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Design and Manufacturing Strategies for Fused Deposition Modelling in Additive Manufacturing:A Review
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作者 Hugo I.Medellin-Castillo Jorge Zaragoza-Siqueiros 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第3期1-16,共16页
Although several research works in the literature have focused on studying the capabilities of additive manufacturing(AM) systems, few works have addressed the development of Design for Additive Manufacturing(DfAM) kn... Although several research works in the literature have focused on studying the capabilities of additive manufacturing(AM) systems, few works have addressed the development of Design for Additive Manufacturing(DfAM) knowledge,tools, rules, and methodologies, which has limited the penetration and impact of AM in industry. In this paper a comprehensive review of design and manufacturing strategies for Fused Deposition Modelling(FDM) is presented.Consequently, several DfAM strategies are proposed and analysed based on existing research works and the operation principles, materials, capabilities and limitations of the FDM process. These strategies have been divided into four main groups: geometry, quality, materials and sustainability. The implementation and practicality of the proposed DfAM is illustrated by three case studies. The new proposed DfAM strategies are intended to assist designers and manufacturers when making decisions to satisfy functional needs, while ensuring manufacturability in FDM systems.Moreover, many of these strategies can be applied or extended to other AM processes besides FDM. 展开更多
关键词 ADDITIVE manufacturing(AM) DESIGN for ADDITIVE manufacturing(DfAM) FUSED Deposition Modelling(FDM) DESIGN and MANUFACTURING STRATEGIES
Grain boundary and microstructure engineering of Inconel 690 cladding on stainless-steel 316L using electron-beam powder bed fusion additive manufacturing
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作者 I.A. Segura L.E. Murr +7 位作者 C.A. Terrazas D. Bermudez J. Mireles V.S.V. Injeti K. Li B. Yu R.D.K.Misra R.B. Wicker 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第2期351-367,共17页
This research explores the prospect of fabricating a face-centered cubic(fcc) Ni-base alloy cladding(Inconel 690) on an fcc Fe-base alloy(316 L stainless-steel) having improved mechanical properties and reduced sensit... This research explores the prospect of fabricating a face-centered cubic(fcc) Ni-base alloy cladding(Inconel 690) on an fcc Fe-base alloy(316 L stainless-steel) having improved mechanical properties and reduced sensitivity to corrosion through grain boundary and microstructure engineering concepts enabled by additive manufacturing(AM) utilizing electron-beam powder bed fusion(EPBF). The unique solidification and associated constitutional supercooling phenomena characteristic of EPBF promotes[100] textured and extended columnar grains having lower energy grain boundaries as opposed to random, high-angle grain boundaries, but no coherent {111} twin boundaries characteristic of conventional thermo-mechanically processed fcc metals and alloys, including Inconel 690 and 316 L stainless-steel.In addition to [100] textured grains, columnar grains were produced by EPBF fabrication of Inconel 690 claddings on 316 L stainless-steel substrates. Also, irregular 2–3 μm diameter, low energy subgrains were formed along with dislocation densities varying from 108 to 109 cm2, and a homogeneous distribution of Cr23C6 precipitates. Precipitates were formed within the grains(with 3 μm interparticle spacing),but not in the subgrain or columnar grain boundaries. These inclusive, hierarchical microstructures produced a tensile yield strength of 0.527 GPa, elongation of 21%, and Vickers microindentation hardness of 2.33 GPa for the Inconel 690 cladding in contrast to a tensile yield strength of 0.327 GPa, elongation of 53%, and Vickers microindentation hardness of 1.78 GPa, respectively for the wrought 316 L stainlesssteel substrate. Aging of both the Inconel 690 cladding and the 316 L stainless-steel substrate at 685?C for50 h precipitated Cr23C6 carbides in the Inconel 690 columnar grain boundaries, but not in the low-angle(and low energy) subgrain boundaries. In contrast, Cr23C6 carbides precipitated in the 316 L stainless-steel grain boundaries, but not in the low energy coherent {111} twin boundaries. Consequently, the Inconel6 展开更多
关键词 Additive manufacturing ELECTRON-BEAM powder bed FUSION (EPBF) INCONEL 690 CLADDING 316L stainless steel Grain boundary engineering Materials characterization Mechanical properties
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
Tween 80浊点的测定及其影响因素
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作者 吴红艳 张德聪 于晓丹 《食品工业》 CAS 北大核心 2019年第3期184-186,共3页
测定非离子表面活性剂Tween 80的浊点,研究无机盐、醇、pH等对非离子表面活性剂Tween 80浊点的影响。试验结果表明,具有盐析性的无机盐的溶水能力大于胶束溶水能力,这使非离子表面活性剂析出,导致非离子表面活性剂的浊点降低;阴离子大... 测定非离子表面活性剂Tween 80的浊点,研究无机盐、醇、pH等对非离子表面活性剂Tween 80浊点的影响。试验结果表明,具有盐析性的无机盐的溶水能力大于胶束溶水能力,这使非离子表面活性剂析出,导致非离子表面活性剂的浊点降低;阴离子大于阳离子对浊点的影响,硫酸根>氯离子>硝酸根;有机醇中甲醇、乙醇略微升高浊点温度,而异丙醇则明显降低浊点温度;随着pH升高, Tween 80浊点温度随之降低。 展开更多
关键词 失水山梨醇单油酸酯聚氧乙烯醚(Tween 80) 非离子表面活性剂 浊点 缓冲溶液
Effects of Replacing Maize Silage with Silage Sweet Sorghum on Milk Production and Blood Biochemical Indexes of Dairy Cows 预览
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作者 Siwei WANG Kuiying LI +2 位作者 Shaoqing SHI Feng ZHANG Kun WANG 《农业生物技术:英文版》 CAS 2019年第3期87-91,共5页
In order to study the effects of replacing different proportions of silage maize with silage sweet sorghum treated by different fermentation methods on the production performance and blood biochemical indexes of dairy... In order to study the effects of replacing different proportions of silage maize with silage sweet sorghum treated by different fermentation methods on the production performance and blood biochemical indexes of dairy cows,25 Chinese Holstein lactating cows were randomly divided into 5 groups,5 in each group.The control check (CK) was fed the basal diet;for the experimental group 1 and the experimental group 2,50% of the silage maize in the basal diet was replaced with the additive silage sweet sorghum and the conventional silage sweet sorghum,respectively;and as to the experimental group 3 and the experimental group 4,all the silage maize in the basal diet was replaced with additive silage sweet sorghum and conventional silage sweet sorghum,respectively.The preliminary trial period was 7 d,and the trial period was 35 d.The results showed that the experimental group 1 and the experimental group 3 had the dry matter intake significantly higher than that of the experimental group 2,the experimental group 4 and the CK ( P <0.05).The daily milk yields of the experimental group 1 and the experimental group 2 were significantly lower than that of the CK ( P <0.05),and the experimental group 3 and the experimental group 4 were significantly lower than the experimental group 1 and the experimental group 2 ( P <0.05).The milk protein percentage of the experimental group 2 was extremely significantly higher than that of the experimental group 4 ( P <0.01).The experimental group 1,the experimental group 2 and the experimental group 3 showed the blood glucose levels extremely significantly higher than that in the CK ( P <0.01).The blood urea nitrogen contents in the experimental group 2 and the experimental group 4 were significantly higher than those in the experimental group 1 and the CK ( P <0.01).There were no significant differences in other blood biochemical indexes between various groups ( P >0.05).It is feasible to use silage sweet sorghum to feed dairy cows,but the proportion should not be too large,and attention sh 展开更多
关键词 SILAGE sweet sorghum SILAGE maize Additive Production performance BLOOD biochemical index HOLSTEIN COW
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Achieving strength-ductility synergy in cold spray additively manufactured Al/B4C composites through a hybrid post-deposition treatment
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作者 Naeem ul Haq Tariq Lawrence Gyansah +6 位作者 Xiang Qiu Chunnijia Hasan Bin Awais Chengwu Zheng Hao Du Jiqiang Wang Tianying Xiong 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第6期1053-1063,共11页
Cold spray additive manufacturing(CSAM) provides a potential solid state manufacturing route to fabricate variety of aluminum matrix composites(AMCs) with reduced possibility of undesired chemical reactions and residu... Cold spray additive manufacturing(CSAM) provides a potential solid state manufacturing route to fabricate variety of aluminum matrix composites(AMCs) with reduced possibility of undesired chemical reactions and residual thermal stresses. This study presents a hybrid(i.e. hot compression + hot rolling)post-deposition treatment to reinvigorate the mechanical properties of cold spray additively manufactured Al/B4 C composites. The as-deposited samples were initially subjected to 30% thickness reduction via hot compression treatment at 500°C followed by a hot rolling treatment with 40% thickness reduction in 2 passes. Electron backscatter diffraction(EBSD) and high resolution transmission electron microscopy(HRTEM) results revealed that after hybrid post-deposition treatment(involving 70%accumulative thickness reduction), the aluminum grains in the matrix were extensively refined due to simultaneous operation of continuous dynamic recrystallization(CDRX) and geometric dynamic recrystallization(GDRX). Furthermore, interfacial defects were remarkably reduced while the nature of Al/Al and Al/B4C interfacial bonding was changed from sheer mechanical interlocking to metallurgical bonding which facilitated efficient transference of applied load to uniformly dispersed bimodal B4C particles. As a result, ultimate tensile strength(UTS) and elongation(EL) of the as-deposited sample were simultaneously improved from 37 to 185 MPa and 0.3% to 6.2%, respectively. 展开更多
关键词 Cold spray additive manufacturing Post-deposition treatments Al/B4C COMPOSITES Dynamic recrystallization Mechanical properties
Synthesis of water-soluble Cu nanoparticles and evaluation of their tribological properties and thermal conductivity as a water-based additive
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作者 Junhua ZHAO Guangbin YANG +3 位作者 Chunli ZHANG Yujuan ZHANG Shengmao ZHANG Pingyu ZHANG 《摩擦(英文版)》 CSCD 2019年第3期246-259,共14页
Efficient and sustainable use of water-based lubricants is essential for energy efficiency.Therefore,the use of water-lubricated mechanical systems instead of conventional oil lubricants is extremely attractive from t... Efficient and sustainable use of water-based lubricants is essential for energy efficiency.Therefore,the use of water-lubricated mechanical systems instead of conventional oil lubricants is extremely attractive from the viewpoint of resource conservation.In this study,water-soluble Cu nanoparticles of size approximately 3 nm were prepared at room temperature(around 25 °C) via in-situ surface modification.The tribological behavior of the as-synthesized Cu nanoparticles as an additive in distilled water was evaluated using a universal micro-tribotester.The results show that the as-synthesized Cu nanoparticles,as a water-based lubricant additive,can significantly improve the tribological properties of distilled water.In particular,the lowest friction coefficient of 0.06 was obtained via lubrication with a concentration of 0.6 wt% of Cu nanoparticles in distilled water,which is a reduction of 80.6% compared with that obtained via lubrication with distilled water alone.It is considered that some Cu nanoparticles entered the contact area of the friction pairs to form a complex lubricating film and prevent direct contact of the friction pairs.Furthermore,some Cu nanoparticles in the solution accelerate the heat transfer process,which also results in good tribological properties. 展开更多
关键词 Cu nanoparticles WATER-SOLUBLE LUBRICANT ADDITIVE TRIBOLOGICAL properties
High mechanical strengths and ductility of stainless steel 304L fabricated using selective laser melting
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作者 Q.B. Nguyen Z. Zhu +3 位作者 F.L. Ng B.W. Chu S.M.L. Nai J. Wei 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第2期388-394,共7页
Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 L fully ... Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 L fully dense samples were successfully printed using the 3 D systems – ProX 300 printing machine. The ductility and tensile yield strength were almost two and three times higher compared to those of ASTM cast’s alloy. Honey comb like nano-cellular structure with different orientation was observed in the fine grains(~4μm) due to fast cooling rate. In addition, the formation of martensite phase in random grains is also a contributor to the strengths. Furthermore, negative residual stresses in the build and horizontal directions were detected and assisted further increase in the tensile strength. Fractography revealed the ductile feature of plastic deformation and the crack openings at unmelted particles or pores. 展开更多
关键词 ADDITIVE manufacturing STAINLESS steel POWDER Selective laser MELTING
日粮中添加牛至精油对牛肉脂肪酸以及血液生化指标的影响 预览
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作者 刘立山 周瑞 +4 位作者 吴建平 王彩莲 宋淑珍 韦胜 郎侠 《中国饲料》 北大核心 2019年第13期47-51,共5页
为研究日粮中添加牛至精油对牛肉脂肪酸以及血液生化指标含量的影响,试验选择10头体重相近、健康的荷斯坦奶公牛,随机平均分成试验组(每头添加牛至精油28 g/d)和对照组(未添加牛至精油),每组5头,相同环境下饲喂8个月后屠宰。结果显示:... 为研究日粮中添加牛至精油对牛肉脂肪酸以及血液生化指标含量的影响,试验选择10头体重相近、健康的荷斯坦奶公牛,随机平均分成试验组(每头添加牛至精油28 g/d)和对照组(未添加牛至精油),每组5头,相同环境下饲喂8个月后屠宰。结果显示:添加牛至精油组血液中总蛋白、白蛋白显著升高(P < 0.05);甘油三酯显著降低(P < 0.05);对半腱肌饱和脂肪酸(SFA)和不饱和脂肪酸(UFA)均无显著影响(P > 0.05),但使多不饱和脂肪酸(PUFA)含量显著升高(P < 0.05),P/S值增大(P < 0.05),显著提高了油酸以及亚油酸含量。因此日粮中添加牛至精油可有效改善牛肉脂肪酸组成含量和血液生化指标。 展开更多
关键词 牛至精油 添加剂 脂肪酸 血液生化指标
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铁尾矿砂水泥混凝土性能研究 预览
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作者 胡英俊 《公路交通技术》 2019年第3期13-19,共7页
为了研究铁尾矿砂对混凝土和易性和力学性能的影响,采用坍落度试验和抗折、抗压试验结果分析了不同种类、不同比例的外掺剂对铁尾矿混凝土性能的影响。结果表明:1)铁尾矿砂对混凝土和易性影响较大,其抗折、抗压强度在铁尾矿砂掺入量25%... 为了研究铁尾矿砂对混凝土和易性和力学性能的影响,采用坍落度试验和抗折、抗压试验结果分析了不同种类、不同比例的外掺剂对铁尾矿混凝土性能的影响。结果表明:1)铁尾矿砂对混凝土和易性影响较大,其抗折、抗压强度在铁尾矿砂掺入量25%时达到最佳;2)以25%铁尾矿砂为标准组,对不同外掺剂进行配合比设计,研究在铁尾矿砂基础上外掺剂对混凝土性能的影响。以粉煤灰取代水泥,随着掺量增多,7d强度降低,90d强度增加;以硅灰代替水泥,随着掺量增多,坍落度先增加再降低,强度增大;以矿渣代替水泥,随着掺量增多,流动性变好,强度增大。 展开更多
关键词 铁尾矿混凝土 外掺剂 和易性 抗折强度 抗压强度
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高效液相色谱法测定食品中安赛蜜、山梨酸、苯甲酸、糖精钠、脱氢乙酸的过程优化研究 预览
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作者 董字铁 《广东化工》 CAS 2019年第20期116-117,共2页
通过在流动相中引入甲酸并调控梯度程序里流动相中有机相的比例,优化了应用于食品中安赛蜜、苯甲酸、山梨酸、糖精钠及脱氢乙酸等甜味剂和防腐剂检测的高效液相色谱测定法。结果表明,测定方法的优化有效地避免了组分间的相互干扰,实现... 通过在流动相中引入甲酸并调控梯度程序里流动相中有机相的比例,优化了应用于食品中安赛蜜、苯甲酸、山梨酸、糖精钠及脱氢乙酸等甜味剂和防腐剂检测的高效液相色谱测定法。结果表明,测定方法的优化有效地避免了组分间的相互干扰,实现了五种添加剂的高效、快捷和同时测量。 展开更多
关键词 高效液相色谱法 添加剂 色谱分析
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Tribological performance of tributylmethylammonium bis(trifluoromethylsulfonyl)amide as neat lubricant and as an additive in a polar oil
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作者 Rubén GONZáLEZ Diego RAMOS +4 位作者 David BLANCO Alfonso FERNáNDEZ-GONZáLEZ Jose L.VIESCA Mark HADFIELD Antolin HERNáNDEZ BATTEZ 《摩擦(英文版)》 CSCD 2019年第3期282-288,共7页
The ionic liquid(IL) tributylmethylammonium bis(trifluoromethylsulfonyl)amide([N4441][NTf2]) was used as neat lubricant and as an additive(1.5 wt%) in a polar oil to study its friction and wear reducing properties.Tri... The ionic liquid(IL) tributylmethylammonium bis(trifluoromethylsulfonyl)amide([N4441][NTf2]) was used as neat lubricant and as an additive(1.5 wt%) in a polar oil to study its friction and wear reducing properties.Tribological tests were completed for 90 minutes at room temperature and 100 °C in a reciprocating configuration at loads of 30 and 70 N,10 Hz-frequency,and 4 mm stroke length.Wear volume was measured by confocal microscopy and the surface-IL interaction determined by XPS.The main findings were that neat IL showed the best tribological behavior;the IL-containing mixture behaved similar to the base oil regarding friction,however outperformed the antiwear behavior of the base oil under higher temperature;surface-IL chemical interaction was found mainly at 100 °C. 展开更多
关键词 ionic liquid ADDITIVE friction wear POLAR OIL
阻燃高分子材料的开发及其应用研究进展 预览
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作者 贾园 张鹏 +1 位作者 刘振 韩敏 《中国塑料》 CAS CSCD 北大核心 2019年第10期120-127,共8页
在介绍阻燃高分子材料开发的基础上,对阻燃高分子制备的研究情况进行了综述,包括分子内杂化阻燃高分子、添加机型阻燃高分子等,同时总结了阻燃高分子的应用范围,并展望了其未来的研究方向。
关键词 高分子材料 阻燃 添加剂 工程材料 合成
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Synthesis of jet fuel additive with cyclopentanone 预览
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作者 Hao Tang Fang Chen +7 位作者 Guangyi Li Xiaofeng Yang Yancheng Hu Aiqin Wang Yu Cong Xiaodong Wang Tao Zhang Ning Li 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第2期23-30,共8页
A new route was developed for the synthesis of renewable decalin with cyclopentanone which can be derived from lignocellulose.It was found that 1,2,3,4,5,6,7,8-octahydronaphthalene could be selectively produced by the... A new route was developed for the synthesis of renewable decalin with cyclopentanone which can be derived from lignocellulose.It was found that 1,2,3,4,5,6,7,8-octahydronaphthalene could be selectively produced by the hydrogenation/dehydration/rearrangement of [1,1-bi(cyclopentylidene)]-2-one(i.e.the selfaldol condensation product of cyclopentanone) over a dual-bed catalyst system.Among the investigated catalysts,the Ru/C and Amberlyst-15 resin exhibited the highest activities for the hydrogenation of [1,1-bi(cyclopentylidene)]-2-one to [1,1-bi(cyclopentan)]-2-ol and the dehydration/rearrangement of [1,1-bi(cyclopentan)]-2-ol to 1,2,3,4,5,6,7,8-octahydronaphthalene,respectively.Using Ru/C and Amberlyst-15 resin as the first bed and the second bed catalysts,1,2,3,4,5,6,7,8-octahydronaphthalene was directly produced in high carbon yield(83.7%) under mild conditions(393 K,1 MPa).After being hydrogenated,the1,2,3,4,5,6,7,8-octahydronaphthalene was converted to decalin which can be used as additive to improve the thermal stability and volumetric heat value of jet fuel. 展开更多
关键词 LIGNOCELLULOSE Jet fuel ADDITIVE ALDOL condensation Dehydration/rearrangement Hydrogenation
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Ultra‐low cost Ti powder for selective laser melting additive manufacturing and superior mechanical properties associated 预览
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作者 Yuhang Hou Bin Liu +5 位作者 Yong Liu Yinghao Zhou Tingting Song Qi Zhou Gang Sha Ming Yan 《光电进展(英文)》 2019年第5期10-17,共8页
One of the bottleneck issues for commercial scale-up of Ti additive manufacturing lies in high cost of raw material, i.e. the spherical Ti powder that is often made by gas atomization. In this study, we address this s... One of the bottleneck issues for commercial scale-up of Ti additive manufacturing lies in high cost of raw material, i.e. the spherical Ti powder that is often made by gas atomization. In this study, we address this significant issue by way of powder modification & ball milling processing, which shows that it is possible to produce printable Ti powders based on ultra- low cost, originally unprintable hydrogenation-dehydrogenation (HDH) Ti powder. It is also presented that the as-printed Ti using the modified powder exhibits outstanding mechanical properties, showing a combination of excellent fracture strength (~895 MPa) and high ductility (~19.0% elongation). 展开更多
关键词 selective laser melting POWDER modification hydrogenation-dehydrogenation (HDH) TI ball MILLING additive manufacturing
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聚丙烯装置不合格料产生原因及解决方案 预览
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作者 雷佳伟 《广州化工》 CAS 2019年第10期131-132,148共3页
实际生产中,不合格料的产生是聚丙烯装置在挤压造粒过程中常见的不良现象。不合格料的出现,不仅会影响装置的正常运行,甚至可引发客户对产品质量的投诉而造成经济损失。本文研究了不合格料的产生原因,包括造粒设备、造粒工艺、聚合工艺... 实际生产中,不合格料的产生是聚丙烯装置在挤压造粒过程中常见的不良现象。不合格料的出现,不仅会影响装置的正常运行,甚至可引发客户对产品质量的投诉而造成经济损失。本文研究了不合格料的产生原因,包括造粒设备、造粒工艺、聚合工艺及添加剂配方等。为了有效减少不合格料,可采取如下解决方案,即综合优化挤出造粒设备与造粒工艺,优化聚合工艺及改进聚合装置的设计制造,优化添加剂配方。 展开更多
关键词 聚丙烯 不合格料 造粒工艺 聚合工艺 添加剂
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Highly efficient and thermal stable guanidinium-based two-dimensional perovskite solar cells via partial substitution with hydrophobic ammonium
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作者 Yingzhu Zhang Jiehuan Chen +5 位作者 Xiaomei Lian Weitao Yang Jun Li Shuoxun Tian Gang Wu Hongzheng Chen 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第7期859-865,共7页
Layered two-dimensional(2D)perovskite solar cells(PVSCs)with a chemical formula of C(NH2)3(CH3NH3)3Pb3I10(n=3)have been fabricated through additive engineering,wherein stoichiometrically equivalent guanidinium(GA+)and... Layered two-dimensional(2D)perovskite solar cells(PVSCs)with a chemical formula of C(NH2)3(CH3NH3)3Pb3I10(n=3)have been fabricated through additive engineering,wherein stoichiometrically equivalent guanidinium(GA+)and methylammonium(MA+)serve as spacer cations.The crystallinity of the perovskite films is dramatically enhanced with proper amount of methylammonium thiocyanate(MASCN)added into the precursor solution.In addition,we substitute a small amount of MA+with hydrophobic phenylethylammonium(PEA+),which can passivate trap states of the perovskite films.As a result,the open circuit voltage increases to 1.1 V and the best power conversion efficiency(PCE)of 10.12%is yielded.Furthermore,superior thermal stability and balanced moisture stability of the PEA-substituted GA-based PVSCs are demonstrated,compared to the popular 3D MAPbI3and 2D PEA-based PVSCs.They retain approximately 80%of the original PCE after 30 d at 20%relative humidity(RH),and 50%of the original PCE after 3200 min at 85°C without any encapsulation.This work suggests a new route to achieve both heat and humidity stable PVSCs by simply mixing different spacer cations. 展开更多
关键词 guanidinium-based 2D PEROVSKITE solar cells additive engineering PEA substitution stability
微波协同化学助剂强化脱除煤中硫 预览
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作者 周丙义 周涛 +1 位作者 李洋 葛涛 《洁净煤技术》 CAS 2019年第3期49-55,共7页
硫是煤中主要有害元素,煤炭利用过程中硫的排放是酸雨的重要成因,脱硫是煤炭洁净利用的研究热点之一。微波具有促进反应发生、加快反应速率的作用,微波协同化学助剂脱硫是煤炭脱硫的重要手段。本文通过微波辐照结合3种化学助剂研究煤中... 硫是煤中主要有害元素,煤炭利用过程中硫的排放是酸雨的重要成因,脱硫是煤炭洁净利用的研究热点之一。微波具有促进反应发生、加快反应速率的作用,微波协同化学助剂脱硫是煤炭脱硫的重要手段。本文通过微波辐照结合3种化学助剂研究煤中硫的脱除效果,利用正交试验考察微波辐照时间、化学助剂种类和煤种对脱硫效果的影响。结果表明,煤种对微波协同不同助剂的脱硫效率影响较大,所选3种煤样的最佳辐照时间各不相同;硝酸与微波联合的脱硫效果最好,其中贵州(GZ)煤在微波协同硝酸作用下,全硫脱除率可达71.2%。形态硫测试分析表明煤样经脱硫后无机硫脱除效率较高,最高可达90.5%,有机硫脱除效率在20%~40%。XRD谱图分析显示微波协同化学助剂脱硫后,煤中主要矿物和煤质结构没有明显变化,微波在脱除煤中硫分的同时可保持煤炭基质稳定。XPS谱图分析表明,煤样硫醚(醇)类有机硫脱除效果较好,脱除率可达49.4%,亚砜类略低,脱除率为23%~28%,噻吩类有机硫脱除效果最差,脱除率在10%~20%。 展开更多
关键词 煤炭 脱硫 微波 助剂 XRD XPS
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食用香精在烘焙食品中的应用 预览
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作者 赵秀艳 《现代食品》 2019年第5期18-19,共2页
烘培在大多数国家都是很普遍的烹饪方式。在中国,烘培可以说是一个外来词,源于“baking”。香精可以为食物带来特殊的味道和口感,逐渐成为广泛运用于烘培食品的重要食品添加剂。
关键词 食用香精 烘培 添加剂
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饲料添加剂混合机的选用 预览
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作者 周玉姣 罗斌 +3 位作者 梁卫 周扬 邱瑜 王进红 《南方农机》 2019年第21期1-2,6共3页
饲料添加剂是饲料的重要组成部分,混合是添加剂质量保证的关键工艺,混合设备的选用取决于企业的生产工艺和特点。本文分析了生产中典型的添加剂混合机结构及混合原理,讨论了各种设备的特点,企业可根据生产规模和工艺要求进行选择。
关键词 饲料 添加剂 混合机 变异系数
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