期刊文献+
共找到9,644篇文章
< 1 2 250 >
每页显示 20 50 100
Nonlinear time-reversal interferometry with arbitrary quadratic collective-spin interaction
1
作者 胡知遥 李其贤 +3 位作者 张轩晨 张贺宾 黄龙刚 刘永椿 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第8期63-70,共8页
Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science.Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain bas... Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science.Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain based on the spin squeezing generated by arbitrary quadratic collective-spin interaction,which could be described by the Lipkin–Meshkov–Glick(LMG)model.We optimize the squeezing process,encoding process,and anti-squeezing process,finding that the two particular cases of the LMG model,one-axis twisting and two-axis twisting outperform in robustness and precision,respectively.Moreover,we propose a Floquet driving method to realize equivalent time reverse in the atomic system,which leads to high performance in precision,robustness,and operability.Our study sets a benchmark for achieving high precision and high robustness in atomic nonlinear interferometry. 展开更多
关键词 time-reversal interferometry spin squeezing quantum metrology
下载PDF
基于Focal Loss改进LightGBM的供水管网毛刺数据检测
2
作者 薛浩 马静 郭小宇 《计算机与现代化》 2024年第9期74-81,90,共9页
针对数据不平衡导致的管网毛刺数据检测召回率偏低问题,提出一种Focal Loss改进LightGBM的管网毛刺数据检测方法。首先,结合管网毛刺数据的特点,针对性构造邻域相关特征。其次,将Focal Loss函数引入LightGBM,提高模型对难以检测的毛刺... 针对数据不平衡导致的管网毛刺数据检测召回率偏低问题,提出一种Focal Loss改进LightGBM的管网毛刺数据检测方法。首先,结合管网毛刺数据的特点,针对性构造邻域相关特征。其次,将Focal Loss函数引入LightGBM,提高模型对难以检测的毛刺样本的权重,并对Focal Loss不同的参数取值进行实验,以平衡精确率与召回率。最后,选择不同参数的Focal Loss进行模型融合,进一步提升模型对不平衡毛刺数据的检测性能。在某市供水管网的真实数据上进行实验,结果表明,对比基于交叉熵损失函数的单一模型,本文提出的Focal Loss改进后的融合模型在毛刺数据上召回率和F1值的提升幅度达33.3和18个百分点,但毛刺数据的精确率还有待进一步提升。本文所提方法从损失函数入手,动态调整难易样本的权重,有效地提升了不平衡数据下的毛刺数据的检测性能。 展开更多
关键词 异常检测 focal Loss LightGBM 不平衡数据 毛刺数据
下载PDF
Research on Post-classical Narrative Focalization in The Love Wife
3
作者 郭丽莉 《海外英语》 2013年第16期171-172,共2页
The Love Wife is considered to be a breakthrough of Gish Jen either in theme and narrative techniques. While, as the critical distinguished narrative technique from the perspective of Post-classical Narratology, the i... The Love Wife is considered to be a breakthrough of Gish Jen either in theme and narrative techniques. While, as the critical distinguished narrative technique from the perspective of Post-classical Narratology, the infinitive internal focalization will be analyzed in this paper so as to investigate the five protagonists'search for their own identity and eagerness to achieve the acknowledge both from their family and the whole society. Furthermore, the author's own view in breaking up the barrier and discrimination around the world is also well-illustrated. 展开更多
关键词 INFINITIVE internal focalization IDENTITY
下载PDF
Character and Focalization in Alice Munro's Runaway
4
作者 严璐 《海外英语》 2016年第16期158-160,166,共4页
Runaway is a traditional motif in women's writing. But Alice Munro uses this motif differently. In her short story, Runaway, Munro explores the psychological transition of the female protagonist, Carla, and invest... Runaway is a traditional motif in women's writing. But Alice Munro uses this motif differently. In her short story, Runaway, Munro explores the psychological transition of the female protagonist, Carla, and investigates the intricate issue of women's liberation and social reality. This essay discusses how Munro manipulates the focus of narration in order to reveal the mental struggles experienced by showing a complicated runaway experience by a rural Canadian house-wife living an ordinary life. 展开更多
关键词 Munro focalization RUNAWAY CHARACTERS
下载PDF
Seeing time-reversal transmission characteristics through kinetic anti-ferromagnetic Ising chain
5
作者 Chen Ying-Ming Wang Bing-Zhong 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第2期419-424,共6页
As an example of our new approach to complex near-field (NF) scattering of electromagnetic waves, the timereversal (TR) transmission process on an NF current-element array is mapped to the statistical process on a... As an example of our new approach to complex near-field (NF) scattering of electromagnetic waves, the timereversal (TR) transmission process on an NF current-element array is mapped to the statistical process on a kinetic Ising transmission chain. Equilibrium statistical mechanics and non-equilibrium Monte Carlo (MC) dynamics help us to find signal jamming, aging, annihilating, creating, and TR symmetry breaking on the chain with inevitable background noises; and these results are general in NF systems where complex electromagnetic scattering arises. 展开更多
关键词 time-reversal near-field scattering symmetry breaking temporal focusing
下载PDF
The focusing performance with a horizontal time-reversal array at different depths in shallow water
6
作者 张同伟 杨坤德 马远良 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第12期347-355,共9页
The performance of time-reversal focusing with a horizontal line array at different depths is investigated by normal mode modeling and computer simulation. It is observed that the focusing performance of a bottom-moun... The performance of time-reversal focusing with a horizontal line array at different depths is investigated by normal mode modeling and computer simulation. It is observed that the focusing performance of a bottom-mounted horizontal time-reversal array is much better than that of a horizontal time-reversal array at other depths in shallow water. The normal mode modeling is used to explain this result. The absolute values of the modes at different depths are compared. It is shown that the number of modes whose absolute values close to zero is smaller at the bottom than that at other depths. It means that the horizontal time-reversal array deployed at the bottom can sample more modes, obtain more information of the probe source and achieve better focusing performance. The numerical simulations of time-reversal focusing performance under various conditions, such as different sound speed profiles, and different bottom parameters, lead to similar results. 展开更多
关键词 time-reversal horizontal line array array depth
下载PDF
A novel power-combination method using a time-reversal pulse-compression technique
7
作者 陆希成 田锦 +2 位作者 张荣威 汪海波 邱扬 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期283-288,共6页
The electromagnetic time-reversal(TR)technique has the characteristics of spatiotemporal focusing in a time-reversal cavity(TRC),which can be used for pulse compression,thus forming an electromagnetic pulse with high ... The electromagnetic time-reversal(TR)technique has the characteristics of spatiotemporal focusing in a time-reversal cavity(TRC),which can be used for pulse compression,thus forming an electromagnetic pulse with high peak power.A time-reversed pulse-compression method in a single channel has high pulse compression gain.However,single channel pulse compression can only generate limited gain.This paper proposes a novel TR power-combination method in a multichannel TRC to obtain higher peak power based on TR pulse-compression theory.First,the TR power-combination model is given,and the crosstalk properties of the associated channel and the influence of the reversal performance are studied.Then,the power-combination performances for the TR pulse compression,such as combined signal to noise ratio(SNR)and combined compression gain,are analyzed by numerical simulation and experimental methods.The results show that the proposed method has obvious advantages over pulse-compression methods using a single channel cavity,and is more convenient for power combination. 展开更多
关键词 time reversal time-reversal cavity power combination pulse compression
下载PDF
Focalizations and Their Functions in Heart of Darkness
8
作者 Dong Xiaohua (Foreign Languages Department, Northwest Normal University, Lanzhou, 730070, China) 《兰州大学学报(社会科学版)》 CSSCI 北大核心 2000年第S1期109-113,共5页
As an important technique involved in the novel writing,the focalization is studied in detail in Narratology.The paper is an attempt to analyze the arrangement of focalizations and their functions in Heart of Dartness... As an important technique involved in the novel writing,the focalization is studied in detail in Narratology.The paper is an attempt to analyze the arrangement of focalizations and their functions in Heart of Dartness according to Narratology. 展开更多
关键词 focalizations narratology functions
下载PDF
The focalization in Winesburg, Ohio
9
作者 YIN Xue-yan 《Sino-US English Teaching》 2009年第11期55-59,共5页
Winesburg, Ohio is Sherwood Anderson's masterpiece. Adopting the classical theory of narratology, this paper intends to provide a detailed analysis on the zero focalization, writer's experiment with the shift of foc... Winesburg, Ohio is Sherwood Anderson's masterpiece. Adopting the classical theory of narratology, this paper intends to provide a detailed analysis on the zero focalization, writer's experiment with the shift of focalization, the transgression of focalization and their expressive effects in the book. The author aims at presenting an illustration to the focalization experiment in Winesburg, Ohio, one of the early modern fictions. 展开更多
关键词 zero focalization shift of focalization modern fiction
下载PDF
正常小鼠血清通过抑制focal adhesion信号通路减轻小鼠放射性肺炎
10
作者 苑通 郭玉莹 +1 位作者 张俊伶 樊赛军 《南方医科大学学报》 CAS CSCD 北大核心 2024年第5期801-809,共9页
目的探讨正常小鼠血清(NMS)对放射性肺炎的治疗作用及可能机制。方法建立胸腔照射诱导的放射性肺炎模型,将小鼠分为对照组、静脉注射血清组、照射组和照射后静脉注射血清组。注射血清组小鼠在照射后立即静脉注射正常小鼠血清100μL,对... 目的探讨正常小鼠血清(NMS)对放射性肺炎的治疗作用及可能机制。方法建立胸腔照射诱导的放射性肺炎模型,将小鼠分为对照组、静脉注射血清组、照射组和照射后静脉注射血清组。注射血清组小鼠在照射后立即静脉注射正常小鼠血清100μL,对照组小鼠注射100μL生理盐水,隔天注射1次,共注射8次。照射后15 d取材,HE染色检测肺组织形态学变化,ELISA检测小鼠肺组织和血清中炎症因子肿瘤坏死因子-α(TNF-α)、转化生长因子-β(TGF-β)、白细胞介素-1α(IL-1α)、白细胞介素-6(IL-6)水平;流式细胞术检测肺组织内淋巴细胞比例变化。外泌体miRNA高通量测序探索处理后小鼠的信号通路变化,qRT-PCR检测免疫相关基因的表达水平,使用Western blotting检测黏着斑通路talin-1、tensin 2、FAK、vinculin、α-actinin和paxillin蛋白的表达。结果与照射组相比,照射后注射血清组小鼠肺脏器系数、血清及肺组织上清液中炎症因子TNF-α、TGF-β、IL-1α、IL-6水平显著降低(P<0.05),CD45^(+)、CD4^(+)、T_(reg)淋巴细胞在小鼠肺组织中的浸润程度显著下降(P<0.05);肺中Egfr和Pik3cd的mRNA和蛋白表达水平显著下调,talin-1、tensin 2、FAK、vinculin、α-actinin和paxillin蛋白的表达水平也显著降低(P<0.05)。结论正常小鼠血清通过抑制focal adhesion信号通路关键蛋白的表达减轻电离辐射诱发的小鼠放射性肺炎。 展开更多
关键词 正常小鼠血清 放射性肺炎 外泌体 粘着斑途径
下载PDF
Narrative Focalization of William Faulkner's Barn Burning
11
作者 韩新宇 《海外英语》 2019年第6期202-206,共5页
Barn Burning is a short story written by William Faulkner, which first appeared in 1939 and has since been widely read.The story guides readers to observe the world through a 10-year-old boy, Sarty's point of view... Barn Burning is a short story written by William Faulkner, which first appeared in 1939 and has since been widely read.The story guides readers to observe the world through a 10-year-old boy, Sarty's point of view, at the same time, the continual intervening of omniscient narrator breaks through the restrictions of Sarty's subjective point of view. Faulkner's use of multiple points of view makes the novel hard to understand. In order to better appreciate Barn Burning, analysis of the use of multiple points of view with the help of Gerard Genette's focalization theory is necessary. Moreover, the application of Wayne Booth's ideas of implied author and discussion of Sarty's narrative reliability are also presented. Hopefully, it can help readers form a good habit of narrative thinking and understand the novel in a better way. 展开更多
关键词 WILLIAM FAULKNER BARN BURNING focalization implied AUTHOR NARRATIVE reliability
下载PDF
Different Focalizations of Catch-22
12
作者 房丽婷 《海外英语》 2017年第11期172-173,共2页
Studies about Catch-22 have been numerous,but the study of the novel’s narrative device is scarcely found.Thus,the narrative device of Catch-22 is analyzed in terms of focalization,one of Gernard Genette's narrat... Studies about Catch-22 have been numerous,but the study of the novel’s narrative device is scarcely found.Thus,the narrative device of Catch-22 is analyzed in terms of focalization,one of Gernard Genette's narrative theories.The analysis exposes the hypocrisy and meaninglessness of the bureaucratic behaviors and policies and simultaneously emphasizes bureaucracy’s devastative and corrosive effect on people. 展开更多
关键词 CATCH-22 narrative device Gernard Genette focalization BUREAUCRACY
下载PDF
Constraint on the focal mechanism of the 2011 Tohoku earthquake from the radial modes
13
作者 Weikun Chen Hao Ding 《Geodesy and Geodynamics》 EI CSCD 2024年第1期27-32,共6页
Different from other normal modes of the Earth’s free oscillation that depend on all the six components(M_(rr),M_(tt),M_(pp),M_(rt),M_(rp),and M_(tp))of the centroid moment tensor,the amplitudes of the radial modes d... Different from other normal modes of the Earth’s free oscillation that depend on all the six components(M_(rr),M_(tt),M_(pp),M_(rt),M_(rp),and M_(tp))of the centroid moment tensor,the amplitudes of the radial modes depend on the M_(rr)component(e.g.,scalar moment(M_(0)),dip(δ),and slip(λ))and hypocenter depth of the focal mechanism,and hence can be easily used to constrain these parameters of the focal mechanism.In this study,we use the superconducting gravimeter(SG)records after the 2011 Tohoku earthquake to analyze the radial modes_(0)S_(0)and_(1)S_(0).Based on the solutions of the focal mechanism provided by the GCMT and USGS,we can obtain the theoretical amplitudes of these two radial modes.Comparing the theoretical amplitudes with the observation amplitudes,it is found that there are obvious differences between the former and the latter,which means that the GCMT and USGS focal mechanisms cannot well represent the real focal mechanism of the 2011 event.Taking the GCMT solution as a reference and changing the depth and the three parameters of the M_(rr)moment,the scalar moment(M_(0))and the dip(δ)have significant influences,but the effects of the slip(λ)and the depth are minor.After comparisons,we provide a new constraint(M_(0)=5.8±0.09×10^(22)N·m,δ=10.1±0.08°,λ=88°,and depth=20 km)for the focal mechanism of the 2011 event.In addition,we further determine the center frequency(1.631567±2.6e^(-6)mHz)and quality factor(2046.4±50.1)of the_(1)S_(0)mode. 展开更多
关键词 focal mechanism Radial modes Gravity observation
下载PDF
Focal incidental colorectal fluorodeoxyglucose uptake:Should it be spotlighted?
14
作者 Haejun Lee Kyung-Hoon Hwang 《World Journal of Clinical Cases》 SCIE 2024年第15期2466-2474,共9页
Fluorine-18 fluorodeoxyglucose(F-18 FDG)positron emission tomography/computed tomography(PET/CT)has emerged as a cornerstone in cancer evaluation imaging,with a well-established history spanning several years.This ima... Fluorine-18 fluorodeoxyglucose(F-18 FDG)positron emission tomography/computed tomography(PET/CT)has emerged as a cornerstone in cancer evaluation imaging,with a well-established history spanning several years.This imaging modality,encompassing the examination of the body from the base of the skull to the upper thighs,comprehensively covers the chest and abdominopelvic regions in a singular scan,allowing for a holistic assessment of nearly the entire body,including areas of marginal interest.The inherent advantage of this expansive scan range lies in its potential to unveil unexpected incidental abnormal hypermetabolic areas.The identification of incidental focal FDG uptake within colorectal regions during PET/CT scans is not an uncommon occurrence,albeit fraught with challenges associated with non-specific FDG uptake.The presence of benign colorectal lesions or physiological uptake poses a particular obstacle,as these may manifest with FDG uptake levels that mimic malignancy.Consequently,physicians are confronted with a diagnostic dilemma when encountering abnormal FDG uptake in unexpected colorectal areas.Existing studies have presented divergent results concerning these uptakes.Standardized uptake value and its derivatives have served as pivotal metrics in quantifying FDG uptake in PET images.In this article,we aim to succinctly explore the distinctive characteristics of FDG,delve into imaging findings,and elucidate the clinical significance of incidental focal colorectal uptake.This discussion aims to contribute valuable insights into the nuanced interpretation of such findings,fostering a comprehensive understanding. 展开更多
关键词 focal INCIDENTAL COLORECTAL FLUORODEOXYGLUCOSE Positron emission tomography HYPERMETABOLISM
下载PDF
Unexpected focal fluorodeoxyglucose uptake in main organs;pass through or pass by?
15
作者 Haejun Lee Kyung-Hoon Hwang 《World Journal of Clinical Cases》 SCIE 2024年第11期1885-1899,共15页
Since the inception of fluorine-18 fluorodeoxyglucose(F-18 FDG),positron emission tomography/computed tomography(PET/CT)utilizing F-18 FDG has become widely accepted as a valuable imaging modality in the field of onco... Since the inception of fluorine-18 fluorodeoxyglucose(F-18 FDG),positron emission tomography/computed tomography(PET/CT)utilizing F-18 FDG has become widely accepted as a valuable imaging modality in the field of oncology,with global prevalence in clinical practice.Given that a single Torso PET/CT scan encompasses the anatomical region from the skull base to the upper thigh,the detection of incidental abnormal focal hypermetabolism in areas of limited clinical interest is both feasible and not uncommon.Numerous investigations have been undertaken to delineate the distinctive features of these findings,yet the outcomes have proven inconclusive.The incongruent results of these studies present a challenge for physicians,leaving them uncertain about the appropriate course of action.This article provides a succinct overview of the characteristics of fluorodeoxyglucose,followed by a comprehensive discussion of the imaging findings and clinical significance associated with incidental focal abnormal F-18 FDG activity in several representative organs.In conclusion,while the prevalence of unrecognized malignancy varies across organs,malignancies account for a substantial proportion,ranging from approximately one-third to over half,of incidental focal uptake.In light of these rates,physicians are urged to exercise vigilance in not disregarding unexpected uptake,facilitating more assured clinical decisions,and advocating for further active evaluation. 展开更多
关键词 INCIDENTAL focal INCIDENTALOMA FLUORODEOXYGLUCOSE Positron emission tomography HYPERMETABOLISM
下载PDF
Design and fabrication of compound varifocal lens driven by polydimethylsiloxane film elastic deformation
16
作者 缪文浩 韩泽峰 +3 位作者 赵瑞 梁忠诚 寇松峰 徐荣青 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期342-346,共5页
A compound varifocal lens based on electromagnetic drive technology is designed and fabricated, where the polydimethylsiloxane(PDMS) film acts as a driving component, while the PDMS biconvex lens and the plane-concave... A compound varifocal lens based on electromagnetic drive technology is designed and fabricated, where the polydimethylsiloxane(PDMS) film acts as a driving component, while the PDMS biconvex lens and the plane-concave lens form a coaxial compound lens system. The plane-concave lens equipped with driving coils is installed directly above the PDMS lens surrounded by the annular magnet. When different currents are applied, the annular magnet moves up and down, driving the PDMS film to undergo elastic deformation, and then resulting in longitudinal movement of the PDMS lens. The position change of the PDMS lens changes the focal length of the compound lens system. To verify the feasibility and practicability of this design, a prototype of our compound lens system is fabricated in experiment. Our proposed compound lens shows that its zoom ability reaches 9.28 mm when the current ranges from -0.20 A to 0.21 A. 展开更多
关键词 compound varifocal lens PDMS film elastic deformation focal length electromagnetic force zoom ability
下载PDF
A monolithic integrated medium wave Mercury Cadmium Telluride polarimetric focal plane array
17
作者 CHEN Ze-Ji HUANG You-Wen +4 位作者 PU En-Xiang XIAO Hui-Shan XU Shi-Chun QIN Qiang KONG Jin-Cheng 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2024年第4期479-489,共11页
A medium wave(MW)640×512(25μm)Mercury Cadmium Telluride(HgCdTe)polarimetric focal plane array(FPA)was demonstrated.The micro-polarizer array(MPA)has been carefully designed in terms of line grating structure opt... A medium wave(MW)640×512(25μm)Mercury Cadmium Telluride(HgCdTe)polarimetric focal plane array(FPA)was demonstrated.The micro-polarizer array(MPA)has been carefully designed in terms of line grating structure optimization and crosstalk suppression.A monolithic fabrication process with low damage was explored,which was verified to be compatible well with HgCdTe devices.After monolithic integration of MPA,NETD<9.5 mK was still maintained.Furthermore,to figure out the underlying mechanism that dominat⁃ed the extinction ratio(ER),specialized MPA layouts were designed,and the crosstalk was experimentally vali⁃dated as the major source that impacted ER.By expanding opaque regions at pixel edges to 4μm,crosstalk rates from adjacent pixels could be effectively reduced to approximately 2%,and promising ERs ranging from 17.32 to 27.41 were implemented. 展开更多
关键词 infrared physics infrared polarimetric focal plane array monolithic integration Mercury Cadmium Telluride extinction ratio
下载PDF
Carcinoembryonic antigen in the diagnosis,treatment,and follow-up of focal liver lesions
18
作者 Osman Nuri Dilek Dilaraİrem Arslan Kahraman Gökhan Kahraman 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第4期999-1007,共9页
In this editorial review,we comment on the article published in the recent issue of the World Journal of Gastrointestinal Surgery.Carcinoembryonic antigen(CEA)is a fetal glycoprotein and can be secreted in very small ... In this editorial review,we comment on the article published in the recent issue of the World Journal of Gastrointestinal Surgery.Carcinoembryonic antigen(CEA)is a fetal glycoprotein and can be secreted in very small amounts from healthy adults after birth.CEA is widely used not only for diagnostic tumor markers but also importantly for the management of some gastrointestinal tumors.The most common clinical use is surveillance for the monitoring of colorectal carcinoma.However,CEA can become elevated in several malign or benign characterized pathologies.Serum CEA level may vary depending on the location of the lesion,whether it metastasizes or not,and its histopathological characteristics.It has been determined that cases with high preoperative CEA have a more aggressive course and the risk of metastasis to the lymph tissue and liver increases.In this editorial review,we focused on evaluating the role of CEA in clinical practice with a holistic approach,including the diagnostic and prognostic significance of CEA in patients with focal liver lesions,the role of CEA in follow-up after definitive surgery,and also hepatic resection for metastasis,and the management of all patients with raised CEA. 展开更多
关键词 Carcinoembriyonic antigen LIVER focal liver lesions METASTASIS Surgery PROGNOSIS SURVEILLANCE
下载PDF
Towards fast focal mechanism inversion of shallow crustal earthquakes in the Chinese mainland
19
作者 Zhigao Yang Tairan Xu Jianhong Liang 《Earthquake Research Advances》 CSCD 2024年第2期36-44,共9页
We have developed an automatic regional focal mechanism inversion system based on the Earthquake Rapid Report(ERR) system and the real-time three-component seismic waveform stream of 1 000 broadband seismic stations p... We have developed an automatic regional focal mechanism inversion system based on the Earthquake Rapid Report(ERR) system and the real-time three-component seismic waveform stream of 1 000 broadband seismic stations provided by the China Earthquake Networks Center(CENC). The system can rapidly provide a double couple solution and centroid depth within 5–15 min after receiving earthquake information from the ERR system.The data processing is triggered by earthquake information obtained from the ERR system. The system is capable of determining the focal mechanism of all shallow-depth earthquakes in the Chinese mainland with a magnitude of 5.5–6.5. It utilizes waveform data recorded by seismic stations located within 500 km from the epicenter,enabling the reporting of a focal mechanism solution within 5–15 min of an earthquake occurrence. Additionally,the system can assign a corresponding grade(A B C) to the focal mechanism solution. We processed a total of 301earthquakes that occurred from 2021 to June 2022, and after the quality control, 166 of them were selected.These selected solutions were manually checked, and 160 of them were compiled in a focal mechanism catalog.This catalog can be conveniently downloaded online via the Internet. The automatic focal mechanism solution of earthquakes in eastern China exhibits a good agreement with that provided by the Global Centroid Moment Tensor(GCMT), when available. The average Kagan angle between this catalog and GCMT is 22°, and the average difference in MWis 0.17. Furthermore, compared with GCMT, the minimum magnitude of our catalog has been reduced from approximately 5.0 to 4.0. The correlation between the centroid depth and crustal thickness in the Chinese mainland confirms the distribution of the centroid depth. 展开更多
关键词 Automatic focal mechanism solution Chinese mainland Moment magnitude Centroid depth
下载PDF
Imaging features and management of focal liver lesions
20
作者 Gökhan Kahraman Kemal Murat Haberal Osman Nuri Dilek 《World Journal of Radiology》 2024年第6期139-167,共29页
Notably,the number of incidentally detected focal liver lesions(FLLs)has increa-sed dramatically in recent years due to the increased use of radiological imaging.The diagnosis of FLLs can be made through a well-docume... Notably,the number of incidentally detected focal liver lesions(FLLs)has increa-sed dramatically in recent years due to the increased use of radiological imaging.The diagnosis of FLLs can be made through a well-documented medical history,physical examination,laboratory tests,and appropriate imaging methods.Although benign FLLs are more common than malignant ones in adults,even in patients with primary malignancy,accurate diagnosis of incidental FLLs is of utmost clinical significance.In clinical practice,FLLs are frequently evaluated non-invasively using ultrasound(US),computed tomography(CT),and magnetic resonance imaging(MRI).Although US is a cost-effective and widely used imaging method,its diagnostic specificity and sensitivity for FLL characterization are limited.FLLs are primarily characterized by obtaining enhancement patterns through dynamic contrast-enhanced CT and MRI.MRI is a problem-solving method with high specificity and sensitivity,commonly used for the evaluation of FLLs that cannot be characterized by US or CT.Recent technical advancements in MRI,along with the use of hepatobiliary-specific MRI contrast agents,have significantly improved the success of FLL characterization and reduced unnece-ssary biopsies.The American College of Radiology(ACR)appropriateness criteria are evidence-based recommendations intended to assist clinicians in selecting the optimal imaging or treatment option for their patients.ACR Appropriateness Criteria Liver Lesion-Initial Characterization guideline provides recommend-ations for the imaging methods that should be used for the characterization of incidentally detected FLLs in various clinical scenarios.The American College of Gastroenterology(ACG)Clinical Guideline offers evidence-based recommend-ations for both the diagnosis and management of FLL.American Association for the Study of Liver Diseases(AASLD)Practice Guidance provides an approach to the diagnosis and management of patients with hepatocellular carcinoma.In this article,FLLs are reviewed with a comprehensive analysis of ACR Appropri-ateness Criteria,ACG Clinical Guideline,AASLD Practice Guidance,and current medical literature from peer-reviewed journals.The article includes a discussion of imaging methods used for the assessment of FLL,current recommended imaging techniques,innovations in liver imaging,contrast agents,imaging features of common nonmetastatic benign and malignant FLL,as well as current management recommendations. 展开更多
关键词 focal liver lesions IMAGING ULTRASONOGRAPHY Computed tomography Magnetic resonance imaging MANAGEMENT
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部