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Variable selection via quantile regression with the process of Ornstein-Uhlenbeck type

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Science China Mathematics 2022年第4期65卷 827-848页

作者： Yinfeng Wang xinsheng zhang School of Statistics and Mathematics Shanghai Lixin University of Accounting and FinanceShanghai201209China Department of Statistics Fudan UniversityShanghai200433China

Based on the data-cutoff method,we study quantile regression in linear models,where the noise process is of Ornstein-Uhlenbeck type with possible jumps.In single-level quantile regression,we allow the noise process to be heteroscedastic,while in composite quantile regression,we require that the noise process be homoscedastic so that the slopes are invariant across quantiles.Similar to the independent noise case,the proposed quantile estimators are root-n consistent and asymptotic normal.Furthermore,the adaptive least absolute shrinkage and selection operator(LASSO)is applied for the purpose of variable selection.As a result,the quantile estimators are consistent in variable selection,and the nonzero coefficient estimators enjoy the same asymptotic distribution as their counterparts under the true model.Extensive numerical simulations are conducted to evaluate the performance of the proposed approaches and foreign exchange rate data are analyzed for the illustration purpose.

关键词： adaptive LASSO composite quantile regression data-cutoff method process of Ornstein-Uhlenbeck type quantile regression

Investigation of photoelectrocatalytic degradation mechanism of methylene blue by a-Fe_(2)O_(3) nanorods array

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Chinese Journal of Chemical Engineering 2023年第5期57卷 162-172页

作者： Yaqiao Liu Shuozhen Hu xinsheng zhang Shigang Sun State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.

关键词： a-Fe_(2)O_(3)nanorods array Methylene blue Photoelectrocatalytic degradation mechanism Free radicals Photo-generated holes

NbN quantum dots anchored hollow carbon nanorods as efficient polysulfide immobilizer and lithium stabilizer for Li-S full batteries

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Journal of Energy Chemistry 2024年第1期88卷 260-271,I0007页

作者： Fei Ma Zhuo Chen Katam Srinivas Ziheng zhang Yu Wu Dawei Liu Hesheng Yu Yue Wang xinsheng Li Ming-qiang Zhu Qi Wu Yuanfu Chen School of Integrated Circuit Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and TechnologyChengdu 610054SichuanChina College of Science and Institute of Oxygen Supply Center of Tibetan Studies(Everest Research Institute)Tibet UniversityLhasa 850000TibetChina College of Mechanical and Electronic Engineering Northwest A&F UniversityXianyang 712100ShaanxiChina

The shuttle effect of lithium polysulfides(LiPSs)and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur(Li-S)batteries.To simultaneously address such issues,monodispersed Nb N quantum dots anchored on nitrogen-doped hollow carbon nanorods(NbN@NHCR)are elaborately developed as efficient Li PSs immobilizer and Li stabilizer for high-performance Li-S full batteries.Density functional theory(DFT)calculations and experimental characterizations demonstrate that the sulfiphilic and lithiophilic NbN@NHCR hybrid can not only efficiently immobilize the soluble Li PSs and facilitate diffusion-conversion kinetics for alleviating the shuttling effect,but also homogenize the distribution of Li+ions and regulate uniform Li deposition for suppressing Li-dendrite growth.As a result,the assembled Li-S full batteries(NbN@NHCR-S||Nb N@NHCR-Li)deliver excellent long-term cycling stability with a low decay rate of 0.031%per cycle over 1000 cycles at high rate of 2 C.Even at a high S loading of 5.8 mg cm^(-2)and a low electrolyte/sulfur ratio of 5.2μL mg^(-1),a large areal capacity of 6.2 mA h cm^(-2)can be achieved in Li-S pouch cell at 0.1 C.This study provides a new perspective via designing a dual-functional sulfiphilic and lithiophilic hybrid to address serious issues of the shuttle effect of S cathode and dendrite growth of Li anode.

关键词： Dual-functional host NbN quantum dots Shuttle effect Dendrite-free Li anode Li-S full batteries

Applied biodiversity science in China in the global context

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National Science Review 2021年第7期8卷 62-65页

作者： Thomas M.Brooks xinsheng zhang International Union for Conservation of Nature

In 2021, the city of Kunming in Yunnan Province, China,will host the fifteenth meeting of Conference of Parties of the Convention on Biological Diversity. The meeting is expected to be the pivotal moment at which the world’s governments agree on a new ‘Post-2020 Global Biodiversity Framework’(https://www.***.int/conferences/post2020). The framework is anticipated to be structured around a small number of outcome goals for 2050—a compelling case has been made that these should include explicit goals for ecosystems, species,genetic diversity and the contributions which nature makes to people [1].

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Positive direction of polarization-induced electric field improves formic acid electrooxidation on Pd

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Nano Research 2023年第8期16卷 10848-10856页

作者： Shuozhen Hu Yunyun Cheng Guoming Luo Kai Huang Cheng Shi Jie Xu Cheng Lian Shigang Sun xinsheng zhang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Shanghai Hydrogen Propulsion Technology Co. Ltd.Shanghai 201800China Shanghai Haizhiqing Energy Development Co. Ltd.Shanghai 200333China Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education Functional Materials Research LaboratorySchool of Materials Science and EngineeringTongji UniversityShanghai 201804China School of Materials Science and Engineering Anhui University of TechnologyMa’anshan 243002China State Key Laboratory of Physical Chemistry of Solid Surfaces Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-induced electric field(PIEF)with different directions,to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd.Tourmaline nanoparticles are applied as the PIEF provider,of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field.Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd,reduced adsorption energy of COad,enhanced adsorption energy of*HCOOH and*OH,and promoted formate pathway of formic acid electrooxidation.Pd/TNP+/FTO,with the aid of positive PIEF,shows three-fold enhancement in the formic acid electrooxidation(4.74 mA·cm^(−2))with high durability and anti-poisoning ability compared with pristine Pd.This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field.

关键词： dipole-aligned tourmaline ferroelectric material polarization-induced electric field direction palladium adsorption energy formic acid oxidation mechanism

Goji berry-derived phenylpropionyl phenylethylamine derivatives protect against ethanol-induced hepatic damage

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Food Science and Human Wellness 2024年

作者： Zhengqun Zhou Zhaodi Che Jiancong Mai Rui zhang Zhihui Luo Yifang Li Kwokfai So Jia Xiao xinsheng Yao Hao Gao GMH Institute of CNS Regeneration Guangdong Medical Key Laboratory of Brain Function and Diseases Jinan University Clinical Medicine Research Institute and Department of Metabolic and Bariatric Surgery the First Affiliated Hospital of Jinan University Institute of Traditional Chinese Medicine and Natural Products College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China Jinan University

Goji berry is a famous edible and medicinal substance around the world. In this research， 15 phenylpropionyl phenylethylamine derivatives (1-15)， including one new compound (1)， were separated and identified from goji berry. All isolates were elucidated via extensive NMR spectral analyses and chemical techniques. Six known isolates were first obtained from Lycium genus. Six isolates were effectively split into double chromatographic peaks accompanied by the basically identical areas， indicating they belong to racemates. The ORAC experiment indicated that all isolates displayed a capacity of scavenging free radicals， and most of them exhibited higher ORAC values than EGCG. In ethanol/palmitic acid (PA)-established in vitro hepatocyte injury model， four phenylpropionyl phenylethylamine derivatives (1， 2， 9， and 15) significantly alleviated hepatocyte injury， among which compound 1 exerted the strongest protective activity. Notably， the hepatoprotective effect of compound 1 was further confirmed in ethanol-established liver damage mouse model， reflected by the reduction of lipid accumulation and the attenuation of pathological alteration. Combined with the in vitro results， the in vivo observations suggested that compound 1 suppressed cell apoptosis and the outburst of inflammation. Our findings provided first-hand evidence proving that goji berry-derived phenylpropionyl phenylethylamine derivatives hold a potential in treating alcoholic liver disease.

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融合时空特征的GCN-LSTM西北地区沙尘天气预测模型研究

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干旱区资源与环境 2024年第5期38卷 111-120页

作者：苏佳李高雅张新生西安建筑科技大学管理学院西安710055

针对以往沙尘天气预测算法中时空特征提取不足的问题,文中提出一种基于融合时空特征的图卷积和长短期记忆网络(GCN-LSTM)的沙尘天气预测模型。以西北地区为研究对象,利用城市之间的植被指数和距离构建邻接矩阵,通过图卷积网络(GCN)对空... 详细信息

针对以往沙尘天气预测算法中时空特征提取不足的问题,文中提出一种基于融合时空特征的图卷积和长短期记忆网络(GCN-LSTM)的沙尘天气预测模型。以西北地区为研究对象,利用城市之间的植被指数和距离构建邻接矩阵,通过图卷积网络(GCN)对空间特征、长短期记忆网络(LSTM)对时间特征进行提取,将特征融合后用于预测各个城市的沙尘天气。与GCN、LSTM、时空因果卷积神经网络(STCN)模型相比,文中提出的GCN-LSTM模型的准确率分别提高6%、8%、2%,且其接收者操作特征曲线(ROC)、ROC曲线下的面积(AUC)、精确度-召回度曲线(P-R)评价指标表现更优。文中研究为沙尘天气发生采取防范措施、减少损失提供借鉴意义。

关键词：沙尘天气预测图卷积网络长短期记忆网络时空特征

双有源桥DC-DC变换器三移相调制及其死区效应分析和补偿

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电工技术学报 2024年第6期39卷 1907-1922页

作者：康薇肖飞任强王瑞田张新生海军工程大学舰船综合电力技术国防科技重点实验室武汉430033

针对双有源桥(DAB)变换器宽电压范围应用,该文研究一种全工况连续、表达形式统一、计算量小的三移相(TPS)调制策略,并分析其功率传输特性及软开关性能。结合工程应用中的非理想因素,对TPS调制不同开关模式下的死区效应及其边界进行研究... 详细信息

针对双有源桥(DAB)变换器宽电压范围应用,该文研究一种全工况连续、表达形式统一、计算量小的三移相(TPS)调制策略,并分析其功率传输特性及软开关性能。结合工程应用中的非理想因素,对TPS调制不同开关模式下的死区效应及其边界进行研究,给出DAB宽电压范围运行时避免电压跌落和极性反转的约束条件。针对死区引入的移相比损失、软开关范围减小等问题,提出一种基于开关脉冲调整的死区补偿策略以补偿移相比损失,重新获取全工况软开关范围,降低死区引入的附加电流应力及损耗、提升效率。最后通过仿真和实验验证所提策略的有效性。

关键词：双有源桥变换器宽电压范围运行三移相(TPS)调制死区效应死区补偿

长时间序列生态系统服务权衡与协同驱动因素——以芜湖市生态系统服务功能极重要区为例

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生态学报 2024年第5期44卷 1780-1790页

作者：刘颂张浩鹏裴新生王颖同济大学建筑与城市规划学院上海200092 上海同济城市规划设计研究院有限公司上海200092

人类对生态系统的管理和干预促使生态系统服务权衡向协同转化,有助于生态系统服务综合效益提升。但当前缺乏对长时间序列分析背景下生态系统服务权衡协同驱动因素及其非线性影响的理解与把握。以芜湖市“生态系统服务功能极重要区”为... 详细信息

人类对生态系统的管理和干预促使生态系统服务权衡向协同转化,有助于生态系统服务综合效益提升。但当前缺乏对长时间序列分析背景下生态系统服务权衡协同驱动因素及其非线性影响的理解与把握。以芜湖市“生态系统服务功能极重要区”为研究案例,考虑生境质量、碳固定和土壤保持三种关键生态系统服务,基于多源数据,运用逐像元趋势叠加分析法评估1990—2020年间研究区生态系统服务变化趋势及其权衡协同空间分布规律,采用随机森林模型探索该区域生态系统服务权衡协同形成的关键驱动因素及其非线性影响效应。研究结果表明:(1)31年间芜湖市域生境质量显著下降区域面积约为提升面积的两倍,存在进一步衰退的风险。同时,城市扩张导致市郊边缘地带碳固定、土壤保持显著下降。(2)研究区生态系统服务供给能力受权衡协同影响显著,受影响区域总面积占比达64.48%。受权衡影响区域与协同影响区域存在显著空间差异。(3)土地利用强度是管理生态系统服务权衡向协同转化的主导因素。土地利用强度对权衡协同的影响表现出非线性特征并且存在影响阈值。当强度等级介于弱与中且偏向弱强度时对不同服务协同增益具有积极作用。

关键词：长时间序列生态系统服务权衡与协同驱动因素随机森林