期刊文献+
共找到1,190篇文章
< 1 2 60 >
每页显示 20 50 100
Enhancing the stability of Ni Fe-layered double hydroxide nanosheet array for alkaline seawater oxidation by Ce doping 被引量:1
1
作者 Yongchao Yao Shengjun Sun +14 位作者 Hui Zhang Zixiao Li Chaoxin Yang Zhengwei Cai Xun He Kai Dong Yonglan Luo Yan Wang Yuchun Ren Qian Liu Dongdong Zheng Weihua Zhuang Bo Tang Xuping Sun Wenchuang(Walter)Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期306-312,共7页
Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability cau... Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution. 展开更多
关键词 Ce doping NiFe layered double hydroxide Seawater oxidation Electrocatalysis Cl^(-) repulsion
下载PDF
Complete stabilization of severely As-contaminated soil by a simple H2O2 pre-oxidation method combined with non-toxic TMT-15 and FeCl3·6H2O 被引量:2
2
作者 Chang-sheng Yue Ben Peng +3 位作者 Wei Tian Guang-hua Lu Gui-bo Qiu Mei Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第9期1105-1112,共8页
The stabilization of severely As-polluted soil has been a challenge, especially for the extremely toxic As(Ⅲ) contaminants. In this study, soil with a high As concentration(26084 mg/kg) was availably stabilized by a ... The stabilization of severely As-polluted soil has been a challenge, especially for the extremely toxic As(Ⅲ) contaminants. In this study, soil with a high As concentration(26084 mg/kg) was availably stabilized by a H2O2 pre-oxidation assisted TMT-15(Na3S3C3N3 solution with a mass fraction of 15%) and FeCl3·6 H2O stabilization method. The results showed that the combination of the two stabilizers(i.e., TMT-15 and FeCl3·6 H2O) presented a better stabilization behavior than either stabilizer used individually. The use of the H2O2 pre-oxidation assisted TMT-15 and FeCl3·6 H2O stabilization approach not only converted the As(Ⅲ) to As(Ⅴ) but also reduced the toxic leaching concentration of As to 1.61 mg/L, which is a safe level, when the additions of TMT-15 and FeCl3·6 H2O were 2 mL and 0.20 g, respectively. Thus, using only a simple H2O2 pre-oxidation to combine clean stabilization with non-toxic stabilizers TMT-15 and FeCl3·6 H2O could render the severely As-contaminated soil safe for disposal in a landfill. 展开更多
关键词 severely As-contaminated soil NON-TOXIC STABILIZERS combining STABILIZATION pre-oxidation
下载PDF
Effect of pre-oxidation on strength and thermal shock behavior of ZrB_2-SiC-graphite ceramic composites 被引量:1
3
作者 刘洋 梁军 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第1期12-16,共5页
A novelty technique,namely,pre-oxidation,has been proposed to improve the strength and thermal shock behavior of ZrB2-SiC-graphite ceramic composites,which is a promising candidate for ultra-high temperature ceramics ... A novelty technique,namely,pre-oxidation,has been proposed to improve the strength and thermal shock behavior of ZrB2-SiC-graphite ceramic composites,which is a promising candidate for ultra-high temperature ceramics (UHTCs) in aerospace engineering. The composite is pre-oxidized at temperatures of 900 ℃ and 1100 ℃ for 1 h and 3 h in air. A theoretical model considering surface heat transfer has been given and analyzed. A water-quenching technique is adopted at different temperatures from 300 ℃ to 600 ℃ in order to investigate the thermal shock behavior of pre-oxidized composites. The critical thermal shock temperature improves more than 40% after pre-oxidizing at 1100 ℃ for 3 h. However,the composites strength is not improved as a result of the insensitivity to surface defects. 展开更多
关键词 UHTCs thermal properties thermal shock pre-oxidation STRENGTH
下载PDF
Effects of Pre-oxidation Conditions on Adsorption Performance of Activated Carbon Fibers 被引量:2
4
作者 蔡玉琳 徐山青 丁辛 《Journal of Donghua University(English Edition)》 EI CAS 2012年第3期249-253,共5页
In order to investigate the effects of pre-oxidation conditions on adsorption performance of activated carbon fibers ( ACFs ), electrospun polyacrylonitrile ( PAN ) fiber webs were adopted as precursors for prepar... In order to investigate the effects of pre-oxidation conditions on adsorption performance of activated carbon fibers ( ACFs ), electrospun polyacrylonitrile ( PAN ) fiber webs were adopted as precursors for preparing ACFs. Firstly, the webs were stabilized under different pre-oxidation conditions; secondly, the pre-oxidative fibers were chemically activated by high temperature treatment in nitrogen. Pre-oxidation temperature, heating rate, and treatment time are the main factors on affecting the adsorption performance of the ACFs. Scanning electron microscope ( SEM), differential scanning calorimeter (DSC), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the structure and property of the pre-oxldatlve fibers, and the dynamic benzene adsorption capacity of benzene of ACFs was measured. The results indicate that the moderate pre-oxidation condition is necessary to prepare the ACFs with better adsorption capacity, and the optimal oxidation conditions are to increase from room temperature to 230 ~C with a heating rate of 0.75 ~C ~ min -1 held at the peak temperature for 30min. 展开更多
关键词 polyaerylonitrile PAN ELECTROSPINNING pre-oxidation extent of reaction activated carbon fibers( ACFs benzene adsorption
下载PDF
Propene and CO oxidation on Pt/Ce-Zr-SO_4^(2-) diesel oxidation catalysts:Effect of sulfate on activity and stability 被引量:9
5
作者 顾蕾 陈晓 +3 位作者 周瑛 朱秋莲 黄海凤 卢晗锋 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第3期607-616,共10页
Platinum/cerium-zirconium-sulfate(Pt/Ce-Zr-SO_4^(2-)) catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate(SO_4^(2-))addition improv... Platinum/cerium-zirconium-sulfate(Pt/Ce-Zr-SO_4^(2-)) catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate(SO_4^(2-))addition improved the catalytic activity significantly.When using Pt/Ce-Zr-SO_4^(2-) with 10 wt%SO_4^(2-),the temperature for 90%conversion of propene and CO decreased by 75℃ compared with Pt/Ce-Zr.The conversion exceeded 95%at 240℃ even after 0.02%sulfur dioxide poisoning for 20 h.Temperature-programmed desorption of CO and X-ray photoelectron spectroscopy analyses revealed an improvement in Pt dispersion onto the Ce-Zr-SO_4^(2-) support,and the increased number of Pt particles built up more Pt^(-)-(SO_4^(2-))^(-) couples,which resulted in excellent activity.The increased total acidity and new Bronsted acid sites on the surface provided the Pt/Ce-Zr-SO_4^(2-) with good sulfur resistance. 展开更多
关键词 Diesel oxidation catalyst Pt/Ce-Zr-SO_4^(2- catalyst Sulfur resistance Catalytic oxidation
下载PDF
The Application of KMnO_4 Pre-oxidation in Emergency Treatment of High-algae Source Water
6
作者 Wang Zhanjin Pan Zhangbin +1 位作者 Jia Ruibao Sun Shaohua 《Meteorological and Environmental Research》 CAS 2014年第11期49-51,共3页
Mobile emergency pilot water plant was used to carry out pilot study of KMnO4 pre-oxidation enhanced coagulation treating high-algae source water. Research showed that the optimal dosages of coagulant and KMnO4 in the... Mobile emergency pilot water plant was used to carry out pilot study of KMnO4 pre-oxidation enhanced coagulation treating high-algae source water. Research showed that the optimal dosages of coagulant and KMnO4 in the process were 6 and 0. 4- 0. 6 mg / L respectively. Under the dosage,removal rate of water turbidity after precipitation rose by 11% than simple coagulation,and removal rate of algae rose by 15%. Removal rates of total amount of odor and GSM by the process were respectively 73% and 59%. The removal rate of total amount of algae by KMnO4 preoxidation was 40%,and removal effect of THM precursors was obvious. 展开更多
关键词 KMnO_4 pre-oxidation High-algae source water Enhanced coagulation THM precursors China
下载PDF
Methane Oxidation to Synthesis Gas Using Lattice Oxygen of La_(1-x)Sr_xMO_(3-λ)(M =Fe,Mn) Perovskite Oxides Instead of Molecular Oxygen 被引量:10
7
作者 LiRanjia YuChangchun ZhuGuangrong ShenShikong 《Petroleum Science》 SCIE CAS CSCD 2005年第1期19-23,共5页
In this paper, the partial oxidation of methane to synthesis gas using lattice oxygen of La1- SrxMO3-λ (M=Fe, x ... In this paper, the partial oxidation of methane to synthesis gas using lattice oxygen of La1- SrxMO3-λ (M=Fe, x Mn) perovskite oxides instead of molecular oxygen was investigated. The redox circulation between 11% O2/Ar flow and 11% CH4/He flow at 900℃ shows that methane can be oxidized to CO and H2 with a selectivity of over 90.7% using the lattice oxygen of La1- SrxFeO3-λ (x≤0.2) perovskite oxides in an appropriate reaction condition, while the lost lattice x oxygen can be supplemented by air re-oxidation. It is viable for the lattice oxygen of La1- SrxFeO3-λ (x≤0.2) perovskite x oxides instead of molecular oxygen to react with methane to synthesis gas in the redox mode. 展开更多
关键词 Partial oxidation METHANE synthesis gas lattice oxygen La1- xSrxFeO3-λperovskite oxides
下载PDF
Non-isothermal oxidation of coal with Ce(NO3)3 and Cu(NO3)2 additives 被引量:3
8
作者 Kirill Borisovich Larionov Alexander Alexandrovich Gromov 《International Journal of Coal Science & Technology》 EI 2019年第1期37-50,共14页
Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO3)2, 5 wt% of Ce(NO3)3 and {2.5 wt% Cu(NO3)2 + 2.5 wt% Ce(NO3)3} additives was studied. The introduction of additives was carried out by an incipient wet impre... Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO3)2, 5 wt% of Ce(NO3)3 and {2.5 wt% Cu(NO3)2 + 2.5 wt% Ce(NO3)3} additives was studied. The introduction of additives was carried out by an incipient wet impregnation method to ensure uniform distribution of cerium and copper nitrates within the structure of coal powdery samples (according to SEM and EDX mapping). The samples reactivity was studied in an isothermal oxidation regime at 200 °C (1 h) and by DSC/TGA at 2.5 °C/min heating rate. The additives implementation was found to reduce significantly the oxidation onset temperature (△Ti = 20-55 °C), the samples oxidation delay time (△ti= 2-22 min) and overall duration of the oxidation process (△tc = 8-16 min). The additives efficiency could be graded in accordance with the activation on the coal oxidation in the following row: Cu(NO3)2 >{Cu(NO3)2 + Ce(NO3)3}> Ce(NO3)3. According to the mass spectroscopy, the obtained row of activation correlates well with the initial temperature of the studied nitrate's decomposition (from 190 to 223 °C). A presence of nitrates was found to change significantly the trend of heat release taking place during the oxidation of coal samples (according to DSC/TGA data). The influence of coal morphology and volatiles concern in initial sample on the parameters of the oxidation process was studied as well. Activation energy (Ea) of the coal oxidation was calculated using Coats-Redfern method. Maximum decrease in Ea from 69 to 58 kJ/mol was observed for the samples with Cu(NO3)2. Graphical abstract. 展开更多
关键词 Coal oxidation REACTIVITY DSC/DTG/TGA/MS Copper NITRATE - CERIUM NITRATE
下载PDF
Ca and Sr co-doping induced oxygen vacancies in 3DOM La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts for boosting low-temperature oxidative coupling of methane
9
作者 Tongtong Wu Yuechang Wei +5 位作者 Jing Xiong Yitao Yang Zhenpeng Wang Dawei Han Zhen Zhao Jian Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期331-344,共14页
It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(... It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(A_(2)B_(2)O_(7)-type)catalysts with disordered defective cubic fluorite phased structure were successfully prepared by a colloidal crystal template method.3DOM structure promotes the accessibility of the gaseous reactants(O2and CH4)to the active sites.The co-doping of Ca and Sr ions in La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts improved the formation of oxygen vacancies,thereby leading to increased density of surface-active oxygen species(O_(2)^(-))for the activation of CH4and the formation of C2products(C2H6and C2H4).3DOM La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts exhibit high catalytic activity for OCM at low temperature.3DOM La1.7Sr0.3Ce1.7Ca0.3O7-δcatalyst with the highest density of O_(2)^(-)species exhibited the highest catalytic activity for low-temperature OCM,i.e.,its CH4conversion,selectivity and yield of C2products at 650℃are 32.2%,66.1%and 21.3%,respectively.The mechanism was proposed that the increase in surface oxygen vacancies induced by the co-doping of Ca and Sr ions boosts the key step of C-H bond breaking and C-C bond coupling in catalyzing low-temperature OCM.It is meaningful for the development of the low-temperature and high-efficient catalysts for OCM reaction in practical application. 展开更多
关键词 3DOM catalysts Ca ions Sr ions Low-temperature oxidative couplingof methane Oxygen vacancies O_(2)^(-) species
下载PDF
Cr-poisoning under open-circuit condition in LaNi_(0.6)Fe_(0.4)O_(3-δ)-based nano composite cathodes for solid oxide fuel cells prepared by infiltration process 被引量:1
10
作者 Yeong-Ju CHOE Jeong-Uk SEO +2 位作者 Kyoung-Jin LEE Min-Jin LEE Hae-Jin HWANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第5期1367-1372,共6页
LaNi(0.6)Fe(0.4)O(3-δ) (LNF) powders were synthesized by the glycine-nitrate process and LNF-gadolinium-doped ceria (GDC) nanocomposite cathodes for solid oxide fuel cells (SOFCs) were fabricated by infil... LaNi(0.6)Fe(0.4)O(3-δ) (LNF) powders were synthesized by the glycine-nitrate process and LNF-gadolinium-doped ceria (GDC) nanocomposite cathodes for solid oxide fuel cells (SOFCs) were fabricated by infiltration from LNF porous backbones. Electrochemical properties and Cr-poisoning behavior of LNF-GDC cathodes were studied. Single phase perovskite LNF could be obtained at the glycine to nitrate molar ratio of 1:1. The polarization resistance of the LNF-GDC nanocomposite cathode was significantly decreased in comparison with the LNF. This phenomenon was associated with enhanced catalytic activity and enlarged triple-phase boundary (TPB) length by GDC nano particles. In addition, the nanocomposite cathode showed good Cr tolerance under open circuit condition. The LNF-GDC nanocomposite cathodes were expected for use as a potential cathode in intermediate- temperature solid oxide fuel cells (IT-SOFC). 展开更多
关键词 Cr-poisoning PEROVSKITE INFILTRATION solid oxide fuel cell LaNi0.6Fe0.4O3-δ
下载PDF
Effect of ZnO on Oxidation Resistance of Low Carbon MgO-C Refractories
11
作者 XIE Zhaohui CHEN Liugang +1 位作者 ZHAI Pengtao ZHANG Yang 《China's Refractories》 CAS 2014年第2期7-11,共5页
Al-containing low carbon MgO - C refractories were prepared using 70% (in mass, the same hereinafter) fused magnesia ( ≤3 mm), 24% fused magnesia powder ( 〈0. 074 mm) , 3% flake graphite, 3% Al powder and 4% p... Al-containing low carbon MgO - C refractories were prepared using 70% (in mass, the same hereinafter) fused magnesia ( ≤3 mm), 24% fused magnesia powder ( 〈0. 074 mm) , 3% flake graphite, 3% Al powder and 4% phenolic resin (extra-added) as the basic formulation. Influence of ZnO addhion on oxidation resistance of the materials was investigated by adding 1% ZnO to substitute fused magnesia powder. The relationship between in-situ formed spinel and ZnO in the matrix was discussed by comparing apparent porosity, cold crushing strength, and phase evolution of the materials matrix. The oxidation resistances of the two materials were compared by observing the formed dense MgO layer between the decarburized layer and the original layer. The result shows that adding ZnO in MgO - C refractories accelerates the in-situ formation of ZnAl204 spinel and the formation of dense MgO layer, thus improves the oxidation resistance of the low carbon MgO - C refractories. 展开更多
关键词 zinc oxide magnesia - carbon refracto-ries in-situ spinel oxidation resistance
下载PDF
Coherent-Synchronized Oxidation of Pyridine with Nitrous Oxide to 2,2- and 2,3-Dipyridil
12
作者 Nagieva Inara Ali-zadeh Nahmad Nagiev Tofik 《Journal of Chemistry and Chemical Engineering》 2016年第2期99-102,共4页
Synthesis of pyridine bases by way of relatively simple transformations with use of cheaper and available raw, is an actual problem. In this aspect the method in which the reactions of hydro-carbons oxidation are indu... Synthesis of pyridine bases by way of relatively simple transformations with use of cheaper and available raw, is an actual problem. In this aspect the method in which the reactions of hydro-carbons oxidation are induced by nitrous oxide, is of scientific and practical interest. In the present work, the authors report the results of the experiments coherent-synchronized oxidation of pyridine with nitrous oxide to 2,2- and 2,3-dipyridyle. 展开更多
关键词 Coherent-synchronized nitrous oxide oxidation PYRIDINE 2 2- and 2 3-dipyridyle.
下载PDF
Partial Oxidation of Methane to Synthesis Gas over Hexaaluminates LaMAl_(11)O_(19-δ) catalysts
13
作者 Zhanlin Xu Lina Zhao Fang Pang Liang Wang Chunyan Niu 《Journal of Natural Gas Chemistry》 CAS CSCD 2007年第1期60-63,共4页
A series of M-substituted hexaaluminates LaMAl11O19-δ (M=Fe, Co, Ni, Mn, and Cu) were prepared and characterized by XRD, XPS, TPR and TGA techniques, respectively. They exhibited different reducibility and catalyti... A series of M-substituted hexaaluminates LaMAl11O19-δ (M=Fe, Co, Ni, Mn, and Cu) were prepared and characterized by XRD, XPS, TPR and TGA techniques, respectively. They exhibited different reducibility and catalytic activity for partial oxidation of methane (POM) to synthesis gas. Among the LaMAl11019-δ samples, LaNiAl11O19-δ showed the best catalytic activity for the topic reaction and selectivity for synthesis gas at 780 ℃ for 2 h. The conversion of CH4 was over 99.2%, and the product selectivity for both CO and H2 was above 90.3%. 展开更多
关键词 partial oxidation CH4 synthesis gas HEXAALUMINATES LaMAl11 O19-δ Fe Co NI MN Cu
下载PDF
Analysis and Characterization of Orientation Structure of Pre-oxidized PAN Fibers in High Magnetic Fields
14
作者 任小孟 王源升 +1 位作者 HE Te XIA Zhengcai 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第2期224-228,共5页
PAN fibers pre-oxidized at 240℃, 260℃, 280℃, 300℃ were treated in 8 T, 12 T, 16 T high magnetic fields, respectively. The experimental result implied that there were two kinds of magnetic units cyan and carbon-nit... PAN fibers pre-oxidized at 240℃, 260℃, 280℃, 300℃ were treated in 8 T, 12 T, 16 T high magnetic fields, respectively. The experimental result implied that there were two kinds of magnetic units cyan and carbon-nitrogen heterocycle in pre-oxidized PAN fibers, and the movement of magnetic units resulted in changes of orientation structure of pre-oxidized PAN fibers in high magnetic fields. Overall orientation increased with increase of magnetic field intensity and extension of processing time, whereas change of crystalline orientation depended on magnetic field intensity and content of carbon-nitrogen heterocycle due to the competition of two magnetic units. Furthermore, magnetic fields induced the conversion from amorphous region to crystal region and improved crystalline orooerties of ore-oxidized PAN fibers. 展开更多
关键词 pre-oxidized PAN magnetic field ORIENTATION
下载PDF
Oxidation of Al_2O_3-30%TiCN-0.2%Y_2O_3 Composite
15
作者 李喜坤 邱关明 +3 位作者 修稚萌 孙旭东 严长浩 代少俊 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第3期276-279,共4页
The oxidation behavior of Al2O3-30%TiCN-0.2%Y2O3 composite and its effect on high temperature bending strength was studied. The result indicates that the mass gain during static oxidation of the material under normal ... The oxidation behavior of Al2O3-30%TiCN-0.2%Y2O3 composite and its effect on high temperature bending strength was studied. The result indicates that the mass gain during static oxidation of the material under normal atmosphere follows the parabolic law. Oxide increases with increasing temperature and prolonging time. It has good oxidation resistance. The product of oxidation of the material is TiO2. Therefore, the volume of the material expands. The oxide film is destroyed because residual stress inside the oxide film is released. Proper oxidation is beneficial to the improvement of bending strength of Al2O3-30%TiCN-0.2%Y2O3 composite. The strength increase is up to 4.5%. 展开更多
关键词 COMPOSITE Al2O3-30%TiCN-0.2%Y2O3 oxidation behavior bend strength parabolic law residual stress rare earths
下载PDF
Improvement in electrical properties of high-κ film on Ge substrate by an improved stress relieved pre-oxide method
16
作者 樊继斌 丁晓甫 +3 位作者 刘红侠 谢鹏飞 张袁涛 廖清良 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第2期468-471,共4页
High-κ /Ge gate stack has recently attracted a great deal of attention as a potential candidate to replace planar silicon transistors for sub-22 generation. However, the desorption and volatilization of GeO hamper th... High-κ /Ge gate stack has recently attracted a great deal of attention as a potential candidate to replace planar silicon transistors for sub-22 generation. However, the desorption and volatilization of GeO hamper the development of Ge-based devices. To cope with this challenge, various techniques have been proposed to improve the high-κ /Ge interface. However,these techniques have not been developed perfectly yet to control the interface. Therefore, in this paper, we propose an improved stress relieved pre-oxide(SRPO) method to improve the thermodynamic stability of the high-κ /Ge interface. The x-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM) results indicate that the GeO volatilization of the high-κ /Ge gate stack is efficiently suppressed after 500℃ annealing, and the electrical characteristics are greatly improved. 展开更多
关键词 high-K film GeO volatilization stress relieved pre-oxide ANNEALING
下载PDF
Correlation of maternal - placental circulation ultrasound parameters with placental hypoxia and oxidative stress in patients with preeclampsia
17
作者 Min Zhao 《Journal of Hainan Medical University》 2017年第20期69-72,共4页
Objective: To study the correlation of maternal - placental circulation ultrasound parameters with placental hypoxia and oxidative stress in patients with preeclampsia. Methods: Patients with preeclampsia who gave bir... Objective: To study the correlation of maternal - placental circulation ultrasound parameters with placental hypoxia and oxidative stress in patients with preeclampsia. Methods: Patients with preeclampsia who gave birth in Shandong jiaotong hospital between March 2015 and February 2017 were select as the PE group of the study, and the healthy pregnant women who gave birth in the hospital during the same period were selected as the control group of the study. Color Doppler ultrasonography was done in the 23-26 weeks of pregnancy to determine the uterine spiral artery PI, RI and S/D levels;after delivery, the placenta was collected to determine the expression of hypoxia-induced apoptosis indexes, cell invasion molecules and oxidative stress molecules. Results: Uterine spiral artery PI, RI and S/D levels of PE group were significantly higher than those of control group;TXNIP, NLRP3, ASC, Caspase-1, Nrf-2, HO-1 and NQO-1 mRNA expression in placenta tissue of PE group were significantly higher than those of control group and positively correlated with uterine spiral artery PI, RI and S/D levels while CatL, CatB, uPA and LAMA4 mRNA expression were significantly lower than those of control group and negatively correlated with uterine spiral artery PI, RI and S/D levels. Conclusion: The increase of maternal - placental circulation blood resistance in patients with preeclampsia will result in the placental hypoxia, and aggravate the apoptosis and oxidative stress. 展开更多
关键词 preECLAMPSIA MATERNAL - PLACENTAL CIRCULATION Apoptosis INVASION oxidative stress
下载PDF
Coupling of on-Line Pre-Column Oxidative Cleavage and Solid-Phase Enrichment with Liquid Chromatography Using an Eco-Friendly Analytical Procedure to Determine Low Levels of Methotrexate
18
作者 Samy Emara Walaa Zarad +1 位作者 Maha Kamal Ramzia EL-Bagary 《Journal of Analytical Sciences, Methods and Instrumentation》 2012年第4期194-202,共9页
A simple, sensitive and precise green high-performance liquid chromatographic method including on-line pre-column oxidation combined by column switching with a short Hypersil ODS analytical column (100 mm × 4.0 m... A simple, sensitive and precise green high-performance liquid chromatographic method including on-line pre-column oxidation combined by column switching with a short Hypersil ODS analytical column (100 mm × 4.0 mm i.d.) for enrichment and separation was developed and validated to determine low levels of methotrexate (MTX). The method was based on oxidative cleavage of MTX into highly fluorescence products, 2,4-diaminopteridine-6-carboxaldehyde and the corresponding 2,4-diaminopteridine-6-carboxylic acid, during the flow of phosphate buffer (0.04 M, pH 3.4) containing the analyte through the packed reactor of cerium (IV) trihydroxyhydroperoxide (CTH) at a flow-rate of 0.2 mL/min and 40℃. The fluorescent products were enriched on the head of ODS analytical column for the final separation. The separation was performed at room temperature using an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 10:90 (v/v). The eluent was monitored at emission and excitation wavelengths of 463 and 367 nm, respectively. The method was successfully applied, without any interference from the excipients, for the determination of drug in tablets and vials with a detection limit of 0.06 ng/mL from 500 ?L of sample MTX. 展开更多
关键词 Cerium (IV) Trihydroxyhydroperoxide HPLC METHOTREXATE ODS ANALYTICAL Column ON-LINE pre-Column oxidative CLEAVAGE
下载PDF
Leaching of low grade zinc oxide ores in Ida^(2-)-H_2O system 被引量:6
19
作者 窦爱春 杨天足 +2 位作者 杨际幸 吴江华 王安 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第11期2548-2553,共6页
Ida2--H2O system(iminodiacetate aqueous solution) was used to leach a low grade zinc oxide ore for Zn extraction.The effects of leaching time,liquid-solid ratio(L/S),total concentration of Ida2-([Ida2-]T),leachi... Ida2--H2O system(iminodiacetate aqueous solution) was used to leach a low grade zinc oxide ore for Zn extraction.The effects of leaching time,liquid-solid ratio(L/S),total concentration of Ida2-([Ida2-]T),leaching temperature and pH on Zn leaching recovery and the dissolution of impurities such as Ca,Mg,Cu,Ni,Fe,Pb and Cd were investigated.Results show that Ca,Mg and Fe in ores were hardly dissolved in alkalescent iminodiacetate aqueous solution,while valuable metals such as Cu,Ni,Pb and Cd were partly dissolved into leaching liquor with Zn.The recovery of Zn reaches 76.6% when the ores were leached for 4 h at 70 ℃ by 0.9 mol/L iminodiacetate aqueous solution with pH of 8 and L/S of 5:1. 展开更多
关键词 Ida2- zinc oxide ore LEACHING
下载PDF
HBV PreS2+S/IFN-α融合基因真核表达载体的构建及其表达 被引量:3
20
作者 陈红梅 白雪帆 +3 位作者 潘蕾 李光玉 韦三华 黄长形 《中国病毒学》 CSCD 2002年第4期312-314,共3页
构建含HBVPrdS2 +S和IFN α融合基因的真核表达载体pcDNA3.1.S2S/IFN α并在真核细胞中进行表达。应用重叠延伸剪切技术 (splicingbyoverlappingextension ,简称SOE)经两次PCR获得嵌合基因片段S2S/IFN α ,回收后直接克隆到 pcDNA3.1V5 ... 构建含HBVPrdS2 +S和IFN α融合基因的真核表达载体pcDNA3.1.S2S/IFN α并在真核细胞中进行表达。应用重叠延伸剪切技术 (splicingbyoverlappingextension ,简称SOE)经两次PCR获得嵌合基因片段S2S/IFN α ,回收后直接克隆到 pcDNA3.1V5 /HisTOPOTA克隆载体 ,得到真核重组载体pcDNA3.1.S2S/IFN α。然后用脂质体法转染VeroE6细胞。对重组载体进行了限制性酶切及PCR鉴定 ,证明连接正确 ;经间接免疫荧光检测证实该重组载体能在真核细胞中表达插入的外源性基因编码的融合蛋白。真核表达载体pcDNA3.1.S2S/IFN α的成功构建及在VeroE6细胞中的有效表达 。 展开更多
关键词 HBV preS2+S/INF-α融合基因 真核表达载体 乙型肝炎病毒 Α-干扰素 基因表达
下载PDF
上一页 1 2 60 下一页 到第
使用帮助 返回顶部