N,N-二甲基甲酰胺中电沉积制备镁镍储氢合金

采用恒电位沉积法, 选用适宜的添加剂和络合剂, 成功地从N,N-二甲基甲酰胺(DMF)中沉积出致密的黑色Mg-Ni储氢合金膜. 并初步探讨了其共沉积机理. XRD显示沉积层中含有非晶态Mg-Ni相和微晶态Mg相. SEM图及相应能谱图分析表明合金颗粒以团聚状态存在, 合金成分不是很均匀. AAS分析表明沉积合金中Mg的原子摩尔分数达27.3%. LAND电池测试系统测得所镀合金膜的放电比容量最高为172.4 mAh/g.     

Creation of highly functional thin films using electrochemical nanotechnology

This overview describes the results of our recent study of the application of electrochemical nanotechnology to the fabrication of magnetic recording materials, interconnects in ultra-large-scale integrated (ULSI) devices, energy storage materials, and on-chip biosensors. It is important to note that electrochemical processes play significant roles in developing and fabrication such sophisticated materials and devices. In the field of magnetic recording, electrodeposition methods for preparing CoNiFe and CoFe soft magnetic thin films with a high saturation magnetic flux density were newly developed, and the significant issues for obtaining those films are highlighted. In the area of ULSI interconnects, we developed a technique using a self-assembled monolayer (SAM) for direct bonding of the interconnect layer to SiO2, and proposed a novel electroless deposition method for fabricating a diffusion barrier layer. In the field of batteries, electrodeposited SnNi alloy was proposed as a future anode material for Li batteries, and electrochemical MEMS processes were shown to be useful for fabricating micro-sized direct methanol fuel cells (DMFCs) as portable batteries for electronics applications. In the area of chemical sensors, we developed a new process for fabricating field effect transistors (FETs) modified with SAMs for on-chip biosensing applications.     

Topical Problems in the Biosynthesis of Red Blood Pigment

Uroporphyrinogen III plays a key role in the biosynthesis of heme, the red pigment of blood. In vivo studies with specifically ¹⁴C- and ³H-labeled precursors have revealed that the formation uroporphyrinogen III in the organism follows several primary and subsidiary pathways. Model experiments on the pattern of biosynthesis have led to simple and effective methods of synthesizing uroporphyrin analogs and have shown that their production is strongly favored thermodynamically. The biologically porphyrins important thus available permit a mechanistic explanation of the light-induced dermatoses in porphyria diseases and suggest promising medical applications in diagnosis and therapy.     

Analysis of selected pesticides and alkylphenols in human cord blood by gas chromatograph-mass spectrometer

A total of seven pesticides and eight alkylphenols were monitored using this method for the determination of their trace levels in human cord blood. The pesticides are lindane, diazinon, α-endosulfan, β-endosulfan, endosulfan sulfate, chlorpyrifos and endrin; while the alkylphenols are 4-n-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol, 4-t-octylphenol, 4-n-heptylphenol, nonylphenol, 4-n-octylphenol and bisphenol A. The pesticides and alkylphenols in the cord blood samples were extracted with solid phase extraction IST C18 cartridges and analyzed by selected ion monitoring mode using quadrapole detector in Shimadzu QP-5000 gas chromatograph-mass spectrometer. Trace levels of pesticide and alkylphenols in the range of non-detectable to 15.17 ng ml⁻¹, were detected in the human cord blood samples. This technique of monitoring the levels of endocrine-disruptors in blood samples is consistent, reliable and cost effective while reducing wastage of time and solvents.     

应用单细胞微凝胶电泳技术研究氯化镉对人血淋巴细胞DNA的损伤效应

详细介绍了单细胞微凝胶电泳（ＳＣＧ）技术的原理和操作过程，并应用该技术研究了氯化镉（ＣｄＣｌ２）对人血淋巴细胞ＤＮＡ的损伤效应，结果表明，ＣｄＣｌ２能引起细胞ＤＮＡ迁移长度增加，且呈显著的剂量效应关系，对未处理对照细胞的ＤＮＡ迁移的原因及ＳＣＧ实验操作过程中应注意的事项也进行了讨论。     

Preconcentration and Separation Procedures for the Spectrochemical Determination of Platinum and Palladium

Low concentrations of Pt and Pd in industrial (µgg^–1 level) and environmental samples (ngg^–1 level) together with the complexity of the matrix causing many interferences during the determination of noble metals often require elaboration and application of pre-concentration/matrix separation procedures before detection of the analyte. Different pre-concentration/matrix separation procedures applied prior to the determination of Pt and Pd by atomic spectrometric techniques are reviewed and critically compared taking into account potential interferences. The methods studied are divided into 5 groups including precipitation and coprecipitation, liquid–liquid extraction, solid phase extraction, electrochemical pre-concentration and biosorption. The main analytical problems occuring during sample preparation and storage are discussed.     

On-line SFE-GC for determination of PCBs in human milk and blood serum

On-line coupled supercritical fluid extraction and gas chromatography (SFE-GC) has been utilized for the determination of PCBs and other organochlorine compounds in human milk and blood serum. The procedure involved preconcentration of the sample on C₁₈-silica sorbent in an extraction cell: after precipitation of the proteins up to 20 ml of human milk was concentrated on 0.5 g of sorbent. Serum (up to 5 ml) was applied to the C₁₈ material without pretreatment. Basic alumina was utilized as a selective adsorbent for lipids in the on-line SFE-GC system. The method was used to analyze milk and serum spiked with 0.5 and 10 ng of Aroclor 1260 and the results compared with those obtained by liquid–liquid extraction of serum.     

Crystal structure of Mg0.65Sc0.35Dx deuterides studied by X-ray and neutron powder diffraction

The structural properties of the Mg_0.65Sc_0.35D_x deuterides have been investigated by X-ray and neutron powder diffraction at different deuterium content (0?x?2.2 D/f.u.). The metallic phase adopts a pseudo-CsCl structure (Pm-3m space group (SG); a=3.5921(2) Å) that transforms upon hydrogenation into a face centered cubic (FCC) phase involving an elongation of the c-axis, a shrinkage of the a-axis and a re-ordering of the metallic atoms. The fully hydrided compound (2.2 D/f.u.) adopts a cubic structure (Fm-3m SG; a=4.8087(7) Å) and deuterium is located in fully occupied tetrahedral sites and partially filled (24%) octahedral sites. Upon desorption, a two-phase domain appears with coexistence of a hydrogen-rich (1.55 D/f.u.) and a hydrogen-poor (0.85 D/f.u.) phase (Fm-3m SG; a=4.7598(3) and 4.6936(3) Å, respectively). All deuterium atoms are located in the tetrahedral sites with different occupancy factors: 77% for the H-rich phase and 43% for the H-poor phase. The appearance of a plateau in the pressure-composition-isotherm curve measured at 573 K confirms this two-phase behavior. The structural properties of the Mg_0.65Sc_0.35D_x system are discussed and compared with other body centered cubic (BCC) alloys adopting the same structure.     

低于300℃时两种氧化铈材料对稀燃阶段NOx存储性能的影响

研究了低于300 ℃时两种氧化铈对稀燃阶段NO_x存储性能的影响,催化剂由2%（w）Pt/Al₂O₃（PA）与CeO₂-X（X=S,I）机械混合制备. X射线衍射（XRD）,BET表面积和扫描电子显微镜（SEM）用于表征材料的物理结构. X射线光电子能谱（XPS）和H₂程序升温还原（H₂-TPR）用于表面Ce³⁺和活性氧定量. 原位漫反射傅里叶变换红外光谱（in-situ DRIFTS）用于分析表面NO_x吸附物种. 相比于CeO₂-I,CeO₂-S 具有优良的物理化学性能,包括高比表面积、丰富的空隙结构、较高的抗老化能力及表面Ce³⁺浓度. 因而,Pt/Al₂O₃+CeO₂-S 表现出优异的NO_x存储能力. 此外,PA+CeO₂-X（X=S,I）上存在Pt 与CeO₂之间的相互作用,可提高表面氧物种的活性进而促进NO氧化及NO_x存储. PA+CeO₂-S上的这种相互作用要强于PA+CeO₂-I. 研究表明,表面Ce³⁺浓度和活性氧含量对NO_x存储起到重要作用. 然而经过水热处理后,Pt 与老化的氧化铈（ACS,ACI）之间的相互作用降低,并且两种氧化铈NO_x存储性能显著下降. 另外,与PA+ACS（ACI）相比,PA+PACS（PACI）样品NO_x存储能力得到改善,这归因于表面氧物种活性增加能促进硝酸盐的形成.     

Effect of hydrocolloids on starch thermal transitions,as measured by DSC

Differential scanning calorimetry (DSC) was used to analyze the influence of different hydrocolloids (xanthan, guar, and locust bean gums, carboxymethylcellulose and sodium alginate) on the gelatinization of corn starch in systems with starch concentration ranging between 0.1 and 0.7 g starch/g mixture. The reduction of available water produced a shift in gelatinization temperature, especially of the conclusion temperature. The effect was more marked for ionic hydrocolloids. The influence of hydrocolloids on glass transition temperature (T _g) of gelatinized starch suspensions and on the glass transition temperature of the maximally freeze-concentrated solute/unfrozen water matrix (T _g) was also studied.T _g onset values ranged between –4.5 and –5.5C for corn starch pastes with and without hydrocolloids. Those hydrocolloids that increased the viscosity of the unfrozen matrix inhibited additional ice formation during thawing (devitrification).Starch concentration and final heating temperature were found to be relevant factors affecting the kinetics of amylopectin retrogradation during frozen storage at –4C. Xanthan gum failed to prevent amylopectin retrogradation; this observation could be attributed to the fact that gums act outside the starch granule, while amylopectin retrogradation takes place within the granule.