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On the formation of Basu’s Type Ⅲ(peeled orange) gunshot residues 预览
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作者 Felice Nunziata Matteo Donghi 《Defence Technology(防务技术)》 CAS CSCD 2019年第1期23-26,共4页
In a famous paper published in 1982,a very special class of gunshot residue particles(GSR)was named by Samarendra Basu“peeled orange”,due to their particular structure,consisting of a barium/antimony core covered by... In a famous paper published in 1982,a very special class of gunshot residue particles(GSR)was named by Samarendra Basu“peeled orange”,due to their particular structure,consisting of a barium/antimony core covered by an outer lead leaflet.In this class of GSR particles the surface may show nodular structures of lead.Basu proposed an explanation in terms of a nucleus of antimony and barium that captures lead vapours produced after the explosion of a cartridge into a firearm:as solidification points of antimony and barium are close one another,both higher than solidification point of lead,he stated that lead occurs as a layer around the core in peeled orange GSR particles.In this paper we study the thermodynamic of the barium/antimony alloy and we hypothesize a formation process in terms of colloidal metal growth,charged particles and electrostatic attraction.We propose an updated model of formation for peeled orange GSR particles that explains the existence of outer lead leaflet and nodules in terms of electrostatic attraction of lead nanoparticles and instability of lead droplets. 展开更多
关键词 Peeled ORANGE PARTICLES GSR CDR CHARGED PARTICLES Electrostatic ATTRACTION Rayleigh DROPLET stability
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Intermediate Energy Reactions Versus Heavy-Ion Fusion: Light Particle Emission and Post-Saddle Friction in the Presence of Deformation Effects
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作者 陈娜 叶巍 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第6期697-701,共5页
A decaying nucleus undergoes a change in deformation when it fissions. This affects the particle emission in the fission process. Using the dynamical Langevin model, we investigate the role of deformation in the sensi... A decaying nucleus undergoes a change in deformation when it fissions. This affects the particle emission in the fission process. Using the dynamical Langevin model, we investigate the role of deformation in the sensitivity of post-saddle neutrons and light charged particles(LCPs) to the post-saddle friction strength(β) for heavy nuclei240 Am produced with different initial conditions:(i) a low excitation energy E*and a large spin o(provided via a fusion mechanism) and(ii) a high E*and a large o as well as a higher E*but a small o(provided in peripheral and near-central intermediate energy heavy-ion reactions, respectively). It is shown that deformation obviously enhances the sensitivity of post-saddle neutrons to β at intermediate-energy peripheral collisions and that for case(i), the drop of LCPs emission due to deformation makes post-saddle LCPs to be almost insensitive to β, but for case(ii) LCPs still have a significant change with β. Furthermore, we find that post-saddle LCPs display a greater sensitivity to β for near-central collisions than for peripheral collisions. These results suggest that given the deformation effects, to better probe post-saddle dissipation properties with neutrons(LCPs) in experiments, it is best to choose those excited heavy nuclear systems populated in peripheral(near-central) collisions at intermediate energies. 展开更多
关键词 post-saddle FRICTION deformation EXCITATION ENERGY LIGHT particles stochastic model
3DPMD-Arc-based additive manufacturing with titanium powder as raw material 预览
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作者 Hoefer Kevin Mayr Peter 《中国焊接:英文版》 EI CAS 2019年第1期11-15,共5页
The study aims to demonstrate the suitability of the 3DPMD for the production of titanium components with and without reinforcing particles in layer-by-layer design. Various demonstrators are prepared and analyzed. Th... The study aims to demonstrate the suitability of the 3DPMD for the production of titanium components with and without reinforcing particles in layer-by-layer design. Various demonstrators are prepared and analyzed. The microstructure, the porosity and the hardness values of the different structures are compared with each other through metallographic cross-sections. The uniform distribution of the carbides and the interaction with the matrix was analyzed by SEM and EDX.The miller-test method (ASTM G75-07) was used to determine data for the relative abrasivity of the structures. In summary, 3DPMD offers the possibility to produce titanium structures with and without reinforced particles. Using automated routines, it is possible to generate metal structures using welding robots directly from the CAD drawings. Microstructures and properties are directly related to the process and therefore material-process-property relationships are discussed within this work. 展开更多
关键词 ADDITIVE MANUFACTURING PLASMA TITANIUM 3D PLASMA metal DEPOSITION reinforced PARTICLES
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Drawdown mechanism of light particles in baffled stirred tank for the KR desulphurization process
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作者 Meng Li Yangbo Tan +2 位作者 Jianglong Sun De Xie Zeng Liu 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期247-256,共10页
To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floati... To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floating particles in transformative Kanbara Reactor(KR) are measured in one and four baffled stirred tanks experimentally. Then numerical simulations with standard k-ε model coupled with volume of fluid model(VOF) and discrete phase model(DPM) are conducted to analyze the flow field at the just drawdown speed Njd. The torques on the impeller obtained from experiments and simulations agree well with each other, which indicates the validity of our numerical simulations. Based on the simulations, three main drawdown mechanisms for floating particles, the axial circulation, turbulent fluctuation and largescale eddies, are analyzed. It’s found that the axial circulation dominates the drawdown process at small submergence(S = 1/4 T and 1/3 T) and the large-scale eddies play a major role at large submergence(S= 2/3 T and 3/4 T). Besides, the turbulent fluctuation affects the drawdown process significantly for up pumping mode at small submergence(S = 1/4 T and 1/3 T) and for down pumping mode at large submergence(S= 2/3 T and 3/4 T). This paper helps to provide a more comprehensive understanding of the KR desulphurizer drawdown process in the baffled stirred tank. 展开更多
关键词 LIGHT PARTICLES DRAWDOWN MECHANISM Baffled stirred tank SUBMERGENCE Numerical simulations KR impeller
Particle contact angle at the oil-water interface: Effect of surface silanization
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作者 Keliang Wang Gang Wang Chunjing Lu 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第3期218-224,共7页
A novel and efficient method was developed to vary the particle contact angle (θ) at the wax-water interface by tailoring the degree of Υ-aminopropyltriethoxysilane (APTES) grafting onto silica particles.The three-p... A novel and efficient method was developed to vary the particle contact angle (θ) at the wax-water interface by tailoring the degree of Υ-aminopropyltriethoxysilane (APTES) grafting onto silica particles.The three-phase θ determines the degree of particle penetration into the respective phases.Increasing the APTES grafting density of the silica particles resulted in a three-phase θ increase from 22° to 70°.Furthermore,increasing APTES grafting density results in silica particles packing more closely and orderly on the surface of the wax colloidosomes.A series of fluorinated Janus particles were prepared by the subsequent surface chemical modification of the modified silica particles adsorbed on the wax surface.Silica particles with tailored APTES grafting densities can be utilized to tune the Janus balance during the synthesis of Janus particles based on Pickering emulsion methods. 展开更多
关键词 JANUS particles SURFACE MODIFICATION Aminopropyltriethoxysilane PICKERING emulsions Contact angle
水汽对膜法捕集CO2的影响 预览
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作者 杨林军 孙莹 +1 位作者 张琳 王霞 《高校化学工程学报》 EI CAS CSCD 北大核心 2019年第4期972-979,共8页
为了考察水汽单独存在及与SO2或颗粒物共存时对聚酰亚胺(PI)分离膜和聚丙烯(PP)吸收膜捕集CO2性能的影响规律,利用自行搭建的CO2膜捕集试验台进行了研究。结果表明:在试验条件下,当烟气的相对湿度达到90%时,PI分离膜对CO2/N2的分离因子... 为了考察水汽单独存在及与SO2或颗粒物共存时对聚酰亚胺(PI)分离膜和聚丙烯(PP)吸收膜捕集CO2性能的影响规律,利用自行搭建的CO2膜捕集试验台进行了研究。结果表明:在试验条件下,当烟气的相对湿度达到90%时,PI分离膜对CO2/N2的分离因子略有上升,但渗透速率下降,PP膜的CO2吸收效率下降7%,经N2反吹后,PI膜和PP膜的捕集效率均能得到恢复;水汽与SO2共存,PI分离膜的CO2/N2分离因子和渗透速率分别下降5.64%和24.54%,PP吸收膜脱除效率下降18%,但经N2反吹及膜丝实验前后红外测试表明水汽与SO2共存对PI膜和PP膜性能造成的影响都是可逆的;水汽与颗粒物共存时,PI分离膜的CO2/N2分离因子和渗透速率分别下降39.79%和49.82%,PP吸收膜脱除效率下降18.9%,通过N2反吹分析水汽和颗粒物共存对PI分离膜和PP膜造成的影响不可逆。 展开更多
关键词 CO2膜捕集 分离膜 吸收膜 水汽 SO2 颗粒物
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颗粒间距及相对运动对轴承油膜压力的影响 预览
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作者 韩海燕 李娜娜 尚雪梅 《机械与电子》 2019年第3期27-29,共3页
针对滑动轴承润滑中润滑油含有固体颗粒的情况,将格子-波兹曼方法(LBM)应用到润滑问题的求解中,得到润滑油中含有固体颗粒时的油膜压力分布。并通过分析计算得出了颗粒间距及颗粒相对运动对轴承润滑的影响规律,使得轴承润滑分析更符合... 针对滑动轴承润滑中润滑油含有固体颗粒的情况,将格子-波兹曼方法(LBM)应用到润滑问题的求解中,得到润滑油中含有固体颗粒时的油膜压力分布。并通过分析计算得出了颗粒间距及颗粒相对运动对轴承润滑的影响规律,使得轴承润滑分析更符合实际工况。 展开更多
关键词 颗粒 格子波兹曼 润滑 轴承
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城市道路交叉口处颗粒物空间分布规律 预览
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作者 于泉 梁锐 +1 位作者 郭增增 朱小飞 《北京工业大学学报》 CAS CSCD 北大核心 2019年第5期485-492,共8页
为了在宏观上掌握交叉口处颗粒物的分布规律,通过采集北京市多个交叉口处的颗粒物质量浓度,并进一步分析颗粒物质量浓度与交通特性之间的相关关系以及数据之间的拟合估计,建立交叉口处颗粒物的空间扩散模型,最终得出颗粒物在城市道路交... 为了在宏观上掌握交叉口处颗粒物的分布规律,通过采集北京市多个交叉口处的颗粒物质量浓度,并进一步分析颗粒物质量浓度与交通特性之间的相关关系以及数据之间的拟合估计,建立交叉口处颗粒物的空间扩散模型,最终得出颗粒物在城市道路交叉口处的分布规律,即:颗粒物质量浓度在交叉口处横向断面上的分布基本呈现中央较高,随后向两侧递减的趋势;颗粒物在交叉口处50m范围内纵断面上的扩散规律为越靠近交叉口停车线的点位颗粒物质量浓度越高,波动越大,且人行道上的纵向分布波动性高于机动车道的波动性;颗粒物PM2.5与颗粒物PM10规律一致. 展开更多
关键词 交叉口 颗粒物 空间分布 扩散模型
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Characterization of high-pressure die-cast hypereutectic Al-Si alloys based on microstructural distribution and fracture morphology
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作者 X.Y. Jiao J. Wang +6 位作者 C.F. Liu Z.P. Guo G.D. Tong S.L. Ma Y. Bi Y.F. Zhang S.M. Xiong 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第6期1099-1107,共9页
The fracture behavior of high-pressure die-cast hypereutectic(HPDC) Al-Si alloys was investigated using a high-resolution laboratory CT and synchrotron X-ray tomography with a particular focus on the influence of HPDC... The fracture behavior of high-pressure die-cast hypereutectic(HPDC) Al-Si alloys was investigated using a high-resolution laboratory CT and synchrotron X-ray tomography with a particular focus on the influence of HPDC microstructure. Results showed that microstructure of the alloy was mainly comprised of primary silicon particles(PSPs), Al dendrites, Cu-rich phases and pores. Most of the coarse PSPs, Cu-rich phases and pores were located in the center of the specimen. The rapid solidification of HPDC led to a heterogeneous microstructural feature. Elemental Cu was enriched in the frontiers of solid-liquid interface, causing the formation of large size dendritic arms. The pores were formed in the interdendrites which endured high stress intensity under high applied stress. Microcracks were originated from pores and further connected Cu-rich phases causing intergranular fracture. PSPs worked as obstacles causing piling-up dislocations in the phase interface. In the regions where large size of PSPs enriched in, PSPs ruptured rather than debonded from matrix, indicating transgranular fractures of PSPs. Microcracks originated around pores and PSPs tended to converge on the main cracks to decrease the energy required for crack propagation. 展开更多
关键词 HYPEREUTECTIC AL-SI alloy Primary silicon particles POROSITY Fracture morphology High pressure die CASTING
N-doped carbon shell encapsulated PtZn intermetallic nanopartides as highly efficient catalysts for fuel cells
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作者 Yakun Xue Huiqi Li +8 位作者 Xieweiyi Ye Shuangli Yang Zhiping Zheng Xiao Han Xibo Zhang Luning Chen Zhaoxiong Xie Qin Kuang Lansun Zheng 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第10期2490-2497,共8页
The high cost and poor durability of Pt nanoparticles(NPs)have always been great challenges to the commercialization of proton exchange membrane fuel cells(PEMFCs).Pt-based intermetallic NPs with a highly ordered stru... The high cost and poor durability of Pt nanoparticles(NPs)have always been great challenges to the commercialization of proton exchange membrane fuel cells(PEMFCs).Pt-based intermetallic NPs with a highly ordered structure are considered as promising catalysts for PEMFCs due to their high catalytic activity and stability.Here,we reported a facile method to synthesize N-doped carbon encapsulated PtZn intermetallic(PtZn@NC)NPs via the pyrolysis of Pt@Zn-based zeolitic imidazolate framework-8(Pt@ZIF-8)composites.The catalyst obtained at 800℃(10%-PtZn@NC-800)was found to exhibit a half-wave potential(Ev2)up to 0.912 V versus reversible hydrogen electrode(RHE)for the cathodic oxygen reduction reaction in an acidic medium,which shifted by 26 mV positively compared to the benchmark Pt/C catalyst.Besides,the mass activity and specific activity of 10%-PtZn@NC-800 at 0.9 V versus RHE were nearly 3 and 5 times as great as that of commercial Pt/C,respectively.It is worth noting that the PtZn@NC showed excel I e nt stability in oxyge n reducti on reacti on(ORR)with just 1 mV of the Ev2 loss after 5,000 cycles,which is superior to that of most reported PtM catalysts(especially those disordered solid solutions).Furthermore,such N-doped carb on shell encapsulated PtZn intermetallic NPs showed significa ntly enha need performances towards the anodic oxidation reaction of organic small molecules(such as methanol and formic acid).The synergistic effects of the N doped carbon encapsulation structure and intermetallic NPs are responsible for outstanding performances of the catalysts.This work provides us a new engineering strategy to acquire highly active and stable multifunctional catalysts for PEMFCs. 展开更多
关键词 intermetallic nano particles oxygen reducti on reaction N-DOPING metal-organic frameworks PYROLYSIS
Improved thermal conductivity and dielectric properties of flexible PMIA composites with modified micro-and nano-sized hexagonal boron nitride
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作者 Cuangyu DUAN Yan WANG +2 位作者 Junrong YU Jing ZHU Zuming HU 《材料科学前沿:英文版》 SCIE CSCD 2019年第1期64-76,共13页
A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting tec... A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting technique.The effects of modified hBN particles on microstructure,mechanical properties,dielectric properties and thermal conductivities of fabricated composites were investigated.The results indicate that modified hBN particles manifest good compatibility with the PMIA matrix.The Young's modulus and Theat-resistance index of PMIA-based composites are increased with increasing the mass fraction of hBN particles.Due to additional thermal conductive paths and networks formed by nano-sized hBN particles,the K-m/n-hBN-30 composite displays the thermal conductivity of 0.94 W·m^-1·K^-1 higher than that of the K-m-hBN-30 composite(0.86 W·m^-1·K^-1),and more than 4 times higher than that of neat PMIA.Moreover,the obtained PMIA-based composites also show low dielectric constant and ideal dielectric loss.Owing to the excellent comprehensive performance,hBN/PMIA composites present potential applications in the broad field of electronic materials. 展开更多
关键词 poly(m-phenylene isophthalamide)(PMIA) thermal CONDUCTIVITY hBN PARTICLES DIELECTRIC property
Antiferromagnetic element Mn modified PtCo truncated octahedral nanoparticles with enhanced activity and durability for direct methanol fuel cells
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作者 Qiqi Zhang Jialong Liu +7 位作者 Tianyu Xia Jie Qi Haochang Lyu Baoyuan Luo Rongming Wang Yizhong Guo Lihua Wang and Shouguo Wang 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第10期2520-2527,共8页
Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents th... Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performanee for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively. 展开更多
关键词 Mn-PtCo trun cated octahedral nano particles an tiferromag netic eleme nt magnetic properties electrocatalytic performa nee
Corrosion of New Zirconium Claddings in 500℃/10.3 MPa Steam:Effects of Alloying and Metallography
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作者 Jing-Jing Liao Zhong-Bo Yang +4 位作者 Shao-Yu Qiu Qian Peng Zheng-Cao Li Ming-Sheng Zhou Hong Liu 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第8期981-994,共14页
With the aim of improving corrosion resistance of rod cladding for in-service and accident conditions,six new zirconium alloys(named N1-N6)have been designed.The contents of Sn and Nb were optimized for better behavio... With the aim of improving corrosion resistance of rod cladding for in-service and accident conditions,six new zirconium alloys(named N1-N6)have been designed.The contents of Sn and Nb were optimized for better behavior at high-temperature pressurized water,and Fe,Cr,V,Cu or Mo elements were added to the alloys to adjust the corrosion behavioi\The current work focused on the rapid corrosion behavior in 500℃/10.3 MPa steam for up to 1960 h,aiming to test the corrosion resistance at high temperature.The structure of matrix and properties of second-phase particles(SPPs)were characterized to find the main differences among these alloys.All the six alloys exhibited better corrosion resistance than N36,and NI was shown to have the best performance.A careful analysis of the corrosion kinetics curves revealed that Cr was beneficial for severe condition.Elements Fe,Cr,V,Cu or Mo aggregated into SPPs with diiferent concentrations and structures.This was demonstrated to be the main reason for different corrosion resistance.Due to good processing control,all alloys had a uniform structure and a uniform distribution of SPPs.As for N4,N6 and N36,the existing of large-size SPPs(450 nm)might be a contributing factor of the relatively poor corrosion resistance. 展开更多
关键词 NEW ZIRCONIUM cladding CORROSION behavior ALLOYING elements METALLOGRAPHY Second-phase particles
Development of a rapid and sensitivity magnetic chemiluminescence immunoassay for DNA methyltransferase 1 in human serum
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作者 Sitian He Leiliang He +9 位作者 Beibei Liu Songcheng Yu Li'e Liu Yongmei Tian Jia Wang Lihua Ding Yilin Wang Lingbo Qu Fei Yu Yongjun Wu 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第5期1031-1034,共4页
DNA methyltransferase 1(DNMT1)is a useful biomarker for lung cancer in early clinical diagnosis.A rapid magnetic chemiluminescence immunoassay(MCLIA)for DNMT1 in human serum has been developed.Horseradish peroxidase(H... DNA methyltransferase 1(DNMT1)is a useful biomarker for lung cancer in early clinical diagnosis.A rapid magnetic chemiluminescence immunoassay(MCLIA)for DNMT1 in human serum has been developed.Horseradish peroxidase(HRP)-second-Ab was used to labeled polyclonal antibodies of anti-DNMT1.DNMT1 in sample integrates with specific immunomagnetic beads and can constitute a supersandwiched immunoreaction.In magnetic field,nonspecific materials can be separated.After luminescent substrate luminol-H2O2-BIP was added,the relative light unit(RLU)of HRP was detected and was discovered to be directly proportional to the content of DNMT1 in sample.The correlative variables involved in the MCLIA value were optimized and the methodological evaluation was carried out.After optimization,in the range of0.5–128 ng/mL,the linear regression equation was y=0.5014 x+1.769(x was logCDNMT1,y was relative luminescence units(RLU)/RLU0),and the limit of detection was 0.01 ng/mL.The RSD of intra-and interassays were 15.8%–16.9%and 14.3%–18.1%,respectively.The recovery was from 70.0%to 106.2%.Furthermore,paralleled with purchasable enzyme-linked immunosorbent assay(ELISA)kits,MCLEIA had lower detection limit,wider linear range and shorter detection time.Therefore,the MCLEIA established in this study could be used for the sensitive detection of DNMT1 in serum sample. 展开更多
关键词 DNA METHYLTRANSFERASE 1 BIOMARKER CHEMILUMINESCENCE IMMUNOASSAY MAGNETIC particles Human SERUM
Optically tunable fluorescent carbon nanoparticles and their application in fluorometric sensing of copper ions
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作者 Minhuan Lan Shaojing Zhao +5 位作者 Shuilin Wu Xiaofang Wei Yanzhao Fu Juanjuan Wu Pengfei Wang Wenjun Zhang 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第10期2576-2583,共8页
A series of carb on nano particles(CNPs)with emissi on wavele ngth ranging from 483 to 525 nm were prepared by hydrothermal treatme nt of poly-3-thiopheneacetic acid(PTA)and NaOH.The emission wavelength and surface ox... A series of carb on nano particles(CNPs)with emissi on wavele ngth ranging from 483 to 525 nm were prepared by hydrothermal treatme nt of poly-3-thiopheneacetic acid(PTA)and NaOH.The emission wavelength and surface oxidation degree of CNPs were shown to be controllable by simply adjusti ng NaOH concentration.These CNPs prese nted obvious fluoresce nee spectral response toward copper ions(Cu^2+)through static quenching caused synergistically by electron transfer and inner filter effect.The O-and S-containing groups on the surface of CNPs were dem on strated to be resp on sible for their outsta nding sensing performa nee.Based on that,a CN Ps-based ratiometric fluoresce nt probe for Cu^2+with a high fluoresce nee quenching rate constant of 1.4×10^5 L/mol and a short resp onse time(10 s)was developed.Their practical applications in detecting Cu^2+in pond water and living cells were also dem on strated. 展开更多
关键词 carbon nano particles tun able fluorometric copper ions
Stabilizing silica nan oparticles in high saline water by using polyvinylpyrrolidone for reduction of asphaltene precipitation damage under dynamic condition
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作者 Mohammad Reza Aghajanzadeh Mohammad Sharifi 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第5期1021-1029,共9页
In this study, the performance of stable nanofluid containing SiO2 nanoparticles dispersed and stabilized in high salinity brine for asphaltene inhibition in dynamic condition is evaluated. In the first stage of this ... In this study, the performance of stable nanofluid containing SiO2 nanoparticles dispersed and stabilized in high salinity brine for asphaltene inhibition in dynamic condition is evaluated. In the first stage of this work, the stability of silica nanoparticles in different range of water salinity(0–100000 mg·L-1) is investigated. Next, stable nanofluid containing highest salinity is selected as asphaltene inhibitor agent to inject into the damaged core sample. The estimated values of oil recovery for base case, after damage process and after inhibition of asphaltene precipitation using nanofluid are 51.6%, 36.1% and 46.7%, respectively. The results showed the reduction in core damage after using nanofluid. In addition, the relative permeability curves are plotted for the base case, after damage process and also after inhibition of asphaltene precipitation using nanofluid. Comparison of relative permeability curves shows, relative permeability of oil phase decreased after damage process as compared with the base case. But after using nanofluid the oil relative permeability curve has shifted to the right and effective permeability of oil phase has been improved. 展开更多
关键词 Formation DAMAGE Enhanced oil recovery SALINITY ASPHALTENE Core FLOODING Nano particles
微波法制备铜锌锡硫的研究进展 预览
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作者 沈韬 柴鲜花 +1 位作者 孙淑红 朱艳 《材料导报》 EI CAS CSCD 北大核心 2019年第13期2159-2166,共8页
尽管以铜铟镓硒(CIGS)和碲化镉(CdTe)为代表的第二代薄膜太阳能电池已成功实现商业化,截至目前,以CIGS为吸收层的电池的效率已经突破23%,但由于In元素稀缺,Cd元素有剧毒,限制了该电池的大规模生产。铜锌锡硫(Cu 2ZnSnS 4,CZTS)是一种直... 尽管以铜铟镓硒(CIGS)和碲化镉(CdTe)为代表的第二代薄膜太阳能电池已成功实现商业化,截至目前,以CIGS为吸收层的电池的效率已经突破23%,但由于In元素稀缺,Cd元素有剧毒,限制了该电池的大规模生产。铜锌锡硫(Cu 2ZnSnS 4,CZTS)是一种直接带隙半导体,因具有禁带宽度合适、光吸收系数高、组分无毒和储量丰富等优点,而成为目前太阳能电池中最具有潜力的吸收层材料之一。目前以CZTS为吸收层的太阳能电池的效率已突破12%,已接近于商业化的多晶硅太阳能电池的效率。目前,CZTS粉体的制备方法主要为以溶剂热法、一锅法和热注入法为代表的溶液法。由于这些方法需要昂贵的仪器设备、复杂的操作顺序、较长的反应时间,且易产生杂相,严重制约着生产效率的提高。微波法也是一种溶液化学反应法,由于具有反应速度快、操作简单、效率高、加热均匀、能够减小热梯度等优势,近年在太阳能电池材料制备领域引起了广泛关注。微波法制备CZTS薄膜通常有一步成膜和两步成膜两种途径。两步成膜法先通过微波合成CTZS的粉体,再将粉体分散之后通过旋涂等方法获得CZTS的薄膜。采用这种方法得到的薄膜更加均匀、致密、稳定。然而,CZTS属于四元化合物,化学计量比的少量偏离就很容易产生其他杂相,因此如何减少和控制杂相的生成,制备纯相、形貌可控的CZTS纳米晶体并将其应用于薄膜太阳能电池显得至关重要。最近几年,除了研究CZTS对器件性能的影响外,研究者们主要从选择合适的有机溶剂、原料配比、反应时间、反应温度及表面活性剂等制备工艺方面不断尝试,并取得了丰硕的成果,在充分发挥微波法反应速度快、操作简单、效率高、加热均匀优势的同时大幅提升了器件效率。目前,以微波法合成的CZTS为吸收层材料制备的太阳能电池的转换效率已从最初的0.25%� 展开更多
关键词 微波 Cu2ZnSnS4 粉体 薄膜
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Ionic Liquid-Polypyrrole-Gold Composites as Enhanced Enzyme Immobilization Platforms forHydrogen Peroxide Sensing 预览
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作者 Meng Li Jing Wu +3 位作者 Haiping Su Yazhuo Shang Yifan He Honglai Liu 《北京日化》 2019年第2期15-32,共18页
In this work, three different aqueous solutions containing imidazole-based ILs w让h different alkyl chain lengths ([Cnmim]Br, n = 2Z 6,12) were adopted as the medium for the synthesis of ionic liquid-polypyrrole (IL-P... In this work, three different aqueous solutions containing imidazole-based ILs w让h different alkyl chain lengths ([Cnmim]Br, n = 2Z 6,12) were adopted as the medium for the synthesis of ionic liquid-polypyrrole (IL-PPy) composites. Herein, the ILs undertook the roles of the pyrrole solvent, the media for emulsion polymerization of PPy and PPy dopants, respectively. The electrochemical performances of the three IL-PPy composites on a glassy carbon electrode (GCE) were investigated by electrochemical experiments, which indicated that [Ci2mim]Br-PPy (Ci2~PPy) composites displayed better electrochemical performance due to their larger surface area and firmer immobilization on the GCE. Further, Ci2?PPy/GCE were decorated with Au microparticles by electrodeposition that can not only increase the conductivity, but also immobilize sufficient biomolecules on the electrode. Then, the obtained Ci2~PPy~Au/GCE with outstanding electrochemical performance was employed as a horseradish peroxidase (HRP) immobilization platform to fabricate a novel Ci2-PPy-Au-HRP/GCE biosensor for H2O2 detection. The results showed that the prepared Ci2-PPy-Au-HRP/GCE biosensor exhibited high sensitivity, fast response, and a wide detection range as well as low detection limit towards H2O2. This work not only provides an outstanding biomolecule immobilization matrix for the fabrication of highly sensitive biosensors, but also advances the understanding of the roles of ILs in improving the electrochemical performance of biosensors. 展开更多
关键词 ionic liquids (ILs) POLYPYRROLE (PPy) GOLD particles HORSERADISH PEROXIDASE (HRP) enzyme immobilization hydrogen PEROXIDE sensor
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钛柱撑蒙脱石颗粒的制备及其对镉离子的吸附 预览
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作者 宋祥 庹必阳 +2 位作者 赵徐霞 陈兵兵 龙文江 《功能材料》 EI CAS CSCD 北大核心 2019年第5期5099-5105,共7页
为脱除废水中镉离子,以钠基蒙脱石作基质材料,钛酸四丁酯为钛源,制备了钛柱撑蒙脱石。然后将聚乙烯醇、海藻酸钠、钛柱撑蒙脱石以一定的质量比制备钛柱撑蒙脱石颗粒,并进行颗粒的散失实验及镉离子的吸附实验,同时进行吸附等温线及吸附... 为脱除废水中镉离子,以钠基蒙脱石作基质材料,钛酸四丁酯为钛源,制备了钛柱撑蒙脱石。然后将聚乙烯醇、海藻酸钠、钛柱撑蒙脱石以一定的质量比制备钛柱撑蒙脱石颗粒,并进行颗粒的散失实验及镉离子的吸附实验,同时进行吸附等温线及吸附动力学研究。结果表明,Ti-MMT具有较大的晶面间距(d001=3.43nm)。当m(聚乙烯醇)∶m(海藻酸钠)∶m(钛柱撑蒙脱石)=0.6∶1.0∶20.0时,投加0.25g颗粒于pH值=6的100mg/L的镉离子废水中,在40℃下,吸附120min,颗粒对Cd^2+的吸附量达到7.89mg/g,去除率达到98.63%,且颗粒对Cd2+的吸附符合Langmuir等温线模型,吸附动力学符合拟二级动力学方程。 展开更多
关键词 钛柱撑蒙脱石 颗粒 吸附 镉离子
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Investigation of ion fishbone stability on HL-2A using NIMROD
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作者 杨耀荣 候雅巍 +6 位作者 陈伟 朱平 王先驱 邹志慧 余羿 许敏 叶民友 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第8期18-26,共9页
Numerical calculations of resistive internal kink mode with effects of energetic particles(EPs) on HL-2A have been performed using the hybrid kinetic-MHD model inplemented in the NIMROD code.The m/n=1/1 resistive inte... Numerical calculations of resistive internal kink mode with effects of energetic particles(EPs) on HL-2A have been performed using the hybrid kinetic-MHD model inplemented in the NIMROD code.The m/n=1/1 resistive internal kink mode is unstable in MHD limit.However, with kinetic effects of energetic ions, a fishbone mode is excited with mode frequency around 10 kHz.We calculate the impact of resistivity on the growth rate and frequency of ion fishbone mode,and the results are in good agreement with the analytic solutions, which are obtained by solving the fishbone dispertion relation including resistivity effect.The effects of βfracand cut off velocity of EP on fishbone mode are calculated in detail, where βfracis the ratio of EP pressure to background plasma pressure.This work presents a clear explanation of the stabilizing effect of ECRH on ion fishbone, which is first observed on HL-2A. 展开更多
关键词 ENERGETIC PARTICLES FISHBONE MODE hybrid simulation
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