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Preparation and properties of a new porous ceramic material used in clean energy field
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作者 Shuming Wang Xiaofang Zhang +6 位作者 Fenghua Kuang Jiangshan Li Yanxin Wang Ruiping Wang Yanru Wang Xin Lin Jianming Li 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第7期1255-1260,共6页
At high tem perature, the oxide redox reactions of ceria can split H2O and CO2 to produce H2 and CO, so porous ceria with high temperature resistance and high specific surface area has an important foreground in clean... At high tem perature, the oxide redox reactions of ceria can split H2O and CO2 to produce H2 and CO, so porous ceria with high temperature resistance and high specific surface area has an important foreground in clean energy applications. In this work, a reticulated porous ceria ceramic material with interconnected porous structure was prepared by the impregnation technique using organic polyurethane sponges as template. The influences of pretreated sponge, dipping time length, pore size and sintering temperature on the porosity and strength of the porous ceria ceramics were system atically studied. With the increasing sintering temperature, the glass phase occurred and led to an increase in strength, but an decrease in porosity. Eventually, we analyzed the relationships betw een porosity and strength of these porous materials, aiming to provide theoretical and practical references for its application in clean-energy field. 展开更多
关键词 POROUS CERAMICS POROUS CERIA IMPREGNATION Clean-energy
Impregnated Sulfur in Carbonized Nitrogen-containing Porous Organic Frameworks as Cathode with High Rate Performance and Long Cycle Life for Lithium-sulfur Batteries
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作者 DONG Yan BEN Teng 《高等学校化学研究:英文版》 SCIE CAS CSCD 2019年第4期654-661,共8页
The undesirable cycling performance caused by soluble poly sulfides shuttling between anode and cathode has been considered as the main challenge that has hindered its practical applications for lithium-sulfiir(Li-S) ... The undesirable cycling performance caused by soluble poly sulfides shuttling between anode and cathode has been considered as the main challenge that has hindered its practical applications for lithium-sulfiir(Li-S) batteries. To solve tliis issue effectively, a nitrogen-containing porous carbon, namely JUC-Z2-900,developed from a porous organic framework, namely JUC-Z2, bearing a high surface area(805 m^2/g),small pore size(0.5 mil) and nitrogen doping(2.15%, mass fraction), has been used as a host material for Li-S batteries. The micropores of JUC-Z2-900 can confine the smaller sulfur molecules S2-4, which can essentially alleviate the critical problem of poly sulfide dissolution.Furthermore, nitrogen-containing JUC-Z2-900 can promote chemical adsorption of sulfur. The above two factors can improve the electrochemical performance of Li-S batteries effectively. To compare the eftects of sulfur contents and melt-difiusion strategy in JUC-Z2-900/S composites, a series of JUC-Z2-900/S composites was synthesized and tlieir electrochemical perfbnnances were explored, indicating good rate performance and excellent cycling stability of the composites contributed by both appropriate mass percentage of sulfiir and its confinement in the micropores. 展开更多
关键词 Li-S battery Nitrogen-containing POROUS carbon POROUS organic framework
Laser additive manufacturing of Zn porous scaffolds;Shielding gas flow, surface quality and densification
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作者 Peng Wen Yu Qin +4 位作者 Yanzhe Chen Maximilian Voshage Lucas Jauer Reinhart Poprawe Johannes Henrich Schleifenbaum 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第2期368-376,共9页
Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and ... Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and CT scanning. Massive Zn evaporation during laser melting largely influenced the formation quality during LPBF of Zn metal. The metal vapor in processing chamber was blown off and suctioned out efficiently by an optimized gas circulation system. Numerical analysis was used to design and testify the performance of gas flow. The surface of scaffolds was covered with numerous particles in different sizes. Processing pores occurred near the outline contour of struts. The average grain size in width was8.5m, and the hardness was 43.8 HV. Chemical plus electrochemical polishing obtained uniform and smooth surface without processing pores, but the diameter of struts reduced to 250 αm from the design value 300 m. The poor surface quality and processing pores were resulted by the splashing particles included spatters and powders due to the recoil force of evaporation, and the horizontal movement of liquid metal due to overheating and wetting. The insufficient melting at the outline contour combined with good wetting of Zn liquid metal further increased the surface roughness and processing pores. 展开更多
关键词 ADDITIVE manufacturing Powder bed fusion LASER Porous SCAFFOLD ZN
166 dtex/288 f+44 dtex涤氨空包纱一步法生产工艺
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作者 张国平 沈建峰 +3 位作者 费东龙 王海英 费建丰 张小磊 《合成纤维》 CAS 2019年第7期15-16,52共3页
探讨了采用一体机一步法生产多孔166 dtex/288 f+44 dtex涤氨空包纱的主要工艺。结果表明:在一体机上生产时,涤纶的拉伸比选择1.62,上热箱温度控制在185℃,D/Y为1.70,氨纶的牵伸比为3.5,网络喷嘴采用1.6 mm带涡流腔椭圆孔,网络压力控制... 探讨了采用一体机一步法生产多孔166 dtex/288 f+44 dtex涤氨空包纱的主要工艺。结果表明:在一体机上生产时,涤纶的拉伸比选择1.62,上热箱温度控制在185℃,D/Y为1.70,氨纶的牵伸比为3.5,网络喷嘴采用1.6 mm带涡流腔椭圆孔,网络压力控制在0.3 MPa,机台速度为680 m/mim,可使多孔166 dtex/288 f+44 dtex涤氨空包纱生产过程稳定,产品品质可控,性能指标满足客户需求。 展开更多
关键词 涤氨空包纱 一步法 多孔 生产工艺
Adsorption of single and mixed haloacetonitriles on silica-based porous materials: Mechanisms and effects of porous structures
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作者 Panida Prarat Chawalit Ngamcharussrivichai +1 位作者 Sutha Khaodhiar Patiparn Punyapalakul 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第5期346-360,共15页
Adsorption mechanisms and the role of different porous and crystalline structures on the removal of five haloacetonitriles(HANs) over hexagonal mesoporous silica(HMS), titanium substituted mesoporous silica(Ti-HMS), r... Adsorption mechanisms and the role of different porous and crystalline structures on the removal of five haloacetonitriles(HANs) over hexagonal mesoporous silica(HMS), titanium substituted mesoporous silica(Ti-HMS), rod-shaped SBA-15 and microporous zeolite Na Y were investigated. In addition, the effect of p H on adsorption mechanism and selective adsorption of five HANs individually and in an equimolar mixed solution were evaluated.The results indicated that the intraparticle diffusion rate constants of the mesoporous adsorbents were higher than that of the microporous Na Y. In single solute, the order of adsorption preference(highest to lowest) was mono-HANs > di-HANs > tri-HAN. However,in mixed solute, the large molecular weight of the tri-HAN and di-HANs are more easily adsorbed than the smaller molecular weight mono-HANs. Except for SBA-15, the order of adsorption capacities in mixed HANs solute was not different compared to that observed for the single HAN solute, which might be caused by the higher accessibility to the active sites due to larger pore size. The ion-dipole electrostatic interaction was likely to be the main adsorption mechanism, and was favored at high p H values due to the high negative surface charge density of the adsorbent. The molecular structure of the HANs and hydrophilic/hydrophobic nature affected the adsorption capacities and their selective adsorption from mixed solutes. 展开更多
关键词 Haloacetonitrile ADSORPTION mechanism POROUS structure Ion-dipole ELECTROSTATIC interaction HYDROPHILICITY
Numerical Analysis on Thermal Function of Clothing with PCM Microcapsules 预览
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作者 LIU Wenyi LI Fengzhi LIU Weihua 《南京航空航天大学学报:英文版》 EI CSCD 2019年第2期320-329,共10页
To study the influences of phase change material(PCM)microcapsules in clothing on human thermal responses,a mathematical model is developed.The improved Stolwijk’s model is used to simulate human thermo-regulatory pr... To study the influences of phase change material(PCM)microcapsules in clothing on human thermal responses,a mathematical model is developed.The improved Stolwijk’s model is used to simulate human thermo-regulatory process,and the coupled heat and moisture transfer including the moisture sorption/desorption of fibers and effects of phase transition temperature range on the phase change processes of the PCM is considered in clothing model.Meanwhile,the theoretical predictions are validated by experimental data.Then,the interactions between human body thermal responses and the heat and moisture transfer in clothing are discussed by comparing the prediction results with PCMs and without PCMs.Also the effects of fiber hygroscopicity on clothing and human thermal responses are compared.The conclusion shows that the clothing with PCMs microcapsules can delay the human temperature variations and decrease the sweat accumulation rate on the skin surface and heat loss during changing of ambient conditions,and fiber hygroscopicity reduces the effect of PCM microcapsules on delaying garment temperature variations very significantly. 展开更多
关键词 PCM MICROCAPSULE porous textiles heat and MOISTURE transfer numerical simulation human thermoregulatory model
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Preparation of Polysulfonamide Porous Paper and Its Adsorption Properties 预览
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作者 Sufeng Zhang Nan Zhang +1 位作者 Liwei Qian Min Du 《造纸与生物质材料:英文版》 2019年第3期23-29,共7页
Three-dimensional porous paper was prepared by using polysulfonamide (PSA) fiber and pulp as the raw materials. The effect of PSA fiber to pulp ratios on the mechanical strength and adsorption properties (using methyl... Three-dimensional porous paper was prepared by using polysulfonamide (PSA) fiber and pulp as the raw materials. The effect of PSA fiber to pulp ratios on the mechanical strength and adsorption properties (using methyl orange and rhodamine B dyes in their aqueous phase) of the paper were studied. The results showed that the tensile strength and elongation characteristics decreased as the PSA fiber to pulp ratio increased, while the tear strength increased. PSA paper showed good adsorption performance for both methyl orange and rhodamine B, with the adsorption process conforming to the pseudo-second-order and Langmuir isotherm models, indicating monolayer chemical adsorption. The study has provided an improved theoretical and scientific basis for the further development and application of PSA paper. 展开更多
关键词 POLYSULFONAMIDE PAPER mechanical STRENGTH ADSORPTION PROPERTY POROUS
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Flexible,Porous,and Metal–Heteroatom?Doped Carbon Nanofibers as Efficient ORR Electrocatalysts for Zn–Air Battery
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作者 Qijian Niu Binling Chen +3 位作者 Junxia Guo Jun Nie Xindong Guo Guiping Ma 《纳微快报:英文版》 CAS CSCD 2019年第1期147-163,共17页
Developing an e cient and durable oxygen reduction electrocatalyst is critical for clean-energy technology, such as fuel cells and metal–air batteries. In this study, we developed a facile strategy for the preparatio... Developing an e cient and durable oxygen reduction electrocatalyst is critical for clean-energy technology, such as fuel cells and metal–air batteries. In this study, we developed a facile strategy for the preparation of flexible, porous, and well-dispersed metal–heteroatom-doped carbon nanofibers by direct carbonization of electrospun Zn/Co-ZIFs/PAN nanofibers(Zn/Co-ZIFs/PAN). The obtained Zn/Co and N co-doped porous carbon nanofibers carbonized at 800 °C(Zn/Co–N@PCNFs-800) presented a good flexibility, a continuous porous structure, and a superior oxygen reduction reaction(ORR) catalytic activity to that of commercial 20 wt% Pt/C, in terms of its onset potential(0.98 V vs. RHE), half-wave potential(0.89 V vs. RHE), and limiting current density(-5.26 mA cm-2). In addition, we tested the suitability and durability of Zn/Co–N@PCNFs-800 as the oxygen cathode for a rechargeable Zn–air battery. The prepared Zn–air batteries exhibited a higher power density(83.5 mW cm-2), a higher specific capacity(640.3 mAh g-1), an excellent reversibility, and a better cycling life than the commercial 20 wt% Pt/C + RuO2 catalysts. This design strategy of flexible porous non-precious metal-doped ORR electrocatalysts obtained from electrospun ZIFs/polymer nanofibers could be extended to fabricate other novel, stable, and easy-to-use multi-functional electrocatalysts for clean-energy technology. 展开更多
关键词 Electrospinning Zn/Co-ZIFs Carbon nanofibers FLEXIBLE POROUS structure ORR Zn–air battery
Efficient catalytic hydrogen generation by intermetallic platinum-lead nanostructures with highly tunable porous feature
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作者 Bin E Lingzheng Bu +2 位作者 Qi Shao Yujing Li Xiaoqing Huang 《科学通报:英文版》 SCIE EI CSCD 2019年第1期36-43,共8页
The water-gas shift (WGS)reaction is an essential industrial reaction for upgrading hydrogen (H2)by removing carbon monoxide (CO),while highly efficient platinum (Pt)-based catalysts for WGS with simultaneously high a... The water-gas shift (WGS)reaction is an essential industrial reaction for upgrading hydrogen (H2)by removing carbon monoxide (CO),while highly efficient platinum (Pt)-based catalysts for WGS with simultaneously high activity and stability are still yet to be developed due to the poisoning issue during the reaction.Herein,we report on the porous PtPb peanut nanocrystals (porous PtPb PNCs)and porous PtPb octahedron nanocrystals (porous PtPb ONCs)with controllable ratios of Pt/Pb as extremely active and stable catalysts towards WGS reaction.It exhibits the composition-dependent activity with porous PtPb PNCs-40/ZnO being the most active for WGS to H2,16.9 times higher than that of the commercial Pt/C.The porous PtPb PNCs-40/ZnO also display outstanding durability with barely activity decay and negligible structure and composition changes after ten successive reaction cycles.X-ray photoelectron spectroscopy (XPS)results reveal that the suitable binding energy of Pt 4f7/12 and the high ratio of Pt(0) to Pt(Ⅱ)in porous PtPb PNCs/Zn0 and porous PtPb ONCs/ZnO are crucial for the enhanced WGS activity. The CO stripping results indicate the optimized CO adsorption strength on the Pt surface ensure the excellent WGS activity and the outstanding durability.The present work demonstrates an important advance in tuning the porous metal nanomaterials as highly efficient and durable catalysts for catalysis, energy conversion and beyond. 展开更多
关键词 POROUS Selective ETCHING Hydrogen Pt-Pb Water-gas shift
声频工程中空间吸声体特性及应用 预览
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作者 丁雷 《电声技术》 2019年第6期1-4,共4页
空间吸声体是一种用途广泛的吸声结构,具有非常高的吸声性能。对空间吸声体的形式与构造进行了详细论述,阐述了空间吸声体的吸声性能,分析影响空间吸声体吸声性能的最主要因素,对其应用场合及特点作了说明。
关键词 声频工程 多孔 吸声体 材料 构造
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Fluorescence spectra of colloidal self-assembled CdSe nano-wire on substrate of porous Al2O3/Au nanoparticles
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作者 张欣 邵丽萍 +3 位作者 彭嫚 白忠臣 张正平 秦水介 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期429-432,共4页
We present a self-assembly method to prepare array nano-wires of colloidal CdSe quantum dots on a substrate of porous Al2 O3 film modified by gold nanoparticles. The photoluminescence(PL) spectra of nanowires are in s... We present a self-assembly method to prepare array nano-wires of colloidal CdSe quantum dots on a substrate of porous Al2 O3 film modified by gold nanoparticles. The photoluminescence(PL) spectra of nanowires are in situ measured by using a scanning near-field optical microscopy(SNOM) probe tip with 100-nm aperture on the scanning near-field optical microscope. The results show that the binding sites from the edge of porous Al2 O3 nanopores are combined with the carboxyl of CdSe quantum dots’ surface to form an array of CdSe nanowires in the process of losing background solvent because of the gold nanoparticles filling the nano-holes of porous Al2 O3 film. Compared with the area of nonself-assembled nano-wire, the fluorescence on the Al2 O3/Au/CdSe interface is significantly enhanced in the self-assembly nano-wire regions due to the electron transfer conductor effect of the gold nanoparticles’ surface. In addition, its full width at half maximum(FWHM) is also obviously widened. The method of enhancing fluorescence and energy transfer can widely be applied to photodetector, photocatalysis, optical display, optical sensing, and biomedical imaging, and so on. 展开更多
关键词 enhanced PHOTOLUMINESCENCE Cd Se NANO-WIRE COLLOIDAL SELF-ASSEMBLED method porous Al2O3 film
One-step preparation of polyimide-inlaid amine-rich porous organic block copolymer for efficient removal of chlorophenols from aqueous solution
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作者 Yanyang Liu Haijian Ou +4 位作者 Shangqing Li Qingliang You Huixian Liu Guiying Liao Dongsheng Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期215-229,共15页
A novel polyimide-inlaid amine-rich porous organic block copolymer(PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine(MA)/terephthalaldehyde(TA)/pyromellitic dianhydride(P... A novel polyimide-inlaid amine-rich porous organic block copolymer(PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine(MA)/terephthalaldehyde(TA)/pyromellitic dianhydride(PMDA), at molar ratios of 4/3/1, 4/2/2 and 4/1/3. The copolymer contained both aminal groups belonging to ARPOP and imide groups belonging to PI, and the bonding styles of the monomers and growth orientations of the polymeric chains were diversiform, forming an excellent porous structure. Notably, MA/TA/PMDA(4/2/2) had a surface area and pore volume of 487.27 m~2/g and 1.169 cm~3/g,respectively. The adsorption performance of the materials towards 2,4-dichlorophenol(2,4-DCP) in ultra-pure water was systematically studied. The pH value of 7 was optimal in aqueous solution. Na~+ and Cl~-ions did not negatively affect the adsorption process, while humic acid(HA) slightly decreased the capacity. The equilibrium time was 40 sec, and the maximum adsorption capacity reached 282.49 mg/g at 298 K. The removal process was endothermic and spontaneous, and the copolymer could maintain its porous structure and consistent performance after regeneration by treatment with alkali. Moreover, to further assess the practical applicability of the material, the adsorption performance towards 2,4-DCP in river water was also investigated. This paper demonstrated that the PI-b-ARPOP can be an efficient and practical adsorbent to remove chlorophenols from aqueous solution. 展开更多
关键词 POROUS block copolymer SCHIFF base POLYIMIDE Adsorption 2 4-DICHLOROPHENOL
Facile oxalic acid-assisted construction of laminated porous N-deficient graphitic carbon nit ride: Highly efficient visible-light-driven hydrogen evolution photocatalyst 预览
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作者 Fengli Yang Jia Ren +3 位作者 Qianqian Liu Lu Zhang Yuanyuan Chai Wei-Lin Dai 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第6期1-8,共8页
The laminated porous N-deficient g-C3N4(CN–H)is successfully synthesized by a facile two-step hydrothermal calcination method using oxalic acid-assisted melamine as the precursor.Compared with pristine g-C3N4(224μmo... The laminated porous N-deficient g-C3N4(CN–H)is successfully synthesized by a facile two-step hydrothermal calcination method using oxalic acid-assisted melamine as the precursor.Compared with pristine g-C3N4(224μmol g-1h-1),the CN–H shows superior photocatalytic hydrogen production activity(up to 728μmol g-1h-1),which is three times higher than the unmodified counterpart.To draw out the multifaceted influences of oxalic acid modification on the visible-light-induced photocatalytic activity,various techniques are utilized to investigate the formation mechanism,structural characteristics and photoelectrical properties of CN–H.The results indicate that the addition of a trace amount of oxalic acid to the precursor melamine results in a g-C3N4 structure possessing the advantage of both nitrogen defects and laminated porosity.These properties can enlarge specific surface areas of g-C3N4,enhance an efficient separating of photogenerated electron-hole pairs and extend the range of spectral response,all contributing to the enhancement of the visible-light-induced photocatalytic activity. 展开更多
关键词 Oxalic acid MELAMINE LAMINATED POROUS N-deficient g-C3N4 Visible-light-induced photocatalytic activity for H2 generation
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Design and Simulation of Flow Field for Bone Tissue Engineering Sca old Based on Triply Periodic Minimal Surface
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作者 Zhen Wang Chuanzhen Huang +3 位作者 Jun Wang Peng Wang Shisheng Bi Ch Asad Abbas 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期193-202,共10页
A novel method was proposed to design the structure of a bone tissue engineering scafold based on triply periodic minimal surface.In this method,reverse engineering software was used to reconstruct the surface from po... A novel method was proposed to design the structure of a bone tissue engineering scafold based on triply periodic minimal surface.In this method,reverse engineering software was used to reconstruct the surface from point cloud data.This method overcomes the limitations of commercially available software packages that prevent them from generating models with complex surfaces used for bone tissue engineering scafolds.Additionally,the fluid feld of the scafolds was simulated through a numerical method based on fnite volume and the cell proliferation performance was evaluated via an in vitro experiment.The cell proliferation and the mass flow evaluated in a bioreactor further verifed the flow feld simulated using computational fluid dynamics.The result of this study illustrates that the pressure value drops rapidly from 0.103 Pa to 0.011 Pa in the y-axis direction and the mass flow is unevenly distributed in the outlets.The mass flow in the side outlets is observed to be approximately 24.3 times higher thanthe bottom.Importantly,although the mean value of wall shear stress is signifcantly more than 0.05 Pa,there is stil a large area with a suitable shear stress below 0.05 Pa where most cells can proliferate well.The result shows that th inlet velocity 0.0075 m/s is suitable for cell proliferation in the scafold.This study provides an insight into the design analysis,and in vitro experiment of a bone tissue engineering scafold. 展开更多
关键词 BONE tissue ENGINEERING Porous SCA OLD Flow field REVERSE ENGINEERING Cell proliferation
粉末冶金多孔高氮奥氏体不锈钢的制备及性能
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作者 胡玲 李烈军 +3 位作者 彭翰林 倪东惠 陈松军 张伟鹏 《材料研究学报》 EI CAS CSCD 北大核心 2019年第5期345-351,共7页
采用粉末冶金方法制备了多孔高氮奥氏体不锈钢并研究其力学性能和耐腐蚀性能。结果表明,高温气固渗氮能促进双相不锈钢向奥氏体不锈钢的转变,在其显微组织中出现了细条状和颗粒状CrN相析出物。随着造孔剂含量的提高孔隙率随之提高,而力... 采用粉末冶金方法制备了多孔高氮奥氏体不锈钢并研究其力学性能和耐腐蚀性能。结果表明,高温气固渗氮能促进双相不锈钢向奥氏体不锈钢的转变,在其显微组织中出现了细条状和颗粒状CrN相析出物。随着造孔剂含量的提高孔隙率随之提高,而力学性能和耐腐蚀性能降低。与普通的多孔不锈钢相比,这种多孔高氮奥氏体不锈钢的力学性能更加优越,源于N的固溶强化和CrN等析出物的强化机制。随着孔隙率的提高多孔高氮奥氏体不锈钢的腐蚀倾向和腐蚀速率逐渐增大,造孔剂含量(质量分数)为10%的试样具有最佳的耐腐蚀性能。提高烧结温度有利于烧结块体的致密化,使腐蚀速率明显下降。 展开更多
关键词 金属材料 高氮奥氏体不锈钢 粉末冶金 多孔 力学性能 耐腐蚀性能
Stabilization of nanoscale zero-valent iron in water with mesoporous carbon(n ZVI@MC)
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作者 Junming Shi Jing Wang +2 位作者 Wei Wang Wei Teng Wei-xian Zhang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第7期28-33,共6页
Two challenges persist in the applications of nanoscale zero-valent iron(nZVI) for environmental remediation and waste treatment: limited mobility due to rapid aggregation and short lifespan in water due to quick oxid... Two challenges persist in the applications of nanoscale zero-valent iron(nZVI) for environmental remediation and waste treatment: limited mobility due to rapid aggregation and short lifespan in water due to quick oxidation. Herein, we report the nZVI incorporated into mesoporous carbon(MC) to enhance stability in aqueous solution and mobility in porous media. Meanwhile, the reactivity of nZVI is preserved thanks to high temperature treatment and confinement of carbon framework. Small-sized(~16 nm) nZVI nanoparticles are uniformly dispersed in the whole carbon frameworks. Importantly, the nanoparticles are partially trapped across the carbon walls with a portion exposed to the mesopore channels. This unique structure not only is conductive to hold the nZVI tightly to avoid aggregation during mobility but also provides accessible active sites for reactivity. This new type of nanomaterial contains ~10 wt% of iron. The nZVI@MC possesses a high surface area(~ 500 m~2/g) and uniform mesopores(~ 4.2 nm) for efficient pollutant diffusion and reactions. Also, high porosity of nZVI@MC contributes to the stability and mobility of nZVI. Laboratory column experiments further demonstrate that nZVI@MC suspension(~4 g Fe/L) can pass through sand columns much more efficiently than bare nZVI while the high reactivity of nZVI@MC is confirmed from reactions with Ni(II). It exhibits remarkably better performance in nickel(20 mg/L) extraction than mesoporous carbon, with 88.0% and 33.0%uptake in 5 min, respectively. 展开更多
关键词 MESOPOROUS carbon NANOSCALE zero-valent iron MOBILITY Porous media HEAVY metal removal
新型多孔加强桥梁伸缩缝结构设计及应用研究 预览
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作者 高炜党 《北方交通》 2019年第1期37-39,44共4页
桥梁伸缩缝是防止桥梁因水平和竖直方向变形而破坏的重要连接构件,车辆荷载和环境变化反复作用在伸缩缝上。伸缩缝是桥梁结构中脆弱易损的构件,伸缩缝的损害严重影响桥梁的使用功能和使用寿命。分析了现有桥梁伸缩缝的种类和使用效果,... 桥梁伸缩缝是防止桥梁因水平和竖直方向变形而破坏的重要连接构件,车辆荷载和环境变化反复作用在伸缩缝上。伸缩缝是桥梁结构中脆弱易损的构件,伸缩缝的损害严重影响桥梁的使用功能和使用寿命。分析了现有桥梁伸缩缝的种类和使用效果,针对现有伸缩缝的不足做出改进,设计出一种新型多孔加强桥梁伸缩缝,以解决现有的桥梁伸缩缝存在的抗冲击性能差且容易渗水及被杂物堵塞的技术问题。 展开更多
关键词 桥梁 伸缩缝 多孔 加强
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Methane hydrate formation and dissociation behaviors in montmorillonite
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作者 Kefeng Yan Xiaosen Li +3 位作者 Zhaoyang Chen Yu Zhang Chungang Xu Zhiming Xia 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第5期1212-1218,共7页
The methane hydrate formation and the methane hydrate dissociation behaviors in montmorillonite are experimentally studied. Through the analyses of the microstructure characteristic, the study obtains the porous chara... The methane hydrate formation and the methane hydrate dissociation behaviors in montmorillonite are experimentally studied. Through the analyses of the microstructure characteristic, the study obtains the porous characteristic of montmorillonite. It is indicated that methane hydrate in montmorillonite forms the structure I (si) crystal. Meanwhile, molecular dynamics simulation is carried out to study the processes of the methane hydrate formation and the methane hydrate dissociation in montmorillonite. The microstructure and microscopic properties are analyzed. The methane hydrate formation and methane hydrate dissociation mechanisms in the montmorillonite nanopore and on the montmorillonite surface are expounded. Combining the experimental and simulating analyses, the results indicate the methane hydrate formation and methane hydrate dissociation processes have little influence upon the crystal structure of porous media from either micro- or macro-analysis. It is beneficial to the fundamental researches on the exploitation and security control technologies of natural gas hydrate in deep-sea sediments. 展开更多
关键词 METHANE HYDRATE POROUS media Formation/dissociation behavior Molecular dynamics simulation
Experimental investigating on the reflected waves from the caisson-type vertical porous seawalls 预览
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作者 Mehdi Esmaeili Maryam Rahbani Ali Karami Khaniki 《海洋学报:英文版》 SCIE CAS CSCD 2019年第6期117-123,共7页
The hydrodynamic efficiencies of caisson-type vertical porous seawalls used for protecting coastal areas were calculated in this study. Physical models were developed to compare the wave reflection from vertical plane... The hydrodynamic efficiencies of caisson-type vertical porous seawalls used for protecting coastal areas were calculated in this study. Physical models were developed to compare the wave reflection from vertical plane, semi-porous, and porous seawalls caused by both regular and random waves. Tests were carried out for a wide range of wave heights, wave periods, and different water depths (d=0.165, 0.270 and 0.375 m). The performance regarding the reflected waves from porous and semi-porous seawalls showed improvement when compared with those from the plane seawall. The reflection coefficients of the porous and semi-porous seawalls were calculated as 0.6 and 0.75, respectively, while the coefficient for the fully reflecting plane vertical wall was significantly higher (0.9). It was also observed that the reflection coefficient decreases with increase in wave steepness and relative water depth. In addition, the reduction in the reflection coefficient of porous and semi-porous seawalls, as compared to that of a plane seawall, was observed for both regular and random waves. New equations were also proposed to calculate the reflection coefficient of different types of seawalls with the aid of laboratory experiments. By verifying the developed equations using some other experimental data, it was validated that the equations could be used for practical situations. The results of the present study can be applied to optimize the design of vertical seawalls and for coastal protecting schemes. 展开更多
关键词 reflection coefficient POROUS SEAWALL regular WAVE random WAVE FLUME
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Humidity-responsive Bilayer Actuators Comprised of Porous and Nonporous Poly(acrylic acid)/Poly(allylamine hydrochloride) Films
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作者 Miao Zheng Tang-Jie Long +1 位作者 Xiao-Ling Chen Jun-Qi Sun 《高分子科学:英文版》 SCIE CAS CSCD 2019年第1期52-58,共7页
Bilayer humidity-responsive actuators are generally composed of actuating and supporting layers of different materials with largely different wettability.Such kinds of bilayer actuators suffer from low adhesive force ... Bilayer humidity-responsive actuators are generally composed of actuating and supporting layers of different materials with largely different wettability.Such kinds of bilayer actuators suffer from low adhesive force between the two layers during usage.This study demonstrates the preparation of humidity-responsive bilayer actuators that have the same materials in the actuating and supporting layers to avoid the adhesive issue.The bilayer actuators consist of a porous poly(acrylic acid)(PAA)/poly(allylamine hydrochloride)(PAH)layer and a nonporous PAA/PAH layer that are fabricated by exponentially layer-by-layer assembly method.At a high/low relative humidity(RH),the nonporous PAA/PAH layer can efficiently expand/shrink by absorbing/desorbing water while the volume expansion/shrinkage of the porous PAA/PAH layer in an environment with changed humidity is significantly suppressed by the micrometer-sized pores.The largely different expansion/shrinkage of the nonporous and porous PAA/PAH layers when subjected to humidity changes enables rapid and reversible rolling/unrolling motions of the bilayer actuator.The bilayer actuator shows a faster rolling speed and a larger bending curvature when subjected to a larger humidity increase. 展开更多
关键词 Layer-by-layer assembly Materials science POROUS FILMS Surface chemistry
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