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Crystallization and Melting Behaviors of Polyolefin Elastomer Studied by Fast Scanning Chip Calorimetry
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作者 Wen-Yan Wang Yan-Feng Jiang +5 位作者 Xing-Long Zhao Deng-Fei Wang Teng-Jie Ge Dimitri A.Ivanov Ying Lu Yong-Feng Men 《Chinese Journal of Polymer Science》 2025年第8期1458-1467,共10页
The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling ... The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling to low temperatures cannot be inhibited under the largest efficient cooling rate employed in the current work.Thus,the isothermal crystallization of POE samples was limited to a narrow temperature range.When the POE samples were cooled to a certain temperature below the non-isothermal crystallization temperature for crystallization,a crystallization time dependent melting peak appeared in the low temperature region besides the high temperature melting peak originated from the non-isothermal crystallization.This low temperature melting peak was arisen from the melting of crystals isothermally crystallized at the selected crystallization temperature.At each crystallization temperature,the lengths of crystallizable segments were different,thus,the low melting peak increased with increasing the crystallization temperature.In terms of the high melting peak attributed to the non-isothermally crystallized crystals,it somehow decreased with increasing crystallization time and then became constant with further increasing crystallization time at the selected crystallization temperature.This could be explained by the fact that the crystallizable sequences with longer length would nucleate and crystallize first to form thicker crystals during cooling.The subsequent crystallization contributed by the shorter crystallizable sequences will result in the formation of thinner crystals,causing the melting peak to shift to the lower temperature. 展开更多
关键词 Polyolefin elastomer Successive self-nucleation and annealing(SSA) Crystallization fast scanning chip calorimetry(FSC) Melting
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A Leukocyte image fast scanning based on max–min distance clustering 被引量:1
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作者 Yapin Wang Yiping Cao 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2016年第6期50-57,共8页
A leukocyte image fast scanning method based on max min distance clustering is proposed.Because of the lower proportion and uneven distribution of leukocytes in human peripheral blood,there will not be any leukocyte i... A leukocyte image fast scanning method based on max min distance clustering is proposed.Because of the lower proportion and uneven distribution of leukocytes in human peripheral blood,there will not be any leukocyte in lager quantity of the captured images if we directly scan the blood smear along an ordinary zigzag scanning routine with high power(100^(x))objective.Due to the larger field of view of low power(10^(x))objective,the captured low power blood smear images can be used to locate leukocytes.All of the located positions make up a specific routine,if we scan the blood smear along this routine with high power objective,there will be definitely leukocytes in almost all of the captured images.Considering the number of captured images is still large and some leukocytes may be redundantly captured twice or more,a leukocyte clustering method based on max-min distance clustering is developed to reduce the total number of captured images as well as the number of redundantly captured leukocytes.This method can improve the scanning eficiency obviously.The experimental results show that the proposed method can shorten scanning time from 8.0-14.0min to 2.54.0 min while extracting 110 nonredundant individual high power leukocyte images. 展开更多
关键词 Leukocyte image fast scanning scanning routine max-min distance clustering window clustering microscopic imaging image segmentation
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Fast Scanning Calorimetry of Semicrystalline Polymers:From Fundamental Research to Industrial Applications
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作者 Rui Zhang Mengxue Du +3 位作者 Katalee Jariyavidyanont René Androsch Evgeny Zhuravlev Christoph Schick 《Accounts of Materials Research》 2025年第5期627-637,共11页
CONSPECTUS:The global production of polymer products currently exceeds 400 megatons annually.To ensure effective and environmentally responsible use of this vast resource,optimizing the properties of the products is e... CONSPECTUS:The global production of polymer products currently exceeds 400 megatons annually.To ensure effective and environmentally responsible use of this vast resource,optimizing the properties of the products is essential.Achieving this requires precise control over the internal structure of the polymers.Depending on the materials used,polymers can exist in either amorphous or semicrystalline states.Processing is often performed from the melt state,and the cooling rate plays a critical role in determining whether amorphous or semicrystalline products are formed alongside other process parameters such as the pressure and shear rates.To understand the structure formation during processing,knowledge of the cooling rate dependence is therefore essential.As all of these processes are associated with thermal effects,calorimetry is universally applicable here.Achieving cooling rates that are comparable to those during processing has therefore long been a challenge for calorimetric measurement methods.With the introduction of MEMS-based chip sensors for calorimetry,significant progress has been made in reproducing conditions,such as those that occur during injection molding.These special calorimetric techniques are often summarized under the terms Fast Scanning Calorimetry(FSC)or Nanocalorimetry,alluding to nanogram samples.Investigations with controlled cooling rates of up to 1×10^(6)K/s are now possible with special chip sensors and allow the study of material properties under extreme conditions.Technological issues such as crystallization and nucleation processes under processrelevant conditions can be investigated in most cases with commercial devices that achieve cooling rates of 10^(4)K/s.The cooling rates to be considered in relation to various manufacturing processes are discussed here,and the functionality of corresponding chip calorimeters is briefly presented.Since calorimetry only provides general information on the processes taking place in the material,but not directly on the resulting structures,combinations of FSC and methods for structure elucidation,e.g.,microscopy,are also presented.The main part of this Account deals with contributions of FSC to the understanding of crystallization processes under conditions as they occur in different manufacturing processes.Not only the influence of the cooling rate during injection molding but also the multistage cooling by chill rolls during film production is considered.Thanks to the high scanning rate of FSC,needed to bypass crystallization in the low-supercooling temperature range where heterogeneous nucleation dominates,an important aspect of polymer structure formation-homogeneous crystal nucleation-has become accessible for direct observation.Homogeneous nucleation can occur not only during cooling but also during storage at temperatures close to or even below the glass transition temperature in the amorphous state.The possibilities of FSC for the generation and investigation of amorphous states are illustrated by an example.Finally,possible further developments of FSC and expected further applications of this fascinating technology are considered. 展开更多
关键词 amorphous states precise control internal structure manufacturing processes semicrystalline polymers NUCLEATION CRYSTALLIZATION properties products fast scanning calorimetry
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Viscosity in metallic supercooled liquids obtained by fast scanning calorimetry and its application to thermoplastic forming
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作者 Min Liu Zheng Wang +2 位作者 Yijun Ding Senkuan Meng Lina Hu 《Science China(Physics,Mechanics & Astronomy)》 2025年第6期23-32,共10页
Viscosity is a crucial dynamic property for alloy liquids.For alloy liquids with glass-forming ability,their viscosity undergoes a change of more than ten orders of magnitude upon cooling,and eventually,a transition f... Viscosity is a crucial dynamic property for alloy liquids.For alloy liquids with glass-forming ability,their viscosity undergoes a change of more than ten orders of magnitude upon cooling,and eventually,a transition from liquid to glassy state occurs when viscosity reaches 1012 Pa s.Nevertheless,the viscosity measurement in the supercooled liquid region(SLR)has been an experimental challenge.Here,in this work,by combining conventional and fast scanning calorimeters,the accurate viscosity of supercooled liquids for Au_(49)Ag_(5.5)Pd_(2.3)Cu_(26.9)Si_(16.3) and Zr_(44)Ti_(11)Cu_(10)Ni_(10)Be_(25) metallic glasses(MGs)was measured over a wide viscosity range of 10^(6)-10^(12) Pa s.Moreover,the viscosity range of 10^(6)-10^(8) Pa s is generally selected for thermoplastic forming(TPF),which takes advantage of the dramatic softening that MGs exhibit after being heated into the SLR.We further gave the TPF process window covering the range of processing temperature and time by utilizing the obtained viscosity data and timetemperature-transformation curves.The optimal time window avoiding property degradation was also determined,based on that there was no marked effect on the mechanical properties of MGs when crystallinity was below~5%.Our findings not only provide the accurate viscosity data in the SLR,but also determine the optimal process parameters for the TPF process. 展开更多
关键词 metallic glass VISCOSITY supercooled liquid thermoplastic forming fast scanning calorimetry
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Understanding vitrification kinetics through fast scanning calorimetry
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作者 Qi Cheng 《Science China(Physics,Mechanics & Astronomy)》 2025年第6期46-48,共3页
The phenomenon of vitrification,or glass transition,remains one of the most intriguing unsolved issues in condensed matter physics[1].Differential scanning calorimetry(DSC)has long been considered a valuable technique... The phenomenon of vitrification,or glass transition,remains one of the most intriguing unsolved issues in condensed matter physics[1].Differential scanning calorimetry(DSC)has long been considered a valuable technique for addressing this question[2].Since its commercialization in the 1960s,DSC has become a widely used tool in materials science for characterizing thermodynamic and kinetics properties[3],phase transitions[4],and enthalpy changes[5]in glasses.Traditional DSC features a time constant of approximately 1 s and scanning rate ranging from 0.1 to 300 K min^(-1).With the emergence of fast scanning calorimetry(FSC),this tool has evolved from a basic characterization method to an advanced and versatile technique for various aspects of glassy materials.The first generation of commercial FSC,utilizing a twin-chip sensor designed for the Mettler Toledo Flash 1 DSC[6,7],achieved a signal time constant below 1 ms,enabling high heating rate(qh)up to 40000 K s^(-1) and cooling rate(qc)of 10000 K s^(-1) within a temperature range of 173 to 793 K.The second generation,FDSC 2+,further increased these rates to 60000 K s^(-1) for heating and 40000 K s^(-1) for cooling,expanding the maximum temperature to 1273 K and facilitating the in-situ melting of various alloys[8]. 展开更多
关键词 enthalpy changes differential scanning calorimetry materials science VITRIFICATION fast scanning calorimetry glass transition condensed matter physics differential scanning calorimetry dsc characterizing thermodynamic kinetics properties phase transitions
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A fast scanning strategy based on trajectory shaping for atomic force microscopy
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作者 Yinan Wu Yingao Chang +1 位作者 Yongchun Fang Zhi Fan 《Nano Research》 SCIE EI CSCD 2022年第7期6438-6446,共9页
To improve the scanning speed of an atomic force microscopy(AFM),a smooth scanning pattern is elaborately devised via trajectory shaping in this paper,so as to achieve fast imaging without hardware modification.Specif... To improve the scanning speed of an atomic force microscopy(AFM),a smooth scanning pattern is elaborately devised via trajectory shaping in this paper,so as to achieve fast imaging without hardware modification.Specifically,in the proposed scanning method,the piezoelectric actuator tracks a well-designed smooth periodic signal in x-direction,and simultaneously tracks a step signal in y-direction.The advantage of the proposed method is that it does not require additional data reprocessing to construct the morphology of the sample surface,while significantly increasing the scanning bandwidth restricted by the raster scanning method.Particularly,to directly utilize the height data collected by scanning to produce the sample morphology,the forward process in the common raster scanning mode is retained in the proposed method,the tracking signal in the forward process is thus set to a ramp function in x-direction.In addition,to ensure the continuity and smoothness of the entire tracking signal in x-direction,a segment of a sine curve is uniquely determined as the backward tracking signal by position and acceleration constraints,so as to ensure that the forward and backward curves are continuous and acceleration-continuous at the intersection point.Moreover,the frequency spectrum analysis of the designed smooth signal is carried out to exhibit the depressed amplitudes of high-frequency components,which demonstrates that the proposed method is able to reduce the resonance in AFM high-speed scanning,so as to improve the capacity of rapidly generating high-quality images.Finally,convincing comparison experiments are implemented to verify the imaging performance of the designed scanning algorithm. 展开更多
关键词 atomic force microscopy fast scanning smooth signal trajectory shaping
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Battlefield dynamic scanning and staring imaging system based on fast steering mirror 被引量:4
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作者 CHANG Tianqing WANG Quandong +2 位作者 ZHANG Lei HAO Na DAI Wenjun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第1期37-56,共20页
This paper presents the design of an experimental battlefield dynamic scanning and staring imaging system based on a fast steering mirror(FSM), which is capable of real-time monitoring of hot targets and wide-area rec... This paper presents the design of an experimental battlefield dynamic scanning and staring imaging system based on a fast steering mirror(FSM), which is capable of real-time monitoring of hot targets and wide-area reconnaissance of hot regions. First,the working principle and working sequence of the FSM are briefly analyzed. The mathematical model of the FSM system is built by modeling its dynamic and electrical properties, and the rationality of the model is validated by means of model identification. Second,the influence of external sources of disturbance such as the carrier and moment on the control precision of the FSM is effectively suppressed by the jointly controlling of proportional integral(PI)and disturbance observer(DOB), thus realizing a high precision and strong robustness control of the FSM system. Then, this paper designs an experimental prototype and introduces a special optical structure to enable the infrared camera to share the FSM with the visible light camera. Finally, the influence of the velocity difference between the mirror of the FSM and the rotating platform on the imaging quality of the system is experimentally analyzed by using the image sharpness evaluation method based on point sharpness. A good dynamic scanning and staring imaging result is achieved when the velocity of these two components correspond. 展开更多
关键词 fast STEERING mirror (FSM) dynamic scanning and staring backscanning compensation DISTURBANCE OBSERVER (DOB) point sharpness.
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基于双差约束的大偏移距数据近地表速度建模方法
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作者 张凯 李壮 +2 位作者 李振春 杨浩田 郭林杰 《石油物探》 北大核心 2025年第5期864-874,共11页
高密度地震数据采集技术的应用导致传统初至波走时层析速度建模方法在走时求取精度、计算效率以及反演精度等方面,无法满足大偏移距数据的处理要求。为此,提出了一种基于双差约束的大偏移距数据近地表速度建模方法。为提高大偏移距初至... 高密度地震数据采集技术的应用导致传统初至波走时层析速度建模方法在走时求取精度、计算效率以及反演精度等方面,无法满足大偏移距数据的处理要求。为此,提出了一种基于双差约束的大偏移距数据近地表速度建模方法。为提高大偏移距初至走时计算精度,采用局部算子与全局快速扫描算法相结合的方法求解程函方程得到高精度的初至走时。为了更好地约束相邻射线之间的速度更新以及消除大偏移距走时计算误差,在迭代求解层析反演方程组的过程中引入双差走时约束以提高反演精度。模型数据测试以及实际地震数据测试结果验证了所提方法处理大偏移距数据的适用性和可行性。 展开更多
关键词 大偏移距数据 初至波 走时层析反演 双差约束 快速扫描法
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基于Agisoft PhotoScan的无人机影像快速拼接在新农村规划中的应用 被引量:11
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作者 李秀全 陈竹安 张立亭 《湖北农业科学》 2016年第3期743-745,共3页
以新农村建设规划中存在的问题为基础,提出了基于Agisoft Photo Scan无人机影像的快速拼接方法在新农村建设规划中的应用,给新农村建设规划测量带来了极大的便利,可满足新农村建设的需要。
关键词 新农村建设规划 Agisoft PHOTO scan 无人机 快速拼接
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快速扫描对SiC/SiC复合材料工业CT检测图像质量影响
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作者 蒋明繁 邓晓东 +4 位作者 史枭颖 陈子木 洪智亮 鲁亮 常建卫 《航空制造技术》 北大核心 2025年第16期32-42,共11页
SiC/SiC复合材料因其优异的高温性能和轻质特性,广泛应用于航空发动机高温部件制备。然而,材料制备过程中易产生气孔、分层等缺陷,影响材料性能,因此需要准确、高效的无损检测方法。大量研究结果表明,CT检测是SiC/SiC复合材料最有效的... SiC/SiC复合材料因其优异的高温性能和轻质特性,广泛应用于航空发动机高温部件制备。然而,材料制备过程中易产生气孔、分层等缺陷,影响材料性能,因此需要准确、高效的无损检测方法。大量研究结果表明,CT检测是SiC/SiC复合材料最有效的检测方法之一,但传统CT检测通常需要数小时,时间长、成本高,而快速扫描可在样品旋转时连续曝光,可显著缩短扫描时间。通过试验对比不同扫描模式下的图像分辨率、噪声分布及缺陷识别能力,本文提出了优化扫描参数的方法,在保证图像质量的同时提高检测效率。试验结果表明,快速扫描技术在空间分辨率无明显下降的情况下,可大幅提升扫描速度。虽然图像噪声随采样幅数减少而增加,但通过调整电流等参数,可有效降低噪声影响。本文提出了在图像分辨率、噪声及扫描时间之间取得平衡的策略,为SiC/SiC复合材料快速工业CT检测工程化应用提供重要参考。 展开更多
关键词 快速扫描 CT检测 SIC/SIC复合材料 采样幅数 扫描电流
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60℃条件下尼龙6的熔融和重结晶行为
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作者 张睿 于博士 +4 位作者 杜梦雪 Katalee Jariyavidyanont 徐董 Christoph Schick René Androsch 《高分子材料科学与工程》 北大核心 2025年第7期102-108,共7页
在工业生产尼龙6产品的过程中,常在玻璃化转变温度(T_(g)=60℃)进行退火,在后续加工过程中会伴随着重结晶过程的发生。文中通过快速差示扫描量热仪(FSC)表征在60℃退火结晶的尼龙6,观察其在升温速率10~20000 K/s范围内的重结晶行为。结... 在工业生产尼龙6产品的过程中,常在玻璃化转变温度(T_(g)=60℃)进行退火,在后续加工过程中会伴随着重结晶过程的发生。文中通过快速差示扫描量热仪(FSC)表征在60℃退火结晶的尼龙6,观察其在升温速率10~20000 K/s范围内的重结晶行为。结果显示,其初始晶体熔点为64℃,仅比退火温度高4 K,此时晶体完整度低。另外,当升温速率高于1000 K/s时候,冷结晶峰在升温曲线上消失。当升温速率为20000 K/s时,仅有1个吸热峰在升温曲线被观察到,说明重结晶在该升温速率下能被抑制。 展开更多
关键词 尼龙6 快速差示扫描量热仪 重结晶
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Application of fast differential scanning calorimetry in nonmetallic glasses
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作者 Xinyu Luo Yonghao Sun Weihua Wang 《Science China(Physics,Mechanics & Astronomy)》 2025年第6期3-15,共13页
Fast differential scanning calorimetry is an advanced thermal-analysis instrument.It can perform fast heating and fast cooling on matters with the maximum temperature of 1273 K,with scanning rates spanning five orders... Fast differential scanning calorimetry is an advanced thermal-analysis instrument.It can perform fast heating and fast cooling on matters with the maximum temperature of 1273 K,with scanning rates spanning five orders of magnitude and a maximum of many tens of thousands Kelvin per second.Thus,it is possible to vitrify a wide range of polymers,molecular liquids and alloys in-situ,enabling isothermal and non-isothermal testing for thermodynamic or kinetic investigations.In this work,the most recent results obtained with fast differential scanning calorimetry for non-metallic glasses are reviewed.The physics underlying the functions of the instrument is explained,along with the specializations of sample preparation,data correction,and result interpretation.The paper covers key findings in the field of non-metallic glass research,such as crystallization dynamics,liquidliquid transition and glass stability.The purpose of this work is to provide beginners with high-quality data by preparing samples on chips and adjusting for thermal lags,and to help experienced scientists to investigate novel perspectives on metallic glasses using the same methodology as non-metallic glasses. 展开更多
关键词 fast differential scanning calorimetry non-metallic glass thermal lag MELTING CRYSTALLIZATION
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Investigations of liquid-liquid transitions in metallic melts by fast differential scanning calorimetry
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作者 Qi Cheng Yonghao Sun Weihua Wang 《Science China(Physics,Mechanics & Astronomy)》 2025年第6期33-45,共13页
Liquid-liquid transition in metallic melts is an intriguing phenomenon often confused with liquid-liquid separation,oxidation or precipitation.Here,we employ a state-of-the-art ultrafast chip-based differential scanni... Liquid-liquid transition in metallic melts is an intriguing phenomenon often confused with liquid-liquid separation,oxidation or precipitation.Here,we employ a state-of-the-art ultrafast chip-based differential scanning calorimeter to investigate the thermal behavior of six metallic melts,ranging from unary to quinary systems,at temperatures above their liquidus.Calorimetric signals of liquid-liquid transition vary across systems:Sn melts showed no direct endothermic or exothermic events,though liquid-liquid transition influenced solidification and melting temperatures,while Yb-Zn melts exhibited an exothermic peak during cooling,indicating liquid-liquid transition.Thermal signals in other systems including Li,Pd-Ni-P,Yb-Mg-Zn-Cu and Au-Ag-Pd-Cu-Si,are primarily driven by compositional changes.Our in-situ analysis provides new insights into the structural and compositional evolution of metallic melts,offering significant implications for the design and processing of novel materials. 展开更多
关键词 metallic melts fast differential scanning calorimetry liquid-liquid transition MELT-QUENCHING CRYSTALLIZATION
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聚苯硫醚等温结晶过程的高速扫描量热研究
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作者 郑基源 云芳 +2 位作者 张晓辉 秦鹏祥 卫来 《伊犁师范大学学报(自然科学版)》 2025年第2期30-40,共11页
近年来,高速扫描量热技术因其较高的升降温速率,通常用于结构转变等过程的捕捉.本文利用高速扫描量热仪(FSC)对聚苯硫醚(PPS)进行了等温结晶动力学的研究.研究发现:(1)PPS中存在焓弛豫现象,随着等温时间的增加PPS样品的焓值逐渐增加,且... 近年来,高速扫描量热技术因其较高的升降温速率,通常用于结构转变等过程的捕捉.本文利用高速扫描量热仪(FSC)对聚苯硫醚(PPS)进行了等温结晶动力学的研究.研究发现:(1)PPS中存在焓弛豫现象,随着等温时间的增加PPS样品的焓值逐渐增加,且最终趋于稳定,聚合物链段逐渐转变为平衡态;(2)随着等温时间的增加,PPS样品在433K与443K温度下存在两种晶型的竞争生长,随着等温温度升高到463K时,两种晶型的竞争生长已经过渡为一种晶型的生长.本文通过高速扫描量热技术以较高的速率对PPS材料的结晶行为进行了探究,期望对后续PPS材料加工工艺提供参考和借鉴. 展开更多
关键词 高速扫描量热 聚苯硫醚 焓弛豫 等温结晶
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FAST漂移扫描观测:快速射电暴信号模拟与模拟样本
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作者 王远明 余文飞 +2 位作者 潘之辰 王培 李菂 《天文学进展》 CSCD 北大核心 2019年第4期477-490,共14页
快速射电暴(fast radio burst,FRB)是一种发生在毫秒时标的射电爆发现象。观测发现,它们很可能来自银河系外,对研究致密天体并合、星际介质、宇宙大尺度结构等有着重要意义。中国新近建成的500 m口径球面射电望远镜(Five-hundred-meter ... 快速射电暴(fast radio burst,FRB)是一种发生在毫秒时标的射电爆发现象。观测发现,它们很可能来自银河系外,对研究致密天体并合、星际介质、宇宙大尺度结构等有着重要意义。中国新近建成的500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical Telescope,FAST)是世界上最大的单天线射电望远镜,其多波束漂移扫描观测有望在快速射电暴观测方面作出贡献。针对FAST的漂移扫描观测模式,开展了多种参数和分布下的快速射电暴模拟,构建了下述快速射电暴的样本:一个是对快速射电暴在射电观测参数空间进行模拟获得的样本;一个是根据快速射电暴本身距离(红移)与色散之间可能存在的关系,进行物理参数空间模拟获得的样本。每个样本均有50000个模拟的快速射电暴信号,它们不仅可用来检验应用于FAST巡天扫描观测的快速射电暴搜寻算法的探测效率,还可以用来研究FAST漂移扫描观测和各类快速射电暴搜寻算法的选择效应,从而有可能从实际快速射电暴探测结果反推快速射电暴的内禀物理性质和分布。获得的快速射电暴样本对重复快速射电暴观测和数据分析具有借鉴意义。 展开更多
关键词 fast 漂移扫描巡天 模拟 快速射电暴
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基于奇异值分解正则化和快速迭代收缩阈值算法的无相位辐射源重构算法
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作者 邓垫君 李燕 《物理学报》 北大核心 2025年第8期274-282,共9页
本文提出了一种基于奇异值分解(SVD)正则化和快速迭代收缩阈值算法(FISTA)的单层无相位辐射源重构算法.该方法能够有效地识别集成电路中的电磁干扰源.首先,通过近场扫描获取电磁场数据,随后利用源重构方法(SRM)在其表面重建等效偶极子模... 本文提出了一种基于奇异值分解(SVD)正则化和快速迭代收缩阈值算法(FISTA)的单层无相位辐射源重构算法.该方法能够有效地识别集成电路中的电磁干扰源.首先,通过近场扫描获取电磁场数据,随后利用源重构方法(SRM)在其表面重建等效偶极子模型.引入SVD正则化项以提高算法的稳定性和抗噪声能力,FISTA技术则加速了算法的收敛速度.为了验证该方法的准确性和对高斯噪声的鲁棒性,进行了贴片天线仿真分析和芯片实验测试.结果表明,该算法在第35次迭代时达到稳定,重构结果与仿真结果的相对误差为2.3%,迭代时间仅为传统方法的61.7%,相对误差减少了52%. 展开更多
关键词 奇异值分解 快速迭代收缩阈值算法 近场扫描 辐射源重构
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FAST工程新型液压促动器研制及性能分析 被引量:3
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作者 刘兵 王超光 +3 位作者 张建 白志岩 楫骏 肖聚亮 《液压与气动》 北大核心 2015年第8期111-113,118,共4页
针对500 m口径球面射电望远镜(FAST)工程需求,介绍了一种自带动力源的液压促动器,阐述了其工作原理和集成化的结构,分析了该促动器在主动反射面系统中具体功能的实现过程。对其在正常工作状态下的换源和扫描跟踪性能进行了实验,结果表... 针对500 m口径球面射电望远镜(FAST)工程需求,介绍了一种自带动力源的液压促动器,阐述了其工作原理和集成化的结构,分析了该促动器在主动反射面系统中具体功能的实现过程。对其在正常工作状态下的换源和扫描跟踪性能进行了实验,结果表明液压促动器的动态性能和控制精度满足在FAST工程的要求,具有良好的实用性。 展开更多
关键词 fast 液压促动器 集成化结构 换源 扫描跟踪
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脑内多巴胺信号动态变化的检测方法及在成瘾研究中的应用 被引量:1
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作者 顾钧 谢小虎 +4 位作者 符丹 李龙辉 陈为升 刘惠芬 周文华 《生命的化学》 CAS 2024年第2期291-299,共9页
多巴胺是脑内重要的神经递质,中脑多巴胺系统在控制奖赏、动机、运动和情绪调节过程中起重要作用。脑内多巴胺功能紊乱与药物依赖、精神分裂症、抑郁症和帕金森氏病等神经精神障碍有关,动态测定脑内多巴胺变化对于了解多巴胺功能和揭示... 多巴胺是脑内重要的神经递质,中脑多巴胺系统在控制奖赏、动机、运动和情绪调节过程中起重要作用。脑内多巴胺功能紊乱与药物依赖、精神分裂症、抑郁症和帕金森氏病等神经精神障碍有关,动态测定脑内多巴胺变化对于了解多巴胺功能和揭示相关疾病病理机制具有重要意义。本文主要介绍了微透析、快速扫描循环伏安法和光纤光度法的基本原理和方法,并对比分析了这些技术在多巴胺动态检测应用中的优缺点。以药物成瘾研究为应用实例,利用微透析法发现伏隔核壳部是成瘾性药物产生奖赏效应的关键部位,快速扫描循环伏安法检测到与可卡因自身给药行为相关的三种多巴胺信号模式,而光纤光度法则揭示了酒精成瘾和复吸过程中伏隔核和中脑复侧被盖区多巴胺活动特征存在空间和时间上的多样性。这些发现为揭示药物成瘾的机制做出了重要贡献。 展开更多
关键词 多巴胺 成瘾 微透析 快速扫描循环伏安法 光纤光度法
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阵列式柔性薄膜传感器的快速扫描实现 被引量:1
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作者 刘丰铨 尹锡轩 +3 位作者 郭伟东 牛鑫蕊 东浩 胡正发 《传感器与微系统》 CSCD 北大核心 2024年第8期102-105,共4页
柔性薄膜传感器由于具有极高的柔韧性和可拓展性,可生产出不同大小的面积形状,通过阵列式排布,可以设计出大尺寸、多样化与数据实时特点的集成传感器模块。但对于大尺寸阵列式柔性薄膜的数据实时采集的方法仍存在挑战,本文基于STM32单... 柔性薄膜传感器由于具有极高的柔韧性和可拓展性,可生产出不同大小的面积形状,通过阵列式排布,可以设计出大尺寸、多样化与数据实时特点的集成传感器模块。但对于大尺寸阵列式柔性薄膜的数据实时采集的方法仍存在挑战,本文基于STM32单片机以及一块4×4(可拓展)的阵列式柔性薄膜,经STM32控制,实现阵列式快速扫描,实时快速地定位出信号来源并反馈出在该薄膜单元的压力变化值。 展开更多
关键词 柔性薄膜 阵列式 快速扫描 传感器 压力应变
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基于STM32的柔性传感器信号检测系统研究 被引量:1
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作者 杨焜宇 郭伟东 +2 位作者 尹锡轩 刘丰铨 胡正发 《现代信息科技》 2024年第12期178-182,187,共6页
针对柔性传感器的信号采集检测需求,基于STM32单片机和4×4阵列型柔性压力传感器,研究一种以单片机为核心单元、面向柔性传感器压力定位、压力变化、压力定量的实时数据采集检测系统。该检测系统采用单片机嵌入式程序结合快速行列... 针对柔性传感器的信号采集检测需求,基于STM32单片机和4×4阵列型柔性压力传感器,研究一种以单片机为核心单元、面向柔性传感器压力定位、压力变化、压力定量的实时数据采集检测系统。该检测系统采用单片机嵌入式程序结合快速行列扫描技术对采集的电信号数据进行分析、转换及分类显示,实现了精准的压力感知定位、分辨与测定,研究结果将会极大地推进融合计算机扫描技术和柔性阵列传感器新应用的推出。 展开更多
关键词 柔性压力传感器 快速扫描 STM32单片机 信号检测
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