期刊文献+
共找到76,864篇文章
< 1 2 250 >
每页显示 20 50 100
Modulated-ISRJ rejection using online dictionary learning for synthetic aperture radar imagery 被引量:1
1
作者 WEI Shaopeng ZHANG Lei +1 位作者 LU Jingyue LIU Hongwei 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期316-329,共14页
In electromagnetic countermeasures circumstances,synthetic aperture radar(SAR)imagery usually suffers from severe quality degradation from modulated interrupt sampling repeater jamming(MISRJ),which usually owes consid... In electromagnetic countermeasures circumstances,synthetic aperture radar(SAR)imagery usually suffers from severe quality degradation from modulated interrupt sampling repeater jamming(MISRJ),which usually owes considerable coherence with the SAR transmission waveform together with periodical modulation patterns.This paper develops an MISRJ suppression algorithm for SAR imagery with online dictionary learning.In the algorithm,the jamming modulation temporal properties are exploited with extracting and sorting MISRJ slices using fast-time autocorrelation.Online dictionary learning is followed to separate real signals from jamming slices.Under the learned representation,time-varying MISRJs are suppressed effectively.Both simulated and real-measured SAR data are also used to confirm advantages in suppressing time-varying MISRJs over traditional methods. 展开更多
关键词 synthetic aperture radar(SAR) modulated interrupt sampling jamming(MISRJ) online dictionary learning
下载PDF
Voltage-modulated polymer nanopore field-effect transistor for multi-sized nanoparticle detection
2
作者 Feng Zhou Lin Li Qiannan Xue 《Nanotechnology and Precision Engineering》 EI CAS CSCD 2024年第3期79-89,共11页
Solid-state nanopores offer a range of distinct advantages over biological nanopores,such as structural diversity and greater stability and durability;this makes them highly promising for high-resolution nanoparticle ... Solid-state nanopores offer a range of distinct advantages over biological nanopores,such as structural diversity and greater stability and durability;this makes them highly promising for high-resolution nanoparticle sensing.Biological nanopores can exhibit gating characteristics with stress-responsive switches and can demonstrate specificity toward particular molecules.Drawing inspiration from biological nanopores,this paper introduces a novel polymer nanopore with field-effect characteristics,leveraging a conductive polymer in its construction to showcase intriguing gating behavior.Notably,in this device,the polymer layer serves as the gate,enabling precise control over the source–drain current response inside and outside the pore by simply adjusting the gate voltage.This unique feature allows fine-tuning of the nanopore’s sensitivity to nanoparticles of varying sizes and facilitates its operation in multiple modes.Experimental results reveal that the developed polymer nanopore field-effect transistor demonstrates remarkable selectivity in detecting nanoparticles of various sizes under different applied voltages.The proposed single device demonstrates the exceptional ability to detect multiple types of nanoparticle,showcasing its immense potential for a wide range of applications in biological-particle analysis and medical diagnostics. 展开更多
关键词 Nanopipette Polymer nanopore Voltage modulation Nanoparticle detection
下载PDF
Preclinical Verification of Modulated Electro-Hyperthermia —Part I. In Vitro Research
3
作者 Andras Szasz 《International Journal of Clinical Medicine》 CAS 2024年第7期257-298,共42页
Modulated electro-hyperthermia (mEHT) targets tissue’s natural electric and thermal heterogeneities to heat the cancer cells selectively. The applied 13.56 MHz radiofrequency (RF) is a carrier of the low-frequency mo... Modulated electro-hyperthermia (mEHT) targets tissue’s natural electric and thermal heterogeneities to heat the cancer cells selectively. The applied 13.56 MHz radiofrequency (RF) is a carrier of the low-frequency modulation. The high-frequency part was chosen to select the malignant lesion using the specialties of the tumor: the higher conductivity and dielectric constant of the tumor than its host. The electric field selects the tumor, and the low-frequency amplitude modulation polarizes and excites the transmembrane proteins of the malignant cells. The dominant absorption of the energy by the microscopic clusters of the membrane rafts acts like nanoparticle heating. Exciting the membrane produces various apoptotic signals. The processes were modeled using silico and phantom experiments, which proved the concept. The preclinical verification was made in vitro and in vivo, and in the end, clinical proofs validated the method. Our objective is to follow all the development steps from the laboratory to the clinics in a trilogy of articles. This present is the first part, which deals with in silico, phantom, and in vitro research. 展开更多
关键词 modulated Electro-Hyperthermia mEHT In Silico Calculations Phantom Measurement In Vitro Experiments Thermal Effects Nonthermal Processes Apoptosis
下载PDF
Age of Information for Short-Packet Covert Communication with Time Modulated Retrodirective Array
4
作者 Ma Yue Ma Ruiqian +4 位作者 Lin Zhi Yang Weiwei Cai Yueming Miao Chen Wu Wen 《China Communications》 SCIE CSCD 2024年第4期23-37,共15页
In this paper,the covert age of information(CAoI),which characterizes the timeliness and covertness performance of communication,is first investigated in the short-packet covert communication with time modulated retro... In this paper,the covert age of information(CAoI),which characterizes the timeliness and covertness performance of communication,is first investigated in the short-packet covert communication with time modulated retrodirective array(TMRDA).Specifically,the TMRDA is designed to maximize the antenna gain in the target direction while the side lobe is sufficiently suppressed.On this basis,the covertness constraint and CAoI are derived in closed form.To facilitate the covert transmission design,the transmit power and block-length are jointly optimized to minimize the CAoI,which demonstrates the trade-off between covertness and timelessness.Our results illustrate that there exists an optimal block-length that yields the minimum CAoI,and the presented optimization results can achieve enhanced performance compared with the fixed block-length case.Additionally,we observe that smaller beam pointing error at Bob leads to improvements in CAoI. 展开更多
关键词 age of information covert communication retrodirective array time modulation
下载PDF
Topological Structure-Modulated Collagen Carbon as Two-in-One Energy Storage Configuration toward Ultrahigh Power and Energy Density
5
作者 Li Yuan Wenlong Cai +4 位作者 Yunhong Wei Yiran Pu Can Liu Yun Zhang Hao Wu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第2期18-29,共12页
Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the susta... Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles). 展开更多
关键词 collagen carbon energy storage device theoretical calculations topological structure modulation ultrahigh power and energy density
下载PDF
Calcium-sensitive protein MLC1 as a possible modulator of the astrocyte functional state
6
作者 Elena Ambrosini Angela Lanciotti Maria Stefania Brignone 《Neural Regeneration Research》 SCIE CAS 2025年第7期2008-2010,共3页
Astrocytes,the main population of glial cells in the central nervous system(CNS),exert essential tasks for the control of brain tissue homeostasis,supporting neuron and other glial cell activity from the developmental... Astrocytes,the main population of glial cells in the central nervous system(CNS),exert essential tasks for the control of brain tissue homeostasis,supporting neuron and other glial cell activity from the developmental stage to adult life.To maintain the optimal functionality of the brain,astroglial cells are particularly committed to reacting to every change in tissue homeostatic conditions,from mild modifications of the physiological environment,a process called astrocyte activation,to the more severe alterations occurring in pathological situations causing astrocyte reactivity or reactive astrogliosis(Escartin et al.,2021).During these reactive states,astrocytes mount an active,progressive response encompassing morphological,molecular,and interactional remodeling,leading to the acquisition of new functions and the loss of others,whose intensity,duration,and reversibility are dependent on the nature of the stimulus and regulated in a context-specific manner. 展开更多
关键词 alterations modulATOR MAINTAIN
下载PDF
Neuropeptide cholecystokinin:a key neuromodulator for hippocampal functions
7
作者 Fengwen Huang Stephen Temitayo Bello 《Neural Regeneration Research》 SCIE CAS 2025年第7期1991-1992,共2页
Spatial memory is crucial for survival within external surroundings and wild environments.The hippocampus,a critical hub for spatial learning and memory formation,has received extensive investigations on how neuromodu... Spatial memory is crucial for survival within external surroundings and wild environments.The hippocampus,a critical hub for spatial learning and memory formation,has received extensive investigations on how neuromodulators shape its functions(Teixeira et al.,2018;Zhang et al.,2024).However,the landscape of neuromodulations in the hippocampal system remains poorly understood because most studies focus on classical monoamine neuromodulators,such as acetylcholine,serotonin,dopamine,and noradrenaline.The neuropeptides,comprising the most abundant neuromodulators in the central nervous system,play a pivotal role in neural information processing in the hippocampal system.Cholecystokinin(CCK),one of the most abundant neuropeptides,has been implicated in regulating various physiological and neurobiological statuses(Chen et al.,2019).CCK-A receptor(CCK-AR)and CCK-B receptors(CCK-BR)are two key receptors mediating the biological functions of CCK,both of which belong to class-A sevenfold transmembrane G protein-coupled receptors(Nishimura et al.,2015).CCK-AR preferentially reacts to sulfated CCK,whereas CCK-BR binds both CCK and gastrin with similar affinities(Ding et al.,2022).The expression patterns of CCK-AR and CCK-BR are distinct,implying that CCK has various functions in target regions.For instance,CCK-AR is widely expressed in the GI and brain subregions and is hence implicated in the control of digestive function and satiety regulation.Conversely,CCK-BR is abundantly and widely distributed in the central nervous system,which majorly regulates anxiety,learning,and memory(Ding et al.,2022).However,the roles of endogenous CCK and CCK receptors in regulating hippocampal function at electrophysiological and behavioral levels have received less attention. 展开更多
关键词 abundant FUNCTIONS modulATOR
下载PDF
Crystallization Modulation and Holistic Passivation Enables Efficient Two‑Terminal Perovskite/CuIn(Ga)Se_(2)Tandem Solar Cells
8
作者 Cong Geng Kuanxiang Zhang +7 位作者 Changhua Wang Chung Hsien Wu Jiwen Jiang Fei Long Liyuan Han Qifeng Han Yi‑Bing Cheng Yong Peng 《Nano-Micro Letters》 SCIE EI CAS 2025年第1期205-215,共11页
Two-terminal(2-T)perovskite(PVK)/CuIn(Ga)Se_(2)(CIGS)tandem solar cells(TSCs)have been considered as an ideal tandem cell because of their best bandgap matching regarding to Shockley–Queisser(S–Q)limits.However,the ... Two-terminal(2-T)perovskite(PVK)/CuIn(Ga)Se_(2)(CIGS)tandem solar cells(TSCs)have been considered as an ideal tandem cell because of their best bandgap matching regarding to Shockley–Queisser(S–Q)limits.However,the nature of the irregular rough morphology of commercial CIGS prevents people from improving tandem device performances.In this paper,D-homoserine lactone hydrochloride is proven to improve coverage of PVK materials on irregular rough CIGS surfaces and also passivate bulk defects by modulating the growth of PVK crystals.In addition,the minority carriers near the PVK/C60 interface and the incompletely passivated trap states caused interface recombination.A surface reconstruction with 2-thiopheneethylammonium iodide and N,N-dimethylformamide assisted passivates the defect sites located at the surface and grain boundaries.Meanwhile,LiF is used to create this field effect,repelling hole carriers away from the PVK and C60 interface and thus reducing recombination.As a result,a 2-T PVK/CIGS tandem yielded a power conversion efficiency of 24.6%(0.16 cm^(2)),one of the highest results for 2-T PVK/CIGS TSCs to our knowledge.This validation underscores the potential of our methodology in achieving superior performance in PVK/CIGS tandem solar cells. 展开更多
关键词 PVK/CIGS TSCs Irregular rough surfaces modulating the growth PVK/C60 interface recombination
下载PDF
On approximating multifractal traffic burstiness with Markov modulated Poisson processes 被引量:1
9
作者 纪其进 《Journal of Southeast University(English Edition)》 EI CAS 2004年第4期436-441,共6页
We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correl... We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correlation in moderate time scales while being analytically tractable. Important statistics of traffic burstiness are described and a customized moment-based fitting procedure of MMPP to traffic traces is presented. Our methodology of doing this is to examine whether the MMPP can be used to predict the performance of a queue to which MMPP sample paths and measured traffic traces are fed for comparison respectively, in addition to the goodness-of-fit test of MMPP. Numerical results and simulations show that the fitted MMPP can approximate multifractal traffic quite well, i.e. accurately predict the queueing performance. 展开更多
关键词 multifractal traffic Markov modulated Poisson processes queueing delay packet loss rate
下载PDF
应用调制差示扫描量热计(Modulated-DSC)分离非晶态合金的玻璃化转变 被引量:2
10
作者 吕昭平 李毅 卢柯 《金属学报》 SCIE EI CAS CSCD 北大核心 1999年第1期73-77,共5页
应用调制差示扫描量热计对非晶态合金La55Al25Ni10Cu10,Mg65Zn35,Nd60Fe30Al10以及Zr30Y30Al15Ni25的玻璃化转变过程进行了研究.在Mg65Zn35和Nd60Fe30Al10... 应用调制差示扫描量热计对非晶态合金La55Al25Ni10Cu10,Mg65Zn35,Nd60Fe30Al10以及Zr30Y30Al15Ni25的玻璃化转变过程进行了研究.在Mg65Zn35和Nd60Fe30Al10合金中观察到了玻璃化转变;在Mg65Zn35,Nd60Fe30Al10以及Zr30Y30Al15Ni25中甚至观察到两个玻璃化转变过程.由于能够清楚地观察到玻璃化转变过程,因此可以得到更加精确的约化玻璃化转变温度(玻璃化转变温度/熔点). 展开更多
关键词 差示扫描量热计 非晶态合金 玻璃化转变 DSC
下载PDF
Markov-modulated风险模型破产前最大盈余额与破产赤字的联合分布 被引量:2
11
作者 董继国 刘国欣 《高校应用数学学报(A辑)》 CSCD 北大核心 2010年第1期9-12,共4页
应用逐段决定马尔可夫过程理论及补充变量技巧,使Markov-modulated风险过程成为齐次强马尔可夫过程,然后利用强马氏性及首达时间分布给出了其破产前最大盈余额与破产赤字的联合分布.
关键词 Markov-modulated风险模型 逐段决定马尔可夫过程 补充变量
下载PDF
Cosine-modulated window function-based staggered-grid finite-difference forward modeling 被引量:5
12
作者 王建 孟小红 +2 位作者 刘洪 郑婉秋 贵生 《Applied Geophysics》 SCIE CSCD 2017年第1期115-124,191,共11页
The numerical dispersion and computational cost are high for conventional Taylor series expansion staggered-grid finite-difference forward modeling owing to the high frequency of the wavelets and the large grid interv... The numerical dispersion and computational cost are high for conventional Taylor series expansion staggered-grid finite-difference forward modeling owing to the high frequency of the wavelets and the large grid intervals. In this study, the cosine-modulated binomial window function (CMBWF)-based staggered-grid finite-difference method is proposed. Two new parameters, the modulated time and modulated range are used in the new window function and by adjusting these two parameters we obtain different characteristics of the main and side lobes of the amplitude response. Numerical dispersion analysis and elastic wavefield forward modeling suggests that the CMBWF method is more precise and less computationally costly than the conventional Taylor series expansion staggered-grid finite-difference method. 展开更多
关键词 Elastic wave staggered grid window function cosine modulate
下载PDF
Markov-Modulated风险模型的极大值、极小值及零点数的联合分布
13
作者 董继国 刘国欣 《应用概率统计》 CSCD 北大核心 2011年第5期473-480,共8页
本文基于保险公司在首次破产后仍能继续运转的情形,讨论并得到了Markov-modulated风险模型中关于末离零点前盈余过程极大值、极小值及零点数的联合分布.
关键词 Markov-modulated风险模型 逐段决定马尔可夫过程 补充变量
下载PDF
Markov-modulated风险模型中盈余过程零点数的分布
14
作者 董继国 刘国欣 《高校应用数学学报(A辑)》 CSCD 北大核心 2008年第3期282-286,共5页
基于保险公司在首次破产后仍能继续运转的情形,讨论并得到了Markov- modulated风险模型中盈余过程零点数的分布.
关键词 Markov-modulated风险模型 逐段决定马尔可夫过程 补充变量
下载PDF
Surface Modification With Zinc and Zn-Ni Alloy Compositionally Modulated Multilayer Coatings 被引量:15
15
作者 FEI Jing-yin LIANG Guo-zheng XIN Wen-li WANG Wei-kang 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2006年第4期61-67,共7页
Zinc and Zn-Ni alloy compositionally modulated multilayer (CMM) coatings were electrodeposited on to a steel substrate by the successive deposition of zinc and Zn-Ni alloy sublayers from dual baths. The coated sampl... Zinc and Zn-Ni alloy compositionally modulated multilayer (CMM) coatings were electrodeposited on to a steel substrate by the successive deposition of zinc and Zn-Ni alloy sublayers from dual baths. The coated samples were evaluated in terms of the surface appearance, surface and cross-sectional morphologies, as well as corrosion resistance. The microstructural characteristics that were examined using the field emission gun scanning electron microscopy (FEGSEM) confirmed the layered structure, grain refinement of the zinc and Zn-Ni alloy CMM coatings, and revealed the existence of microcracks caused by the internal stress in the thick Zn-Ni alloy sublayers. The corrosion resistance that was evaluated by means of the salt spray test shows that the zinc and Zn-Ni alloy CMM coatings were more corrosion-resistant than the monolithic coatings of zinc or Zn-Ni alloy of the same thickness. The possible reasons for the better protective performance of Zn-Ni/Zn CMM coatings were given on the basis of the analysis on the micrographic features of zinc and Zn-Ni alloy CMM eoatings after the corrosion test. A probable corrosion mechanism of zinc and Zn-Ni alloy CMM coatings was also proposed. 展开更多
关键词 ELECTRODEPOSITION compositionally modulated multilayer coating Zn-Ni alloy corrosion resistance
下载PDF
Simultaneous modulated accelerated radiation therapy for esophageal cancer:A feasibility study 被引量:12
16
作者 Wu-Zhe Zhang Jian-Zhou Chen +6 位作者 De-Rui Li Zhi-Jian Chen Hong Guo Ting-Ting Zhuang Dong-Sheng Li Ming-Zhen Zhou Chuang-Zhen Chen 《World Journal of Gastroenterology》 SCIE CAS 2014年第38期13973-13980,共8页
AIM: To establish the feasibility of simultaneous modulated accelerated radiation therapy (SMART) in esophageal cancer (EC).
关键词 Simultaneous modulated accelerated radiation therapy Three-dimensional conformal radiotherapy Intensity-modulated radiation therapy Esophageal cancer FEASIBILITY
下载PDF
Dosimetry Comparison between Volumetric Modulated Arc Therapy with RapidArc and Fixed Field Dynamic IMRT for Local-Regionally Advanced Nasopharyngeal Carcinoma 被引量:7
17
作者 Bao-min Zheng Xiao-xia Dong +3 位作者 Hao Wu You-jia Duan Shu-kui Han Yan Sun 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2011年第4期259-264,共6页
Objective: A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC). Methods: The CT scan data sets of 20 p... Objective: A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC). Methods: The CT scan data sets of 20 patients of locally advanced NPC were selected randomly. The plans were managed using volumetric modulated arc with RapidArc and fixed nine-field coplanar dynamic intensity-modulated radiotherapy (IMRT) for these patients. The dosimetry of the planning target volumes (PTV), the organs at risk (OARs) and the healthy tissue were evaluated. The dose prescription was set to 70 Gy to the primary tumor and 60 Gy to the clinical target volumes (CTV) in 33 fractions. Each fraction applied daily, five fractions per week. The monitor unit (MU) values and the delivery time were scored to evaluate the expected treatment efficiency. Results: Both techniques had reached clinical treatment’s requirement. The mean dose (Dmean), maximum dose (Dmax) and minimum dose (Dmin) in RapidArc and fixed field IMRT for PTV were 68.4±0.6 Gy, 74.8±0.9 Gy and 56.8±1.1 Gy; and 67.6±0.6 Gy, 73.8±0.4 Gy and 57.5±0.6 Gy (P<0.05), respectively. Homogeneity index was 78.85±1.29 in RapidArc and 80.34±0.54 (P<0.05) in IMRT. The conformity index (CI: 95%) was 0.78±0.01 for both techniques (P>0.05). Compared to IMRT, RapidArc allowed a reduction of Dmean to the brain stem, mandible and optic nerves of 14.1% (P<0.05), 5.6% (P<0.05) and 12.2% (P<0.05), respectively. For the healthy tissue and the whole absorbed dose, Dmean of RapidArc was reduced by 3.6% (P<0.05), and 3.7% (P<0.05), respectively. The Dmean to the parotids, the spinal cord and the lens had no statistical difference among them. The mean MU values of RapidArc and IMRT were 550 and 1,379. The mean treatment time of RapidArc and IMRT was 165 s and 447 s. Compared to IMRT, the delivery time and the MU values of RapidArc were reduced by 63% and 60%, respectively. Conclusion: For locally advanced NPC, both RapidArc and IMRT reached the clinic requirement. The target volume coverage was similar for the different techniques. The RapidArc technique showed some improvements in OARs and other tissue sparing while using reduced MUs and delivery time. 展开更多
关键词 Volumetric modulated arc therapy Intensity-modulated radiotherapy DOSIMETRY Target volume Nasopharyngeal carcinoma
下载PDF
Research on sinusoid modulated pulse MIG welding methodology 被引量:5
18
作者 魏仲华 陈小峰 薛家祥 《China Welding》 EI CAS 2011年第4期75-80,共6页
This article proposed a new methodology and the principle of sinusoid modulated pulse MIG welding, and systematically established the universal mathematical model of computation of the parameters of the sinusoid modul... This article proposed a new methodology and the principle of sinusoid modulated pulse MIG welding, and systematically established the universal mathematical model of computation of the parameters of the sinusoid modulation pulse, achieving that the welding energy input can be effectively controlled and precisely regulated, the transition of pulse change is smooth and the welding process is stable and reliable. With the characteristics of sinusoidal waveform, such as infinite derivative continuity, eternal periodicity and limited control parameters, this article established the theoretical foundation for choiceness, unification and optimization of the parameters during the new sinusoid modulated pulse MIG welding. Bead-on-plate overlay welding is carried out on the pure aluminum sheet test sample for the test. The result indicated that during the welding process, the real-time current waveform is stable and clear; both the corresponding voltage and the instant welding energy waveform are very stable; the repeatability of the U-I graph plotted is high; its family of lines is clear, neat, and its distribution is concentrated showing that the welding process is stable and the neat and high quality ripple weld seam may be produced. 展开更多
关键词 sinusoid modulation sinusoid modulated pulse MIG welding parameter tuning
下载PDF
On Multi-Timescale Variability of Temperature in China in Modulated Annual Cycle Reference Frame 被引量:16
19
作者 钱诚 Zhaohua WU +1 位作者 符淙斌 周天军 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第5期1169-1182,共14页
The traditional anomaly (TA) reference frame and its corresponding anomaly for a given data span changes with the extension of data length. In this study, the modulated annual cycle (MAC), instead of the widely us... The traditional anomaly (TA) reference frame and its corresponding anomaly for a given data span changes with the extension of data length. In this study, the modulated annual cycle (MAC), instead of the widely used climatological mean annual cycle, is used as an alternative reference frame for computing climate anomalies to study the multi-timescale variability of surface air temperature (SAT) in China based on homogenized daily data from 1952 to 2004. The Ensemble Empirical Mode Decomposition (EEMD) method is used to separate daily SAT into a high frequency component, a MAC component, an interannual component, and a decadal-to-trend component. The results show that the EEMD method can reflect historical events reasonably well, indicating its adaptive and temporally local characteristics. It is shown that MAC is a temporally local reference frame and will not be altered over a particular time span by an exten-sion of data length, thereby making it easier for physical interpretation. In the MAC reference frame, the low frequency component is found more suitable for studying the interannual to longer timescale variability (ILV) than a 13-month window running mean, which does not exclude the annual cycle. It is also better than other traditional versions (annual or summer or winter mean) of ILV, which contains a portion of the annual cycle. The analysis reveals that the variability of the annual cycle could be as large as the magnitude of interannual variability. The possible physical causes of different timescale variability of SAT in China are further discussed. 展开更多
关键词 modulated annual cycle the Ensemble Empirical Mode Decomposition climate anomaly climate normal variability of surface air temperature in China
下载PDF
Thickness-modulated in-plane Bi2O2Se homojunctions for ultrafast high-performance photodetectors 被引量:3
20
作者 Cheng-Yun Hong Gang-Feng Huang +2 位作者 Wen-Wen Yao Jia-Jun Deng Xiao-Long Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第12期363-369,共7页
Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored ... Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored in the photodetecting area. Considering the fact that the electrical properties such as carrier mobility, work function, and energy band structure of Bi2O2Se are thickness-dependent, the in-plane Bi2O2Se homojunctions consisting of layers with different thicknesses are successfully synthesized by the chemical vapor deposition(CVD) method across the terraces on the mica substrates,where terraces are created in the mica surface layer peeling off process. In this way, effective internal electrical fields are built up along the Bi2O2Se homojunctions, exhibiting diode-like rectification behavior with an on/off ratio of 102, what is more, thus obtained photodetectors possess highly sensitive and ultrafast features, with a maximum photoresponsivity of 2.5 A/W and a lifetime of 4.8 μs. Comparing with the Bi2O2Se uniform thin films, the photo-electric conversion efficiency is greatly improved for the in-plane homojunctions. 展开更多
关键词 Bi2O2Se in-plane homojunction thickness modulation PHOTODETECTORS
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部