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Thermoelectric Properties of Mg_2Si_(1-x)Sn_x Synthesized by Bulk Mechanical Alloying

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Chinese Journal of Aeronautics 2006年第B12期19卷 134-138页

作者： song ren-bo LIU Ya-zheng Tatsuhiko AIZAWA School of Material Science and Engineering University of Science and Technology Beijing Beijing 100083 China Jayram Office University of Toronto Shanghai International Building 6F 1-24-12 Shinkawa Chuo-ku Tokyo 104-0033 Japan

Bulk mechanical alloying （BMA） has been successfully applied to solid-state synthesis of p-type and n-type thermoelectric materials Mg2Si1-xSnx （x = 0, 0.2, 0.4, 0.6, 0.8, 1） from element-powders at the room temperature in a relatively short time. The electrical conductivity, the Seebeck coefficient and the thermal conductivity of the Mg2Si1-xSnx are quite sensitive to the x-content. With the x-content rising, the electrical conductivity increases. When x = 0.6, it reaches the lowest and Mg2Si shows an n-type of semi-conducting However, when x = 0.2 and T 〉525 K, the Seebeck coefficient of the samples will change the opposite way. While x≥0.4, the samples present a p-type of semi-conducting. The figure of merit, Z of Mg2Si1-xSnx will be obtained in the range from 300 K to 700 K. When x = 0.6, Z proves to be higher than that of other samples at 300 K≤ T≤650 K.

关键词： solid-state synthesis thermoelectric bulk mechanical alloying Mg2Si1-xSnx

Characteristics of Mechanical Properties and Microstructure for 316L Austenitic Stainless Steel

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Journal of Iron and Steel Research International 2011年第11期18卷 53-59页

作者： song ren-bo XIANG Jian-ying HOU Dong-po School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

A comparative study on mechanical properties and microstructure of 316L austenitic stainless steel between solution treated specimen and hot rolled specimen was conducted. After a specimen was subjected to solution treatment at 1 050 ℃ for 6 min, its mechanical properties were determined through tensile and hardness tests. Based on the true stress vs true strain and engineering stress vs engineering strain flow curves, the work hardening rate has been explored. The results show that the solution treated specimen has an excellent combination of strength and elongation, and that this steel is easy to work-hardening during deformation. Optical microscope, scanning electron micro- scope, transmission electron microscope and X-ray diffraction examinations were conducted, these reveal that twins in 316L austenitic stainless steel can be divided into suspended twin and transgranular twin which have different for mation mechanisms in growth, and that the deformation induced martensite nucleated and grown in the shear band intersections can be observed, and that the fracture surfaces are mainly composed of dimples and exhibit a tough fracture character.

关键词： 316L mechanical property twin martensite fracture morphology

Processing effects on the magnetic and mechanical properties of FeCoNiAl_(0.2)Si_(0.2) high entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 549-555页

作者： Ting-ting Zuo song-bo ren Peter K. Liaw Yong Zhang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing Hangke Engine Control System Science & Technology Co. Ltd. Department of Materials Science and Engineering The University of Tennessee

High entropy alloys with the composition of FeCoNiA10.2Si0.2 were prepared by arc melting and induction melting, denoted by A1 and A2, respectively. The samples prepared by these two techniques have a face-centered cubic （FCC） phase structure and a typical dendrite morphology. The tensile yield strength and maximum strength of A2 samples are about 280 and 632 MPa, respectively. Moreover~ the elongation can reach 41.7%. These two alloys prepared by the different methods possess the similar magnetic properties. The saturation magnetization and coercivity can reach 1.151 T and 1400 A/m for A1 samples and 1.015 T and 1431 A/m for A2 samples, respectively. Phases in A2 samples do not change, which are heat treated at different temperatures, then quenched in water. Only the sample, which is heat treated at 600~C for 3 h and then furnace cooled, has a new phase precipitated. Besides, the coercivity decreases obviously at this temperature. Cold rolling and the subsequent heat treatment cannot improve the magnetic properties effectively. However, cold rolling plays an important role in improving the strength.

关键词： high entropy alloys magnetic properties mechanical properties heat treatment

A Selective‑Response Hypersensitive Bio‑Inspired Strain Sensor Enabled by Hysteresis Effect and Parallel Through‑Slits Structures

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Nano-Micro Letters 2024年第2期16卷 139-153页

作者： Qun Wang Zhongwen Yao Changchao Zhang Honglie song Hanliang Ding bo Li Shichao Niu Xinguan Huang Chuanhai Chen Zhiwu Han Luquan ren Key Laboratory of Bionic Engineering(Ministry of Education) Jilin UniversityChangchunJilin 130022People’s Republic of China Liaoning Academy of Materials LiaoningShenyang 110167People’s Republic of China Key Laboratory of CNC Equipment Reliability(Ministry of Education) Jilin UniversityChangchunJilin 130022People’s Republic of China

Flexible strain sensors are promising in sensing minuscule mechanical signals,and thereby widely used in various advanced ***,the effective integration of hypersensitivity and highly selective response into one flexible strain sensor remains a huge ***,inspired by the hysteresis strategy of the scorpion slit receptor,a bio-inspired flexible strain sensor(BFSS)with parallel through-slit arrays is designed and ***,BFSS consists of conductive monolayer graphene and viscoelastic styrene–isoprene–styrene block *** the synergistic effect of the bio-inspired slit structures and flexible viscoelastic materials,BFSS can achieve both hypersensitivity and highly selective frequency ***,the BFSS exhibits a high gage factor of 657.36,and a precise identification of vibration frequencies at a resolution of 0.2 Hz through undergoing different morphological changes to high-frequency vibration and low-frequency ***,the BFSS possesses a wide frequency detection range(103 Hz)and stable durability(1000 cycles).It can sense and recognize vibration signals with different characteristics,including the frequency,amplitude,and *** work,which turns the hysteresis effect into a"treasure,"can provide new design ideas for sensors for potential applications including human–computer interaction and health monitoring of mechanical equipment.

关键词： Bio-inspired strain sensors Hysteresis effect Hypersensitivity Selective frequency response Health monitoring applications

倾斜板法制备9Cr18半固态坯料二次重熔的微观组织演变

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工程科学学报 2021年第2期43卷 248-254页

作者：王永金宋仁伯北京科技大学材料科学与工程学院北京100083

研究利用倾斜板法制备的9Cr18半固态坯料在二次重熔过程中微观组织演变,以期对后续触变成形提供必要的理论基础.研究结果表明,采用倾斜板浇注法可以得到优质的9Cr18半固态坯料,其典型组织为初生固相奥氏体(γ1)球状晶粒和晶界网状组织构... 详细信息

研究利用倾斜板法制备的9Cr18半固态坯料在二次重熔过程中微观组织演变,以期对后续触变成形提供必要的理论基础.研究结果表明,采用倾斜板浇注法可以得到优质的9Cr18半固态坯料,其典型组织为初生固相奥氏体(γ1)球状晶粒和晶界网状组织构成,网状组织为二次奥氏体(γ2)和M7C3碳化物液相共晶组织.球状晶粒的平均直径为93.5μm,形状因子0.69,半固态坯料球状晶粒边界光滑,大小相对均匀.固液两相中Fe、C、Cr存在着明显的元素差异.液相组织中Cr、C元素富集,固相中Fe含量较高.采用波浪形倾斜板法制备的9Cr18合金半固态坯料重熔组织形貌优于传统铸锭重熔组织.半固态坯料重熔后的组织化学成分更为均匀,晶粒也更圆整,固液界面平滑,且加热温度越高,晶粒越圆整,液相率越高.二次重熔后碳化物尺寸明显减小,平均宽度仅为0.5μm,长度大大减小使得其形态接近粒状.

关键词：倾斜板法 9Cr18不锈钢半固态坯料二次重熔组织演变

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310S耐热不锈钢高温循环氧化性能

钢铁研究学报 2017年第10期29卷 844-851页

作者：任培东宋仁伯甘肃酒钢集团宏兴钢铁股份有限公司甘肃嘉峪关735100 北京科技大学材料科学与工程学院北京100083

研究了310S耐热不锈钢在800、900、1000、1100、1200℃时高温循环氧化性能,采用SEM、XRD、EDS对高温循环氧化生成物进行分析。实验结果表明:1000℃以下时,钢的氧化速率较为缓慢,当温度达到1200℃时其氧化速率急剧增加。310S耐热不锈钢... 详细信息

研究了310S耐热不锈钢在800、900、1000、1100、1200℃时高温循环氧化性能,采用SEM、XRD、EDS对高温循环氧化生成物进行分析。实验结果表明:1000℃以下时,钢的氧化速率较为缓慢,当温度达到1200℃时其氧化速率急剧增加。310S耐热不锈钢高温循环氧化产物分为3层,外层是FeO·Cr2O3和尖晶石结构的MnCr2O4,中间为Cr2O3,内层为SiO2氧化膜,这种结构是其具有良好耐高温氧化性能的主要原因。

关键词：耐热不锈钢循环氧化耐高温氧化氧化膜

A Practical Approach for Missing Wireless Sensor Networks Data Recovery

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China Communications 2024年第5期21卷 202-217页

作者： song Xiaoxiang Guo Yan Li Ning ren Bing The College of Communications Engineering Army Engineering University of PLANanjing 210007China The 63891 Unit of PLA Luoyang 471000China

In wireless sensor networks(WSNs),the performance of related applications is highly dependent on the quality of data ***,missing data is almost inevitable in the process of data acquisition and *** methods often rely on prior information such as low-rank characteristics or spatiotemporal correlation when recovering missing WSNs ***,in realistic application scenarios,it is very difficult to obtain these prior information from incomplete data ***,we aim to recover the missing WSNs data effectively while getting rid of the perplexity of prior *** designing the corresponding measurement matrix that can capture the position of missing data and sparse representation matrix,a compressive sensing(CS)based missing data recovery model is ***,we design a comparison standard to select the best sparse representation basis and introduce average cross-correlation to examine the rationality of the established ***,an improved fast matching pursuit algorithm is proposed to solve the *** results show that the proposed method can effectively recover the missing WSNs data.

关键词： average cross correlation matching pursuit missing data wireless sensor networks

Surfactant-assisted crystallization of lysozyme and its mechanism

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Particuology 2024年第7期90卷 199-208页

作者： Yujie song Rongfei ren Min Su Zhihan Liang Qi Hao School of Chemical Engineering Hebei University of TechnologyTianjin 300130China

Surfactants were used to assist in the crystallization of *** types of surfactants with different structures(sodium dodecyl sulfate,cetyltrimethylammonium bromide,or betaine hydrochloride[BH])were *** study indicated that three surfactants were all capable of shortening the crystallization induction time of lysozyme,with BH inducing the shortest crystallization induction time(t=1 min)and the largest crystal size(37μm).The molecular interactions among each of the three surfactants aforementioned and lysozyme were also investigated by *** was found that hydrogen bonding dominantly acted between the carboxyl structure of the surfactant BH and the lysozyme,which produced the most favorable conformation for the self-assembly of lysozyme(promote lysozyme orderly aggregation and shorten the crystallization induction time).On this basis,the mechanism of surfactant-promoted lysozyme crystallization was proposed.

关键词： Protein Crystallization Surfactant Lysozyme Molecular interaction Mechanism

Economic analysis of rooftop photovoltaics system under different shadowing conditions for 20 cities in China

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Building Simulation 2024年第2期17卷 235-252页

作者： Zhiyi ren Yixing Chen Chengcheng song Mengyue Liu Anni XuQilin Zhang College of Civil Engineering Hunan UniversityChangsha410082China Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education Hunan UniversityChangsha410082China

Installing photovoltaic(PV)systems is an essential step for low-carbon *** economics of PV systems are strongly impacted by the electricity price and the shadowing effect from neighboring *** study evaluates the PV generation potential and economics of 20 cities in China under three shadowing ***,the building geometry models under three shadowing conditions for the 20 cities were constructed using ***,60 building models with PV systems and shadows from surrounding buildings were generated by City Buildings,Energy,and Sustainability(CityBES),an open platform,to simulate the PV power ***,the study presented one economic analysis model to evaluate the profitability by combining the market cost of rooftop PV systems and electricity prices in *** economic model included four indicators:payback period(static and dynamic),net present value(NPV),and internal rate of return(IRR).The results show that the reduction of PV power generation ranges from 8.29%to 16.01%under medium shadowing,and experiences a maximum decrease of up to 39.71%under high *** economic analysis shows that almost all the regions show reliable potential,obtaining an IRR higher than the reference value(5%).Nenjiang has the highest economic profit,with the highest NPV(86,181.15 RMB)and IRR(30.14%)under no shadowing among 20 *** also should be mentioned that the alignment between electricity price distribution and the solar power generation curve will directly impact the economic potential of PV systems.

关键词： rooftop photovoltaic system EnergyPlus economic analysis shadowing buildings electric price