during the past decades. Instead of presenting an exhaustive reference list, we selected only a few representative examples, illustrating the merits and limits of each involved synthetic route. Then we surveyed the recent progress in the functienalization techniques for these nanomaterials, depicting the modification in microstruetures and improvement in prop-erties with respect to the parent nanopartides. And finally, we emphasized their application in the research fields of biolabeling and energy transfer, narrating their superior performance benefiting from the unique excitation and emission properties.     

Effect of Vanadium Microalloying on the HAZ Microstructure and Properties of Low Carbon Steels

Four Steels,C-Mn-0.05V,C-Mn-0.11V,C-Mn-0.03Nb and C-Mn were subjected to heat treatment to simulate the microstructure of a coarse grained heat affected zone (CGHAZ) and an intercritically reheated coarse grained heat affected zone (ICCGHAZ).This involved reheating to 1350°C,rapid cooling (Δt 8/5 =24s) to room temperature and then reheating to either 750°C or 800°C.The toughness of the HAZs was assessed using both Charpy and CTOD tests.Microstructural features were characterised by optical,scanning` and transmission electron microscopy.Fractographic examinations of the Charpy and CTOD specimens were carried out to understand the micromechanism of fracture under different microstructural and test conditions.The CGHAZ toughness was similar for the steels except that Steel C-Mn-0.05V had a slightly lower ITT compared to the others.The toughness deteriorated in the ICCGHAZ for all the steels,again Steel C-Mn-0.05V had a superior toughness compared to the other three steels in both ICCGHAZ conditions.Raising the level of vanadium to 0.11% caused a decrease in ICCGHAZ toughness.Steel C-Mn-Nb exhibited a greater degradation of impact toughness after the intercritical cycles.The presence of M-A constituents was the dominant factor in determining the toughness of the ICCGHAZs.The size and area fraction of the M-A constituents were the smallest in Steel C-Mn-0.05V.Increasing vanadium level to 0.11% resulted in a greater area fraction of the M-A constituents,larger average and maximum sizes of M-A particles,and significantly more fields containing the M-A.The addition of 0.031% Nb produced the largest M-A particles and the greatest area fraction for the steels tested.     

Process optimization of electroless copper plating and its influence on electrochemical properties of AB5-type hydrogen storage alloy

The amount of Cu coating by chemical plating was investigated based on quadratic regression orthogonal experimental design being adapted to the variation law of temperature,pH value and Ni2+concentration,and the relevant regression equation was expressed as y=2.1609+0.5295×10-3T2-0.0342P2-0.0265N2+0.0023TP+0.0020TH+0.0199PN-0.0959T+0.3814P-0.2073N.The results showed that the deposition rate augmented with the increasing in temperature,pH value and Ni2+concentration.The experimental parameters of the optimal coating were temperature 75 ℃,pH value 8.5 and Ni2+concentration 1.2 g/L.The electrochemical tests indicated that the cycle stability increased from 60.66% to 75.58%,indicating that the treated alloy exhibited better corrosion resistance.     

莱钢2#1 OOO m3高炉提高原燃料利用率的生产实践

莱钢2#1 000 m3高炉针对目前原燃料条件,优化筛分工作和炉料结构,通过更换振筛和改良振筛工作方式,将入炉粉末降至3%;通过加强块矿筛分及上下部制度调整相结合,改善了高炉透气性,燃料比降至515 kg/t;通过合理利用小焦块,提高了焦炭利用率,使高炉稳定顺行状况良好.     

Effect of titanium addition on the magnetic property of Nd2Fe14B/α-Fe nanocomposite alloys

Rapidly solidified nanocrystalline α-Fe/Nd2Fe14B alloys with enhanced coercivity were obtained by melt spinning.The effects of Ti addition on the microstructore and magnetic properties of the nanocomposite α-Fe/Nd2Fe14B alloys were investigated by X-ray diffraction(XRD)and superconducting quantum interference device(SQUID)magnetometer.The analysis of XRD showed that Vα-Fe estimated to be about 35.3% in the Ti-free α-Fe/Nd2Fe14B nanocomposites decreased down to 26.5% as the addition of was 5 at.% Ti.Accordingly,adding Ti resulted in relevant improvements of magnetic properties,especially of the coercivity Hc from 595 kA/m up to 1006 kA/m.The dependence of Mirrev(H)/2Mr on the reverse field H indicated that nucleation was the dominating mechanism for the magnetization reversal in these nanocomposites.The analysis of the temperature dependence of the demagnetization curve in the α-Fe/Nd2Fe14B nanocomposite magnets indicated that a reduction of αex could play a leading role in an increase in the coercivity of Ti-doped sample.     

天铁热力风机升级改造方案设计

通过对天铁集团高炉现状、风机现状的分析,提出了对热力厂风机升级改造的规划,确定了实施方案.该方案实施后将彻底改变风机渐进式改造的现象,使新高炉的备用机组发挥更大的作用,可增加现有高炉的风压、风量,使现有高炉的产量、冶炼强度进一步提高.     

离子交换-电解法生产镓过程中消泡剂的选用

在镓提取过程中,以离子交换法获得的电解原液碱度高,黏度大,电解时不断产生大量的氢气和氧气,形成大量泡沫,使电解无法正常进行.本研究通过试验选定2种消泡剂消除泡沫的不良影响.结果表明,这2种消泡剂不但不影响电解,反而对电解有利.     

转炉双渣操作炉渣中磷微区分布规律

对转炉双渣操作时的前期渣和终点渣中微观区域里磷的微观富集规律进行了研究,发现微区碱度Rm为2.0～2.5的微区中磷的富集程度最高;前期渣和终点渣中钙质量分数分别为16%～20%、33%～37%的微区中磷质量分数较高;微区磷富集与硅质量分数关系密切,终点渣微区中硅质量分数为9%～12%、前期渣微区中硅质量分数为13%～14%时,磷质量分数最高;微区铁质量分数对磷富集的影响明确,铁质量分数为5%～9%时磷质量分数最大;镁质量分数低的微区中磷质量分数较高。     

球团链箅机回转窑工艺中氯和硫元素迁移规律

摘要：对链箅机回转窑工艺中各段球团样品进行实验分析,研究了氯元素和硫元素在链箅机回转窑工艺中的迁移规律,明晰了烟气中HCl的生成机制。结果表明,球团原料中的氯元素主要是以NaCl的形式存在,氯元素有一部分在链箅机抽风干燥段会转变成HCl气体并进入烟气,一部分在链箅机预热Ⅱ段之后以NaCl的形式汽化进入烟气,剩余的氯元素仍以NaCl的形式存在于成品球团矿中。烟气中的HCl气体是在抽风干燥段,由富含SO2的烟气与含水球团料层中的NaCl发生反应生成的,烟气中SO2转变成Na2SO4重新固定于料层中。在预热Ⅰ段和预热Ⅱ段,烟气中的SO2与原料中碳酸钙分解生成的游离CaO反应生成CaSO4,也会重新固定烟气中的SO2。     

Introduction to the special section on cognitive processes and psychotherapy.

Theoretical models featuring cognitive processes have played a fundamental role in advancing knowledge of psychopathology and its treatment and have emphasized the importance of cognition in psychotherapy. Recognition of the importance of cognition in psychotherapy has led to a number of questions that are addressed by the articles in this special section of the Journal of Consulting and Clinical Psychology. Cognitive therapy is well represented in the articles in this special section, but therapeutic procedures that do not represent typical cognitive therapy are also examined. The articles in this special section focus on homework in the modification of cognition, cognition in the treatment of anxiety in adults and in children, change in depressive cognitions in children, cognition and rapid change in the treatment of depression, and the role of cognition in the treatment and prevention of depression that is recurrent. Examination of these types of questions holds the possibility of advances in existing treatments and the possibility of innovations in new treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

冀西北水晶屯金矿成矿控矿构造研究

水晶屯金矿床位于张宣幔枝构造轴部,水泉沟-大南山碱性角闪二长岩杂岩体的西缘。金矿化分布于尚义-赤城韧脆性剪切带中段。含金矿物主要为自然金和银金矿,赋存于石英、黄铁矿、方铅矿裂隙和胶结物颗粒间,矿石构造为细脉状、浸染状和团块状,围岩蚀变为硅化、黄铁矿化、绢云母化等。通过对本矿区的元素相关系数、硫、铅、氢、氧同位素特征等的研究分析,认为水晶屯金矿成矿物质主要是来源于深部的核幔物质,受构造控制明显。     

Flow Distribution Parameters in Relation to Flow Resistance in an Upflow Anaerobic Sludge Blanket Reactor System

The use of flow resistance in the distribution of flows is well known in traditional hydraulics. To evenly distributed flows, flow resistance forms the basis of flow distribution in pipes connected in parallel. Flow distribution in different zones of upflow anaerobic sludge blanket (UASB) reactors is well documented in existing literature, and so far modeling of flow distribution parameters, i.e., the fraction of inflow entering into the bed, the fraction of flow bypassing over the bed and entering into the blanket, and the fraction of inflow to the bed entering into the blanket, has remained empirical in nature. The role of flow resistance in the distribution of flows in UASB reactor systems is still unexplained. In this study, some of the available data on flow distribution parameters are analyzed to assess if there is any correlation between these parameters and flow resistance. It is found that with an increase in flow resistance in the UASB reactor system, the magnitude of short-circuiting flows at the reactor bed increases. Also, the flow distribution at the blanket and settler levels of UASB reactor systems is related to parameters influencing flow resistance. Some of the functional forms derived in this study are expected to form the basis for representing flow distribution in the simulation studies of UASB reactor performance.     

Experience-dependent cell survival in the maternal rat brain.

Postpartum maternal experience produces long-lasting changes in maternal behavior in the mother rat, which can be altered by early-life isolation. Postpartum experience also affects the regulation of adult neurogenesis in the neural circuit underlying maternal behavior, in a region-specific manner. Female rats were reared either with their mothers (MR) or in isolation in an artificial rearing (AR) paradigm. In adulthood, rats were mated and separated from their pups at birth. The following day, dams were injected with a mitotic marker and either allowed to interact with pups (maternal experience) or left alone. Results show that MR rats that acquire a later maternal experience show increases in cell survival in parts of the excitatory limb of the maternal neural network (bed nucleus of the stria terminalis and nucleus accumbens), but no changes in the inhibitory limb (amygdala). In comparison to AR inexperienced rats, AR maternally experienced rats show no increases in cell survival in the excitatory limb, but a striking reduction in cell survival in the inhibitory limb. The results suggest that early preweaning maternal isolation alters the structural plasticity that occurs following a postpartum maternal experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contribution of endogenous opioids to gonadal hormones-induced temporomandibular joint antinociception.

The authors have recently demonstrated that the high serum estradiol level during the proestrus phase of the estrous cycle and that the administration of estradiol or progesterone in ovariectomized female and of testosterone in orchiectomized male rats significantly decrease formalin-induced temporomandibular joint (TMJ) nociception. In this study, the authors investigate the contribution of endogenous opioids to this antinociceptive effect of gonadal hormones in the TMJ formalin test. The opioid receptor antagonist naloxone was administrated either in the surrounding of the trigeminal sensory complex or in the TMJ region. The antinociceptive effect induced by endogenous estradiol in proestrus females and by exogenous estradiol in ovariectomized females was blocked by the administration of naloxone in the surrounding of the trigeminal sensory complex, but not in the TMJ region. The antinociceptive effect induced by the administration of progesterone in ovariectomized females and of testosterone in orchiectomized males was blocked by the administration of naloxone either in the surrounding of the trigeminal sensory complex or in the TMJ region. The authors conclude that central and peripheral opioid mechanisms mediate the antinociceptive effect of progesterone and testosterone, and central opioid mechanisms mediate the antinociceptive effect of estradiol. These findings suggest that the enhanced pain perception during low gonadal hormone periods in women and animals may be mediated by a decrease in endogenous opioid activity. This suggestion helps explain the higher severity of some pain conditions, such as temporomandibular dysfunctions in women than in men, that have no hormonal fluctuations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement invariance versus selection invariance: Is fair selection possible?

This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in the location but not in the variance of the latent distribution, sensitivity and positive predictive value will be higher in the group at the higher end of the latent dimension, whereas specificity and negative predictive value will be higher in the group at the lower end of the latent dimension. When latent variances are unequal, the differences in these quantities depend on the size of group differences in variances relative to the size of group differences in means. The effect originates as a special case of Simpson's paradox, which arises because the observed score distribution is collapsed into an accept-reject dichotomy. Simulations show the effect can be substantial in realistic situations. It is suggested that the effect may be partly responsible for overprediction in minority groups as typically found in empirical studies on differential academic performance. A methodological solution to the problem is suggested, and social policy implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functions of Xyloglucan in Plant Cells

While an increase in the number of xyloglucan tethers between the cellulose microfibrils in plant cell walls increases the walls' rigidity, the degradation of these tethers causes the walls to loosen. Degradation can occur either through the integration of xyloglucan oligosaccharides due to the action of xyloglucan endotransglucosylase or through direct hydrolysis due to the action of xyloglucanase. This is why the addition of xyloglucan and its fragment oligosac-charides causes plant tissue tension to increase and decrease so dramatically. Experiments involving the overexpression of xyloglucanase and cellulase have revealed the roles of xyloglucans in the walls. The degradation of wall xyloglucan in poplar by the transgenic expression of xyloglucanase, for example, not only accelerated stem elongation in the primary wall, but also blocked upright-stem gravitropism in the secondary wall. Overexpression of cellulase also reduced xyloglucan content in the walls as cellulose microfibrils were trimmed at their amorphous region, resulting in increased cell volume in Arabidopsis leaves and in sengon with disturbed leaf movements. The hemicellulose xyloglucan, in its function as a tether, plays a key role in the loosening and tightening of cellulose microfibrils: it enables the cell to change its shape in growth and differentiation zones and to retain its final shape after cell maturation.     

锌在钢铁厂内的循环及危害

通过分析锌随钢铁制造流程的循环路径以及在高炉系统内的化学反应,明确了锌在钢铁厂内和高炉内部的循环,针对锌在钢铁厂内的循环路径,提出了减少和避免锌在高炉中循环富集的途径。根据高炉内的锌负荷和危害情况,提出了预防和控制高炉中锌量的措施。