小儿血液金属元素浓度与血细胞参数关系

目的探讨小儿血铅、镉、铜、锌、钙、镁、铁浓度与血细胞参数的相互关系。方法采用原子吸收分光光度仪、血球计数仪分别对门诊健康体检小儿297人进行金属元素浓度测定与血细胞计数,并以SPSS11．5统计软件对金属元素浓度与红细胞（RBC）、WBC（白细胞）、血小板（PLT）等常项进行多元逐步回归分析。结果多元线性逐步回归分析显示外周WBC、PLT受血镁、血铁浓度影响大;RBC受血锌,血红蛋白（Hb）和红细胞压积（Hct）受血钙与血铁,红细胞平均体积（MCV）、红细胞分布宽度（RDW）受血锌、血钙和血铁,红细胞平均血红蛋白量（MCH）、红细胞平均血红蛋白浓度（MCHC）受血锌和血铁,淋巴细胞比率（L％）、中间细胞比率（M％）和PLT受血镉浓度影响大;偏回归系数经检验有显著性意义。线性相关性分析显示,小儿血铅浓度与血镉浓度、血钙浓度的Pearson相关系数大,分别为0．28、-0．13,钙浓度与铁浓度相关系数为-0．28,P值均小于0．05。结论小儿外周血液RBC、Hb、PLT数量的波动与血液中金属元素间相互影响所形成的浓度变化密切相关。     

21世纪规则的改革对我国少儿乒乓球运动的影响

通过对乒乓球国际规则的演变对乒乓球技术、战术和比赛的影响作了简略分析研究,结论表明：新规则的出台对我国少年乒乓球技战术训、身体训练练和心理训练都有不同程度的影响,为了适应规则的变化,应在少儿训练阶段,抓好全面性技术训练和身体训练,不断地创新、发挥自身的优势和特长,以培养适应当代乒坛发展趋势的优秀后备人才。     

Radial segregation due to weak convection in a floating zone

The influence of weak convection, caused by surface tension forces, on radial dopant segregation occurring in crystals grown under microgravity conditions is studied numerically. The geometry considered corresponds to a floating-zone configuration with partially coated melt surfaces consisting of small evenly distributed spots of free surfaces. In order to distinguish dopant distribution due to weak convection clearly from distribution due to diffusion the spots only cover one quarter of the periphery. Thus, surface tension-driven convection is allowed only over one quarter of the floating-zone configuration resulting in an asymmetric dopant distribution. The percentage of free surfaces present is varied in order to alter the Marangoni flow rates. The maximum dopant concentration due to radial segregation is plotted as a function of a certain convection level. The results of the present numerical study are supposed to be used to design corresponding space experiments launched at the end of the year 2000.     

Crystal growth and characterization of the CMR compound La1.2(Sr,Ca)1.8Mn2O7

High-quality centimeter-sized single crystals of La_1.2Sr_1.8−yCa_yMn₂O₇ (0.0y0.2) were successfully grown using a floating zone method associated with an image furnace. We present the growth conditions together with a characterization of the single crystals by means of optical and electron microscopy, EDX and ICPAES analysis, DTA-TGA measurements and redox titration, X-ray powder diffraction, Laue X-ray back-reflection and neutron diffraction. We also stress the main aspects of the complex thermodynamical and kinetic behaviors of these compounds.     

312例儿童发钙含量测定结果分析

于１９９６年５－６月，对本地区农村儿童随机抽样３１２例，进行发钙含量的测定，共测定３１２人，缺钙率７０．５１％，结果表明，儿童缺钙不仅在婴幼儿时期、在整个儿童生长发育时期均存在着缺钙现象，尤其在学龄前儿童更普遍。为了提高儿童健康素质，建议给儿童长期补钙，而且要早补。     

大庆油田水平井漂浮下套管技术研究

在油田开发中、后期,水平井钻井技术对剩余油挖潜举足轻重,是提高原油采收率及开发低渗透油层的重要手段,可降低综合成本、环境污染风险,减少生产占地,有效开发低效储量,提升油气田的产能和开发效益。目前大庆油田水平井随着水平段加长,导致套管下入困难,施工时被迫减少套管扶正器的数量,使套管居中度达不到设计要求,固井质量差。针对这些问题开展了相关技术研究,研制配套了系列工具并形成了一套适合大庆油田水平井漂浮下套管工艺技术,目前现场应用115口井,应用效果良好,提高了套管下入时效及固井质量。     

Growth of laser single-crystals Er:YVO4 by floating zone method

High optical quality Er³⁺:YVO₄ laser crystals have been grown by using the floating zone method (FZ). The spectroscopic properties and 3 μm lasing of Er³⁺:YVO₄ were investigated. It is found that the Er³⁺ concentration has a negative effect on the emission of the transition ⁴I_13/2→⁴I_15/2(1.55 μm ), and a positive effect on that of the ⁴I_11/2→⁴I_13/2 transition (2.68 μm). With direct upper-state pumping and a plane-concave cavity a self-terminating laser was achieved at the wavelength of 2.724 μm in the 30 at% Er³⁺ doped sample.     

海口市正常儿童头发中四种微量元素含量

用电感耦合等离子体发射光谱法（ＩＣＰ－ＡＥＳ），测定了海口市２６６例正常儿童头发中锌、铁、阵、铜四种微量元素的含量，计算出海口市儿童四各微量元素的正常范围。并与其它地区文献报道值进行了比较。     

A hypersingular integral equation for the floating body problem

A new boundary integral equation formulation for the floating body problem, which is defined on a bounded domain and includes a hypersingular and a nonlocal part, is proved to satisfy a Gärding inequality. Under the assunlption of uniqueness it is shown, that an approximating sequence of related semidiscrete integral operators is uniformly bounded invertible.     

肾病综合症、过敏性紫癜患儿血清原中铅含量研究

采用原子吸收光谱法，测定了肾病综合症、过敏性紫癜患儿血清和尿中铅含量，均高于近期国内外报道允许正常值，给临床治疗和诊断提供了一个新的研究途径。