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Anneal-free ultra-low loss silicon nitride integrated photonics

light(Science & Applications) 2024年第8期13卷 1565-1577页

作者： Debapam Bose Mark W.Harrington Andrei Isichenko kaikai l.u Jiawei Wang Nitesh Chauhan Zachary l.Newman Daniel J.Blumenthal Department of Electrical and Computer Engineering University of California Santa BarbaraSanta BarbaraCA 93106USA Octave Photonics LouisvilleCO 80027USA

Heterogeneous and monolithic integration of the versatile low-loss silicon nitride platform with low-temperature materials such as silicon electronics and photonics,III–V compound semiconductors,lithium niobate,organics,and glasses has been inhibited by the need for high-temperature annealing as well as the need for different process flows for thin and thick *** techniques are needed to maintain the state-of-the-art losses,nonlinear properties,and CMOS-compatible processes while enabling this next generation of 3D silicon nitride *** report a significant advance in silicon nitride integrated photonics,demonstrating the lowest losses to date for an anneal-free process at a maximum temperature 250℃,with the same deuterated silane based fabrication flow,for nitride and oxide,for an order of magnitude range in nitride thickness without requiring stress mitigation or *** report record low anneal-free losses for both nitride core and oxide cladding,enabling 1.77 dBm-1 loss and 14.9 million Q for 80 nm nitride core waveguides,more than half an order magnitude lower loss than previously reported sub 300℃ *** 800 nm-thick nitride,we achieve as good as 8.66 dBm-1 loss and 4.03 million Q,the highest reported Q for a low temperature processed resonator with equivalent device area,with a median of loss and Q of 13.9 dBm-1 and 2.59 million each *** demonstrate laser stabilization with over 4 orders of magnitude frequency noise reduction using a thin nitride reference cavity,and using a thick nitride micro-resonator we demonstrate OPO,over two octave supercontinuum generation,and four-wave mixing and parametric gain with the lowest reported optical parametric oscillation threshold per unit resonator *** results represent a significant step towards a uniform ultra-low loss silicon nitride homogeneous and heterogeneous platform for both thin and thick waveguides capable of linear and nonlinear photonic circuits and integrat

关键词： resonator thick free

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Enhancing Strength-Ductility Synergy of CoCrNi-Based Medium-Entropy Alloy Through Coherent l1_(2)Nanoprecipitates and Grain Boundary Precipitates

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Acta Metal.urgica Sinica(English letters) 2024年第1期37卷 78-88页

作者： leilei li kaikai Song Qingwei Gao Changshan Zhou Xiaoming l.u Yaocen Wang Xiaojun Bai Chongde Cao School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an710016China Weihai Research Institute of Industrial Technology Shandong UniversityWeihai264209China Research and Development Institute of Northwestern Polytechnical University in ShenzhenShenzhen518057China

The l1_(2)-strengthened Co_(34)Cr_(32)Ni_(27)Al_(4)Ti_(3)medium-entropy alloy(MEA)with precipitations of grain boundaries has been developed through selective laser melting(SlM)followed by cold rolling and annealing,exhibiting excellent strength-ductility *** as-printed alloy exhibits low yield strength(YS)of~384 MPa,ultimate tensile strength(uTS)of~453 MPa,and uniform elongation(uE)of 1.5%due to the existence of the SlM-induced *** cold rolling and annealing,the YS,uTS,and uE are significantly increased to~739 MPa,~1230 MPa,and~47%,*** enhancement primarily originates from the refined grain structure induced by cold rolling and *** presence of coherent sphericalγ'precipitates(l1_(2)phases)and Al/Ti-rich precipitates at the grain boundaries,coupled with increased lattice defects such as dislocations,stacking faults,and ultrafine deformation twins,further contribute to the property’s *** study highlights the potential of SlM in producing high-strength and ductile MEA with coherent l1_(2)nanoprecipitates,which can be further optimized through subsequent rolling and annealing *** findings offer valuable insights for the development of high-performance alloys for future engineering applications.

关键词： Medium-entropy alloy Selective laser melting Precipitation Strength Ductility

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In search of a pan-coronavirus vaccine:next-generation vaccine design and immune mechanisms

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Cel.ular & Molecular Immunology 2024年第2期21卷 103-118页

作者： S.Cankat M.u.Demael l.Swadling Division of Infection and Immunity Institute of Immunity and TransplantationUniversity College LondonPears BuildingLondon NW32PPUK

Members of the coronaviridae family are endemic to human populations and have caused several epidemics and pandemics in recent *** this review,we will discuss the feasibility of and progress toward the ultimate goal of creating a pan-coronavirus vaccine that can protect against infection and disease by all members of the coronavirus *** will detail the unmet clinical need associated with the continued transmission of SARS-CoV-2,MERS-CoV and the four seasonal coronaviruses(HCoV-OC43,Nl63,HKu1 and 229E)in humans and the potential for future zoonotic *** will highlight how first-generation SARS-CoV-2 vaccines and natural history studies have greatly increased our understanding of effective antiviral immunity to coronaviruses and have informed next-generation vaccine *** will then consider the ideal properties of a pan-coronavirus vaccine and propose a blueprint for the type of immunity that may offer ***,we will describe a subset of the diverse technologies and novel approaches being pursued with the goal of developing broadly or universally protective vaccines for coronaviruses.

关键词： Vaccine Coronavirus Cross-reactive immunity Cross-protection universal

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Stabilizing semi-transparent perovskite solar cells with a polymer composite hole transport layer

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Nano Research 2024年第3期17卷 1500-1507页

作者： Yongbin Jin Huiping Feng Zheng Fang l.u Yang kaikai l.u Bingru Deng Jingfu Chen Xueling Chen Yawen Zhong Jinxin Yang Chengbo Tian liqiang Xie Zhanhua Wei Xiamen Key laboratory of Optoelectronic Materials and Advanced Manufacturing Institute of Luminescent Materials and Information DisplaysCollege of Materials Science and EngineeringHuaqiao UniversityXiamen 361021China

Semi-transparent perovskite solar cells(ST-PSCs)have broad applications in building integrated ***,the stability of ST-PSCs needs to be improved,especially in n-i-p ST-PSCs since the doped 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene(Spiro-OMeTAD)is unstable at elevated temperatures and high *** this work,aπ-conjugated polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)](PBDB-T)is selected to form a polymer composite hole transport layer(HTl)with *** sul.ur atom of the thiophene unit and the carbonyl group of the polymer interact with the undercoordinated Pb2+at the perovskite surface,which stabilizes the perovskite/HTl interface and passivates the interfacial *** incorporation of the polymer also increases the glass transition temperature and the moisture resistance of *** a result,we obtain ST-PSCs with a champion efficiency of 13.71%and an average visible light transmittance of 36.04%.Therefore,a high light utilization efficiency of 4.94%can be ***,the encapsulated device can maintain 84%of the initial efficiency after 751 h under continuous one-sun il.umination(at 30%relative humidity)at the open circuit and the unencapsulated device can maintain 80%of the initial efficiency after maximum power tracking for more than 1250 h under continuous one-sun il.umination.

关键词： semi-transparent solar cells π-conjugated polymer composite hole transport layer building integrated photovoltaics

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Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

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Chinese Physics B 2024年第2期33卷 108-114页

作者： u.S.Mahabaleshwar G.P.Vanitha l.M.Pérez Emad H.Aly I.Pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked *** the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching ***,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O ***,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow analytical solution suction/injection

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重载机车102型钩缓装置动态模拟方法与动力学性能研究

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振动与冲击 2024年第2期43卷 12-21,59页

作者：张志超吕凯凯储高峰齐红瑞汪方文中国铁道科学研究院集团有限公司机车车辆研究所北京100081 中车大同电力机车有限公司技术中心山西大同037038

该研究结合试验数据提出了重载机车102型车钩缓冲装置受压动态响应的模拟方法,并研究了该机车及钩缓装置在双机重联牵引万吨列车编组下的动力学性能。基于102型钩缓装置结构特性与受压稳钩机理,采用加权离散方法将缓冲器简化为具有相同... 详细信息

该研究结合试验数据提出了重载机车102型车钩缓冲装置受压动态响应的模拟方法,并研究了该机车及钩缓装置在双机重联牵引万吨列车编组下的动力学性能。基于102型钩缓装置结构特性与受压稳钩机理,采用加权离散方法将缓冲器简化为具有相同迟滞特性的多个阻抗力元,并引入剪切刚度来考虑其相互之间的剪切效应,提出了能够准确模拟钩肩止挡和缓冲器偏压特性的102型钩缓装置动力学建模方法;进而借助子结构方法搭建了“主控机车+重联机车+货车车辆+虚拟货列”的双机重联牵引万吨列车动力学模型,其中四节机车、货车车辆之间采用钩缓装置子结构连接;通过试验数据对比修正了钩缓装置模型中离散阻抗力元间的剪切刚度,并验证了所建列车动力学模型的正确性;计算分析了线路条件、结构参数、机车电制力等对系统动力学响应和运行安全性的影响规律。结果表明:重载机车在小半径曲线上施加大电制力容易引起异常增大的轮轴横向力,危及行车安全;随着车钩最大自由转角的增大,车钩偏转角和机车运行安全性指标均呈逐渐增大趋势;机车二系悬挂横向刚度增大有助于提高机车自身的受压稳定性和减小车钩偏转角,但过大横向刚度又会增大轮轨横向动态作用。

关键词：重载机车 102型钩缓装置重载适应性受压稳定性机车电制力

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Promotion of structural plasticity in area V2 of visual cortex prevents against object recognition memory deficits in aging and Alzheimer's disease rodents

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Neural Regeneration Research 2024年第8期19卷 1835-1841页

作者： Irene Navarro-lobato Mariam Masmudi-Martín Manuel F.lópez-Aranda Juan F.lópez-Téllez Gloria Delgado Pablo Granados-Durán Celia Gaona-Romero Marta Carretero-Rey Sinforiano Posadas María E.Quiros-Ortega Zafar u.Khan laboratory of Neurobiology Centro de Investigaciones Médico Sanitarias(CIMES)University of MalagaMalagaSpain Department of Medicine Faculty of MedicineUniversity of MalagaMalagaSpain Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas(CIBERNED) Institute of Health Carlos IIIMadridSpain the Donders Institute for Brain Cognition and Behaviour Radboud UniversityNijmegenThe Netherlands the Brain Metastasis Group National Cancer Research Centre(CNIO)MadridSpain the Department of Neurobiology University of California-Los AngelesLos AngelesCAUSA

Memory deficit,which is often associated with aging and many psychiatric,neurological,and neurodegenerative diseases,has been a challenging issue for *** till now,all potential drug candidates have failed to produce satisfa ctory ***,in the search for a solution,we found that a treatment with the gene corresponding to the RGS14414protein in visual area V2,a brain area connected with brain circuits of the ventral stream and the medial temporal lobe,which is crucial for object recognition memory(ORM),can induce enhancement of *** this study,we demonstrated that the same treatment with RGS14414in visual area V2,which is relatively unaffected in neurodegenerative diseases such as Alzheimer s disease,produced longlasting enhancement of ORM in young animals and prevent ORM deficits in rodent models of aging and Alzheimer’s ***,we found that the prevention of memory deficits was mediated through the upregulation of neuronal arbo rization and spine density,as well as an increase in brain-derived neurotrophic factor(BDNF).A knockdown of BDNF gene in RGS14414-treated aging rats and Alzheimer s disease model mice caused complete loss in the upregulation of neuronal structural plasticity and in the prevention of ORM *** findings suggest that BDNF-mediated neuronal structural plasticity in area V2 is crucial in the prevention of memory deficits in RGS14414-treated rodent models of aging and Alzheimer’s ***,our findings of RGS14414gene-mediated activation of neuronal circuits in visual area V2 have therapeutic relevance in the treatment of memory deficits.

关键词： behavioral performance brain-derived neurotrophic factor cognitive dysfunction episodic memory memory circuit activation memory deficits memory enhancement object recognition memory prevention of memory loss regulator of G protein signaling

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Mechanics and physics under supergravity conditions

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Acta Mechanica Sinica 2024年第6期40卷 1-2页

作者： Chaofeng lü Chao Sun Shengqiang Cai Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China New Cornerstone Science laboratory Center for Combustion EnergyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Mechanical and Aerospace Engineering University of CaliforniaSan DiegoLa Jolla CA 92093USA

"Supergravity"refers to the conditions where the effective gravity is greater than that of *** conditions are generally relevant to stellar evolution,geophysical movement,astrophysical flows,and *** also frequently occur in various engineering scenarios involving acceleration,such as the l.unch of space shuttles,operation of rotor engines,impacts and explosions,chemical separation processes,and overloaded testing *** is already demonstrated in physiological experiments that living organisms of animals or plants could be damaged,either temporarily or permanently,when subjected to *** create supergravity conditions for scientific research on the Earth,centrifugal equipment or rapidly rotating devices are omnipresent in various fields,such as aerospace engineering,geophysical science,chemical and biomedical engineering,nuclear engineering,rotating flows,and physical modeling tests.

关键词： geophysical Earth stellar

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毛乌素沙地固碳功能菌群落随生物结皮发育阶段的演变特征

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生态学报 2024年第3期44卷 1177-1190页

作者：李凯凯张丙昌赵康张雅丽刘燕晋山西师范大学地理科学学院太原030031 山西师范大学生命科学学院太原030031 山西师范大学黄河中游生态环境研究中心太原030031

生物结皮是干旱区生态系统光合固碳的重要贡献者,固碳功能菌是生物结皮碳固定过程中的关键功能群,而毛乌素沙地生物结皮有关固碳功能菌群落多样性的研究未见详细报道。通过qPCR和高通量测序,研究了毛乌素沙地固碳功能菌基因丰度、群落... 详细信息

生物结皮是干旱区生态系统光合固碳的重要贡献者,固碳功能菌是生物结皮碳固定过程中的关键功能群,而毛乌素沙地生物结皮有关固碳功能菌群落多样性的研究未见详细报道。通过qPCR和高通量测序,研究了毛乌素沙地固碳功能菌基因丰度、群落多样性在生物结皮发育过程中的演变规律及其关键环境因子。结果表明,form IAB、IC和ID的基因丰度均随生物结皮发育呈升高趋势,在地衣结皮最高,在藓结皮又明显降低;form IAB的Chao1和form IC的Shannon指数随生物结皮演替呈显著上升趋势,而form IC和ID的Chao1则在藻结皮达到峰值。物种组成上,IAB型固碳功能菌以蓝藻门的颤藻目占优势,其相对丰度在藻结皮最高,随生物结皮演替逐渐降低;IC型固碳功能菌在裸沙中以土壤红杆菌目为主,而在三种生物结皮中以生丝微菌目、亚硝化单胞菌目和红螺菌目占优势;ID型固碳菌则以硅藻门的舟形藻目占优势,其丰度在裸沙中最高。IAB和IC型固碳功能菌群落结构在藻结皮和地衣结皮类似,而与裸沙和藓结皮差异显著,裸沙与藓结皮亦具显著差异。生物结皮演替过程中生物类群和土壤理化特征的改变为固碳功能菌提供了不同的生态位,土壤总有机碳、全氮、铵态氮、全磷、速效磷和pH对固碳功能菌群落进行综合调控,通过对固碳功能菌的筛选作用,最终改变固碳功能菌群落组成和结构。为深入理解荒漠生态系统生物结皮的光合固碳功能的微生物学机制提供了理论支撑。

关键词：生物结皮固碳功能菌群落多样性环境因素毛乌素沙地

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原位产过氧化氢光芬顿体系g-C_(3)N_(4)/CQDs/Fe^(2+)对土霉素的降解:机制、降解路径和毒性变化分析

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复合材料学报 2024年第5期41卷 2520-2533页

作者：石建惠石家汀蒲凯凯赵婷太原理工大学环境科学与工程学院山西030024

芬顿反应是一种通过Fe2+催化H2O2分解生成羟基自由基(·OH)的氧化工艺,因其·OH生成速率快和操作简单等优点被广泛应用于废水中有机污染物的降解,然而存在需要外部加入H2O2和pH适用范围窄的缺陷限制其进一步应用。为解决以上问题,通过外... 详细信息

芬顿反应是一种通过Fe2+催化H2O2分解生成羟基自由基(·OH)的氧化工艺,因其·OH生成速率快和操作简单等优点被广泛应用于废水中有机污染物的降解,然而存在需要外部加入H2O2和pH适用范围窄的缺陷限制其进一步应用。为解决以上问题,通过外加Fe2+活化复合光催化剂石墨相氮化碳/碳量子点(gC3N4/CQDs)原位生成的H2O2,构建了g-C3N4/CQDs/Fe2+光芬顿体系,避免了H2O2在储存和运输过程中的潜在风险,并扩宽了反应的pH值范围。该体系对土霉素(OTC)的降解表现出优异的活性,在g-C3N4/CQDs投加量为120 mg,OTC初始浓度为20 mg·l^(-1),Fe^(2+)投加量为0.36 mmol·l^(-1),OTC的初始pH为7时,其降解效率高达97%。基于自由基捕获、·OH的生成变化测定及与H2O2生成过程的对比等实验,证明g-C_(3)N_(4)/CQDs/Fe^(2+)光芬顿降解OTC优异的活性,主要来源于Fe^(2+)活化原位H_(2)O_(2)产生的·OH活性物种。进一步地,OTC降解的中间产物也通过质谱联用仪检测分析,并推断出OTC被降解的可能路径。此外,通过测量光密度(OD_(600))值获得细菌的生长曲线,结果表明随着g-C_(3)N_(4)/CQDs/Fe^(2+)降解OTC的进行,其反应溶液的毒性是逐渐减小的。最后,与外加H_(2)O_(2)传统芬顿体系降解OTC进行了对比分析,结果表明该光芬顿体系基本能够达到传统芬顿降解OTC的效果,且不受pH值范围的限制,为改善芬顿反应在实际废水处理中的应用提供了新的思路。

关键词：光芬顿光催化原位产过氧化氢土霉素降解路径毒性分析

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