期刊文献+
共找到55,773篇文章
< 1 2 250 >
每页显示 20 50 100
Evaluation of Entrance Skin Dose from Paediatric Diagnostic X-Ray Examination
1
作者 Moromoke Oluwayemisi Adelayi Oladele Samuel Ajayi 《Open Journal of Radiology》 2023年第1期26-33,共8页
As children are prone to be more radiosensitive than adults, it is imperative to assess the Entrance Skin Doses (ESDs) for patients being examined by X-rays, in order to ensure the optimization of dose while consideri... As children are prone to be more radiosensitive than adults, it is imperative to assess the Entrance Skin Doses (ESDs) for patients being examined by X-rays, in order to ensure the optimization of dose while considering a number of other fickles. The ESD received by 50 paediatrics (aged 1-13 years) undergoing 8 types of X-ray examinations were measured at Federal Teaching Hospital, Ido-Ekiti, Ekiti, Nigeria, within a period of February 2019 to March 2020 using thermoluminescent dosimeters. The mean ± SD of ESDs were 0.85 ± 0.32, 2.04 ± 0.75, 0.60 ± 0.07, 0.62 ± 0.22, 0.57 ± 0.24, 1.75 ± 0.76, 0.93 ± 0.31 and 0.63 ± 0.06 mGy for Chest, Skull, Hand, Forearm, Knee, Abdomen, Leg and Feet, respectively. The mean ESDs were found to be within the recommended reference dose in all examinations, except for the Chest examination which was higher. The data obtained in this study will serve as existing data in Nigeria for future research works, as it would assist in optimizing dose to patients, especially the paediatrics. 展开更多
关键词 Entrance Skin Dose PAEDIATRICS x-rays
下载PDF
X-ray Examination of the Complex Adenosine, Guanosine and Cytidine with UO2^2+ Ions
2
作者 Aibassov Yerkin Zhakenovich Yemelyanova Valentina +6 位作者 Shakieva Tatyana Nakisbekov Narymzhan Tussupbaev Nessipbay Abenov Bakhyt Bulenbayev Maxat Dossumova Binara Blagikh Evgeniy 《Journal of Chemistry and Chemical Engineering》 2015年第6期408-414,共7页
Interaction of dioxouranitm (VI) UO2^2+ ion with Adenosine-5'-triphosphate, Guanosine-5'-triphosphate and 3ytidine-5'-triphosphate were obtained a complexs of Adenosine, Guanosine and Cytidine with uranium UO2^2... Interaction of dioxouranitm (VI) UO2^2+ ion with Adenosine-5'-triphosphate, Guanosine-5'-triphosphate and 3ytidine-5'-triphosphate were obtained a complexs of Adenosine, Guanosine and Cytidine with uranium UO2^2+ ions and X-ray nethod to explore these complexes. 展开更多
关键词 DNA uranyl ion x-ray ADENOSINE GUANOSINE Cytidine complexs.
下载PDF
X-ray Examination of the Complex Adenosine with UO2^2+ and Th4^+ Ions
3
作者 Aibassov Erkin Zhakenovich Yemelyanova Valentina Stepanovna +6 位作者 Shakieva Tatyana Tussupbaev Nessipbay Nakisbekov Narymzhan Abenov Bakhyt Bulenbayev Maxat Dossumova Binara Blagikh Evgeniy 《Journal of Chemistry and Chemical Engineering》 2015年第7期477-479,共3页
The authors studied the interaction of dioxouranium (VI) UO2^2+ and thorium Th^4+ ions with ATP (5'-adenosine 5'-triphosphate) and obtained a complex of adenosine with uranium UO2^2+ and thorium Th^4+ ions a... The authors studied the interaction of dioxouranium (VI) UO2^2+ and thorium Th^4+ ions with ATP (5'-adenosine 5'-triphosphate) and obtained a complex of adenosine with uranium UO2^2+ and thorium Th^4+ ions and used X-ray method to explore these complexes. 展开更多
关键词 Complex Adenosine dioxouranium UO2^2+ Th^4+ ions x-ray.
下载PDF
Infrared Spectra and X-ray Examination of the Complex Albumin Human with UO2^2+
4
作者 Aibassov Yerkin Zhakenovlch Yemelyanova Valentina +6 位作者 Shakieva Tatyana Nakisbekov Narymzhan Tussupbaev Nessipbay Abenov Bakhyt Bulenbayev Maxat Dossumova Binara Blagikh Evgeniy 《Journal of Chemistry and Chemical Engineering》 2015年第5期324-328,共5页
Reaction dioxouraniun (VI) UO22+ ion with human serum albumin was prepared: human albumin with uranium UO22+ ion and the X-ray method of investigation of these complexes. The authors have shown that Human Albumin... Reaction dioxouraniun (VI) UO22+ ion with human serum albumin was prepared: human albumin with uranium UO22+ ion and the X-ray method of investigation of these complexes. The authors have shown that Human Albumin may be used to remove highly toxic uranyl UO22+ ions. 展开更多
关键词 Albumin serum human dioxouraniun (VI) UO22+ ion x-ray complex.
下载PDF
Effectiveness of Histopathological Examination of Ultrasound-guided Puncture Biopsy Samples for Diagnosis of Extrapulmonary Tuberculosis
5
作者 GU Wen Fei SHI Xia +5 位作者 MA Xin YU Jun Lei XU Jin Chuan QIAN Cheng Cheng HU Zhi Dong ZHANG Hui 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第2期170-177,共8页
Objective To evaluate the diagnostic value of histopathological examination of ultrasound-guided puncture biopsy samples in extrapulmonary tuberculosis(EPTB).Methods This study was conducted at the Shanghai Public Hea... Objective To evaluate the diagnostic value of histopathological examination of ultrasound-guided puncture biopsy samples in extrapulmonary tuberculosis(EPTB).Methods This study was conducted at the Shanghai Public Health Clinical Center.A total of 115patients underwent ultrasound-guided puncture biopsy,followed by MGIT 960 culture(culture),smear,Gene Xpert MTB/RIF(Xpert),and histopathological examination.These assays were performed to evaluate their effectiveness in diagnosing EPTB in comparison to two different diagnostic criteria:liquid culture and composite reference standard(CRS).Results When CRS was used as the reference standard,the sensitivity and specificity of culture,smear,Xpert,and histopathological examination were(44.83%,89.29%),(51.72%,89.29%),(70.11%,96.43%),and(85.06%,82.14%),respectively.Based on liquid culture tests,the sensitivity and specificity of smear,Xpert,and pathological examination were(66.67%,72.60%),(83.33%,63.01%),and(92.86%,45.21%),respectively.Histopathological examination showed the highest sensitivity but lowest specificity.Further,we found that the combination of Xpert and histopathological examination showed a sensitivity of 90.80%and a specificity of 89.29%.Conclusion Ultrasound-guided puncture sampling is safe and effective for the diagnosis of EPTB.Compared with culture,smear,and Xpert,histopathological examination showed higher sensitivity but lower specificity.The combination of histopathology with Xpert showed the best performance characteristics. 展开更多
关键词 Extrapulmonary tuberculosis DIAGNOSIS BIOPSY Histopathological examination Puncture samples
下载PDF
Linear endoscopic ultrasound:Current uses and future perspectives in mediastinal examination
6
作者 Eyad Gadour Sarah Al Ghamdi +4 位作者 Bogdan Miutescu Hossam E Shaaban Zeinab Hassan Aymen Almuhaidb Hussein H Okasha 《World Journal of Gastroenterology》 SCIE CAS 2024年第33期3803-3809,共7页
This editorial elaborates on the current and future applications of linear endoscopic ultrasound(EUS),a substantial diagnostic and therapeutic modality for various anatomical regions.The scope of endosonographic asses... This editorial elaborates on the current and future applications of linear endoscopic ultrasound(EUS),a substantial diagnostic and therapeutic modality for various anatomical regions.The scope of endosonographic assessment is broad and,among other factors,allows for the evaluation of the mediastinal anatomy and related pathologies,such as mediastinal lymphadenopathy and the staging of central malignant lung lesions.Moreover,EUS assessment has proven more accurate in detecting small lesions missed by standard imaging examinations,such as computed tomography or magnetic resonance imaging.We focus on its current uses in the mediastinum,including lung and esophageal cancer staging,as well as evaluating mediastinal lymphadenopathy and submucosal lesions.The editorial also explores future perspectives of EUS in mediastinal examination,including ultrasound-guided therapies,artificial intelligence integration,advancements in mediastinal modalities,and improved diagnostic approaches for various mediastinal lesions. 展开更多
关键词 Linear endoscopic ultrasound Mediastinal examination Lung cancer Computed tomography Magnetic resonance imaging
下载PDF
An Empirical Study of the Socratic Method in Nongraded English Teaching in Senior High School Under the Background of the New National College Entrance Examination
7
作者 Chen Yilong 《Contemporary Social Sciences》 2024年第2期139-155,共17页
With the reform of the New National College Entrance Examination(Gaokao),the nongraded education will become an inevitable trend.In senior high school,the traditional test-oriented education is popular.The knowledge i... With the reform of the New National College Entrance Examination(Gaokao),the nongraded education will become an inevitable trend.In senior high school,the traditional test-oriented education is popular.The knowledge is mainly taught by the teachers,and the students passively absorb it.This study examines a problem-oriented Socratic experiment in nongraded English teaching in senior high school.The teachers seek output from students,who respond by interpreting questions,fostering critical thinking,and enhancing problem-solving skills.This teaching experiment indicates that the Socratic method has a significant positive effect on cultivating nongraded senior high English students’critical thinking under the New National College Entrance Examination. 展开更多
关键词 new national college entrance examination nongraded education exercise teaching Socratic method
下载PDF
Profile of Radiological Examinations in the Radiology and Medical Imaging Department of the Medical Clinic “KALALE” in Mali
8
作者 Traore Ousmane Diakite Siaka +9 位作者 Sidibe Drissa Massan Diallo Ousmane Wélé Keita Modibo Diarra Ouncoumba Dembele Mamadou N’Diaye Mamadou Sangare Modibo Coulibaly Ibrahim Traore Chieck B Keita Adama Diaman 《Open Journal of Medical Imaging》 2024年第3期128-136,共9页
Introduction: Radiology and medical imaging examinations bring together the means of acquiring and restoring images of the human body from different physical phenomena such as the absorption of X-rays, nuclear magneti... Introduction: Radiology and medical imaging examinations bring together the means of acquiring and restoring images of the human body from different physical phenomena such as the absorption of X-rays, nuclear magnetic resonance, reflection of ultrasound waves or radioactivity, with which we sometimes associate optical imaging techniques such as endoscopy. The objective of our study was to study the profile of radiological examinations in the radiology and medical imaging department of the “KALALE” medical clinic. Methodology: This was a descriptive, prospective study that took place over a period of six (6) months in the radiology and medical imaging department of the “KALALE” medical clinic and the centers of health of communes III and IV of Bamako in Mali. Data collection was carried out on a survey form. The parameters studied were sociodemographic data, clinical data, radiological data. Results: We recorded 6030 radiology examinations of which 19% of the examination frequency cases came from the “KALALE” medical clinic and 81% of the cases were referrals from the reference health centers of communes III and IV. There were 1500 X-rays or 24.9% of cases including 54% cases of bone X-rays;5% of cases of skull and face X-rays;5% of cases of Intravenous Urography (IVU);4% of cases of Hysterosalpingography (HSG);3% of cases of Retrograde Ureterocystography (UCR) and 1% of cases of X-ray of the Abdomen without preparation (ASP). We found 4530 ultrasounds or 75.1% of cases. Conclusion: Medical imaging has become essential in the study of the human body and now constitutes an essential tool for the detection and treatment of most pathologies, from simple fractures to the most serious tumors. 展开更多
关键词 PROFILE Radiological examinations KALALE Clinic MALI
下载PDF
Improved Mechanism for Detecting Examinations Impersonations in Public Higher Learning Institutions: Case of the Mwalimu Nyerere Memorial Academy (MNMA)
9
作者 Jasson Lwangisa Domition Rogers Philip Bhalalusesa Selemani Ismail 《Journal of Computer and Communications》 2024年第9期160-187,共28页
Currently, most public higher learning institutions in Tanzania rely on traditional in-class examinations, requiring students to register and present identification documents for examinations eligibility verification.... Currently, most public higher learning institutions in Tanzania rely on traditional in-class examinations, requiring students to register and present identification documents for examinations eligibility verification. This system, however, is prone to impersonations due to security vulnerabilities in current students’ verification system. These vulnerabilities include weak authentication, lack of encryption, and inadequate anti-counterfeiting measures. Additionally, advanced printing technologies and online marketplaces which claim to produce convincing fake identification documents make it easy to create convincing fake identity documents. The Improved Mechanism for Detecting Impersonations (IMDIs) system detects impersonations in in-class exams by integrating QR codes and dynamic question generation based on student profiles. It consists of a mobile verification app, built with Flutter and communicating via RESTful APIs, and a web system, developed with Laravel using HTML, CSS, and JavaScript. The two components communicate through APIs, with MySQL managing the database. The mobile app and web server interact to ensure efficient verification and security during examinations. The implemented IMDIs system was validated by a mobile application which is integrated with a QR codes scanner for capturing codes embedded in student Identity Cards and linking them to a dynamic question generation model. The QG model uses natural language processing (NLP) algorithm and Question Generation (QG) techniques to create dynamic profile questions. Results show that the IMDIs system could generate four challenging profile-based questions within two seconds, allowing the verification of 200 students in 33 minutes by one operator. The IMDIs system also tracks exam-eligible students, aiding in exam attendance and integrates with a Short Message Service (SMS) to report impersonation incidents to a dedicated security officer in real-time. The IMDIs system was tested and found to be 98% secure, 100% convenient, with a 0% false rejection rate and a 2% false acceptance rate, demonstrating its security, reliability, and high performance. 展开更多
关键词 Natural Language Processing (NLP) Model Impersonations Detection Dynamic Challenging Questions Traditional-in-Class examination and Impersonation Detection
下载PDF
Research on the Evaluation of the Implementation Effect of Curriculum Examination Reform: Taking the Course of “Introduction to Language” as an Example
10
作者 Qianwen Yi 《Journal of Contemporary Educational Research》 2024年第3期193-198,共6页
“Introduction to Language,”as the core course of the English major,mainly reveals the basic laws of language,enabling the students to have the ability to apply linguistic theories to explain language phenomena and s... “Introduction to Language,”as the core course of the English major,mainly reveals the basic laws of language,enabling the students to have the ability to apply linguistic theories to explain language phenomena and solve specific language problems.This course is highly theoretical and has a certain degree of difficulty.The evaluation of student grades has always been based on examination reform,but several problems have been encountered during the implementation process.This article analyzes the current situation of the reform and implementation of the“Introduction to Language”course examination in applied universities and puts forth suggestions and specific measures to improve the assessment of the course,aiming to enhance the teaching effectiveness of the course and scientifically and comprehensively evaluate students’abilities. 展开更多
关键词 Introduction to Language examination reform Implementation effect
下载PDF
Awareness, Practice and Intention to Practice Testicular Self-Examination among Professional Working Males in Ghana
11
作者 Ninon P. Amertil Cecilia Amponsem-Boateng +2 位作者 Elikem K. Ayitey Doris Grace Kpongboe Pamphil Igman 《Journal of Cancer Therapy》 2024年第10期331-345,共15页
Background: The aetiology of Testicular Cancer (TC) is still unknown to researchers but many of the associated risk factors have been identified. These include family history, age, racial origin, cryptorchidism, uroge... Background: The aetiology of Testicular Cancer (TC) is still unknown to researchers but many of the associated risk factors have been identified. These include family history, age, racial origin, cryptorchidism, urogenital malformations, testicular atrophy, and infertility. Given the lack of scientific data on the causes of the disease, it has been asserted in previous studies that the promotion of awareness and early detection are prerequisites to mitigating risks of metastasis as well as improving survival. This study is to assess the awareness, practice, and intention to practice testicular self-examination among professional working males in Accra. Methods: A quantitative cross-sectional design with a structured research instrument was used to collect data from respondants. The purposive and convenience sampling techniques were used to collect data from 300 men at Accra in Ghana. The study was conducted at two (2) Universities and a Senior High school at Accra in Ghana. The data was then analysed using descriptive statistics, logistic regression, multiple linear regression, and structural equation modeling. Results: From the study findings, 37% of male participants rated their knowledge of testicular self-examination and related symptoms as good, 28% of participants practised testicular self-examination monthly, while 65% of respondents expressed their intention to practice monthly testicular self-examination. The findings from logistic regression demonstrated that level of education, age, and marital status of participants had a significant influence on testicular self-examination. Additionally, the multiple linear regression results revealed knowledge and self-efficacy significantly predict testicular self-examination intention. The path coefficient results from the structural equation model are consistent with results from the regression models. Conclusion: This research is the first to investigate testicular self-examination among men in Ghana. The findings revealed awareness and practice of TSE are low among participants. Therefore, the research findings would improve the expertise of physicians and nurses in providing counsel, intervention, and support for patients at risk of testicular cancer. 展开更多
关键词 Testicular Cancer Testicular Self-examination Awareness and Practice Health Promotion Men’s Health
下载PDF
ISHD:Intelligent Standing Human Detection of Video Surveillance for the Smart Examination Environment 被引量:1
12
作者 Wu Song Yayuan Tang +1 位作者 Wenxue Tan Sheng Ren 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第10期509-526,共18页
In the environment of smart examination rooms, it is important to quickly and accurately detect abnormal behavior(human standing) for the construction of a smart campus. Based on deep learning, we propose an intellige... In the environment of smart examination rooms, it is important to quickly and accurately detect abnormal behavior(human standing) for the construction of a smart campus. Based on deep learning, we propose an intelligentstanding human detection (ISHD) method based on an improved single shot multibox detector to detect thetarget of standing human posture in the scene frame of exam room video surveillance at a specific examinationstage. ISHD combines the MobileNet network in a single shot multibox detector network, improves the posturefeature extractor of a standing person, merges prior knowledge, and introduces transfer learning in the trainingstrategy, which greatly reduces the computation amount, improves the detection accuracy, and reduces the trainingdifficulty. The experiment proves that the model proposed in this paper has a better detection ability for the smalland medium-sized standing human body posture in video test scenes on the EMV-2 dataset. 展开更多
关键词 Deep learning object detection video surveillance of exam room smart examination environment
下载PDF
M^(3)Res-Transformer:新冠肺炎胸部X-ray图像识别模型 被引量:1
13
作者 周涛 刘赟璨 +3 位作者 侯森宝 常晓玉 叶鑫宇 陆惠玲 《电子学报》 EI CAS CSCD 北大核心 2024年第2期589-601,共13页
新冠肺炎(COVID-19)自爆发以来严重影响人类生命健康,近年来残差神经网络广泛应用于COVID-19识别任务中,辅助医生快速地诊断COVID-19患者,但是COVID-19图像病变区域形状复杂、大小不一,与周围组织的边界模糊,导致网络难以提取有效特征.... 新冠肺炎(COVID-19)自爆发以来严重影响人类生命健康,近年来残差神经网络广泛应用于COVID-19识别任务中,辅助医生快速地诊断COVID-19患者,但是COVID-19图像病变区域形状复杂、大小不一,与周围组织的边界模糊,导致网络难以提取有效特征.本文针对上述问题,提出一种M^(3)Res-Transformer的新冠肺炎胸部X-ray图像识别模型,采用Res-Transformer作为模型的主干网络,结合ResNet和ViT,有效地整合局部病变特征和全局特征;设计混合残差注意力模块(mixed residual attention Module,mraM),同时考虑通道和空间位置的相互依赖性,增强网络的特征表达能力;为了增大感受野,提取多尺度特征,通过叠加具有不同扩张率的扩张卷积构造多尺度扩张残差模块(multiscale dilated residual Module,mdrM),根据不同层次特征尺度的差异,使用3个逐渐收缩尺度的mdrM进行多尺度特征提取;提出上下文交叉感知模块(contextual cross-awareness Module,ccaM),使用深层特征中的语义信息来引导浅层特征,然后将浅层特征中的空间信息嵌入深层特征中,采用交叉加权注意力机制高效聚合深层和浅层特征,获得更丰富的上下文信息.为了验证本文所提模型的有效性,在新冠肺炎胸部X-ray图像数据集上进行实验,与先进的CNN分类模型、融合不同注意力机制的ResNet50模型、基于Transformer的分类模型对比以及消融实验.结果表明,本文所提模型的Acc、Pre、Rec、F1-Score与Spe指标分别为96.33%、96.36%、96.33%、96.35%与96.26%,在COVID-19胸部X-ray图像识别任务中有效提升了识别精度,并通过可视化方法对其进行进一步验证,为COVID-19的辅助诊断提供重要的参考价值. 展开更多
关键词 COVID-19 胸部x-ray图像 残差神经网络 vision transformer 注意力机制
下载PDF
X-ray在鱼体组织及微量元素检测中的应用
14
作者 宋一帆 张胜茂 +4 位作者 张衡 唐峰华 张寒野 石永闯 崔雪森 《应用光学》 CAS 北大核心 2024年第1期166-176,共11页
鱼类硬质组织物,特别是骨骼支持鱼体和保护其体内器官的组织,对其进行特征检测分析是研究鱼类游泳运动、鱼类解剖、鱼体建模等的数据基础。随着X-ray技术的发展和国产设备的广泛应用,其仪器设备成本明显降低,使得X-ray在渔业研究与自动... 鱼类硬质组织物,特别是骨骼支持鱼体和保护其体内器官的组织,对其进行特征检测分析是研究鱼类游泳运动、鱼类解剖、鱼体建模等的数据基础。随着X-ray技术的发展和国产设备的广泛应用,其仪器设备成本明显降低,使得X-ray在渔业研究与自动化生产中的应用成为可能。首先介绍了X-ray技术的基本原理与其在鱼体组织检测中的应用,X-ray技术在鱼体组织及微量元素检测中的应用主要分为鱼类组织器官的无损检测和鱼体微量元素检测两部分,其中分别介绍了包括照相法、数字成像法、衍射技术和吸收光谱法等X-ray技术;然后综述其在鱼体组织器官建模、鱼骨检测、鱼类化石研究、鱼耳石分析和鱼体微量元素检测方面的应用,总结了Xray在渔业领域应用中存在的问题;最后对X-ray的渔业应用方向进行展望。 展开更多
关键词 x-ray 鱼体骨骼 鱼类耳石 鱼体建模 鱼体微量元素
下载PDF
Global hybrid simulations of soft X-ray emissions in the Earth’s magnetosheath 被引量:2
15
作者 Jin Guo TianRan Sun +6 位作者 San Lu QuanMing Lu Yu Lin XueYi Wang Chi Wang RongSheng Wang Kai Huang 《Earth and Planetary Physics》 EI CSCD 2024年第1期47-58,共12页
Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the magnetosphere.Soft X-ray imaging ... Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the magnetosphere.Soft X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional(2-D)global view from a satellite.By performing 3-D global hybrid-particle-in-cell(hybrid-PIC)simulations,we obtain soft X-ray images of Earth’s magnetopause under different solar wind conditions,such as different plasma densities and directions of the southward interplanetary magnetic field.In all cases,magnetic reconnection occurs at low latitude magnetopause.The soft X-ray images observed by a hypothetical satellite are shown,with all of the following identified:the boundary of the magnetopause,the cusps,and the magnetosheath.Local X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations(up to 160%);however,the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well,indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray images.Moreover,the magnetopause boundary can be identified using multiple viewing geometries.We also find that solar wind conditions have little effect on the magnetopause identification.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will provide X-ray images of the magnetopause for the first time,and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective,with particle kinetic effects considered. 展开更多
关键词 MAGNETOPAUSE x-ray emissivity x-ray imaging SMILE global hybrid-PIC simulation
下载PDF
The Soft X-ray Imager(SXI)on the SMILE Mission 被引量:4
16
作者 S.Sembay A.L.Alme +83 位作者 D.Agnolon T.Arnold A.Beardmore A.Belén Balado Margeli C.Bicknell C.Bouldin G.Branduardi-Raymont T.Crawford J.P.Breuer T.Buggey G.Butcher R.Canchal J.A.Carter A.Cheney Y.Collado-Vega H.Connor T.Crawford N.Eaton C.Feldman C.Forsyth T.Frantzen G.Galgóczi J.Garcia G.Y.Genov C.Gordillo H-P.Gröbelbauer M.Guedel Y.Guo M.Hailey D.Hall R.Hampson J.Hasiba O.Hetherington A.Holland S-Y.Hsieh M.W.J.Hubbard H.Jeszenszky M.Jones T.Kennedy K.Koch-Mehrin S.Kögl S.Krucker K.D.Kuntz C.Lakin G.Laky O.Lylund A.Martindale J.Miguel Mas Hesse R.Nakamura K.Oksavik N.Østgaard H.Ottacher R.Ottensamer C.Pagani S.Parsons P.Patel J.Pearson G.Peikert F.S.Porter T.Pouliantis B.H.Qureshi W.Raab G.Randal A.M.Read N.M.M.Roque M.E.Rostad C.Runciman S.Sachdev A.Samsonov M.Soman D.Sibeck S.Smit J.Søndergaard R.Speight S.Stavland M.Steller TianRan Sun J.Thornhill W.Thomas K.Ullaland B.Walsh D.Walton C.Wang S.Yang 《Earth and Planetary Physics》 EI CSCD 2024年第1期5-14,共10页
The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese... The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States. 展开更多
关键词 Soft x-ray Imaging micropore optics large area CCD
下载PDF
Two methods for separating the magnetospheric solar wind charge exchange soft X-ray emission from the diffuse X-ray background 被引量:2
17
作者 YingJie Zhang TianRan Sun +5 位作者 JenniferACarter WenHao Liu Steve Sembay ShuiNai Zhang Li Ji Chi Wang 《Earth and Planetary Physics》 EI CSCD 2024年第1期119-132,共14页
Solar wind charge exchange(SWCX)is the process of solar wind high-valence ions exchanging charges with neutral components and generating soft X-rays.Recently,detecting the SWCX emission from the magnetosphere is propo... Solar wind charge exchange(SWCX)is the process of solar wind high-valence ions exchanging charges with neutral components and generating soft X-rays.Recently,detecting the SWCX emission from the magnetosphere is proposed as a new technique to study the magnetosphere using panoramic soft X-ray imaging.To better prepare for the data analysis of upcoming magnetospheric soft X-ray imaging missions,this paper compares the magnetospheric SWCX emission obtained by two methods in an XMM-Newton observation,during which the solar wind changed dramatically.The two methods differ in the data used to fit the diffuse X-ray background(DXB)parameters in spectral analysis.The method adding data from the ROSAT All-Sky Survey(RASS)is called the RASS method.The method using the quiet observation data is called the Quiet method,where quiet observations usually refer to observations made by the same satellite with the same target but under weaker solar wind conditions.Results show that the spectral compositions of magnetospheric SWCX emission obtained by the two methods are very similar,and the changes in intensity over time are highly consistent,although the intensity obtained by the RASS method is about 2.68±0.56 keV cm^(-2)s^(-1)sr^(-1)higher than that obtained by the Quiet method.Since the DXB intensity obtained by the RASS method is about 2.84±0.74 keV cm^(-2)s^(-1)sr^(-1)lower than that obtained by the Quiet method,and the linear correlation coefficient between the difference of SWCX and DXB obtained by the two methods in diffe rent energy band is close to-1,the diffe rences in magnetospheric SWCX can be fully attributed to the diffe rences in the fitted DXB.The difference between the two methods is most significant when the energy is less than 0.7 keV,which is also the main energy band of SWCX emission.In addition,the difference between the two methods is not related to the SWCX intensity and,to some extent,to solar wind conditions,because SWCX intensity typically va ries with the solar wind.In summary,both methods are robust and reliable,and should be considered based on the best available options. 展开更多
关键词 solar wind charge exchange(SWCX) ROSAT All-Sky Survey(RASS) soft x-ray x-ray imaging MAGNETOSPHERE
下载PDF
Exploring battery material failure mechanisms through synchrotron X-ray characterization techniques 被引量:1
18
作者 Lingzhe Fang Xiaozhao Liu Tao Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期128-135,共8页
Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synch... Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synchrotron-based X-ray techniques with high flux and brightness play a key role in understanding degradation mechanisms.In this comprehensive review,we summarize recent advancements in degra-dation modes and mechanisms that were revealed by synchrotron X-ray methodologies.Subsequently,an overview of X-ray absorption spectroscopy and X-ray scattering techniques is introduced for charac-terizing failure phenomena at local coordination atomic environment and long-range order crystal struc-ture scale,respectively.At last,we envision the future of exploring material failure mechanism. 展开更多
关键词 Battery failure Synchrotron-based techniques x-ray scattering x-ray absorption spectroscopy
下载PDF
Finding the magnetopause location using soft X-ray observations and a statistical inverse method 被引量:1
19
作者 Gonzalo Cucho-Padin Hyunju Connor +2 位作者 Jaewoong Jung Brian Walsh David G.Sibeck 《Earth and Planetary Physics》 EI CSCD 2024年第1期184-203,共20页
Variability in the location and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental process that enables the transfer of mass,energy,and momentum from the solar wind into the magneto... Variability in the location and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental process that enables the transfer of mass,energy,and momentum from the solar wind into the magnetosphere.The spatial and temporal properties of the magnetopause,under varying solar and magnetospheric conditions,remain largely unknown because empirical studies using in-situ observations are challenging to interpret.Global wide field-of-view(FOV)imaging is the only means to simultaneously observe the spatial distribution of the plasma properties over the vast dayside magnetospheric region and,subsequently,quantify the energy transport from the interplanetary medium into the terrestrial magnetosphere.Two upcoming missions,ESA/CAS SMILE and NASA’s LEXI will provide wide-field imagery of the dayside magnetosheath in soft X-rays,an emission generated by charge exchange interactions between high charge-state heavy ions of solar wind origin and exospheric neutral atoms.High-cadence two-dimensional observations of the magnetosheath will allow the estimation of dynamic properties of its inner boundary,the magnetopause,and enable studies of its response to changes in the solar wind dynamic pressure and interplanetary magnetic field orientation.This work introduces a statistically-based estimation approach based on inverse theory to estimate the spatial distribution of magnetosheath soft X-ray emissivities and,with this,identify the location of the magnetopause over the Sun−Earth line.To do so,we simulate the magnetosheath structure using the MHD-based OpenGGCM model and generate synthetic soft X-ray images using LEXI’s orbit and attitude information.Our results show that 3-D estimations using the described statistically-based technique are robust against Poisson-distributed shot noise inherent to soft X-ray images.Also,our proposed methodology shows that the accuracy of both three-dimensional(3-D)estimation and the magnetopause standoff distance calculation highly depends on the observational point. 展开更多
关键词 MAGNETOPAUSE soft x-ray TOMOGRAPHY
下载PDF
Combined molybdenum target X-ray and magnetic resonance imaging examinations improve breast cancer diagnostic efficacy 被引量:14
20
作者 Wen-Quan Gu Sun-Mei Cai +3 位作者 Wei-Dong Liu Qi Zhang Ying Shi Li-Juan Du 《World Journal of Clinical Cases》 SCIE 2022年第2期485-491,共7页
BACKGROUND Early-stage breast cancer patients often lack specific clinical manifestations,making diagnosis difficult.Molybdenum target X-ray and magnetic resonance imaging(MRI)examinations both have their own advantag... BACKGROUND Early-stage breast cancer patients often lack specific clinical manifestations,making diagnosis difficult.Molybdenum target X-ray and magnetic resonance imaging(MRI)examinations both have their own advantages.Thus,a combined examination methodology may improve early breast cancer diagnoses.AIM To explore the combined diagnostic efficacy of molybdenum target X-ray and MRI examinations in breast cancer.METHODS Patients diagnosed with breast cancer at our hospital from March 2019 to April 2021 were recruited,as were the same number of patients during the same period with benign breast tumors.Both groups underwent molybdenum target X-ray and MRI examinations,and diagnoses were given based on each exam.The single(i.e.,X-ray or MRI)and combined(i.e.,using both methods)diagnoses were counted,and the MRI-related examination parameters(e.g.,T-wave peak,peak and early enhancement rates,and apparent diffusion coefficient)were compared between the groups.RESULTS In total,63 breast cancer patients and 63 benign breast tumor patients were recruited.MRI detected 53 breast cancer cases and 61 benign breast tumor cases.Molybdenum target X-ray detected 50 breast cancer cases and 60 benign breast tumor cases.The combined methodology detected 61 breast cancer cases and 61 benign breast tumor cases.The sensitivity(96.83%)and accuracy(96.83%)of the combined methodology were higher than single-method MRI(84.13%and 90.48%,respectively)and molybdenum target X-ray(79.37%and 87.30%,respectively)(P<0.05).The combined methodology specificity(96.83%)did not differ from singlemethod MRI(96.83%)or molybdenum target X-ray(95.24%)(P>0.05).The Twave peak(169.43±32.05)and apparent diffusion coefficient(1.01±0.23)were lower in the breast cancer group than in the benign tumor group(228.86±46.51 and 1.41±0.35,respectively).However,the peak enhancement rate(1.08±0.24)and early enhancement rate(1.07±0.26)were significantly higher in the breast cancer group than in the benign tumor group(0.83±0.19 and 0.75±0.19,respectively)(P<0.05).CONCLUSION Combined molybdenum target X-ray and MRI examinations for diagnosing breast cancer improved the diagnostic sensitivity and accuracy,minimizing the missedand misdiagnoses risks and promoting timely treatment intervention. 展开更多
关键词 MOLYBDENUM x-rays Magnetic resonance imaging Breast neoplasms Early diagnosis RADIOLOGY
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部