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Predictors of Fatal Outcome in Hospitalised Adult Patients with Acute Kidney Injury at Two Tertiary Hospitals in Sub-Saharan Africa
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作者 Denis Georges Teuwafeu Fombo Enjeh Jabbossung +4 位作者 Maimouna Mahamat Eric Aristide Nono Tomta Mbapah Leslie Tasha Francois Kaze Folefack Gloria Ashuntantang 《Open Journal of Nephrology》 2024年第1期86-103,共18页
Introduction: Data on mortality in acute kidney injury (AKI) derives from high-income countries where AKI is hospital-acquired and occurs in elderly patients with a high burden of cardiovascular disease. In sub-Sahara... Introduction: Data on mortality in acute kidney injury (AKI) derives from high-income countries where AKI is hospital-acquired and occurs in elderly patients with a high burden of cardiovascular disease. In sub-Saharan Africa (SSA), AKI is community-acquired occurring in healthy young adults. We aimed to identify predictors of fatal outcomes in patients with AKI in two tertiary hospitals in Cameroon. Methods: Medical records of adults with confirmed AKI, from January 2018 to March 2020 were retrieved. The outcomes of interest were in-hospital deaths and presumed causes of death. We used multiple logistic regressions modeling to identify predictors of death. The study was approved by the ethics boards of both hospitals. Values were considered significant for a p-value of 0.05. Results: We included 285 patient records (37.2% females). The mean (SD) age was 50.1 (19.0) years. Hypertension (n = 97, 34.0%), organ failure (n = 88, 30.9%), and diabetes (n = 60, 21.1%) were the main comorbidities. The majority of patients had community-acquired AKI (78.6%, n = 224), were KDIGO stage 3 (88.8%, n = 253), and needed dialysis (52.6%, n = 150). Up to 16.7% (n = 25) did not receive what was needed. The in-hospital mortality rate was 29.1% (n = 83). Lack of access to dialysis (OR = 27.8;CI: 5.2 - 149.3, p = 0.001), hypotension (OR = 11.8;CI: 1.3 - 24.8;p = 0.001) and ICU admission (OR = 5.7;CI: 1.3 - 24.8, p = 0.001) were predictors of mortality. The presence of co-morbidities or underlying diseases (n = 46, 55%) were the main causes of death. Conclusions: In-hospital AKI mortality is high, as in other low- and middle-income economies. Lack of access to dialysis and the severity of the underlying illness are major predictors of death. 展开更多
关键词 PREDICTORS Fatal Outcome Acute Kidney Injury Tertiary hospital
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Development of Self-Rated Nursing Record Frequency for Delirium Care of Nurses in Acute Care Hospitals (NRDC-Acute)
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作者 Katsuhiko Hattori Kenichi Matsuda 《Open Journal of Nursing》 2024年第8期412-420,共9页
Background: Nursing records play an important role in multidisciplinary collaborations in delirium care. This study aims to develop a self-rated nursing record frequency scale for delirium care among nurses in acute c... Background: Nursing records play an important role in multidisciplinary collaborations in delirium care. This study aims to develop a self-rated nursing record frequency scale for delirium care among nurses in acute care hospitals (NRDC-Acute). Methods: A draft of the scale was developed after a literature review and meeting with researchers with experience in delirium care, and a master’s or doctoral degree in nursing. We identified 25 items on a 5-point Likert scale. Subsequently, an anonymous self-administered questionnaire survey was administered to 520 nurses from 41 acute care hospitals in Japan, and the reliability and validity of the scale were examined. Results: There were 232 (44.6%) respondents and 218 (41.9%) valid responses. The mean duration of clinical experience was 15.2 years (SD = 8.8). Exploratory factor analysis extracted 4 factors and 13 items for this scale. The model fit indices were GFI = 0.991, AGFI = 0.986, and SRMR = 0.046. The Cronbach’s alpha coefficient for the entire scale was .888. The four factors were named “Record of Pharmacological Delirium Care on Pro Re Nata (PRN)”, “Record of Non-Pharmacological Delirium Care”, “Record of Pharmacological Delirium Care on Regular Medication”, and “Record of Collaboration for Delirium Care”. Conclusion: The scale was relatively reliable and valid. Nurses in acute care hospitals can use this scale to identify and address issues related to the documentation of nursing records for delirium care. 展开更多
关键词 Acute Care hospitals Delirium Care Nurses Nursing Records Scale Development
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Hyperprolactinemia in Hospitals in Lomé: Diagnostic and Therapeutic Aspects
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作者 Tchamdja Toyi Djalogue Lihanimpo +6 位作者 Kodjo Kossi Ganu Koudjo Kaaga Laconi Yéba Mossi Komi Edem M’bortché B. Kodjo Djibril Mohaman Awalou Balaka Abago 《Open Journal of Internal Medicine》 2024年第1期43-52,共10页
Introduction. Hyperprolactinemia represents a supraphysiological secretion of prolactin. In clinical practice, it is the most frequently encountered anterior pituitary disorder. However, its real prevalence is little ... Introduction. Hyperprolactinemia represents a supraphysiological secretion of prolactin. In clinical practice, it is the most frequently encountered anterior pituitary disorder. However, its real prevalence is little known in Africa. The purpose of this study is to list all cases of hyperprolactinemia over the past four years and to make an inventory of the various etiologies found and their management. Methodology. This is a cross-sectional descriptive study on the files of patients who came for consultation in the internal medicine and endocrinology department with hyperprolactinemia retrospectively collected from January 2017 to December 2020. Included were patients followed or whose the diagnosis of hyperprolactinemia was established in endocrinological consultation during the study period. Results. This study recorded 26 cases of hyperprolactinemia. The female sex represented 73.08% (sex ratio M/F 0.37) and the average age was 33.92 years. The 40 - 50 age group was the most represented with 30.77%. In women, galactorrhea accounted for 73.07%, amenorrhea 57.69% of clinical pictures and infertility 23.08%. In men, infertility accounted for 7.69% of presentations, gynecomastia 11.54% and erectile dysfunction 15.38%. The duration of evolution of the signs was 4 months in 23.08% of the patients. The mean prolactinemia was 702.58 ng/ml. CT was performed in 80.85% of patients. The main etiologies were pituitary adenomas (77%). All our patients were treated with dopaminergic agonists. Cabergoline was prescribed in 77% of patients. The evolution was favorable in 96.25% of patients. Conclusion. Hyperprolactinemia is a pathology that exists in our regions. The main etiology remains pituitary adenomas and treatment with cabergoline. 展开更多
关键词 HYPERPROLACTINEMIA hospital Environment CHU SO TOGO
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Theoretical Analysis and Practical Reflection on the Role Conflict of Double-Qualified Teachers in University-Affiliated Hospitals
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作者 Yuanyuan Jia Yu Cai +2 位作者 Siqi Wang Ying Yang Ge Wu 《Journal of Contemporary Educational Research》 2024年第5期27-36,共10页
Taking role conflict as the starting point,this article examines and reflects on the development of clinical teachers.In the process of the occurrence,development,and resolution of role conflicts among clinical teache... Taking role conflict as the starting point,this article examines and reflects on the development of clinical teachers.In the process of the occurrence,development,and resolution of role conflicts among clinical teachers,there are many hidden issues related to the development of clinical teachers.The development of clinical teacher teaching and role conflict management contain similar educational philosophies and practical issues.This study draws on classic theories and research achievements in the development of university teachers and conducts theoretical analysis and practical reflection on the development of clinical teachers in medical colleges from the perspective of role conflict in social psychology.Policy recommendations are proposed,including strengthening the construction of teaching systems at the hospital organizational environment level,enhancing the role identity and teacher beliefs of clinical teachers,promoting their teaching development and academic learning,and ensuring their normal teaching investment;promoting leadership support at the level of interpersonal interaction and leveraging the role of colleague support in alleviating role conflicts;enhancing individual teacher beliefs,teacher role learning,and role skills. 展开更多
关键词 University-affiliated hospitals Double-qualified teachers Role conflict
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Management Measures for Preventing Postoperative Incision Infections in General Surgery at Primary Hospitals
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作者 Jianqiang Yang 《Journal of Clinical and Nursing Research》 2024年第8期270-275,共6页
Objective:To analyze the management measures and effects of preventing postoperative incision infections in the general surgery department of primary hospitals.Methods:Forty-nine surgical patients with 11 healthcare w... Objective:To analyze the management measures and effects of preventing postoperative incision infections in the general surgery department of primary hospitals.Methods:Forty-nine surgical patients with 11 healthcare workers who were admitted to the general surgery department of the primary hospital between August 2021 and August 2022 were selected as the routine group for routine incision infection management.Forty-nine surgical patients with 11 healthcare workers admitted to the same department between September 2022 and September 2023 were selected as the prevention group for prophylactic management of postoperative incision infections.The incision infection rate,knowledge,attitude,and practice(KAP)scores,and management satisfaction of the patients as well as the management skill scores of healthcare workers were compared between the two groups.Results:The rate of postoperative incision infection in the prevention group was lower than that in the routine group;after implementing management measures,patients in the prevention group had higher KAP scores than those in the routine group;patients in the prevention group were more satisfied with the management than those in the routine group;and healthcare workers in the prevention group had higher scores than those in the routine group,with P<0.05 for the comparison between the groups.Conclusion:The implementation of preventive management for general surgery patients in primary hospitals can reduce the incidence of postoperative incision infection and improve the KAP of patients,with higher management satisfaction.It can also enhance the management skills of healthcare workers,thus improving their overall management level. 展开更多
关键词 Primary hospital General surgery Postoperative incision infection Management measures
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Exploration of Teaching Development Strategies for Double-Qualified Teachers in University- Affiliated Hospitals Based on Role Conflict Theory
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作者 Yuanyuan Jia Yu Cai +2 位作者 Siqi Wang Ying Yang Ge Wu 《Journal of Contemporary Educational Research》 2024年第6期121-127,共7页
This study draws on the classic theories and research achievements of university teacher development,and from the perspective of role conflict in social psychology,proposes policy recommendations for the development o... This study draws on the classic theories and research achievements of university teacher development,and from the perspective of role conflict in social psychology,proposes policy recommendations for the development of clinical teachers in medical colleges,including following different stages of teacher development and designing teaching development strategies at different levels;designing the content and form of teaching development activities to meet the temporal and spatial needs of clinical teachers;and building an academic community for clinical teachers to promote the creation of teaching development behaviors. 展开更多
关键词 University-affiliated hospitals Double-qualified teachers Role conflict theory Teaching development strategies
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Study on the Changes of Medical Income Structure in Governmentrun Hospitals of Traditional Chinese Medicine from 2012 to 2021
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作者 Song Yamei 《Asian Journal of Social Pharmacy》 2024年第2期178-190,共13页
Objective To study the changing characteristics and trend of medical income structure in the government-run hospitals of traditional Chinese medicine(TCM),evaluate the effects of relevant reform measures,and to put fo... Objective To study the changing characteristics and trend of medical income structure in the government-run hospitals of traditional Chinese medicine(TCM),evaluate the effects of relevant reform measures,and to put forward corresponding suggestions for further optimizing their income structure.Methods The data related to the average medical income of government-run hospitals of TCM from 2012 to 2021 were sorted out.Then,descriptive analysis method was used to analyze the changes of related indicators.Besides,structural change method was applied to investigate the changes of outpatient income and inpatient income.Results and Conclusion From 2012 to 2021,the growth of medical income in government-run hospitals of TCM tended to be stable,and the proportion of medical service income increased from 22.62%(2012)to 29.38%(2021),but the average annual growth rate was only 0.68%.The main items that caused the change of outpatient income structure were medicine revenue,laboratory tests,diagnosis and treatment,and the cumulative contribution rate was 89.15%.The main items that caused the change of inpatient income structure were medicine revenue,sanitary materials,and auxiliary examinations income,with a cumulative contribution rate of 80.04%.However,the contribution rate of registration,diagnosis,treatment,surgery and nursing income reflecting the value of medical personnel’s technical labor was relatively small.The medical income structure of government-run hospitals of TCM underwent great changes and gradually became reasonable,but the medical service income increased slowly,and not all indicators achieved the expectations.To promote the sustainable development of public hospitals of TCM and enable them to provide high-quality and efficient TCM medical and health services,it is necessary to further improve the relevant policy mechanism. 展开更多
关键词 government-run hospitals of traditional Chinese medicine medical expenses structure optimization sustainable development
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Cu、Sn、Ag同位素在古金属制品溯源研究中的应用
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作者 程文斌 郎兴海 +6 位作者 欧阳辉 彭义伟 陈翠华 谢富伟 王勇 彭强 杨超 《地质学报》 EI CAS CSCD 北大核心 2024年第7期2001-2024,共24页
近年来,随着同位素分析方法的不断突破和新一代多接收电感耦合等离子体质谱(MC-ICP-MS)测试技术的广泛应用,Cu、Sn、Ag等非传统同位素在古代金属制品溯源研究中显示出较好的应用前景。本文综述了近20年来Cu、Sn、Ag同位素在古代金属制... 近年来,随着同位素分析方法的不断突破和新一代多接收电感耦合等离子体质谱(MC-ICP-MS)测试技术的广泛应用,Cu、Sn、Ag等非传统同位素在古代金属制品溯源研究中显示出较好的应用前景。本文综述了近20年来Cu、Sn、Ag同位素在古代金属制品应用研究的相关进展,并展望了其应用前景:①由于不同矿床之间Cu、Sn、Ag同位素存较大重叠,这些同位素均难以作为独立的证据追溯金属制品的地质来源;②Cu同位素在原生矿石与表生矿石之间存在较大的分馏,是示踪铜矿石类型的可靠方法,Ag同位素也具推断银矿石类型的潜力;③将Cu、Sn、Ag同位素与Pb同位素、微量元素相结合,并采用合理的统计方法,开展综合溯源研究将是今后应用非传统同位素进行古代金属制品溯源研究的发展方向。 展开更多
关键词 Cu同位素 sn同位素 Ag同位素 古代金属制品 溯源研究
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铸态下Sn-Bi二元共晶焊料合金的组织特征及其力学性能
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作者 唐玲 张会 +1 位作者 孟凡莹 刘艳 《有色金属工程》 CAS 北大核心 2024年第7期52-59,共8页
研究了四种不同Bi含量(45%、50%、55%、60%)的Sn-Bi二元共晶合金自由凝固下的组织特征和力学性能,探讨了Sn-Bi二元共晶合金的晶体生长机制以及Bi元素含量对合金显微组织的影响。结果表明:Sn-Bi二元亚共晶合金铸态下的金相组织为初生Sn... 研究了四种不同Bi含量(45%、50%、55%、60%)的Sn-Bi二元共晶合金自由凝固下的组织特征和力学性能,探讨了Sn-Bi二元共晶合金的晶体生长机制以及Bi元素含量对合金显微组织的影响。结果表明:Sn-Bi二元亚共晶合金铸态下的金相组织为初生Sn固溶体相和Sn/Bi共晶层片集群构成,随着Bi含量的增加,呈树枝晶形态生长的初生Sn相数量减少,形态长大。初生Sn固溶体相内部脱溶析出大量的杆状或点状Bi相,形成杆状共晶结构;Sn-Bi二元过共晶合金铸态下的金相组织为初生Bi相和Sn/Bi共晶层片集群构成,初生Bi相中基本不固溶Sn元素,呈小平面方式生长,并在在初生Bi相周围包裹生长一层Sn晕圈相。在室温下,Sn-Bi二元共晶合金的硬度和强度随着Bi含量的增加而上升,延伸率随着Bi含量的增加先上升后下降。 展开更多
关键词 sn-Bi二元共晶合金 杆状共晶 晕圈相 显微组织 力学性能
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单层SnS的光电效应及应变工程的第一性原理研究
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作者 徐中辉 许晟源 +1 位作者 刘川川 刘国港 《人工晶体学报》 CAS 北大核心 2024年第4期676-683,共8页
光电探测器在工业制造和军事国防等各领域用途广泛。近年来,研究者在寻找一种兼具极化灵敏度高与光响应强的特点的光电探测器。在可见光范围内,SnS是一种制作具有各向异性光电探测器的半导体材料。本文基于第一性原理,采用非平衡态格林... 光电探测器在工业制造和军事国防等各领域用途广泛。近年来,研究者在寻找一种兼具极化灵敏度高与光响应强的特点的光电探测器。在可见光范围内,SnS是一种制作具有各向异性光电探测器的半导体材料。本文基于第一性原理,采用非平衡态格林函数(NEGF)与密度泛函理论(DFT)结合的方法对单层SnS两个器件方向(Armchair和Zigzag)的光电性质进行理论计算。研究发现,在零偏压下,两个方向的光电流数值均较小,通过加偏压的方法可以获得稳定的光电流。计算了小偏压0.1~1.0 V(间隔0.1 V)、线性偏振光照射下最大光响应随光子能量的变化,发现单层SnS在光子能量为2.4与3.2 V时最大光响应数值较大且十分稳定,并结合能带图和态密度图分析了光响应产生的微观机制。本文通过计算消光比,发现单层SnS具有极强的偏振灵敏度。最后,通过施加双轴应变的方法,器件的不对称性显著增加,极大增强器件在零偏压下的光电流,其中压缩应力数值为-6%时对光电流的提升十分明显。希望以上结果能为单层SnS设计用于光电探测器提供理论参考。 展开更多
关键词 单层snS 光电探测器 第一性原理 最大光响应 偏振灵敏度 应变工程
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生物可降解挤压态Mg-Sn-Zn-Zr合金组织与腐蚀性能的研究 被引量:1
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作者 刘德学 张全发 +1 位作者 郭菲菲 周田水 《热加工工艺》 北大核心 2024年第15期94-99,共6页
采用气体保护法制备了高强塑性Mg-Sn-Zn-Zr(TZK)合金,然后在不同温度(300、350、400℃)对其进行挤压变形,并对合金的微观组织、物相组成和体外降解行为进行研究。结果表明:300℃挤压后合金的组织为均匀细小的等轴晶,晶粒尺寸最小,为6.57... 采用气体保护法制备了高强塑性Mg-Sn-Zn-Zr(TZK)合金,然后在不同温度(300、350、400℃)对其进行挤压变形,并对合金的微观组织、物相组成和体外降解行为进行研究。结果表明:300℃挤压后合金的组织为均匀细小的等轴晶,晶粒尺寸最小,为6.57μm;析氢量和腐蚀速率最低,耐腐蚀性能最好。随挤压温度升高,合金的晶粒长大,组织中出现孪晶,导致其耐腐蚀性能变差。 展开更多
关键词 Mg-sn-Zn-Zr合金 挤压变形 微观组织 腐蚀性能
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C/Sn复合薄膜的磁控溅射制备及其作为锂离子电池负极材料的电化学性能
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作者 闫共芹 时孟杰 +2 位作者 王欣琳 蓝春波 武桐 《微纳电子技术》 CAS 2024年第2期78-86,共9页
采用磁控溅射的方法在铜箔上制备了C/Sn复合薄膜并将其作为锂离子电池负极材料,研究了C/Sn复合薄膜中Sn质量分数对其电化学性能的影响。研究发现,随着复合薄膜中Sn质量分数的增加,其首圈放电比容量增加,在一定范围内增加Sn质量分数,首... 采用磁控溅射的方法在铜箔上制备了C/Sn复合薄膜并将其作为锂离子电池负极材料,研究了C/Sn复合薄膜中Sn质量分数对其电化学性能的影响。研究发现,随着复合薄膜中Sn质量分数的增加,其首圈放电比容量增加,在一定范围内增加Sn质量分数,首圈库仑效率增加,但当Sn质量分数过多时其库仑效率降低。Sn质量分数分别为89.20%、91.61%、93.85%、95.81%的四种复合薄膜,在电流密度为500 mA/g时的首圈放电比容量分别为1195.4、1372.97、1574.86、1642.30 mA·h/g,首圈库仑效率分别为86.84%、87.88%、94.06%、80.66%。循环200圈后,四种复合薄膜的比容量衰减率分别为0.70%、6.13%、11.32%、18.88%。研究结果表明,当复合薄膜中Sn质量分数为89.20%时,其具有最优的倍率性能和循环稳定性能,随着复合薄膜中Sn质量分数的增加,其倍率性能及循环稳定性变差。 展开更多
关键词 锂离子电池 负极材料 磁控溅射 C/sn复合薄膜 电化学性能 循环稳定性
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通过不同热挤压方式制备具有较优强塑性组合的新型Mg-5Sn-2Al-1Zn合金
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作者 石凤健 朴南瑛 +6 位作者 王冀恒 谭昊天 郭宇航 杨飞 陈书锦 芦笙 王泽鑫 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第7期2120-2137,共18页
制备新型Mg-5Sn-2Al-1Zn(TAZ521)合金。为提高合金的强度与塑性,采用正挤压(DE)和挤压-剪切(ES)两种工艺对该合金进行变形处理。通过XRD、SEM、TEM、EBSD和拉伸试验等方法研究均匀态和挤压态合金的显微组织演变、织构演变及强化机制。... 制备新型Mg-5Sn-2Al-1Zn(TAZ521)合金。为提高合金的强度与塑性,采用正挤压(DE)和挤压-剪切(ES)两种工艺对该合金进行变形处理。通过XRD、SEM、TEM、EBSD和拉伸试验等方法研究均匀态和挤压态合金的显微组织演变、织构演变及强化机制。结果表明,正挤压态合金的力学性能得到改善;然而,合金表现出由粗晶和细小动态再结晶(DRXed)晶粒组成的双峰组织。经过挤压-剪切变形后的合金组织变得更加均匀,并且实现更好的强韧性结合,变形后合金的屈服强度(YS)、极限抗拉强度(UTS)和伸长率(EL)分别达到212 MPa、303 MPa和21.7%。晶粒细化和Mg2Sn析出物的钉扎效应对强度的提高起到重要作用,此外,延展性的提高归因于基面纤维织构的弱化和非基面滑移系的激活。 展开更多
关键词 Mg-sn-Al-Zn合金 挤压-剪切 晶粒细化 力学性能 织构演变
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Si调控Cu-20Sn-15Ti钎料显微组织与性能的演变行为
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作者 张黎燕 杜全斌 +5 位作者 毛望军 崔冰 李昂 王蕾 纠永涛 梁杰 《金刚石与磨料磨具工程》 CAS 北大核心 2024年第3期309-318,共10页
为通过成分调控改善Cu-Sn-Ti钎料的显微组织及性能,采用扫描电子显微镜、X射线衍射仪及EDS能谱分析等设备,研究了Si对Cu-20Sn-15Ti钎料显微组织与性能的影响规律。结果表明:Cu-20Sn-15Ti钎料的显微组织为大尺寸多边形状CuSn_(3)Ti_(5)... 为通过成分调控改善Cu-Sn-Ti钎料的显微组织及性能,采用扫描电子显微镜、X射线衍射仪及EDS能谱分析等设备,研究了Si对Cu-20Sn-15Ti钎料显微组织与性能的影响规律。结果表明:Cu-20Sn-15Ti钎料的显微组织为大尺寸多边形状CuSn_(3)Ti_(5)相、共晶组织和α-Cu相。添加少量的Si(质量分数≤2.0%)可细化钎料中多边形状CuSn_(3)Ti_(5)相,并生成小尺寸Si_(3)Ti_(5)相,较多的Si(质量分数≥3.0%)会造成多边形状CuSn_(3)Ti_(5)相分化离散、共晶组织粗化减少,Si_(3)Ti_(5)相含量增加且粗化,当Si含量增至5.0%时,钎料不再生成多边形状CuSn_(3)Ti_(5)相和共晶组织,Ti主要用于生成Ti_(5)Si_(3)相,显微组织主要为Ti_(5)Si_(3)相、α-Cu相、Cu41Sn11相和少量条状CuSn_(3)Ti_(5)相;与Cu、Sn相比,Si与Ti具有更强的化学亲和力,Si优先与Ti反应生成Ti_(5)Si_(3)相;Ti_(5)Si_(3)相的三维组织形貌为棱柱状,且呈团聚附生特征,粗条状Ti_(5)Si_(3)相具有中心或侧面孔洞缺陷,孔洞的形成主要与其生长机制有关;随着Si含量的增加,钎料的剪切强度呈“升高-降低-升高”的趋势,断口形貌由准解理断裂和解理断裂的混合形态向解理断裂转变;CuSn_(3)Ti_(5)相易破碎开裂成为起裂源,不同粗大状态CuSn_(3)Ti_(5)相的存在均在一定程度上恶化钎料剪切强度。 展开更多
关键词 Cu-sn-Ti钎料 金刚石 显微组织 Cusn_(3)Ti_(5)相
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轧制态TiZrNbSn合金的再结晶行为
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作者 炊鹏飞 程尊鹏 +4 位作者 李春梅 王晶 何逸哲 景然 李江华 《材料热处理学报》 CAS CSCD 北大核心 2024年第8期204-212,共9页
首先对冷轧态Ti-49Zr-21Nb-1.0Sn(TZNS1.0)合金分别在600、650、700、750、800和850℃进行再结晶退火处理10、20、30、60、90和120 min,随后采用光学显微镜(OM)和电子背散射衍射(EBSD)技术分析了热处理后合金的组织演变,计算了合金的再... 首先对冷轧态Ti-49Zr-21Nb-1.0Sn(TZNS1.0)合金分别在600、650、700、750、800和850℃进行再结晶退火处理10、20、30、60、90和120 min,随后采用光学显微镜(OM)和电子背散射衍射(EBSD)技术分析了热处理后合金的组织演变,计算了合金的再结晶激活能,建立了其再结晶动力学模型。结果表明:随着退火温度的升高,TZNS1.0合金的再结晶形核孕育时间缩短,β晶粒经历了回复、再结晶形核和长大阶段。随着退火时间的增加,合金的晶粒尺寸增大,但长大速度逐渐减小。TZNS1.0合金在750℃再结晶退火后,仅少数区域发生再结晶,大部分区域仍为变形组织,并存在许多小角度晶界、高密度位错和轧制织构。在800℃退火后,再结晶区域呈现大角度晶界,轧制织构和高密度位错被消除。退火温度进一步升高到850℃时,再结晶过程全部完成,合金晶粒明显长大。TZNS1.0合金的再结晶激活能为67.45 kJ/mol,850℃退火处理时,合金的再结晶动力学方程为x=1-e^(-0.05t 0.9)。 展开更多
关键词 Ti-Zr-Nb-sn合金 再结晶退火处理 显微组织 再结晶行为
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Sn-Zn合金包覆PAN基碳纤维/聚六氟丙烯有机光纤材料的制备
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作者 孔德忠 周浩然 《合成树脂及塑料》 CAS 北大核心 2024年第2期38-41,共4页
采用Sn-Zn合金包覆聚丙烯腈(PAN)基碳纤维,以聚六氟丙烯为载体制备塑料光纤(POF)皮层材料,并将POF皮层材料与聚苯乙烯光纤芯材进行匹配,研究了材料在力学性能、传输损耗性、光场强度方面的变化。结果表明:Sn-Zn合金表面包覆PAN基碳纤维... 采用Sn-Zn合金包覆聚丙烯腈(PAN)基碳纤维,以聚六氟丙烯为载体制备塑料光纤(POF)皮层材料,并将POF皮层材料与聚苯乙烯光纤芯材进行匹配,研究了材料在力学性能、传输损耗性、光场强度方面的变化。结果表明:Sn-Zn合金表面包覆PAN基碳纤维与聚六氟丙烯结合紧密,作为POF皮层材料的效果良好,在最常见的650 nm波长、100 m内,传输低于100 Mb/s速率数据信息的能力符合要求,光信号基本环绕着光纤芯材传播,没有过多的光信号因为皮层材质的缘故而散失,表明该皮层材料与聚苯乙烯光纤芯材的匹配性较高。 展开更多
关键词 sn-Zn合金 聚丙烯腈基碳纤维 聚六氟丙烯 塑料光纤皮层材料 传输损耗
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Al-Sn复合材料的制备及其水反应产氢效率
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作者 刘建新 肖飞 《石油化工》 CAS CSCD 北大核心 2024年第2期161-166,共6页
为提高Al和水的反应活性,采用高能球磨法制备了Al-Sn复合材料,通过SEM、激光粒径分析、XRD等方法表征了Al-Sn复合物的微观结构,研究了Al-Sn复合材料的水反应活性,考察了颗粒粒径、水介质、起始温度、球磨参数变化对Al-Sn复合物水反应活... 为提高Al和水的反应活性,采用高能球磨法制备了Al-Sn复合材料,通过SEM、激光粒径分析、XRD等方法表征了Al-Sn复合物的微观结构,研究了Al-Sn复合材料的水反应活性,考察了颗粒粒径、水介质、起始温度、球磨参数变化对Al-Sn复合物水反应活性的影响。实验结果表明,高能球磨法及金属Sn的加入能够大幅提高Al与水反应的活性,制备的Al-Sn复合材料与水反应的氢气产率达83.92%,快速期最大产氢速率为359mL/(min·g)。 展开更多
关键词 Al-sn复合材料 高能球磨 水反应活性 产氢效率
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Mg_(8)Sn_(4-x)M_(x)结构稳定性与弹性常数的第一性原理计算 被引量:1
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作者 邢旭 尹成斌 +1 位作者 马贝贝 王远 《原子与分子物理学报》 CAS 北大核心 2024年第2期151-156,共6页
利用基于密度泛函理论的CASTEP软件构建Mg_(8)Sn_(4-x)M_(x)(M=Al、Cu;x=0、1或2)晶体结构模型,采用第一性原理计算其晶格常数、结构稳定性和弹性常数,并分析不同量的M原子固溶于Mg_(2)Sn后体系的电子特性、弹性性能和本征硬度.计算结... 利用基于密度泛函理论的CASTEP软件构建Mg_(8)Sn_(4-x)M_(x)(M=Al、Cu;x=0、1或2)晶体结构模型,采用第一性原理计算其晶格常数、结构稳定性和弹性常数,并分析不同量的M原子固溶于Mg_(2)Sn后体系的电子特性、弹性性能和本征硬度.计算结果表明,M原子能自发固溶于Mg_(2)Sn相,且所得Mg_(8)Sn_(4-x)M_(x)(x=1或2)晶体结构均可稳定存在;当2个M原子固溶于Mg_(2)Sn时,使其晶体结构由立方晶系转变为四方晶系.态密度分析表明,M原子固溶后体系原子存在明显轨道杂化现象,表现出较强的共价键,增加M原子固溶量不会改变各原子对态密度的贡献规律,但会提高该原子对电子对态密度的贡献度.弹性性能和本征硬度分析表明:Mg_(2)Sn中固溶M原子后,体系力学性能仍稳定,增加M原子固溶量,体系硬度逐渐降低,韧塑性不断提高,即M原子固溶量增加能提升体系的韧塑性. 展开更多
关键词 Mg_(2)sn 第一性原理 电子结构 弹性常数 本征硬度
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赣北彭山还原性S型花岗岩成因及其对Sn富集的启示:来自锆石微量元素的证据
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作者 尹青青 唐菊兴 +8 位作者 项新葵 赵晓彦 汪方跃 徐裕敏 郭虎 余振东 谢金玲 代晶晶 彭勃 《地学前缘》 EI CAS CSCD 北大核心 2024年第3期133-149,共17页
彭山锡多金属矿集区成矿区划位于长江中下游成矿带与江南钨多金属成矿带的过渡部位。以前研究认为与锡大规模成矿有关的花岗岩通常为高分异的过铝质岩浆,但是关于Sn在还原性岩浆中与矿物相的分配和迁移的氧逸度阈值犹未可知,锡与钨在赣... 彭山锡多金属矿集区成矿区划位于长江中下游成矿带与江南钨多金属成矿带的过渡部位。以前研究认为与锡大规模成矿有关的花岗岩通常为高分异的过铝质岩浆,但是关于Sn在还原性岩浆中与矿物相的分配和迁移的氧逸度阈值犹未可知,锡与钨在赣北地区成矿的分带分区(解耦)究竟是受岩浆源区特征的控制还是为氧逸度所制约,目前尚不清楚。本文对区内花岗岩岩石成因、锡的来源、岩浆演化早期的氧化还原条件,及其对锡在岩浆中的分配、萃取和迁移的控制过程开展了研究,即对彭山岩体进行了精细的锆石原位微区分析测试。结果显示,锆石P含量普遍较高,结合P(∑REE+Y)拟合的3条趋势线的斜率分别为0.91、0.85和0.81,与S型花岗岩(∑REE+Y)<1.15×P演变规律相符。在Eu/Eu^(*)Yb N/Gd N关系图解中未显示出与Ti分离曲线的同步协变关系,相反,各组岩石均显示为负相关关系,说明3组锆石Eu/Eu^(*)的比值受榍石与斜长石的共结晶的影响较为有限。依据Hf Ce^(4+)/Ce^(3+)zircon和Ti Ce^(4+)/Ce^(3+)zircon关系图,白云母花岗岩数据区域均位于趋势线末端,与黑云母二长花岗岩和花岗斑岩相比,显示出更低的氧逸度特点。Eu/Eu^(*)与Ce^(4+)/Ce^(3+)zircon比值在各岩石单元中所表现出的还原程度是相耦合的,即组成彭山岩体的3个岩石单元——成矿后花岗斑岩岩脉、黑云母二长花岗岩岩基和白云母花岗岩成矿岩株,其锆石Eu异常(Eu/Eu^(*))和Ce^(4+)与Ce^(3+)比值(Ce^(4+)/Ce^(3+)zircon)呈逐渐递减趋势。双桥山群中1.5~1.3 Ga砂泥质沉积岩与细碧角斑岩系组成的海相古火山喷发沉积建造,可能提供了本区Sn的初始来源。白云母花岗岩成矿岩株的氧逸度显著低于大湖塘石门寺矿床的花岗岩,锆石微量元素揭示了富锡岩浆演化比富钨岩浆具有更低的氧逸度。 展开更多
关键词 还原性 S型花岗岩 sn富集 锆石 赣北 彭山
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Research misconduct in hospitals is spreading:A bibliometric analysis of retracted papers from Chinese university-affiliated hospitals 被引量:2
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作者 Zi-han Yuan Yi Liu 《Journal of Data and Information Science》 CSCD 2023年第4期84-101,共18页
Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated ho... Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated hospitals in China’s mainland from 2000 to 2021. Design/methodology/approach: Data for 1,031 retracted papers were identified from the Web of Science Core collection database. The information of the hospitals involved was obtained from their official websites. We analyzed the chronological changes, journal distribution, discipline distribution and retraction reasons for the retracted papers. The grade and geographic locations of the hospitals involved were explored as well.Findings: We found a rapid increase in the number of retracted papers, while the retraction time interval is decreasing. The main reasons for retraction are plagiarism/self-plagiarism(n=255), invalid data/images/conclusions(n=212), fake peer review(n=175) and honesty error(n=163). The disciplines are mainly distributed in oncology(n=320), pharmacology & pharmacy(n=198) and research & experimental medicine(n=166). About 43.8% of the retracted papers were from hospitals affiliated with prestigious universities. Research limitations: This study fails to differentiate between retractions due to honest error and retractions due to research misconduct. We believe that there is a fundamental difference between honest error retractions and misconduct retractions. Another limitation is that authors of the retracted papers have not been analyzed in this study.Practical implications: This study provides a reference for addressing research misconduct in Chinese university-affiliated hospitals. It is our recommendation that universities and hospitals should educate all their staff about the basic norms of research integrity, punish authors of scientific misconduct retracted papers, and reform the unreasonable evaluation system.Originality/value: Based on the analysis of retracted papers, this study further analyzes the characteristics of institutions of retracted papers, which may deepen the research on retracted papers and provide a new perspective to understand the retraction phenomenon. 展开更多
关键词 Retracted papers RETRACTION Research integrity Research misconduct Chinese university-affiliated hospitals
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