Charge-trapping characteristics of Al2O3/Cu/Al2O3 nanolaminate structures prepared through atomic layer deposition

The nanolaminate Al2O3/Cu/Al2O3 structures were constructed on p-type Si (001) substrates using atomic layer deposition (ALD) process with the aim to fabricating nonvolatile charge-trap memories. Low temperature Cu thin layers were deposited through plasma-enhanced atomic layre depositon of Cu aminoalkoxide (Cu(dmamb)2) combined with hydrogen plasma and Al2O3 layers were prepared by thermal atomic layer deposition of trimethylaluminum (TMA) combined with H2O. Nonvolatile features were confirmed using capacitance-voltage (C-V) measurements. The copper film functions as a charge-trapping layer and the Al2O3 thin layers were employed as tunneling and control oxide layers. Line shapes and binding energies of Cu metal and the thin layer of 6 nm Cu in nanolaminate structures were observed in the X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (TEM) image. The V(FB) shift width of the Al2O3 (28 nm)/Cu (6 nm)/Al2O3 (4.2 nm)/Si laminate structure is found to be 4.75 V in voltage sweeping between -10 and +10 V, leading to the trap density of 1.68 x 10(18) cm(-3).     

Decolorization kinetics of Procion H-exl dyes from textile dyeing using Fenton-like reactions

The decolorization kinetics of three commercially used Procion H-exl dyes was studied using a Fenton-like reagent. The effect of the major system parameters (pH, concentration of H(2)O(2) and Fe(3+) and initial dye concentration) on the kinetics was determined. For comparison, the effect of the use of UV irradiated Fenton-like reagent and of Fenton reagent on the kinetics was also examined. In addition, mineralization rates and the biodegradability improvement as well as the effect of the addition of Cl(-), CO(3)(2-) or HCO(3)(-) on the decolorization rates was studied. The reactions were carried out in a 300 ml stirred cylindrical reactor with the capability of UV irradiation. The dye half-life time goes through a minimum with respect to the solution pH between 3 and 4. It also exhibits a broad minimum with respect to Fe(3+) and H(2)O(2) at molar ratios of H(2)O(2)/Fe(3+) from about 100 to 10. The addition of CO(3)(2-) and HCO(3)(-) substantially reduces the decolorization rates, while this effect is significantly less pronounced with Cl(-). At an optimum range of parameters, the mineralization rate (TOC reduction) is very slow for the Fenton-like process (TOC decrease from an initial 49.5 to 41.1 mg/l after 30 min and to only 35.2 mg/l after 600 min), but it increases significantly for the photo-Fenton-like process (to TOC values of 39.7 and 11.4 mg/l, respectively). The biodegradability, as expressed by the BOD/COD ratio, increases significantly from an initial value of 0.11-0.55 for the Fenton-like and to 0.72 for the photo-Fenton-like processes.     

Kinetics of Fe(3)O(4)-CoO/Al(2)O(3) catalytic ozonation of the herbicide 2-(2,4-dichlorophenoxy) propionic acid

The presence of Fe(3)O(4)-CoO/Al(2)O(3) can improve degradation efficiency significantly during the ozonation of the herbicide 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP). The main factors affecting degradation efficiency, such as pH, the catalyst concentration and addition of the scavenger, were investigated. The kinetics of the catalytic ozonation are also discussed. The results indicate that two factors, the oxidation after adsorption of 2,4-DP and the oxidation of hydroxyl radicals (OH), lead to a great enhancement in ozonation efficiency during the catalytic ozonation of 2,4-DP in the presence of Fe(3)O(4)-CoO/Al(2)O(3), in which the oxidation of the OH plays an important role. Under controlled conditions, the apparent reaction rate constants for the degradation of 2,4-DP were determined to be 2.567 × 10(-4)s(-1) for O(3) and 1.840 × 10(-3)s(-1) for O(3)/Fe(3)O(4)-CoO/Al(2)O(3). The results from the analysis of the reaction kinetics using the relative method showed that O(3)/Fe(3)O(4)-CoO/Al(2)O(3) possessed a larger R(ct) (R(ct) is defined as the ratio of the ·OH exposure to the O(3) exposure, R(ct) = ∫C(t)(OH) dt/C(t)O(3)dt) than O(3), indicating that O(3)/Fe(3)O(4)-CoO/Al(2)O(3) produced more hydroxyl radicals.     

Photodegradation of direct yellow-12 using UV/H2O2/Fe2+

A detailed investigation of photodegradation of direct yellow-12 (DY12) using UV/H(2)O(2)/Fe(2+) has been carried out in a photochemical reactor. Experiments studied degradation as a function of concentration, decolorization and reduction in chemical oxygen demand (COD). The effect of operating parameters, such as UV, pH, amount of Fenton's reagent (H(2)O(2) and FeSO(4)), and amount of DY12 dye has also been determined. It has been observed that simultaneous utilization of UV irradiation with Fenton's reagent increases the degradation rate of DY12 dye. The dye quickly losses its color and there is an appreciable decrease in COD value, indicating that the dissolved organic have been oxidized. The kinetics of degradation of the dye in dilute aqueous solutions follows pseudo-first order kinetics. Final products detected at the end of the reaction include NO(3)(-), NO(2)(-), N(2)O, NO(2), SO(2), CO(2) and CO. Results indicate that dye degradation is dependent upon pH, UV-intensity, concentration of Fenton's reagent and dye. Acidic pH has been found to be more suitable in comparison to neutral and alkaline. The optimum concentration of Fenton's reagent (H(2)O(2)/Fe(2+)) was found as 1500/500 mg l(-1) for 50 mg l(-1) DY12 dye in water at pH 4. The results indicate that the treatment of DY12 dye wastewater with UV/Fe(2+)/H(2)O(2) system is efficient.     

Ametryn degradation in the ultraviolet (UV) irradiation/hydrogen peroxide (H2O2) treatment

Ultraviolet (UV) irradiation (253.7nm) in the presence of hydrogen peroxide (H(2)O(2)) was used to decompose aqueous ametryn. The concentrations of ametryn were measured with time under various experiment conditions. The investigated factors included H(2)O(2) dosages, initial pH, initial ametryn concentrations, and a variety of inorganic anions. Results showed that ametryn degradation in UV/H(2)O(2) process was a pseudo-first-order reaction. Removal rates of ametryn were greatly affected by H(2)O(2) dosage and initial concentrations of ametryn, but appeared to be slightly influenced by initial pH. Furthermore, we investigated the effects of four anions (SO(4)(2-), Cl(-), HCO(3)(-), and CO(3)(2-)) on ametryn degradation by UV/H(2)O(2). The impact of SO(4)(2-) seemed to be insignificant; however, Cl(-), HCO(3)(-), and CO(3)(2-) considerably slowed down the degradation rate because they could strongly scavenge hydroxyl radicals (OH) produced during the UV/H(2)O(2) process. Finally, a preliminary cost analysis revealed that UV/H(2)O(2) process was more cost-effective than the UV alone in removal of ametryn from water.     

Adsorption characteristics of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto chitosan/clinoptilolite sorbents

Adsorption features of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto a novel chitosan/clinoptilolite (CS/CPL) composite as beads have been investigated compared with chitosan cross-linked with epichlorohydrin. The effects of contact time, the initial metal ion concentration, sorbent mass and temperature on the adsorption capacity of the CS-based sorbents were investigated. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Sips model. The maximum experimental adsorption capacities were 328.32 mg Th(4+)/g composite, and 408.62 mg UO(2)(2+)/g composite. The overall adsorption tendency of CS/CPL composite toward UO(2)(2+) and Th(4+) radiocations in the presence of Cu(2+), Fe(2+) and Al(3+), under competitive conditions, followed the order: Cu(2+)>UO(2)(2+)>Fe(2+)>Al(3+), and Cu(2+)>Th(4+)>Fe(2+)>Al(3+), respectively. The negative values of Gibbs free energy of adsorption indicated the spontaneity of the adsorption of radioactive ions on both the CS/CPL composite and the cross-linked CS. The desorption level of UO(2)(2+) from the composite CS/CPL, by using 0.1M Na(2)CO(3), was around 92%, and that of Th(4+) ions, performed by 0.1M HCl, was around 85%, both values being higher than the desorption level of radiocations from the cross-linked CS, which were 89% and 83%, respectively.     

Degradation of n-butyl benzyl phthalate using TiO2/UV

n-Butyl benzyl phthalate (BBP) has been classified as endocrine disrupting compound and priority pollutant. Effects of TiO(2) dosage, pH, initial BBP concentration and co-existing substances on the degradation of BBP by TiO(2)/UV process were investigated. The optimal TiO(2) dosage and pH value for the BBP degradation were 2.0gL(-1) and 7.0, respectively. The degradation rate of BBP by TiO(2)/UV process could be fitted pseudo-first-order kinetics. The effects of co-existing substances on the degradation rate of BBP revealed that some anions (such as BrO(3)(-), ClO(4)(-) and Cr(2)O(7)(2-)) could enhance BBP degradation, and other anions would restrain BBP degradation. The sequence of inhibition was PO(4)(3-)>CO(3)(2-)>NO(3)(-)>SO(4)(2-)>Cl(-). The cations K(+), Na(+), Mg(2+) and Ca(2+) had the restrained effect on the BBP degradation, and the effect of Ca(2+) was the strongest among four cations tested. The organic compounds acetone and methanol decreased the degradation rate of BBP. The major intermediates of BBP degradation were identified as mono-butyl phthalate, mono-benzyl phthalate and phthalic acid, and a primary degradation mechanism was proposed.     

Photochemical mineralization of di-n-butyl phthalate with H2O2/Fe3+

This study evaluated the performance of photo-Fenton reaction initiated by the UV irradiation with H(2)O(2)/Fe(3+), denoted as UV/H(2)O(2)/Fe(3+), to decompose di-n-butyl phthalate (DBP) in the aqueous solution. The concentration of total organic carbon (TOC) was chosen as a mineralization index of the decomposition of DBP by the UV/H(2)O(2)/Fe(3+) process. A second-order kinetic model with respect to TOC was adequately adopted to represent the mineralization of DBP by the UV/H(2)O(2)/Fe(3+) process. The experimental results of this study suggested that the dosages with 4.74 x 10(-5) mol min(-1)L(-1) H(2)O(2) and initial Fe(3+) loading concentration of 4.50 x 10(-4) mol L(-1) in the solution at pH 3.0 with 120 microW cm(-2) UV (312 nm) provided the optimal operation conditions for the mineralization of DBP (5 mg L(-1)) yielding a 92.4% mineralization efficiency at 90 min reaction time.     

Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes

The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O(3)/UV radiation, H(2)O(2)/UV radiation, O(3)/H(2)O(2), O(3)/H(2)O(2)/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs. Single O(3) or UV did not result in perceptible decomposition of HAAs within the applied reaction time. O(3)/UV showed to be more suitable for the decomposition of DCAA and TCAA in water among the six methods of oxidation. Decomposition of DCAA was easier than TCAA by AOPs. For O(3)/UV in the semi-continuous mode, the effective utilization rate of ozone for HAA decomposition decreased with ozone addition. The kinetics of HAAs decomposition by O(3)/UV and the influence of coexistent humic acids and HCO(3)(-) on the decomposition process were investigated. The decomposition of the HAAs by the O(3)/UV accorded with the pseudo-first-order mode under the constant initial dissolved O(3) concentration and fixed UV radiation. The pseudo-first-order rate constant for the decomposition of DCAA was more than four times that for TCAA. Humic acids can cause the H(2)O(2) accumulation and the decrease in rate constants of HAAs decomposition in the O(3)/UV process. The rate constants for the decomposition of DCAA and TCAA decreased by 41.1% and 23.8%, respectively, when humic acids were added at a concentration of 1.2mgTOC/L. The rate constants decreased by 43.5% and 25.9%, respectively, at an HCO(3)(-) concentration of 1.0mmol/L.     

Comparison of adsorption equilibrium models for the study of CL-, NO3- and SO4(2-) removal from aqueous solutions by an anion exchange resin

The removal of chloride, nitrate and sulfate ions from aqueous solutions by a macroporous resin is studied through the ion exchange systems OH(-)/Cl(-), OH(-)/NO(3)(-), OH(-)/SO(4)(2-), and HCO(3)(-)/Cl(-), Cl(-)/NO(3)(-), Cl(-)/SO(4)(2-). They are investigated by means of Langmuir, Freundlich, Dubinin-Radushkevitch (D-R) and Dubinin-Astakhov (D-A) single-component adsorption isotherms. The sorption parameters and the fitting of the models are determined by nonlinear regression and discussed. The Langmuir model provides a fair estimation of the sorption capacity whatever the system under study, on the contrary to Freundlich and D-R models. The adsorption energies deduced from Dubinin and Langmuir isotherms are in good agreement, and the surface parameter of the D-A isotherm appears consistent. All models agree on the order of affinity OH(-)相似文献   

Photodegradation of 2-mercaptobenzothiazole in the gamma-Fe(2)O(3)/oxalate suspension under UVA light irradiation

The aim of this study is to investigate the effect of various factors on the photodegradation of organic pollutants in natural environment with co-existence of iron oxides and oxalic acid. 2-Mercaptobenzothiazole (MBT) was selected as a model pollutant, while gamma-Fe(2)O(3) was selected as iron oxide. The crystal structure and morphology of the prepared gamma-Fe(2)O(3) was determined by X-ray diffractograms (XRD) and scanning electron microscopy (SEM), respectively. The specific surface area was 14.36 m(2)/g by Brunauer-Emmett-Teller (BET) method. The adsorption behavior of gamma-Fe(2)O(3) was evaluated by Langmuir model. The effect of the dosage of iron oxide, initial concentration of oxalic acid (C(ox)(0)), initial pH value, the light intensity and additional transition metal cations on MBT photodegradation was investigated in the gamma-Fe(2)O(3)/oxalate suspension under UVA light irradiation. The optimal gamma-Fe(2)O(3) dosage was 0.4 g/L and the optimal C(ox)(0) was 0.8 mM with the UVA light intensity of 1800 mW/cm(2). And the optimal dosage of gamma-Fe(2)O(3) and C(ox)(0) for MBT degradation also depended strongly on the light intensity. The optimal gamma-Fe(2)O(3) dosage was 0.1, 0.25 and 0.4 g/L, and the optimal C(ox)(0) was 1.0, 0.8, and 0.8 mM with the light intensity of 600, 1200 and 1800 mW/cm(2), respectively. The optimal initial pH value was at 3.0. The additional transition metal cations including Cu(2+), Ni(2+) or Mn(2+) could significantly accelerate MBT degradation. This investigation will give a new insight to understanding the MBT photodegradation in natural environment.     

Numerical evaluation on heat transport characteristics between Al2O3 and ZnO materials in nanoscale situation

The aim of this article is to provide a systematic method to perform numerical evaluation on the cross-plane thermal conductivity of Al(2)O(3)/ZnO film interface. The Equilibrium Molecular Dynamics (EMD) simulations method is used to investigate the cross-plane thermal conductivity of Al(2)O(3)/ZnO film interface along the direction of Z axis at different equilibrium temperature and film interface thickness. The Buckingham two-body potential function and Green-Kubo linear response theory are used for modeling and calculation. The results show that the size effect is obvious. It implies the film interface thickness is 23.4-52 ? and the equilibrium temperature is 300-600 K. The cross section thermal conductivity of Al(2)O(3)/ZnO film interface increases with the increase of interface thickness, and decreases with the increase in equilibrium temperature.     

(TiB2+Al2O3)增强铜基复合材料的研究

研究了Cu-Al-TiO2-B2O3粉末在机械合金化和随后的烧结过程中结构的变化，结果表明：Cu-Al-TiO2-B2O3粉末通过机械合金化可以形成Cu(Ti,B）及Al2O3和少量的TiCu3粉末，Al2O3是通过机械合金化过程中的自维持反应形成的，采用Cu,Al,TiO2和B2O3作为原料，通过机械合金化和随后的加压烧结，可以制备性能较好的（TiB2 Al2O3）增强铜基复合材料。     

Optical evidence for reactive processes when embedding Cu nanoparticles in Al(2)O(3) by pulsed laser deposition

The optical response of nanocomposite thin films formed by Cu nanoparticles (NPs) embedded in amorphous aluminium oxide (Al(2)O(3)) prepared by pulsed laser deposition (PLD) in vacuum is studied in order to investigate the possible existence of reactive processes on the Cu NPs during their covering with Al(2)O(3). The study is performed as a function of the laser fluence on the Al(2)O(3) target (0.6-4.6?J?cm(-2)), while the laser fluence for Cu ablation is kept constant (1.8?J?cm(-2)). The structural analysis of the films shows that they are formed by a high density of NPs with average dimensions in the 4.9-5.9?nm range. The optical response of the films has been followed in situ by real-time reflectivity measurements at 633?nm and after deposition by transmission measurements as a function of wavelength around the surface plasmon resonance (SPR). For low laser fluences on the Al(2)O(3) target, the absorption spectrum is dominated by a well-defined SPR absorption band at 1.9?eV. As the laser fluence is increased, the intensity of the absorption band associated with the SPR decreases and shifts to 2.1?eV. The films deposited at low fluences contain metallic Cu NPs and, as the laser fluence increases sputtering of Cu from the NPs and mixing of the species from the Al(2)O(3) deposition with the Cu from the NPs surface takes place. The latter process leads to the formation of an Al-Cu oxide cover on the Cu NPs. The present results provide evidence for mixing of species from the host and Cu at the surface of the NPs, and it is shown how the degree of mixing depends on the laser fluence used to ablate the Al(2)O(3) host target.     

ZTM15(2Y)/Al2O3材料低温时效的研究

在AZTM15（2Y）中加入Al2O3粒子,可以改善材料的微观结构,使ZTM15（2Y）材料的室温力学性能提高,尤其是材料的断裂韧性,由4.0MPalm1/2增至7.8MP.^1/2,其主要贡献源于微鲜明纹增韧,但由于Al2O3粒子的引入,增加了ZTM15（2Y)基体中微裂纹的密度,所以不能有效抑制TM15（2Y）材料低温时效处理力学性能下降现象,相反,将另速材料力学性能的退化。     

Hg(0) oxidative absorption by K(2)S(2)O(8) solution catalyzed by Ag(+) and Cu(2+)

The aqueous phase oxidation of gaseous elemental mercury (Hg(0)) by potassium persulfate (K(2)S(2)O(8), KPS) catalyzed by Ag(+) and Cu(2+) was investigated using a glass bubble column reactor. Concentrations of gaseous Hg(0) and aqueous Hg(2+) were measured by cold vapor generation atomic absorption spectrometry (CVAAS). The effects of several experimental parameters on the oxidation were studied; these include different types of catalysts, pHs and concentrations of potassium persulfate, temperatures, Hg(0) inlet concentrations and tertiary butanol (TBA). The results showed that the removal efficiency of Hg(0) increased with increasing concentration of potassium persulfate and catalysts Ag(+), Cu(2+) and Ag(+) provided better catalytic effect than Cu(2+). For example, in the presence of 5.0mmoll(-1) KPS, the mercury removal efficiency could reach 75.4 and 97.0% for an Ag(+) concentration of 0.1 and 0.3mmoll(-1), respectively, and 69.8 and 81.9% for 0.1 and 0.3mmoll(-1) Cu(2+). On the other hand, high temperature and the introduction of TBA negatively affect the oxidation. Furthermore, the removal efficiency of Hg(0) was much greater in neutral solution than in either acidic or alkaline solution. But the influence of pH was almost eliminated upon the addition of Ag(+) and Cu(2+), and high Hg(0) inlet concentration also has positive impact on the removal efficiency of Hg(0). The possible catalytic oxidation mechanism of gaseous mercury by KPS was also proposed.     

Cu/Al_2O_3复合薄膜的制备及其抗氧化性能

本文在纺织纤维基材表面采用二次溅射沉积法制备了Cu/Al_2O_3复合薄膜,利用扫描电镜(SEM)、X射线能谱仪(EDX)和矢量网络分析仪对室温环境下存放3600h的复合薄膜的表面形貌、元素含量以及屏蔽效能进行了测试,并与相同工艺条件下制备的纯Cu薄膜进行了对比分析。结果表明:与纯Cu薄膜结构的不稳定性相比,由于复合薄膜表层Al_2O_3薄膜的结构稳定性和致密性,Cu/Al_2O_3复合薄膜在保证高屏蔽性能的前提下,具有整体结构的稳定性,表现出了良好的抗氧化性能。     

Influence of persulfate ions on the removal of phenol in aqueous solution using electron beam irradiation

The removal of phenol (Co = 100 μM) during electron beam irradiation was studied in pure water and in the presence of HCO(3)(-) and Br(-) ions. It was found that the introduction of S(2)O(8)(2-) ions (1mM), by generating SO(4)(-) radicals increases the radiation yield of phenol removal. 90% removal of phenol was obtained with radiation doses 600 and 1200 Gy with and without S(2)O(8)(2-) ions respectively. This system induced smaller oxygen consumption with smaller concentration of catechol and hydroquinone found in the solution. HCO(3)(-) and Br(-) have an inhibiting effect in the presence as in the absence of S(2)O(8)(2-). In most cases, the introduction of S(2)O(8)(2-) ions in water radiolysis system can advantageously increase the yield of organic compounds removal by oxidation.     

固体超强酸SO42-/TiO2-Al2O3的制备及其催化合成冰片

采用溶胶-凝胶法和浸渍法制备了系列SO_4~(2-)/TiO_2-Al_2O_3固体超强酸催化剂,运用XRD、NH_3-TPD、FT-IR、PyFTIR、XPS、SEM等技术手段,研究了复合催化剂材料的结构与性质,初步探讨了固体超强酸SO_4~(2-)/TiO_2-Al_2O_3催化剂的构效关系,得到适宜的催化剂制备条件为:n(TiO_2)/n(Al_2O_3)=1∶2、硫酸浸渍浓度1mol/L、催化剂焙烧温度500℃。考察了物料物质的量比、催化剂用量、反应时间等对催化合成冰片的影响。结果表明,在物料物质的量比为1∶0.4,催化剂用量为α-蒎烯质量的7%,采用程序升温方式(65℃-1h,75℃-4h,90℃-1h)加热的条件下,固体超强酸SO_4~(2-)/TiO_2-Al_2O_3催化剂的催化活性最高,α-蒎烯的转化率高达100%,龙脑的收率高达59.74%,SO_4~(2-)/TiO_2-Al_2O_3固体超强酸催化剂在重复使用6次的条件下,α-蒎烯的转化率均不变,龙脑的收率下降2.99%,催化剂的重复使用性良好。     

Al_6Si_2O_(13)晶须和TiC颗粒复合强化多孔Al_2TiO_5基复合材料

以γ-AlOOH和TiO_2为原料,添加不同质量分数SiC晶须(SiCw),采用无压反应烧结法制备多孔(Al_6Si_2O_(13)+TiC)/Al_2TiO_5复合材料,分析了SiCw质量分数对(Al_6Si_2O_(13)+TiC)/Al_2TiO_5复合材料孔隙率和抗压强度的影响,讨论了SiCw的强化机制。结果表明:不添加SiCw时,产物主要为Al_2TiO_5和少量Al_2O_3,还有少量未反应的TiO_2;加入SiCw之后,还形成了Al_6Si_2O_(13)和TiC相,TiC和Al_6Si_2O_(13)分别以规则颗粒状和晶须形态存在于Al_2TiO_5基体中。TiC颗粒与Al_6Si_2O_(13)晶须通过细化显微组织、裂纹偏转和晶须桥连机制,起到协同强化作用。SiCw的添加使孔隙率和抗压强度同时大幅度提高,随着SiCw质量分数的增加,(Al_6Si_2O_(13)+TiC)/Al_2TiO_5复合材料孔隙率降低,抗压强度提高的速率减小,当SiCw的质量分数为7.2%时,抗压强度最高,达到301.81 MPa。