检索结果-南通市图书馆

Balanced Fracturing and Cold-welding of Magnesium during Ball Milling Assisted by Carbon Coating:Experimental and Molecular Dynamic Simulation

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 895-903页

作者：韩宗盈 dong Hui DING Guoyang ZHANG Jiale SONG xiufang College of Energy Storage Technology Shandong University of Science and TechnologyQingdao 266590China College of Chemical and Biological Engineering Shandong University of Science and TechnologyQingdao 266590China

The lignite-derived carbon from self-protection pyrolysis was employed to balance the fracturing and cold-welding of magnesium during ball milling.Particle size analysis indicates that the introduction of lignite-derived carbon can effectively reduce the particle size of Mg while the introduction of graphite does no help.Besides,the effect of lignite-derived carbon on crystallite size reduction of Mg is also better than graphite.A moderate cold-welding phenomenon was observed after ball-milling Mg with the lignite-derived carbon,suggesting less Mg is wasted on the milling vials and balls.Molecular dynamic simulations reveal that the balanced fracturing and cold-welding of magnesium during ball milling is mainly attributed to the special structure of the lignite-derived carbon:graphitized short-range ordered stacking function as dry lubricant and irregular shape/sharp edge function as milling aid.The preliminary findings in current study are expected to offer implications for designing efficient Mg-based hydrogen storage materials.

关键词： magnesium lignite-derived carbon cold-welding ball milling molecular dynamic

Synthesis and Characterization of Hollow Strontium Carbonate Pompons by Composite Soft Template Method

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1434-1439页

作者： LI Bibo dong xiufang LI Yu SONG Jian XIE Wuxi ZHANG Wei LIU Yunfei School of Environment and Safety Engineering North University of ChinaTaiyuan 030051China School of Chemical Engineering and Technology North University of ChinaTaiyuan 030051China Xi'an Modern Chemistry Research Institute Xi'an 710065China

The hollow strontium carbonate pompons was synthesized for the first time by a controlled reaction precipitation method with sodium dodecyl benzene sulfonate(SDBS)and polyvinyl pyrrolidone(PVP)work together as template.The sampled particles were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),nitrogen adsorption-desorption measurement,X-ray diffraction(XRD),Energy dispersive X-Ray spectroscopy(EDX),Fourier transform infrared spectroscopy(FTIR),Thermogravimetric analysis and differential scanning calorimetry(TGA-DSC),etc.It is shown that the assynthesized hollow strontium carbonate pompons with the size of about 2μm consist of flake-like particles under the optimal reaction conditions.The formation mechanism of hollow strontium carbonate pompons was preliminarily explored.

关键词： strontium carbonate hollow structure pompons composite soft template method

在线全文

学校读者我要写书评

暂无评论

一种用于波导中传动轴的级联宽带扼流装置

强激光与粒子束 2024年第8期36卷 70-75页

作者：董涛王秀芳倪泰来王皓王邦继刘庆想西南交通大学物理科学与技术学院成都610031

为了抑制波导中引入传动轴导致的微波泄露,保障系统的正常运行,提出了一种级联宽带扼流装置。利用阻抗变换原理分析了级联宽带扼流装置的带宽特性,通过增加介质片的数量提升扼流装置的频带宽度。根据等效波长原理,提高介质片介电常数可... 详细信息

为了抑制波导中引入传动轴导致的微波泄露,保障系统的正常运行,提出了一种级联宽带扼流装置。利用阻抗变换原理分析了级联宽带扼流装置的带宽特性,通过增加介质片的数量提升扼流装置的频带宽度。根据等效波长原理,提高介质片介电常数可缩小扼流装置的体积。通过电磁仿真软件构建扼流装置模型,并分析了介质片数量、介电常数和尺寸对扼流装置性能的影响。仿真结果表明:工作频率为10 GHz时,双层扼流装置的泄露损耗在9.70~10.82 GHz带宽范围内小于-40 dB,相对带宽达到8.2%。最后,采用简化仿真模型进行了实物加工和测试,测试结果证实了仿真结果的正确性,同时验证了该扼流装置的低损耗和宽频带特性。

关键词：扼流装置宽带级联传动轴波导

Tribological Performance of Different Concentrations of Al_(2)O_(3)Nanofluids on Minimum Quantity Lubrication Milling

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2023年第4期36卷 67-78页

作者： xiufang Bai Juan Jiang Changhe Li Lan dong Hafiz Muhammad Ali Shubham Sharma School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520China School of Mechanical and Electrical Engineering Qingdao Binhai UniversityQingdao 266555China Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia Department of Mechanical Engineering IK Gujral Punjab Technical UniversityMain Campus-KapurthalaJalandhar 144603India

Nanofluid minimum quantity lubrication(NMQL)is a green processing technology.Cottonseed oil is suitable as base oil because of excellent lubrication performance,low freezing temperature,and high yield.Al_(2)O_(3)nanoparticles improve not only the heat transfer capacity but also the lubrication performance.The physical and chemical proper-ties of nanofluid change when Al_(2)O_(3)nanoparticles are added.However,the effects of the concentration of nanofluid on lubrication performance remain unknown.Furthermore,the mechanisms of interaction between Al_(2)O_(3)nanoparti-cles and cottonseed oil are unclear.In this research,nanofluid is prepared by adding different mass concentrations of Al_(2)O_(3)nanoparticles(0,0.2%,0.5%,1%,1.5%,and 2%wt)to cottonseed oil during minimum quantity lubrication(MQL)milling 45 steel.The tribological properties of nanofluid with different concentrations at the tool/workpiece interface are studied through macro-evaluation parameters(milling force,specific energy)and micro-evaluation parameters(surface roughness,micro morphology,contact angle).The result show that the specific energy is at the minimum(114 J/mm^(3)),and the roughness value is the lowest(1.63μm)when the concentration is 0.5 wt%.The surfaces of the chip and workpiece are the smoothest,and the contact angle is the lowest,indicating that the tribological proper-ties are the best under 0.5 wt%.This research investigates the intercoupling mechanisms of Al_(2)O_(3)nanoparticles and cottonseed base oil,and acquires the optimal Al_(2)O_(3)nanofluid concentration to receive satisfactory tribological properties.

关键词： Milling Al_(2)O_(3)nanofluid Minimum quantity lubrication(MQL) Surface micromorphology

东莞市河道底泥特征及作为绿化种植土的可行性研究

在线全文

学校读者我要写书评

暂无评论

中国农学通报 2024年第5期40卷 69-73页

作者：董瑶俞胡伟刘智硕赵秀芳戎郁萍中国农业大学草业科学与技术学院北京100193 岭南生态文旅股份有限公司广东东莞523125

在广东东莞市沙田镇西太隆河流域综合整治工程中,为解决疏浚污染底泥的后续处理问题,对西太隆河上游、中下游河流交汇处、下游底泥的基本特性进行调查,分析将其改良为绿化种植土的可行性。结果表明:西太隆河底泥的pH值范围在pH 6.45~7.... 详细信息

在广东东莞市沙田镇西太隆河流域综合整治工程中,为解决疏浚污染底泥的后续处理问题,对西太隆河上游、中下游河流交汇处、下游底泥的基本特性进行调查,分析将其改良为绿化种植土的可行性。结果表明:西太隆河底泥的pH值范围在pH 6.45~7.35,渗透率范围在2.17×10^(-4)~8.9×10^(-4) cm/s,土壤质地为粉壤土,上述指标均符合CJ/T 340—2016城镇建设行业标准。该河道底泥养分含量充足但空间异质性较大,靠近下游的底泥养分含量远高于上游河段。靠近河道下游区域受到周围工厂的影响,底泥中的重金属元素含量高,Ni、Cu元素超标严重,未达到种植土的重金属含量最低标准。综合分析上游的河道底泥特性更符合CJ/T 340—2016标准,可通过改良用作绿化种植土,对城市水体环境治理具有重要意义。

关键词：河道底泥理化性质重金属可行性生态治理

Co-Ni Electromagnetic Coupling in Hollow Mo_(2)C/NC Sphere for Enhancing Electromagnetic Wave Absorbing Performance

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第1期41卷 64-74页

作者： xiufang Yang Wenming Gao Jiamin Chen Xing Lu dong Yang Yifan Kang Qi Liu Yuchang Qing Wenhuan Huang Key Laboratory of Chemical Additives for China National Light Industry College of Chemistry and Chemical EngineeringShaanxi University of Science and TechnologyXi'anShaanxi 710021China Northwest Institute of Mechanical and Electrical Engineering XianyangShaanxi 712099China State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'anShaanxi 710072China

For enhancing the electromagnetic wave(EW)attenuation and adsorption,rational constructing and homogeneously distributing bimetallic electromagnetic coupling units in hollow structure is an effective way,but hard to achieve.Herein,a CoNi-doped hybrid zeolite imidazole framework was synthesized as precursor,which was further converted into a hollow CoNi-bimetallic doped molyb-denum carbide sphere(H-CoNi@MoC/NC)through a two-step etching and calcination strategy.At the loading amount of 15 wt%,a strong absorption of minimum reflection loss(RL_(min))of-60.05 dB at 7.2 GHz with the thickness of 3.1 mm and a wide effective ad-sorption bandwidth(EAB)of 3.52 GHz at the thickness of 2.5 mm were achieved,which was far beyond the reported MoC-based metallic hybrids.The crucial synergistic Co-Ni electromagnetic coupling effect in the composite was characterized,not only enhanc-ing the dipolar/interfacial polarization,but also promoting the impedance matching,displaying the optimized EW absorbing perfor-mance.

关键词： Electromagnetic wave absorbing materials Hollow structure Hybrid zeolite imidazolate frameworks Microwave absorption Electromagnetic coupling

Anti-epileptic effects of neuropeptide Y gene transfection into the rat brain

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2013年第14期8卷 1307-1315页

作者： Changzheng dong Wenqing Zhao Wenling Li Peiyuan Lv xiufang dong Faculty of Graduate Studies Hebei Medical University Department of Functional Neurosurgery Hebei General Hospital Department of Neurology Hebei General Hospital Department of Neurology First Hospital of Xingtai

Neuropeptide Y gene transfection into normal rat brain tissue can provide gene overexpression, which can attenuate the severity of kainic acid-induced seizures. In this study, a recombinant adeno-associated virus carrying the neuropeptide Y gene was transfected into brain tissue of rats with kainic acid-induced epilepsy through stereotactic methods. Following these transfections, we verified overexpression of the neuropeptide Y gene in the epileptic brain. Electroencephalograms showed that seizure severity was significantly inhibited and seizure latency was significantly prolonged up to 4 weeks after gene transfection. Moreover, quantitative fluorescent PCR and western blot assays revealed that the mRNA and protein expression of the N-methyI-D-aspartate receptor subunits NR1, NR2A, and NR2B was inhibited in the hippocampus of epileptic rats. These findings indicate that neuropeptide Y may inhibit seizures via down-regulation of the functional expression of N-methyI-D-aspartate receptors.

关键词： neural regeneration brain injury gene therapy adeno-associated virus neuropeptide Y epilepsy N-methyI-D-aspartate receptor kainic acid seizures neuroregeneration

Synthesis and characterization of super paramagnetic composite photocatalyst-Titania/silica/nickel ferrite

在线全文

学校读者我要写书评

暂无评论

Particuology 2011年第5期9卷 475-479页

作者： Yu Li xiufang dong Junping Li School of Chemical Engineering and Environment North University of China Taiyuan 030051 Shanxi China

Composite photocatalysts with TiO2 porous shell and magnetic core were synthesized by using NiFe2O4 as a magnetic core, SiO2 as an intermediate layer and polyethylene glycol with molecular weight of 1000 （PEG 1000） as a template direction agent. The samples were characterized with N2 adsorption-desorption, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, vibrating sample magnetometry （VSM） and ultraviolet-visible （UV-vis） spectroscopy. The results showed that the obtained composites are spherical particles about 50 nm in diameter. The mesoporous TiO2 with magnetic core calcined at 350 ℃, 450 ℃, and 550 ℃ was found to have, respectively, different specific surface areas （94, 86, and 68 m^2/g） and average pore sizes （1.4, 2.2, and 2.8 nm）. The photocatalytic activity was investigated for degradation of nitrobenzene under UV irradiation. Nitrobenzene was decomposed in 300 min under irradiation of an 8 W UV lamp with a peak wavelength of 253.7 nm. The composite nanoparticles exhibited high photocatalytic efficiency and super paramagnetic nature for cleaning polluted water by magnetic separation.

关键词： Titania Mesoporous Photocatalyst Core-shell

Low-Angle Grain Boundaries in Sublimation Grown 6H-SiC Crystals

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第Z1期24卷 8-10页

作者： Jiang Shouzhen Li Xianxiang dong Jie Chen xiufang Xu Xiangang Hu Xiaobo State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

High-resolution X-ray diffractometry (HRXRD) was used to assess the quality of 6H-SiC crystals grown by sublimation method. The results show the occurrence of low-angle grain boundaries (LB) is close relative to the inclination of the crystal interface. At the central faceted region with 0° inclination the crystal is of high structural perfection. However, at the region close to the facet with less than 5° inclination LB occurs slightly and at the region close to the peripheral polytype ring with more than 5° inclination LB defect occurs heavily. The density of LB can be drastically reduced by decreasing radial temperature gradient that determines the shape of the crystal growth interface.

关键词： low-angle grain boundaries sublimation 6H-SiC radial temperature gradient