期刊文献+
共找到27篇文章
< 1 2 >
每页显示 20 50 100
Fabrication of arbitrarily apodized fiber Bragg gratings with narrow bandwidth
1
作者 吕昌贵 恽斌峰 崔一平 《Journal of Southeast University(English Edition)》 EI CAS 2009年第1期23-25,共3页
A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings( FBGs) with narrow bandwidth is demonstrated by controlling the total ultra violet (UV)... A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings( FBGs) with narrow bandwidth is demonstrated by controlling the total ultra violet (UV) irradiation along the grating by varying the speed of a translation stage. The UV source used is a stable continuous intracavity frequency-doubled argonion laser. The parameters (such as length, apodization profile, average index change)of FBGs can be easily changed with this method. The total UV irradiation is kept constant in the doubleexposure process because of the precise control of the exposure time, which ensures that the apodized FBG's bandwidth can be extremely narrow. The full width at half maximum (FWHM) bandwidth of the 2-cm-long apodized FBG fabricated by this method is 0. 15 nm with a maximum reflectivity of more than 95%. 展开更多
关键词 fiber Bragg grating APODIZATION double exposure
在线阅读 下载PDF
An apodized cubic phase mask used in a wavefront coding system to extend the depth of field
2
作者 Lina Zhu Fei Li +1 位作者 Zeyu Huang Tingyu Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第5期422-428,共7页
The point spread function(PSF)caused by a wavefront coding system with a cubic phase mask has big side-lobes which leads to bad image restoration.This paper proposes a novel apodized cubic phase mask to suppress the s... The point spread function(PSF)caused by a wavefront coding system with a cubic phase mask has big side-lobes which leads to bad image restoration.This paper proposes a novel apodized cubic phase mask to suppress the side-lobes of the PSF.Simulated annealing algorithm is used to optimize the cubic and the truncation parameter of the phase mask.The system with the novel phase mask has better performance in the modulation transfer function(MTF)especially in low-and-medium spatial frequency region.The simulation results show that the restored images with the novel phase mask are superior to the one with the classic cubic phase mask in contrast and ringing effect.The experimental results show that the side-lobes of the PSF are suppressed by using the apodized cubic phase mask. 展开更多
关键词 apodized cubic phase mask wavefront coding depth of field image restoration
原文传递
Novel Apodized Fiber Bragg GratingApplied for Medical Sensors:Performance Investigation 被引量:1
3
作者 Ramya Arumugam Ramamoorthy Kumar +3 位作者 Samiappan Dhanalakshmi Khin Wee Lai Lei Jiao Xiang Wu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第4期301-323,共23页
Sensors play an important role in shaping and monitoring human health.Exploration of methods to use Fiber Bragg Grating(FBG)with enhanced sensitivity has attracted great interest in the field of medical research.In th... Sensors play an important role in shaping and monitoring human health.Exploration of methods to use Fiber Bragg Grating(FBG)with enhanced sensitivity has attracted great interest in the field of medical research.In this paper,a novel apodization function is proposed and performance evaluation and optimization of the same have been made.A comparison was conducted between various existing apodization functions and the proposed one based on optical characteristics and sensor parameters.The results evince the implementation of the proposed apodization function for vital sign measurement.The optical characteristics considered for evaluation are Peak Resonance Reflectivity level,Side Lobes Reflectivity level and FullWidth HalfMaximum(FWHM).The proposed novel apodization novel function has better FWHM,which is narrower than the FWHM of uniform FBG.Sensor characteristics like a quality parameter,detection accuracy and sensitivity also show improvement.The proposed novel apodization function is demonstrated to have a better shift in wavelength in terms of temperature and pulse measurement than the existing functions.The sensitivity of the proposed apodized function is enhanced with a Poly-dimethylsiloxane coating of varying thickness,which is 6 times and 5.14 times greater than uniform Fiber Bragg grating and FBG with the proposed novel apodization function,respectively,enhancing its utilization in the field of medicine. 展开更多
关键词 Fiber bragg grating APODIZATION optical sensing TEMPERATURE STRAIN sensitivity
在线阅读 下载PDF
Resolution of Two Unequally Bright Points of Apodized Optical Systems with Asymmetric Circular Antenna Arrays 被引量:1
4
作者 Andra Naresh Kumar Reddy Pagolu Shailaja Dasari Karuna Sagar 《Optics and Photonics Journal》 2016年第3期39-46,共8页
Sparrow criterion of resolution is used for assessment of the resolution of two object points of apodized optical systems under incoherent illumination of light. Semicircular arrays of circular aperture with discrete ... Sparrow criterion of resolution is used for assessment of the resolution of two object points of apodized optical systems under incoherent illumination of light. Semicircular arrays of circular aperture with discrete asymmetric apodization have suppressed side-lobes and a narrower central peak in the image plane termed as PSF good side on alternatively the right and left of the strong spectral point facilitates to detect the presence of weak spectral point in the vicinity of bright spectral point. The results of investigations on optimum discrete pupil function with semicircular arrays on the intensity distributions in the composite image of two object points with widely varying in their intensities under various degree of coherence of illumination have been studied. Sparrow resolution limits and the dip in central intensity as function of degree of coherence of the illumination (γ), intensity ratio (α), degree of asymmetric apodization (b) and number of discrete elements in semicircular array (n). The efficiency of aperture functions is discussed in terms of these parameters. Pupil function capabilities in redistribution of energy in composite image of two object points in close vicinity have been verified for different considerations. Current study has found an improvement in two-point resolution characteristics compared to their unapodized counter part. Fourier analytical properties of an optical system are presented for evaluation of this practical problem. 展开更多
关键词 Complementary Pupil Function Diffraction Two-Point Resolution Discrete Asymmetric Apodization Degree of Coherence Sparrow Limit Intensity Ratio SUPERRESOLUTION
在线阅读 下载PDF
双峰驼APOD的克隆、生物信息学分析及在附睾中的表达与定位
5
作者 崔爱利 王文静 +6 位作者 黄雪 颜秋 李天安 南京宏 张勇 赵兴绪 王琪 《中国兽医学报》 北大核心 2025年第4期752-759,共8页
载脂蛋白D(apolipoproteinD,APOD)广泛存在于动物各组织,参与机体的生殖调控。为探究APOD在双峰驼附睾中的表达规律及其对精子成熟的调控作用,本试验以发情期及乏情期双峰驼附睾为材料,首先克隆APOD的编码序列(CDS)区全序列,利用ProPara... 载脂蛋白D(apolipoproteinD,APOD)广泛存在于动物各组织,参与机体的生殖调控。为探究APOD在双峰驼附睾中的表达规律及其对精子成熟的调控作用,本试验以发情期及乏情期双峰驼附睾为材料,首先克隆APOD的编码序列(CDS)区全序列,利用ProParam、SOPMA、SWISS-MODEL和MEGA7.0等软件分析其理化特性,同时采用qRT-PCR、蛋白免疫印迹(Westernblot)及免疫组织化学法(IHC)检测APOD在附睾中的表达及分布规律。克隆结果显示,APOD基因的CDS区长度为624bp,编码207个氨基酸,双峰驼APOD序列与羊驼的核苷酸和氨基酸序列存在高度保守性,同源性近,与麋鹿的同源性最低。qRT-PCR结果显示,乏情期附睾头、体及尾APOD的mRNA水平显著高于发情期(P<0.01);Westernblot结果显示,乏情期附睾头及附睾体的APOD蛋白表达与mRNA表达趋势相似,但乏情期附睾尾APOD的表达水平与mRNA表达水平相反(P<0.05)。H&E及IHC结果显示,发情期和乏情期附睾组织有明显差异,且APOD在附睾上皮细胞、平滑肌细胞、精子及结缔组织均有不同程度的阳性反应。结果提示APOD可能参与发情期及乏情期精子的成熟过程,为进一步探究APOD参与季节性发情的调控机制提供依据。 展开更多
关键词 双峰驼 发情期 乏情期 附睾 APOD
原文传递
APOD在口腔鳞状细胞癌中的表达以及与免疫浸润的相关性分析
6
作者 朱慧 《实用口腔医学杂志》 北大核心 2025年第3期386-391,共6页
目的:分析APOD在口腔鳞状细胞癌(OSCC)中的表达及其与免疫细胞浸润之间的关系,并探讨APOD潜在的生物学功能。方法:从TCGA和GEO数据库分别下载OSCC相关表达谱数据,通过Mann-Whitney U检验和T检验分析非配对样本和配对样本中APOD的表达。... 目的:分析APOD在口腔鳞状细胞癌(OSCC)中的表达及其与免疫细胞浸润之间的关系,并探讨APOD潜在的生物学功能。方法:从TCGA和GEO数据库分别下载OSCC相关表达谱数据,通过Mann-Whitney U检验和T检验分析非配对样本和配对样本中APOD的表达。采用logistic回归分析APOD的表达与临床病理特征间的关系,通过Kaplan-Meier分析APOD表达与OSCC患者预后的关系。通过R分析APOD表达与免疫细胞浸润以及免疫检查点的相关性,并通过基因富集分析探讨APOD在OSCC中潜在的生物学作用。结果:APOD在OSCC肿瘤组织中低表达(P<0.001),受试者工作曲线的曲线下面积为0.87。APOD表达与临床分期(P=0.038)和T分期(P=0.018)负相关,与组织学分级(P=0.005)和有无淋巴血管侵犯(P=0.015)正相关。Kaplan-Meier分析表明高表达APOD与OSCC患者预后差相关。免疫细胞浸润分析发现大部分免疫细胞浸润丰度与APOD的表达正相关。APOD的表达与PD1、CTLA4、LAG3、TIGIT、CD48和TIM3均正相关。功能富集分析结果提示APOD表达与免疫反应、FCERI介导的NF-κB激活信号通路等相关。结论:APOD有望成为OSCC患者诊断和预后的生物标志物。同时,本研究为OSCC免疫治疗提供了新思路。 展开更多
关键词 APOD 口腔鳞状细胞癌 免疫浸润 预后
暂未订购
Apodized silicon photonic grating couplers for mode-order conversion 被引量:3
7
作者 IOSIF DEMIRTZIOGLOU COSIMO LACAVA +4 位作者 ABDUL SHAKOOR ALI KHOKHAR YONGMIN JUNG DAVID J.THOMSON PERIKLIS PETROPOULOS 《Photonics Research》 SCIE EI CSCD 2019年第9期1036-1041,共6页
An out-of-plane silicon grating coupler capable of mode-order conversion at the chip–fiber interface is designed and fabricated. Optimization of the structure is performed through finite-difference time-domain simula... An out-of-plane silicon grating coupler capable of mode-order conversion at the chip–fiber interface is designed and fabricated. Optimization of the structure is performed through finite-difference time-domain simulations,and the final device is characterized through far-field profile and transmission measurements. A coupling loss of 3.1 dB to a commercial two-mode fiber is measured for a single TE0→ LP11 mode conversion grating, which includes a conversion penalty of 1.3 dB. Far-field patterns of the excited LP11 mode profile are also reported. 展开更多
关键词 apodized SILICON PHOTONIC GRATING COUPLERS for mode-order CONVERSION
原文传递
Microglial ApoD-induced NLRC4 inflammasome activation promotes Alzheimer's disease progression
8
作者 Yaliang Yu Jianzhou Lv +4 位作者 Dan Ma Ya Han Yaheng Zhang Shanlong Wang Zhitao Wang 《Animal Models and Experimental Medicine》 2025年第5期773-783,共11页
Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Wel... Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Well-balanced neuronal-microglial interactions are essential for brain functions.However,determining the role of microglia—the primary immune cells in the brain—in neuroinflammation in AD and the associated molecular basis has been challenging.Methods:Inflammatory factors in the sera of AD patients were detected and their association with microglia activation was analyzed.The mechanism for microglial inflammation was investigated.IL6 and TNF-α were found to be significantly increased in the AD stage.Results:Our analysis revealed that microglia were extensively activated in AD cerebra,releasing sufficient amounts of cytokines to impair the neural stem cells(NSCs)function.Moreover,the ApoD-induced NLRC4 inflammasome was activated in microglia,which gave rise to the proinflammatory phenotype.Targeting the microglial ApoD promoted NSC self-renewal and inhibited neuron apoptosis.These findings demonstrate the critical role of ApoD in microglial inflammasome activation,and for the first time reveal that microglia-induced inflammation suppresses neuronal proliferation.Conclusion:Our studies establish the cellular basis for microglia activation in AD progression and shed light on cellular interactions important for AD treatment. 展开更多
关键词 Alzheimer's disease ApoD MICROGLIA NLRC4 inflammasome
暂未订购
Effects Of Average Index Variation in Apodized Long-Period Fiber Gratings
9
作者 Yanju GU Kin Seng CHIANG 《Photonic Sensors》 SCIE EI CAS 2013年第2期102-111,共10页
We analyze the effects of average index variation on the transmission characteristics of an index-apodized long-period fiber grating (LPFG) by the transfer matrix method and study how these effects depend on the gra... We analyze the effects of average index variation on the transmission characteristics of an index-apodized long-period fiber grating (LPFG) by the transfer matrix method and study how these effects depend on the grating length, the grating profile, the modal dispersion factor, and the duty cycle of the index modulation. Apart from shifting the resonance wavelength and modifying the rejection band, average index variation can give rise to significant side lobes that may appear on the short-wavelength or long-wavelength side of the rejection band, depending on the signs of the average index change and the modal dispersion factor. Our results provide general guidance for the writing of LPFGs for the minimization of side lobes. Our analysis compares well with published experimental results and should be useful for the design and fabrication of LPFGs. 展开更多
关键词 APODIZATION fiber grating long-period fiber grating (LPFG) optical fiber sensor optical filter transfer matrix method
原文传递
A high-contrast imaging coronagraph for segmented-mirror large aperture telescopes using a spatial light modulator
10
作者 Jiangpei Dou Huanyu Dong 《Astronomical Techniques and Instruments》 CSCD 2024年第3期166-170,共5页
The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the... The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the performance of high-contrast coronagraph.To solve this problem,we propose a coronagraph system based on a single liquid crystal spatial light modulator(SLM).This spatial light modulator is used for amplitude apodization,and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent(SPGD)algorithm to control the spatial light modulator,which is based on point spread function(PSF)sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function.The system delivers a contrast in the order of 10−6,and shows excellent potential to be used in current and future large aperture telescopes,both on the ground and in space. 展开更多
关键词 Liquid crystal spatial light modulator Amplitude apodized pupil Large aperture telescopes
在线阅读 下载PDF
腋臭患者大汗腺中ApoD和AR的表达水平与气味强度间的关系 被引量:5
11
作者 栗颖利 王克华 +2 位作者 李江 邢新 陈辉 《现代生物医学进展》 CAS 2014年第30期5837-5840,共4页
目的:明确大汗腺组织中ApoD和AR的表达水平与腋臭患者散发出气味间的关系,阐明两者在腋臭发病中的作用,为腋臭的临床治疗和干预奠定基础。方法:收集在我院整形外科就诊的腋臭病人腋下皮肤组织标本41例。手术前由3名医生共同判断患者腋... 目的:明确大汗腺组织中ApoD和AR的表达水平与腋臭患者散发出气味间的关系,阐明两者在腋臭发病中的作用,为腋臭的临床治疗和干预奠定基础。方法:收集在我院整形外科就诊的腋臭病人腋下皮肤组织标本41例。手术前由3名医生共同判断患者腋下气味强度,按照能在≤1 m、≤3 m、≤5 m距离闻及气味把患者分为轻、中、重三组。随机抽取各组标本组织块进行RT-PCR检测,测定ApoD和AR在大汗腺组织中的含量。结果:根据气味强度判定标准,轻、中和重3组患者人数分别为:7人、11人和23人。按照AB 7500 Real-Time PCR系统分析结果所示ApoD相对表达量的等级与气味强度之间有线性关系(P<0.05),ApoD相对表达量的等级随着气味强度的增加而升高;AR相对表达量的等级与气味强度之间有线性关系(P<0.05),随着气味强度的增加而升高。结论:ApoD和AR的表达量与腋臭气味强度之间有着密切的联系。进一步证实AR可调节大汗腺组织ApoD的表达,为明确腋臭的发病机制提供了理论依据。 展开更多
关键词 腋臭 大汗腺 气味 ApoD AR
原文传递
腋臭患者ApoD表达变化及其分子机制的研究 被引量:8
12
作者 陈辉 栗颖利 +1 位作者 杜洁 王芳芳 《中国美容医学》 CAS 2012年第11期1956-1960,共5页
目的:观察与E-3M2H分泌相关的载脂蛋白D(ApoD)和雄激素受体AR在腋臭患者的大汗腺的表达与正常人的差异,探讨导致腋臭患者ApoD表达异常的原因。方法:收集4例正常对照和10例腋臭患者的组织样本,采用免疫组化、realtime-PCR和western-blot... 目的:观察与E-3M2H分泌相关的载脂蛋白D(ApoD)和雄激素受体AR在腋臭患者的大汗腺的表达与正常人的差异,探讨导致腋臭患者ApoD表达异常的原因。方法:收集4例正常对照和10例腋臭患者的组织样本,采用免疫组化、realtime-PCR和western-blot检测腋臭患者组织中ApoD、AR的表达水平,通过细胞培养和激素诱导,分析AR信号调控ApoD表达的可能性,并阐明JNK1信号通路在其中扮演的作用。结果:实验发现ApoD和AR在腋臭患者的大汗腺的表达与正常人有明显的差异,腋臭患者中ApoD表达几乎是正常人的2倍;而腋臭患者中AR表达也明显增加,与此同时,腋臭患者中JNK1活化增强。雄激素可以增强正常人ApoD的表达,且该过程中同样伴有JNK1活化;抑制JNK1活化,可以降低腋臭患者和雄激素诱导的ApoD的表达。结论:ApoD表达增加是腋臭患者的重要分子特征,其表达增加与AR信号增强密切相关。JNK1的活化是腋臭患者和雄激素导致的ApoD表达增加的重要原因,抑制JNK1活化,可以抑制腋臭患者内源和雄激素诱导的ApoD的表达。 展开更多
关键词 腋臭 载脂蛋白D(ApoD) JNK 表达调控
暂未订购
基于最优三次谐波注入的改进APOD调制 被引量:2
13
作者 武亮亮 唐芬 +3 位作者 陈鹏飞 梁家志 王玮 Poh Chiang Loh 《电网技术》 EI CSCD 北大核心 2020年第4期1257-1266,共10页
在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,AP... 在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,APOD)所需滤波器总电感量较大。针对以上问题,在定量分析比较PD和APOD两种调制方式谐波分布及边带谐波扩散特点的基础上,给出了两种调制方式总电感量约束方程。为保有APOD调制谐波分布集中优点的同时减小APOD总电感量需求,研究了一种基于最优三次谐波注入的改进APOD调制策略,分析了不同三次谐波注入量对APOD电压谐波分布及总电感量需求的影响,进而给出了以总电感量需求最小为目标的三次谐波最优注入量的计算方法,该方法可以实时根据当前调制度自动计算需要注入的三次谐波最优幅值,实现最优三次谐波的在线注入。最后,仿真和实验结果表明,所提策略不仅可以有效地避开高阶滤波器的谐振点,而且可有效降低主导谐波电压幅值,从而减小所需滤波器总电感量。 展开更多
关键词 APOD调制 三次谐波注入 谐波分布 LCL滤波器
原文传递
APOD卫星大气密度数据处理与标校 被引量:9
14
作者 李勰 徐寄遥 +4 位作者 唐歌实 陈光明 满海钧 刘舒莳 李永平 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2018年第9期3567-3576,共10页
APOD卫星是我国首颗以热层大气密度探测与精密定轨为科学目标的微纳卫星,搭载大气密度探测器、双频GNSS接收机等载荷,于2015年9月20日发射入轨,2015年10月27日进入轨道高度460km、轨道倾角97.4°、降交点地方时6∶20的工作轨道,各... APOD卫星是我国首颗以热层大气密度探测与精密定轨为科学目标的微纳卫星,搭载大气密度探测器、双频GNSS接收机等载荷,于2015年9月20日发射入轨,2015年10月27日进入轨道高度460km、轨道倾角97.4°、降交点地方时6∶20的工作轨道,各项载荷随即展开例行观测.本文给出了APOD卫星大气密度探测器的基本原理和数据处理流程,采用基于双行根数(TLE)反演获取的密度数据,对2015年12月至2016年12月的就位探测数据进行了标校,并与经验密度模式进行了比较.结果表明,反演密度与APOD卫星就位探测数据的线性相关性达到0.943,采用线性拟合与二次函数拟合的残差水平基本相当.两种不同方法标校密度相对于NRLMSIS00模式日均值误差的均值和标准偏差为10.1%、18.2%和5.1%、17.1%,二次函数标校略优于线性标校;相对于JB2008模式日均值误差的均值和标准偏差为0.6%、14.9%和3.9%、16.9%,线性标校略优于二次函数标校.总体而言,APOD卫星大气密度就位探测数据与常用经验模式精度基本一致,可为开展大气密度变化规律及应用研究提供数据基础. 展开更多
关键词 APOD卫星 大气密度探测 处理 标校
在线阅读 下载PDF
ApoD对鸡成肌细胞增殖与分化的调控机制研究 被引量:1
15
作者 莫家伟 黎镇晖 +1 位作者 王芷筠 聂庆华 《中国家禽》 北大核心 2022年第12期8-13,共6页
为揭示ApoD对鸡成肌细胞增殖与分化的调控作用,研究在鸡原代成肌细胞中分别过表达和干扰ApoD基因,检测胞内活性氧(ROS)和丙二醛(MDA)含量,同时通过流式细胞术、CCK-8、qRT-PCR及免疫印迹等试验探究其对细胞增殖和分化的影响。结果显示:A... 为揭示ApoD对鸡成肌细胞增殖与分化的调控作用,研究在鸡原代成肌细胞中分别过表达和干扰ApoD基因,检测胞内活性氧(ROS)和丙二醛(MDA)含量,同时通过流式细胞术、CCK-8、qRT-PCR及免疫印迹等试验探究其对细胞增殖和分化的影响。结果显示:ApoD降低胞内ROS和MDA含量,促进鸡原代成肌细胞增殖;同时,ApoD下调肌肉萎缩标志基因Atrogin1和MuRF1的表达,上调生肌因子MyoD、MyoG和MyHC的表达,从而促进鸡原代成肌细胞分化。研究结果提示ApoD通过降低胞内ROS含量、降低Atrogin1对MyoD的泛素化降解作用以及MuRF1对MyHC的抑制作用,促进鸡成肌细胞增殖与分化。 展开更多
关键词 ApoD 活性氧 细胞增殖 细胞分化
原文传递
A high-contrast coronagraph for direct imaging of Earth-like exoplanets: design and test 被引量:3
16
作者 Cheng-Chao Liu De-Qing Ren +5 位作者 Jiang-Pei Dou Yong-Tian Zhu Xi Zhang Gang Zhao Zhen Wu Rui Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第3期453-460,共8页
A high-contrast coronagraph for direct imaging of an Earth-like exoplanet at the visible band needs a contrast of 10^-10 at a small angular separation of 4λ/D or less. Here we report our recent laboratory experiment ... A high-contrast coronagraph for direct imaging of an Earth-like exoplanet at the visible band needs a contrast of 10^-10 at a small angular separation of 4λ/D or less. Here we report our recent laboratory experiment that approaches these lim- its. Our test of a high-contrast imaging coronagraph is based on our step-transmission apodized filter. To achieve this goal, we use a liquid crystal array as a phase correc- tor to create a dark hole based on our dedicated algorithm. We have suppressed the diffraction and speckle noise near the point image of a star to a level of 1.68 × 10^-9 at 4λ/D, which can be used for direct imaging of Jupiter-like exoplanets. This demon- strates that a telescope incorporating a high-contrast coronagraph in space has the potential to detect and characterize Earth-like planets. 展开更多
关键词 instrumentation: coronagraph liquid crystal array -- techniques:apodization -- methods: laboratory
在线阅读 下载PDF
High-contrast coronagraph for ground-based imaging of Jupiter-like planets 被引量:2
17
作者 Jiang-Pei Dou De-Qing Ren Yong-Tian Zhu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2010年第2期189-198,共10页
We propose a high-contrast coronagraph for direct imaging of young Jupiter-like planets orbiting nearby bright stars. The coronagraph employs a step- transmission filter in which the intensity is apodized with a finit... We propose a high-contrast coronagraph for direct imaging of young Jupiter-like planets orbiting nearby bright stars. The coronagraph employs a step- transmission filter in which the intensity is apodized with a finite number of steps with identical transmission in each step. It should be installed on a large ground-based telescope equipped with a state-of-the-art adaptive optics system. In this case, contrast ratios around 10-6 should be accessible within 0.1 arcsec of the central star. In recent progress, a coronagraph with a circular apodizing filter has been developed, which can be used for a ground-based telescope with a central obstruction and spider structure. It is shown that ground-based direct imaging of Jupiter-like planets is promising with current technology. 展开更多
关键词 instrumentation: high angular resolution- methods: laboratory numer- ical -- techniques: coronagraphy apodization -- planetary systems
在线阅读 下载PDF
Numerical investigation of slow solitons in Bragg gratings with a hyperbolic tangent apodization
18
作者 王葵如 程洁琳 +1 位作者 桑新柱 陈功 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第3期268-273,共6页
This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle se... This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle section in order to obtain slower solitons. Optical fibre soliton but not Bragg grating soliton is used as input pulse in the discussion, which is much more approximate to the light source for the practical purpose. We discuss in detail the effects of the soliton's velocity with some parameters in the process of transmission. The results show that by choosing special parameters, one can make the soliton slow-down with a little distortion and energy decay and obtain tunable time-delay on a small scale. 展开更多
关键词 fibre grating slow light SOLITON hyperbolic tangent apodization
原文传递
Simulating Ultrasound Reflections Using Rayleigh Integral Method in Complex Biological Media
19
作者 MalakNasser Walid Hassan +1 位作者 Ali Hage-Diab Souheil Hakeem 《Journal of Life Sciences》 2013年第12期1288-1296,共9页
This paper exploits the Rayleigh integral method to simulate the propagation of transmitted ultrasonic waves and received echoes through various media. Performed simulations study the effect of apodization using diffe... This paper exploits the Rayleigh integral method to simulate the propagation of transmitted ultrasonic waves and received echoes through various media. Performed simulations study the effect of apodization using different types of windows and the effect of medium properties on the reflections obtained. All estimations are done using the Rayleigh integral method simplified by the Fresnel approximation. Five different interfaces are considered: tissue-bone-tissue, tissue-fat-bone, fat-muscle-bone, air-fat-bone and water-fat-bone. The apodization simulations show that the hamming window is more efficient than the rectangular and triangular windows for obtaining a more consistent beam. In the second set of simulations, reflections are mapped with respect to the depth from which these reflections are generated. It demonstrates that the solid and water media allow for the attainment of echoes from deeper regions as compared to the air medium. Matlab is used as the simulation framework. 展开更多
关键词 ULTRASOUND REFLECTIONS Rayleigh integral apodization.
在线阅读 下载PDF
The role and regulation mechanisms of APOD in prognosis and subtyping of breast cancer
20
作者 Chen-Fei Zhao Shi-Liang Chen +5 位作者 Cong Wang Dan Hu Xiao-Xiao Yang Shi-Yuan Tong Yi-Bo He Zhe-Zhong Zhang 《Medical Data Mining》 2023年第3期39-49,共11页
Background:Breast cancer is the most common cancer,and abnormal lipid metabolism is associated with cancer.APOD expression is negatively correlated with various cancers related to tumor prognosis.DNA methylation may a... Background:Breast cancer is the most common cancer,and abnormal lipid metabolism is associated with cancer.APOD expression is negatively correlated with various cancers related to tumor prognosis.DNA methylation may affect APOD expression.Therefore,this paper aims to investigate the significance of APOD expression and APOD DNA methylation in breast cancer.Methods:This study utilized comprehensive bioinformatics analysis of APOD using Gene Expression database of Normal and Tumor tissues 2,UCSC Xena,etc.Clinical and survival information obtained from the The Cancer Genome Atlas and Gene Expression Omnibus datasets were extracted for data mining.Results:The correlation between APOD and breast cancer was examined,along with the connection between APOD DNA methylation and APOD expression.In the The Cancer Genome Atlas cohort,as well as GSE31448 and GSE65194 datasets,APOD expression decreased in breast cancer(P<0.0001).Clinical feature analysis results showed that APOD expression was correlated with the PAM50 subtype,with the lowest expression in the Basal subtype(P<0.0001).High APOD expression is a good prognostic marker for breast cancer(HR=0.71,P=0.037).APOD methylation level was significantly negatively correlated with expression level(R=−0.4770,P<0.001),and cg15231202,cg23720929,and cg05624196 were important regulatory targets.High APOD expression was associated with higher metabolism and extracellular matrix scores.Conclusion:APOD is an independent prognostic marker for breast cancer and is regulated by DNA methylation to modulate mRNA expression. 展开更多
关键词 breast cancer APOD DNA methylation BIOINFORMATICS PROGNOSIS PAM50 subtype
暂未订购
上一页 1 2 下一页 到第
使用帮助 返回顶部