检索结果-南通市图书馆

Resistive field generation in intense proton beam interaction with solid targets

作者： (美)h.f.彼得斯

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第1期9卷 35-43页

作者： W.Q.Wang J.J.honrubia Y.Yin X.h.Yang f.Q.Shao Department of Physics National University of Defense TechnologyHunanChina ETSI Aeronáutica y del Espacio Universidad Politécnica de MadridMadridSpain Department of Nuclear Science and Technology National University of Defense TechnologyHunanChina

The Brown-Preston-Singleton(BPS)stopping power model is added to our previously developed hybrid code to model ion beam-plasma *** simulations show that both resistive field and ion scattering effects are important for proton beam transport in a solid target,in which they compete with each *** the target is not completely ionized,the self-generated resistive field effect dominates over the ion scattering ***,when the target is completely ionized,this situation is ***,it is found that Ohmic heating is important for higher current densities and materials with high *** energy fraction deposited as Ohmic heating can be as high as 20%-30%.Typical ion divergences with half-angles of about 5°-10°will modify the proton energy deposition substantially and should be taken into account.

关键词： interaction beam intense

近红外激发PLNPs/UCNPs纳米复合材料的制备及其性能研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

近红外激发PLNPs/UCNPs纳米复合材料的制备及其性能研究

作者：鲁克曼·喀斯木（Lukman Kasim）喀什大学

学位级别：硕士

研究人员在新型多功能纳米材料的研发上付出了诸多努力,并将其广泛应用于生物医学领域。其中,长余辉发光材料和上转换发光材料在生物成像、生物传感和癌症治疗等领域的发展,具有潜在应用前景。但是,长余辉发光材料和上转换发光材料的开... 详细信息

研究人员在新型多功能纳米材料的研发上付出了诸多努力,并将其广泛应用于生物医学领域。其中,长余辉发光材料和上转换发光材料在生物成像、生物传感和癌症治疗等领域的发展,具有潜在应用前景。但是,长余辉发光材料和上转换发光材料的开发仍然面临着一些挑战。部分长余辉发光材料中能量的耗尽可以被光激励持续发光策略恢复,但大部分长余辉发光材料充电效率差,发射强度和穿透深度仍然受到限制,满足不了在体内重复激发以便用于长期成像应用的需求;上转换发光材料内部的非辐射能量损失和其他损耗机制的存在,导致发光效率较低,并且发光时间有限。基于以上问题,可以通过发射波长在近红外第二（NIR-II）生物窗口的长余辉发光材料来解决长余辉发光穿透深度受到限制的问题;通过将长余辉发光材料和上转换发光材料的结合来解决长期成像应用的需求。在第一项工作中,我们采用水热合成法,制备了发射波长位于NIR-II生物窗口的Ni2+掺杂镓酸锌Zn1+2xGa2-2xO4:Nix2+（ZGO:Ni）长余辉发光材料,ZGO:Ni在1000～1500nm之间出现宽带发射峰。系统地研究了不同煅烧温度和p h值以及Ni2+不同掺杂比例对ZGO:Ni发光特性的影响。采用XRD、TEM、EDS、荧光光谱仪进行测试,对制备的ZGO:Ni进行了表征,并研究了其光致发光性能、余辉发光性能和发光机理。结果显示,通过优化煅烧温度和p h值以及Ni2+的掺杂量,确定了当ZGO:Ni的煅烧温度为1000℃、p h值为8、Ni2+的掺杂量1%时发光性能最佳,发射波长位于1290 nm处。在第二项工作中,我们构建了Zn Ga2O4:Ni2+/Na Er f4:Yb3+,Mn2+（ZGO:Ni/UCNPs）上转换长余辉纳米复合材料。我们采用水热合成法,制备了激发源为980 nm激光、发射波长在600-700 nm范围内的Na Er f4:Yb3+,Mn2+上转换发光材料,基于荧光共振能量转移体系,通过共价键将Zn Ga2O4:Ni2+与Na Er f4:Yb3+,Mn2+结合。所得到的复合材料用980 nm激光激活后,在1290 nm处呈现持续发光。这是由于980 nm激光激发后,Na Er f4:Yb3+,Mn2+的发射光谱与Zn Ga2O4:Ni2+的激发光谱有良好的重叠,使得Na Er f4:Yb3+,Mn2+中的Er3+和Zn Ga2O4:Ni2+中的Ni2+之间发生荧光共振能量转移。ZGO:Ni/UCNPs上转换长余辉纳米复合材料的构建,解决了光激励持续发光策略不能满足体内重复激发以供长期成像应用需求的问题。此外,因为复合材料的激发（980nm）和发射（1290 nm）波长位于生物NIR-I、NIR-II生物窗口内,适合用于深层组织的生物成像,因此,该复合材料在体内生物成像方面有巨大的应用潜力。

关键词：长余辉发光上转换发光上转换长余辉发光 NIR-Ⅱ生物窗口

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

煤样的瓦斯解吸过程

煤炭工程师 1992年第2期 52-56页

作者： h.f.雅纳斯于策西德

认识吸附在煤体中的瓦斯释放规律,对于预测原煤的瓦斯涌出量具有重要意义。针对提出的特殊问题采用了可计算生产过程(如煤的开采、运输、贮存过程)中的瓦斯解吸速度的方法。涌出的瓦斯主要由两部分组成,一是存在于煤体内部空隙中的游... 详细信息

认识吸附在煤体中的瓦斯释放规律,对于预测原煤的瓦斯涌出量具有重要意义。针对提出的特殊问题采用了可计算生产过程(如煤的开采、运输、贮存过程)中的瓦斯解吸速度的方法。涌出的瓦斯主要由两部分组成,一是存在于煤体内部空隙中的游离瓦斯,二是附着在煤的内表面的吸附瓦斯。游离瓦斯是在煤卸压以后由于吸附平衡破坏而直接释放出来。因为它的体积很小,所以在计算原煤瓦斯涌出量时可以忽略不计。

关键词：煤样瓦斯解吸

维普期刊数据库

A Comprehensive Review on Charging Topologies and Power Electronic Converter Solutions for Electric Vehicles

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 675-694页

作者： Abdelfatah Ali hossam h.h.Mousa Mostafa f.Shaaban Maher A.Azzouz Ahmed S.A.Awad the Department of Electrical Engineering American University of Sharjah26666 SharjahUnited Arab Emirates the Department of Electrical Engineering South Valley University83523 QenaEgypt the Department of Electrical and Computer Engineering University of WindsorWindsorON N9B 3P4 Canada Electrical Engineering Department Qatar UniversityDoha 2713Qatar Department of Electrical and Computer Engineering Sultan Qaboos UniversityMuscat123Oman

Electric vehicles(EVs)are becoming more popular worldwide due to environmental concerns,fuel security,and price *** performance of EVs relies on the energy stored in their batteries,which can be charged using either AC(slow)or DC(fast)***,EVs can also be used as mobile power storage devices using vehicle-to-grid(V2G)*** electronic converters(PECs)have a constructive role in EV applications,both in charging EVs and in ***,this paper comprehensively investigates the state of the art of EV charging topologies and PEC solutions for EV *** examines PECs from the point of view of their classifications,configurations,control approaches,and future research prospects and their impacts on power *** can be classified into various topologies:DC-DC converters,AC-DC converters,DC-AC converters,and AC-AC *** address the limitations of traditional DC-DC converters such as switching losses,size,and high-electromagnetic interference(EMI),resonant converters and multiport converters are being used in high-voltage EV ***,power-train converters have been modified for high-efficiency and reliability in EV *** paper offers an overview of charging topologies,PECs,challenges with solutions,and future trends in the field of the EV charging station applications.

关键词： Charging station charging topology electric vehicle power electronic converter vehicle-to-grid

维普期刊数据库

Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： Y.h.Zhang h.Li Z.W.Yang X.Liu Q.f.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of high-Performance Precision forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

Connections Between Induction Generator Effect and Open-loop Modal Proximity to Cause Sub-synchronous Oscillations in Series-compensated Power System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第3期10卷 963-973页

作者： Wenjuan Du Yang Wang h.f.Wang Tao Zhao Tim Littler College of Electrical Engineering Sichuan UniversityChengduChina School of Electrical Engineering the Queen’s University of BelfastBelfastUK IEEE

The induction generator effect(IGE)and the openloop modal proximity(OLMP)are two different reasons why subsynchronous oscillations(SSOs)in a series-compensated power system(SCPS)may *** IGE attributes the growing SSOs to negative resistance,while the OLMP explains the SSO mechanism from the standpoint of modal *** this paper,we investigate the connections between the IGE and the OLMP through equivalent RLC circuit and open-loop modal *** investigation is conducted for two types of seriescompensated power systems where either a synchronous generator or a DfIG is connected at the sending *** investigation reveals the conditions,in which the IGE and the OLMP may jointly cause the growing SSOs,i.e.,both the IGE and the OLMP can explain why the growing SSOs ***,the investigation indicates that the IGE and the OLMP may be totally irrelevant and lead to growing SSOs *** implies that it is possible that in a SCPS,the growing SSOs are only due to the IGE,and the OLMP is non-existent,and vice ***,when the growing SSOs occurs in a SCPS,examination based on both the IGE and the OLMP should be carefully conducted in order to find if the oscillatory instability is due to the IGE,or the OLMP,or both of them.

关键词： Induction generator effect open-loop modal proximity series compensation sub-synchronous oscillations

Spalling characteristics of high-temperature treated granitic rock at different strain rates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1280-1288页

作者： L.f.fan Q.h.Yang X.L.Du The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing100124China

The dynamic spalling characteristics of rock are important for stability analysis in rock *** paper presented an experimental investigation on the dynamic spalling characteristics of granite with different temperatures and strain rates.A series of dynamic spalling tests with different impact velocities were conducted on thermally treated granite at different *** dynamic spalling strengths of granite with different temperatures and strain rates were determined.A model was proposed to correlate the dynamic spalling strength of granite,high temperature and strain *** results show that the spalling strength of granite decreases with increasing ***,the spalling strength of granite with a higher strain rate is larger than that with a lower strain *** proposed model can describe the relationship among dynamic spalling strength of granite,high temperature and strain rate.

关键词： Dynamic spalling characteristics high temperature Strain rate Dynamic loading Granite

创新科学结构图谱对中美基础研究影响技术创新的揭示

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国科学院院刊 2024年第3期39卷 588-600页

作者：陈挺冷伏海李国鹏王小梅中国科学院科技战略咨询研究院北京100190

文章利用科学结构图谱分析方法首次绘制了创新科学结构图谱,以被专利引用的基本科学指标数据库(ESI)高被引论文为数据基础,揭示了世界前沿基础研究对技术创新发展的影响情况;发现其中对技术创新发展起到推动作用的热点方向,并对比中美... 详细信息

文章利用科学结构图谱分析方法首次绘制了创新科学结构图谱,以被专利引用的基本科学指标数据库(ESI)高被引论文为数据基础,揭示了世界前沿基础研究对技术创新发展的影响情况;发现其中对技术创新发展起到推动作用的热点方向,并对比中美两国在这些热点方向上的表现,为科学决策提供有效的数据支撑。分析发现:被专利引用较高的论文主要集中在新生物技术与生物医疗技术、新兴信息技术、能源与材料这些可能引发颠覆性技术创新的基础研究领域;中国被专利引用的高被引论文增势明显,5年累计增长超过60%,但数量还是不到美国的50%;中国在不少与技术创新关联紧密的热点研究方向中的论文数量高于美国,但被专利引用的论文数量却通常低于美国;美国影响技术创新的基础研究内容更多的是引领产业变革方面的研发活动,并且有大量企业参与。

关键词：创新图谱专利引用论文基础研究高被引论文技术创新

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

将扁材和长材生产设备费用减小到最低限度

钢铁 1989年第3期24卷 W001-W014页

作者： h.f.马丁陈钰鹏 SMS施勒曼-西马克股份公司

从各个生产部门中可以明显地看出,要想减少设备投资费用和生产费用,只有改变生产工艺才能取得有效成绩。有什么办法可以达到上述目的?可用热轧宽带轧机、冷轧机、型材轧机和管材轧机的例子加以说明。

关键词：轧钢设备轧制扁材长材

维普期刊数据库