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Releasing the residual stress of C_(f)/SiC-GH3536 joint by designing an Ag-Cu-Ti+Sc_(2)(WO_(4))_(3) composite filler metal

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Journal of Materials Science & Technology 2022年第13期108卷 102-109页

作者： p.wang X.Liu H.wang J.Cao J.Qi J.Feng State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Due to native character of thermal expansion coefficient(CTE)mismatch between C_(f)/SiC and GH3536,achieving high strength joint was a huge challenge for C_(f)/SiC-GH3536 ***,a composite filler metal of Ag-Cu-Ti+Sc_(2)(WO_(4))_(3) was developed to join C_(f)/SiC and *** work introduced Sc_(2)(WO_(4))_(3) to Ag-Cu-Ti system as a negative thermal expansion(NTE)reinforcing phase to release joint residual ***_(2)(WO_(4))_(3) was evenly distributed in the brazing seam and reacted with Ti to form Ti_(3)O_(5) reaction *** results of finite element analysis showed that the residual stress of the joints was effectively released by introducing Sc_(2)(WO_(4))_(3) reinforcing phase,and the mises stress was decreased from447 to 401 *** maximum shear strength of the C_(f)/SiC-GH3536 joint brazed with Ag-Cu-Ti+6 vol%Sc_(2)(WO_(4))_(3) filler alloys was 64 Mpa,which was about 2.6 times higher than that of Ag-Cu-Ti *** results of this study provide a promising strategy for the introduction of new Sc_(2)(WO_(4))_(3) reinforcing phase in Ag-Cu-Ti system,and improve the reliability and feasibility of composite brazing alloy in brazing filed.

关键词： Negative thermal expansion Brazing Residual stress Composite brazing alloy CTE

Experimental and numerical analyses of nitrogen oxides formation in a high ammonia‑low hydrogen blend using a tangential swirl burner

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Carbon Neutrality 2022年第1期1卷 291-310页

作者： A.Alnasif S.Mashruk M.Kovaleva p.wang A.Valera-Medina College of physical Sciences and Engineering Queen’s BuildingCardiff UniversityCardiffWales CF243AAUK Engineering Technical College of Al-Najaf Al-Furat Al-Awsat Technical UniversityNajaf 31001Iraq Institute for Energy Research Jiangsu UniversityJiangsu 212013China

Ammonia has been considered as a novel fuel for decarbonization ***,emissions from combustion systems are still posing a ***,experimental and numerical simulations have been conducted to study the concentration of exhaust emissions(Nitric oxide“NO”,Nitrous oxide“N_(2)O”)from burning the ammonia/hydrogen(NH_(3)/H_(2))blend 85/15(vol%).The effects were measured at various thermal powers ranging 10 to 20 kW and with different Reynolds numbers from 20,000—40,*** experimental points were numerically investigated in the Ansys CHEMKIN-pro environment employing seven chemical kinetic mechanisms taken from the *** experiments have been undertaken at standard atmospheric *** experimental results showed that both NO and N_(2)O gradually increased when the Reynolds number increased from 20,000 to 40,*** with that,the concentration of NO emissions at the exhaust reported minimum level when the Re=20,000 due to lower reactivity radical formation,all that led to a deterioration of the flame ***,the integrated radical intensities of NO*,OH*,NH*,and NH_(2)*demonstrate an increasing trend as Re increased from 20,000 to 40,*** terms of thermal power,N_(2)O suffered an abrupt decrease when the thermal power increased up to 15 kW,while the opposite occurs for *** addition,the radicals intensity of OH*,NH*and NH_(2)*figures show an increase in their concentration when the thermal power increased up to 15 kW then decreased with increasing thermal intensity to reach 20 kW,reflecting into increased NO productions and decreased N_(2)O *** numerical analysis showed that Stagni,Bertolino,and Bowen Mei were the most accurate mechanisms as these give a good prediction for NO and N_(2)*** study also showed that the chemical reaction(HNO+O_(2)←→NO+HO_(2))is the main source of NO *** the chemical reaction(NH+NO←→N_(2)O+H)is responsible for the formation of N_(2)O by consuming NO and when there will

关键词： Ammonia N_(2)O NO Chemiluminescence Kinetic modeling

THE BEHAVIOUR OF Mn ATOMS IMpLANTED INTO Na^+- BETA- ALUMINA SINGLE CRYSTAL

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Nuclear Science and Techniques 1990年第3期1卷 137-142页

作者：姬成周 p.wang 单锦安郑东东 Institute of Low- Energy Nuclear physics Beijing Normal University Beijing 100875 China The Department of physics State University of New York at Albany Albany USA.

Upon heating, Mn atoms implanted into Na - beta- alumina diffuse inwards andoutwards with an activation energy of 0.96 eV, and substitute for Al3+ in the spinel layers of the crystal. For specimens annealed at 900 C, the optical absorption shows remarkable change in 190nm-400nm wavelength region. They fluoresce brightly green and a well- defined peak (at 525 nm) has been found in the radiative spectra.

关键词： Beta-alumina Diffusion Luminescence Ion implantation

Microstructure and mechanical properties of Al-12Si and Al-3.5Cu-1.5Mg-1Si bimetal fabricated by selective laser melting

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Journal of Materials Science & Technology 2020年第1期36卷 18-26页

作者： p.wang C.S.Lao Z.W.Chen Y.K.Liu H.wang H.Wendrock J.Eckert S.Scudino Additive Manufacturing Institute College of Mechatronics and Control EngineeringShenzhen UniversityNanhai Street 3688518060ShenzhenP.R.China Institute for Complex Materials IFW DresdenHelmholtzstraβe 20D-01069DresdenGermany Guangdong provincial Key Laboratory ofMicro/Nano Optomechatronics Engineering College of Mechatronics and Control EngineeringShenzhen University Nanhai Street 3688518060ShenzhenP.R.China Erich Schmid Institute of Materials Science Austrian Academy of SciencesJahnstraJie 12A-8700LeobenAustria Department of Materials Science Montanuniversitat LeobenJahnstraJSe 12A-8700LeobenAustria

An Al-12 Si/Al-3.5 Cu-1.5 Mg-1 Si bimetal with a good interface was successfully produced by selective laser melting(SLM).The SLM bimetal exhibits four successive zones along the building direction:an Al-12 Si zone,an interfacial zone,a texture-strengthening zone and an Al-Cu-Mg-Si *** interfacial zone(plays an increasing size of the cells composed of eutectic Al-Si and a discontinuous cellular microstructure,resulting in the lowest hardness of the four *** texturestrengthening zone(around 0.3 mm thick)shows a remarkable variation of the hardness andfiber *** backscatter diffraction analysis shows that the grains grow gradually from the interfacial zone to the Al-Cu-Mg-Si zone along the building ***,a strongfiber texture develops at the Al-Cu-Mg-Si side of the interfacial zone and disappears gradually along the building *** bimetal exhibits a room temperature yield strength of 267±10 Mpa and an ultimate tensile strength of 369±15 Mpa with elongation of 2.6±0.1%,revealing the potential of selective laser melting in manufacturing dissimilar materials.

关键词： Selective laser melting Aluminum alloys Bimetals Microstructure Mechanical properties

Conditioning of BpM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

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Chinese physics C 2014年第10期38卷 82-91页

作者：徐卫李京祎黄森林 W.Z.Wu H.Hao p.wang Y.K.Wu National Synchrotron Radiation Laboratory (NSRL) University of Science and Technology of China Dept.of physics Duke University and FEL labTriangle Universities Nuclear LaboratoryDurhamNC 27708-0308USA Institute of Heavy Ion physics Peking University

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers（FELs）, and the High Intensity Gamma-ray Source（HIGS）. It is operated with a beam current ranging from about1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and γ-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors（BpMs） are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BpM pickups associated with high single-bunch current degrades the performance of the BpM electronics, and can potentially damage the BpM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BpM electronics, and to make the BpMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BpM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

关键词： beam position monitor signal conditioning closed orbit feedback storage ring FEL

Contributions to the nucleon form factors from bubble and tadpole diagrams

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Chinese physics C 2023年第2期47卷 63-70页

作者：高正阳王平杨明炀 Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China School of physical Sciences University of Chinese Academy of SciencesBeijing 100049China

The nonlocal chiral effective theory is applied to investigate the electromagnetic and strange form factors of *** bubble and tadpole diagrams are included in the *** the contributions from bubble and tadpole diagrams,the obtained electromagnetic form factors are close to the results without these contributions as long as the low energy constants c_(1) and c_(2) are properly chosen,while the magnitudes of strange form factors become *** electromagnetic form factors are in good agreement with the experimental results,while the magnitudes of strange form factors are larger than the lattice data.

关键词： effective field theory nonlocal Lagrangian electromagnetic form factors strange form factors

A ptrLBD39-mediated transcriptional network regulates tension wood formation in populus trichocarpa

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plant Communications 2022年第1期3卷 85-99页

作者： Jing Yu Chenguang Zhou Danning Li Shuang Li Ying-Chung Jimmy Lin Jack p.wang Vincent L.Chiang Wei Li State Key Laboratory of Tree Genetics and Breeding Northeast Forestry UniversityHarbin 150040China Department of Life Sciences and Institute of plant Biology College of Life ScienceNational Taiwan UniversityTaipeiTaiwan 10617China Department of Forestry and Environmental Resources Forest Biotechnology GroupNorth Carolina State UniversityRaleighNC 27695USA

Tension wood(TW)is a specialized xylem tissue formed in angiosperm trees under gravitational stimulus or mechanical stresses(e.g.,bending).The genetic regulation that underlies this important mechanism remains poorly ***,we used laser capture microdissection of stem xylem cells coupled with full transcriptome RNA-sequencing to analyze TW formation in populus *** tree bending,ptrLBD39 was the most significantly induced transcription factor gene;it has a phylogenetically paired homolog,***-based knockout of ptrLBD39/22 severely inhibited TW formation,reducing cellulose and increasing lignin *** analyses of CRISpR-based ptrLBD39/22 double mutants showed that these two genes regulate a set of TW-related *** immunoprecipitation sequencing(ChIp-seq)was used to identify direct targets of *** integrated transcriptomic analyses and ChIp-seq assays to construct a transcriptional regulatory network(TRN)mediated by *** this TRN,ptrLBD39 directly regulates 26 novel TW-responsive transcription factor *** work suggests that ptrLBD39 and ptrLBD22 specifically control TW formation by mediating a TW-specific TRN in populus.

关键词： tension wood cellulose lignin transcriptional regulatory network transcriptomics chromatin immunoprecipitation sequencing

N-polar InGaN/GaN nanowires: overcoming the efficiency cliff of red-emitting micro-LEDs

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photonics Research 2022年第4期10卷 1107-1116页

作者： A.pandey Y.Malhotra p.wang K.Sun X.Liu Z.Mi Department of Electrical Engineering and Computer Science University of MichiganAnn ArborMichigan 48109USA Department of Materials Science and Engineering University of MichiganAnn ArborMichigan 48109USA

A high efficiency, high brightness, and robust micro or sub-microscale red light emitting diode(LED) is an essential, yet missing, component of the emerging virtual reality and future ultrahigh resolution mobile *** report, for the first time, to our knowledge, the demonstration of an N-polar In GaN/GaN nanowire submicroscale LED emitting in the red spectrum that can overcome the efficiency cliff of conventional red-emitting micro-LEDs. We show that the emission wavelengths of N-polar In GaN/GaN nanowires can be progressively shifted from yellow to orange and red, which is difficult to achieve for conventional In GaN quantum wells or Ga-polar nanowires. Significantly, the optical emission intensity can be enhanced by more than one order of magnitude by employing an in situ annealing process of the In GaN active region, suggesting significantly reduced defect formation. LEDs with lateral dimensions as small as ~0.75 μm, consisting of approximately five nanowires, were fabricated and characterized, which are the smallest red-emitting LEDs ever reported, to our knowledge. A maximum external quantum efficiency ~1.2% was measured, which is comparable to previously reported conventional quantum well micro-LEDs operating in this wavelength range, while our device sizes are nearly three to five orders of magnitude smaller in surface area.

关键词： InGaN/GaN emitting polar

工程因素对页岩气产量的影响——以北美Haynesville页岩气藏为例

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天然气工业 2012年第4期32卷 54-59,123页

作者：李庆辉陈勉 Fred p.wang 金衍李志猛中国石油大学(北京)石油工程学院 University of Texas at Austin

我国页岩气开发尚处于前期探索阶段,分析国外成功的开发案例具有重要的借鉴作用和参考价值。在对北美Haynesville页岩气藏生产数据进行统计和分析的基础上,总结了工程因素对该页岩气藏开发的影响规律。结论认为:页岩气井水平段长度、压... 详细信息

我国页岩气开发尚处于前期探索阶段,分析国外成功的开发案例具有重要的借鉴作用和参考价值。在对北美Haynesville页岩气藏生产数据进行统计和分析的基础上,总结了工程因素对该页岩气藏开发的影响规律。结论认为:页岩气井水平段长度、压裂级数、加砂量、油嘴尺寸、井底压力和是否采取重复压裂施工对累积产量有显著影响;水平段长度在1 500～1 650m之间、压裂级数12～17级、加砂量1 500～3 000t、油嘴尺寸8～9mm为该地区常用且效果较好的设计方案;井底压力高的区域页岩气产量相应较高,这与井底超压改善页岩脆性、优化压裂效果有关;重复压裂能够显著提高页岩气总产量,作业时机的选择与增产效果关系密切。

关键词：页岩气工程因素生产能力水平井压裂(岩石) 规模重复压裂增产效果