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Production and characterization of ZnO nanoparticles and porous particles by ultrasonic spray pyrolysis using a zinc nitrate precursor

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International Journal of Minerals,Metallurgy and Materials 2012年第7期19卷 651-656页

作者： Burak Ebin Elif Arτg Burak zkal Sebahattin gürmen Metallurgical & Materials Engineering Department Istanbul Technical University

ZnO nanoparticles and porous particles were produced by an ultrasonic spray pyrolysis method using a zinc nitrate precursor at various temperatures under air atmosphere. The effects of reaction temperature on the size and morphology of ZnO particles were investi- gated. The samples were characterized by energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. ZnO particles were obtained in a hexagonal crystal structure and the crystallite shapes changed from spherical to hex- agonal by elevating the reaction temperature. The crystallite size grew by increasing the temperature, in spite of reducing the residence time in the heated zone. ZnO nanoparticles were obtained at the lowest reaction temperature and ZnO porous particles, formed by aggregation of ZnO nanoparticles due to effective sintering, were prepared at higher temperatures. The results showed that the properties of ZnO particles can be controlled by changing the reaction temperature in the ultrasonic spray pyrolysis method.

关键词： zinc oxide nanoparticles nanocrystallites porous materials ultrasonic applications spray pyrolysis

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Status of KLOE-2

Chinese Physics C 2010年第6期34卷 918-923页

作者： g.Venanzoni Laboratori Nazionali di Frascati dell'INFN

In a few months the KLOE-2 detector is expected to start data taking at the upgraded DAФNE φ-factory of INFN Laboratori Nazionali di Frascati. It aims to collect 25 fb^-1 at the φ（1020） peak, and about 5 fb^-1 in... 详细信息

关键词： electron-positron annihilation φ-factory kaon interferometry discrete symmetries γγ physics scalar spectroscopy hadronic cross sections g-2 αem

An approach for optimization of the wall thickness (weight) of a thick-walled cylinder under axially non-uniform internal service pressure distribution

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Defence Technology（防务技术） 2017年第3期13卷 150-157页

作者： Onur güngor MKE Kurumu Mühimmat Fabrikas Ar-ge Müdürlügü 71100 Merkez

Today, improving the weight/load carrying capacity ratio of a part is the matter of studies in most of the scientific and industrial *** dimensions, the amount of material removed from outer and inner radius while manufacturing and the service pressure applied affect the residual stress distribution throughout the wall thickness and hence the load-bearing capacity of a thick-walled cylinder. Calculation of residual stresses after autofrettage process and optimization of autofrettage outline dimensions by using the amount of service pressures applied are common issues in *** this study, mandrel-cylinder tube interference dimensions were renovated by using traditional methods for swage autofrettage process of a gun barrel. Also, the residual stresses in the cylinder after autofrettage process, inside and outside material removal process and the variable service pressure throughout the cylinder applied were taken into consideration and incorporated into the design. By using the constrained optimization method, wall thickness(thus the weight) was optimized(minimized)to achieve the specified safety factor along the length of the cylinder. For the same cylinder, the results of the suggested analytical/with residual stress calculation approach were compared to analytical/without residual stress calculation results and numerical topology optimization method calculation results. Since the experimental measurement results are not yet available, it was not possible to compare them with the calculation *** suggested approach enabled 22.9% extra weight reduction in proportion to numerical topology optimization and enabled 4.2% extra weight reduction in proportion to analytical/without residual stress *** this approach, the gain from residual stresses after autofrettage operation, the loss of residual stresses after material removal, and the effects of service pressures can be taken into account for each stage of design.

关键词：尺寸优化圆筒壁厚厚壁圆筒载重量残余应力分析非均匀应力计算方法自增强材料

Retzius-sparing robotic radical prostatectomy

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Asian Journal of Andrology 2020年第2期22卷 149-151页

作者： Christopher g Eden Department of Urology The Royal Surrey County HospitalGuildford GU27XXUK

Traditional approach to the prostate during radical prostatectomy(RP)when performed by open,laparoscopic,or robotic means has been from its anterior aspect first and has involved suture ligation and division of the dorsal vein complex(DVC),division of the puboprostatic ligaments,and incision of the endopelvic fascia on either side of the *** steps are necessary to liberate the prostate from its surrounding attachments,even though concern has always existed about the likely association between disruption of these structures and postprostatectomy incontinence(PPI).Although perineal prostatectomy leaves these structures intact,it has failed to become widely accepted because of the small incidence of postoperative fecal incontinence and the difficulty in performing a pelvic lymphadenectomy(PLND)when this is indicated.

关键词： robotic radical steps

Morphology and distribution of Pronoctiluca (Dinoflagellata, incertae sedis) in the Pacific Ocean

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Acta Oceanologica Sinica 2013年第4期32卷 71-76页

作者： góMEZ Fernando Department of Biological Oceanography Institute of Oceanography University of S o Paulo

The diversity and distribution of Pronoctiluca, a marine dinoflagellate of enigmatic systematic position, was studied in the vicinity of the Kuroshio and Oyashio Currents, the Philippines, Celebes, Sulu and South China Seas, western and central equatorial and southeast Pacific Ocean. The abundance of Pronoctiluca was high- er, with a wide vertical distribution, in eutrophic temperate regions, whereas it was nearly absent in surface waters of oligotrophic tropical regions. Most of the specimens corresponded to P. spinifera. Pronoctiluca pelagica, covered by hyaline layers and with no flagella, is considered as an encysted form. The bipartition was only observed in P. acuta-P, spinifera forms, that together with the occurrence of intermediate forms between P. spinifera and P. pelagica suggest that they may correspond to developmental stages of a single species. Pronoctiluca is essential to understanding the evolutionary history of the alveolates.

关键词： Alveolata basal dinoflagellates Dinophyceae heterotrophic flagellate Noctilucales plankton

Fluidity and Temperature Profile of Ductile Iron in Thin Sections

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Journal of Iron and Steel Research International 2012年第8期19卷 52-59页

作者： Marcin górny Department of Cast Alloys and Composites Engineering AGH University of Science and Technology

It has been shown that it is possible to produce thin wall ductile iron (TWDI) castings of considerable length using an Archimedes spirals with a wall of 1, 2 or 3 mm in thickness. The fluidities for different moulding materials [(classical mould, chemically bonded silica sand and chemically bonded low-density alumina-silicate ceramic sand (LDASC)], chemical composition, and pouring temperature were estimated. There is a significant temperature drop in thin sections (contrary to typical sections) during the mould filling. A profile of real temperature drop is presented along with theoretical predictions. The high temperature drop of liquid iron results in an increased cooling rate (before the eutectic equilibrium solidification temperature), which in turn affects the solidification and microstructure of TWDI castings. Microstructures were characterized quantitatively using an image analyser. Structure parameters for different wall thicknesses and moulding materials (graphite nodule count, ferrite and cementite fraction) are plotted, which is versus distance from the entrance to the mould cavity. It has been shown that the thin wall castings have a gradient structure. Moreover, a strong influence of LDASC sand (material with low ability to absorb the heat) on the structure parameters of TWDI castings is presented.

关键词： fluidity ductile iron thin wall casting Archimedes spiral

Breakdown process on rod–rod air gap under oscillating lightning impulse voltage

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High Voltage 2020年第3期5卷 319-326页

作者： Akif gürlek Faculty of Electrical Engineering and Information Technology Professorship of Power Systems and High-Voltage EngineeringTechnische Unversität ChemnitzReichenhainer Strasse 70D-09126 ChemnitzGermany

This study presents the discharge process on rod–rod electrodes under oscillating lightning impulse *** this purpose,a measurement system has been developed to record the discharge currents at both rod electrodes simultaneously and to photograph the spatial propagation of the *** measurement results of the discharge process are shown for an air gap of s=150 cm and for a superimposed frequency of f=200 *** the standardised lightning impulse voltage,three consecutive phases of discharge have been identified before a breakdown *** are streamer discharge phase,channel transition phase and channel formation *** three phases are described,interpreted and their correlation is *** the basis of the oscillations,the discharge processes recur periodically if the momentary voltage is higher than the mean curve of the oscillating lightning impulse *** streamer discharge emerges foremost at the positive rod electrode and propagates toward the grounded rod *** propagation depends on the voltage crest *** at the grounded rod electrode,the channel transition phase *** the discharge moves back to the positive rod electrode due to recombination and *** the discharge constricts to the positive rod electrode,which forms a ***,at the grounded rod electrode,a channel is also *** each period,the channel will build up *** channel leads to the main discharge of the oscillating lightning impulse voltage.

关键词： oscillating electrode lightning

The hyperpycnite problem

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Journal of Palaeogeography 2018年第3期7卷 197-238页

作者： g.Shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

Sedimentologic, oceanographic, and hydraulic engineering publications on hyperpycnal flows claim that （1） river flows transform into turbidity currents at plunge points near the shoreline, （2） hyperpycnal flows have the power to erode the seafloor and cause submarine canyons, and, （3） hyperpycnal flows are efficient in transporting sand across the shelf and can deliver sediments into the deep sea for developing submarine fans. Importantly, these claims do have economic implications for the petroleum industry for predicting sandy reservoirs in deep-water petroleum exploration. However, these claims are based strictly on experimental or theoretical basis, without the supporting empirical data from modern depositional systems. Therefore, the primary purpose of this article is to rigorously evaluate the merits of these claims. A global evaluation of density plumes, based on 26 case studies （e.g., Yellow River, Yangtze River, Copper River, Hugli River （ganges）, guadalquivir River, Rio de ]a Plata Estuary, Zambezi River, among others）, suggests a complex variability in nature. Real-world examples show that density plumes （1） occur in six different environments （i.e., marine, lacustrine, estuarine, lagoon, bay, and reef）; （2） are composed of six different compositional materials （e.g., siliciclastic, calciclastic, planktonic, etc.）; （3） derive material from 11 different sources （e.g., river flood, tidal estuary, subglacial, etc.）; （4） are subjected to 15 different external controls （e.g., tidal shear fronts, ocean currents, cyclones, tsunamis, etc.）; and, （5） exhibit 24 configurations （e.g., lobate, coalescing, linear, swirly, U-Turn, anastomosing, etc.）. Major problem areas are：（1） There are at least 16 types of hyperpycnal flows （e.g., density flow, underflow, high-density hyperpycnal plume, high-turbid mass flow, tide-modulated hyperpycnal flow, cyclone-induced hyperpycnal turbidity current, multi-layer hyperpycnal flows, etc.）, without an underpinning principle of flu

关键词： Density plumes Facies model Hyperpycnites Submarine fans Tidal shear fronts Ocean currents Turbiditycurrents Yellow River Yangtze River

Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations