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Vacuum brazing TiAl intermetallic to K4169 alloy using amorphous filler metals Ti_(56.25–x)Zr_(x)Ni_(25)Cu1_(8.75)

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Journal of Materials Science & Technology 2023年第23期154卷 217-231页

作者： liangliang zhang Honggang Dong Peng Li Shuai Li Baosheng Wu Yueting Ma Libing Huang Chao Li Jiachen Li Yuesen Yang School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China School of Mechanical Engineering North China University of Water Resources and Electric Power Zhengzhou 450045 China

A series of Ti_(56.25-x)Zr_(x)Ni_(25)Cu1_(8.75)(x=0–25,at.%) filler metals were designed based on a cluster-plus-glue-atom model to vacuum braze TiAl intermetallic to K4169 alloy. The impact of Zr content on the interfacial microstructure and shear strength of joints was examined. And the relationship between the interfacial lattice structure and the fracture behavior of the joint was investigated. The findings reveal a sectionalized characteristic with three reaction zones (Zone I, Zone II and Zone III) in the microstructure of the TiAl intermetallic to K4169 alloy joint. As the Zr content in filler metals increased, the diffusion of Ti transitioned from long-distance to short-distance in Zone I, changing the initial composition from TiNi_(3) /TiNi/NiNb/(Cr, Fe, Ni)SS to NiCrFe/(Cr, Fe, Ni)SS /TiNi. In Zone II, the initial composition altered from TiNi_(3) /TiNi to TiNi/Ti_(2) Ni/TiNi_(3) /TiCu/TiNi. The interface between Zones II and III altered from a non-coherent and semi-coherent interface of TiNi/TiAl/Ti_(3) Al with significant residual stress to a semi-coherent interface of TiNi/TiNi_(3) /TiAl_(2) /Ti_(3) Al with a gradient distribution. The shear strength of the joint initially decreased and then increased. When the Zr content of filler metal was 25 at.%, the shear strength of the joint reached 288 MPa. The crack initiation position changed from non-coherent TiNi/TiAl interface with high angle grain boundaries (HAGBs) and lattice mismatch of 65.86 at.% to a semi-coherent Ti3 Al/TiAl2 interface with a lattice mismatch of 20.07 at.% when the Zr content increased. The brittle fracture was present on the fracture surfaces of all brazed joints.

关键词： Vacuum brazing TiAl intermetallic to K4169 alloy brazed joint Ti-Ni based amorphous filler metal EBSD Lattice mismatch

Practical continuous-variable quantum key distribution with feasible optimization parameters

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Science China(Information Sciences) 2023年第8期66卷 80-91页

作者： Li MA Jie YANG Tao zhang Yun SHAO Jinlu LIU Yujie LUO Heng WANG Wei HUANG Fan FAN Chuang ZHOU liangliang zhang Shuai zhang Yichen zhang Yang LI Bingjie XU Science and Technology on Communication Security Laboratory Institute of Southwestern Communication State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

Continuous-variable quantum key distribution(CV-QKD) offers an approach to achieve a potential high secret key rate(SKR) in metropolitan areas. There are several challenges in developing a practical CV-QKD system from the laboratory to the real world. One of the most significant points is that it is really hard to adapt different practical optical fiber conditions for CV-QKD systems with unified hardware. Thus,how to improve the performance of practical CV-QKD systems in the field without modification of the hardware is very important. Here, a systematic optimization method, combining the modulation variance and error correction matrix optimization, is proposed to improve the performance of a practical CV-QKD system with a restricted capacity of postprocessing. The effect of restricted postprocessing capacity on the SKR is modeled as a nonlinear programming problem with modulation variance as an optimization parameter,and the selection of an optimal error correction matrix is studied under the same scheme. The results show that the SKR of a CV-QKD system can be improved by 24% and 200% compared with previous frequently used optimization methods theoretically with a transmission distance of 50 km. Furthermore, the experimental results verify the feasibility and robustness of the proposed method, where the achieved optimal SKR achieved practically deviates <1.6% from the theoretical optimal value. Our results pave the way to deploy high-performance CV-QKD in the real world.

关键词： continuous-variable quantum key distribution post-processing optimization secret key rate

Spatiotemporal patterns of winter wheat phenology and its climatic drivers based on an improved pDSSAT model

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Science China Earth Sciences 2021年第1期64卷 2144-2160页

作者： Yuchuan LUO Zhao zhang liangliang zhang Juan CAO Academy of Disaster Reduction and Emergency Management Minsitry of Emergency Management&Ministry of Education School of National Safety and Emergency ManagementBeijing Normal UniversityBeijing100875China

Acquiring spatiotemporal patterns of phenological information and its drivers is essential for understanding the response of crops to climate change and implementing adaptation ***,current approaches to obtain phenology and analyse its drivers have deficiencies such as sparse observations,excessive dependence of remote sensing inversion on sensors,and inevitable difficulties in upscaling site-based crop models into larger *** on the Wang-Engel temperature response function,we improved the Crop Estimation through Resource and Environment Synthesis-Wheat(CERES-Wheat)***,we calibrated the model at the regional scale and evaluated its ***,the spatiotemporal changes in winter wheat phenology in China from 2000 to 2015 were *** results showed that the improved model significantly enhanced the simulation accuracy of the anthesis and maturity dates by averages of 13%and 12%in most planting areas,especially in the Yunnan-Guizhou Plateau(YG)with improvements of 26%and 28%.The simulated phenology of winter wheat grown in a colder environment(e.g.,the average temperatures during the vegetative growth period range from 0 to 5℃ and from 15 to 20°C,and the reproductive growth period ranges from 10 to 15°C)also notably *** results confirmed that the original temperature response function indeed had *** analyses revealed that the key phenological dates and growth periods over the past 16 years were dominantly advanced and ***,the anthesis date,vegetative growth period(VGP),and reproductive growth period(RGP)indicated obviously spatial *** example,the anthesis date and VGP in the North China Plain(NCP)and the Middle-Lower Yangtze Plain(YZ)and the RGP in northwestern China(NW)showed opposite trends of delay and prolongation as comparing with the dominant *** analysis indicated that the key phenological dates and growth periods were advanced and sho

关键词： Winter wheat Phenology Temperature response function Spatiotemporal patterns pDSSAT

时效温度对Fe-30Mn-12Al-0.9C轻质高强钢组织和硬度的影响

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热加工工艺 2024年第11期53卷 121-124,128页

作者：刘世锋黄睿魏瑛康王建勇张亮亮贾文鹏王岩西安建筑科技大学冶金工程学院陕西西安710055

针对高Al、高Mn含量的轻质高强钢Fe-30Mn-12Al-0.9C,研究了时效温度对该钢相组成、组织和硬度的影响,通过OM、XRD等分析了不同时效温度下其微观组织的演变规律。结果表明:在低温时效时,该钢的时效组织和固溶组织差异较小,主要为奥氏体+... 详细信息

针对高Al、高Mn含量的轻质高强钢Fe-30Mn-12Al-0.9C,研究了时效温度对该钢相组成、组织和硬度的影响,通过OM、XRD等分析了不同时效温度下其微观组织的演变规律。结果表明:在低温时效时,该钢的时效组织和固溶组织差异较小,主要为奥氏体+铁素体,晶内存在纳米级别κ-碳化物,硬度变化幅度较小;500℃时效时,组织中出现β-Mn,硬度开始升高;当时效温度为650℃时,组织发生明显改变,晶界出现大量β-Mn,硬度明显升高;当时效温度达到700℃时,奥氏体彻底分解为铁素体和κ-碳化物,伴随着晶界处β-Mn和κ-碳化物的聚集长大,材料的硬度达到最大值66.3 HRC。

关键词：轻质高强钢时效温度显微组织洛氏硬度

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超大地面荷载下盾构工作井叠合结构的力学响应

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济南大学学报（自然科学版） 2024年第1期38卷 29-36,47页

作者：宋博刘俊岩刘燕宋享桦扈萍李春林张亮亮孙文昊济南大学土木建筑学院山东济南250022 济南城市建设集团有限公司山东济南250014 中铁第四勘察设计院集团有限公司湖北武汉430063

为了解决现行盾构工作井的设计缺乏对超大地面荷载作用的验算问题,通过开展室内缩尺模型试验,研究盾构工作井从施工期到服役期在超大地面荷载下地下连续墙与主体结构侧墙所构成叠合结构的力学响应,并考虑盾构工作井周围土体中地下水的作... 详细信息

为了解决现行盾构工作井的设计缺乏对超大地面荷载作用的验算问题,通过开展室内缩尺模型试验,研究盾构工作井从施工期到服役期在超大地面荷载下地下连续墙与主体结构侧墙所构成叠合结构的力学响应,并考虑盾构工作井周围土体中地下水的作用,探讨土体抗剪强度减小对超大地面荷载最大值的影响。结果表明:在超大地面荷载作用下,盾构工作井中隔墙的抗压刚度较大,以受压的形式承担了大量的荷载效应,导致叠合结构上部容易发生低应力水平下的整体水平位移,进而在围护结构底部发生失稳,导致整体破坏;主体结构侧墙在施工期的初始挠度及叠合结构整体水平位移使得叠合结构中地下连续墙承担了大部分内力;通过观测室内缩尺模型中叠合结构的变形量,由模型数据换算得到盾构工作井顶部极限超载为445.5 kPa,远大于盾构工作井周围土体地基承载力特征值130 kPa,验证了采用地基承载力对超大地面荷载下地面硬化进行设计的安全、可靠性。

关键词：盾构工作井叠合结构超大地面荷载模型试验地基承载力

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路域生态系统遥感监测发展趋势分析与展望

遥感技术与应用 2024年第2期39卷 470-477页

作者：文梦迪张亮亮万华伟余凡郅二铨施佩荣王永财孙晨曦中国环境科学研究院北京100012 生态环境部卫星环境应用中心北京100094 中国地质环境监测院中国地质调查局北京100081 北京建筑大学测绘与城市空间信息学院北京102627 首都师范大学资源环境与旅游学院北京100048

路域生态系统监测是掌握路域生态系统质量状况和变化原因的基础和关键环节,对于路域生态环境保护与可持续发展具有重要意义。由于具有大范围、多时相、高精度和综合性等优势,遥感技术逐渐成为路域生态监测的主流手段。本文从景观格局遥... 详细信息

路域生态系统监测是掌握路域生态系统质量状况和变化原因的基础和关键环节,对于路域生态环境保护与可持续发展具有重要意义。由于具有大范围、多时相、高精度和综合性等优势,遥感技术逐渐成为路域生态监测的主流手段。本文从景观格局遥感监测、植被状况遥感监测和物种多样性监测3个方面,回顾国内外相关方面的研究进展,总结研究趋势,指出现阶段研究面临的主要问题与挑战,并提出未来发展展望。研究表明:(1)路域生态系统遥感监测涵盖方面众多,研究成果丰富,不同方法具有各自的应用优势和不足;(2)路域生态系统遥感监测目前仍面临着针对公路建设期监测少、监测评价指标针对性弱、基于公路特点的遥感监测较少、路域范围划定不明确等诸多挑战。因此,未来研究应从多维角度,设立多项指标对路域建设期生态状况进行评价,根据陆路交通设施的线性工程特点,发展具有针对性的监测技术,提升监测效率和实时性。

关键词：路域生态学生态系统遥感监测

A computational simulation study for techno-economic comparison of conventional and stripping gas methods for natural gas dehydration

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Chinese Journal of Chemical Engineering 2020年第9期28卷 2285-2293页

作者： Muhammad Salman liangliang zhang Jianfeng Chen Research Centerof the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical TechnologyBeijing 100029China StateKey Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China

In the present work,the conventional natural gas dehydration method(CDM)and stripping gas method(SGM)are technically and economically analyzed,utilizing Aspen HYSYS and Aspen Process Economic Analyzer(APEA),*** optimize the CDM and SGM,the sensitivities of the water content of dry gas,reboiler duty and raw material loss are analyzed against solvent rate and stripping gas *** optimized processes are set to achieve a targeted value of water content in dry gas and analyzed at optimized *** analysis shows that SGM gives 46%lower TEG feed rate,42%lower reboiler duty and 99.97%pure regenerated ***,economic analysis reveals that SGM has 38%lower annual operating cost compared to *** to results,from both technical and economic point of view,SGM is more feasible for natural gas dehydration compared to CDM.

关键词： Natural gas dehydration Technical analysis Parametric optimization Economic study Aspen HYSYS

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功能性食品学教学改革探索

食品工业 2024年第2期45卷 231-233页

作者：郭妍郭怡琳冯赛赛徐建国张亮亮山西师范大学食品科学学院太原030031

功能性食品学是食品专业的一门核心课程,对于培养应用型高素质人才具有重要作用。以山西师范大学食品科学学院为例,从教学内容、教学模式和考核方式3个方面对课程体系进行优化。主要采用理论与实践有机融合、线上线下相结合的方式进行... 详细信息

功能性食品学是食品专业的一门核心课程,对于培养应用型高素质人才具有重要作用。以山西师范大学食品科学学院为例,从教学内容、教学模式和考核方式3个方面对课程体系进行优化。主要采用理论与实践有机融合、线上线下相结合的方式进行课程教学改革,旨在提高教学质量与效果,培养具有实际应用能力的功能性食品人才。

关键词：功能性食品学教学改革教学方法

选区激光熔化构建17-4PH钢残余奥氏体梯度分布

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钢铁 2024年第5期59卷 134-144,184页

作者：王岩田丰硕谢信亮韩李雄魏瑛康王建勇张亮亮贾文鹏刘世锋西安建筑科技大学冶金工程学院陕西西安710055 南京工业大学轻质高性能材料研究中心江苏南京211899

马氏体沉淀硬化(17-4PH)钢广泛应用于压缩机叶轮、水翼等具有复杂结构的过流部件。选区激光熔化(selective laser melting,SLM)作为一种新兴的近净成形技术,其逐点逐层的扫描堆叠制造方式有助于通过拓扑设计优化零部件结构和实现复杂形... 详细信息

马氏体沉淀硬化(17-4PH)钢广泛应用于压缩机叶轮、水翼等具有复杂结构的过流部件。选区激光熔化(selective laser melting,SLM)作为一种新兴的近净成形技术,其逐点逐层的扫描堆叠制造方式有助于通过拓扑设计优化零部件结构和实现复杂形状零部件的一体成形。采用“交叉双向式”和“双向式”两种扫描策略交替打印17-4PH钢,探究选区激光熔化构筑17-4PH钢中的残余奥氏体梯度分布方法。研究结果表明,通过调控扫描策略,改变了热量输入和散失方式,可以在17-4PH钢中实现残余奥氏体含量梯度分布。交叉双向扫描策略可有效细化马氏体晶粒,马氏体晶粒的大小与构建高度相关,残余奥氏体晶粒的大小与扫描模式和构建高度关系不大。交叉双向扫描形成的细小马氏体会对周围奥氏体产生附加应力,提高残余奥氏体稳定性,导致试样底部奥氏体较多。双向扫描冷却速度快,过冷度较大,马氏体转变的驱动力增大,消除相稳定,造成顶部马氏体较多,残余奥氏体少。随着堆积层数的升高,组织的冷却速度由慢变快,马氏体的转变程度增加,残余奥氏体含量减少。实现了17-4PH钢中奥氏体梯度组织的控制,这种梯度组织的制备为优化材料性能和实现多功能应用提供了新的途径。

关键词：选区激光熔化 17-4PH钢奥氏体马氏体梯度组织显微硬度

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