检索结果-南通市图书馆

Resolution Enhancement of SOHO/MDI Magnetograms

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第6期24卷 358-367页

作者： Ying Qin Kai-Fan Ji Hui Liu Xiao-guang yu yunnan Observatories Chinese Academy of SciencesKunming 650011China University of Chinese Academy of Sciences Beijing 100049China yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

Research on the solar magnetic field and its effects on solar dynamo mechanisms and space weather events has benefited from the continual improvements in instrument resolution and measurement *** augmentation and assimilation of historical observational data timelines also play a significant role in understanding the patterns of solar magnetic field *** the realm of astronomical data processing,super-resolution(SR)reconstruction refers to the process of using a substantial corpus of training data to learn the nonlinear mapping between low-resolution(LR)and high-resolution(HR)images,thereby achieving higherresolution astronomical *** paper is an application study in high-dimensional nonlinear *** learning models were employed to perform SR modeling on SOHO/MDI magnetograms and SDO/HMI magnetograms,thus reliably achieving resolution enhancement of full-disk SOHO/MDI magnetograms and enhancing the image resolution to obtain more detailed *** this study,a data set comprising 9717pairs of data from 2010 April to 2011 February was used as the training set,1332 pairs from 2011 March were used as the validation set and 1034 pairs from 2011 April were used as the test *** data preprocessing,we randomly cropped 128×128 sub-images as the LR cases from the full-disk MDI magnetograms,and the corresponding 512×512 sub-images as HR ones from the HMI full-disk magnetograms for model *** tests conducted have shown that the study successfully produced reliable 4×SR reconstruction of full-disk MDI *** MESR model's results(0.911)were highly correlated with the target HMI magnetographs as indicated by the correlation coefficient ***,the method achieved the best PSNR,SSIM,MAE and RMSE values,indicating that the MESR model can effectively reconstruct magnetograms.

关键词： magnetic fields techniques:image processing virtual observatory tools Sun:magnetic fields

Research on shell-side heat and mass transfer with multi-component in LNG spiral-wound heat exchanger under sloshing conditions

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1333-1345页

作者： Xue-Ping Du guang-Lei yu Ya-Cheng Xu Zhi-Jie Chen Nai-Liang Li Huan-guang Wang School of Low-carbon Energy and Power Engineering China University of Mining and TechnologyXuzhou221116JiangsuChina Key Laboratory of Thermo-Fluid Science and Engineering MOEXi'an Jiaotong UniversityXi'an710049ShaanxiChina Xi'an Aerospace Propulsion Test Technology Institute Xi'an710100ShaanxiChina

The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper studied the shell-side heat and mass transfer characteristics of vapor-liquid two-phase mixed refrigerants in an SWHE by combining a multi-component model in FLUENT software with a customized multicomponent mass transfer model. Besides, the mathematical model under the sloshing condition was obtained through mathematical derivation, and the corresponding UDF code was loaded into FLUENT as the momentum source term. The results under the sloshing conditions were compared with the relevant parameters under the steady-state condition. The shell-side heat and mass transfer characteristics of the SWHE were investigated by adjusting the component ratio and other working conditions. It was found that the sloshing conditions enhance the heat transfer performance and sometimes have insignificant effects. The sloshing condition is beneficial to reduce the flow resistance. The comprehensive performance of multi-component refrigerants has been improved and the improvement is more significant under sloshing conditions, considering both the heat transfer and pressure *** results will provide theoretical support for the research and design of multi-component heat and mass transfer enhancement of LNG SWHE under ocean sloshing conditions.

关键词： Spiral-wound heat exchanger Sloshing conditions Two-phase flow Multi-component Heat and mass transfer

Study on tungsten sintering temperature field based on electromagnetic simulation and computational fluid dynamics

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第2期6卷 355-366页

作者： Lu-Yan Wang yue-guang yu Jian-Xin Dong Kai-Ping Du Shan-yu Liu Cao-Bing Li University of Science and Technology Beijing Beijing 100083China BGRIMM Technology Group Beijing 100160China China Iron&Steel Research Institute Group Beijing 100081China

In order to study the influence of various sintering variables more intuitively and clearly,electromagnetic field analysis and computational fl uid dynamics are used to analyze the infl uence of gas flow,heating power and other process parameters on the temperature range of medium-frequency sintering in this *** results indicate that the uniformity of temperature fi eld is determined by the gas flow rate and heating *** the heating power is 50 kW,the stable temperature drops about 10 K for every 1 m^(3)·h^(−1)increase of hydrogen *** peak value of the maximum temperature diff erence on the tungsten rods gradually increases with the increase of the hydrogen flow rate,and it appears slightly *** temperature distribution of tungsten rods in furnace is similar with diff erent hydrogen flow *** the same time,the closer to the furnace wall,the higher the temperature of the tungsten *** temperature diff erence between tungsten rods mainly occurred within 1 h after the beginning of *** the heating power can improve the stable temperature,but has little eff ect on the heating *** heating power can increase the peak value of the maximum temperature diff erence on the tungsten rods,but has little eff ect on the occurrence time of the peak value of the maximum temperature diff erence on the tungsten *** the heating power will increase the temperature diff erence of a single tungsten rod,but the temperature diff erence of a single tungsten rod never exceeds 65 *** study can be used to guide the process optimization *** with numerical simulation calculation,the sintering parameters with low energy consumption and high temperature uniformity can be quickly and eff ectively found,thus improving the microstructure and properties of sintered tungsten products.

关键词： Tungsten products Sintering Hydrogen flow rate Heating power

Impact of COVID-19-related lifestyle changes on diabetic macular edema

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第1期17卷 97-106页

作者： Bryce P.Johnson yu-guang He Zachary M.Robertson Angeline Wang Rafael L.Ufret-Vincenty Department of Ophthalmology UT Southwestern Medical CenterDallasTexas 75390-9057USA

AIM:To assess diabetic macular edema(DME)progression during the early phases of the COVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions,particularly those requiring frequent office ***:This is a multicenter retrospective chart review of 370 patients(724 eyes)with an established diagnosis of DME seen on 3 separate visits between January 2019 and July *** 1 was January 2019 to February 2020(considered pre-COVID-19),period 2 was March 2020 to December 2020(considered the height of the pandemic;highest level of pandemic-related clinical and societal regulations)and period 3 was January 2021 to July 2021(re-adjustment to the new“pandemic norms”).Main outcome measures included visual acuity,body mass index(BMI),blood pressure(BP),hemoglobin A1c(HbA1c),macular thickness,patient adherence to scheduled ophthalmology visits,and DME treatment(s)received at each *** facilitate measurement of macular thickness,each macula was divided into 9 Early Treatment Diabetic Retinopathy Study(ETDRS)-defined macular sectors as measured by OCT ***:There was no change of BMI,systolic BP,and diastolic BP between any of the time ***1c showed a very small increase from period 1(7.6%)to period 2(7.8%,P=0.015)and decreased back to 7.6%at period 3(P=0.12).Macular thickness decreased for 100%of macular *** central macular thickness decreased across all 3 periods from 329.5 to 316.6μm(P=0.0045).After analysis of multiple variables including HbA1c,BMI,adherence to scheduled appointments,different clinic centers,and treatment interventions,there was no easily identifiable subgroup of patients that experienced the increase in ***:DME doesn’t worsen during the COVID-19 pandemic,instead sustaining a very small but statistically significant *** identifying a mechanism behind our findings is beyond the scope of this study,potential explanat

关键词： COVID-19 diabetic macular edema diabetic retinopathy optical coherence tomography

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

磷系阻燃环氧电子封装材料研究进展

高分子通报 2024年第5期37卷 630-639页

作者：于光深圳职业技术大学传播工程学院深圳518055

磷系阻燃环氧树脂具有阻燃效率高、制备成本低、环境危害小等显著优点,成为5G通讯、智能电子和半导体等领域的重要封装材料。基于高效磷系阻燃环氧封装材料的性能要求,介绍了磷系阻燃环氧树脂的种类和阻燃机理,总结了当前磷系阻燃环氧... 详细信息

磷系阻燃环氧树脂具有阻燃效率高、制备成本低、环境危害小等显著优点,成为5G通讯、智能电子和半导体等领域的重要封装材料。基于高效磷系阻燃环氧封装材料的性能要求,介绍了磷系阻燃环氧树脂的种类和阻燃机理,总结了当前磷系阻燃环氧树脂在电子封装领域的应用研究进展并对其未来发展趋势进行了展望,指出本征型(反应型)磷系阻燃环氧树脂存在制备困难、有效磷含量低等问题,需要进一步优化工艺并提升封装体系中的磷含量。相比之下,填充型磷系阻燃环氧树脂的制备工艺简单、阻燃剂种类多、磷含量较高,在电子封装领域应用最为广泛。

关键词：磷系阻燃阻燃效率环氧树脂电子封装阻燃机理

同方期刊数据库

论国民政府财政的不经济增长:以卷烟业中的税和债为线索

在线全文

学校读者我要写书评

暂无评论

社会科学 2024年第6期 69-84页

作者：于广上海社会科学院历史研究所

增加税收与发行债券,是国民政府解决财政危机的重要办法。在国民政府的统税收入中,有接近八成来自卷烟,以卷烟统税为担保品的卷烟国库券亦是国民政府最早发行的债券之一。国民政府初期有意恢复政府债信,每笔卷烟国库券都有税收的具实担... 详细信息

增加税收与发行债券,是国民政府解决财政危机的重要办法。在国民政府的统税收入中,有接近八成来自卷烟,以卷烟统税为担保品的卷烟国库券亦是国民政府最早发行的债券之一。国民政府初期有意恢复政府债信,每笔卷烟国库券都有税收的具实担保,但国库券的市场价格却持续走低,与税收增长形成背离。受“大萧条”等一系列经济和政治的不利因素影响,1932年国民政府取消了债券的具实担保,鼓励金融界向公债市场投资,公债价格反而出现与税收齐升的局面。然而,由此带来的财政增长是一种不经济增长,一定程度上阻碍着实业经济的良性发展,为日后国民政府的财政崩溃埋下伏笔。

关键词：财政税收债券卷烟不经济增长

基于强化学习的遗传算法求解一种新的钻削路径优化问题

在线全文

学校读者我要写书评

暂无评论

控制与决策 2024年第2期39卷 697-704页

作者：朱光宇张德颂福州大学机械工程及自动化学院福州350108

孔加工是机械制造的基本工序之一.针对数控机床的刀具路径优化问题,提出一种新颖的孔加工刀具路径优化模型—–带可决策孔的孔加工多刀具路径优化问题(MTdDPO).在该模型中,工件上的孔分为两类:固定孔和可决策孔. MTdDPO的目标是通过判... 详细信息

孔加工是机械制造的基本工序之一.针对数控机床的刀具路径优化问题,提出一种新颖的孔加工刀具路径优化模型—–带可决策孔的孔加工多刀具路径优化问题(MTdDPO).在该模型中,工件上的孔分为两类:固定孔和可决策孔. MTdDPO的目标是通过判断可决策孔的路径归属和路径内各孔的加工顺序来实现加工路径长度的最小化.为实现MTdDPO的优化,提出基于强化学习的分段遗传算法(RLSGA).在RLSGA中,种群被视为智能体,智能体的状态是种群的多样性系数, 3种不同的分段交叉算子是智能体的动作,智能体的奖励与种群的适应度值和多样性系数的变化有关.针对MTdDPO,新建5个基准测试问题,并在测试问题上将RLSGA与其他4个算法进行对比.结果表明, RLSGA的表现明显优于其他算法, RLSGA能够有效地解决MTdDPO问题.

关键词：孔加工路径优化遗传算法强化学习组合优化

Mental health and insomnia problems in healthcare workers after the COVID-19 pandemic:A multicenter cross-sectional study

在线全文

学校读者我要写书评

暂无评论

World Journal of Psychiatry 2024年第5期14卷 704-714页

作者： Wei Ding Min-Zhong Wang Xian-Wei Zeng Zhen-Hua Liu Yao Meng Hui-Ting Hu yuan Zhang yu-guang Guan Fan-Gang Meng Jian-Guo Zhang Shu Wang Department of Public Health Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina Department of Neurology Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina Department of Neurosurgery Qilu Hospital of Shandong UniversityJinan 250012Shandong ProvinceChina Sleep Medicine Center Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina Department of Neurology The First Affiliated Hospital of Shandong First Medical UniversityJinan 250014Shandong ProvinceChina Department of Neurology Heze Mudan People’s HospitalHeze 274000Shandong ProvinceChina Neonatal Center Beijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthBeijing 100045China Department of Neurosurgery SanBo Brain HospitalCapital Medical UniversityBeijing 100093China Department of Neurosurgery Beijing Tiantan HospitalCapital Medical UniversityBeijing 100070China

BACKGROUND Healthcare workers(HCWs)are at increased risk of contracting coronavirus disease 2019(COVID-19)as well as worsening mental health problems and *** problems can persist for a long period,even after the ***,less is known about this *** To analyze mental health,insomnia problems,and their influencing factors in HCWs after the COVID-19 *** This multicenter cross-sectional,hospital-based study was conducted from June 1,2023 to June 30,2023,which was a half-year after the end of the COVID-19 ***-stratified population-based cluster sampling was applied at the provincial level for Chinese *** such as anxiety,depression,and insomnia were evaluated by the Generalized Anxiety Disorder-7,Patient Health Questionnaire-9,and Insomnia Severity *** influencing the symptoms were identified by multivariable logistic *** A total of 2000 participants were invited,for a response rate of 70.6%.A total of 1412 HCWs[618(43.8%)doctors,583(41.3%)nurses and 211(14.9%)nonfrontline],254(18.0%),231(16.4%),and 289(20.5%)had symptoms of anxiety,depression,and insomnia,respectively;severe symptoms were found in 58(4.1%),49(3.5%),and 111(7.9%)of the ***,female sex,and hospitalization for COVID-19 were risk factors for anxiety,depression,and insomnia symptoms;moreover,death from family or friends was a risk factor for insomnia *** the COVID-19 outbreak,most[1086(76.9%)]of the participating HCWs received psychological interventions,while nearly all[994(70.4%)]of them had received public psychological *** 102(7.2%)of the HCWs received individual counseling from *** Although the mental health and sleep problems of HCWs were relieved after the COVID-19 pandemic,they still faced challenges and greater risks than did the general *** risk factors would help in providing targeted *** addition,although a major proportion of

关键词： COVID-19 Mental health Psychological symptoms Insomnia Sleep disorders Cross-sectional study Epidemiological study

基于环状构象两性离子聚合物的抗粘附/光热杀菌表面性能分析

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

分析化学 2024年第5期52卷 717-724页

作者：夏效禹张光宇苏朝晖中国科学院长春应用化学研究所高分子物理与化学国家重点实验室中国科学技术大学应用化学与工程学院

耐药细菌附着在医疗器械表面易引起感染，对公众健康造成严重威胁，因此，研发长效抗粘附与杀菌表面具有重要的意义。本研究在玻璃基底表面顺序沉积聚多巴胺(PDA)、银纳米粒子(AgNPs)和PDA，然后在PDA表面接枝环状构象的聚磺酸甜菜碱(PS... 详细信息

耐药细菌附着在医疗器械表面易引起感染，对公众健康造成严重威胁，因此，研发长效抗粘附与杀菌表面具有重要的意义。本研究在玻璃基底表面顺序沉积聚多巴胺(PDA)、银纳米粒子(AgNPs)和PDA，然后在PDA表面接枝环状构象的聚磺酸甜菜碱(PSBMA)，构建了具有抗粘附与光热杀菌作用的双重抗菌涂层PAP-PSBMA-loop。该涂层具有两性离子聚合物表面优良的抗污能力和PDA与AgNPs良好的光热转化能力，在近红外光辐照下显示出优异的抗细菌粘附与杀菌性能，与细菌共孵育7 d后，表面的细菌覆盖率仅为1.7%，有效地阻止了生物被膜的形成，在光照下可杀灭99%以上的表面细菌。

关键词：光热杀菌抗菌表面环状构象抗污涂层银纳米粒子