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natural regeneration responses to thinning and burning treatments in ponderosa pine forests and implications for restoration

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Journal of Forestry Research 2022年第3期33卷 741-753页

作者： Tzeidle n.wasserman Amy E.m.waltz john Paul Roccaforte Judith D.Springer Joseph E.Crouse Ecological Restoration Institute Northern Arizona UniversityP.O.Box 15017FlagstaffAZ86011-5017USA

Understanding naturally occurring pine regeneration dynamics in response to thinning and burning treatments is necessary not only to measure the longevity of the restoration or fuels treatment,but also to assess how well regeneration meets forest sustainability guidelines and whether natural regeneration is sufficient for maintaining a sustainable forest structure and composition.A synthesis review was carried out on the effects of mechanical thinning and prescribed burn treatments on natural pine regeneration response in frequent-fire ponderosa pine forests across the western United *** focus was on site-specific variability in pine regeneration dynamics,temporal trends in regeneration presence and abundance,and response to treatment as described in the current literature using 29 studies that met our evidence-based review *** showed that the effects of thinning and burning treatments on regeneration depended on time since *** thinning,prescribed burning,and thinning plus burn treatments all increased seedling density,but there was high variability among sites and *** were mixed results in the short-term(with both increasing and decreasing regeneration,and a general increase in regeneration 11−20 years *** long-term studies(>20 years)concluded that stands can return to pre-treatment densities in terms of total trees per hectare and forest floor duff levels when there are no maintenance treatments *** studies showed the average ponderosa pine seedling presence,survival and growth found in today’s forests to be at a high density;this combined with missed fire cycles could contribute to future fire risk and reduce the efficacy of maintaining fuel reduction goals.

关键词： Regeneration Ponderosa pine Frequent-fire Treatments Thinning Burning

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Zinc Oxide-Based Q-Switched Erbium-Doped Fiber Laser

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Chinese Physics Letters 2017年第4期34卷 43-45页

作者： n.A.Aziz A.A.Latiff m.Q.Lokman E.Hanafi S.w.Harun Department of Electrical Engineering Faculty of Engineering University of Malaya Kuala Lumpur 50603 Malaysia Photonics Research Centre University of Malaya Kuala Lumpur 50603 Malaysia

we demonstrate a Q-switched erbium-doped fiber laser （EDFL） using a newly developed zinc oxide- （ZnO） based saturable absorber （SA）. The SA is fabricated by embedding a prepared ZnO powder into a poly（vinyl alcohol） film. A small piece of the film is then sandwiched between two fiber ferrules and is incorporated in an EDFL cavity for generating a stable Q-switching pulse train. The EDFL operates at 1560.4nm with a pump power threshold of 11.8mw, a pulse repetition rate tunable from 22.79 to 61.43kHz, and the smallest pulse width of 7.00 μs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 62 dB indicating the high stability of the laser. These results show that the ZnO powder has a great potential to be used for pulsed laser applications.

关键词： Zinc Oxide-Based Q-Switched Erbium-Doped Fiber Laser SA ZnO

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High strength Al-Cu-mg based alloy with synchronous improved tensile properties and hot-cracking resistance suitable for laser powder b e d fusion

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Journal of materials Science & Technology 2023年第10期141卷 155-170页

作者： Q.Z.wang n.Kang X.Lin m.EL mansori w.D.Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Arts et metiers Institute of Technology MSMPHESAM UniversitéChâlons-en-Champagne F-51006France Key Laboratory of metal High Performance Additive manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China Texas A&m Engineering Experiment Station Institute for Manufacturing SystemsCollege StationTX 77843USA

In present work,a novel crack-free Al-Cu-mg-Si-Ti alloy with synchronous improved tensile properties and hot-cracking resistance was proposed and successfully manufactured by laser powder bed fusion(LPBF).The microstructure evolution behaviors and the corresponding strengthening mechanisms were investigated in *** LPBF-processed Al-Cu-mg-Si-Ti alloy presents a heterogeneous microstructure consisting of ultrafine equiaxed grains(UFGs)at the boundary and coarse columnar grains(CGs)at the center of the single molten ***-precipitated D022-Al 3 Ti particles were found to act as the nuclei to refine the grains at the boundary of the molten pool during solidification process,which is attributed to the low cooling rate providing the sufficient incubation time for the precipitation of D022-Al 3 *** are two orientation relationships(ORs)betweenα-Al and D022-Al 3 Ti,i.e.[001]α-Al//[001]D022-Al3Ti,(200)α-Al//(200)D022-Al3Ti and[1¯1¯2]α-Al//[¯111]D022-Al3Ti,(1¯11)α-Al//(¯11¯2)D022-Al3Ti,which are two of the eight ORs predicted with the E2Em *** grains in present alloy,no matter for UFGs or CG,exhibited high critical hot-cracking stress,which means a strong hot-cracking ***-nanoprecipitation of Cu-,mg-,and Si-rich Q’and S’phases was introduced to enhance the mechanical performance ofα-Al *** as-built sample exhibits superior tensile properties,with the yield strength(YS)of 473±8 mPa,ultimate tensile strength(UTS)of 541±2 mPa and elongation(EI)of 10.9%±1.2%.

关键词： Laser powder bed fusion High strength Al-Cu-mg alloys Duplex microstructure Precipitation Tensile properties

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Delineation of groundwater potential zones in Theni district,Tamil nadu,using remote sensing,GIS and mIF techniques

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Geoscience Frontiers 2012年第2期3卷 189-196页

作者： n.S.magesh n.Chandrasekar john Prince Soundranayagam Centre for Geotechnology manonmaniam Sundaranar University

Integration of remote sensing data and the geographical information system （GIS） for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessing, monitoring, and conserving groundwater resources. In the present paper, various groundwater potential zones for the assessment of groundwater availability in Theni district have been delineated using remote sensing and GIS techniques. Survey of India toposheets and IRS-IC satel- lite imageries are used to prepare various thematic layers viz. lithology, slope, land-use, lineament, drainage, soil, and rainfall were transformed to raster data using feature to raster converter tool in ArcGIS. The raster maps of these factors are allocated a fixed score and weight computed from multi influencing factor （mIF） technique. moreover, each weighted thematic layer is statistically computed to get the groundwater potential zones. The groundwater potential zones thus obtained were divided into four categories, viz., very poor, poor, good, and very good zones. The result depicts the groundwater potential zones in the study area and found to be helpful in better planning and management of ground- water resonrces.

关键词： Groundwater potential zones India Remote sensing Geographic information system mIF technique

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nanosecond Pulses Generation with Samarium Oxide Film Saturable Absorber

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Chinese Physics Letters 2019年第7期36卷 48-51页

作者： n.F.Zulkipli m.Batumalay F.S.m.Samsamnun m.B.H.mahyuddin E.Hanafi T.F.T.m.n.Izam m.I.m.A.Khudus S.w.Harun Photonics Engineering Laboratory Department of Electrical Engineering University of Malaya Kuala Lumpur 50603 Malaysia Faculty of Information Technology & Sciences Inti International University Perdana BBN Putra Nilai Nilai 71800 Negeri Sembilan Department of Physics University of Malaya Kuala Lumpur 50603 Malaysia Department of Physics Faculty of Science and Technology Airlangga University Surabaya Indonesia

nanosecond pulse generation is demonstrated in a mode-locked erbium-doped fiber laser(EDFL) utilizing a samarium oxide(Sm2O3) film. The Sm2O3 film exhibits a modulation depth of 33%, which is suitable for modelocking operation. The passively pulsed EDFL operates stably at 1569.8 nm within a pumping power from 109 to 146 m w. The train of generated output pulses has a pulse width of 356 nm repeated at a fundamental frequency of 0.97 mHz. The average output power of 3.91 m w is obtained at a pump power of 146 m w, corresponding to 4.0 nJ pulse energy. The experimental result indicates that the proposed Sm2O3 saturable absorber is viable for the construction of a flexible and reliably stable mode-locked pulsed fiber laser operating in the 1.5 m region.

关键词： nanosecond pulse generation erbium-doped fiber laser in the 1.5 m region

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Competition for shelter between four invasive gobiids and two native benthic fish species

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Current Zoology 2011年第6期57卷 844-851页

作者： n. VAn KESSEL m. DOREnBOSCH m.R.m. DE BOER R.S.E.w. LEUVEn G. VAn DER VELDE Radboud University nijmegen Institute for Water and Wetland Research Department of Animal Ecology and Ecophysiology EO. Box 9010 6500 GL Nijmegen The Netherlands Radboud University nijmegen Institute for Water and Wetland Research Department of Environmental Science P.O. Box 9010 6500 GL Nijmegen The Netherlands natuurbalans - Limes Divergens P.O. Box 31070 6503 CB Nijmegen The Netherlands netherlands Institute of Ecology （nIOO - KnAw） EO. Box 50 6700 AB Wageningen The Netherlands netherlands Centre for Biodiversity naturalis EO. Box 9517 2300 RA Leiden The Netherlands

Recent invasions by non-native gobiid fish species that are ongoing in the western European rivers Rhine and meuse, will lead to interactions with native benthic fish species. Since both non-native gobiids and native benthic species are bottom dwelling species with a preference for shelter during at least part of their life cycle, it is likely that competition for shelter will occur between these non-native and native species when shelter is a limiting factor. To investigate the importance of this mecha- nism for species replacements, various habitat choice experiments were conducted between two common native benthic fish spe- cies （Cottus perifretum and Barbatula barbatula） and four invasive non-native gobiid species （Proterorhinus semilunaris, neogo- bius melanostomus, n. kessleri and n. fluviatilis）. The first series of single specimen experiments determined the habitat choice of each individual fish species. In a second series of competition experiments, shifts in habitat choice in comparison with the previ- ously observed habitat choice, were determined when a native benthic fish species co-occurred with non-native gobiid species. native C. perifretum displayed a significant shift in habitat choice in co-occurrence with the gobiids n. kessleri or P. semilunaris. C. perifretum was outcompeted and moved from the available shelter place to less preferred habitat types. During the competition experiments no change in habitat choice of B. barbatula was shown. Our study therefore suggests that competition for shelter is likely to occur in rivers invaded by n. kessleri and P. semilunaris at sites where shelter is limiting

关键词： Bullhead Exotic species Habitat choice Invasive gobies Rivers Rhine and meuse Stone loach

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Virus entry mediated by hepatitis B virus envelope proteins

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world Journal of Gastroenterology 2013年第40期19卷 6730-6734页

作者： john m Taylor Fox Chase Cancer Center PhiladelphiaPA19111United States

Hepatitis B virus(HBV),a major cause of human liver disease worldwide,encodes three envelope proteins needed for the attachment and entry of the virus into susceptible host cells.A second virus,hepatitis delta virus,which is known to enhance liver disease in HBV infected patients,diverts the same HBV envelope proteins to achieve its own assembly and *** the lab,lentiviral vectors based on human immunodeficiency virus type 1 can be assembled using the HBV envelope proteins,and will similarly infect susceptible *** article provides a partial review and some personal reflections of how these three viruses infect and of how recipient cells become susceptible,along with some consideration of questions that remain to be answered.

关键词： Hepatitis B virus Hepatitis delta virus Receptor Envelope proteins Entry

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OH and O radicals production in atmospheric pressure air/Ar/H_2O gliding arc discharge plasma jet

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Plasma Science and Technology 2017年第12期19卷 71-80页

作者： n C ROY m R TALUKDER A n CHOwDHURY Plasma Science and Technology Laboratory Department of Applied Physics and Electronic EngineeringUniversity of RajshahiRajshahi 6205Bangladesh Bangladesh Council of Scientific and Industrial Research Laboratory Rajshahi Rajshahi 6206Bangladesh

Atmospheric pressure air/Ar/H_2O gliding arc discharge plasma is produced by a pulsed dc power supply. An optical emission spectroscopic（OES） diagnostic technique is used for the characterization of plasmas and for identifications of OH and O radicals along with other species in the plasmas. The OES diagnostic technique reveals the excitation Tx？≈？5550–9000 K, rotational Tr？≈？1350–2700 K and gas Tg？≈？850–1600 K temperatures, and electron density n？（1.1-1.9） ′101 4 cm^（-3） e under different experimental conditions. The production and destruction of OH and O radicals are investigated as functions of applied voltage and air flow rate. Relative intensities of OH and O radicals indicate that their production rates are increased with increasing Ar content in the gas mixture and applied voltage. nereveals that the higher densities of OH and O radicals are produced in the discharge due to more effective electron impact dissociation of H_2O and O_2 molecules caused by higher kinetic energies as gained by electrons from the enhanced electric field as well as by enhanced n *** productions of OH and O are decreasing with increasing air flow rate due to removal of Joule heat from the discharge region but enhanced air flow rate significantly modifies discharge maintenance properties. Besides, Tgsignificantly reduces with the enhanced air flow rate. This investigation reveals that Ar plays a significant role in the production of OH and O radicals.

关键词： reactive oxygen species(ROS) optical emission spectroscopy(OES) gliding arc discharge plasma kinetics broadening mechanism

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Heat Capacity and Thermal Expansion of water and Helium

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Journal of Thermal Science 2017年第2期26卷 125-131页

作者： n.m.Putintsev D.n.Putintsev Department of Chemistry Murmansk State Technical UniversitySt.Sport 13183010MurmanskRussia Institute for Systems Analysis Federal Research Center《Computer Science and Controb》of the Russian Academy of SciencesPr.60-Letiya Oktyabrya9117312MoscowRussia

Original expressions for heat capacity CV and its components, vibrational and configurational components of thermal expansion coefficient were established. The values of CV, Cvib, Cconf, Cvib and Cconf for water and h... 详细信息

关键词： heat capacity thermal expansion coefficient isothermal compressibility vibrational input configurational input water helium 4.

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导航波流体力学

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力学进展 2021年第1期51卷 155-177页

作者： John.w.m.Bush 王展(译) 韦小丁(校) 麻省理工学院数学系马萨诸塞州剑桥02139 中国科学院力学研究所北京大学

Yves Couder,Emmanuel Fort和同事们最近发现能够维持在振荡液体表面的毫米液滴可以通过与自身诱导波场的共振作用自我推进.这篇文章针对实验结果进行了综述,发现行走的液滴呈现出某些以往被认为只属于微观量子领域的特征.文章接着回顾... 详细信息

Yves Couder,Emmanuel Fort和同事们最近发现能够维持在振荡液体表面的毫米液滴可以通过与自身诱导波场的共振作用自我推进.这篇文章针对实验结果进行了综述,发现行走的液滴呈现出某些以往被认为只属于微观量子领域的特征.文章接着回顾了这种流体动力导航波系统的理论描述,从而深入了解其类量子行为的起源.量子化源于导波场施加在液滴上的动态约束,而多模态统计似乎是混沌导航波动力学的一个特征.在此,尝试评估此流体力学系统作为量子比拟的可能性和局限性.该流体力学系统与量子导航波理论的比较表明,他明显不同于玻姆力学,而与德布罗意(de Broglie)最初的量子动力学概念密切相关,这包括德布罗意的双解理论及其后研究者们在随机电动力学领域的拓展.

关键词：行走的液滴法拉第波量子比拟

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