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Effect of furnace atmosphere on sintering process of chromium-containing steel via powder metallurgy

Journal of Iron and Steel Research International 2021年第7期28卷 889-900页

作者： zhao-qiang Tan Ulf EngstrÖm Kun Li yong Liu State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083HunanChina HÖganäs China Co. Ltd.Shanghai 201799China

During a powder metallurgy process such as sintering,the primary role played by the atmosphere in furnace is to prevent an excessive oxidation of powder compacts in case of the formation of oxides as residuals on powder *** particular,the adjustment of furnace atmosphere is the key to eliminate the phenomenon"decarburization"likely to occur in carbon-containing compacts.A continuous belt furnace was used to stabilize the potentials of carbon and oxygen in zones divided by sintering,delubrication,and *** and manganese,which are sensitive to oxygen,were added to improve mechanical properties in a cost-effective *** of steel containing chromium were sintered in an atmosphere composed of CO,O_(2),and H_(2).The effects of atmosphere,lubricant,and graphite on oxidation(or reduction)and decarburization(or carburization)were *** quality was achieved under the control of delubrication *** is indicated that in a protective atmosphere,the chemical reactions occurring at various stages took remarkable effect on the quality of sintered *** potentials of oxygen and carbon in a continuous belt furnace were monitored and analyzed using an on-line thermal measuring unit consisting of thermocouple,oxygen probe,and carbon monoxide *** avoidance of oxidation and decarburization promises desired micro structure and carbon content and satisfactory properties through the adjustment of technical parameters,e.g.,the composition of gases in delubrication and various sintering zones,the rate of gas inlet,and cooling rate.

关键词： Powder metallurgy steel Sintering atmosphere Carbon potential Oxygen partial pressure Chromium alloy

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Preparation of Flower-like Copper Foam Supported Co_(3)O_(4) Electrocatalyst and Its Hydrogen Evolution Performance

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 327-331页

作者：李兆 CHENG Julong WANG Yanan WU Kunyao CAO Jing School of Materials Engineering Xi’an Aeronautical InstituteXian 710077China

Flower-like copper foam Co_(3)O_(4) catalysts(Co_(3)O_(4)/CF) were prepared by hydrothermal *** crystalline structure and microscopic morphology of the prepared samples were characterized by using X-ray diffractometer(XRD) and scanning electron microscope(SEM),and the electrochemical properties were investigated by an electrochemical *** experimental results show that the Co_(3)O_(4) catalysts are successfully prepared on the foamed copper support by hydrothermal method,and the material’s morphology is mainly flower *** the current density is 10 mA·cm^(-2),the overpotential value of the Co_(3)O_(4)/CF catalyst is 141 mV,lower than that of blank *** electrochemical impedance(EIS) spectrum shows that the R_(ct )value of the Co_(3)O_(4)/CF catalyst decreases,and the Coulomb curves of double-layer show that the electrochemically active area of the Co_(3)O_(4)/CF catalyst efficiently increases compared with that of the blank ***,the as-obtained Co_(3)O_(4)/CF catalyst exhibits a good hydrogen evolution rate,showing great applicability potential in the catalytic electrolysis of water for hydrogen production.

关键词： Co_(3)O_(4)/CF composite structure electrocatalysis hydrogen evolution reaction

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Cryogenian and Ediacaran integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China Earth Sciences 2024年第4期67卷 919-949页

作者： Lang SUN Malik Muhammad Saud Sajid KHAN Chuan YANG Zhixin SUN Bing PAN Shehryar AHMED Lanyun MIAO Weichen SUN Chunlin HU Xiaojuan SUN Cui LUO Bo CHEN Zongjun YIN Fangchen zhao Guoxiang LI Maoyan ZHU State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The complex evolutionary history of the Qinghai-Tibetan Plateau and its surrounding areas,including the continental blocks(Indian,Lhasa,South Qiangtang,Tarim,Olongbuluk,Central Qilian,Alxa,North China,Yangtze,Central Iran and Oman)and the orogenic belts between them,has long been the frontier in Earth science *** Cryogenian and Ediacaran strata are extensively distributed in these ***,relatively complete Cryogenian and Ediacaran successions have been discovered in Oman,Indian,Yangtze,and Tarim blocks,while only the Ediacaran successions have been reported in Iran,the South Qiangtang,Central Qilian,Alxa,and North China *** on previous studies together with the integration of new materials and advancement obtained through the Second Tibetan Plateau Scientific Expedition and Research,this review aims to synthesize a correlative stratigraphic framework of the representative Cryogenian and Ediacaran sequences from the Qinghai-Tibetan Plateau and its surrounding ***,the Cryogenian and Ediacaran biotas and major geological events in these areas are comprehensively discussed in aspects of current research *** results indicate that,in general,Ediacaran fossils of each area exhibit distinct features in preservation and assemblage composition,but the typical late Ediacaran fossils Cloudina and Shaanxilithes have been reported from most of these *** addition to the two global Cryogenian glaciations,late Ediacaran glaciogenic deposits are extensively recorded in the areas within and around the northern QinghaiTibetan Plateau(including the North China,Alxa,Central Qilian,Olongbuluk,and Tarim blocks,and the North Qilian Accretionary Belt),as well as central and southern ***,further research is required to determine the age,distribution,and origin of these late Ediacaran glaciogenic ***,the middle Ediacaran DOUNCE/Shuram Excursion is widely documented in the Qinghai-Tibetan Plateau and its surroundi

关键词： Qinghai-Tibetan Plateau Cryogenian Ediacaran Stratigraphy Palaeogeography Biota Gondwana

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快速城市化进程下西安市水网格局演变特征研究

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水资源与水工程学报 2024年第2期35卷 91-98页

作者：谢跃姜仁贵解建仓赵勇李发文朱记伟西安理工大学西北旱区生态水利国家重点实验室陕西西安710048 中国水利水电科学研究院流域水循环模拟与调控国家重点实验室北京100038 天津大学水利工程仿真与安全国家重点实验室天津300072

为揭示城市化对水网的影响,科学规划水网布局,以国家中心城市西安市为研究区域,基于2000、2010和2020年3期遥感影像和水网数据,从水网数量和结构特征两个方面剖析2000—2020年快速城市化进程下城市水网格局时空演变特征,揭示城市化水平... 详细信息

为揭示城市化对水网的影响,科学规划水网布局,以国家中心城市西安市为研究区域,基于2000、2010和2020年3期遥感影像和水网数据,从水网数量和结构特征两个方面剖析2000—2020年快速城市化进程下城市水网格局时空演变特征,揭示城市化水平与水网特征之间的定量关系。结果表明:2000—2020年建设用地面积不断增加,2020年占到西安市总面积的比重达13.25%,城市化进程由加速发展阶段转变为成熟阶段;西安市水网数量特征呈现持续降低趋势,河网密度和水面率分别衰减了26.47%和20.69%,河流发育系数、河网复杂度等水网结构特征呈现“先增后减,总体衰减”的趋势,衰减率分别为19.87%和17.01%。水网格局根据城市化率不同空间分布差异显著,在自然因素和人类活动共同作用下,西安市整体河网结构稳定度趋于1,水网发育较为稳定;水网格局变化受城市化影响较大,其中,河网复杂度与水面率受城市化的影响大于其对河网密度和河流发育系数的影响。

关键词：水网结构时空演变水网特征参数土地利用/覆被变化西安市

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基于注入锁定技术的单频连续高功率1342 nm Nd:YVO_(4)激光器

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红外与激光工程 2024年第1期53卷 114-120页

作者：周子涵王志敏薄勇张丰丰赵文成付莉何汉星崔大复彭钦军中国科学院理化技术研究所固体激光重点实验室北京100190 中国科学院理化技术研究所功能晶体和激光技术重点实验室北京100190 中国科学院大学北京100049

研究了一种基于注入锁定技术的888 nm半导体激光器(LD)泵浦的高功率单频可调谐1 342 nm Nd:YVO_(4)激光器。采用最大输出功率20 mW分布式反馈单频半导体1 342 nm激光器作为注入种子,利用lock-in (LI)技术,对LD端泵的Nd:YVO_(4)环形腔激... 详细信息

研究了一种基于注入锁定技术的888 nm半导体激光器(LD)泵浦的高功率单频可调谐1 342 nm Nd:YVO_(4)激光器。采用最大输出功率20 mW分布式反馈单频半导体1 342 nm激光器作为注入种子,利用lock-in (LI)技术,对LD端泵的Nd:YVO_(4)环形腔激光器进行种子注入,实现了单频可调谐激光输出。激光器最大平均输出功率为13.9 W,测量的线宽为41 MHz,调谐范围为1 341.677 4~1 341.802 5 nm。x轴和y轴的光束质量M2因子分别为M_(x)^(2)=1.30和M_(y)^(2)=1.23。实验结果表明:与先前文献报道的注入锁定1 342 nm可调谐激光的结果相比,所需种子功率大幅减小,输出功率也有所提升。

关键词： Nd:YVO_(4)激光器连续波单频可调谐注入锁定

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科研人员的社会资本与职业倦怠

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浙江社会科学 2024年第4期 68-79,157页

作者：赵延东赵智渊石长慧中国人民大学社会学理论与方法研究中心北京100872 中国人民大学社会与人口学院北京100872 中国科学技术发展战略研究院

研究利用一项关于全国科技工作者心理健康状况的调查数据,分析我国科研人员的职业倦怠现状以及社会资本对于职业倦怠的缓解机制。研究发现科研人员的社会网络规模、社会网络密度和社会网络差异性等社会资本特征对缓解其职业倦怠水平有... 详细信息

研究利用一项关于全国科技工作者心理健康状况的调查数据,分析我国科研人员的职业倦怠现状以及社会资本对于职业倦怠的缓解机制。研究发现科研人员的社会网络规模、社会网络密度和社会网络差异性等社会资本特征对缓解其职业倦怠水平有一定作用。进一步的分析表明:紧密的强关系网络有助于形成良好的组织人际氛围,并在负面事件来临时提供社会支持,从而降低科研人员职业倦怠水平;而松散且广泛的社会网络可以促进科研人员的学术交流和资源获取,提高学术绩效,也可起到缓解职业倦怠的作用。本文将社会资本视角引入职业倦怠研究,拓展了对职业倦怠影响因素的理论认识,同时也为缓解科研人员职业倦怠,提升科研人员创新效率提供了政策参考。

关键词：科研人员社会资本职业倦怠社会网络

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Exploring the material basis and mechanism of Moringa oleifera in alleviating slow transit constipation based on network pharmacology and animal models

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Food Science and Human Wellness 2024年

作者： Sijin Li Xiaoyu Gao Kaifeng Guo Shuangfeng Liu Weiqian Yang Yan zhao Jun Sheng Zhongbin Bai Yang Tian College of Food Science and Technology， Yunnan Agricultural University Yunnan Key Laboratory of Precision Nutrition and Personalized Food Manufacturing， Yunnan Agricultural University Department of Science and Technology， Yunnan Agricultural University College of Veterinary Medicine， Yunnan Agricultural University Engineering Research Center of Development and Utilization of Food and Drug Homologous Resources， Ministry of Education， Yunnan Agricultural University

Moringa oleifera(M. oleifera) have laxative effects， but their active compositions and mechanisms are not very clear thus far. To this end， we systematically explored the active components and mechanism of M. oleifera leaves in relieving constipation by using the slow transit constipation (STC) mouse model and network pharmacology. The results of animal experiments showed that M. oleifera aqueous extract (MOA) had good laxative activity， and its 70% alcohol soluble part (ASP) also showed significant laxative activity(P < 0.01). Network pharmacological prediction results suggested that L-phenylalanine (Phe) was the key compound of ASP， and it might relieve constipation through tachykinin receptor 1 (TACR1) and three kinds of adrenergic receptors， including alpha-1a (ADRA1A)， alpha-2a (ADRA2A)， and alpha-2b (ADRA2B). Further animal experiment results showed that Phe significantly promoted gastrointestinal motility. Phe may relieve STC by enhancing the release of substance P (SP) and upregulating the mRNA expression of TACR1 in the ileum. Importantly， Phe may also promote intestinal movement by downregulating ADRA2A and ADRA2B and upregulating calmodulin and the mRNA and protein expression of myosin light chain 9 (MYL9) in the ileum， thereby activating the GPCR-MLC signaling pathway. These results lay a foundation for the application of M. oleifera and Phe in constipation.

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A robust QRS detection and accurate R-peak identification algorithm for wearable ECG sensors

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Science China(Information Sciences) 2021年第8期64卷 213-229页

作者： Kai zhao yongfu LI Guoxing WANG Yu PU yong LIAN Department of Micro and Nano Electronics Shanghai Jiao Tong University Alibaba Group

This paper presents a robust QRS detection algorithm that is capable of detecting QRS complexes as well as accurately identifying R-peaks. The proposed bilateral threshold scheme combined with QRS watchdog greatly improves the detection accuracy and robustness, resulting in consistent detection performance on 9 available ECG databases. Simulations show that the proposed algorithm achieves good results on the datasets from both QTDB healthy database and MITDB arrhythmia database, i.e. the sensitivity of99.99% and 99.88%, the precision of 99.98% and 99.88%, and the detection error rate of 0.04% and 0.31%,respectively. Furthermore, it also outperforms many existing algorithms on six other ECG databases, such as NSTDB, TWADB, STDB, SVDB, AFTDB, and FANTASIADB.

关键词： signal processing QRS detection R-peak detection wearable ECG sensors bilateral threshold

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Risk factors associated with intraoperative persistent hypotension in pancreaticoduodenectomy

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World Journal of Gastrointestinal Surgery 2024年第6期16卷 1582-1591页

作者： Xing-Jun Wang Xi-Chen Xuan zhao-Chu Sun Shi Shen Fan Yu Na-Na Li Xue-Chun Chu Hui Yin You-Li Hu Department of Anesthesia and Perioperative Medicine The First Affiliated Hospital of Nanjing Medical UniversityNanjing 210029Jiangsu ProvinceChina

BACKGROUND Intraoperative persistent hypotension(IPH)during pancreaticoduodenectomy(PD)is linked to adverse postoperative outcomes,yet its risk factors remain *** To clarify the risk factors associated with IPH during PD,ensuring patient safety in the perioperative *** A retrospective analysis of patient records from January 2018 to December 2022 at the First Affiliated Hospital of Nanjing Medical University identified factors associated with IPH in *** factors included age,gender,body mass index,American Society of Anesthesiologists classification,comorbidities,medication history,operation duration,fluid balance,blood loss,urine output,and blood gas *** was defined as sustained mean arterial pressure30 min despite additional deoxyepinephrine and fluid *** Among 1596 PD patients,661(41.42%)experienced *** logistic regression identified key risk factors:increased age[odds ratio(OR):1.20 per decade,95%confidence interval(CI):1.08-1.33](P<0.001),longer surgery duration(OR:1.15 per additional hour,95%CI:1.05-1.26)(P<0.01),and greater blood loss(OR:1.18 per 250-mL increment,95%CI:1.06-1.32)(P<0.01).A novel finding was the association of arterial blood Ca^(2+)<1.05 mmol/L with IPH(OR:2.03,95%CI:1.65-2.50)(P<0.001).CONCLUSION IPH during PD is independently associated with older age,prolonged surgery,increased blood loss,and lower plasma Ca^(2+).

关键词： Risk factors Pancreaticoduodenectomy Perioperative period Intraoperative persistent hypotension Retrospective cohort study

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Study on the Biological Characteristics,Pathogenicity Differentiation and Genetic Diversity of Sclerotinia minor Isolated from Different Hosts

Study on the Biological Characteristics,Pathogenicity Differ...

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中国植物病理学会2024年学术年会

作者： HAO Baizhen ZHANG Jian zhao Jun College of Horticulture and Plant Protection Inner Mongolia Agricultural University

Sclerotinia is a fungal disease caused by pathogenic fungi of the genus *** this study,we took Sclerotinia minor strains isolated from both sunflower and potato in different regions of Inner Mongolia as the objects of research and studied their biological characteristics,pathogenicity differentiation,and genetic ***,we isolated and purified 12 and 28 strains of *** separately from both potato and sunflower diseased plants,collected from Chahar Right-Wing Qian Banner of Ulaanchab *** isolates were confirmed to be *** by Koch's ***,the biological characteristics and pathogenicity of the above samples were *** results suggested that the growth rate of the mycelium of *** from potatoes was faster than that of *** from sunflower,but mycelium of *** from potatoes grew rather sparse on the PDA plate than that of isolates from *** was no significant difference on oxalic acid(OA) secretion and PG enzyme activity among all tested *** results of cross-infection suggested that *** from potato had a higher pathogenicity on its isolated host potato than that of the *** from sunflower;but there is no difference on the pathogenicity of all tested isolates on ***,Mycelium compatibility group(MCG) of tested isolates of *** from sunflower showed that the 120 isolates were divided into 21 MCG groups,and the isolates collected from the same sunflower field were distributed within different MCG *** isolates from potatoes were also classified into four different MCG *** results of mating types identification suggested that Inv-was the dominant type among all tested *** analysis results indicated that 26 strains of *** from sunflower and 10 strains of *** from potato s were interspersed in different genetic clusters,indicating the dramatic genetic difference of *** isolated from both sunflower and *** summary,this is

关键词： Sclerotinia minor Biological characteristics Genetic diversity Pathogenicity differentiation Genetic transformation

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