期刊文献+
共找到106篇文章
< 1 2 6 >
每页显示 20 50 100
Simulation and experimental study on the use of shaped charge jet as transient antennas for radiating electromagnetic pulses
1
作者 Jiahui Guo Bin Ma +2 位作者 Zhengxiang Huang Yong Peng Xin Jia 《Defence Technology(防务技术)》 2025年第5期260-274,共15页
In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a tran... In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a transient antenna was proposed.During the research,crucial characteristics of the transient antenna formed by a shaped charge with a 30 mm diameter,such as resonant frequency,radiation pattern,and radiation efficiency,were evaluated.The typical shaped charge jet morphology was obtained based on the simulations,in which it could insight the dynamic behavior of the shaped charge jet selected.An equivalent model experiment was employed to test the radiation efficiency,and it showed that a shorting pin loading method could increase the relative bandwidth of the jet antenna to 32.8%,and the experimental results correlate with the theoretical predictions for half-wave dipole antennas reasonably well.Additionally,variations in the diameter of the shaped charge jet were found to affect the input impedance and impedance bandwidth,while the length of the jet influenced the resonant frequency of the antenna.This suggests that altering these parameters can achieve reconfigurability of the jet antenna. 展开更多
关键词 Shaped charge Transient antenna Electromagnetic pulse Radiated power Reconfigurable antenna
在线阅读 下载PDF
The Equivalent Parameters of an Inclined Slot in Two Crossed Waveguides with Radiating Slots
2
作者 Lue Shanwei & Tang Hongzhen(Beijing University of Aeronautics and Astronautics, Beijing 100083, China) 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1995年第1期73-80,共8页
The effect of longitudinal-offset radiating slots on a centered-inclined feeding slot in the common broad wall of the two crossed rectangular waveguides is analysed quantitatively. The corresponding equivalent paramet... The effect of longitudinal-offset radiating slots on a centered-inclined feeding slot in the common broad wall of the two crossed rectangular waveguides is analysed quantitatively. The corresponding equivalent parameters are computed by employing the moment method. The numerical results of resonant length of the feeding slot, VSWR and coupling parameter are showed and compared with the case of no radiating slots and short-end. The agreement between theory and experiment is good. 展开更多
关键词 radiating slot Feeding slot Crossed waveguide Equivalent parameters
在线阅读 下载PDF
Health Phys.Abstracts,Volume 128,Number 2
3
《辐射防护》 北大核心 2025年第3期305-309,共5页
Estimate of the Deterministic Neutron RBE for Radiation-induced Pseudo-Pelger Huët Cell Formation R.E.Goans1,2,C.J.Iddins1,R.E.Goans,Jr.3(1.Radiation Emergency Assistance Center/Training Site,Oak Ridge,TN;2.MJW C... Estimate of the Deterministic Neutron RBE for Radiation-induced Pseudo-Pelger Huët Cell Formation R.E.Goans1,2,C.J.Iddins1,R.E.Goans,Jr.3(1.Radiation Emergency Assistance Center/Training Site,Oak Ridge,TN;2.MJW Corporation,Amherst,NY;3.LMU Debusk School of Medicine,Harrogate,TN)Abstract:Using archival peripheral blood slides from radiation accident patients,we have recently described the pseudo-Pelger Huët anomaly(PPHA)in neutrophils as a new radiation-induced biomarker,useful for dosimetry not only immediately after a radiation incident but also potentially helpful as a tool in retrospective dosimetry. 展开更多
关键词 deterministic radiation induced pseudo pelger hu t cell neutron DOSIMETRY archival peripheral blood slides radiation accident biomarker
在线阅读 下载PDF
Health Phys. Abstracts,Volume 128,Number 4
4
《辐射防护》 北大核心 2025年第4期437-440,共4页
Protecting Our Own:A Method for Reducing Breast Radiation Exposure in Healthcare Workers Lauren Zammerilla Westcott1, Gerald O. Ogola2, Chet R. Rees3(1. Department of Surgery, Baylor University Medical Center, Dallas,... Protecting Our Own:A Method for Reducing Breast Radiation Exposure in Healthcare Workers Lauren Zammerilla Westcott1, Gerald O. Ogola2, Chet R. Rees3(1. Department of Surgery, Baylor University Medical Center, Dallas, TX;2. Department of Biostatistics, Baylor University Medical Center, Dallas, TX;3. Department of Interventional Radiology, Baylor University Medical Center, Dallas, TX). 展开更多
关键词 healthcare workers breast radiation exposure interventional radiology protection methods breast radiation
在线阅读 下载PDF
Selective synthesis of 7-ester indoles and bis-indoles
5
作者 WANG Yong-hui 《化学研究与应用》 北大核心 2025年第10期3201-3208,共8页
multi-component reaction was reported for the synthesis of 7-ester indoles and bis-indoles under microwave-assisted conditions,enriching and expanding the library of heterocyclic compounds.This reaction started from e... multi-component reaction was reported for the synthesis of 7-ester indoles and bis-indoles under microwave-assisted conditions,enriching and expanding the library of heterocyclic compounds.This reaction started from enamine ketone,aromatic ketone aldehyde hydrate,and carboxylic acid,and selectively synthesized 7-ester indoles and bis-indoles by changing the substituted enamine ketone substrate.This method had the characteristics of high regional selectivity,short reaction time,and green environmental protection. 展开更多
关键词 microwave radiation 7-ester indoles bis-indoles
在线阅读 下载PDF
Design and optimization of quadrupole and sextupole magnets for Shenzhen Innovation Light-source Facility storage ring
6
作者 Zhu Jiawu Zhang Miao Wang Yong 《强激光与粒子束》 北大核心 2025年第7期83-90,共8页
As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude redu... As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude reduction in beam emittance compared to the 3^(rd) generation storage ring.This significantly enhance the radiation brightness and coherence.The multipole magnets of many types for SILF storage ring are under preliminary design,which require high integral field homogeneity.As a result,a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D^(■)python script.The procedure considers also the 3D field effect which makes the optimization more straightforward.In this paper,the design of the quadrupole and sextupole magnets for SILF storage ring is first presented,followed by a detailed description of the implemented pole shape optimization method. 展开更多
关键词 synchrotron radiation facility quadrupole magnet sextupole magnet pole shape optimization
在线阅读 下载PDF
Detuning effect corrections using octupoles in diffraction-limited storage ring
7
作者 Xuan Shouzhi Tian Shunqiang +2 位作者 Liu Xinzhong Gong Yihao Mao Linglong 《强激光与粒子束》 北大核心 2025年第7期72-82,共11页
The next generation of synchrotron radiation light sources features extremely low emittance,enabling the generation of synchrotron radiation with significantly higher brilliance,which facilitates the exploration of ma... The next generation of synchrotron radiation light sources features extremely low emittance,enabling the generation of synchrotron radiation with significantly higher brilliance,which facilitates the exploration of matter at smaller scales.However,the extremely low emittance results in stronger sextupole magnet strengths,leading to high natural chromaticity.This necessitates the use of sextupole magnets to correct the natural chromaticity.For the Shanghai Synchrotron Radiation Facility Upgrade(SSRF-U),a lattice was designed for the storage ring that can achieve an ultra-low natural emittance of 72.2 pm·rad at the beam energy of 3.5 GeV.However,the significant detuning effects,driven by high second-order resonant driving terms due to strong sextupoles,will degrade the performance of the facility.To resolve this issue,installation of octupoles in the SSRF-U storage ring has been planned.This paper presents the study results on configuration selection and optimization method for the octupoles.An optimal solution for the SSRF-U storage ring was obtained to effectively mitigate the amplitude-dependent tune shift and the second-order chromaticity,consequently leading to an increased dynamic aperture(DA),momentum acceptance(MA),and reduced sensitivity to magnetic field errors. 展开更多
关键词 Shanghai Synchrotron Radiation Facility Upgrade OCTUPOLE amplitude-dependent tune shift dynamic aperture momentum aperture
在线阅读 下载PDF
Health Phys. Abstracts,Volume 128,Number 5
8
《辐射防护》 北大核心 2025年第4期440-444,共5页
Evaluation of a Commercially Available Radiochromic Film for Use as a Complementary Dosimeter for Rapid In-field Low Photon Equivalent Radiation Dose (≤50 mSv) Monitoring Nicky Nivi1, Helen Moise1,2, Ana Pejovic'... Evaluation of a Commercially Available Radiochromic Film for Use as a Complementary Dosimeter for Rapid In-field Low Photon Equivalent Radiation Dose (≤50 mSv) Monitoring Nicky Nivi1, Helen Moise1,2, Ana Pejovic'-Milic'1(1. Department of Physics, Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario, M5B 2K3;2. Autonomous and Radiological Technologies Section, Defense Research and Development Canada, PO Box 4000 Stn Main,Medicine Hat, Alberta, T1A 8K6). 展开更多
关键词 low photon equivalent radiation dose autonomous radiological technologies complementary dosimeter DOSIMETER field monitoring radiochromic film
在线阅读 下载PDF
Infrared-NeRF:a low resolution thermal infrared light field 3D reconstruction method based on NeRF
9
作者 HUANG Yi-Fan WANG Rui +2 位作者 DENG Li-Ming LI Jia-Jia LI Xi-Cai 《红外与毫米波学报》 北大核心 2025年第4期605-616,共12页
This article proposes a three-dimensional light field reconstruction method based on neural radiation field(NeRF)called Infrared NeRF for low resolution thermal infrared scenes.Based on the characteristics of the low ... This article proposes a three-dimensional light field reconstruction method based on neural radiation field(NeRF)called Infrared NeRF for low resolution thermal infrared scenes.Based on the characteristics of the low resolution thermal infrared imaging,various optimizations have been carried out to improve the speed and accuracy of thermal infrared 3D reconstruction.Firstly,inspired by Boltzmann's law of thermal radiation,distance is incorporated into the NeRF model for the first time,resulting in a nonlinear propagation of a single ray and a more accurate description of the physical property that infrared radiation intensity decreases with increasing distance.Secondly,in terms of improving inference speed,based on the phenomenon of high and low frequency distribution of foreground and background in infrared images,a multi ray non-uniform light synthesis strategy is proposed to make the model pay more attention to foreground objects in the scene,reduce the distribution of light in the background,and significantly reduce training time without reducing accuracy.In addition,compared to visible light scenes,infrared images only have a single channel,so fewer network parameters are required.Experiments using the same training data and data filtering method showed that,compared to the original NeRF,the improved network achieved an average improvement of 13.8%and 4.62%in PSNR and SSIM,respectively,while an average decreases of 46%in LPIPS.And thanks to the optimization of network layers and data filtering methods,training only takes about 25%of the original method's time to achieve convergence.Finally,for scenes with weak backgrounds,this article improves the inference speed of the model by 4-6 times compared to the original NeRF by limiting the query interval of the model. 展开更多
关键词 neural radiation field 3D reconstruction thermal infrared NeRF foreground segmentation low resolution
在线阅读 下载PDF
Bismuth's role in quaternary thulium doped tellurite glasses:Achieving optical clarity and radiation shielding
10
作者 N.A.M.Rusni N.A.Abdul-Manaf +3 位作者 N.Ahmad L.Hasnimulyati W.Y.W.Yusoff A.Azuraida 《Defence Technology(防务技术)》 2025年第9期134-144,共11页
This study explores the impact of bismuth oxide(Bi_(2)O_(3))on the optical and radiation shielding properties of transparent,lead-free thulium-doped bismuth borotellurite radiation shielding glass.The investigated gla... This study explores the impact of bismuth oxide(Bi_(2)O_(3))on the optical and radiation shielding properties of transparent,lead-free thulium-doped bismuth borotellurite radiation shielding glass.The investigated glass composition follows the formula[(TeO_(2))_(75)(B_(2)O_(3))_(25)]_(98-x)(Bi_(2)O_(3))_x[Tm_(2)O_(3)]_(2),where x=0 mol%,5 mol%,10 mol%,15 mol%,20 mol%,25 mol%,and 30 mol%.All glass samples remain transparent,with an optical bandgap(E_(opt))exceeding 3.1 e V,ensuring visible light transmission.Radiation shielding data from Phy-X and XCom reveal interactions of the photoelectric effect,Compton scattering,and pair production,with minimal relative difference in mass attenuation coefficient(MAC)which is between0.05 and 0.56.At 0.662 Me V photon energy,the 20 mol%and 25 mol%Bi_(2)O_(3)glasses exhibit significantly higher Phy-X MAC values than other samples,except RS 520 glass,which contains 71%Pb O.Despite incorporating only up to 25 mol%Bi_(2)O_(3),these glasses outperform others in density,half-value layer(HVL),and mean free path(MFP).Correlating E_(opt)and MAC,the 20 mol%Bi_(2)O_(3)glass is the best candidate for transparent radiation shielding glass due to its wide optical bandgap which prevents ionization of trapped holes.Significantly,the linkage between MFP and molar refraction was also discovered based on the particle size influence on both parameters. 展开更多
关键词 Thulium-doped bismuth borotellurite glasses OPTICAL Radiation shielding LEAD-FREE Phy-X XCom
在线阅读 下载PDF
一个NEK基因家族新成员的克隆和鉴定 被引量:3
11
作者 李梅章 褚嘉祐 +1 位作者 杨昭庆 余龙 《遗传》 CAS CSCD 北大核心 2001年第2期97-102,共6页
结合PCR扩增和cDNA文库筛选方法,本文从人胎盘cDNA文库中分离到一个与细胞周期调节有关的NEK6基因(GenBank登录号:AF087909)。该基因的cDNA序列全长1590 bp,编码一种由312氨基酸组成的蛋白质。在催化功能区,NEK6与小鼠的NEK1具有3... 结合PCR扩增和cDNA文库筛选方法,本文从人胎盘cDNA文库中分离到一个与细胞周期调节有关的NEK6基因(GenBank登录号:AF087909)。该基因的cDNA序列全长1590 bp,编码一种由312氨基酸组成的蛋白质。在催化功能区,NEK6与小鼠的NEK1具有39.32%的同源性。Northern 印迹证实在人体大多数组织中,NEK6基因均能表达1.6kb、3.0kb和9.5kb 3种mRNA转录物,其中1.6kb的表达产物可能是NEK6基因的实际表达产物,并且其在卵巢中的表达量明显高于睾丸组织。通过Radiation hybrid分析,NEK6基因进一步被定位于人9号染色体。结果初步显示,NEK6基因是哺乳动物NEK基因家族中的重要新成员,并可能在细胞分裂中发挥调节作用。 展开更多
关键词 细胞周期调节 NEK基因家族 RADIATION hybrid定位
在线阅读 下载PDF
同步辐射白光形貌术观察LiTaO_3晶体中的小角晶界 被引量:2
12
作者 魏景谦 胡小波 +6 位作者 王继扬 尹鑫 郭明 刘宏 刘耀岗 饶晓方 田玉莲 《人工晶体学报》 EI CAS CSCD 北大核心 2000年第S1期250-,共1页
关键词 LiTaO 3 crystal white beam synchrotron radiation topography sub grain bound ary MISORIENTATION
在线阅读 下载PDF
大别山高压-超高压片麻岩锆石的拉曼光谱学研究 被引量:3
13
作者 刘文元 刘景波 《岩石学报》 SCIE EI CAS CSCD 北大核心 2009年第9期2157-2164,共8页
对大别山高压-超高压片麻岩的锆石进行了激光拉曼探针、阴极发光(CL)、U-Pb年龄和U、Th等微量元素的测定分析。研究结果表明:锆石拉曼光谱1008cm^(-1)峰的半高宽普遍小于20cm^(-1),指示锆石结晶程度较好到中等程度的蜕晶化;早期继承锆... 对大别山高压-超高压片麻岩的锆石进行了激光拉曼探针、阴极发光(CL)、U-Pb年龄和U、Th等微量元素的测定分析。研究结果表明:锆石拉曼光谱1008cm^(-1)峰的半高宽普遍小于20cm^(-1),指示锆石结晶程度较好到中等程度的蜕晶化;早期继承锆石在三叠纪高压-超高压变质作用中经历了退火和重结晶作用,所受的放射性通量是从200Ma的早侏罗纪开始积累的,表明高压-超高压岩石在这一时间已出露地表;北大别白垩纪岩浆热事件对高压-超高压岩石的影响很小;大多数锆石数据都落在天然锆石的放射性破坏趋势(RDT)中,表明锆石在高压、超高压过程中基本发生了完全的重结晶。 展开更多
关键词 大别山 高压片麻岩 锆石拉曼光谱 激光拉曼探针 光谱学研究 DABIE Mountains HP-UHP 超高压岩石 metamorphic rocks radiation damage 超高压变质作用 trace elements 重结晶作用 放射性 during significant North DABIE Laser Raman the earth 阴极发光
在线阅读 下载PDF
候选门级辐射类群(candidate phyla radiation)细菌的生理生态与进化 被引量:1
14
作者 蒋建东 纪彦晗 王保战 《微生物学杂志》 CAS CSCD 2021年第6期1-10,共10页
候选门级辐射类群(candidate phyla radiation,CPR)细菌是一大支与绝大多数已知细菌系统发育地位、基因组大小、细胞形态和生理代谢特征具有显著差异的独特细菌类群。CPR细菌在地球上分布广泛,且群落多样性极高。然而,由于被发现较晚,... 候选门级辐射类群(candidate phyla radiation,CPR)细菌是一大支与绝大多数已知细菌系统发育地位、基因组大小、细胞形态和生理代谢特征具有显著差异的独特细菌类群。CPR细菌在地球上分布广泛,且群落多样性极高。然而,由于被发现较晚,人们对CPR细菌的认识还非常有限。针对CPR细菌发现历程、细胞形态、基因组学特征、生理代谢潜能、生态学功能、实验室纯培养以及遗传进化等方面进行系统地归纳与总结,以期为未来CPR细菌的生态生理和遗传进化等研究提供参考,进一步加深对地球微生物物种多样性和生命进化的认识。 展开更多
关键词 候选门级辐射类群(candidate phyla radiation CPR) CPR生理代谢与生态 CPR培养 寄生共生 生物地球化学循环
在线阅读 下载PDF
用快中子对燕山板栗辐射育种的研究
15
作者 张荫芬 蓝李桥 +3 位作者 周瑞英 杜绍权 韩光明 周锡侯 《北京师范大学学报(自然科学版)》 CAS 1988年第3期91-92,共2页
燕山板栗是我国名产,又是重要出口商品.历史上多为实生繁殖,果实性状良莠不齐,产量低,易感染种实霉烂病,影响商品价值.为了选育矮化、抗病、优质和丰产新品种,1976年我们与沙峪乡合作对板栗进行快中子辐射育种的研究.经过11年的工作,已... 燕山板栗是我国名产,又是重要出口商品.历史上多为实生繁殖,果实性状良莠不齐,产量低,易感染种实霉烂病,影响商品价值.为了选育矮化、抗病、优质和丰产新品种,1976年我们与沙峪乡合作对板栗进行快中子辐射育种的研究.经过11年的工作,已育成辐射76-6的3个优良品系,经繁殖和试种总产量平均提高40%,经济效益显著.该成果于1987年11月通过市级鉴定. 展开更多
关键词 Yanshan HAIRY CHESTNUT fast neutron radiation breed.
在线阅读 下载PDF
闪烁晶体——辐射探测用单晶
16
作者 殷之文 李培俊 《人工晶体学报》 EI CAS CSCD 北大核心 2000年第S1期2-,共1页
Phosphor converts excitation energy into light,resulting in lumminescence.The luminescence caused by radiation is called scintillation.Since the discovery of the scintillation in NaI∶Tl crystal in 1948,a series of ma... Phosphor converts excitation energy into light,resulting in lumminescence.The luminescence caused by radiation is called scintillation.Since the discovery of the scintillation in NaI∶Tl crystal in 1948,a series of materials with profound scintillating characteristics have been developed and have found wide applications for radiation detection in different fields such as nuclear physics,high energy physics,medical diagnostic imaging,geophysics exploration,clandestine explosive finding and many industrial measuring systems. Inorganic scintillating crystals have superior characteristics over their organic counterparts and some kinds of ceramics,glasses and powders that do have their scintillation effects.We will confine ourselves mainly to inorganic scintillating crystals in this presentation.. 展开更多
关键词 scintillation crystal radiation detection NaI:Tl BGO crystal PWO crystal BaF 2 C sI:Tl
在线阅读 下载PDF
基于GGE双标图的绿豆品种郑绿20号的丰产稳定性分析
17
作者 王保勤 李君霞 +1 位作者 周秋峰 黄长志 《湖北农业科学》 2024年第7期6-12,共7页
郑绿20号在2019年河南省绿豆[Vigna radiate(L.)R. Wilczek]新品种鉴定试验中,田间性状表现优良、抗性好、产量高,4个参试点均比对照郑绿8号增产。为了进一步考察郑绿20号的丰产稳产性,采用GGE双标图分析2019年河南省绿豆新品种鉴定试... 郑绿20号在2019年河南省绿豆[Vigna radiate(L.)R. Wilczek]新品种鉴定试验中,田间性状表现优良、抗性好、产量高,4个参试点均比对照郑绿8号增产。为了进一步考察郑绿20号的丰产稳产性,采用GGE双标图分析2019年河南省绿豆新品种鉴定试验参试品种的农艺及产量性状,并对绿豆品种9个性状进行变异性和相关性分析。结果表明,郑绿20号的主茎分枝数、单株荚数、株高、主茎节数变异系数在试验点中变异程度较大;主茎节数与生育期呈显著正相关,与产量呈显著负相关,与株高呈正相关;产量与主茎分枝数、单株荚数、荚长、荚粒数呈正相关。丰产稳定性分析结果表明,郑绿20号为适宜推广的兼具丰产性和稳定性的绿豆新品种。 展开更多
关键词 绿豆[Vigna radiate(L.)R.Wilczek] 郑绿20号 相关性 GGE双标图 丰产性 稳产性
在线阅读 下载PDF
医用介质部分加载波导辐射器
18
作者 江汉保 明德惠 邱鹏 《微波学报》 1987年第3期50-54,共5页
本文报导一种带有抗流槽的介质加载波导辐射器的研制结果。这种辐射器有相对均匀的加热图形,泄漏辐射较其它波导辐射器小,能满足临床治疗需要。用小探针法测试了这种辐射器在模拟肌肉内近场分布,结果与用温度计测出的辐射器加热后的温... 本文报导一种带有抗流槽的介质加载波导辐射器的研制结果。这种辐射器有相对均匀的加热图形,泄漏辐射较其它波导辐射器小,能满足临床治疗需要。用小探针法测试了这种辐射器在模拟肌肉内近场分布,结果与用温度计测出的辐射器加热后的温度分布基本一致。实验还表明波导辐射器的抗流槽对宽边的泄漏辐射有明显抑制,但对窄边的泄漏抑制作用不很明显。 展开更多
关键词 Waveguide radiator Microwave Hyperthermia Reducing microwave leakage
在线阅读 下载PDF
滆湖水体光学性质初步研究 被引量:10
19
作者 何尚卫 李勇 +1 位作者 赵海光 潘继征 《湖泊科学》 EI CAS CSCD 北大核心 2014年第5期707-712,共6页
基于2009年7月至2010年6月滆湖全湖15个采样点的水体光学参数及相关水质理化因子数据,分析滆湖水体周年光合有效辐射(PAR)衰减特性,以期为滆湖沉水植物生态修复提供相关水体光学资料.结果表明,滆湖水体PAR衰减系数(Kd)周年变化范围... 基于2009年7月至2010年6月滆湖全湖15个采样点的水体光学参数及相关水质理化因子数据,分析滆湖水体周年光合有效辐射(PAR)衰减特性,以期为滆湖沉水植物生态修复提供相关水体光学资料.结果表明,滆湖水体PAR衰减系数(Kd)周年变化范围为1.32~17.42 m-1.秋季Kd相对最小,平均值为2.35 m-1,变化范围为1.32 ~3.70 m-1;夏季Kd相对最大,平均值为6.23 m-1,变化范围为3.68~17.42 m-1.春、秋、冬季,滆湖水体真光层平均深度均满足沉水植物的生长需求,而在夏季滆湖水体真光层平均深度仅为0.84m,小于全湖平均水深(1.20 m),因此夏季PAR是限制沉水植物恢复的因子之一.滆湖水体Kd与透明度(SD)在秋、冬季的关系为:Kd =2.089 +0.705/SD.叶绿素a浓度和悬浮物浓度是影响滆湖水体Kd的重要因子之一. 展开更多
关键词 滆湖 沉水植物 真光层深度 photosynthetically ACTIVE RADIATION (PAR)
在线阅读 下载PDF
舰船辐射噪声的高阶统计量特征提取及特征压缩 被引量:7
20
作者 陈凤林 林正青 +3 位作者 彭圆 牟林 张凤珍 王磊 《应用声学》 CSCD 北大核心 2010年第6期466-470,共5页
提取了6类水中目标的11/2谱统计线谱特征和AR模型特征。实验结果表明基于11/2谱的统计线谱特征和AR模型特征有效的识别出了目标,达到了85%的综合识别率。最后利用主元分析技术对上述特征进行了压缩,在保持识别率的同时将特征维数从64维... 提取了6类水中目标的11/2谱统计线谱特征和AR模型特征。实验结果表明基于11/2谱的统计线谱特征和AR模型特征有效的识别出了目标,达到了85%的综合识别率。最后利用主元分析技术对上述特征进行了压缩,在保持识别率的同时将特征维数从64维压缩至34维,有利于工程上的实现。 展开更多
关键词 舰船辐射噪声 高阶统计量 特征提取 特征压缩 radiated noise SHIP statistical characteristics 模型特征 主元分析技术 特征和 识别率 线谱 特征维数 水中目标 实验结果 谱统计 综合 工程
在线阅读 下载PDF
上一页 1 2 6 下一页 到第
使用帮助 返回顶部