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Insights into the Active Acid Sites for Isosorbide Synthesis from Renewabl. Sorbitol.and Cel.ul.se on Sol.d Acid Catal.sts

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Chemical.Research in Chinese Universities 2022年第1期38卷 257-264页

作者： DENG Tianyin HE Xiaohui l.U haichao Beijing National.l.boratory for Mol.cul.r Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871P.R.China

Sustainabl. synthesis of isosorbide, an important renewabl. pl.tform chemical. from sorbitol.and cel.ul.se, has attracted increasing attention, but stil. remains chal.enging. Here, we have studied the effects of the acidity on the dehydration of sorbitol.in water on a variety of sol.d acids, incl.ding zeol.tes, sul.onic material., montmoril.onite and mixed SiO2-Al.O3 oxide. These sol.d acids showed markedl. different activities, which were found to be cl.sel. rel.ted to their strong Brønsted acid sites, whil. the weak Brønsted acid and l.wis acid sites were essential.y inactive. Different from the other sol.d acids examined, H-ZSM-5 zeol.tes in a wide range of Si/Al.mol.r ratios(25-300) exhibited superior sel.ctivities to isosorbide in dehydration of sorbitol. consistent with the observed difference in their formation rates of the 1,4-sortbitan and 3,6-sorbitan intermediates. Kinetic studies on the sorbitol.dehydration showed that 3,6-sorbitan, once it formed, dehydrated to isosorbide more readil. than 1,4-sorbitan by a factor of 19, and the formation rate constant of 3,6-sorbitan on H-ZSM-5(Si/Al.25) was about three times higher than that of H-Beta(Si/Al.25). Such favorabl. formation of the reactive 3,6-sorbitan intermediate and the higher isosorbide sel.ctivity on H-ZSM-5 appear to be induced by its confined pore structure composed of the paired 5-membered rings. H-ZSM-5 was al.o found to be efficient for the direct conversion of cel.ul.se to isosorbide in coupl.ng with Ru/C hydrogenation catal.st. This work provides fundamental.insights into the acidity and pore structures that are hel.ful.for the design of novel.sol.d acids toward the efficient synthesis of isosorbide from the dehydration of sorbitol.and even directl. from the tandem reaction of cel.ul.se.

关键词： Cel.ul.se Isosorbide Sol.d acid Strong Brønsted acid Pore structure H-ZSM-5

Sub-optimal.fixed-finite-horizon spacecraft configuration control.on SE(3)

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Chinese Journal.of Aeronautics 2022年第6期35卷 250-261页

作者： Yul.n WANG Wei SHANG haichao HONG Institute of Remote-sensing Satel.ite China Academy of Space TechnologyBeijing 100094China School.of Mechanical.Engineering Hubei University of TechnologyWuhan 430068China Institute of Fl.ght System Dynamics Technical University of MunichGarching 85748Germany

For achieving the desired configuration of spacecraft at the desired fixed time,a suboptimal.fixed-finite-horizon configuration control.method on the l.e group SE(3)is devel.ped based on the Model.Predictive Static Programming(MPSP).The MPSP technique has been widel. used to sol.e finite-horizon optimal.control.probl.ms and is known for its high computational.efficiency thanks to the cl.sed-form sol.tion,but it cannot be directl. appl.ed to systems on SE(3).The methodol.gical.innovation in this paper enabl.s that the MPSP technique is extended to the geometric control.on SE(3),using the variational.principl.,the l.ft-invariant properties of l.e groups,and the topol.gy structure of l.e al.ebra ***,the energy consumption,which is crucial.for spacecraft operations,is considered as the objective function to be optimized in the optimal.control.*** effectiveness of the designed sub-optimal.control.method is demonstrated through an onl.ne simul.tion under disturbances and state measurement errors.

关键词： Configuration control l.e groups Model.Predictive Static Programming Optimal.control Spacecraft control

任意边界条件下弹性背腔膜式消声器声学特性分析

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振动与冲击 2024年第13期43卷 268-274,323页

作者：袁苏伟侯九霄朱海潮廖金龙海军工程大学振动与噪声研究所船舶振动噪声重点实验室武汉430033 海军潜艇学院作战指挥系山东青岛266199

弹性背腔膜式消声器由弹性背腔以及弹性内膜组成,通过声场与弹性内膜及弹性外膜的耦合作用,降低消声器下游的透射声能,在低频具有较好的宽带消声效果。为求解任意边界条件下的弹性背腔膜式消声器的传递损失,基于能量原理,建立了弹性背... 详细信息

弹性背腔膜式消声器由弹性背腔以及弹性内膜组成,通过声场与弹性内膜及弹性外膜的耦合作用,降低消声器下游的透射声能,在低频具有较好的宽带消声效果。为求解任意边界条件下的弹性背腔膜式消声器的传递损失,基于能量原理,建立了弹性背腔膜式消声器的声振耦合模型。采用边界弹簧约束来实现弹性膜的任意边界条件,进而分析边界约束对传递损失特性的影响。结果表明,理论计算结果与有限元结果吻合良好;结构边界约束对系统声学特性影响显著,增强外膜边界约束,能获得低频宽带消声效果;减弱内膜边界约束,能使最低消声频率向低频移动。

关键词：弹性背腔膜式消声传递损失能量原理边界条件

Aerodynamic Characteristics of Isol.ted l.aded Tires with Different Tread Patterns: Experiment and Simul.tion

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Chinese Journal.of Mechanical.Engineering 2021年第2期34卷 107-122页

作者： haichao Zhou Zhen Jiang Guol.n Wang Shupei Zhang School.of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang 212013China

The current research of tire aerodynamics mainl. focus on the isol.ted and simpl.fied tread *** with the real.compl.x pattern tire,the tread pattern structure and deformed profil. of a l.aded tire has a greatl. infl.ence on tire aerodynamic ***,the mechanisms of the isol.ted l.aded tires with different tread patterns effects on the aerodynamic drag are subjects worthy of *** purpose of this study is to experimental.y and compu-tational.y investigate the aerodynamic characteristics of three tires 185/65 R14 with different patterns under l.aded.A wind tunnel.test model.was first establ.shed using three-dimensional.3D)printing with a ratio of 1:1,and the pres-sure coefficients C_(p) of the three tires with different patterns are *** paper then conducted computational.fl.id dynamics(CFD)simul.tions for anal.zing the pressure and fl.w *** accuracy of CFD simul.tion is verified by comparing the simul.tion resul.s with the test resul.s of pressure coefficients C_(p),and they are of good ***,the general.anal.sis of pressure coefficients C_(p) resul.s of the three tires indicates high-pressure area on the windward surface,and occurrence of l.w-pressure area on the l.eward surface,the pressure coefficients C_(p) of al. three tires decreased firstl. and then increased al.ng in the air fl.w *** authors final.y anal.zed the effect of tread patterns on the fl.w fiel. around the tire and reveal.d the differences between fl.w characteristics and aerodynamic *** resul.s show that,angl. of tire l.teral.groove has great effect on the fl.w fiel. characteristics such that;the more the angl. of l.teral.groove agrees with the air fl.w direction,the l.ss the fl.w separation and fl.w vortices,and a minimum observabl. aerodynamic *** research provides a guidance for the design of l.w aerodynamic drag tires,and hel.s to il.ustrate the impact of tire aerodynamics on the car body in the future.

关键词： Tire aerodynamic Wind tunnel.test Numerical.simul.tion Fl.w anal.sis

基于双目视觉的目标空间定位系统的设计与实现

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计算机应用文摘 2024年第13期40卷 62-65,69页

作者：鲍海潮张捷吕明南京理工大学自动化学院南京210094

近年来,随着工业领域计算机视觉技术的不断发展,基于双目视觉的空间重建技术成为研究和应用的重点之一。针对实体无人档案库房的建设需求,文章设计了一套适用于小区域三维空间重建的系统。该系统采用双目相机搭配六自由度机械臂,并通过... 详细信息

近年来,随着工业领域计算机视觉技术的不断发展,基于双目视觉的空间重建技术成为研究和应用的重点之一。针对实体无人档案库房的建设需求,文章设计了一套适用于小区域三维空间重建的系统。该系统采用双目相机搭配六自由度机械臂,并通过改进Census变换和自适应窗口立体匹配算法实现了档案库房的三维空间重建。经实验验证,该系统能够成功完成实际库房小区域的空间重建任务,为后续的存取任务奠定了基础。

关键词：双目视觉无人库房三维重建系统立体匹配算法目标空间定位

新形势下我国江河入海水通量监测实践与对策建议

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中国环境监测 2024年第1期40卷 21-29页

作者：胡展铭方海超杨永俊林忠胜孙家文国家海洋环境监测中心辽宁大连116023

针对我国入海河口生态环境问题突出、江河入海污染物总量不明的问题,梳理了我国江河入海水通量监测的历史,分析了我国江河入海水通量评估工作的现状以及“十四五”生态环境监测和海洋环境保护等规划的要求,提出污染物排海总量不明的主... 详细信息

针对我国入海河口生态环境问题突出、江河入海污染物总量不明的问题,梳理了我国江河入海水通量监测的历史,分析了我国江河入海水通量评估工作的现状以及“十四五”生态环境监测和海洋环境保护等规划的要求,提出污染物排海总量不明的主要原因是江河入海水通量监测未取得突破,具体表现在江河污染物入海通量未得到有效掌握、江河入海水通量监管体系未得以构建运行、江河入海水通量监测技术未得到建立和规范。结合在辽河口海洋环境在线监测试验基地开展的江河入海流量在线监测系统设计研究、江河入海水通量监测技术研发、江河入海水通量监测技术标准化研究、辽河入海水通量监测试验等工作,建议总结分析我国已开展的江河入海水通量监测试验工作,深入开展江河入海水通量监测顶层设计,加强江河入海水通量监测关键技术方法研究。

关键词：江河入海水通量感潮河段江河入海污染物质通量

HF Communications: Past, Present, and Future

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China Communications 2018年第9期15卷 1-9页

作者： Jinl.ng Wang Guoru Ding haichao Wang Col.ege of Communications Engineering Army Engineering University of PLA National.Mobil. Communications Research l.boratory Southeast University

High frequency(HF) communication, commonl. covering frequency range between 3 and 30 MHz, is an important wirel.ss communication paradigm to offer over-thehorizon or even gl.bal.communications with ranges up to thousands of kil.meters via skywave propagation with ionospheric refraction. It has widespread appl.cations in fiel.s such as emergency communications in disaster areas, remote communications with aircrafts or ships and non-l.ght-of-the-sight mil.tary operations. This tutorial.articl. overviews the history of HF communication, demystifies the recent advances, and provides a preview of the next few years, which the authors bel.eve wil. see fruitful.outputs towards wideband, intel.igent and integrated HF communications. Specifical.y, we first present brief prel.minaries on the unique features of HF communications to facil.tate general.readers in the communication community. Then, we provide a historical.review to show the technical.evol.tion on the three generations of HF communication systems. Further, we highl.ght the key chal.enges and research directions. We hope that this articl. wil. stimul.te more interests in addressing the technical.chal.enges on the research and devel.pment of future HF radio communication systems.

关键词： HF communications skywave propagation ionospheric refraction cognitive radio artificial.intel.igence

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MVR蒸发器及蒸汽压缩机应用比较

化工设计 2024年第2期34卷 35-36,2页

作者：刘殿宇刘海超华禹乳品机械制造有限公司黑龙江安达151400 上海汽车电驱动有限公司上海201801

MVR蒸发器所选用的蒸汽压缩机有离心蒸汽压缩机、罗茨蒸汽压缩机及单级螺杆蒸汽压缩机,前两种是近十几年来普遍采用的压缩机,最后一种是近几年才开始在MVR蒸发器中应用,其最大的特点是在蒸发器工作过程中温升较高,MVR蒸发器是将二次蒸... 详细信息

MVR蒸发器所选用的蒸汽压缩机有离心蒸汽压缩机、罗茨蒸汽压缩机及单级螺杆蒸汽压缩机,前两种是近十几年来普遍采用的压缩机,最后一种是近几年才开始在MVR蒸发器中应用,其最大的特点是在蒸发器工作过程中温升较高,MVR蒸发器是将二次蒸汽通过蒸汽压缩机全部压缩作为加热热源,去蒸发器壳程加热蒸发料液,MVR蒸发器要连续进料连续出料,必须将物料加热至沸点或沸点以上的温度。实际应用中,由于物料进入蒸发器前预热温度较低,有的没有达到沸点或沸点以上的温度,导致不能及时启动压缩机,甚至由于二次蒸汽量不足,压缩机工作过程中出现喘振的事例比较多见;有些蒸发器比较小,使用单位又没有蒸汽热源,大多都是制造厂家提供蒸汽发生器,有的蒸汽发生器产气量过小,致使预热温度迟迟达不到要求温度,也就不能按时启动蒸汽压缩机,这样的事例也比较多见。料液进入蒸发器前的预热效果直接关系到MVR蒸发器能否正常工作,即便预热效果良好,在生产过程中由于沸点升高、热损耗及压缩机本身的需要,也必须补充一定量的额外蒸汽,否则蒸发很难正常进行。要达到理想的蒸发状态,在诸多影响因素中,蒸汽压缩机喷淋水有多少气化参与了加热,也很重要。本文就MVR蒸发器及三种压缩的应用进行阐述,为同类应用提供参考。

关键词： MVR蒸发器蒸汽压缩机应用

分类培育:“一老一小”型社区社会企业发展策略分析

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湖北工程学院学报 2024年第2期44卷 101-105页

作者：谢正富施海潮岭南师范学院社会与公共管理学院广东湛江524000 襄阳市民政局湖北襄阳441000

本文依据“三部门”理论将社区社会企业分为公共性、营利性、公益性三类,并提出分类培育“一老一小”型社区社会企业的发展策略,从组织身份分类认定、金融财税分类支持、从业人员分类培训、创业投资分类资助四个方面对“一老一小”型社... 详细信息

本文依据“三部门”理论将社区社会企业分为公共性、营利性、公益性三类,并提出分类培育“一老一小”型社区社会企业的发展策略,从组织身份分类认定、金融财税分类支持、从业人员分类培训、创业投资分类资助四个方面对“一老一小”型社区社会企业进行分类培育。

关键词：一老一小社区社会企业分类培育