期刊文献+
共找到426,621篇文章
< 1 2 250 >
每页显示 20 50 100
Crystal plane induced in-situ electrochemical activation of manganese-based cathode enable long-term aqueous zinc-ion batteries 被引量:3
1
作者 Yuxin Gao Jiang Zhou +6 位作者 Liping Qin Zhenming Xu Zhexuan Liu Liangbing Wang Xinxin Cao Guozhao Fang Shuquan Liang 《Green Energy & Environment》 SCIE EI CAS CSCD 2023年第5期1429-1436,共8页
Rapid capacity decay and sluggish reaction kinetics are major barriers hindering the applications of manganese-based cathode materials for aqueous zinc-ion batteries.Herein,the effects of crystal plane on the in-situ ... Rapid capacity decay and sluggish reaction kinetics are major barriers hindering the applications of manganese-based cathode materials for aqueous zinc-ion batteries.Herein,the effects of crystal plane on the in-situ transformation behavior and electrochemical performance of manganese-based cathode is discussed.A comprehensive discussion manifests that the exposed(100)crystal plane is beneficial to the phase transformation from tunnel-structured MnO_(2) to layer-structured ZnMn_(3)O_(7)·3H_(2)O,which plays a critical role for the high reactivity,high capacity,fast diffusion kinetics and long cycling stability.Additionally,a two-stage zinc storage mechanism can be demonstrated,involving continuous activation reaction and phase transition reaction.As expected,it exhibits a high capacity of 275 mAh g^(-1)at 100 mA g^(-1),a superior durability over 1000 cycles and good rate capability.This study may open new windows toward developing advanced cathodes for ZIBs,and facilitate the applications of ZIBs in large-scale energy storage system. 展开更多
关键词 Crystal plane Electrochemical activation Phase transition reaction Cycling stability Zinc-ion batteries
下载PDF
Preparation and Characterization of Activated Carbons from Asparagus Palm (Laccosperma robustum) Bark by Chemical Activation with H3PO4 and KOH
2
作者 Phil Lewis Mpampoungou Langama Jean Jacques Anguile +4 位作者 Crislain Bissielou Adam Bouraïma Albert Novy Messi Me Ndong Daouda Kouotou Joseph Ketcha Mbadcam 《American Journal of Analytical Chemistry》 CAS 2023年第2期55-71,共17页
The present work deals with the preparation and characterization of activated carbons from the bark of the asparagus palm (Laccosperma robustum) by chemical activation with phosphoric acid and potassium hydroxide. The... The present work deals with the preparation and characterization of activated carbons from the bark of the asparagus palm (Laccosperma robustum) by chemical activation with phosphoric acid and potassium hydroxide. The process was optimized on the basis of the analysis of the iodine number, methylene blue number and activated carbons yield as a function of the preparation parameters (concentration of the activating agents and the pyrolysis temperature). It emerges that the pyrolysis temperature and the concentration of activating agents influence the activated carbons preparation process. Their values were 500°C and 20% respectively for activated carbon with H<sub>3</sub>PO<sub>4</sub> (ACP) and 700°C and 1.5% for activated carbon with KOH (ACK). The iodine numbers obtained were 850.26 mg/g for ACP and 865.49 mg/g for ACK. The methylene blue numbers obtained were 149.35 mg/g for ACP and 149.25 mg/g for ACK. The activated carbons yields obtained were 25% for ACP and 5.9% for ACK. The activated carbons prepared under optimal conditions have shown the pH of zero-point charge (pHzpc) of 4.4 and 7.0 for ACP for ACK respectively. The determination of the surface functions revealed that ACP had a strong acidic character while ACK had neutral character. The Fourier transformed infrared spectroscopy also showed the presence of different functional groups on the surface of the precursor and activated carbons. 展开更多
关键词 Activated Carbons Asparagus Palm Bark chemical activation Phosphoric Acid Potassium Hydroxide
下载PDF
A Study of Heavy-Fermion Superconductors via BCS Equations Incorporating Chemical Potential 被引量:2
3
作者 G. P. Malik 《Journal of Modern Physics》 2015年第9期1233-1242,共10页
Heavy-fermion superconductors (HFSCs) are regarded as outside the purview of BCS theory because it is usually constrained by the inequality , where EF, μ, kB, and θD are, respectively, the Fermi energy, chemical pot... Heavy-fermion superconductors (HFSCs) are regarded as outside the purview of BCS theory because it is usually constrained by the inequality , where EF, μ, kB, and θD are, respectively, the Fermi energy, chemical potential, Boltzmann constant, and the Debye temperature. We show that this restriction can be removed by incorporating μ into the equations for Tc and the gap Δ0 at T = 0. Further, when μ kBθD, we curtail the limits of the equations for Tc and Δ0 to avoid complex-valued solutions. The resulting equations are applied to a prominent member of the HFSC family, i.e., CeCoIn5, by appealing to ideas due to Born and Karmann, Suhl et al., and Bianconi et al. Since the equations now contain an additional variable μ, we find that 1) the Tc of the SC can be accounted for by a multitude of values of the (μ, λ) pair, λ being the interaction parameter;2) the λ vs. μ plot has a dome-like structure when μ kBθD;3) the (μ, λ) values obtained in 2) lead to reasonable results for the range of each of the following variables: Δ0, s, and n, where s is the ratio of the mass of a conduction electron and the free electron mass and n is the number density of charge carriers in the SC. 展开更多
关键词 Range of Application of the BCS THEORY Incorporation of chemical Potential into EQUATIONS for Tc and Δ0 Extended BCS THEORY HEAVY-FERMION Superconductors Ratio of the MASS of a Conduction ELECTRON and the Free ELECTRON MASS Density of Charge Carriers
下载PDF
Adjusting oxygen vacancies in perovskite LaCoO_(3)by electrochemical activation to enhance the hydrogen evolution reaction activity in alkaline condition 被引量:1
4
作者 Chengrong Wu Yan Sun +4 位作者 Xiaojian Wen Jia-Ye Zhang Liang Qiao Jun Cheng Kelvin H.L.Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期226-232,I0006,共8页
Developing highly-active,earth-abundant non-precious-metal catalysts for hydrogen evolution reaction(HER)in alkaline solution would be beneficial to sustainable energy storage.Perovskite oxides are generally regarded ... Developing highly-active,earth-abundant non-precious-metal catalysts for hydrogen evolution reaction(HER)in alkaline solution would be beneficial to sustainable energy storage.Perovskite oxides are generally regarded as low-active HER catalysts,due to their inapposite hydrogen adsorption and water dissociation.Here,we report a detailed study on perovskite LaCoO_(3)epitaxial thin films as a model catalyst to significantly enhance the HER performance via an electrochemical activation process.As a result,the overpotential for the activation films to achieve a current density of 0.36 m A/cm^(2)is 238 m V,reduced by more than 200 m V in comparison with that of original samples.Structural characterization revealed the activation process dramatically increases the concentration of oxygen vacancies(Vo)on the surface of LaCoO_(3).We established the relationship between the electronic structure induced by Vo and the enhanced HER activity.Further theoretical calculations revealed that the Vo optimizes the hydrogen adsorption and dissociation of water on the surface of LaCoO_(3)thin films,thus improving the HER catalytic activity.This work may promote a deepened understanding of perovskite oxides for HER mechanism by Vo adjusting and a new avenue for designing highly active electrochemical catalysts in alkaline solution. 展开更多
关键词 Hydrogen evolution reaction Perovskite oxides activation process Oxygen vacancies
下载PDF
Phytochemical and anti-bacterial activity of epidermal glands extract of Christella parasitica (L.) H. Lev. 被引量:14
5
作者 Paul Raj K Irudayaraj V +1 位作者 Johnson M Patric Raja D 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2011年第1期8-11,共4页
Objective:To study the morphology,biochemistry and bioactivity of the epidermal glands of the glandular morphotype of Christella parasitica(C.parasitica)(L.) H.Lev.Methods: Morphological studies on epidermal glands we... Objective:To study the morphology,biochemistry and bioactivity of the epidermal glands of the glandular morphotype of Christella parasitica(C.parasitica)(L.) H.Lev.Methods: Morphological studies on epidermal glands were earned out by using light microscope and scanning electron microscope.To prepare the extract,the shade-dried fronds of glandular morphotype were soaked in acetone.For antibacterial studies paper disc method was followed by using various pathogenic bacteria.Results:Detailed micromorphological,phytochemical and bioactivity studies on a medicinal fern C.parasitica(L.) H.Lev.showed its inlraspecific variation in antibacterial activity.The presence or absence of the epidermal glands was the key factor for antibacterial activity in the morphovariants of this species.The epidermal glands were orange-coloured,stalked and elongated ones of about 84.2μm×45μm,and distributed on the undersurface of cosla,coslules and veins in croziers,young and mature leaves.Frequency of glands varied from 15/cm on costa in mature leaves to 140/cm on costules in croziers.The acetone extract of the glands showed antibacterial activities and also toxic effect against mosquito larvae and tadpoles of frog.Preliminary phytochemical analysis and HPLC studies of the gland extract showed the presence of various kinds of terpenoids,alkaloids,tannins,saponins and flavonoids in it.Conclusions:The present study shows that epidermal glands of the glandular morphotype of C. parasitica(L.) H.Lev.have several bioactive compounds and such rare moiphovariant should be conserved in nature.The next step is to isolate the pure compounds and to screen the bioactivity of individual compounds of the epidermal glands. 展开更多
关键词 EPIDERMAL GLANDS Christella parasitica Bioactivity PHYTOchemical ACTIVITY Anti-bacterial ACTIVITY Morphology Biochemistry Glandular MORPHOTYPE Light microscope Shade-dried frond Bioactive compound Morphovariant Preliminary PHYTOchemical analysis Gland EXTRACT Flavonoid
下载PDF
Immobilization of organophosphorus hydrolase enzyme by covalent attachment on modified cellulose microfibers using different chemical activation strategies:Characterization and stability studies 被引量:5
6
作者 Meisam Sharifi Seyed-Mortaza Robatjazi +1 位作者 Minoo Sadri Jafar Mohammadian Mosaabadi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第1期191-199,共9页
The plant cellulose powder was activated by two different methods using 1,4-butanediol diglycidyl ether(BTDE)and 1,1′-Carbonyldiimidazole(CDI) as the chemical coupling agents.Organophosphorus hydrolase(OPH) from Flav... The plant cellulose powder was activated by two different methods using 1,4-butanediol diglycidyl ether(BTDE)and 1,1′-Carbonyldiimidazole(CDI) as the chemical coupling agents.Organophosphorus hydrolase(OPH) from Flavobacterium ATCC 27551 was immobilized on any of activated support through covalent bonding.The optimal conditions of affecting parameters on enzyme immobilization in both methods were found, and it was demonstrated that the highest activity yields of immobilized OPH onto epoxy and CDI treated cellulose were 68.32%and 73.51%, respectively.The surface treatment of cellulose via covalent coupling with BTDE and CDI agents was proved by FTIR analysis.The kinetic constants of the free and immobilized enzymes were determined, and it was showed that both immobilization techniques moderately increased the Kmvalue of the free OPH.The improvements in storage and thermal stability were investigated and depicted that the half-life of immobilized OPH over the surface of epoxy modified cellulose had a better growth compared to the free and immobilized enzymes onto CDI treated support.Also, the pH stability of the immobilized preparations was enhanced relative to the free counterpart and revealed that all enzyme samples would have the same optimum pH value for stability at 9.0.Additionally, the immobilized OPH onto epoxy and CDI activated cellulose retained about 59% and 68% of their initial activity after ten turns of batch operation, respectively.The results demonstrated the high performance of OPH enzyme in immobilized state onto an inexpensive support with the potential of industrial applications. 展开更多
关键词 ORGANOPHOSPHORUS HYDROLASE CELLULOSE powder activation IMMOBILIZATION Stability
下载PDF
Effect of chemical activation process on adsorption of As(V) ion from aqueous solution by mechano-thermally synthesized zinc ferrite nanopowder 被引量:1
7
作者 Mohammad Sefidmooy Azar Shahram Raygan Saeed Sheibani 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第4期526-537,共12页
Nanostructured ZnFe2O4 was synthesized by the heat treatment of a mechanically activated mixture of ZnO/α-Fe2O3.X-ray diffraction(XRD)and differential thermal analysis(DTA)results demonstrated that,after 5 h of the m... Nanostructured ZnFe2O4 was synthesized by the heat treatment of a mechanically activated mixture of ZnO/α-Fe2O3.X-ray diffraction(XRD)and differential thermal analysis(DTA)results demonstrated that,after 5 h of the mechanical activation of the mixture,ZnFe2O4 was formed by heat treatment at 750°C for 2 h.To improve the characteristics of ZnFe2O4 for adsorption applications,the chemical activation process was performed.The 2 h chemical activation with 1 mol·L?1 HNO3 and co-precipitation of 52%?57%dissolved ZnFe2O4 led to an increase in the saturated magnetization from 2.0 to 7.5 emu·g?1 and in the specific surface area from 5 to 198 m2·g?1.In addition,the observed particle size reduction of chemically activated ZnFe2O4 in field emission scanning electron microscopy(FESEM)micrographs was in agreement with the specific surface area increase.These improvements in ZnFe2O4 characteristics considerably affected the adsorption performance of this adsorbent.Adsorption results revealed that mechano-thermally synthesized ZnFe2O4 had the maximum arsenic adsorption of 38%with the adsorption capacity of 0.995 mg·g?1 in a 130 mg·L?1 solution of As(V)after 30 min of agitation.However,chemically activated ZnFe2O4 showed the maximum arsenic adsorption of approximately 99%with the adsorption capacity of 21.460 mg·g?1 under the same conditions.These results showed that the weak adsorption performance of mechano-thermally synthesized ZnFe2O4 was improved by the chemical activation process. 展开更多
关键词 zinc FERRITE mechano-thermal chemical activation ADSORPTION arsenic(V)
下载PDF
Eye on the Sky: A UAP Research and Field Study off New York’s Long Island Coast
8
作者 John Joseph Tedesco Gerald Thomas Tedesco 《Open Journal of Applied Sciences》 2024年第8期2267-2295,共29页
A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a... A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors. 展开更多
关键词 Unidentified Anomalous Phenomenon (UAP) Forensic Techno-Signatures Office of the Director of National Intelligence (ODNI) Multispectral Electro-Optical (MEO) Ultraviolet A Radiation (UVA) Ultraviolet B Radiation (UVB) Ultraviolet C Radiation (UVC) Visible (VIS) Near-Infrared (NIR) Short-Wave Infrared (SWIR) Long-Wave Infrared (LWIR) Low-Frequency (LF) High-Frequency (HF) Radio-Frequency (RF) Alpha Beta Gamma Ultrasonic X-Band Active Radar Kinematics Aerodynamics Luminous Spheroids Robert Moses State Park (RMSP)
下载PDF
Enhanced performance in the direct electrocatalytic synthesis of ammonia from N2 and H2O by an in-situ electrochemical activation of CNT-supported iron oxide nanoparticles 被引量:3
9
作者 Shiming Chen Siglinda Perathoner +4 位作者 Claudio Ampelli Hua Wei Salvatore Abate Bingsen Zhang Gabriele Centi 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第10期22-32,共11页
The direct electrocatalytic synthesis of ammonia from N2 and H2O by using renewable energy sources and ambient pressure/temperature operations is a breakthrough technology,which can reduce by over 90%the greenhouse ga... The direct electrocatalytic synthesis of ammonia from N2 and H2O by using renewable energy sources and ambient pressure/temperature operations is a breakthrough technology,which can reduce by over 90%the greenhouse gas emissions of this chemical and energy storage process.We report here an in-situ electrochemical activation method to prepare Fe2O3-CNT(iron oxide on carbon nanotubes)electrocatalysts for the direct ammonia synthesis from N2 and H2O.The in-situ electrochemical activation leads to a large increase of the ammonia formation rate and Faradaic efficiency which reach the surprising high values of 41.6μg mgcat^−1 h^−1 and 17%,respectively,for an in-situ activation of 3 h,among the highest values reported so far for non-precious metal catalysts that use a continuous-flow polymer-electrolytemembrane cell and gas-phase operations for the ammonia synthesis hemicell.The electrocatalyst was stable at least 12 h at the working conditions.Tests by switching N2 to Ar evidence that ammonia was formed from the gas-phase nitrogen.The analysis of the changes of reactivity and of the electrocatalyst characteristics as a function of the time of activation indicates a linear relationship between the ammonia formation rate and a specific XPS(X-ray-photoelectron spectroscopy)oxygen signal related to O2−in iron-oxide species.This results together with characterization data by TEM and XRD suggest that the iron species active in the direct and selective synthesis of ammonia is a maghemite-type iron oxide,and this transformation from the initial hematite is responsible for the in-situ enhancement of 3-4 times of the TOF(turnover frequency)and NH3 Faradaic efficiency.This transformation is likely related to the stabilization of the maghemite species at CNT defect sites,although for longer times of preactivation a sintering occurs with a loss of performances. 展开更多
关键词 Ammonia direct synthesis Electrochemical activation Heterogeneous catalysis Active sites N2 electrocatalytic conversion
下载PDF
Molecular Dynamics, Physical Properties, Diffusion Coefficients and Activation Energy of the Lithium Oxide (Li-O) and Sodium Oxide (Na-O) Electrolyte (Cathode)
10
作者 Alain Second Dzabana Honguelet Abel Dominique Eboungabeka Timothée Nsongo 《Advances in Materials Physics and Chemistry》 CAS 2024年第9期213-234,共22页
This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied ... This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied a gap-free model using molecular dynamics. Physical quantities such as volume and pressure of the Na-O and Li-O systems exhibit similar behaviors around the thermodynamic ensembles NPT and NVE. However, for the Na2O system, at a minimum temperature value, we observe a range of total energy values;in contrast, for the Li2O system, a minimum energy corresponds to a range of temperatures. Finally, for physicochemical properties, we studied the diffusion coefficient and activation energy of lithium and potassium oxides around their melting temperatures. The order of magnitude of the diffusion coefficients is given by the relation Dli-O >DNa-O for the multiplicity 8*8*8, while for the activation energy, the order is well reversed EaNa-O > EaLi-O. 展开更多
关键词 Molecular Dynamics Diffusion Coefficients activation Energy Lithium Oxide Sodium Oxide Lennard Jones Potential Data File Atomic and Charge Models CATHODE LAMMPS
下载PDF
New Insights in the Biodegradability and the Ecotoxicological Effects of Solar Products Containing Mineral and Chemical UV-Filters on Marine Zoo- and Phytoplanktons: An in silico and in vitro Study
11
作者 Jean-Claude Hubaud Karim Mekideche +1 位作者 Jean-Eric Branka Luc Lefeuvre 《Journal of Cosmetics, Dermatological Sciences and Applications》 2024年第1期98-111,共14页
Background: Cosmetic formulations, and particularly solar products which contain mineral and chemical UV-filters, are often suspected of causing harmful effects on marine fauna and flora. After the publication of our ... Background: Cosmetic formulations, and particularly solar products which contain mineral and chemical UV-filters, are often suspected of causing harmful effects on marine fauna and flora. After the publication of our work in 2019 concerning the ecotoxicological effects of such formulations on corals (Seriatopora hystrix), we here provide some new information about the biodegradability and the ecotoxicological effects of these products on marine zoo- and phytoplankton. Therefore, we choose to realize in silico and in vitro studies of the biodegradability of several solar products but also to evaluate the ecotoxicological effects of these products on one phytoplankton, i.e. Phaeodactylum tricornutum, and one zooplankton, i.e. Acartia tonsa, of a great importance for sea species survival (notably as sources of food). Materials and methods: Two different approaches were used to study the biodegradability of the tested products: One in silico method and an in vitro one. 2 solar products were involved in the in silico study which consisted in the determination of the degradation factor (DF) of each ingredient of the tested formulas in order to finally obtain their estimated biodegradability percentage. Already available data concerning each ingredient coupled to a computer model developed with one of our partners were used to achieve this study. The in vitro study involved 8 formulas containing UV-filters and was led by following the OECD 301 F guidelines. Ecotoxicological studies of 7 of the formulas containing UV-filters were for their part realized by following the ISO 10253 guidelines for the experiments led with Phaeodactylum tricornutum, and the ISO 14669 guidelines for the experiments led with Acartia tonsa. In these studies, the effect of each tested product on crustaceans’ mortality and algal growth inhibition was assessed. Results: The in silico study predicted that formulas containing chemical UV-filters display a high biodegradability (superior to the threshold value of 60% given by the OECD 301 F guidelines). In the in vitro part of our work, the 8 tested formulas showed a biodegradability slightly inferior to the one predicted in the in silico experiments. Therefore, in order to evaluate if these calculated biodegradability value could have significant harmful effects on zoo- or phytoplankton, we studied the effect of our products regarding the growth inhibition on Phaeodactylum tricornutum and the mortality on Acartia tonsa. In this last part of the study, all the tested products were classified as “non ecotoxic” following an internal classification based on Part 4 entitled “Environmental Hazards” of Globally Harmonized System of Classification and Labelling of Chemicals (GHS), 9<sup>th</sup> edition (2021). Conclusions: These results are notably in line with those published by our teams in 2019 on the effects of solar cosmetic products on corals and seem to confirm that formulas containing mineral and chemical UV-filters can be daily used without displaying significant noxious effects on marine fauna and flora. . 展开更多
关键词 UV-Filters chemical UV-Filter BIODEGRADABILITY ECOTOXICOLOGY in silico in vitro ZOOPLANKTON Phytoplankton Phaeodactylum tricornutum Acartia tonsa
下载PDF
Acetylene hydrochlorination over supported ionic liquid phase(SILP)gold-based catalyst:Stabilization of cationic Au species via chemical activation of hydrogen chloride and corresponding mechanisms 被引量:7
12
作者 Jia Zhao Saisai Wang +9 位作者 Bolin Wang Yuxue Yue Chunxiao Jin Jinyue Lu Zheng Fang Xiangxue Pang Feng Feng Lingling Guo Zhiyan Pan Xiaonian Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第2期334-346,共13页
The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination.Here,we report a strategy for activating HCl by the Au-based support... The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination.Here,we report a strategy for activating HCl by the Au-based supported ionic liquid phase(Au–SILP)technology with the[N(CN)2^–]anion.This strategy enables HCl to accept electrons from[N(CN)2^–]anions in Au–[N(CN)2^–]complexes rather than from pure[Bmim][N(CN)2],leading to notable improvement in both the reaction path and the stability of the catalyst without changing the reaction triggered by acetylene adsorption.Furthermore,the induction period of the Au–SILP catalyst was shown to be absent in the reaction process due to the high Au(III)content in the Au(Ⅲ)/Au(Ⅰ)site and the high substrate diffusion rate in the ionic liquid layer.This work provides a facile method to improve the stability of Au-based catalysts for acetylene hydrochlorination. 展开更多
关键词 Acetylene hydrochlorination Electron density Hydrogen chloride activation Stabilization mechanism Gold-based supported ionic liquid phase catalyst
下载PDF
Interactions of chemical carcinogens and genetic variation in hepatocellular carcinoma 被引量:1
13
作者 Yu-Jing Zhang 《World Journal of Hepatology》 CAS 2010年第3期94-102,共9页
In the etiology of hepatocellular carcinoma (HCC), in addition to hepatitis B virus and hepatitis C virus infections, chemical carcinogens also play important roles. For example, aflatoxin B 1 (AFB 1 ) epoxide reacts ... In the etiology of hepatocellular carcinoma (HCC), in addition to hepatitis B virus and hepatitis C virus infections, chemical carcinogens also play important roles. For example, aflatoxin B 1 (AFB 1 ) epoxide reacts with guanine in DNA and can lead to genetic changes. In HCC, the tumor suppressor gene p53 codon 249 mutation is associated with AFB 1 exposure and mutations in the K -ras oncogene are related to vinyl chloride exposure. Numerous genetic alterations accumulate during the process of hepatocarcinogenesis. Chemical carcinogen DNA-adduct formation is the basis for these genetic changes and also a molecular marker which reflects exposure level and biological effects. Metabolism of chemical carcinogens, including their activation and detoxification, also plays a key role in chemical hepatocarcinogenesis. Cytochrome p450 enzymes, N -acetyltransferases and glutathione S -transferases are involved in activating and detoxifying chemical carcinogens. These enzymes are polymorphic and genetic variation influences biological response to chemical carcinogens. This genetic variation has been postulated to influence the variability in risk for HCC observed both within and across populations. Ongoing studies seek to fully understand the mechanisms by which genetic variation in response to chemical carcinogens impacts on HCC risk. 展开更多
关键词 Hepatocellular carcinoma chemical CARCINOGENS AFLATOXIN B 1 POLYCYCLIC aromatic hydrocarbons 4-aminobiphenyl HEPATITIS B VIRUS HEPATITIS C VIRUS Glutathione S -transferase Cytochrome p450 enzymes Genetic variation
下载PDF
A Study of Superconducting La<sub>2</sub>CuO<sub>4</sub>via Generalized BCS Equations Incorporating Chemical Potential
14
作者 G. P. Malik V. S. Varma 《World Journal of Condensed Matter Physics》 2015年第3期148-159,共12页
We address the Tc (s) and multiple gaps of La2CuO4 (LCO) via generalized BCS equations incorporating chemical potential. Appealing to the structure of the unit cell of LCO, which comprises sub- lattices with LaO and O... We address the Tc (s) and multiple gaps of La2CuO4 (LCO) via generalized BCS equations incorporating chemical potential. Appealing to the structure of the unit cell of LCO, which comprises sub- lattices with LaO and OLa layers and brings into play two Debye temperatures, the concept of itinerancy of electrons, and an insight provided by Tacon et al.’s recent experimental work concerned with YBa2Cu3O6.6 which reveals that very large electron-phonon coupling can occur in a very narrow region of phonon wavelengths, we are enabled to account for all values of its gap-to-Tc ratio (2Δ0/kBTc), i.e., 4.3, 7.1, ≈8 and 9.3, which were reported by Bednorz and Müller in their Nobel lecture. Our study predicts carrier concentrations corresponding to these gap values to lie in the range 1.3 × 1021 - 5.6 × 1021 cm-3, and values of 0.27 - 0.29 and 1.12 for the gap-to-Tc ratios of the smaller gaps. 展开更多
关键词 GENERALIZED BCS EQUATIONS chemical Potential Two-Phonon Exchange Mechanism Structure of the Unit Cell of LCO Gap-to-Tc Ratio Effective Mass of Electrons Number Densities of Charge Carriers
下载PDF
Adsorption of Copper (II) Ions in Aqueous Solution by a Natural Mouka Smectite and an Activated Carbon Prepared from Kola Nut Shells by Chemical Activation with Zinc Chloride (ZnCl<sub>2</sub>)
15
作者 Phil Lewis Mpampoungou Langama Jean Jacques Anguile +2 位作者 Albert Novy Messi Me Ndong Adam Bouraima Crislain Bissielou 《Open Journal of Inorganic Chemistry》 2021年第4期131-144,共14页
The aim of this work was to test the adsorption efficiency of copper (II) ions in an aqueous solution on Natural Smectite (NS) and Activated Carbon (AC). The experiments carried out in batch mode made it possible to d... The aim of this work was to test the adsorption efficiency of copper (II) ions in an aqueous solution on Natural Smectite (NS) and Activated Carbon (AC). The experiments carried out in batch mode made it possible to determine the stirring time, the adsorbent mass, the pH, the initial concentration of copper (II) ions, the isotherms and the adsorption kinetics. It appears that the stirring time was 15 minutes for the AC and 20 minutes for the NS. The adsorption was at maximum for the two adsorbents at optimum pH of 3.5 for a mass of 0.05 g each. The quantity of copper (II) ions adsorbed was 26.6 mg/L for NS and 36.6 mg/g for AC of a concentration of 600 mg/L each. The Langmuir isotherm was the one that best described the adsorption process for the two adsorbents. The adsorption kinetics obtained was that of the pseudo second-order for our two adsorbents. The results obtained showed that these two adsorbents were effective for the adsorption of copper (II) ions in an aqueous solution. 展开更多
关键词 Batch Isotherm Kinetics ADSORPTION Activated Carbon Natural Smectite
下载PDF
Protection of Environment from Damaged Nuclear Station and Transparent Inflatable Blanket for Cities—Protection from Radioactive Dust and Chemical, Biological Weapons 被引量:1
16
作者 Alexander Bolonkin 《Journal of Environmental Protection》 2011年第4期327-341,共15页
The author, in a series of previous articles, designed the “AB Dome” made of transparent thin film supported by a small additional air overpressure for the purpose of covering a city or other important large install... The author, in a series of previous articles, designed the “AB Dome” made of transparent thin film supported by a small additional air overpressure for the purpose of covering a city or other important large installations or sub-regions. In present article the author offers a variation in which a damaged nuclear station can be quickly covered by such a cheap inflatable dome. By containing the radioactive dust from the damaged nuclear station, the danger zone is reduced to about 2 km2 rather than large regions which requires the resettlement of huge masses of people and which stops indus-try in large areas. If there is a big city (as Tokyo) near the nuclear disaster or there is already a dangerous amount of radioactive dust near a city, the city may also be covered by a large inflatable transparent Dome. The building of a gi-gantic inflatable AB Dome over an empty flat surface is not difficult. The cover is spread on a flat surface and a venti-lator (fan system) pumps air under the film cover and lifts the new dome into place but inflation takes many hours. However, to cover a city, garden, forest or other obstacle course in contrast to an empty, mowed field, the thin film cannot be easily deployed over building or trees without risking damage to it by snagging and other complications. This article proposes a new method which solves this problem. The design is a double film blanket filled by light gas such as, methane, hydrogen, or helium - although of these, methane will be the most practical and least likely to leak. Sections of this AB Blanket are lighter than air and will rise in the atmosphere. They can be made on a flat area serving as an as-sembly area and delivered by dirigible or helicopter to station at altitude over the city. Here they connect to the already assembled AB Blanket subassemblies, cover the city in an AB Dome and protect it from bad weather, chemical, bio-logical and radioactive fallout or particulates. After assembly of the dome is completed, the light gas can be replaced by (heavier but cheaper) air. Two projects for Tokyo (Japan) and Moscow (Russia) are used in this paper for sample computation. 展开更多
关键词 Radiation Shield PROTECTION Of Environment From Damaged NUCLEAR STATION Dome For City BLANKET For City PROTECTION Of CITIES From chemical Biological And RADIOACTIVE Weapons Encapsulating NUCLEAR Sites
下载PDF
Gene editing for corneal disease management
17
作者 Sudhanshu P Raikwar Apoorva S Raikwar +1 位作者 Shyam S Chaurasia Rajiv R Mohan 《World Journal of Translational Medicine》 2016年第1期1-13,共13页
Gene editing has recently emerged as a promising technology to engineer genetic modifications precisely in the genome to achieve long-term relief from corneal disorders.Recent advances in the molecular biology leading... Gene editing has recently emerged as a promising technology to engineer genetic modifications precisely in the genome to achieve long-term relief from corneal disorders.Recent advances in the molecular biology leading to the development of clustered regularly interspaced short palindromic repeats(CRISPRs) and CRISPR-associated systems,zinc finger nucleases and transcription activator like effector nucleases have ushered in a new era for high throughput in vitro and in vivo genome engineering.Genome editing can be successfully used to decipher complex molecular mechanisms underlying disease pathophysiology,develop innovative next generation gene therapy,stem cell-based regenerative therapy,and personalized medicine for corneal and other ocular diseases.In this review we describe latest developments in the field of genome editing,current challenges,and future prospects for the development of personalized genebased medicine for corneal diseases.The gene editing approach is expected to revolutionize current diagnostic and treatment practices for curing blindness. 展开更多
关键词 ADENO-ASSOCIATED virus Clustered Regularly-Interspaced SHORT Palindromic Repeats associated protein 9 Cornea Clustered regularly interspaced SHORT palindromic repeat Double strand breaks GENE EDITING sgRNA GENE targeting Homology directed repair Homologous recombination Indels LENTIVIRAL vector Protospacer-adjacent motif Transcription activator like effector NUCLEASES Zinc finger NUCLEASES
下载PDF
JTE-522-induced apoptosis in human gastric adenocarinoma cell line AGS cells by caspase activation accompanying cytochrome C release,membrane translocation of Bax and loss of mitochondrial membrane potential 被引量:16
18
作者 Hong-Liang Li Xiao-Hong Li Jun-Hua Lü Xian-Da Ren,Department of Pharmacology,Jinan University Pharmacy College,Guangzhou 510632,Guangdong Province,China Dan-Dan Chen,Department of Cardiology,First Affiliated Hospital,Zhongshan University,Guangzhou 510089,Guangdong Province,China Hai-Wei Zhang,Department of Pathology,Jinan University Medical College,Guangzhou 510632,Guangdong Province,China Cun-Chuan Wang,Department of laparoscopic surgery,First Affiliated Hospital,Jinan University Medical College,Guangzhou 510632,Guangdong Province,China 《World Journal of Gastroenterology》 SCIE CAS CSCD 2002年第2期217-223,共7页
AIM: To investigate the role of the mitochondrial pathway in JTE-522-induced apoptosis and to investigate the relationship between cytochrome C release, caspase activity and loss of mitochondrial membrane potential (D... AIM: To investigate the role of the mitochondrial pathway in JTE-522-induced apoptosis and to investigate the relationship between cytochrome C release, caspase activity and loss of mitochondrial membrane potential (Deltapsim). METHODS: Cell culture, cell counting, ELISA assay, TUNEL, flow cytometry, Western blot and fluorometric assay were employed to investigate the effect of JTE-522 on cell proliferation and apoptosis in AGS cells and related molecular mechanism. RESULTS: JTE-522 inhibited the growth of AGS cells and induced the apoptosis. Caspases 8 and 9 were activated during apoptosis as judged by the appearance of cleavage products from procaspase and the caspase activities to cleave specific fluorogenic substrates. To elucidate whether the activation of caspases 8 and 9 was required for the apoptosis induction, we examined the effect of caspase-specific inhibitors on apoptosis. The results showed that caspase inhibitors significantly inhibited the apoptosis induced by JTE-522. In addition, the membrane translocation of Bax and cytosolic release of cytochrome C accompanying with the decrease of the uptake of Rhodamin 123, were detected at an early stage of apoptosis. Furthermore, Bax translocation, cytochrome C release, and caspase 9 activation were blocked by Z-VAD.fmk and Z-IETD-CHO. CONCLUSION: The present data indicate a crucial association between activation of caspases 8, 9, cytochrome C release, membrane translocation of Bax, loss of Deltapsim and JTE-522-induced apoptosis in AGS cells. 展开更多
关键词 Adenocarcinoma Stomach Neoplasms Amino Acid Chloromethyl Ketones Anti-Inflammatory Agents Non-Steroidal Apoptosis BENZENESULFONATES CASPASES inhibitors Cyclooxygenase Inhibitors Cysteine Proteinase Inhibitors Cytochrome c Group Enzyme activation Humans In Situ Nick-End Labeling Membrane Potentials Mitochondria OXAZOLES Proto-Oncogene Proteins Proto-Oncogene Proteins c-bcl-2 Research Support Non-U.S. Gov't Tumor Cells Cultured bcl-2-Associated X Protein
下载PDF
Adsorption of Phenol by Activated Carbon Prepared from Waste Rice Straw by Chemical Activation with (NH_4)_2HPO_4 被引量:1
19
作者 高品 刘振鸿 +2 位作者 薛罡 韩彬 周美华 《Journal of Donghua University(English Edition)》 EI CAS 2011年第6期552-558,共7页
Activated carbons,RS-1,RS-2,and RS-3,prepared from rice straw with(NH4)2HPO4 activation were used as adsorbents for removing phenols from aqueous solutions.The maximum adsorption capacities of phenol for RS-1,RS-2,and... Activated carbons,RS-1,RS-2,and RS-3,prepared from rice straw with(NH4)2HPO4 activation were used as adsorbents for removing phenols from aqueous solutions.The maximum adsorption capacities of phenol for RS-1,RS-2,and RS-3 were 163.9,172.9,and 200.0 mg/g,respectively.The equilibrium data were analyzed by the Langmuir,Freundlich,and Temkin models.It displayed that Langmuir isotherm fitted to the results best.The dimensionless parameter RL indicated the favorable nature of the adsorption of phenol.Otherwise,the kinetic rates were well explained by pseudo-second-order model.According to the results,activated carbon derived from waste rice straw can be a high-performance adsorbent for wastewater treatment. 展开更多
关键词 activated carbon rice straw PHENOL (NH4)2HPO4 adsorption isotherm
下载PDF
Theory and Application of Numerical Simulation of Chemical Flooding in High Temperature and High Salt Reservoirs
20
作者 Yirang Yuan Aijie Cheng +1 位作者 Danping Yang Changfeng Li 《International Journal of Geosciences》 2014年第9期956-970,共15页
Applications, theoretical analysis and numerical methods are introduced for the simulation of mechanical models and principles of the porous flow in high temperature, high salt, complicated geology and large-scale res... Applications, theoretical analysis and numerical methods are introduced for the simulation of mechanical models and principles of the porous flow in high temperature, high salt, complicated geology and large-scale reservoirs in this paper. Considering petroleum geology, geochemistry, computational permeation fluid mechanics and computer technology, we state the models of permeation fluid mechanics and put forward a sequence of implicit upwind difference iteration schemes based on refined fractional steps of the upstream, which can compute the pressures, the saturation and the concentrations of different chemistry components. A type of software applicable in major industries has been completed and carried out in numerical analysis and simulations of oil extraction in Shengli Oil-field, which brings huge economic benefits and social benefits. This software gives many characters: spatial steps are taken as ten meters, the number of nodes is up to hundreds of thousands and simulation time period can be tens of years and the high-order accuracy can be promised in numerical data. Precise analysis is present for simplified models of this type and that provides a tool to solve the international famous problem. 展开更多
关键词 HIGH Temperature and HIGH SALT COMPLICATED chemical FLOODING Computational PERMEATION Fluid Mechanics Numerical Method and Engineering Software Actual Application of Oil-Fields Theoretical Analysis
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部