检索结果-南通市图书馆

Tree species composition and diversity in montane forests of Garhwal Himalaya in relation to environmental and soil properties

引用

Journal of Mountain Science 2020年第12期17卷 3097-3111页

作者： Dinesh Singh RAWAT P.TIWARI sudipta kumar das J.K.TIWARI Department of Botany&Microbiology HNB Garhwal UniversitySrinagar(Garhwal)-246174UttarakhandIndia Central National Herbarium Botanical Survey of IndiaHowrah-711103West BengalIndia

The montane forests of Garhwal Himalaya were investigated for tree species composition and diversity in relation to environmental and edaphic variables.A stratified random sampling approach was adopted to collect the field data from each forest.A total of 39 tree species belonging to 31 genera and 23 families were recorded from the sampling area(6 forest stands ×10 plots in each).Lauraceae with 5 species was the largest family while Quercus(4 species) emerged as the largest ***-area curve(asymptote) predicted more species than the observed number of *** analysis has shown that the two Abies pindrow dominant forest stands had the highest similarity in tree species *** tree stem density ranged from 540-1170 ha-1,basal area 23.01-55.94 m^2 ha-1,ShannonWiener diversity index 1.69-2.49,evenness index0.42-0.74,beta diversity 0.40-0.82 and similarity index 0.17-0.54 in the six studied ***-way indicator species analysis(TWINSPAN) identified four distinct tree communities in the study area with Daphniphyllum himalayense,Abies pindrow,Quercus oblongata,and Pinus roxburghii as indicator species of corresponding *** correspondence analysis(CCA) ascertained the TWINSPAN results and revealed the relation of tree species with environmental and edaphic *** phytosociological attributes of tree species varied from one forest stand to another;however,the tree species richness,density,and diversity peaked at intermediate elevation on the north *** reveal that tree composition and diversity in the montane forests of Garhwal Himalaya are influenced by both environmental(elevation and slope aspect)and soil variables(texture,water holding capacity,moisture content,available N,exchangeable P,and pH).This study will help in understanding the forest distribution across the western Himalaya,guiding the conservationists and policymakers in carrying out conservation-related management activities,designing the long-

关键词： Diversity Tree species Montane forests Soil properties Western Himalaya

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A new parametrization of dark energy equation of state leading to double exponential potential

引用

Research in Astronomy and Astrophysics 2018年第11期18卷 1-10页

作者： sudipta das Abdulla Al Mamon Manisha Banerjee Department of Physics Visva-Bharati Department of Mathematics Jadavpur University

We show that a phenomenological form of energy density for the scalar field can provide the required transition from decelerated(q > 0) to accelerated expansion(q < 0) phase of the *** have used the latest type Ia supernova(SNIa) and Hubble parameter datasets to constrain the model parameters. The best fit values obtained from those datasets are then applied to reconstruct ωφ(z), the equation of state parameter for the scalar field. The results show that the reconstructed forms of q(z) and ωφ(z) do not differ much from the standard ΛCDM value at the current epoch. Finally, the functional form of the relevant potential V(φ) is derived by a parametric reconstruction. The corresponding V(φ)comes out to be a double exponential potential, which has a number of cosmological ***, we have also studied the effect of this particular scalar field dark energy sector on the evolution of matter overdensities.

关键词： cosmic acceleration quintessence field dark energy density perturbation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Visible Light Excitable SCN^- Selective Fluorescence Probe Derived from Thiophene

引用

Chinese Journal of Chemistry 2015年第10期33卷 1173-1177页

作者： sudipta das Sisir Lohar Jesus Sanmartin Matalobos Debasis das Department of Chemistry The University of Burdwan Burdwan 713104 West Bengal India Departamento de Qu'tmicalnorg'anica Facultade de Qutmica Avda. Das Ciencias s/n 15782 Santiago de Compostela Spain

An efficient fluorescence probe, 4-methyl-2,6-bis（（thiophen-2-ylmethylimino）methyl）phenol （DFPTMA） and its SCN adduct has been synthesized and characterized by different spectroscopic techniques like ^1H NMR,^13C NMR, QTOF-MS ES^＋, UV-Vis and FTIR spectroscopy. Single crystal X-ray structure of DFPTMA is reported. In presence of SCN-, DFPTMA exhibits significant fluorescence enhancement （λEx, 455 nm, λEm, 504 nm） in aqueous methanol （water-methanol, 1 ： 4, V/V, 0.1 mol/L HEPES buffer, pH 7.4）. Common bio-relevant anions viz. CH3COO^-, NO2, NO7, Cl^-, Br^-, I^-, SO4^2-, HSO4^-, N3^-, HAsO4^2-, Cr2O7^2-, H2PO4, ClO4^-, NCO^-, CN^-, CO3^2-, F^-, PO4^3-, S2-, HS- do not interfere in the recognition of SCN-. Lowest detection limit for SCN^- is 0.88 μmol/L with response time 〈5 min. The SCN assisted enhancement in emission intensity may be attributed to the formation of H-bond which enhances the rigidity of the molecular assembly.

关键词： visible light excitation SCN^- fluorescence thiophene derivative

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Trace fossil evidences of an Early Miocene paleoseismic event and depositional regime change from the Kutch(Kachchh) Basin

引用

Journal of Palaeogeography 2024年第1期13卷 165-180页

作者： Ayush Srivastava sudipta dasgupta Krishanu Chatterjee Mohuli das Bombay Ichnos Research Group Department of Earth SciencesIndian Institute of Technology Bombay(lIT Bombay)PowaiMumbaiMaharashtra400076India

Unconsolidated siliciclastic sediments can undergo post-burial deformation, which leads to the formation of distinctive sedimentary structures, known as soft-sediment deformation structures(SSDS). The presence of a series of sand volcanoes confined to a particular lithostratigraphic horizon can represent a paleoseismic activity and, thereby, exemplifies the concept of “seismite”. The Kutch Basin has been a tectonically active region since the initiation of eastern Gondwana rifting followed by a tectonic inversion during the Cenozoic due to the collision of the Indian and Eurasian plates. A stratum-bound series of sand volcanoes belonging to the Khari Nadi Formation(KNF) is exposed along the banks of Khari River. They separate the shallow marine deposits below and non-marine deposits above with their characteristic marine and paleosol trace fossil suites, respectively. Although a seismogenic origin has been much debated for the SSDS,the ichnofabric analysis of the sand-volcano-bearing stratum unequivocally points toward such an origin under a shallow seafloor condition. In addition to the sedimentary regime change from an open shallow-marine setting to a continental depositional environment concomitant with basinal uplift, the behavior of the burrowing crustaceans testifies to a syn-depositional development of a fault network associated with the fluidization, sand volcanism, and the resilience of the trace-producers in surviving those processes until the sedimentary regime change in the overlying strata. Although the ichno-sedimentological evidence apparently differs from the previous works that proposed a continuous base-level rise from the beginning of deposition of the Khari Nadi Formation up to the middle part of the overlying Chhasra Formation, the paleoseismic activity,its ichnologic signature, and the depositional regime change refer to a higher-resolution(i.e., lower-order)sequence-stratigraphic change causing a short-duration regression within a longer-durat

关键词： Sand volcano Seismite Ichnology Khari Nadi Formation Kutch Basin Kachchh Basin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

H_(∞) Load Frequency Control Design Based on Delay Discretization Approach for Interconnected Power Systems with Time Delay

引用

Journal of Modern Power Systems and Clean Energy 2021年第6期9卷 1468-1477页

作者： Subrat kumar Pradhan Dushmanta kumar das Department of Electrical and Electronics Engineering National Institute of Technology Nagaland

This paper proposes a delay discretization based H∞load frequency control strategy for interconnected power *** effect of time delay is considered in the system for the design of stabilizing *** improve the tolerable delay margin of the system,a two-term state feedback controller structure is *** controller requires delayed state information as control *** the proposed approach,the amount of delay introduced in the state of the system,i.e.,artificial delay,for taking control action is assumed to be *** approach is based on the discretization of this delay *** order to define a simple Lyapunov-Krasovskii(LK)function for each of the discretized interval,a stabilization criterion is developed in such a way that a single one satisfies the requirement of all the *** developed criterion is computationally simple and efficient.

关键词： Interconnected power system load frequency control(LFC) state feedback controller time delay

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Powder mixed electrochemical discharge process for micro machining of C103 niobium alloy

引用

Defence Technology（防务技术） 2023年第8期26卷 84-101页

作者： Niladri Mandal Nitesh kumar Alok kumar das Defence Research&Development Laboratory(DRDL)-DRDO HyderabadIndia Department of Mechanical Engineering Indian Institute of Technology(ISM)DhanbadIndia

This work demonstrates the viability of the powder-mixed micro-electrochemical discharge machining(PMECDM) process to fabricate micro-holes on C103 niobium-based alloy for high temperature *** processes are involved simultaneously *** erosion,chemical etching,and abrasive grinding for removal of material while the classical electrochemical discharge machining process involves double actions *** erosion,and chemical *** powder-mixed electrolyte process resulted in rapid material removal along with a better surface finish as compared to the classical microelectrochemical discharge machining(MECDM).Further,the results are optimized through a multiobjective optimization approach and study of the surface topography of the hole wall surface obtained at optimized *** the selected range of experimental parameters,PMECDM shows a higher material removal rate(MRR) and lower surface roughness(R_(a))(MRR:2.8 mg/min and R_(a) of 0.61 μm) as compared to the MECDM process(MRR:2.01 mg/min and corresponding Raof 1.11 μm).A detailed analysis of the results is presented in this paper.

关键词： Micro-electrochemical discharge machining C103 niobium alloy Surface integrity Material removal rate Hybrid powder mixed ECDM

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An improved brain MR image binarization method as a preprocessing for abnormality detection and features extraction

引用

Frontiers of Computer Science 2017年第4期11卷 717-727页

作者： sudipta ROY Debnath BHATTACHARYYA Samir kumar BANDYOPADHYAY Tai-Hoon KIM Department of Computer Science and Engineering Institute of Computer Technology (UVPCE) Ganpat University Ahmadabad 380060 India Information Technology Department College of Engineering Bharati Vidyapeeth deemed University Pune 411043 India Department of Computer Science and Engineering University of Calcutta Technology Campus Kolkata 700098 India Department of Convergence Security Sungshin Women's University Seoul 136-742 Korea

This paper propose a computerized method of magnetic resonance imaging （MR/） of brain binarization for the uses of preprocessing of features extraction and brain ab- normality identification. One of the main problems of MR/ binarization is that many pixels of brain part cannot be cor- rectly binarized due to extensive black background or large variation in contrast between background and foreground of MR/. We have proposed a binarization that uses mean, vari- ance, standard deviation and entropy to determine a thresh- old value followed by a non-gamut enhancement which can overcome the binarization problem of brain component. The proposed binarization technique is extensively tested with a variety of MR/and generates good binarization with im- proved accuracy and reduced error. A comparison is carried out among the obtained outcome with this innovative method with respect to other well-known methods.

关键词： image binarization thresholding image pre-processing segmentation performance analysis accuracy es-timation MRI of brain entropy

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Cocktail of Natural Compounds Holds Promise for New Immunotherapeutic Potential in Head and Neck Cancer

引用

Chinese Journal of Integrative Medicine 2024年第1期30卷 42-51页

作者： Sunil kumar Asmita das Department of Biotechnology Delhi Technological UniversityDelhi(110042)India

Objective: To obtain detailed understanding on the gene regulation of natural compounds in altering prognosis of head and neck squamous cell carcinomas(HNSC). Methods: Gene expression data of HNSC samples and peripheral blood mononuclear cells(PBMCs) of HNSC patients were collected from Gene Expression Omnibus(GEO). Differential gene expression analysis of GEO datasets were achieved by the GEO2R tool. Common differentially expressed gerres(DEGs) were screened by comparing DEGs of HNSC with those of PBMCs. The combination was further analyzed for regulating pathways and biological processes that were affected. Results: Totally 110 DEGs were retrieved and identified to be involved in biological processes related to tumor regulation. Then 102 natural compounds were screened for a combination such that the expressions of all 110 commonly DEGs were altered. A combination of salidroside, ginsenoside Rd, oridonin, britanin, and scutellarein was chosen. A multifaceted, multi-dimensional tumor regression was showed by altering autophagy, apoptosis, inhibiting cell proliferation, angiogenesis, metastasis and inflammatory cytokines production. Conclusions: This study has helped develop a unique combination of natural compounds that will markedly reduce the propensity of development of drug resistance in tumors and immune evasion by tumors. The result is crucial to developing a combinatorial natural therapeutic cocktail with accentuated immunotherapeutic potential.

关键词： natural compounds chemopreventive gene expression head and neck cancer immunomodulator salidroside ginsenoside Rd oridonin britanin scutellarein

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis and design of open trench barriers in screening steady-state surface vibrations

引用

Earthquake Engineering and Engineering Vibration 2014年第3期13卷 545-554页

作者： Ankurjyoti Saikia Utpal kumar das Department of Civil Engineering Tezpur University

The problem of vibration isolation by rectangular open trenches in a plane strain context is numerically studied using a finite element code, PLAXIS. The soil media is assumed to be linear elastic, isotropic, and homogeneous subjected to a vertical harmonic load producing steady-state vibration. The present model is validated by comparing it with previously published works. The key geometrical features of a trench, i.e., its depth, width, and distance from the source of excitation, are normalized with respect to the Rayleigh wavelength. The attenuation of vertical and horizontal components of vibration is studied for various trench dimensions against trench locations varied from an active to a passive case. Results are depicted in non-dimensional forms and conclusions are drawn regarding the effects of geometrical parameters in attenuating vertical and horizontal vibration components. The screening efficiency is primarily governed by the normalized depth of the barrier. The effect of width has little significance except in some specific cases. Simplified regression models are developed to estimate average amplitude reduction factors. The models applicable to vertical vibration cases are found to be in excellent agreement with previously published results.

关键词： finite element open trench vibration isolation wave barrier non-dimensional

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Electrochemically functionalized graphene as an anti-corrosion reinforcement in Cu matrix composite thin films

引用

International Journal of Minerals,Metallurgy and Materials 2021年第9期28卷 1525-1533页

作者： Akhya kumar Behera Amlan das Sanjeev das Archana Mallik Electrometallurgy and Corrosion Laboratory(Research) Department of Metallurgical and Materials EngineeringNational Institute of TechnologyRourkela 769008OdishaIndia Advanced Metal Casting Laboratory Department of Metallurgical and Materials EngineeringNational Institute of TechnologyRaipur 492010ChhatisgarhIndia

Cu-graphene(Gr)composite thin films were prepared by electrodeposition route using in-house synthesized Gr *** Gr sheets were synthesized by the electrochemical exfoliation route using 1 M HClO4 acid as *** Gr sheets were confirmed by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field-emission scanning electron microscopy(FESEM),and transmission electron microscopy(TEM).The(002)plane of Gr sheets was observed at 2θof 25.66°.The(002)plane confirmed the crystal structure of car-bon *** stretching vibration of C=C bond at a wavelength of 1577 cm^(−1) and other functional groups of carboxyl and epoxide groups were observed from *** confirmed the transparent structure of Gr *** prepared Gr sheets were used as reinforcement at con-centrations of 0.1 and 0.3 g/L with a copper matrix to synthesize the Cu-Gr *** prepared composite thin films were characterized by XRD,SEM,and energy-dispersion spectrometry(EDS)for morphological and analytical *** presence of Gr sheets in Cu-Gr com-posite was confirmed by EDS *** prepared Cu-Gr nanocomposite thin film showed higher corrosion resistance compared with pure copper thin films in 3.5wt%NaCl,as confirmed by Tafel *** impedance spectroscopy complimented the above results and showed that 0.3 g/L composite film achieved the highest film resistance.

关键词： graphene nanocomposite electrodeposition copper

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：