检索结果-南通市图书馆

A review of development of better prediction equations for blast fragmentation

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2019年第5期11卷 1094-1109页

作者： f.Ouchterlony J.A. Sanchidrián Department of Mining Engineering and Mineral Economics Montanuniversitaet Leoben Leoben Austria ETSI Minas Universidad Politécnica de Madrid Madrid Spain

The paper reviews the development of prediction formulas for the fragmentation from bench *** attention has been paid to the Kuz-Ram model,its development and errors,and the mean *** *** work by the US Bureau of Mines(USBM)and Chung and Katsabanis are also reviewed,as well as the two Julius Kruttschnitt Mineral Research Centre(JKMRC)models,*** crush zone model(CZM)and the two-component model(TCM),which were developed to cope with the underestimation of blasting *** change brought by the Swebrec distribution and the associated Kuznetsov-Cunningham-Ouchterlony(KCO)model is *** distribution-free fragment sizes xp for an arbitrary mass passing p led to the discovery of the fragmentation-energy fan,and with the help of dimensional analysis,to the new fragmentation prediction model xp-frag,which has much lower errors than those of the Kuz-Ram and CZM models.

关键词： Bench blasting Rock fragmentation fragmentation model Size distribution Swebrec function fragmentation-energy fan

nuclear reaction models and methods fusion reactions

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2016年第2期65卷 213-218页

作者： f.Lari O.n.Ghodsi Department of physics School of Sciences University of Mazandaran P.O. Box 47415-416 Babolsar Iran

The behaviors of barrier characteristics are analyzed for spherical-oblate systems over different configurations of colliding nuclei. for this purpose, we have extended our previous study [phys. Rev. C 89（2014） 054607], it is devoted to optimum ＂cold＂ and ＂hot＂ configuration] to analyze the same reaction systems in various *** investigation on some chosen systems reveals that the barrier height and its position can be parameterized in times of the different orientations.

关键词： parametrization of Barrier Characteristics for Spherical-Oblate Systems in any Configuration of Colliding nuclei

Data Driven Modelling of Coronavirus Spread in Spain

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第9期64卷 1343-1357页

作者： G.n.Baltas f.A.prieto M.frantzi C.R.Garcia-Alonso p.Rodriguez Loyola Institute of Science and Technology Universidad Loyola AndalucíaSeville41704Spain Department of Biomarker Research Mosaiques Diagnostics GmbHHannover30659Germany Renewable Electrical Energy Systems Technical University of CataloniaTerrassa08222Spain

During the late months of last year,a novel coronavirus was detected in Hubei,*** virus,since then,has spread all across the globe forcing Word Health Organization(WHO)to declare COVID-19 outbreak a *** Spain,the virus started infecting the country slowly until rapid growth of infected people occurred in Madrid,Barcelona and other major *** government in an attempt to stop the rapssid spread of the virus and ensure that health system will not reach its capacity,implement strict measures by putting the entire country in *** duration of these measures,depends on the evolution of the virus in *** this study,a Deep neural network approach using Monte Carlo is proposed for generating a database to train networks for estimating the optimal parameters of a SIR epidemiology *** number of total infected people as of April 7 in Spain is considered as input to the Deep neural *** adaptability of the model was evaluated using the latest data upon completion of this paper,i.e.,April *** date range for the peak of infected people(i.e.,active cases)based on the new information is estimated to be within 74 to 109 days after the first recorded case of COVID-19 in *** addition,a curve fitting measure based on the squared Euclidean distance indicates that according to the current data the peak might occur before the 86th ***,Deep neural networks have proven accurate and useful tools in handling big epidemiological data and for peak prediction estimates.

关键词： Coronavirus deep neural network machine learning Monte Carlo simulation SIR model

numerical solutions for cracks in an elastic half-plane

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第1期35卷 212-227,I0006页

作者： n.R.f.Elfakhakhre n.M.A.nik Long Z.K.Eshkuvatov Mathematics Department Faculty of ScienceUniversiti Putra Malaysia43400 SerdangSelangorMalaysia Institute for Mathematical Research Universiti Putra Malaysia43400 SerdangSelangorMalaysia faculty of Science and Technology Universiti Sains Islam Malaysia71800 NilaiNegeri SembilanMalaysia

The behavior of the stress intensity factor at the tips of cracks subjected to uniaxial tension σχ^∞= p with traction-free boundary condition in half-plane elasticity is investigated. The problem is formulated into singular integral equations with the distribution dislocation function as unknown. In the formulation, we make used of a modified complex potential. Based on the appropriate quadrature formulas together with a suitable choice of collocation points, the singular integral equations are reduced to a system of linear equations for the unknown coefficients. numerical examples show that the values of the stress intensity factor are influenced by the distance from the cracks to the boundary of the half-plane and the configuration of the cracks.

关键词： Elastic half-plane Multiple cracks Singular integral equation Sine-shaped crack

Creep behavior of AJ62 Magnesium-Aluminum-Strontium alloy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2020年第2期8卷 414-420页

作者： f.Dobes p.Dymacek CEITEC IpM Institute of Physics of Materials CASZizkova 22.61662 BrnoCzech Republic

Creep tests were conducted in uniaxial compression to evaluate the creep behavior of magnesium-aluminum-strontium alloy at temperatures from 373 to 673 *** dependencies of the creep rate over the whole interval of temperatures and stresses can be well described phenomenologically by the Garofalo sine hyperbolic equation modified by the inclusion of a threshold *** threshold stress increases with decreasing *** data normalized by a diffusion coefficient and shear modulus clearly reveal the existence of two different *** mechanisms by which plastic deformation takes place have been identified in both *** critical stress at which dislocations break away from the cloud of foreign atoms agrees well with the value determined by data *** low stresses,a value of the stress exponent of n≈=3 is consistent with the model of deformation that takes place through dislocation glide controlled by dragging of solute *** high stresses,the multiple regression yields the activation energy which agrees with that for prismatic glide.

关键词： Dislocations Diffusion Mechanical properties Creep

Octreotide ameliorates gastric lesions in chronically mild stressed rats

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2011年第9期17卷 1135-1142页

作者： noha n nassar Mona f Schaalan Hala f Zaki Dalaal M Abdallah Department of pharmacology and Toxicology Faculty of PharmacyCairo University Department of Biochemistry Faculty of PharmacyMisr International University

AIM:To evaluate the effect of chronic mild stress(CMS) on the emergence of gastric ulcers and possible modulation by octreotide,a synthetic somatostatin analogue. METHODS:Adult male Wistar rats were subjected to nine different unpredictable random stress procedures for 21 d,a multifactorial interactional animal model for *** was administered daily for 21 d at two dose levels(50 and 90μg/kg)before exposure to stress ***-and microscopical assessments were made,in addition to quantification of plasma corticosterone and gastric mucosal inflammatory,oxidative stress, and apoptotic biomarkers. RESULTS:Exposure to CMS elevated plasma corticosterone(28.3±0.6μg/dL,p=0.002),an event that was accompanied by gastric lesions(6.4±0.16 mm,p=0.01) and confirmed ***,the insult elevated gastric mucosal lipid peroxides(13±0.5 nmol/g tissue,p=0.001),tumor necrosis factor-α(3008.6±78.18 pg/g tissue,pprostaglandin E2(117.1 ±4.31 pg/g tissue,p=0.002),and caspase-3 activity (2.4±0.14 OD/mg protein,p=0.002).Conversely,CMS mitigated interleukin-10(627.9±12.82 pg/g tissue,p= 0.001).furthermore,in animals exposed to CMS,octreotide restored plasma corticosterone(61%and 71%from CMS,p=0.002)at both dose *** beneficial effects were associated with a remarkable suppression of gastric lesions(38%and 9%from CMS,p=0.01)and reversal of derangements in gastric mucosa. COnCLUSIOn:The current investigation provides evidence that exposure to CMS induces gastric ulceration, which was alleviated by administration of octreotide possibly possessing antioxidant,anti-inflammatory,and anti-apoptotic actions.

关键词： Gastric ulcer Chronic mild stress Octreotide Inflammation Oxidative stress Apoptosis Histopathology

Localization of polycyclic aromatic hydrocarbons and heavy metals in surface soil of Asia’s oldest oil and gas drilling site in Assam,northeast India:Implications for the bio-economy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Emerging Contaminants 2016年第3期2卷 119-127页

作者： Hemen Sarma n.f.Islam p.Borgohain A.Sarma M.n.V.prasad Department of Botany N N Saikia CollegeTitabarAssamIndia Department of Biotechnology Pandu CollegeGuwahatiAssamIndia Department of plant Science University of HyderabadHyderabadTelanganaIndia

The environmental influx of hazardous contaminants viz pAHs and HMs occurs due to oil and gas drilling,and processing of petroleum products in industrial facilities and *** problem plagues crude oil drilling sites as pAHs are an essential component of and HMs coexist with crude *** analyzed the spatial distribution of 16 pAHs and 8 HMs in 10 contaminated sites of Assam,a state in *** included Digboi,where crude oil was drilled in 1867 and the first oil well in Asia that was ***Ʃ16 pAHs in soil were detected with a minimum of 13.48 and a maximum of 86.3 mgkg1 andƩ8 heavy metal concentrations in the soil ranged between 69.51 and 336.06 mgkg1.A negative correlation was detected between the relative concentrations of pAHs and *** results confirmed that the nonbiodegradable nature of HMs made them stay in the soil for longer periods of *** our study,we found that the levels of lead,copper,nickel,and chromium(total)in soil were 73.62,11.86,58.97 and 158.66 mgkg*** recovery percentage for pAHs and HMs were in the range of 67e97%and 90e95%*** distribution indices for phenanthrene/Anthracene,naphthalene/Acenapthhylene,Chyrsene/Benzo(g,h,i)perylene and fluranthene/pyrene)calculated for soil samples indicated that the spatial distribution of pAHs in soil is uneven which might be due to variations in contaminates disseminated in *** regionalized concentration has serious implications on the bio-economy both in terms of health and economy,especially since the proximity of crude oil sites to paddy fields and/or tea plantations uniquely marks the landscape of upper Assam.

关键词： pAH Heavy metals Spatial distribution indices Oil Drilling site

pr(Ⅲ) and nd(Ⅲ) Absorption Spectroscopic probe to Investigate Interaction with Lysozyme (HEW)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第6期24卷 648-652页

作者： Jignasu p.Mehta prashant n.Bhatt Sudhindra n. Misra Department of Chemistry Bhavnagar UniversityBhavnagar-364002India

pr（ Ⅲ ） and nd（ Ⅲ ） can be utilized as absorption spectroscopic probes to investigate the interaction of biomolecules like Lysozyme （HEW） with Ca（ Ⅱ ） in-vitro ; the most abundant metal ion in the human body system. The spectroscopic techniques involving comparative absorption, absorption difference, and quantitative intensity analysis using 4f-4f transitions are utilized for changes in the inner sphere coordination pattern of pr（ Ⅲ ） and nd（Ⅲ ） in solution as well as in solid state. The present study deals with an important biomolecule in human metabolism, that is, Lysozyme （HEW）. The absorption er-Condon the probab spectral parameters such as the oscillator strength （p）, the Judd-Ofelt （Tλ） intensity parameters, and the Slatinter electronic parameters are calculated using chi square methods. The obtained results are used to determine le geometry of the complex in the solution, the nature of the bond between pr（Ⅲ）/nd（Ⅲ） with lysozyme, and the inner sphere coordination environment of f-f transitions. The results obtained from various experimental conditions are utilized to investigate the coordination changes in the pr（Ⅲ）/nd（Ⅲ） complexes caused by different coordinating sites of lysozyme, normalized bite, denticity, the solvent nature, the coordination number, the nature of bond and other parameters to mimic the interaction of the Ca（ Ⅱ ） ion with such biomolecule.

关键词： absorption spectra pr(Ⅲ), nd(Ⅲ) Lysozyme (HEW) spectral parameters rare earths

Dating Magmatic Hornblende and Biotite and Hydrothermal Sericite by Laser probe Technique:Constraints on Genesis of Wangershan Gold Deposit,Eastern Shandong province,China

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2003年第4期 50-59页

作者： Vasconcelos p M,Zhou M f,Duzgoren-Aydin n S Department of Earth Sciences The University of Queensland Department of Earth Sciences The University of Hong Kong Department of Earth Sciences The University of Hong Kong Brisbane 4072 Australia pokfulam Hong Kong pokfulam Hong Kong

The Wangershan gold deposit and spatially related Shangzhuang granite, eastern Shandong province, have been precisely dated by 40 Ar/ 39 Ar laser incremental heating technique. Magmatic hornblende and biotite, collected from the Shangzhuang granites, yielded well-defined and reproducible plateau ages at 128.1-127.5 and 124.4-124.1 Ma (2 σ ), measuring the cooling ages of the intrusion at ca. 500 ℃ and 300-350 ℃, respectively. Hydrothermal sericite extracted from auriferous vein gave high-quality plateau ages between (120.6±0.3) Ma and (120.0±0.4) Ma (2 σ ). Given the similarity of the closure temperature for argon diffusion (300-350 ℃) in the sericite mineral to the homogenization temperature of primary fluid inclusions in the quartz from gold ores, and the intergrowth of sericite with native gold, present 40 Ar/ 39 Ar sericite ages can be reliably interpreted in terms of the mineralization age for the Wangershan deposit. 40 Ar/ 39 Ar hornblende and biotite ages permit an estimate for the cooling rate of the Shangzhuang granite at about 50 ℃/Ma. There are abundant intermediate-mafic dikes in most gold camps of eastern Shandong, whose ages of formation have been previously constrained mainly at 121-119 Ma. The temporal association between the Shangzhuang granite, the Wangershan gold deposit, and the widespread dikes confirms that intrusive activity, gold mineralization, and dike emplacement in this region were broadly coeval, reflecting significant continental lithosphere thinning and resulting crustal extension of Early Cretaceous in eastern China.

关键词： 40Ar/39 Ar dating cooling age magmatism mineralization Wangershan gold deposit.