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Stand dynamics of old-growth hemlock forests in central Bhutan are shaped by natural disturbances

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Forest Ecosystems 2024年第4期11卷 434-447页

作者： Karma Tenzin Craig R.Nitschke Kathryn J.allen Raphael Trouve Thiet v.Nguyen Patrick J.Baker School of Agriculture Foodand Ecosystem SciencesUniversity of Melbourne500 Yarra BlvdRichmondVictoriaAustralia School of Geography Planningand Spatial SciencesUniversity of TasmaniaSandy BayTasmaniaAustralia Forest Science Institute of South vietnam 1 Pham Van Hai StreetTan Binh DistrictHo Chi Minh CityViet Nam

Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future *** this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central *** of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over *** site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 *** both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance *** hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release *** 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer *** the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these *** variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development *** study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central *** also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management i

关键词： Forest structure Hemlock forest Himalaya Natural disturbance

Agronomy, Nutritional value, and Medicinal Application of Faba Bean(vicia faba L.)

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Horticultural Plant Journal 2019年第4期5卷 170-182页

作者： Fatemeh Etemadi masoud hashemi allen v.barker Omid Reza Zandvakili Xiaobing Liu Stockbridge School of Agriculture University of Massachusetts AmherstMA01003USA Northeast Institute of Geography and Agroecology Chinese Academy of SciencesHarbin150081China

Faba bean(vicia faba L.) is a cool season grain legume crop with the potential to be grown as multi-purpose crop in areas with short growing season. Faba bean is grown in many regions in the world due to its high nutritional value, medicinal effect, and effective biological nitrogen fixation. Diverse ecosystem benefits are expected from integrating faba bean in cropping systems. This paper specifically reviews the published work covering agronomic practices, nutritional values, medicinal benefits, and faba bean’s capacity for nitrogen fixation.

关键词： Biomass Faba bean L-Dopa Nitrogen fixation Nutrient

Utilizing an auxiliary portable lube oil heating system in Aliabad Katoul-Iran v94.2 gas turbine during standstill mode:a case study

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Propulsion and Power Research 2019年第4期8卷 320-328页

作者： H.Hasannejad Seyyed masoud Seyyedi M.hashemi-Tilehnoee Department of Mechanical Engineering Aliabad Katoul BranchIslamic Azad UniversityAliabad KatoulIran Young Researchers and Elite Club Aliabad Katoul BranchIslamic Azad UniversityAliabad KatoulIran

In a gas turbine power plant,the lubrication oil must be hot enough for the turbine start-up where the unit is in standstill ***,the strategy to heat the lubrication oil of ANSALDO v94.2 gas turbine power plant is operating the units in turning gear mode or interval ***,these strategies cause to suffering the power plant from high power consumption rate and *** this study,an auxiliary portable heating system was added to the unit 5 of the MAPNA built MGT-70(an Iranian version of v94.2)Aliabad Katoul-Iran power plant for increasing the lube oil ***,cost-effectiveness,and availability of the proposed heating system are studied by the concepts of exergy,economy,and reliability analyses,*** result of the exergy analysis shows that by using the auxiliary portable lube oil heating system the exergy destruction decreases about 94.7%and 92.6%in comparison with turning gear mode and interval mode,*** result of the economic analysis shows that the auxiliary portable heating system consumes less power rather than turning gear ***,it is a cost-effective system which has no penalty and no non-profit ***,the reliability analysis shows that the auxiliary portable lube oil heating system is a reliable tool during its lifetime.

关键词： Gas turbine Lube oil Lubrication system Portable heater Exergy Reliability

Analysis of the formation conditions and characteristics of interphase and random vanadium precipitation in a low-carbon steel during isothermal heat treatment

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International Journal of Minerals,Metallurgy and Materials 2018年第3期25卷 339-349页

作者： Sayed Ghafar hashemi B.Eghbali Department of Materials Engineering Sahand University of Technology

The characteristics of nanosized precipitates in steels depend on the heat-treatment parameters. The effects of characteristics of vanadium precipitates formed during isothermal heat treatment on the hardness of the ferrite matrix in low-carbon vanadium-alloyed steel were investigated through analysis of transmission electron microscopy images and microhardness measurements. The results show that, during isothermal holding in the temperature range from 675 to 750℃, only interphase precipitation occurs, whereas only random precipitation occurs in the ferrite matrix during holding at 600℃. Furthermore, during isothermal heat treatment between 600 and 675℃, both random and interphase precipitates occurred in the ferrite. Nanoscale vanadium carbides with different atomic ratios of vanadium(v) and carbon(C) were the dominant precipitates in the random and interphase precipitates. The sizes of random precipitation carbides were smaller than those of interphase ones. Also, the sample isothermally heat treated at 650℃ for 900s exhibited a higher hardness with a narrower hardness distribution.

关键词： low carbon steel vanadium carbide precipitation heat treatment microhardness

Simulating Raman spectra by combining first-principles and empirical potential approaches with application to defective MoS_(2)

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npj Computational Materials 2020年第1期6卷 1182-1188页

作者： Zhennan Kou Arsalan hashemi Martti J.Puska Arkady v.Krasheninnikov Hannu-Pekka Komsa Department of Applied Physics Aalto UniversityP.O.Box 1110000076 AaltoFinland Helmholtz-Zentrum Dresden-Rossendorf Institute of Ion Beam Physics and Materials Research01328 DresdenGermany Microelectronics Research Unit University of Oulu90014 OuluFinland

Successful application of two-dimensional transition metal dichalcogenides in optoelectronic,catalytic,or sensing devices heavily relies on the materials’quality,that is,the thickness uniformity,presence of grain boundaries,and the types and concentrations of point *** spectroscopy is a powerful and nondestructive tool to probe these factors but the interpretation of the spectra,especially the separation of different contributions,is not *** to simulated spectra is beneficial,but for defective systems first-principles simulations are often computationally too expensive due to the large sizes of the systems ***,we present a combined first-principles and empirical potential method for simulating Raman spectra of defective materials and apply it to monolayer MoS_(2) with random distributions of Mo and S *** study to what extent the types of vacancies can be distinguished and provide insight into the origin of different evolutions of Raman spectra upon increasing defect *** apply to our simulated spectra the phonon confinement model used in previous experiments to assess defect concentrations,and show that the simplest form of the model is insufficient to fully capture peak shapes,but a good match is obtained when the type of phonon confinement and the full phonon dispersion relation are accounted for.

关键词： spectra principles phonon

Effects of the level and source of dietary physically effective fiber on feed intake, nutrient utilization, heat energy, ruminal fermentation,and milk production by Alpine goats

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Animal Nutrition 2024年第2期17卷 312-324页

作者： Raquel v.Lourencon Amlan K.Patra Luana P.S.Ribeiro Ryszard Puchala Wei Wang Terry A.Gipson Arthur L.Goetsch American Institute for Goat Research Langston University

Thirty-two primiparous and 31 multiparous Alpine goats were used to determine influences of diets varying in level and source of forage on performance in early to mid-lactation for 16 wk. Diets consisted of 40%, 50%, 60%, and 70% forage(designated as 40F, 50F, 60F, and 70F, respectively) with 60F and 70F containing coarsely ground grass hay(primarily orchardgrass) and 40F and 50F containing cottonseed hulls, alfalfa pellets, and coarsely ground wheat hay. Diets contained 15.9% to 16.3% crude protein and37.8%, 42.1%, 53.5%, and 55.4% neutral detergent fiber(NDF) with 10.0%, 15.8%, 50.1%, and 55.5% particle retention on a 19-mm sieve, and 26.1%, 29.6%, 38.3%, and 40.0% physically effective NDF(pe NDF) for 40F,50F, 60F, and 70F, respectively. Dry matter intake(2.71, 2.75, 1.96, and 1.95 kg/d) and milk yield(2.82,2.71, 2.23, and 2.10 kg/d for 40F, 50F, 60F, and 70F, respectively) were lower(P er was similar among diets(P > 0.05), but digestibility of NDF was greater(P vely). Diet affected(P vely). Milk energy yield was greater(P ve to dry matter intake was not affected(P > 0.05) by diet and was lower(P vs. multiparous goats(2.71 and 3.09 MJ/kg). Ruminal p H and acetate proportion were greater for 60F and 70F than for the other diets and the proportion of butyrate was lower for the two diets highest in fiber. The mean lengths of time spent ruminating, eating, standing, and lying were not affected(P > 0.05) by diet or parity, but many interactions involving diet, period, hour, and parity were significant(P erformance o

关键词： Physically effective fiber Alpine goat Lactation Ruminal fermentation Feeding behavior

Nonclassical Lie symmetry and conservation laws of the nonlinear timefractional Korteweg–de vries equation

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Communications in Theoretical Physics 2021年第9期73卷 59-67页

作者： Mir Sajjad hashemi Ali Haji-Badali Farzaneh Alizadeh Mustafa Inc Department of Mathematics Basic Science FacultyUniversity of BonabBonabBox 55513-95133Iran Department of Computer Engineering Biruni UniversityIstanbulTurkey Department of Mathematics Science FacultyFirat University23119 ElazigTurkey Department of Medical Research China Medical University HospitalChina Medical UniversityTaichungTaiwanChina

In this paper,we use the symmetry of the Lie group analysis as one of the powerful tools that deals with the wide class of fractional order differential equations in the Riemann–Liouville *** this study,first,we employ the classical and nonclassical Lie symmetries(LS)to acquire similarity reductions of the nonlinear fractional far field Korteweg–de vries(Kdv)equation,and second,we find the related exact solutions for the derived ***,according to the LS generators acquired,we construct conservation laws for related classical and nonclassical vector fields of the fractional far field Kdv equation.

关键词： fractional equation Lie symmetry analysis classical and non-classical symmetries

Invariant G^(2)v algorithm for computing SAGBI-Grobner bases

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Science China Mathematics 2013年第9期56卷 1781-1794页

作者： hashemi Amir M.-ALIZADEH Benyamin RIAHI Monireh Department of Mathematical Sciences Isfahan University of Technology Young Researchers Club Science and Research BranchIslamic Azad University Department of Mathematics Damghan University

Faugère and Rahmany have presented the invariant F5 algorithm to compute SAGBI-Grbner bases of ideals of invariant rings. This algorithm has an incremental structure, and it is based on the matrix version of F5 algorithm to use F5 criterion to remove a part of useless reductions. Although this algorithm is more efficient than the Buchberger-like algorithm, however it does not use all the existing criteria (for an incremental structure) to detect superfluous reductions. In this paper, we consider a new algorithm, namely, invariant G2v algorithm, to compute SAGBI-Grbner bases of ideals of invariant rings using more criteria. This algorithm has a new structure and it is based on the G2v algorithm; a variant of the F5 algorithm to compute Grbner bases. We have implemented our new algorithm in Maple , and we give experimental comparison, via some examples, of performance of this algorithm with the invariant F5 algorithm.

关键词： G^(2)v algorithm invariant F5 algorithm invariant G^(2)v algorithm SAGBI-Grobner bases

An AlGaN/GaN HEMT with a reduced surface electric field and an improved breakdown voltage

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Chinese Physics B 2012年第8期21卷 360-364页

作者：谢刚 Edward Xu Niloufar hashemi 张波 Fred Y.Fu Wai Tung Ng The Edward S.Rogers Sr.Electrical and Computer Engineering Department University of Toronto State key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Crosslight Software Inc.Burnaby BCCanada

A reduced surface electric field in an AlGaN/GaN high electron mobility transistor （HEMT） is investigated by employing a localized Mg-doped layer under the two-dimensional electron gas （2-DEG） channel as an electric field shaping layer. The electric field strength around the gate edge is effectively relieved and the surface electric field is distributed evenly as compared with those of HEMTs with conventional source-connected field plate and double field plate structures with the same device physical dimensions. Compared with the HEMTs with conventional sourceconnected field plates and double field plates, the HEMT with a Mg-doped layer also shows that the breakdown location shifts from the surface of the gate edge to the bulk Mg-doped layer edge. By optimizing both the length of Mg-doped layer, Lm, and the doping concentration, a 5.5 times and 3 times the reduction in the peak electric field near the drain side gate edge is observed as compared with those of the HEMTs with source-connected field plate structure and double field plate structure, respectively. In a device with vGS = -5 v, Lm 1.5 m, a peak Mg doping concentration of 8×10^17 cm-3 and a drift region length of 10 m, the breakdown voltage is observed to increase from 560 v in a conventional device without field plate structure to over 900 v without any area overhead penalty.

关键词： AlGaN/GaN HEMT reduced surface electric field Mg-doped layer breakdown voltage