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Asymmetric synthesis of tricyclic 6,5,5-fusedpolycycles by the desymmetric Pauson–Khandreaction

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Organic Chemistry Frontiers 2022年第6期9卷 1680-1685页

作者： Qi teng Dong Chen Chen-ho Tung Zhenghu Xu Key Lab of Colloid and Interface Chemistry of Ministry of Education School of Chemistry and Chemical EngineeringShandong UniversityNo.27 South Shanda RoadJinanShandong 250100China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of SciencesShanghai 200032PR China Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province School of ScienceWestlake University18 Shilongshan RoadHangzhou 310024Zhejiang ProvinceChina

A new rhodium(I)–BINAP-catalyzed enantioselective desymmetric Pauson–Khand (PK) reaction of prochiral 1,6-enynes with CO has been developed. Diverse tricyclic 6,5,5-fused bowl type polycycles withthree continuous ch... 详细信息

关键词： fused symmetric chiral

Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing

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Light(Science & Applications) 2014年第1期3卷 147-154页

作者： Jing Yang Fangfang Luo Tsung Sheng Kao Xiong Li Ghim Wei ho Jinghua teng Xiangang Luo Minghui hong Department of Electrical and Computer Engineering National University of SingaporeSingapore 117576Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and ResearchSingapore 117602Singapore NUS Environmental Research Institute National University of SingaporeSingapore 117411Singapore State Key Laboratory of Optical Technologies for Microfabrication Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China

Light collection efficiency is an important factor that affects the performance of many optical and optoelectronic *** these devices,the high reflectivity of interfaces can hinder efficient light *** minimize unwanted reflection,anti-reflection surfaces can be fabricated by micro/*** this paper,we investigate the fabrication of broadband anti-reflection Si surfaces by laser micro/*** direct writing is applied to create microstructures on Si surfaces that reduce light reflection by light *** addition,laser interference lithography and metal assisted chemical etching are adopted to fabricate the Si nanowire *** anti-reflection performance is greatly improved by the high aspect ratio subwavelength structures,which create gradients of refractive index from the ambient air to the ***,by decoration of the Si nanowires with metallic nanoparticles,surface plasmon resonance can be used to further control the broadband reflections,reducing the reflection to below 1.0%across from 300 to 1200 *** average reflection of 0.8%is achieved.

关键词： anti-reflection broadband laser micro/nanoprocessing surface plasmons

Differences in respiration components and their dominant regulating factors across three alpine grasslands on the Qinghai−Tibet Plateau

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Advances in Climate Change Research 2023年第3期14卷 437-448页

作者： Ya-Li LIU Jun-Feng WANG Guan-Li JIANG Lu-Yang WANG Zi-teng FU ho-Jeong KANG Qing-Bai WU State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment State Key Laboratory of Frozen Soil EngineeringNorthwest Institute of Eco-Environmental and ResourcesChinese Academy of SciencesLanzhou 730000China School of Civil and Environmental Engineering Yonsei UniversitySeoul 03722South Korea

Greenhouse gases(GHGs)emissions from high-cold terrestrial ecosystems underlain by permafrost on the Qinghai–Tibet Plateau(QTP)have received widespread ***,the dominant factors regulating ecosystem respiration(Re)and its components(soil respiration Rs and heterotrophic respiration Rh)and how the differences in carbon emissions from different ecotypes and seasons remain are still *** conducted a 2-year field investigation(August 2018 to October 2020)and applied the structural equation model(SEM)to clarify the changes in the factors controlling the respiration components during different *** results indicate that the R_(e)and its controlling factors in three alpine grassland ecosystems(alpine steppe,alpine meadow,and swamp meadow)vary with ***,autotrophic respiration(Ra)contributes the most to the seasonal changes in R_(e).The R_(e)gradually increases in the early growing season and rapidly decreases in the late growing *** remains relatively stable during the *** these seasonal variations in the respiration components,the dominant factors controlling R_(e)in the nongrowing season are the temperature of the atmosphere–soil interface(heat flux,atmospheric temperature,and soil temperature at 5 cm depth)and microbial activity(microbial carbon and pH)with the variable importance projections>*** the growing season,the dominant factors regulating R_(e),Rs,and Rh are the soil temperature with a standardized direct effect(SDE)of 0.424,soil nutrient conditions(total nitrogen and pH)with SDEs of 0.570–0.614,and microbial activity(microbial carbon)with a SDE of 0.591,*** addition,meteorological conditions have an important impact on the respiration components during the growing ***,the atmospheric vapor pressure is the dominant factor regulating the three respiration components(standardized total effects=0.44−0.53,p<0.001).The optimal soil water contents during the growing season(water c

关键词： Ecosystem respiration Respiration components Atmospheric vapor pressure Alpine grassland Permafrost QinghaieTibet Plateau

3D printing for ultra-precision machining:current status,opportunities,and future perspectives

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Frontiers of Mechanical Engineering 2024年第4期19卷 1-28页

作者： Tao HE Wai Sze YIP Edward Hengzhou YAN Jiuxing TANG Muhammad REHAN Long teng Chi ho WONG Linhe SUN Baolong ZHANG Feng GUO Shaohe ZHANG Suet TO State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina Department of Physics The Hong Kong University of Science and TechnologyHong KongChina School of Geosciences and Info-Physics Central South UniversityChangsha 410083China

Additive manufacturing,particularly 3D printing,has revolutionized the manufacturing industry by allowing the production of complex and intricate parts at a lower cost and with greater ***,3D-printed parts frequently require post-processing or integration with other machining technologies to achieve the desired surface finish,accuracy,and mechanical ***-precision machining(UPM)is a potential machining technology that addresses these challenges by enabling high surface quality,accuracy,and repeatability in 3D-printed *** study provides an overview of the current state of UPM for 3D printing,including the current UPM and 3D printing stages,and the application of UPM to 3D *** the presentation of current stage perspectives,this study presents a detailed discussion of the benefits of combining UPM with 3D printing and the opportunities for leveraging UPM on 3D printing or supporting each *** particular,future opportunities focus on cutting tools manufactured via 3D printing for UPM,UPM of 3D-printed components for real-world applications,and post-machining of 3D-printed ***,future prospects for integrating the two advanced manufacturing technologies into potential industries are *** study concludes that UPM is a promising technology for 3D-printed components,exhibiting the potential to improve the functionality and performance of 3D-printed products in various *** also discusses how UPM and 3D printing can complement each other.

关键词： ultra-precision machining 3D printing additive manufacturing future perspectives start-of-the-art-review

Texture evolution prediction of 2219 aluminum alloy sheet under hydro-bulging using cross-scale numerical modeling

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Journal of Materials Science & Technology 2023年第18期149卷 190-204页

作者： Yanbo Pei Yonggang Hao Jie Zhao Jiantong Yang Bugang teng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China National Key Laboratory for Precision hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Department of Materials Science and Engineering China University of Mining&Technology(Beijing)Beijing 100083China

A simultaneous prediction of macroscopic deformation and microstructure evolution is critical for un-derstanding the deformation mechanism of *** this work,the hydro-bulging process of 2219 aluminum alloy sheet was investigated using cross-scale numerical modeling,in which the macroscopic finite element method(FEM)and crystal plasticity finite element method(CPFEM)were *** calculated texture evolution exhibits good agreement with the experimental results,and the stress er-ror between the two scales is generally *** effects of different strain states on texture evolution and slip mode are further *** the strain ratioηincreases,the volume fractions of the initial Rotated Copper texture component andγ-Fiber texture component decrease significantly,which tend to be stabilized at P texture *** initial Rotated Cube texture component is inclined to rotate towards the Cube texture component,while the volume fraction of this orientation is relatively *** lower strain ratio can considerably enhance the activity of more equivalent slip systems,promoting a more uniform strain distribution over *** difficulty of grain deformation changes as the lat-tice *** grain with easy-to-deform orientation can gradually rotate to a stable orientation during plastic deformation,which has a lower Schmid factor.

关键词： Cross-scale modeling Crystal plasticity Texture evolution Aluminum alloy Hydro-bulging forming

The genetic diversity, individual relatedness and possible mating system of an isolated population of the Cyprinid species Megalobrama pellgrini in upper reaches of the Changjiang (Yangtze) River, China

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Journal of Oceanology and Limnology 2019年第3期37卷 1042-1050页

作者： WANG Huanshan WANG teng LI Wenjing LIU Huanzhang The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences Institute of HydrobiologyChinese Academy of SciencesWuhan 430072China University of Chinese Academy of Sciences Beijing 100049China

Megalobrama pellegrini is a cyprinid fish endemic to upper reaches of the Changjiang(Yangtze)River,China,which is also an important economic species in the local *** recent years,resources of this species have decreased sharply and its conservation has drawn great *** the present study,we collected 120 individuals from the Longxi River,a tributary isolated from the main channel of the Changjiang River,where *** is still relatively *** two different molecular markers,mitochondrial cytochrome b(cyt b)gene,and nuclear microsatellite(simple sequence repeat,SSR),we analyzed the genetic diversity of this isolated *** results show that sequence genetic diversity was low(Hd:0.290 and P i:0.000 77 for cyt b gene),while the SSR genetic diversity was high(ho:0.824 4±0.147 2,He:0.823 5±0.145 1).Analysis indicated that this population had experienced a bottleneck,with inbreeding and small effective population size(around 50).Based on SSR data,relatedness analyzing revealed that the 120 samples were grouped into 10 completely independent *** was inferred that the mating system of *** was *** suggested that the low genetic diversity could be induced by the overfishing and inbreeding ***,we suggested that the urgent conservation measures should be taken to control the overfi shing and give better conditions for the fish to grow and spawn,then to restore population size.

关键词： isolated population genetic diversity individual relatedness mating system conservation

late-stage rapid accumulation of the PL19-3 giant oilfield in an active fault zone during Neotectonism in the Bozhong depression,Bohai Bay

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Science China Earth Sciences 2011年第3期54卷 388-398页

作者： ZOU HuaYao GONG ZaiSheng teng ChangYu ZHUANG XinBin State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China China National Offshore Oil Corporation Beijing 100027 China

late-stage is defined here as the period when Neotectonism occurred since 5.1 Ma. Most petroliferous basins in China lie in the areas where Neotectonism occurred intensively. In recent years, Chinese petroleum geologists have paid much attention to late-stage petroleum accumulation. The PL19-3 giant oilfield is situated where faulting activities occurred violently during Neotectonism. To understand the mechanism of lat-stage rapid accumulation, we discussed the most important aspects responsible for the formation of the giant oilfield, including oil generation, active oil-source rock occurrence, fault activity and fault conduits, late-stage rapid oil injection as well as the distinguishing indicators. This study shows that: (1) sufficient oil was supplied to the PL19-3 field since 5.1 Ma because the PL19-3 structure was surrounded by four sags in which three intervals of high-quality source rocks remained active during Neotectonism; (2) densely distributed faults and high porosity/permeability sandstone carrier beds comprised the effective conduit system for oil migration and injection; (3) oil migrated along the faults and charged the PL19-3 structure rapidly by means of seismic pumping which was triggered by frequent earthquakes during Neotetonism. It is documented that elevated reservoir temperature, abnormal geothermal gradients and abnormally high homogenization temperatures of the fluid inclusions are the indicators for late-stage rapid oil accumulation.

关键词： Neotectonism active oil-source rock (AOSR) migration conduit late-stage rapid accumulation PL19-3 oilfield Bozhong depression

Elemental mercury (Hg^(0)) removal from coal syngas using magnetic tea-biochar: Experimental and theoretical insights

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Journal of Environmental Sciences 2022年第12期34卷 150-161页

作者： Adnan Raza Altaf Yusuf GAdewuyi Haipeng teng Gang Liu Fazeel Abid School of Chemical Engineering Northwest University Xi’an 710069China Chemical Biological and Bio Engineering DepartmentNorth Carolina Agricultural and Technical State UniversityGreensboroNC 27411USA State Key Laboratory of Clean Coal-based Energy China Huaneng Group Clean Energy Research Institute Co.Ltd.Changping DistrictBeijing 102209China Department of Information System Dr Hassan Murad School of ManagementUniversity of Management and TechnologyLahore 54770Pakistan

Mercury is ranked 3^(rd)as a global pollutant because of its long persistence in the environment. Approximately 65% of its anthropogenic emission (Hg^(0)) to the atmosphere is from coal-thermal power plants. Thus, the Hg^(0)emission control from coal-thermal power plants is inevitable. Therefore, multiple sorbent materials were synthesized using a one-step pyrolysis method to capture the Hg^(0)from simulated coal syngas. Results showed, the Hg^(0)removal performance of the sorbents increased by the citric acid/ultrasonic application.T5CUF_(0.3)demonstrated the highest Hg^(0)capturing performance with an adsorption capacity of 106.81 μg/g within 60 min at 200 °C under complex simulated syngas mixture (20% CO,20% H_(2), 10 ppm V HCl, 6% H_(2)O, and 400 ppm V H_(2)S). The Hg^(0)removal mechanism was proposed, revealing that the chemisorption governs the Hg^(0)removal process. Besides, the active Hg^(0)removal performance is attributed to the high dispersion of valence Fe_(3)O_(4)and lattice oxygen (α) contents over the T5CUF_(0.3)surface. In addition, the temperature programmed desorption (TPD) and XPS analysis confirmed that H_(2)S/HCl gases generate active sites over the sorbent surface, facilitating high Hg^(0)adsorption from syngas. This work represented a facile and practical pathway for utilizing cheap and eco-friendly tea waste to control the Hg^(0)emission.

关键词： Mercury removal Waste management Citric acid Ultrasound Coal gasification TPD analysis

Origin of the Neoproterozoic Baijianshan Banded Iron Formation at the Southeastern Margin of the Tarim Block in NW China:Implication for an Extremely Reducing Ocean

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Acta Geologica Sinica(English Edition) 2022年第1期96卷 208-220页

作者： HAO Xiaoshu ZHANG Chuanlin ZHANG Huichao DING teng YE Xiantao College of Oceanography Hohai UniversityNanjing 210024China

The Neoproterozoic banded iron formations(BIFs)were closely associated with the“Snowball Earth”during the breakup of the Rodinia,thus they played an important role in our understanding of the atmospheric and oceanic oxygen levels during this *** this contribution,the Neoproterozoic(ca.737 Ma)Baijianshan BIF at Southeast Tarim,northwestern China was *** is the dominated iron-species,which occurs as the lamina interbedded with *** BIF contains low concentrations of trace elements,and is depleted in light rare earth elements(LREEs)based on comparison with the Post-Archean Australian Shale(PAAS).In addition,the BIF exhibits slightly positive La-Eu anomalies,negligible Ce anomalies,insignificant Y anomalies,chondritic Y/ho ratios(23-32),and slightly chondritic initial ε_(Nd)(t=737 Ma)values(−0.45 to 1.46,averaging 0.37).All these features indicate that the precipitation of Baijianshan BIF was closely related to the submarine low-T hydrothermal fluids with little detrital ***,the Baijianshan BIF is characterized by the significant enrichment of heavy Fe isotopes,with δ^(57)Fe_(IRMM-014) values ranging from 1.78‰ to 3.05‰,revealing the partial oxidation of Fe^(2+) into Fe^(3+) during the precipitation of this *** data suggest that the formation of Baijianshan BIF was closely associated with a significantly reducing ocean,which most likely was isolated from the oxidized atmosphere by a local ice *** Neoproterozoic Baijianshan ocean has the initial oxygen levels as low as,or even lower than that of Archean and Paleoproterozoic oceans.

关键词： Neoproterozoic banded iron formations(BIFs) Sr-Nd isotope Fe isotope Tarim Block