O_2/Si(100)-2×1重构表面相互作用过程的动力学研究

对双原子分子O2与Si（100）－2×1重构表面的相互作用过程进行了动力学研究。建立了相互作用系统的LEPS势能超曲面，并在此基础上采用准经典轨迹方法计算了不同特征吸附位上的分子运动轨迹，得到了与理想表面模型相比更为合理的表面吸附特性。     

O_2/Si(100)非重构表面相互作用过程的准经典轨迹研究

采用准经典轨迹计算方法对双原子分子O2与非重构Si（100）理想表面的散射过程进行了动力学研究。计算结果解释了氧分子与半导体表面相互作用中的能量传递机理，验证了前面工作所得到的LEPS半经验模型势的合理性。     

N_2/W(110)散射过程的准经典轨迹研究

本文对双原子分子与固体表面相互作用系统进行了初步的动力学计算。其中表面作为具有波纹度的刚性表面进行处理,即忽略了气体分子与表面的能量传递。以N_2-W(110)系统为例,在已构造的分子-表面作用势基础上,用准经典轨迹(QCT)的方法进行了计算。在刚性表面的近似下,仍可观察到分子在表面上的离解、选择性吸附等现象。     

O2／Si（100）非重构表面相互作用过程的准经典轨迹研究

采用准经典轨迹计算方法对双原子分子Ｏ２与非重构Ｓｉ（１００）理想表面的散射过程进行了动力学研究。计算结果解释了氧分子与半导体表面相互作用中的能量传递机理，验证了前面工作所得到的ＬＥＰＳ半经验模型势的合理性。     

碳球负载四氧化三铁（Fe3O4／CNs）吸附Cu（Ⅱ）的性能研究米

利用水热法合成碳球（CNs）,原位生长四氧化三铁（Fe3O4）,通过SEM、XRD和FT—IR进行表征,研究碳球负载四氧化三铁（Fe3O4／CNs）对Cu（Ⅱ）的吸附性能,结果表明,当pH=6时,Fe3O4／CNs对Cu（Ⅱ）的去除率最大,吸附符合Langmuir等温方程,最大吸附量为44．08mgg。吸附动力学表明,Fe3O4／CNs对Cu（Ⅱ）的吸附符合准二级动力学方程。     

O_2/Si(100)非重构表面LEPS相互作用势模型

对双原子分子O2与非重构Si（100）表面相互作用的LEPS半经验势模型进行了研究，其中表面作为具有波纹度的刚性表面进行处理。确立了系统的势能超曲面，得到的表面吸附特性与P．V．Smith等人基于ASED－MO方法的研究结果进行了定量对比分析。对不同入射条件下的分子－表面相互作用势也进行了研究。     

对向靶溅射高炮和磁化强度(Fe,Ti)-N薄膜

本实验用对向靶溅射仪分别在Si（100），NaCl单晶衬底上成功地制备出具有高炮和磁化强度的（Fe，Ti）－N薄膜，研究了氮气分压和衬底温度对薄膜结构与磁性的影响。氮气分压为0．04～0．07Pa，衬底温度为100～150℃时，有利于Fe_(16)N_2相的形成，在此条件下制备的（Fe，Ti）－N薄膜的饱和磁化强度为2．3～2．46T，超过纯Fe的饱和磁化强度值。     

铸钢中(Mn,Fe)S单晶体的发现与研究

用SEM505扫描电子显微镜观察并发现了ZG25钢铸件皮下显微气孔壁上（Mn，Fe）S单晶体的自然形态。平衡态面心立方（Mn，Fe）S单晶体是由八个{111}晶面和六个{100}晶面组成的十四面体。（Mn，Fe）S单晶体自然形态是Oh—m3m类立方晶系对称图形新发现的典型实例。填补了晶体学单晶十四面体晶形的空白。     

花生壳对Cu(Ⅱ)的吸附特性

花生壳资源丰富,吸附重金属离子有较大优势。为此,研究了花生壳对溶液中Cu(Ⅱ)的吸附特性,考察了溶液pH值、Cu(Ⅱ)初始浓度和吸附时间对吸附率的影响。结果表明:溶液pH值、Cu(Ⅱ)初始浓度和吸附时间对花生壳吸附Cu(Ⅱ)有较大影响,吸附平衡时间约为120 min;花生壳对Cu(Ⅱ)的吸附过程符合准二级吸附动力学模型和Langmuir等温吸附模型,不同温度下吸附过程的ΔG0<0,ΔH0>0,ΔS0>0,表明花生壳对Cu(Ⅱ)的吸附过程是一个自发的吸热过程。     

交联P（St-r-AA）包覆Fe3O4粒子的制备及对Cu2＋的吸附

用乳液聚合的方法合成了交联P（St-r-AA）包覆的Fe3O4粒子,研究了该类粒子对Cu2＋离子的吸附性能。透射电镜（TEM）表明,交联的P（St-r-AA）包覆的Fe3O4磁性粒子粒径约100 nm;X射线衍射（XRD）分析表明,磁性粒子中磁性物质为尖晶石结构的Fe3O4;红外光谱（FT-IR）表明,Fe3O4表面的...     

Study of the removal of mercury(II) and chromium(VI) from aqueous solutions by Moroccan stevensite

The objective of the present study was to investigate the adsorption of the heavy metals mercury(II) and chromium(VI), from aqueous solutions, onto Moroccan stevensite. A mineralogical and physicochemical characterization of natural stevensite was carried out. In order to improve the adsorption capacity of stevensite for Cr(VI), a preparation of stevensite was carried out. It consists in saturating the stevensite by ferrous iron Fe(II) and reducing the total Fe by Na(2)S(2)O(4). Then, the adsorption experiments were studied in batch reactors at 25+/-3 degrees C. The influence of the pH solution on the Cr(VI) and Hg(II) adsorption was studied in the pH range of 1.5-7.0. The optimum pH for the Cr(VI) adsorption is in the pH range of 2.0-5.0 while that of Hg(II) is at the pH values above 4.0. The adsorption kinetics were tested by a pseudo-second-order model. The adsorption rate of Hg(II) is 54.35 mmol kg(-1)min(-1) and that of Cr(VI) is 7.21 mmol kg(-1)min(-1). The adsorption equilibrium time for Hg(II) and Cr(VI) was reached within 2 and 12 h, respectively. The adsorption isotherms were described by the Dubinin-Radushkevich model. The maximal adsorption capacity for Cr(VI) increases from 13.7 (raw stevensite) to 48.86 mmol kg(-1) (modified stevensite) while that of Hg(II) decreases from 205.8 to 166.9 mmol kg(-1). The mechanism of Hg(II) and Cr(VI) adsorption was discussed.     

Comparative study of adsorption properties of Turkish fly ashes. II. The case of chromium (VI) and cadmium (II)

The purpose of the study described in this paper was to compare the removal of Cr(VI) and Cd(II) from an aqueous solution using two different Turkish fly ashes; Afsin-Elbistan and Seyitomer as adsorbents. The influence of four parameters (contact time, solution pH, initial metal concentration in solution and ash quality) on the removal at 20+/-2 degrees C was studied. Fly ashes were found to have a higher adsorption capacity for the adsorption of Cd(II) as compared to Cr(VI) and both Cr(VI) and Cd(II) required an equilibrium time of 2h. The adsorption of Cr(VI) was higher at pH 4.0 for Afsin-Elbistan fly ash (25.46%) and pH 3.0 for Seyitomer fly ash (30.91%) while Cd(II) was adsorbed to a greater extent (98.43% for Afsin-Elbistan fly ash and 65.24% for Seyitomer fly ash) at pH 7.0. The adsorption of Cd(II) increased with an increase in the concentrations of these metals in solution while Cr(VI) adsorption decreased by both fly ashes. The lime (crystalline CaO) content in fly ash seemed to be a significant factor in influencing Cr(VI) and Cd(II) ions removal. The linear forms of the Langmuir and Freundlich equations were utilised for experiments with metal concentrations of 55+/-2mg/l for Cr(VI) and 6+/-0.2mg/l for Cd(II) as functions of solution pH (3.0-8.0). The adsorption of Cr(VI) on both fly ashes was not described by both the Langmuir and Freundlich isotherms while Cd(II) adsorption on both fly ashes satisfied only the Langmuir isotherm model. The adsorption capacities of both fly ashes were nearly three times less than that of activated carbon for the removal of Cr(VI) while Afsin-Elbistan fly ash with high-calcium content was as effective as activated carbon for the removal of Cd(II). Therefore, there are possibilities for use the adsorption of Cd(II) ions onto fly ash with high-calcium content in practical applications in Turkey.     

Reaction of ozone with Np(IV) and Pu(IV) oxalates in water

The reaction of the ozone–oxygen mixture with aqueous suspensions of Np(IV) and Pu(IV) oxalates was studied. Both metal cations and oxalate anions are oxidized in the process. The final products are Np(VI) and Pu(VI) hydroxides. The composition of Np(VI) hydroxide was confirmed by X-ray diffraction analysis. Oxidation of Np(IV) oxalate with oxygen leads to the accumulation of Np(V) oxalate and oxalic acid in the solution. At incomplete oxidation of Np(IV) oxalate with ozone in water, Np(V) is also accumulated. Heating considerably accelerates the ozonation. The possible reaction mechanism is briefly discussed. The Np(V) and Np(VI) ions participate in the catalytic cycle of the decomposition of oxalate ions with ozone.     

Stability of Pu(VI) and Pu(V) in aqueous formate solutions

The behavior of Pu(VI), Pu(V), and Pu(IV) in K(Li,Na)HCO₂ and HCOOH + Li(Na)HCO₂ solutions was studied by spectrophotometry. Changes in the spectra of a Pu(VI) solution, observed on adding alkali metal formates, suggest formation of Pu(VI) formate complexes. Changes in the absorption spectra of Pu(V), observed with an increase in the concentration of LiHCO₂ or NaHCO₂, suggest the appearance of Pu(V) formate complexes. The absorption spectra of Pu(IV) indicate that, in a wide range of formate concentrations, the composition of the Pu(IV) formate complexes under the examined conditions is constant. The Pu(VI) content in formate solutions decreases at a rate exceeding the rate of the Pu(VI) disappearance in 0.5–2 M HClO₄ under the action of the ²³⁹Pu α-radiation. The tendency of Pu(V) to reduction and disproportionation in formate solutions depends in a complex fashion on the formate ion concentration and kind of the alkali metal. The kinetics of the Pu(V) consumption in HCOOH + Li(Na)HCO₂ solutions was studied. The reaction starts with the formation of a Pu(V) formate complex, which interacts with Pu(V) aqua ions and Pu(V) formate complex to form dimers, with their subsequent protonation and transformation into Pu(VI) and Pu(IV).     

Activity concentrations of 226Ra and 228Ra in drilled well water in Finland

The activity concentrations of (226)Ra and (228)Ra in drinking water were determined in water samples from 176 drilled wells. (226)Ra activity concentrations were in the range of <0.01-1.0 Bq l(-1) and (228)Ra activity concentrations in the range of <0.03-0.3 Bq l(-1). The mean activity concentration of (226)Ra and (228)Ra were 0.041 and 0.034 Bq l(-1), respectively. High radium activity concentrations in drinking water were rare. Only 2-4% of the drilled wells exceeded a (226)Ra concentration of 0.5 Bq l(-1) and 1-2% of the wells exceeded a (228)Ra concentration of 0.2 Bq l(-1). These are the activity concentrations that cause a 0.1 mSv annual effective dose for users of drinking water. The maximum annual effective doses from (226)Ra and (228)Ra for users of drilled wells were 0.21 mSv, and 0.16 mSv respectively. The elevated activity concentrations of (226)Ra and (228)Ra did not occur simultaneously in the same groundwaters and the correlation between (226)Ra and (228)Ra was small.     

Adsorption of Pb(II) and Pb(II)-citric acid on sawdust activated carbon: Kinetic and equilibrium isotherm studies

The removal of Pb(II) and Pb(II)-citric acid (Pb(II)-CA) from aqueous solutions by sawdust activated carbon (SDAC) was investigated. The higher adsorptive removal of Pb(II) from aqueous solutions containing Pb(II)-CA than Pb(II) only was observed due to the presence of CA in the former system. The mechanism of adsorption process was studied by conducting pH as well as kinetic studies. Batch adsorption experiments were conducted to study the effect of adsorbent dose, initial concentration and temperature for the removal of Pb(II) from Pb(II) only and Pb(II)-CA aqueous systems. The adsorption was maximum for the initial pH in the range of 6.5-8.0 and 2.0-5.0 for Pb(II) and Pb(II)-CA, respectively. The solution pH, zero point charge (pH(zpc)) and species distribution of Pb(II) and Pb(II)-CA were found to play an important role in the adsorption of Pb(II) and Pb(II)-CA onto SDAC from water and wastewaters. SDAC exhibited very high adsorption potential for Pb(II) ions in presence of CA than when Pb(II) ions alone were present. The kinetic and equilibrium adsorption data were well modeled using pseudo-first-order kinetics and Langmuir isotherm model, respectively.     

La0.67Mg0.33Ni3.0-xAlx(x=0～0.3)贮氢合金的相结构及电化学性能的研究

研究了Al元素对合金La0．67Mg0．33Ni3．0中Ni的替代对舍金的微观组织结构及电化学性能的影响。X射线衍射(XRD)分析结果表明La0．67Mg0．33Ni3．0合金由PuNi3型(La，Mg)Ni3相和Ce2Ni2型(La，Mg)2Ni7相组成，Al元素加入后，开始出现CaCu5型LaNi5相，随着Al含量的增加，LaNi5相逐渐增多，当x=0．3时，LaNi5相成为合金的主相，合金La0．67Mg0．33Ni3．0中Al的X荧光元素面分布图像表明了Al元素主要进入LaNi5相中，说明Al是一种LaNi5相形成元素；电化学测试表明，随着Al含量的增加，合金的最大放电容量依次下降，4种合金的最大放电量分别为392、324、267和252mAh／g，活化次数变化不大(2～3次即可活化)，循环稳定性先增加后下降。     

Bioaccumulation of 210Po and 210Pb in cephalopods collected from Kudankulam (Southeastern coast of Gulf of Mannar, India) and assessment of dose in human beings

Activities of (210)Po and (210)Pb in various tissues of two common species of cephalopod molluscs (cuttlefishes) of Kudankulam coast were studied. Of all the tissues, (210)Po and (210)Pb were found accumulated more in the digestive gland, shell gland and intestine. Urotheuthis duvauceli accumulated more (210)Po and (210)Pb in certain organs when compared with Sepiella inermis. The activity ratio of (210)Po/(210)Pb fell within the range of 0.6-29.3 in the organs. The biological concentration factor for the organs ranged from 1.2×10(3) to 2×10(5) for (210)Po and 3.6×10(2) to 7.6×10(4) for (210)Pb. A significant variation in the accumulation of (210)Po and (210)Pb was noted between species, organs and seasons (p < 0.05). The whole-body internal dose rate due to (210)Po was 1.24 and 0.83 μGy h(-1) and it was 2×10(-3) and 3×10(-3) μGy h(-1) due to (210)Pb for both the species. The effective dose in humans due to (210)Po intake ranged from 96.3 to 376.6 μSv y(-1) and that of (210)Pb ranged from 35.2 to 105.7 μSv y(-1), respectively. The data generated will act as a reference database for these organisms of this coast in which a nuclear power station is under construction.     

Bactericidal properties of ZnO–Al2O3 composites formed from layered double hydroxide precursors

ZnO-Al(2)O(3) composites with different Zn/Al molar ratios (R) have been prepared using zinc-aluminium layered double hydroxides (LDHs) Zn( R )Al-CO(3) as precursor. The samples were characterized by XRD, ICP, EDX, EPR and FT-IR. The results show that ZnO is highly dispersed in all of the ZnO-Al(2)O(3) composites. Bactericidal experiments against Staphylococcus aureus ATCC 6538 and Bacillus subtilis var. niger ATCC 9372 were carried out by contacting the bacteria and spores with the ZnO-Al(2)O(3) composites. The composites all showed high bactericidal activity against Staphylococcus aureus ATCC 6538, and the bactericidal efficiency against Bacillus subtilis var. niger ATCC 9372 increased with increasing content of ZnO. The mechanism of bactericidal activity of ZnO-Al(2)O(3) has also been investigated. It is suggested that highly active O(2) (-) and *OH species generated on the surface of ZnO-Al(2)O(3) particles react with the peptide linkages in the cell walls of bacteria or spores resulting in their destruction.     

Radioactivity of coals and ashes from Catalağzi coal-fired power plant in Turkey

The ?atala?z? coal-fired power plant (CFPP) is the Turkish CFPP that uses the hard coals produced in Zonguldak, located in the West Black Sea region of the country. Gamma-ray spectrometry was used to determine (226)Ra, (232)Th and (40)K contents in pulverised coal, bottom ash and fly ash samples. The natural radionuclide concentrations in pulverised coal ranged from 29 to 61 Bq kg(-1) for (226)Ra, from 32 to 55 Bq kg(-1) for (232)Th and from 229 to 414 Bq kg(-1) for (40)K. The fly ash fraction gave concentrations ranging from 80 to 98 Bq kg(-1) for (226)Ra, from 64 to 85 Bq kg(-1) for Th and from 754 to 992 Bq kg(-1) for (40)K, respectively. The enrichment factors from coal to fly ashes are 1.7, 2.24 and 2.6 for (232)Th, (226)Ra and (40)K, respectively. Therefore, it is advisable to monitor the environmental impact of the power plant.