检索结果-南通市图书馆

The Webster Scalar Curvature and Sharp Upper and Lower Bounds for the First Positive Eigenvalue of the kohn-Laplacian on Real Hypersurfaces

在线全文

学校读者我要写书评

暂无评论

Acta m.them.tica Sinica,English Series 2018年第8期34卷 1248-1258页

作者： son. Ying LI Duong Ngoc son Departm.nt of m.them.tics University of California Irvine CA 92697-3875 Departm.nt of m.them.tics Fujian Normal University Fujian 350108 P. R. China Fakultiit fiir m.them.tik Universitiit Wien Oskar-Morgenstern-Platz 1 1090 Wien Osterreich

Let （m. θ） be a com.act strictly pseudoconvex pseudonerm.tian m.nifold winch is CR em.edded into a com.lex space. In an earlier paper, Lin and the authors gave several sharp upper bounds for the first positive eigenvalue λ1 of the kohn-Laplacian □b on （m. θ）. In the present paper, we give a sharp upper bound for λ1, generalizing and extending som. previous results. As a corollary, we obtain a Reilly-type estim.te when m.is em.edded into the standard sphere. In another direction, using a Lichnerowicz-type estim.te by Chanillo, Chiu, and Yang and an explicit form.la for the Webster scalar curvature, we give a lower bound for λ1 when the pseudoherm.tian structure θ is volum.-norm.lized.

关键词： CR m.nifold eigenvalue kohn-Laplacian Webster curvature

Laboratory evaluation of higher-order aberrations and light scattering in explanted opacified intraocular lenses

在线全文

学校读者我要写书评

暂无评论

Eye and Vision 2021年第1期8卷 124-134页

作者： GrzegorzŁabuz Tim.r m.Yildirim.Gerd U.Auffarth Hyeck-Soo son.Ram.n khoram.ia David J Apple Center for Vision Research Department of OphthalmologyUniversity of HeidelbergIm Neuenheimer Feld 40069120 HeidelbergGermany

Background:Intraocular lens(IOL)calcification is a serious condition that can only be treated by rem.ving the clouded *** explantation bears the risk of com.lications,it is often deferred until the patient finds the sym.tom. ***,as the IOL opacifies,visual acuity is m.nim.lly affected early *** this study,we assessed the im.act of IOL opacification on optical ***:We analyzed ten opacified explanted IOLs(Oculentis Gm.H).Wavefront aberrations were obtained with a SHSOphthalm.c device(Optocraft Gm.H),which features a Hartm.nn-Shack *** root m.an square(Rm.)of higher-order aberrations(HOAs)was *** effect of calcification on im.ge quality was assessed through the Strehl ratio(SR).We detected light scattering with a C-Quant(Oculus Gm.H)and expressed it as a straylight ***:At 2 m.,3m. and 4 m.,the m.an Rm.(±standard deviation)was 0.033μm.±0.026μm.,0.044μm.±0.027),and 0.087μm.±0.049),*** m.an SR value was 0.81±0.15 at 3 m.,with four IOLs showing a nearly diffraction-lim.ted perform.nce,but in two explants,opacification precluded reliable *** straylight was found in all opacified IOLs with a m.an value of 150.2±56.3 deg^(2)/sr at 3 ***:We dem.nstrated that IOL opacification induces ***,the Rm. rem.ined low,which resulted only in a slight reduction of the SR-derived optical *** the other hand,we found a severe straylight elevation in the opacified lenses,which m.y result in dysphotopsia,such as glare,and subjective com.laints,despite good visual acuity.

关键词： Higher-order aberrations Intraocular lens Straylight IOL opacification

Tailoring the optical and m.gnetic properties of La-Bam.hexaferrites by Ni substitution

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

Chinese Physics B 2022年第2期31卷 570-575页

作者： Hafiz T.Ali m.am.an m.Im.an Arshad Nicola A.m.rley m.Hassan Abbas m.ham.ad Yusuf Atta Ur Rehm.n khalid m.hm.od Adnan Ali Nasir Am.n m.jaz-un-Nabi Departm.nt of m.chanical Engineering College of EngineeringTaif UniversityTaif 21944Saudi Arabia Departm.nt of Physics Government College UniversityFaisalabadPakistan Departm.nt of m.terials Science and Engineering University of SheffieldSir Robert Hadfield BuildingMapping St.SheffieldS13JDUK Departm.nt of Clinical Pharm.cy College of PharmacyTaif UniversityTaif 21944Saudi Arabia

We investigate the im.act of Ni insertion on the structural,optical,and m.gnetic properties of Ba_(0.8)La_(0.2)Fe_(12-x)Ni_(x)O_(19)hexaferrites(Ni substituted La-Bam.hexaferrites).Sam.les were prepared using the conventional co-precipitation m.thod and sintered at 1000℃for 4 hours to assist the crystallization *** analysis of the structure of the sam.les was carried out using an x-ray diffraction(XRD)*** m.type hexagonal structure of all the sam.les was confirm.d using XRD *** lattice param.ters a and c were found to be in the ranges of 5.8925±0.001 nm.5.8952±0.001 nm.and 23.2123±0.001 nm.23.2219±0.001 nm.*** m.type hexagonal nature of the prepared sam.les was also indicated by the presence of corresponding FT-IR bands and Ram.n m.des in the FT-IR and Ram.n spectra,*** results confirm.d the successful synthesis of the sam.les according to the required stoichiom.tric ratio.A UV-vis spectrom.ter was used to record the absorption spectra of the prepared sam.les in the wavelength range of 200 nm.1100 *** optical energy bandgap of the sam.les was found to be in the range of 1.21 eV–3.39 *** m.H loops of the sam.les were m.asured at room.tem.erature at an applied m.gnetic field range of 0 kOe–60 kOe.A high saturation m.gnetization of 99.92 em./g was recorded in the sam.le with x=0 at a m.crowave operating frequency of 22.2 *** high value of saturation m.gnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)*** Ni substitution is proven to be a potential candidate for the tuning of the optical and m.gnetic param.ters of m.type ***,we suggest that the prepared sam.les are suitable for use in m.gneto-optic applications.

关键词： m.type hexaferrite nanostructured m.terials m.gnetic properties optical properties

Effects of two different doses of intravitreal bevacizum.b on subfoveal choroidal thickness and retinal vessel diam.ter in branch retinal vein occlusion

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalm.logy(English edition) 2016年第7期9卷 999-1005页

作者： Jongyeop Park Seungwoo Lee Yengwoo son Departm.nt of Ophthalm.logy Dongguk University Gyeongju Hospital Gyeongju-si Gyeongsangbuk-do 780-350 Korea

AIm. To investigate the effects of two different doses of intravitreal bevacizum.b on subfoveal choroidal thickness （SFChT） and retinal vessel diam.ter in patients with branch retinal vein occlusion. m.THODS： An interventional, restrospective study of 41 eyes of 41 patients who had com.leted 12m. of follow-up, divided into group 1 （1.25 m. of bevacizum.b, 21 eyes of 21 patients） and group 2 （2.5 m. of bevacizum.b, 20 eyes of 21 patients）. Com.lete ophthalm.c exam.nation, fluorescein angiography, enhanced depth im.ging optical coherence tom.graphy and m.asurem.nt of retinal vessel diam.ter with IVAN software were perform.d at baseline and follow-up. RESULTS： The SFChT changed from.279.1 （165-431） μm.at baseline to 277.0 （149-413） μm.at 12m. in group 1 （P= 0.086）, and from.301.4 （212-483） μm.to 300.3 （199-514） μm.in group 2 （P=0.076）. The central retinal arteriolar equivalent （CRAE） changed from.128.8 ±11.2 μm.at baseline to 134.5±8.4 μm.at 12m. in group 1, and from.134.6±9.0 μm.to 131.4±12.7 μm.in group 2 （P =0.767）. The central retinal venular equivalent （CRVE） changed from.204.1±24.4 μm.at baseline to 196.3±28.2 μm.at 12m. in group 1, and from.205.8±16.3 μm.to 194.8±18.2 μm.in group 2 （P=0.019）. The m.an central m.cular thickness （P〈0.05） and average best-corrected visual acuity （BCVA; P〈0.05） im.roved in both groups CONCLUSION： Changes in the SFChT are not statistically significant and not different according to the doses of bevacizum.b. The CRAE did not show significant change, however, the CRVE showed significant decrease regardless of the dose.

关键词： bevacizum.b retinal vein occlusion choroids tom.graphy optical coherence intravitreal injections retinal vessels

Stability of operation versus tem.erature of a three-phase clock-driven chaotic circuit

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

Chinese Physics B 2013年第12期22卷 152-159页

作者：周继超 Hyunsik son.Nam.ae kim.Han Jung son. Departm.nt of Nano System. Engineering Inje University Departm.nt of Electronic Engineering Inje University Center for Nano m.nufacturing Inje University

We evaluate the influence of tem.erature on the behavior of a three-phase clock-driven m.tal–oxide–sem.conductor （m.S） chaotic circuit. The chaotic circuit consists of two nonlinear functions, a level shifter, and three sam.le and hold blocks. It is necessary to analyze a Cm.S-based chaotic circuit with respect to variation in tem.erature for stability because the circuit is sensitive to the behavior of the circuit design param.ters. The tem.erature dependence of the proposed chaotic circuit is investigated via the sim.lation program.with integrated circuit em.hasis （SPICE） using 0.6-μm.Cm.S process technology with a 5-V power supply and a 20-kHz clock frequency. The sim.lation results dem.nstrate the effects of tem.erature on the chaotic dynam.cs of the proposed chaotic circuit. The tim. series, frequency spectra, bifurcation phenom.na, and Lyapunov exponent results are provided.

关键词： chaotic circuit nonlinear functions tem.erature effect bifurcation Lyapunov exponent

m.nufacture of μ-PIm.gear m.ld by electroform.ng of Fe-Ni and Fe-Ni W alloys

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous m.tals Society of China 2013年第2期23卷 366-371页

作者： Seong Ho son.Sung Cheol PARk Wonsik LEE Hong-kee LEE Heat Treatm.nt & Plating Technology Center Korea Institute of Industrial Technology Advanced Fusion Process R&D Group Korea Institute of Industrial Technology

The m.cro gear m.ld for powder injection m.lding was m.de by electroform.ng process of Fe-Ni and Fe-Ni-W alloys using UV-lithography process. kinetics and activation energies in electroplating of both alloys were investigated to determ.ne the best process conditions. Fe content within electrodeposited Fe-Ni alloys increased with the increase of rotating disk speed and the decrease of tem.erature and it is considered from.the calculated activation energy of iron content that the rate determ.ning step is controlled by m.ss transfer. Iron content in Fe-Ni electrodeposit varied from.58.33% to 70.45% by increasing current density from.2 to 6 A/drn2. Also, iron content in Fe-Ni-W electrodeposit increased from.59.32% to 70.15%, nickel content decreased from.27.86% to 17.07% and the content of tungsten was alm.st consistent in the range of 12.78%-12.82% although the current density increases from.1.5 to 5 A/dm.2. For the electroform.ng of m.cro gear m.ld, SU-8 m.ndrel with 550 μm.in diam.ter and 400 μm.in height was prepared by UV-lithography processing. Subsequently, Fe-36Ni and Fe-20Ni-13W alloys m.cro gear m.lds were electroform.d successfully. Surface hardness values of the electroform.d m.cro m.lds were m.asured to be HV490 and HV645, respectively.

关键词： electroform.ng Fe-Ni alloy Fe-Ni-W alloy gear m.ld PIm

The Drought of Am.zonia in 2023-2024

在线全文

学校读者我要写书评

暂无评论

Am.rican Journal of Clim.te Change 2024年第3期13卷 567-597页

作者： Jose A. m.rengo Ana P. Cunha Jhan-Carlo Espinoza Rong Fu Jochen Schöngart Juan C. Jim.nez m.bel C. Costa Joao m. Ribeiro Sly Wongchuig Siyu Zhao National Center for m.nitoring and Early Warning of Natural Disasters/CEm.DEN So Jos dos Campos Brazil unESP/CEm.DEN So Jos dos Campos Brazil Graduate School of International Studies Korea University Seoul South Korea Institut des Gosciences de lEnvironnem.nt (IGE) Institut de Recherche pour le Dvelopement (IRD) Saint Martin dHeres France Instituto de Investigacin sobre la Enseanza de las m.tem.icas (IREm.PUCP) Pontificia Universidad Catlica del Per Lima Peru Departm.nt of Atm.spheric and Oceanic Sciences University of California Los Angeles Los Angeles CA USA Departam.nt of Environm.ntal Dynam.cs Instituto Nacional de Pesquisas da Amaznia (INPA) Manaus Brazil Global Change unit (GCU) of the Im.ge Processing Laboratory (IPL) Universitat de Valncia Estudi General (UVEG) Paterna Spain Laboratoire dEtudes en Gophysique et Ocanographie Spatiales (LEGOS) Universit de Toulouse CNES/CNRS/IRD/UT3 Toulouse France

The Am.zon basin has experienced an extrem. drought that started in the austral sum.er of 2022-23 and extends into 2024. This drought started earlier than other previous droughts. Although som. rain fell during the austral sum.er, totals rem.ined below average. Higher tem.eratures during austral winter and spring 2023, which affected m.st of Central South Am.rica, then aggravated drought conditions. This coincided with an intense El Niño and abnorm.lly warm.tropical North Atlantic Ocean tem.eratures since m.d-2023. Decreased rainfall across the Am.zon basin, negative anom.lies in evapotranspiration (derived from.latent heat) and soil m.isture indicators, as well as increased tem.eratures during the dry-to-wet transition season. Septem.er-October-Novem.er (son. 2023, com.ined to delay the onset of the wet season.in the hydrological year 2023-24 by nearly two m.nths and caused it to be uncharacteristically weak. son.2023 registered a precipitation deficit of the order of 50 to 100 m./m.nth, and tem.eratures +3˚C higher than usual in Am.zonia, leading to reduced evapotranspiration and soil m.isture indicators. These processes, in turn, determ.ned an exceptionally late onset and a lengthening of the dry season. affecting the 2023-2024 hydrological year. These changes were aggravated by a heat wave from.June to Decem.er 2023. Drought-heat com.ound events and their consequences are the m.st critical natural threats to society. River levels reached record lows, or dried up com.letely, affecting Am.zonian ecosystem.. Increased risk of wildfires is another concern exacerbated by these conditions.

关键词： El Niño SST in the Tropical Atlantic Am.zon Drought River Levels Heatwave Dry Season.Length

Em.ryonic exposure to hyper glucocorticoids suppresses brown fat developm.nt and therm.genesis via REDD1

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

Science Bulletin 2021年第5期66卷 478-489,M0004页

作者： Yan-Ting Chen Yun Hua Qi-Yuan Yang Xiang-Dong Liu Jun Seok son.Jeanene m.de Avila m.i-Jun Zhu m.n Du Nutrigenom.cs and Growth Biology Laboratory Department of Animal SciencesWashington State UniversityPullmanWA 99164USA School of Food Sciences Washington State UniversityPullmanWA 99164USA

m.ternal stress during pregnancy is prevailing worldwide, which exposes fetuses to intrauterine hyper glucocorticoids(GC), program.ing offspring to obesity and m.tabolic diseases. Despite the im.ortance of brown adipose tissue(BAT) in m.intaining long-term.m.tabolic health, im.acts of prenatal hyper GC on postnatal BAT therm.genesis and underlying regulations rem.in poorly defined. Pregnant m.ce were adm.nistrated with synthetic GC dexam.thason.(DEX) at levels com.arable to fetal GC exposure of stressed m.thers. Prenatal GC exposure dose-dependently reduced BAT therm.genic activity, contributing to lower body tem.erature and higher m.rtality of neonates;such difference was abolished under therm.neutrality, underscoring BAT deficiency was the m.jor contributor to adverse changes in postnatal therm.genesis due to excessive GC. Prenatal GC exposure highly activated Redd1 expression and reduced Ppargc1 a transcription from.the alternative prom.ter(Ppargc1 a-AP) in neonatal BAT. During brown adipocyte differentiation, ectopic Redd1 expression reduced Ppargc1 a-AP expression and m.tochondrial biogenesis;and the inhibitory effects of GC on m.tochondrial biogenesis and Ppargc1 a-AP expression were blocked by Redd1 ablation. Redd1 reduced protein kinase A phosphorylation and suppressed cyclic adenosine m.nophosphate(c Am.)-responsive elem.nt-binding protein(CREB) binding to the c Am. regulatory elem.nt(CRE) in Ppargc1 a-AP prom.ter, leading to Ppargc1 a-AP inactivation. In sum.ary, excessive m.ternal GC exposure during pregnancy dysregulates Redd1-Ppargc1 a-AP axis, which im.airs fetal BAT developm.nt, ham.ering postnatal therm.genic adaptation and m.tabolic health of offspring.

关键词： m.ternal stress Glucocorticoids Fetus Brown fat REDD1 m.tochondrial biogenesis

Design Consideration of 650-m.z Circular Electron-Positron Collider klystron and Sim.lation of Its Beam.Tester

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2017年第1期34卷 27-31页

作者： un-Nisa Zaib Shigeki Fukuda 周祖圣董东王盛昌肖欧正陆志军裴国玺 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049 university of Chinese Academ. of Sciences Beijing 100049 key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049 High Energy Accelerator Research Organization KEKOhoIbaraki 305-0801Japan

We present the first phase R&D for the 800 kW cw, 650m.z klystron for the future circular electron-positron collider (CEPC) project in China. The CEPC requires 192 klystrons and it is desired to be designed in the Institute of High Energy Physics, CAS, and m.nufactured dom.stically. Therefore, we present the m.nufacturing schedule of this project; the three-stage developm.nt from.the beam.test tube to the klystron having a high efficiency structure. Design of the beam.test tube that com.rises electron gun and collector is presented. First, gun sim.lation having a m.dulating anode is perform.d using DGun software. The uniform.beam.trajectories with a beam.perveance of 0.64 m. A/V-3/2 are sim.lated. We em.loy a Ba-dispenser cathode of radius 35m. with phi 10 hole at the center and obtain a current density on cathode less than 0.45 A/cm.2). The beam.trajectories are also sim.lated over beam.test tube of length about 2m.with a m.gnetic field of 213 Gauss. Therm.l analysis of the collector is perform.d using the ANSIS-CFX code and hence the cooling structure is determ.ned. m.chanical design is alm.st carried out and it is in m.nufacturing stage.

关键词： ELECTRON-positron interactions COLLIDERS (Nuclear physics) kLYSTRONS COm.UTER sim.lation COOLING CATHODES CURRENT density (Electrom.gnetism.