具有核壳结构的纳米二氧化钛负载银离子掺杂稀土离子抗菌剂的合成、表征及抑菌活性研究

以纳米TiO2粉体和硝酸银及稀土硝酸盐(RE=Ce4+、La3+、Nd3+、Sm3+、Er3+)为原料,采用浸渍法制备了5种具有核壳结构的纳米二氧化钛负载银离子掺杂稀土离子抗菌剂.通过固体紫外-可见光谱、X-射线粉末衍射光谱、X-Ray光电子衍射光谱、透射电镜分析证明掺杂Ce4+的抗菌剂具有核壳结构.采用培养基扩散法、营养肉汤稀释法及贴膜试验对这五种抗菌剂进行了抑菌活性研究,最终证明其具有很好的抑菌性.     

cN0舌癌患者哨位淋巴结定位检测对于预测颈部淋巴结转移的研究

目的:探讨术前核素扫描+术中亚甲蓝示踪法+术中γ探头示踪法三联结合方法在从cNO期舌鳞癌前哨淋巴结定位的应用价值.方法:使用术前核素扫描+术中亚甲蓝示踪法+术中γ探头示踪法三联结合方法进行SN检测,以颈清扫标本的常规病理结果为金标准,评价其方法的功效.石蜡切片病理检查阴性的SN进一步行多层切片+免疫组化检查.结果:20例中SN检出率为100%( 20/20),隐匿性淋巴结转移的发生率为25%(5/20),SN活检评价颈淋巴结转移状况的准确率为95%(19/20),假阴性1例,阴性预测值均为94%(15/16).结论:术前核素扫描+术中亚甲蓝示踪法+术中γ探头示踪法三联结合方法cNO期舌鳞癌哨位淋巴结转移有较高的临床应用价值.     

不同同期发情处理方法对受体牛同期发情效果的影响

[目的]探索一种高效、低耗的牛同期发情方法,为后期的胚胎移植奠定基础.[方法]选择120头健康经产黄牛作为胚胎移植受体,随机分为3个组.Ⅰ、Ⅱ和Ⅲ组黄牛分别采用1次注射4.0 mg前列腺素法、阴道栓+4.0mg前列腺素法和阴道栓+0.4 mg前列腺素+2 ml促卵泡素法进行同期发情处理.比较不同方法的同期发情率、输胚率和淘汰受体牛率.[结果]Ⅰ、Ⅱ、Ⅲ组黄牛的同期发情率分别为80.0%和77.5%;Ⅰ、Ⅱ、Ⅲ组黄牛的输胚率分别为27.5%、60.0%和45.0%.[结论]采用阴道栓+4.0 mg前列腺素法为最佳的黄牛同期发情方法.     

复合熔盐法合成Y2O3.Eu3+红色荧光粉

以草酸钇铕(Y2(C2O4)3:Eu3+)为前驱体,采用复合熔盐(NaCl+S+Na2CO3)协助焙烧法合成Y2O3:E.u3+红色荧光粉.利用XRD、SEM、光谱分析等测试和分析荧光粉粒径、颗粒形貌以及发光性能.主要考察复合熔盐配比、用量以及焙烧温度和时间对Y2O3:Eu3+荧光粉发光性能的影响.结果表明,NaCl在...     

并流沉淀法降低铜电解液中砷锑铋杂质离子的研究

铜电解液中的As、Sb、Bi离子含量是影响阴极铜质量的重要因素,现有的电解沉积法电耗高、铜损失量大,萃取方法和离子交换法存在液量大的缺陷.本文利用SO2还原As5+和Sb5+、H2O2氧化As3+和Sb3+调整化合价,促使砷锑铋形成沉淀阳极泥的原理,进行了二氧化硫和双氧水并流沉淀方法降低铜电解液中砷锑铋杂质离子的实验研...     

La掺杂对TiO2光催化剂的影响

采用溶胶-凝胶法制备了La掺杂的TiO2.通过X射线衍射分析、扫描电镜、紫外-可见光漫反射测试等手段对TiO2进行了结构和光吸收性能研究.结果表明La3+阻碍了锐钛矿向金红石转变,提高了晶形转变温度,La3+掺杂之后的TiO2粒径变小,La3+掺杂TiO2光吸收与煅烧温度有关.     

一类特殊的高次不定方程

本文运用Eisenstein判别法及其变化形式,证明了方程f(x)=apxp+ap-1xP-1+…+ap-kxP-k+…+a1x+a0=0(这里p是任一奇素数)无有理根,从而证明了高次不定方程xp+yp=zp无正整数解.     

La、Ce掺杂对水热法合成镍锌铁氧体的影响

采用水热合成法制备镍锌铁氧体粉体,以稀土元素La、Ce进行掺杂,利用SEM和XRD 等手段对样品进行表征.结果表明,La3+、Ce3+掺杂后,La3+、Ce3+离子掺杂进入镍锌铁氧体晶格后,会产生一定的晶格畸变,造成晶粒常数的增大,但对晶体的形貌影响不大.除存在少量大颗粒,立方尖晶石相Ni0.35Zn0.65Fe1.9...     

溶胶-凝胶法合成Y2O3-SiO2:Eu3+,Bi3+发光体及发光特性研究

采用溶胶-凝胶法低温合成了Y2O3-SiO2:E u3+,Bi3+发光体,研究了烧结温度、Eu3+及Bi3+浓度、Y 2O3与SiO2的配比对发光强度的影响.通过X射线粉末衍射、热重及差热分析,研究了由凝胶至发光晶体的转变,通过激发光谱和发光光谱的测试,讨论了材料的发光特性及Bi 3+对Eu3+的敏化作用.     

BaAl12O19中Mn2+和Tb3+的发光及Tb3+对Mn2+的能量传递

采用溶胶-凝胶法合成了Mn2+、Tb3+单掺及共掺的BaAl12O19荧光粉,对其发光性质和Tb3+对Mn2+的能量传递机理进行了研究.研究结果表明,Tb3+单掺的BaAl12O19荧光粉,发射峰位于440nm、489nm、543nm、587nm和623nm,属于Tb3+的5D3→7FJ和5D4→7FJ (J=6,5,4,3)跃迁发射;Mn2+单掺的荧光粉,发射峰位于516nm,归属于Mn2+的4T1→6A1跃迁发射.Mn2+,Tb3+共掺后,Mn2+的发射强度明显提高,而Tb3+的发光强度降低,Tb3+对Mn2+有能量传递作用.初步证实Tb3+对Mn2+的能量传递机理为激子能量传递.     

Effects of Top Layer, Nozzle Arrangement, and Gas Flow Rate on Mixing Time in Agitated Ladles by Bottom Gas Injection

This research investigates mixing phenomena in bottom gas-stirred ladles using water modeling, which incorporates hexane as the top layer. The effects of slag thickness, nozzle position, number of nozzles, and gas flow rate on mixing time have been investigated. Conditions to improve mixing time have been identified. A single nozzle located at two-thirds of the ladle radius was found to produce the shortest mixing time. Under extremely low gas flow rates, an unusual behavior was observed, where the top layer promoted a decrease in mixing time.     

Development of blast furnace quality pellet optimising blue dust,hard ore and friable ore ratio

Three types of ore fines such as hard ore (HO), blue dust (BD) and friable ore (FO), normally available from a mine show different physical and physicochemical properties. Each of the properties of any individual ore among three may not be suitable to use independently in pelletisation. However, uses of all these three are mandatory. Ores of some poor properties may show other properties excellent. Therefore, any specific poor property of any individual ore can be modified by adding (mixing) other ore which shows that particular property excellent. In order to utilise those three ore fines in pelletisation, mixing of above three ores have been done to get good pellet properties. In industry, the fluctuation in mixing ratio often creates problem in maintaining pellet quality and consistency in spite of maintaining identical basicity and MgO content. Therefore, the required mixing ratio and pellet chemistry has also been optimised in this study. BD, FO and HO has been found to be suitable in the mixing ratio of 70:25:5 with 1.4% MgO. However, with increase in FO beyond 50%, reduction degradation index (RDI) becomes very high (25%). RDI has been decreased to very low level by increasing MgO content from 1.4 to 2% which enables to use FO up to 70% for good quality pellet preparation.     

Turbulent Velocity in Flocculation by Means of Grids

Eleven types of single circular biplane grids with different diameter (d) and mesh (M) were vertically and constantly oscillated inside a 2 L square jar. The velocity components were measured using a 2D laser doppler anemometer. The average root-mean-square turbulent velocity q′ values were found to be relatively constant at both vertical and horizontal points of measurement—a condition that could not be achieved in the case of impeller mixing. Since the mixing intensity was uniform within the jar, the average volume velocity gradient ? could be applied as the surrogate mixing intensity parameter. It was also found that q′ was linearly related to the vertical grid speed and grid physical characteristics, indicating that the mixing was easily controlled. The macro length scale (L) was calculated and was found to be constant and proportional to d or M, as it should be in the case of turbulent mixing. This study shows the potential of grids as the mixing devices that can be expected to produce an optimum mixing environment for the flocculation process.     

Effects of surface flow control on fluid flow phenomena and mixing time in a bottom blown bath

The intensity of mixing in a molten metal bath stirred by bottom gas injection can be represented by the mixing time. According to previous water model experiments, the mixing time is known to be dependent on the operational variables such as the bath diameter, bath depth, location of a bottom nozzle, and gas flow rate. It is not easy to control the former three variables during processing, and the dependence of the mixing time on the gas flow rate is weak. In this study, the possibility of changing the mixing time drastically due to the control of the surface flow in the bath is examined. Three kinds of boundary conditions were imposed on the bath surface, and the relation between the fluid flow phenomena resulting from the surface flow control and the mixing time was investigated. The mixing time was found to be significantly influenced by the surface flow control. In particular, when the surface flow was suppressed by bringing a circular cylinder into contact with the bath surface, the mixing time became very long.     

Distributed Entrainment Sink Approach for Modeling Mixing and Transport in the Intermediate Field

In densely populated coastal cities in Asia, wastewater outfalls are often located not far from sensitive areas such as beaches or shellfisheries. The impact and risk assessment of effluent discharges poses particular technical challenges, as pollutant concentration needs to be accurately predicted both in the near field and intermediate field. The active mixing close to the discharge can be modeled by proven plume models, while the fate and transport far beyond the mixing zone can be well-predicted by three-dimensional (3D) circulation models based on the hydrostatic pressure approximation. These models are usually applied separately with essentially one-way coupling; the action of the plume mixing on the external flow is neglected. Important phenomena such as surface buoyant spread or source-induced changes in ambient stratification cannot be satisfactorily addressed by such an approach. A Distributed Entrainment Sink Approach is proposed to model effluent mixing and transport in the intermediate field by dynamic coupling of a 3D far field shallow water circulation model with a Lagrangian near-field plume model. The action of the plume on the surrounding flow is modeled by a distribution of sinks along the plume trajectory and an equivalent diluted source flow at the predicted terminal height of rise. In this way, a two-way dynamic link can be established at grid cell level between the near and far-field models. The method is demonstrated for a number of complex flows including the interaction of a confined rising plume with ambient stratification, and the mixing of a line plume in cross flow. Numerical predictions are in excellent agreement with basic laboratory data. The general method can be readily incorporated in existing circulation models to yield accurate predictions of mixing and transport in the intermediate/far field.     

Thermodynamics of oxygen solutions in liquid Ni,Co, Fe,and Mn metals

Pure gaseous oxygen at a pressure $p_{O_2 }^{1/2} = 1$ is taken as the standard state of oxygen dissolved in a liquid metal. In the case of such a standard state of oxygen, its activity is equal to the equilibrium oxygen partial pressure in the vapor, which is risen to a power of 1/2. This allowed us, using two thermodynamic functions, i.e., the standard Gibbs energy for the oxidation reaction of liquid metal with oxygen to form a lower oxide and the experimentally determined oxygen solubility in a liquid metal, to obtain equations for the energies of mixing of each metal with oxygen and to calculate them, to find linear temperature dependences of the energies of mixing, and to describe oxygen solutions in liquid metals by pseudoregular-solution model equations. Linear dependences of the solubility functions on the standard Gibbs energies for oxidation reactions of liquid metals are found. The aim of the study is to suggest the energies of mixing of four metals (Ni, Co, Fe, and Mn) with oxygen and their temperature dependences for the calculations of the activity coefficients and the activity of oxygen in the solutions of these liquid metals by the pseudoregular-solution model equations.     

Studies on membrane fusion. I. Interactions of pure phospholipid membranes and the effect of myristic acid, lysolecithin, proteins and dimethylsulfoxide

The interaction and mixing of membrane components in sonicated unilamellar vesicles and also non-sonicated multilamellar vesicles prepared from highly purified phospholipids suspended in NaCl solutions has been examined. Electron microscopy and differential scanning calorimetry were used to characterize the extent and kinetics of mixing of membrane components between different vesicle populations. No appreciable fusion was detected between populations of non-sonicated phospholipid vesicles incubated in aqueous salt (NaCl) solutions. Mixing of vesicle membrane components via diffusion of phospholipid molecules between vesicles was observed in populations of negatively charged phosphatidylglycerol vesicles but similar exchange diffusion was not detected in populations of neutral phosphatidylcholine vesicles. Incubation of sonicated vesicle populations at temperatures close to or above the phospholipid transition temperature resulted in an increase in vesicle size and mixing of vesicle membrane components as determined by a gradual change in the thermotropic properties of the mixed vesicle population. The interaction of purified phospholipid vesicles was also examined in the presence of myristic acid and lysolecithin. Our results indicate that while these agents enhance mixing of vesicle membrane components, in most cases mixing probably proceeds via diffusion of phospholipid molecules rather than by fusion of entire vesicles. Increased mixing of vesicle membrane components was also produced when vesicles were prepared containing a purified hydrophobic protein (myelin proteolipid apoprotein) or were incubated in the presence of dimethylsulfoxide. In these two systems, however, the evidence suggests that mixing of membrane components results from the fusion of entire vesicles.     

Activities and free energies of mixing in binary silicate melts

The thermodynamic properties of the Whiteway, Smith and Masson (WSM) models of polymerized silicate melts are calculated. The free energy is calculated as a function of composition and degree of polymerization of the silicate ions from heats of mixing and Guggenheim’s expression for the configurational entropy of a system of linear and branched chain polymer molecules in which random mixing of the mer units occurs. The variations, with composition, of the equilibrium degree of polymerization, the activities of solution components and the free energy of mixing are calculated as functions of the stability of the solid orthosilicate compound. Under the assumption of random mixing of the mer units, the thermodynamic properties are found to be independent of whether the SiO _in4 ^su4 ion is considered to be a bifunctional or tetrafunctional polymerizing unit. It is found that the apparent differences between the dependencies, on composition, of the ion fraction of O^2- in the WSM linear chain model and the WSM branching chain model are the result of the assumption, in these models, that random mixing of the anions occurs,i.e. that the systems exhibit Temkin behavior. It is suggested that the deviations of the theoretical free energies of mixing from experimental measurement, which begin when the mole fraction of silica is between 0.3 and 0.4, are due to the first significant appearance of ring ions in actual silicate melts at some composition within this range.     

形状和密度差异大的两组元颗粒混合工艺研究

选取不锈钢微球和铝粉为形状和密度差异大的两组元颗粒,采用盘式混料机进行混合,系统研究了颗粒润湿剂用量、混合时间、混合转速和料罐填充率对物料混合度的影响。采用变异系数法分析了混合物料的混合度。结果表明,最佳混合工艺参数为:颗粒润湿剂用量1.5%(质量分数)、混合时间90 min、混合转速40 r/min和料罐填充率30%,其物料混合度为93.4%;4种混合因素对混合度的影响程度为:混合时间料罐填充率混合转速颗粒润湿剂用量。