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Nano Research 2024年第1期17卷 407-415页

作者： yumei ma Lijie Zhang Kang Zhu Binze Zhang Ranran Peng Changrong Xia Ling Huang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China Department of materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Promoting the oxygen reduction reaction(ORR)is critical for commercialization of intermediate-temperature solid oxide fuel cells(IT-SOFCs),where Sr_(2)Fe_(1.5)Mo_(0.5)O_(6)−δ(SFM)is a promising cathode by working as a mixed ionic and electronic conductor.In this work,doping of In^(3+)greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in Sr_(2)Fe_(1.5)Mo_(0.5−x)InxO_(6−δ)(SFMInx),and thus effectively promotes the ORR performance.As a typical example,SFMIn_(0.1)reduces the polarization resistance(R_(p))from 0.089 to 0.046Ω∙cm^(2)at 800°C,which is superior to those doped with other metal elements.In addition,SFMIn0.1 increases the peak power density from 0.92 to 1.47 W∙cm^(−2)at 800°C with humidified H_(2)as the fuel,indicating that In3+doping at the Mo site can effectively improve the performance of SOFC cathode material.

关键词： solid oxide fuel cell cathode In3+doping oxygen reduction reaction(ORR) Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)

Research on Image Signal Identification Based on Adaptive Array Stochastic Resonance

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Journal of Systems Science & Complexity 2022年第1期35卷 179-193页

作者： ZHAO Jingjing ma yumei PAN Zhenkuan ZHANG Huage College of Computer Science&Technology Qingdao UniversityQingdao 266071China.

Aiming at the problems of low accuracy of image signal identification and poor anti-noise signal interference ability under strong noise environment,a signal identification method of correlated noisy image based on adaptive array stochastic resonance(SR)is proposed in this paper.Firstly,the two-dimensional grayscale image is transformed to a one-dimensional binary pulse amplitude modulation(BPAM)signal with periodicity by the row or column scanning method,encoding and modulation.Then,the one-dimensional low signal-to-noise ratio BPAM signal can be applied to the saturating nonlinearity array SR module for image signal identification processing and part of the noise energy is converted into signal energy.Finally,the one-dimensional image signal processed by the nonlinearities is demodulated,decoded and reverse scanned to get the restored grayscale image.The simulation results show that the image signal identification method proposed in this paper is highly efficient and accurate for the identification of noisy image signals of different sizes,and the bit error rate(BER)is also significantly reduced.

关键词： Array stochastic resonance bit error rate image restoration saturating nonlinearity signal identification

Barrier Lyapunov Function-Based Finite-Time Dynamic Surface Control for Output-Constrained Nonstrict-Feedback Systems

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Journal of Systems Science & Complexity 2023年第2期36卷 524-539页

作者： YU Jinpeng FU Cheng LIU Jiapeng ma yumei The College of Automation Qingdao UniversityQingdao 266003China Shandong Key Laboratory of Industrial Control Technology Qingdao UniversityQingdao 266003China The School of Control Science and Engineering Shandong UniversityJinan 250100China

This paper investigates a finite-time tracking problem for the uncertainty nonlinear systems in nonstrict-feedback form,in which the output signal is restricted in a region.Based on the barrier Lyapunov function and dynamic surface control scheme,a novel adaptive neural controller is proposed by using the finite-time Lyapunov technology.Unlike the aforementioned literature on finite time tracking control,the violation of system output constraint is avoided by combining the barrier Lyapunov function method with finite-time theory.The structural characteristics of neural network is introduced to expand the adaptive neural finite-time backstepping method to the uncertainty nonlinear systems in the non-strict form.Correspondingly,the dynamic surface control is introduced to cope with the problem of“explosion of complexity”inherent in conventional backstepping scheme.It is shown that the designed controller can achieve finite-time tracking control and all the variables in the closed-loop system are bounded with output constraint guaranteed form stability analysis and simulation results.

关键词： Adaptive neural network control explosion of complexity finite-time tracking nonstrictfeedback form

Identification for the Low-Contrast Image Signal with Regularized Variational Term and Dynamical Saturating Nonlinearity

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Journal of Systems Science & Complexity 2023年第3期36卷 1089-1102页

作者： ZHANG Ning ma yumei PAN Zhenkuan HUANG Baoxiang WANG Dongcheng College of Computer Science&Technology Qingdao UniversityQingdao 266071China

In recent years,image processing based on stochastic resonance(SR)has received more and more attention.In this paper,a new model combining dynamical saturating nonlinearity with regularized variational term for enhancement of low contrast image is proposed.The regularized variational term can be setting to total variation(TV),second order total generalized variation(TGV)and non-local means(NLM)in order to gradually suppress noise in the process of solving the model.In addition,the new model is tested on a mass of gray-scale images from standard test image and low contrast indoor color images from Low-Light dataset(LOL).By comparing the new model and other traditional image enhancement models,the results demonstrate the enhanced image not only obtain good perceptual quality but also get more excellent value of evaluation index compared with some previous methods.

关键词： Dynamical saturating nonlinearity image enhancement low contrast regularized variational term stochastic resonance(SR)

“双碳目标”下中国乳业财务绩效评价研究——以伊利集团为例

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中国乳业 2024年第1期 22-27页

作者：马玉梅兰州财经大学甘肃兰州730030

“双碳目标”的提出使各大行业纷纷步入转型浪潮,于是低碳环保、节能减排措施后形成的财务绩效水平成为企业较关注的问题。本文以中国乳业中具有代表性的伊利集团为研究对象,对其财务指标按照熵权法确定权重后再分析和ESG评价体系法进... 详细信息

“双碳目标”的提出使各大行业纷纷步入转型浪潮,于是低碳环保、节能减排措施后形成的财务绩效水平成为企业较关注的问题。本文以中国乳业中具有代表性的伊利集团为研究对象,对其财务指标按照熵权法确定权重后再分析和ESG评价体系法进行双重分析,最终总结了该企业提升绩效水平的措施,给中国乳业以启示。

关键词：双碳目标熵权法财务绩效

Hydrobios and Control of Eutrophication in Dongping Lake,Shandong Province

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Acta Geologica Sinica(English Edition) 2000年第2期74卷 329-333页

作者： DOU Suzhen SUN Zhaocai CAO Ying ma yumei ZHANG Jingfu LIU Guicheng KOU Xiaoyan Environmental Protection and Monitoring Station of Taian City Tai’an 271000 Shandong Environmental Protection Bureau of Dongping County Dongping 271500 Shandong

The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growth and propagation of hydrophyta, therefore the key to the prevention and control of eutrophication in lakes lies in the control of the contents of the two elements in the water. Artificial fishing of algae can reduce the concentrations of trophic substances such as nitrogen and phosphorus in the water bodies, and biological measures may decrease the contents of these trophic substances in the bottom sediments and the water bodies, thereby playing an active role in modifying the eutrophication of the lake.

关键词： Dongping Lake hydrobios eutrophication biological evaluation prevention and control measures

Transient Characteristics and Quantitative Analysis of Electromotive Force for DFIG-based Wind Turbines during Grid Faults

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Chinese Journal of Electrical Engineering 2022年第2期8卷 3-12页

作者： yumei ma Donghai Zhu Xudong Zou Yong Kang Josep M.Guerrero Key Laboratory of Power Electronics and Energy management for Ministry of Education of China Huazhong University of Science and TechnologyWuhan 430074China Department of Energy Technology Aalborg UniversityAalborg 9220Denmark

For doubly-fed induction generator(DFIG)-based wind turbines(WTs),various advanced control schemes have been proposed to achieve the low voltage ride through(LVRT)capability,whose parameters design is significantly reliant on the rotor electromotive force(EMF)of DFIG-based WTs.However,the influence of the rotor current on EMF is usually ignored in existing studies,which cannot fully reflect the transient characteristics of EMF.To tackle with this issue,this study presents a comprehensive and quantitative analysis of EMF during grid faults considering various control modes.First,the DFIG model under grid faults is established.Subsequently,the transient characteristics of EMF are analyzed under different control modes(that is,rotor open-circuit and connected to converter).Furthermore,the EMF transient eigenvolumes(that is,accessorial resistance item,transient decay time constant,and frequency offset)are quantitatively analyzed with the typical parameters of MW-level DFIG-based WT.The analysis results contribute to the design of the LVRT control scheme.Finally,the analysis is validated by the hardware-in-the-loop experiments.

关键词： Doubly-fed induction generator(DFIG) electromotive force(EMF) quantitative analysis transient characteristics wind turbines(WTs) grid faults

Changes in early postoperative outcomes and complications observed in a single center during the 2022 COVID-19 pandemic wave in China:A single-center ambispective cohort study

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Chinese Medical Journal 2023年第14期136卷 1708-1718页

作者： Lini Wang Ziyu Zheng Shouqiang Zhu Gang Luo Baobao Gao yumei ma Shuai Xu Hailong Dong Chong Lei Department of Anesthesiology and Perioperative Medicine Xijing HospitalFourth Military Medical UniversityXi’anShaanxi 710032China Anesthesia Clinical Research Center Xijing HospitalFourth Military Medical UniversityXi’anShaanxi 710032China

Background:Currently,the effect of the 2022 nationwide coronavirus disease 2019(COVID-19)wave on the perioperative prognosis of surgical patients in China is unclear.Thus,we aimed to explore its influence on postoperative morbidity and mortality in surgical patients.Methods:An ambispective cohort study was conducted at Xijing Hospital,China.We collected 10-day time-series data from December 29 until January 7 for the 2018-2022 period.The primary outcome was major postoperative complications(Clavien-Dindo class III-V).The association between COVID-19 exposure and postoperative prognosis was explored by comparing consecutive 5-year data at the population level and by comparing patients with and without COVID-19 exposure at the patient level.Results:The entire cohort consisted of 3350 patients(age:48.5±19.2 years),including 1759 females(52.5%).Overall,961(28.7%)underwent emergency surgery,and 553(16.5%)had COVID-19 exposure(from the 2022 cohort).At the population level,major postoperative complications occurred in 5.9%(42/707),5.7%(53/935),5.1%(46/901),9.4%(11/117),and 22.0%(152/690)patients in the 2018-2022 cohorts,respectively.After adjusting for potential confounding factors,the 2022 cohort(80%patients with COVID-19 history)had a significantly higher postoperative major complication risk than did the 2018 cohort(adjusted risk difference[aRD],14.9%(95%confidence interval[CI],11.5-18.4%);adjusted odds ratio[aOR],8.19(95%CI,5.24-12.81)).At the patient level,the incidence of major postoperative complications was significantly greater in patients with(24.6%,136/553)than that in patients without COVID-19 history(6.0%[168/2797];aRD,17.8%[95%CI,13.6-22.1%];aOR,7.89[95%CI,5.76-10.83]).Secondary outcomes of postoperative pulmonary complications were consistent with primary findings.These findings were verified through sensitivity analyses using time-series data projections and propensity score matching.Conclusion:Based on a single-center observation,patients with recent COVID-19 exposure were likely to have a high incidenc

关键词： COVID-19 Decision-making Surgery Omicron Postoperative complications

富硒土地开发利用评价体系的建立及应用——以西安市临潼区为例

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中国地质 2024年第2期51卷 676-688页

作者：任蕊晁旭张立君支倩徐翠玲凌丹丹马宇梅陈继平乔新星杜少喜陕西省水工环地质调查中心陕西西安710068 陕西省地质调查规划研究中心(陕西省地质勘查基金中心) 陕西西安710068 中国富硒产业研究院陕西安康725000 长安大学地质工程与测绘学院陕西西安710054

【研究目的】人体日常摄入的硒主要通过食物链源于土壤,而中国是富硒土地资源相对匮乏的国家,面对有限且珍贵的富硒土地资源,亟需构建科学合理的富硒土地开发利用评价体系,为特色土地资源的高效开发提供依据。【研究方法】本文以陕西关... 详细信息

【研究目的】人体日常摄入的硒主要通过食物链源于土壤,而中国是富硒土地资源相对匮乏的国家,面对有限且珍贵的富硒土地资源,亟需构建科学合理的富硒土地开发利用评价体系,为特色土地资源的高效开发提供依据。【研究方法】本文以陕西关中地区为研究区,在土地质量地球化学调查成果基础上,融合反映农用地自然条件、基础设施水平的评价指标,构建了涵盖立地条件、土壤硒含量、理化性质、土壤质量和土地管理等5大类12项指标的关中地区富硒土地开发利用评价体系。同时以西安市临潼区为例,开展了临潼区富硒土地开发利用适宜性评价。【研究结果】将临潼区土地划分为高度适宜区、适宜区、较不适宜区、不适宜区和极不适宜区共5个等级,其中高度适宜开发区及适宜区开发面积共248.35 km^(2),主要分布在临潼区北部的新市乡、栎阳镇、徐杨乡、相桥镇及中东部的何寨镇。基于不同适宜评价区内小麦硒含量及富硒比例,发现其富硒土地适宜性与小麦富硒程度高度耦合。【结论】说明构建的富硒土地开发利用评价体系对富硒土地资源的开发利用具有较好的科学指导价值及重要的示范意义。

关键词：富硒土地开发利用评价体系农业地质调查工程临潼区关中地区

Treatment with β-sitosterol ameliorates the effects of cerebral ischemia/reperfusion injury by suppressing cholesterol overload, endoplasmic reticulum stress, and apoptosis

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Neural Regeneration Research 2024年第3期19卷 642-649页

作者： Xiuling Tang Tao Yan Saiying Wang Qingqing Liu Qi Yang Yongqiang Zhang Yujiao Li yumei Wu Shuibing Liu Yulong ma Le Yang Precision Pharmacy&Drug Development Center Department of PharmacyTangdu HospitalAir Force Medical UniversityXi’anShaanxi ProvinceChina Department of Clinical Pharmacy Jinling HospitalMedical School of Nanjing UniversityNanjingJiangsu ProvinceChina Department of Pharmacology School of PharmacyAir Force Medical UniversityXi’anShaanxi ProvinceChina Department of Anesthesiology The First Medical Center of Chinese PLA General HospitalBeijingChina Department of Anatomy Histology and Embryology and K.K.Leung Brain Research CentreAir Force Medical UniversityXi’anShaanxi ProvinceChina

β-Sitosterol is a type of phytosterol that occurs naturally in plants.Previous studies have shown that it has anti-oxidant,anti-hyperlipidemic,anti-inflammatory,immunomodulatory,and anti-tumor effects,but it is unknown whetherβ-sitosterol treatment reduces the effects of ischemic stroke.Here we found that,in a mouse model of ischemic stroke induced by middle cerebral artery occlusion,β-sitosterol reduced the volume of cerebral infarction and brain edema,reduced neuronal apoptosis in brain tissue,and alleviated neurological dysfunction;moreover,β-sitosterol increased the activity of oxygen-and glucose-deprived cerebral cortex neurons and reduced apoptosis.Further investigation showed that the neuroprotective effects ofβ-sitosterol may be related to inhibition of endoplasmic reticulum stress caused by intracellular cholesterol accumulation after ischemic stroke.In addition,β-sitosterol showed high affinity for NPC1L1,a key transporter of cholesterol,and antagonized its activity.In conclusion,β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.

关键词： apoptosis blood-brain barrier β-sitosterol cerebral ischemia/reperfusion injury cholesterol overload cholesterol transport endoplasmic reticulum stress ischemic stroke molecular docking NPC1L1