检索结果-南通市图书馆

Molecular composition of low-temperature oxidation products of the heavy oil

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2023年第5期20卷 3264-3271页

作者： Shuai Ma yun-yun li Ri-Gu Su Xu-Sheng Wang Jing-Jun Pan Quan Shi Guang-Zhi liao Chun-Ming Xu State Key Laboratory of Heavy Oil Processing Petroleum Molecular Engineering Center(PMEC)China University of PetroleumBeijing102249China Engineering Technology Research Institute of PetroChina Xinjiang Oilfield Company Karamay834000XinjiangChina CAS Lanzhou Institute of Chemical Physics Lanzhou730000GansuChina PetroChina Exploration&Production Company Beijing100007China

Low-temperature oxidation(LTO)is the main reaction that affects fuel formation in the in-situ combustion process,which has important significance for the subsequent combustion propulsion and the successful extraction of crude *** this study,heavy oil was subjected to LTO reactions at different *** types of reaction products with varying oxidation depths were characterized in terms of the number of oxygen atoms and the polarity of the molecule to reveal the low-temperature oxidation process of the heavy *** compounds and acid polyoxides in the oil phase and deep oxidation products with a higher number of oxygen atoms in the coke were identified with increasing oxidation *** experimental results showed that the oxidation reaction of the heavy oil changed from kinetic-controlled to diffusion-controlled in the open oxidation system of the heavy oil as the oxidation depth *** oxidation reaction of the oil phase reached a maximum and stable value in oxygen *** molecular compositions of the ketone compound and acid polyoxide did not change significantly with further increase in reaction *** molecular compositions of the deep oxidation products with a higher number of oxygen atoms in the coke phase changed *** coke precursor molecules with a lower oxygen content and condensation degree participated in the coke formation,and the oxidation reaction pathway and the complexity of the oxidation product component also increased.

关键词： Low-temperature oxidation In-situ combustion Heavy oil Coke precursor Molecular composition

The Beijing Desheng Diabetic Eye Study:rationale,design,methodology and baseline data

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2018年第1期11卷 108-116页

作者： yun-yun li Xiu-Fen Yang Hong Gu Xi-Pu liu Torkel Snellingen Ning-Pu liu Beijing Tongren Eye Center Beijing Tongren HospitalCapital Medical UniversityBeijing Ophthalmology and VisualSciences Key LaboratoryBeijing 100730China Department of Ophthalmology Friendship HospitalCapitalMedical UniversityBeijing 100050China Department of Ophthalmology Ningbo Medical TreatmentCenter Lihuili HospitalNingbo 315040Zhejiang ProvinceChina Sekwa Institute of Medicine Beijing 100035China

AIM： To present the rationale, design, methodology, and the baseline data of the Beijing Desheng Diabetic Eye Study（BDDES）, and to determine the prevalence of diabetic retinopathy（DR） and possible risk factors in patients with type 2 diabetes mellitus（T2DM） in an urban community of Beijing, ***： Community-based prospective cohort study of persons diagnosed with T2DM aged 30 y or older. The main variables of interest are the presence and progression of DR as determined by the standardized ETDRS grading of seven fields fundus photographs. The presence and severity of DR were analyzed for possible correlations to non-genetic and genetic ***： A total of 1438 participants with data available for analysis, the prevalence of any DR was 35.4%. The prevalence of mild non-proliferative diabetic retinopathy（NPDR）, moderate NPDR, severe NPDR, and proliferative diabetic retinopathy was 27.7%, 2.6%, 0.5% and 4.5%, respectively. By multiple logistic regression analysis, risk factors for the presence of any DR included male（P=0.031）, lower income level（P=0.011）, lower education background（P=0.022）, longer duration of diabetes（P=0.001）, younger age at diabetic onset（P=0.001）, higher systolic blood pressure（P=0.007）, higher glycosylated hemoglobin A1 c levels（P=0.001）, high albuminuria（P=0.03）, and use of insulin（P〈0.001）. For vision-threatening DR, four factors were significant： younger age at diabetic onset（P〈0.001）,higher systolic blood pressure（P=0.042）, high albuminuria（P〈0.001）, and use of insulin（P〈0.001）. CONCLUSION： The BDDES is the first large-scale ongoing cohort study of a Chinese urban population of persons with type 2 diabetes. Using standardized grading system comparable to large cohort studies from western populations, our baseline data shows that the prevalence of DR and major risk factors in this Chinese ethnic population are comparable to that found in the western population studies.

关键词： type 2 diabetes mellitus diabetic retinopathy risk factors cohort study

The relationship between insulin resistance/β-cell dysfunction and diabetic retinopathy in Chinese patients with type 2 diabetes mellitus： the Desheng Diabetic Eye Study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2018年第3期11卷 493-500页

作者： yun-yun li Xiu-Fen Yang Hong Gu Torkel Snellingen Xi-Pu liu Ning-Pu liu Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology and Visual Sciences Key Laboratory Beijing 100730 China Department of Ophthalmology Friendship Hospital Capital Medical University Beijing 100050 China Department of Ophthalmology Lihuili Hospital Ningbo 315040 Zhejiang Province China Sekwa Institute of Medicine Beijing 100035 China

AIM： To investigate the relationship between insulin resistance （IR）/β-cell dysfunction and diabetic retinopathy （DR） in Chinese patients with type 2 diabetes mellitus （T2DM）, and to explore further whether there were differences in the relationship among diabetic patients with higher and lower body mass index （BMI）. METHODS： Cross-sectional study. A total of 1466 subjects with T2DM were recruited in a local Desheng Community of urban Beijing from November 2009 to June 2012 for the cohort of Beijing Desheng Diabetic Eye Study. Standardized evaluation was carried out for each participant, including questionnaire, ocular and anthropometric examinations, and laboratory tests. Seven fields 30° color fundus photographs were used for DR grading according to the Early Treatment Diabetic Retinopathy Study protocols. Homeostatis Model Assessment （HOMA） method was employed for IR and β-cell function assessment. RESULTS： After excluding those participants who were treated with insulin （n=352） or had missing data of fasting insulin （n=96）, and further excluding those with poor quality of retinal photographs （n=10）, a total of 1008 subjects were included for the final analysis, 406 （40.3%） were men and 602 （59.7%） were women, age ranging fiom 34 to 86 （64.87±8.28）y. Any DR （levels 14 and above） was present in 278 （27.6%） subjects. After adjusting for possible covariates, the presence of any DR did not correlate with HOMA IR [odds ratio （OR） 1.51, 95% confidence interval （Cl） 0.87-2.61, P=0.14] or HOMA β-cell （OR 0.71, 95%CI 0.40-1.26, P=0.25）. After stratification by BMI, the presence of any DR was associated positively with HOMA IR （OR 2.46, 95%CI： 1.18-5.12, P=0.016）, and negatively with HOMA β-cell （OR 0.40, 95%CI： 0.19-0.87, P=0.021） in the group of patients with higher BMI （225 kg/m2）. In the group of patients with lower BMI （〈25 kg/m2）, the presence of any DR was not associated with HOMA IR （OR 1.00, 95%C1： 0.43-2.33, P=I.00） or HOMA β-cell （OR 1.41, 95%CI： 0.60-3.32, P=

关键词： type 2 diabetes mellitus diabetic retinopathy insulin resistance β-cell function body mass index

Visual impairment with possible macular changes after a high dose of sildenafil in a healthy young woman

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2018年第2期11卷 340-342页

作者： yun-yun li Ya-Jie Yu Xi-Pu liu Ning-Pu liu Beijing Tongren Eye Center Beijing Tongren HospitalCapital Medical UniversityBeijing 100730China Sekwa Institute of Medicine Beijing 100035China

Dear Editor,Sildenafil citrate（Viagra;Pfizer Pharmaceuticals,New York,NY,USA）,a selective inhibitor of phosphodiesterase type 5（PDE-5）,is widely used for erectile *** clinical recommended dosage is 25 to 100 mg pe... 详细信息

关键词： Visual impairment with possible macular changes after a high dose of sildenafil in a healthy young woman PDE Figure

Observer-based Output-feedback Stabilization Control Design for a Class of Nonlinear Uncertain Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

自动化学报 2006年第1期32卷 101-106页

作者： ZHANG yun liU yun-Gang li Yan-Fang School of Control Science and Engineering Shandong University Jinan 250061

The output-feedback stabilization control problem is investigated for a class of nonlinear uncertain systems. Based on the multivariable analog of circle criterion, an observer is designed to estimate the system states and hence the dynamical equations that the estimation error satisfies are derived first. Then, by using integral backstepping approach together with completing square technique, the output-feedback stabilization control is constructively designed such that the closed-loop system is asymptotically stable. Finally, an example is given to illustrate the main results of this paper.

关键词：非线性系统不确定性输出反馈稳定性误差估计

Sex-dependent alterations in extracellular vesicles linking chronic spinal cord injury to brain neuroinflammation and neurodegeneration

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 483-484页

作者： yun li Junfang Wu Department of Anesthesiology&Shock Trauma and Anesthesiology Research(STAR)CenterUniversity of Maryland School of MedicineBaltimoreMDUSA

Traumatic spinal cord injury(SCI)is a devastating exogenous injury with long-lasting consequences and a leading cause of death and disability *** in assistive technology,rehabilitative interventions,and the ability to identify and intervene in secondary conditions have significantly increased the long-term survival rate of SCI patients,with some people even living well into their seventh or eighth *** survival changes have led neurotrauma researchers to examine how SCI interacts with brain *** health and epidemiological data showed that patients with long-term SCI can have a lower life expectancy and quality of life,along with a higher risk of comorbidities and complications.

关键词： alterations inflammation injury

Altered Retinal Dopamine Levels in a Melatonin-proficient Mouse Model of Form-deprivation Myopia

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2022年第9期38卷 992-1006页

作者： Kang-Wei Qian yun-yun li Xiao-Hua Wu Xue Gong Ai-lin liu Wen-Hao Chen Zhe Yang ling-Jie Cui yun-Feng liu Yuan-Yuan Ma Chen-Xi Yu Furong Huang Qiongsi Wang Xiangtian Zhou Jia Qu Yong-Mei Zhong Xiong-li Yang Shi-Jun Weng State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institutes of Brain ScienceFudan UniversityShanghai200032China Discipline of Neuroscience and Department of Anatomy and Physiology College of Basic Medical SciencesShanghai Jiao Tong University School of MedicineShanghai200025China School of Ophthalmology and Optometry and Eye Hospital Wenzhou Medical UniversityWenzhou325027China Department of Immunology School of Basic Medical SciencesAnhui Medical UniversityHefei230032China

Reduced levels of retinal dopamine,a key regulator of eye development,are associated with experimental myopia in various species,but are not seen in the myopic eyes of C57BL/6 mice,which are deficient in melatonin,a neurohormone having extensive interactions with ***,we examined the relationship between form-deprivation myopia(FDM)and retinal dopamine levels in melatonin-proficient CBA/CaJ *** found that these mice exhibited a myopic refractive shift in form-deprived eyes,which was accompanied by altered retinal dopamine *** melatonin receptors were pharmacologically blocked,FDM could still be induced,but its magnitude was reduced,and retinal dopamine levels were no longer altered in FDM animals,indicating that melatonin-related changes in retinal dopamine levels contribute to ***,FDM is mediated by both dopamine level-independent and melatonin-related dopamine level-dependent mechanisms in CBA/CaJ *** previously reported unaltered retinal dopamine levels in myopic C57BL/6 mice may be attributed to melatonin deficiency.

关键词： Myopia Refractive development Dopamine Melatonin Mouse Retina

IoT Empowered Early Warning of Transmission line Galloping Based on Integrated Optical Fiber Sensing and Weather Forecast Time Series Data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 1171-1192页

作者： Zhe li yun liang Jinyu Wang Yang Gao State Grid Henan Electric Power Company Electric Power Scientific Research Institute State Grid Henan Electric Power CompanyZhengzhou450052China

Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power *** early warning methods of iced transmission line galloping suffer from issues such as reliance on a single data source,neglect of irregular time series,and lack of attention-based closed-loop feedback,resulting in high rates of missed and false *** address these challenges,we propose an Internet of Things(IoT)empowered early warning method of transmission line galloping that integrates time series data from optical fiber sensing and weather ***,the method applies a primary adaptive weighted fusion to the IoT empowered optical fiber real-time sensing data and weather forecast data,followed by a secondary fusion based on a Back Propagation(BP)neural network,and uses the K-medoids algorithm for clustering the fused ***,an adaptive irregular time series perception adjustment module is introduced into the traditional Gated Recurrent Unit(GRU)network,and closed-loop feedback based on attentionmechanism is employed to update network parameters through gradient feedback of the loss function,enabling closed-loop training and time series data prediction of the GRU network ***,considering various types of prediction data and the duration of icing,an iced transmission line galloping risk coefficient is established,and warnings are categorized based on this ***,using an IoT-driven realistic dataset of iced transmission line galloping,the effectiveness of the proposed method is validated through multi-dimensional simulation scenarios.

关键词： Optical fiber sensing multi-source data fusion early warning of galloping time series data IoT adaptive weighted learning irregular time series perception closed-loop attention mechanism

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

关于训练理论研究中若干方法论问题的思考

北京体育大学学报 2017年第5期40卷 94-99页

作者：苏芸澐李少丹北京体育大学北京100084

我国训练理论研究水平仍处在经验阶段,训练理论的治理迫在眉睫。运用文献资料法、时序法等研究方法,以科学技术哲学与复杂性科学为研究视角,从方法论层面试厘清训练理论研究中所出现的问题,以及未来研究趋向等问题。研究认为复杂性是认... 详细信息

我国训练理论研究水平仍处在经验阶段,训练理论的治理迫在眉睫。运用文献资料法、时序法等研究方法,以科学技术哲学与复杂性科学为研究视角,从方法论层面试厘清训练理论研究中所出现的问题,以及未来研究趋向等问题。研究认为复杂性是认识训练规律的路径、科学理性是提升训练理论着眼点、学科交叉性是促进训练理论增长点、非线性是促使训练理论研究转型、整体性是表达训练理论的要义。通过提出超越传统意义上的方法论纲领,以期加快竞技体育治理体系和治理能力的现代化,适应国家竞技体育发展战略的需求;希冀训练理论对现代训练实践的要求做出科学地解释与说明,实现训练理论在实践中的应用性和操作性。

关键词：训练理论方法理论复杂性科学研究趋向战略需求