检索结果-南通市图书馆

On the Effects of Driven Element L/D Ra.io a.d Length in VHF-SHF Ya.i-Uda.a.ra.s

Wireless Engineering a.d Technology 2023年第1期14卷 1-25页

作者： richard a. formato Consulting Engineer & Registered Pa.ent a.torney of Counsel Emeritus Cataldo & Fisher LLC Harwich MA USA

While the Ya.i-Uda.a.ra. ha. been studied for deca.es, one issue a.pea.s to ha.e received less a.tention tha. perha.s it should, na.ely, the effects on performa.ce of the a.ra.’s driven element length a.d its length-to-dia.eter ra.io. This pa.er looks a. tha. question. It shows tha. decrea.ing the L/D ra.io increa.es impeda.ce ba.dwidth, but it ma. shift the IBW ba.d sufficiently fa. from the design frequency tha. other pa.a.eters such a. ga.n a.d front-to-ba.k ra.io proba.ly a.e a.versely a.fected. It a.so shows tha. a.ra. performa.ce is not rela.ively independent of element dia.eters. This pa.er a.so investiga.es the effect of lengthening the driven element, which ca. substa.tia.ly improve IBW. Severa. itera.ions of a.3-element prototype a.d improved a.ra.s a.e modeled with the Method of Moments a.d discussed in deta.l. a.five step design procedure is recommended a.d a.plied to a.Genetic a.gorithm-optimized 3-element Ya.i a. 146 MHz. This a.ra. exhibits excellent performa.ce in terms of ga.n, front-to-ba.k ra.io, a.d especia.ly impeda.ce ba.dwidth (nea.ly 14% for volta.e sta.ding wa.e ra.io ≤ 2:1 with two frequencies a. which 50 ? is a.most perfectly ma.ched). While the a.a.ysis a.d recommended design steps a.e a.plied to cylindrica. a.ra. elements, which commonly a.e a.uminum tubing for sta.d-a.one VHF-SHF Ya.is, they ca. be a.plied to other element geometries a. well using equiva.ent cylindrica. ra.ii, for exa.ple, Printed Circuit Boa.d tra.es for pla.a. a.ra.s. One consequence of lengthening the driven element while reducing its L/D ra.io is tha. some rea.ta.ce is introduced a. the a.ra. feedpoint which must be tuned out, a.d two a.proa.hes for doing so a.e suggested.

关键词： Ya.i a.ra. Driven Element Impeda.ce Ba.dwidth

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

Six-Element Ya.i a.ra. Designs Using Centra. Force Optimiza.ion with Pseudo Ra.dom Nega.ive Gra.ity

引用

Wireless Engineering a.d Technology 2021年第3期12卷 23-51页

作者： richard a. formato Ca.a.do & Fisher LLC Woburn USA

a.six-element Ya.i-Uda.a.ra. is optima.ly designed using Centra. Force Optimiza.ion (CFO) with a.sma.l a.ount of pseudo ra.domly injected nega.ive gra.ity. CFO is a.simple, deterministic meta.euristic a.a.ogizing gra.ita.iona. kinema.ics (motion of ma.ses under the influence of gra.ity). It ha. been very effective in a.dressing a.wide ra.ge of a.tenna.a.d other problems a.d norma.ly employs only positive gra.ity. With positive gra.ity the six element CFO-designed Ya.i a.ra. described here exhibits excellent performa.ce with respect to the objectives of impeda.ce ba.dwidth a.d forwa.d ga.n. This pa.er a.dresses the question of wha. ha.pens when a.sma.l a.ount of nega.ive gra.ity is injected into the CFO a.gorithm. Does doing so ha.e a.y effect, beneficia., nega.ive or neutra.? In this pa.ticula. ca.e nega.ive gra.ity improves CFO’s explora.ion a.d crea.es a.region of optima.ity conta.ning ma.y designs tha. perform a.out a. well a. or better tha. the a.ra. discovered with only positive gra.ity. Without some nega.ive gra.ity these a.ra. configura.ions a.e overlooked. This Ya.i-Uda.a.ra. design exa.ple suggests tha. a.tenna. optimized or designed using deterministic CFO ma. well benefit by including a.sma.l a.ount of nega.ive gra.ity, a.d tha. the nega.ive gra.ity a.proa.h merits further study.

关键词： a.tenna 6-Element a.ra. Ya.i Ya.i-Uda a.ra. Impeda.ce Ba.dwidth VSWR Forwa.d Ga.n a.tenna.Design a.tenna.Optimiza.ion Centra. Force Optimiza.ion CFO Deterministic Meta.euristic Evolutiona.y a.gorithm Gra.ity Gra.ita.iona. Kinema.ics Explora.ion Exploita.ion

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

Centra. Force Optimiza.ion with Gra.ity <0, Elitism, a.d Dyna.ic Threshold Optimiza.ion: a. a.tenna.a.plica.ion, 6-Element Ya.i-Uda.a.ra.s

引用

Wireless Engineering a.d Technology 2021年第4期12卷 53-82页

作者： richard a. formato Consulting Engineer & Registered Pa.ent a.torney of Counsel Emeritus Cataldo & Fisher LLC Woburn MA USA

This pa.er investiga.es the effect of a.ding three extensions to Centra. Force Optimiza.ion when it is used a. the Globa. Sea.ch a.d Optimiza.ion method for the design a.d optimiza.ion of 6-elementYa.i-Uda.a.ra.s. Those extena.>sions are Negative Gravity, Elitism, and Dynamic Threshold Optimization. Ta.>he basic CFO heuristic does not include any of these, but adding them substantially improves the algorithm’s performance. This paper extends the work reported in a previous paper that considered only negative gravity and which showed a significant performance improvement over a range of optimized arrays. Still better results are obtained by adding to the mix Elitism and DTO. An overall improvement in best fitness of 19.16% is achieved by doing so. While the work reported here was limited to the design/optimization of 6-a.>a.> a.>a.>a.>a.>a. style="font-fa.ily:"">a. style="font-fa.ily:Verda.a.">element Ya.is, the rea.ona.le inference ba.ed on these da.a.is tha. a.y a.tenna.design/optimiza.ion problem, indeed a.y Globa. Sea.ch a.d Optimiza./spa

关键词： Ya.i Ya.i-Uda a.ra. a.tenna a.tenna.Design Optimiza.ion Centra. Force Centra. Force Optimiza.ion CFO CFO-GED Nega.ive Gra.ity Elitism Dyna.ic Threshold Optimiza.ion DTO Dyna.ic Threshold Meta.euristic Evolutiona.y Computa.ion

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

Improving Ba.dwidth of Ya.i-Uda.a.ra.s

引用

Wireless Engineering a.d Technology 2012年第1期3卷 18-24页

作者： richard a. formato 不详

a.novel a.proa.h for improving a.tenna.ba.dwidth is described using a.6-element Ya.i-Uda.a.ra. a. a. exa.ple. The new a.proa.h a.plies Centra. Force Optimiza.ion, a.deterministic meta.euristic, a.d Va.ia.le Z0 technology, a.novel, proprieta.y design a.d optimiza.ion methodology, to produce a. a.ra. with 33.09% fra.tiona. impeda.ce ba.dwidth. This a.ra.’s performa.ce is compa.ed to its CFO-optimized Fixed Z0counterpa.t, a.d to the performa.ce of a.6-ele- ment Domina.ing Cone Line Sea.ch-optimized a.ra.. Both CFO-optimized a.tenna. exhibit better performa.ce tha. the DCLS a.ra., especia.ly with respect to impeda.ce ba.dwidth. a.though the Ya.i-Uda.a.tenna.wa. chosen to illustra.e this new a.proa.h to a.tenna.design a.d optimiza.ion, the methodology is entirely genera. a.d ca. be a.plied to a.y a.tenna.a.a.nst a.y set of performa.ce objectives.

关键词： Va.ia.le Z0 Z0 Cha.a.teristic Impeda.ce Feed System a.tenna a.tenna Design a.tenna Optimiza.ion Design Objectives Performa.ce Objectives Ba.dwidth Impeda.ce Ba.dwidth Broa.ba.d Ultra Wideba.d UWB Ya.i Ya.i-Uda Centra. Force Optimiza.ion CFO Numerica. Optimiza.ion Optimiza.ion a.gorithm Meta.euristic Domina.ing Cone Line Sea.ch DCLS

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

Endoscopic ma.a.ement of intra.a.tric penetra.ed a.justa.le ga.tric ba.d for morbid obesity

引用

World Journa. of Ga.troenterology 2006年第25期12卷 4098-4100页

作者： Giova.ni D De Pa.ma.a.tonio formato Vincenzo Pilone Ma.ia.Rega.Ma.ia.Elena.Giulia.o Imma.ola.a.Simeoli Pietro Forestieri Centro per l'Innova.ione Tecnologica.in Chirurgia.(ITC)-Dipa.timento di Chirurgia.Genera.e Oncologica.e Tecnologie a.a.za.e.Università degli Studi di Na.oli Federico Ⅱ Fa.oltà di Medicina.e Chirurgia NapoliItaly

这份报告与疾病的肥胖在一个病人描述胃内的渗透的可调节的胃的乐队的成功的内视镜的管理的一个案例。这里描述的案例的有利功课证明在移植的过程的可调节的胃的乐队不必在无征状的病人通过手术被移开。

关键词：内窥镜检查胃疾病肥胖病理机制

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.prelimina.y simula.ion study of influence of ba.kspla.h on the pla.tic scintilla.or detector design in HERD experiment

引用

Ra.ia.ion Detection Technology a.d Methods 2021年第3期5卷 332-338页

作者： Peng Hu Zhi-ga.g Wa.g Fa.io Ga.ga.o Fra.cesca.a.ema.no Corra.o a.toma.e Tia.-wei Ba. Yong-wei Dong Va.erio formato Dimitrios Kyra.zis Nicola.Mori Lorenzo Pa.ini Zheng Qua. Da.ide Serini Jun-jing Wa.g Rui-jie Wa.g Ming Xu Bo-bing Wu Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese a.a.emy of Sciences Beijing 100049China Istituto Na.iona.e di Fisica.Nuclea.e(INFN) Sezione di Bari70126 BariItaly Gra. Sa.so Science Institute(GSSI) 67100 L’AquilaItaly Istituto Na.iona.e di Fisica.Nuclea.e(INFN) Laboratori Nazionali del Gran Sasso67100 L’AquilaItaly Dipa.timento Intera.eneo di Fisica.dell’Universitàe del Politecnico di Ba.i 70125 BariItaly Istituto Na.iona.e di Fisica.Nuclea.e(INFN) Sezione di Roma Tor Vergata00133 RomeItaly Istituto Na.iona.e di Fisica.Nuclea.e(INFN) Sezione di Firenze50019 Sesto FiorentinoItaly

Ba.kground The pla.tic scintilla.or detector(PSD)is one of the detectors in the high energy cosmic ra.ia.ion detection(HERD)fa.ility,which is designed for ga.ma.ra. detection a.d a.redunda.t cha.ge *** will lea. to a.decrea.e in PSD’s performa.ce of ga.ma.ra. detection a.d cha.ge mea.urement,which should be ca.efully *** Two prelimina.y segmenta.ion schemes of the PSD a.d two veto stra.egies ha.e been proposed to suppress the ba.kspla.h *** this pa.er,we focus on the influence of the ba.kspla.h ca.sed by ga.ma.*** ga.ma.ra. trigger efficiency a.d identifica.ion efficiency were studied in the ca.e of different cell sizes a.d veto stra.egies,which ca. provide guida.ce on the PSD *** a.Monte Ca.lo simula.ion ba.ed on Gea.t4 ha. been *** simplify the simula.ion,the PSD is segmented into 1 cm3 cubes which ca. be ea.ily a.grega.ed into cells with different sizes during *** a.d conclusion Side_Veto ca. be used a. a.ba.eline design of veto stra.egy,wherea. Sma.t_Veto ca. be selected a. a. upgra.ed *** the PSD ba. cell with a.width of less tha. 11 cm a.d the PSD tile cell with a.width of less tha. 20 cm ca. a.hieve a.sufficiently high ga.ma.ra. trigger efficiency(>80%),which rea.izes the prima.y goa. of the ***,both the PSD ba. cell with a.width of less tha. 3 cm a.d the PSD tile cell with a.width of less tha. 20 cm ca. ensure a.sufficiently high ga.ma.ra. identifica.ion efficiency(>80%)for photons up to 800 GeV.

关键词： Pla.tic scintilla.or detector Ga.ma.ra. detection Ba.kspla.h Veto

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

Study of Sa.dy Soil Compa.tion

引用

Journa. of a.ricultura. Science a.d Technology(a. 2013年第5期3卷 356-367页

作者： a.drea.formato Gia. Pio Pucillo a.tonio a.a.na.e Depa.tment of a.ricultura. Science University of Naples Naples Italy

In this pa.er, a.study of sa.dy soil compa.tion with different gra.ulometry a.d moisture content ha. been performed, a.d soil mecha.ica. property va.ia.ions in moisture a.d gra.ulometry ha.e been investiga.ed. Investiga.ions were performed to compa.e hydrosta.ic compression test (HCT) responses a.d eva.ua.e the compression index, Cc, which is a. indica.or of the soil"s susceptibility to compa.tion-induced da.a.e. The experiments ha.e been performed on 24 soil sa.ples typologies. Ea.h sa.ple ha. been obta.ned by combining three types of soil gra.ulometry (types a. B a.d C) with a.rela.ive content va.ying from 0% to 100% in 20% increments. Soil type a.ha. a.gra.ulometry ra.ging between 0.5 mm a.d 1 mm, type B between 0.25 mm a.d 0.5 mm, a.d type C less tha. 0.25 mm. These sa.ples were representa.ive of a.sa.dy soil, chemica.ly ina.tive a.d ha. va.ious gra.ulometries a.d initia. moisture contents. a.cell for HCT ha. been set up to a.low the initia. volume mea.urement of the test pieces a.d the subsequent cha.ges during HCT with a. estima.ed error less tha. 0.1 cm3. a.l sa.ples were pre-compa.ted a.d prepa.ed in a.reement with the a.tua. sta.da.ds. The experimenta. da.a.a.e reported in dia.ra.s, the da.a.a.lowed compa.ison of the mecha.ica. beha.iors between the considered unsa.ura.ed soils a.d underlined how soil moisture a.d gra.ulometry a.fect soil response during HCT. Furthermore, beca.se of the methodology used, the equipment wa. very economica..

关键词：土壤压实红细胞压积粒度测定砂土水分含量压缩试验实验数据 HCT

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

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

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

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：