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Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Xingfu SONG, Shuying SUN, Dengke ZHANG, Jin WANG, Jianguo YU

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 416-421 doi: 10.1007/s11705-011-1125-9

摘要: Magnesium hydroxide with high purity and uniform particle size distribution was synthesized by the direct precipitation method using MgCl and NaOH as reactive materials and NaCl as additive to improve the crystallization behavior of the product. The particle size distribution, crystal phase, morphology, and surface area of magnesium hydroxide were characterized by Malvern laser particle size analyzer, X-ray diffraction (XRD), scanning electron microscope (SEM) and Branauer-Emmett-Teller (BET) method, respectively. The purity of products was analyzed by the chemical method. The effects of synthesis conditions on the particle size distribution and water content (filtration cake) of magnesium hydroxide were investigated. The results indicated that feeding mode and rate, and reaction temperature had important effects on water content and the particle size distribution of the product, and sodium chloride improved the crystallization behavior of magnesium hydroxide. The ball-like magnesium hydroxides with the particle size distribution of 6.0–30.0 μm and purity higher than 99.0% were obtained. This simple and mild synthesis method was promising to be scaled up for the industrial production of magnesium hydroxide.

关键词: magnesium hydroxide     direct precipitation method     industrial crystallization     particle size distribution    

Preparation and crystallization kinetics of micron-sized Mg(OH)

Xingfu SONG, Kefeng TONG, Shuying SUN, Ze SUN, Jianguo YU

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 130-138 doi: 10.1007/s11705-013-1332-7

摘要: Magnesium hydroxide is an important chemical, and is usually obtained from seawater or brine via precipitation process. The particle size distribution of magnesium hydroxide has great effects on the subsequent filtration and drying processes. In this paper, micron-sized magnesium hydroxide with high purity, large particle size and low water content in filter cake was synthesized via simple wet precipitation in a mixed suspension mixed product removal (MSMPR) crystallizer. The effects of reactant concentration, residence time and impurities on the properties of magnesium hydroxide were investigated by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Malvern laser particle size analyzer. The results show that NaOH concentration and residence time have great effects on the water content and particle size of Mg(OH) . The spherical Mg(OH) with uniform diameter of about 30 μm was obtained with purity higher than 99% and water content less than 31%. Furthermore, the crystallization kinetics based on the population balance theory was studied to provide the theoretical data for industrial enlargement, and the simulation coefficients ( ) based on ASL model and C-R model are 0.9962 and 0.9972, respectively, indicating that the crystal growth rate of magnesium hydroxide can be well simulated by the size-dependent growth models.

关键词: magnesium hydroxide     precipitation     micron-sized     crystallization kinetics    

Local arc discharge mechanism and requirements of power supply in micro-arc oxidation of magnesium alloy

Ming CHEN, Yuezhou MA, Yuan HAO,

《机械工程前沿(英文)》 2010年 第5卷 第1期   页码 98-105 doi: 10.1007/s11465-009-0088-8

摘要: To study the requirements of the power supply in micro-arc oxidation (MAO) of magnesium alloy, many experiments were performed under the DC, unipolar, and ambipolar pulse output modes. Based on the experimental results and electric arc theory, the separate local arc discharge mechanism was put forward. It is considered that magnesium MAO process consists of three stages including anodic oxidation, micro-arc oxidation, and large-arc discharge in turn with increasing source voltage. The MAO film is composed of metal oxides that resulted from numerous discrete local arc discharges, which accumulate the non-equilibrium structure after undergoing sudden heating and cooling cycles. Separate local arc discharge is caused by the process in which the oxygen-based gas is ionized in the conduct channel bearing electric field intensity, changed from insulator to conductor that presents sharp negative resistance effect, and produced partially high temperature to ignite locally metal oxidation. The local arc discharge model is described as four courses: gas created from electrolysis, arc discharge, metals oxidization, and cooling and shrinking of oxides. The purpose of pulse supply is to inhibit the large-arc discharge by intervening proper cooling time, which cannot be actualized by a unipolar pulse mode because of the strong capacitive load characteristics but can be reached by an ambipolar pulse supply because the negative pulse period acts as cooling time. Using a discharge loop to remove the influence of load capacitive, a new type of pulse power supply for MAO is developed, so that the large-arc problem is resolved effectively, the film-forming efficiency is improved, and the pollution of the film and electrolyte caused by negative voltage is avoided.

关键词: micro-arc oxidation     local arc discharge     pulse power supply     magnesium alloy    

Experimental study on mechanical properties of a novel micro-steel fiber reinforced magnesium phosphate

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1047-1057 doi: 10.1007/s11709-021-0755-3

摘要: Magnesium phosphate cement (MPC) received increased attention in recent years, but MPC-based concrete is rarely reported. The micro-steel fibers (MSF) were added to MPC-based concrete to enhance its ductility due to the high brittleness in tensile and flexural strength properties of MPC. This paper investigates the effect of MSF volume fraction on the mechanical properties of a new pattern of MPC-based concrete. The temperature development curve, fluidity, cubic compressive strength, modulus of elastic, axial compressive strength, and four-point flexural strength were experimentally studied with 192 specimens, and a scanning electron microscopy (SEM) test was carried out after the specimens were failed. Based on the test results, the correlations between the cubic compressive strength and curing age, the axial and cubic compressive strength of MPC-based concrete were proposed. The results showed that with the increase of MSF volume fraction, the fluidity of fresh MPC-based concrete decreased gradually. MSF had no apparent influence on the compressive strength, while it enhanced the four-point flexural strength of MPC-based concrete. The four-point flexural strength of specimens with MSF volume fraction from 0.25% to 0.75% were 12.3%, 21.1%, 24.6% higher than that of the specimens without MSF, respectively.

关键词: magnesium phosphate cement-based concrete     micro-steel fibers     four-point flexural strength     compressive strength    

Effects of operational and structural parameters on cell voltage of industrial magnesium electrolysis

Ze Sun,Chenglin Liu,Guimin Lu,Xingfu Song,Jianguo Yu

《化学科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 522-531 doi: 10.1007/s11705-015-1539-x

摘要: Electric field is the energy foundation of the electrolysis process and the source of the multiphysical fields in a magnesium electrolysis cell. In this study, a three-dimensional numerical model was developed and used to calculate electric field at the steady state through the finite element analysis. Based on the simulation of the electric field, the operational and structural parameters, such as the current intensity, anode thickness, cathode thickness, and anode-cathode distance (ACD), were investigated to obtain the minimum cell voltage. The optimization is to obtain the minimum resistance voltage which has a significant effect on the energy consumption in the magnesium electrolysis process. The results indicate that the effect of the current intensity on the voltage could be ignored and the effect of the ACD is obvious. Moreover, there is a linear decrease between the voltage and the thicknesses of the anode and cathode; and the anode-cathode working height also has a significant effect on the voltage.

关键词: finite element method     magnesium electrolysis cell     electric field    

Green process to recover magnesium chloride from residue solution of potassium chloride production plant

WANG Lin, HE Yunliang, WANG Yanfei, BAO Ying, WANG Jingkang

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 385-389 doi: 10.1007/s11705-008-0079-z

摘要: The green process to recover magnesium chloride from the residue solution of a potassium chloride production plant, which comes from the leach solution of a potash mine in Laos, is designed and optimized. The residue solution contains magnesium chloride above 25 wt-%, potassium chloride and sodium chloride together below 5 wt-% and a few other ions such as Br, SO and Ca. The recovery process contains two steps: the previous impurity removal operation and the two-stage evaporation-cooling crystallization procedure to produce magnesium chloride. The crystallized impurity carnallite obtained from the first step is recycled to the potassium chloride plant to recover the potassium salt. The developed process is a zero discharge one and thus fulfills the requirements for green chemical industrial production. The produced magnesium chloride is up to industrial criteria.

关键词: industrial production     chemical industrial     produced magnesium     chloride production     impurity carnallite    

Noble-metal-free cobalt hydroxide nanosheets for efficient electrocatalytic oxidation

Jie Lan, Daizong Qi, Jie Song, Peng Liu, Yi Liu, Yun-Xiang Pan

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 948-955 doi: 10.1007/s11705-020-1920-2

摘要: Cobalt hydroxide has been emerging as a promising catalyst for the electrocatalytic oxidation reactions, including the oxygen evolution reaction (OER) and glucose oxidation reaction (GOR). Herein, we prepared cobalt hydroxide nanoparticles (CoHP) and cobalt hydroxide nanosheets (CoHS) on nickel foam. In the electrocatalytic OER, CoHS shows an overpotential of 306 mV at a current density of 10 mA·cm . This is enhanced as compared with that of CoHP (367 mV at 10 mA·cm ). In addition, CoHS also exhibits an improved performance in the electrocatalytic GOR. The improved electrocatalytic performance of CoHS could be due to the higher ability of the two-dimensional nanosheets on CoHS in electron transfer. These results are useful for fabricating efficient catalysts for electrocatalytic oxidation reactions.

关键词: electrocatalytic oxidation     cobalt hydroxide     nanosheet     water     glucose    

Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered double hydroxide

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1593-1607 doi: 10.1007/s11705-023-2348-2

摘要: With increasing emphasis on green chemistry, biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials. Herein, a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition. This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose. With the synergistic effect of three heterogeneous components, the electrode achieves outstanding glucose sensing performance, including a high sensitivity (851.4 µA·mmol−1·L·cm−2), a short response time (2.2 s), a wide linear range (two stages: 0.001−8.145 and 8.145−35.500 mmol·L−1), strong immunity to interference, outstanding intraelectrode and interelectrode reproducibility, a favorable toxicity resistance (Cl), and a good long-term stability (maintaining 86.0% of the original value after 30 d). These data are superior to those of some traditional glucose sensors using nonbiomass substrates. When determining the blood glucose level of a human serum, this electrode realizes a high recovery rate of 97.07%–98.89%, validating the potential for high-performance blood glucose sensing.

关键词: cellulose nanofibril     aerogel     nickel-cobalt layered double hydroxide     polypyrrole     nonenzymatic glucose sensor    

Filtration ability of hollow fiber membrane for production of magnesium ammonium phosphate crystals by

H. Watamura, H. Marukawa, I. Hirasawa

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 55-59 doi: 10.1007/s11705-013-1312-y

摘要: Relationship between magnesium ammonium phosphate (MAP) crystal properties and the filtration ability of hollow fiber membrane (HFM) were investigated. Phosphorus recovery process by crystallization has a problem that it produces a large amount of fine crystals. So improvement of the crystallization process by combining with filtration was discussed. MAP crystals were obtained by batch reaction crystallization and the filtration characteristics were investigated. The filtration was evaluated by the specific filtration resistance ( ) on HFM. Filtered slurry was prepared with each suspension density and crystal size distribution. The solution was filtered at constant pressure of 0.02 MPa and the filtration time on each filtrated volume was recorded. As a result, decreases exponentially with suspension density increasing from 0.25 g/L to 0.5 g/L and decreases moderately with suspension density increasing from 0.5 g/L to 1.5 g/L. of large crystals decreases exponentially at less suspension density than of small crystals does. Also, increases as the ratio of the fractured crystals increases.

关键词: membrane separation     crystallization     MAP    

Capture of carbon dioxide over porous solid adsorbents lithium silicate, lithium aluminate and magnesium

P. V. Korake, A. G. Gaikwad

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 215-226 doi: 10.1007/s11705-010-1012-9

摘要: The capturing process for carbon dioxide over porous solid adsorbents such as lithium silicate, lithium aluminate, and magnesium aluminate at pre- combustion temperatures was studied. Lithium silicate was prepared by the sol gel and solid fusion methods. The lithium silicate adsorbent was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and surface area. The capturing of carbon dioxide over lithium silicate, lithium aluminate, and magnesium aluminate was explored at different experimental conditions such as exposure time, temperature variation, and exposure carbon dioxide pressure. The capturing process for carbon dioxide was investigated over these adsorbents with variation of their metal mole ratios. The effect of the addition of (promoter) sodium, potassium, and cesium in the lithium silicate adsorbent was explored to investigate the variation of the capture of carbon dioxide over these adsorbents.

关键词: capturing CO2     lithium silicate     lithium aluminate     magnesium aluminate    

A stepwise process for carbon dioxide sequestration using magnesium silicates

Johan FAGERLUND, Experience NDUAGU, Ron ZEVENHOVEN, Inês ROMÃO,

《化学科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 133-141 doi: 10.1007/s11705-009-0259-5

摘要: This work involves the production of magnesium in the form of Mg(OH) from serpentinite rock (nickel mine tailing) material followed by conversion into MgCO using a pressurised fluidised bed (PFB) reactor operating at 400°C–600°C and pressures up to 2.85MPa. Our approach is rooted in the thermodynamic fact that the reaction between Mg(OH) and gaseous CO forming MgCO and water releases significant amounts of heat. The main problem is, however, the chemical kinetics; the reaction is slow and has to be accelerated in order to be used in an economically viable process for large-scale (~1Mt/a) CO sequestration. We have constructed a lab-scale PFB reactor test-setup for optimising the carbonation reaction. At high enough temperatures and conversion levels the reaction should provide the heat for the proceeding Mg(OH) production step, making the overall process energy neutral. So far we have been able to achieve a conversion degree of 26% at 500°C and 2.85MPa after 30min (particle size 125–212μm). In this paper the test facility and our latest results and progress on CO mineral carbonation are summarised. Also, the possible integration of the iron as a feedstock for iron and steel production will be briefly addressed. An interesting side-effect of this carbon dioxide capture and storage (CCS) route is that significant amounts of iron are obtained from the serpentinite rock material. This is released during the Mg(OH) production and can be of great interest to the iron- and steel producing sector, which at the same time is Finland’s largest CO producer.

关键词: carbonation reaction     reactor     producer     large-scale     process    

我国先进镁合金材料产业2035发展战略研究

李芳,管仁国,铁镝,刘楚明,乐启炽,宋江凤,曾小勤,蒋斌

《中国工程科学》 2020年 第22卷 第5期   页码 76-83 doi: 10.15302/J-SSCAE-2020.05.014

摘要:

本文在梳理我国镁合金材料产业发展现状的基础上,分析了其发展面临的国内外主要问题,展望了我国镁合金材料产业在高性能稀土镁轻质结构合金材料、高强高导热镁合金材料、高强高导电镁合金材料、超高强镁合金材料等11个方面的未来市场需求前景。面向2030年和2035年的阶段性发展规划,本文从提高自主创新能力、优化资源配置、加强企业合作力度、构建完善的镁合金材料整体研究体系、完善平台建设等方面提出了促进我国先进镁合金材料产业可持续发展的相关战略。最后,从注重研究体系的构建、优化产业发展格局、构建高质高效产业、完善配套政策体系、构建精尖人才体系等方面提出了对策建议,以期满足国民经济、国家重大工程和社会可持续发展对先进镁合金材料的需求。

关键词: 金属材料产业     镁合金     稀土镁合金材料     低能耗     高效率     2035    

Layered double hydroxide-based core-shell nanoarrays for efficient electrochemical water splitting

Wenfu Xie, Zhenhua Li, Mingfei Shao, Min Wei

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 537-554 doi: 10.1007/s11705-018-1719-6

摘要:

Electrochemical water splitting is an efficient and clean strategy to produce sustainable energy productions (especially hydrogen) from earth-abundant water. Recently, layered double hydroxide (LDH)-based materials have gained increasing attentions as promising electrocatalysts for water splitting. Designing LDHs into hierarchical architectures (e.g., core-shell nanoarrays) is one of the most promising strategies to improve their electrocatalytic performances, owing to the abundant exposure of active sites. This review mainly focuses on recent progress on the synthesis of hierarchical LDH-based core-shell nanoarrays as high performance electrocatalysts for electrochemical water splitting. By classifying different nanostructured materials combined with LDHs, a number of LDH-based core-shell nanoarrays have been developed and their synthesis strategies, structural characters and electrochemical performances are rationally described. Moreover, further developments and challenges in developing promising electrocatalysts based on hierarchical nanostructured LDHs are covered from the viewpoint of fundamental research and practical applications.

关键词: layered double hydroxides (LDHs)     core-shell nanoarrays     oxygen evolution reaction (OER)     hydrogen evolution reaction (HER)     photoelectrochemical water splitting (PEC)    

Defective Nickle–Iron Layered Double Hydroxide for Enhanced Photocatalytic NO Oxidation with Significant

Xiaoyu Li,Xiaoshu Lv,Jian Pan,Peng Chen,Huihui Peng,Yan Jiang,Haifeng Gong,Guangming Jiang,Li'an Hou,

《工程(英文)》 doi: 10.1016/j.eng.2023.06.017

摘要: Photocatalysis offers a sustainable avenue for the oxidative removal of low concentrations of NOx from the atmosphere. Layered double hydroxides (LDHs) are promising candidate photocatalysts owing to their unique layered and tunable chemical structures, and the abundant hydroxide (OH−) moieties on their surfaces that are hydroxyl radical (•OH) precursors. However, inferior charge separation and limited active sites on an LDH hinder its practical applications. Herein, we developed a facile N2H4-driven etching (et) approach that introduces dual Ni2+ and OH− vacancies (Niv and OHv) into NiFe-LDH nanosheets (referred to as NiFe-LDH-et) that facilitate improved charge-carrier separation and the formation of active Lewis acidic sites (Fe3+ and Ni2+ exposed at OHv). In contrast to inert pristine LDH, NiFe-LDH-et actively removes NO when illuminated with visible light. Specifically, Ni76Fe24-LDH-et etched in 1.50 mmol·L−1 N2H4 solution removes 32.8% of the NO from continuously flowing air (NO-feed concentration: ∼500 parts per billion (ppb)) when illuminated with visible light, thereby outperforming most reported catalysts. Experimental and theoretical data reveal that the dual vacancies promote the production of reactive oxygen species (•O2− and •OH) and the adsorption of NO on the LDH. In-situ spectroscopy revealed that NO is preferentially adsorbed at Lewis acidic sites, particularly exposed Fe3+ sites, and then converted into NO+ that is subsequently oxidized to NO3− without the formation of any of the more toxic NO2 intermediate, thereby alleviating risks associated with its production and emission.

关键词: Vacancies     Layered double hydroxide     NO     +     Photocatalysis     NO removal    

Protein phosphatase magnesium-dependent 1δ is a novel tumor marker and target in hepatocellular carcinoma

null

《医学前沿(英文)》 2016年 第10卷 第1期   页码 52-60 doi: 10.1007/s11684-016-0433-3

摘要:

Hepatocellular carcinoma (HCC) is a lethal liver malignancy worldwide. In this study, we reported that protein phosphatase magnesium-dependent 1δ (PPM1D) was highly expressed in the majority of HCC cases (approximately 59%) and significantly associated with high serum α-fetoprotein (AFP) level (P= 0.044). Kaplan-Meier and Cox regression data indicated that PPM1D overexpression was an independent predictor of HCC-specific overall survival (HR, 2.799; 95% CI, 1.346–5.818, = 0.006). Overexpressing PPM1D promoted cell viability and invasion, whereas RNA interference-mediated knockdown of PPM1D inhibited proliferation, invasion, and migration of cultured HCC cells. In addition, PPM1D suppression by small interfering RNA decreased the tumorigenicity of HCC cells in vivo. Overall, results suggest that PPM1D is a potential prognostic marker and therapeutic target for HCC.

关键词: PPM1D     hepatocellular carcinoma     prognosis     target therapy    

标题 作者 时间 类型 操作

Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Xingfu SONG, Shuying SUN, Dengke ZHANG, Jin WANG, Jianguo YU

期刊论文

Preparation and crystallization kinetics of micron-sized Mg(OH)

Xingfu SONG, Kefeng TONG, Shuying SUN, Ze SUN, Jianguo YU

期刊论文

Local arc discharge mechanism and requirements of power supply in micro-arc oxidation of magnesium alloy

Ming CHEN, Yuezhou MA, Yuan HAO,

期刊论文

Experimental study on mechanical properties of a novel micro-steel fiber reinforced magnesium phosphate

期刊论文

Effects of operational and structural parameters on cell voltage of industrial magnesium electrolysis

Ze Sun,Chenglin Liu,Guimin Lu,Xingfu Song,Jianguo Yu

期刊论文

Green process to recover magnesium chloride from residue solution of potassium chloride production plant

WANG Lin, HE Yunliang, WANG Yanfei, BAO Ying, WANG Jingkang

期刊论文

Noble-metal-free cobalt hydroxide nanosheets for efficient electrocatalytic oxidation

Jie Lan, Daizong Qi, Jie Song, Peng Liu, Yi Liu, Yun-Xiang Pan

期刊论文

Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered double hydroxide

期刊论文

Filtration ability of hollow fiber membrane for production of magnesium ammonium phosphate crystals by

H. Watamura, H. Marukawa, I. Hirasawa

期刊论文

Capture of carbon dioxide over porous solid adsorbents lithium silicate, lithium aluminate and magnesium

P. V. Korake, A. G. Gaikwad

期刊论文

A stepwise process for carbon dioxide sequestration using magnesium silicates

Johan FAGERLUND, Experience NDUAGU, Ron ZEVENHOVEN, Inês ROMÃO,

期刊论文

我国先进镁合金材料产业2035发展战略研究

李芳,管仁国,铁镝,刘楚明,乐启炽,宋江凤,曾小勤,蒋斌

期刊论文

Layered double hydroxide-based core-shell nanoarrays for efficient electrochemical water splitting

Wenfu Xie, Zhenhua Li, Mingfei Shao, Min Wei

期刊论文

Defective Nickle–Iron Layered Double Hydroxide for Enhanced Photocatalytic NO Oxidation with Significant

Xiaoyu Li,Xiaoshu Lv,Jian Pan,Peng Chen,Huihui Peng,Yan Jiang,Haifeng Gong,Guangming Jiang,Li'an Hou,

期刊论文

Protein phosphatase magnesium-dependent 1δ is a novel tumor marker and target in hepatocellular carcinoma

null

期刊论文