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Mixing Characteristics of Pulsed Air-assist Liquid Jet into an Internal Subsonic Cross-flow

Journal of Thermal Science 2010年第2期19卷 136-140页

作者： Inchul Lee youngsu kang Jaye Koo Graduate Student Korea Aerospace University School of Aerospace and Mechanical Engineering Korea Aerospace University

Penetration depth,spray dispersion angle,droplet sizes in breakup processes and atomization processes are very important parameters in combustor of air-breathing *** processes will enhance air/fuel mixing inside the *** results from the pulsed air-assist liquid jet injected into a cross-flow are *** experiments were conducted to a range of cross-flow velocities from 42～136 m/*** is injected with 0～300kPa,with air-assist pulsation frequency of 0～*** frequency was modulated by solenoid *** Doppler Particle Analyzer(PDPA) was utilized to quantitatively measuring droplet ***-speed CCD camera was used to obtain injected spray *** air-assist liquid jet will offer rapid mixing and good liquid jet ***-assist makes a very fine droplet which generated mist-like *** air-assist liquid jet will introduce additional supplementary turbulent mixing and control of penetration depth into a cross-flow *** results show that pulsation frequency has an effect on penetration,transverse velocities and droplet *** experimental data generated in these studies are used for a development of active control strategies to optimize the liquid jet penetration in subsonic cross-flow conditions and predict combustion low frequency instability.

关键词： cross-flow penetration pulsed air-assist liquid jet pulsation frequency

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Broadband omnidirectional light detection in flexible and hierarchical ZnO/Si heterojunction photodiodes

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Nano Research 2017年第1期10卷 22-36页

作者： Seongdong Lim Doo-Seung Um Minjeong Ha Qianpeng Zhang youngsu Lee Yuanjing Lin Zhiyong Fan Hyunhyub Ko School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan Metropolitan City 44919 Republic of Korea Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China

The development of flexible photodetectors has received great attention for future optoelectronic applications including flexible image sensors, biomedical imaging, and smart, wearable systems. Previously omnidirectional photodetectors were only achievable by integration of a hemispherical microlens assembly on multiple photodetectors. Herein, a hierarchical photodiode design of ZnO nanowires （NWs） on honeycomb-structured Si （H-Si） membranes is demonstrated to exhibit excellent omnidirectional light-absorption ability and thus maintain high photocurrents over broad spectral ranges （365 to 1,100 nm） for wide incident angles （0° to 70°）, which enabled broadband omnidirectional light detection in flexible photodetectors. Furthermore, the stress-relieving honeycomb pattern within the photodiode micromembranes provided photodetectors with excellent mechanical flexibility （10% decrease in photocurrent at a bending radius of 3 mm） and durability （minimal change in photocurrent over 10,000 bending cycles）. When employed in semiconductor thin films, the hierarchical NW/honeycomb heterostructure design acts as an efficient platform for various optoelectronic devices requiring mechanical flexibility and broadband omnidirectional light detection.

关键词： flexible photodetector photodiode omnidirectional hierarchicalzinc oxide nanowire

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Platinum quantum dots-decorated MXene-derived titanium dioxide nanowire/Ti_(3)C_(2) heterostructure for use in solar-driven gas-phase carbon dioxide reduction to yield value-added fuels

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Journal of Energy Chemistry 2023年第7期82卷 627-637,I0013页

作者： Kamakshaiah Charyulu Devarayapalli S.V.Prabhakar Vattikuti Dong Jin Kim youngsu Lim Bolam Kim Gyuhyeon Kim Dae Sung Lee Department of Environmental Engineering Kyungpook National UniversityBuk-guDaegu 41566Republic of Korea Research Institute of Environmental Science&Technology Core Research InstituteKyungpook National UniversityBuk-guDaegu 41566Republic of Korea School of Mechanical Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea School of Architecture CivilEnvironmental and Energy EngineeringKyungpook National UniversityBuk-guDaegu 41566Republic of Korea

Solar-driven photocatalytic CO_(2) reduction to produce valuable chemicals and fuels offers an attractive strategy in alleviating the energy *** quantum dots(PtQDs)with TiO_(2) nanowire(TiO_(2)NW)/Ti_(3)C_(2) MXene heterostructures(Pt-TiO_(2)NW/Ti_(3)C_(2)) with tight interfacial contacts between the various components were prepared at room temperature via oxidation *** incorporated PtQDs played crucial roles as electron conduction bridges supported by the cocatalyst effect,effectively enhancing the separation efficiencies of photoinduced electron/hole pairs and improving CO_(2) reduction under simulated solar light *** Pt-TiO_(2)NW/Ti_(3)C_(2) heterostructures exhibited remarkable carbon monoxide(CO)and methane(CH_(4)) production at respective rates of 38.14 and 36.15μmol g^(-1)after 10 h of simulated solar light irradiation,an apparent quantum yield of 1.68%,and 79.2%selectivity for *** photocatalytic activities of the Pt-TiO_(2) NW/Ti_(3)C_(2) heterostructures for CO_(2) reduction were significantly enhanced compared to those of TiO_(2)NW/Ti_(3)C_(2) and the single-component photocatalysts,and they exhibited remarkable stabilities even after five *** addition,the densities of states and electronic characteristics of Ti_(3)C_(2) MXene and Pt-TiO_(2)NW/Ti_(3)C_(2) were studied using density functional theory,and a synergistic mechanism of the improvement in CO_(2) photoreduction is proposed.

关键词： MXene CO_(2)reduction Density functional theory Quantum dot Photocatalyst

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中韩不同林业政策下森林可持续经营对比研究

中韩不同林业政策下森林可持续经营对比研究

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作者：朴莹洙（Park youngsu）北京林业大学

学位级别：硕士

自十九世纪90年代初以来,全球社会已将可持续发展视为全球、区域、国家和地方范围的愿景。在林业领域,森林可持续发展原则是许多国家在1992联合国环境与发展会议上签署的一项无法律约束力的林业协定。中国和韩国两国在地理位置、气候条... 详细信息

自十九世纪90年代初以来,全球社会已将可持续发展视为全球、区域、国家和地方范围的愿景。在林业领域,森林可持续发展原则是许多国家在1992联合国环境与发展会议上签署的一项无法律约束力的林业协定。中国和韩国两国在地理位置、气候条件等方面存在着许多相似之处,但是两国国内的地形、自然条件和森林覆盖面积上存在着明显的不同。与中国相比,韩国的林业发展速度比较快,国内的森林覆盖面积明显要比中国高很多。韩国的林业在经历了几十年的发展过程以后,国内的森林已经基本形成了以国有制森林、公有制森林以及私有制森林三种所有制共存的发展模式,这其中私有制森林的面积最大,其次是国有制森林,面积最小的是公有制森林。随着韩国森林面积的不断提升,在韩国政府的引导下,韩国的林业部门还在发展森林经济、建立可持续发展林业生态方面制定了许多行之有效的政策与制度,为韩国林业的可持续发展提供了可靠的政策支持。本论文采用定性文献分析法、比较分析法、实证分析法,以不同林业政策下的中韩两国林业政策进行研究。本文主要包括五个部分:第一部分是中韩林业资源概况;第二部分是对中韩林业政策对比研究。第三部分是中韩进行中的森林政策对比;第四部分是是关于韩国林业政策与森林资源影响因素的实证分析;第五部分是中韩森林政策下森林可持续经营展望。最后,本文得出结论,韩国森林可持续发展要进一步完善森林服务的内容和产业链;中国森林可持续发展要针对天然形成的森林制定相应的保护措施,其次要实行退耕还林计划,针对风沙源头制定的风沙治理工程;针对东北、华北、西北以及长江流域实施的防护林工程;根据各地区的实际情况与生态环境建立野生动物保护区以及各级别的自然保护区。最后,为了解决社会发展对木材的需求问题,建立快速生长的用材林基地。

关键词：中韩林业可持续经营林业政策

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