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Statistical Inferences in a Partially Linear Model with Autoregressive Errors

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Acta Mathematicae Applicatae Sinica 2022年第4期38卷 822-842页

作者： Xiao-hui liu yu WANG Ya-wen FAN yu-zi liu School of Statistics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang 330013China

In this paper,we consider the statistical inferences in a partially linear model when the model error follows an autoregressive process.A two-step procedure is proposed for estimating the unknown parameters by taking into account of the special structure in *** the asymptotic matrix of the estimator for the parametric part has a complex structure,an empirical likelihood function is also *** derive the asymptotic properties of the related statistics under mild *** simulations,as well as a real data example,are conducted to illustrate the finite sample performance.

关键词： partially linear model autoregressive errors two-step procedure profile empirical likelihood

Novel high-entropy oxides for energy storage and conversion:From fundamentals to practical applications

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Green Energy & Environment 2023年第5期8卷 1341-1357页

作者： zi-yu liu yu liu yujie Xu Hualiang Zhang Zongping Shao Zhenbin Wang Haisheng Chen Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China Nanjing Institute of Future Energy System Institute of Engineering ThermophysicsChinese Academy of SciencesNanjingChina University of Chinese Academy of Sciences Beijing100049China Curtin University Australia Department of Materials Science and Engineering City University of Hong KongKowloon999077Hong KongChina Dalian National Laboratory for Clean Energy Chinese Academy of SciencesDalian116023China

High-entropy oxides(HEOs)are gaining prominence in the field of electrochemistry due to their distinctive structural characteristics,which give rise to their advanced stable and modifiable functional *** review presents fundamental preparations,incidental characterizations,and typical structures of *** prospective applications of HEOs in various electrochemical aspects of electrocatalysis and energy conversion-storage are also summarized,including recent developments and the general trend of HEO structure design in the catalysis containing oxygen evolution reaction(OER)and oxygen reduction reaction(ORR),supercapacitors(SC),lithium-ion batteries(LIBs),solid oxide fuel cells(SOFCs),and so ***,this review notes some apparent challenges and multiple opportunities for the use of HEOs in the wide field of energy to further guide the development of practical *** influence of entropy is significant,and high-entropy oxides are expected to drive the improvement of energy science and technology in the near future.

关键词： High-entropy oxides Electrochemistry Energy storage and conversion

A Unit Root Test for an AR(1)Process with AR Errors by Using Random Weighted Bootstrap

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Acta Mathematica Sinica,English Series 2023年第9期39卷 1834-1854页

作者： Xiao Hui liu Ya Wen Fan yu zi liu Shi Hua Luo School of Statistics and Data Science Jiangxi University of Finance and EconomicsNanchang330013P.R.China Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang330013P.R.China

A great deal of economic problems are related to detecting the stability of time series data,where the main interest is in the unit root *** this paper,we consider the unit root testing problem with errors being long-memory processes with the LARCH structure.A new test statistic is developed by using the random weighted bootstrap *** turns out that the proposed statistic has a chisquared distribution asymptotically regardless of the process being stationary or nonst at ionary,and with or without an intercept *** simulation results show that the statistic has a desired finite sample performance in terms of both size and power.A real data application is also given relying on the inflation rate data of 17 countries.

关键词： Autoregressive model random weighted bootstrap autoregressive errors unit root test

Stable mechanical fixation in a bionic osteochondral scaffold considering bone growth

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Rare Metals 2022年第8期41卷 2711-2718页

作者： Jian Zhou Hao Huang Li-Jing Wang Maryam Tamaddon Chao-Zong liu zi-yu liu Teng-Bo yu Ying-Ze Zhang Department of Orthopaedic Surgery Qingdao Municipal HospitalQingdao UniversityQingdao266071China Department of Sports Medicine Affiliated Hospital of Qingdao UniversityQingdao266000China Division of Surgery&Interventional Science University College LondonRoyal National Orthopaedic HospitalLondonHA74LPUK School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China School of Engineering Medicine Beihang UniversityBeijing100191China

In the field of tissue engineering,there is significant subsidence of the porous design scaffold several months after *** avoid stress shielding and stimulate bone and cartilage ingrowth,high scaffold porosity is needed to diminish the mechanical properties of the *** closer the mechanical properties of the scaffold are to those of surrounding tissues,the better biological properties it will ***,adequate mechanical stability is needed as the scaffold needs to be well fixed in the target area and it will endure load after *** the mechanical fixation of the scaffold at the initial stage and the long-term performance of a scaffold for in vivo study is hard,as no facility can be put into the target area for the friction *** study investigated the mechanical stability of the biomimetic scaffold at the initial stage of implantation by finite element analysis(FEA).According to in vivo study,scaffold could not maintain its original position and would sink 1-2 mm in the target *** simulation results suggested that mechanical loading is not the main reason for scaffold subsidence.

关键词： Osteochondral scaffold Mechanical fixation Scaffold subsidence Bone ingrowth

Encapsulation of superparamagnetic Fe_3O_4@SiO_2 core/shell nanoparticles in MnO_2 microflowers with high surface areas

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Chinese Chemical Letters 2015年第2期26卷 233-237页

作者： yu-Gang Sun Tu T.Truong yu-zi liu Yong-Xing Hu Center for Nanoscale Materials Argonne National Laboratory

Microflowers made of interconnected MnO2 nanosheets have been successfully synthesized in a microwave reactor through a hydrothermal reduction of KMnO4 with aqueous HCI at elevated temperatures in the presence of superparamagnetic Fe3O4SiO2 core-shell *** to the chemical compatibility between SiO2 and MnO2,the heterogeneous reaction leads to the spontaneous encapsulation of the Fe3O4@SiO2 core-shell nanoparticles in the MnO2 *** resulting hybrid particles exhibit multiple properties including high surface area associated with the MnO2nanosheets and superparamagnetism originated from the Fe3O4@SiO2 core-shell *** are beneficial for applications requiring both high surface area and magnetic separation.

关键词： Microwave synthesis Manganese oxide nanosheets Superparamagnetic nanoparticles Hybrid nanostructures Multifunctional nanostructures

Trace nitrogen-doped hierarchical porous biochar nanospheres:Waste corn roots derived superior adsorbents for high concentration single and mixed organic dyes removal

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Nano Research 2023年第2期16卷 1846-1858页

作者： Lihua Wang Hongwei Li Mingyue Li Liyun Zhang Heng Zhang zi-yu liu Wancheng Zhu Department of Chemical Engineering Qufu Normal UniversityQufu 273165China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China

Seeking high performance adsorbents for highly efficient treatment of wastewater containing organic dyes has become increasingly imperative ***,with a specific surface area(SSA)of 2,745.4 m^(2)·g^(−1),trace N-doped porous biochar nanospheres(NPBs)are derived for the first time from affluent waste corn roots,via a hydrothermal conversion followed by a mild calcined activation by K2CO3(KC)in the presence of low virulent *** acts as N source and synergistic activator for significant promotion in SSA,pore volume,and surface *** obtained NPBs(CHC-0.5N-4KC-900)are confirmed as superior adsorbents for removal of organic dyes rhodamine B(RhB,qm=1,630.7 mg·g^(−1))and Congo red(CR,qm=1,766.2 mg·g^(−1))as well as their mixtures,within not only a low(50,esp.250–1500 mg·L^(−1))concentration *** values for qm are far beyond commercially activated carbon(AC)as well as most reported biomass derived carbons,undoubtedly revealing the NPBs as great promising candidate adsorbents for disposal of real industrial *** addition,the adsorption of RhB is fitted by Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm *** kinetic analysis indicates that the adsorption before equilibrium conforms to the pseudo-second-order model,and the hydrogen bonding,electrostatic attraction,and esp.π–πinteraction have contributed to the superior adsorption performance of the NPBs.

关键词： biomass corn roots N-doped carbons biochar organic dyes adsorption

Tautening effect mechanism of titanium-alloy InterTAN nail

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Rare Metals 2023年第12期42卷 4226-4233页

作者： Xiang-Sheng Gao Sheng-Kai Ma Wang-Ao-Ran Chen Min Wang Qi Pan zi-yu liu Beijing Key Laboratory of Advanced Manufacturing Technology Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China The Fourth People's Hospital of Jinan Jinan 250031China School of Engineering Medicine Beihang UniversityBeijing 100191China Division of Surgery&Interventional Science University College LondonRoyal National Orthopaedic HospitalLondon HA74LPUK

Although InterTAN(IT)nails are widely employed to treat femoral intertrochanteric fractures,the mechanism behind the tautening effect of titanium-alloy IT nails is not well *** study aimed to reveal the mechanism of this effect.A torque test experiment was conducted,with the torque value recorded and transformed to obtain the tautening ***,theoretical and finite element analyses were performed to further understand the *** influence of age and pitch-difference on the tautening effect was also examined in the study,the results attributed to the pitch-varying integrated interlocking lag *** torque and the corresponding tautening effect drastically increase as the screw is inserted deeper during the second stage,while the torque measured in the first stage is always ***,the tautening force increases with increasing age,this relationship helps evaluate the effect at different *** tautening effect also increases nearly linearly with the pitch difference,which can be adjusted during the IT design stage to select or design IT in engineering practice.

关键词： Tautening effect InterTAN nail Finite element analysis Torque

Detection and formation mechanism of micro-defects in ultrafine pitch Cu-Cu direct bonding

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Chinese Physics B 2016年第1期25卷 802-808页

作者：刘子玉蔡坚王谦陈瑜 Institute of Microelectronics Tsinghua UniversityBeijing 100084China Tsinghua National Laboratory for Information Science and Technology Beijing 100084China

In this paper, Cu-Cu interconnects with ultrafine pad pitches of 6 p.m, 8 p.m, and 15 p.m are implemented on the 12 inch wafers by a direct bonding process. Defects are not found by traditional non-destructive （NDT） c-mode scanning acoustic microscopy （c-SAM）. However, cross sectional observation of bonding interfaces reveals that micro-defects such as micro seams are located at SiO2 bonding interfaces. In order to examine the micro-defects in the ultra-fine pitch direct bonding process by the NDT technology, a novel ＂defect-enlarged approach＂ is proposed. The bonded dies are first annealed in an N2 oven at 300 ℃ for a few hours and then cooled quickly in air. The c-SAM scanning images show large defects at the place where nothing can be detected by c-SAM before this treatment. Cross sectional observation of the bonding interfaces indicates that these defects consist of large size micro seams at the SiO2 bonding interface, especially near Cu pads with an ultrafine pitch of 6μm. However, these large defects disappear after several hours at room temperature, observed by c-SAM. It is inferred that the disappearance of these defects inspected by the ＂defect-enlarged approach＂ results from the combination of intrinsic micro seams and ＂weak＂ bonds in the silicon oxide layer. Then the underlying physical mechanism of these micro-defects is proposed, which is influenced by Cu pad surface topology and bonding models.

关键词： nondestructive testing of materials microscopy acoustical surface and interface

World Journal of GastroenterologyDevelopment and validation of a risk prediction score for the severity of acute hypertriglyceridemic pancreatitis in Chinese patients

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World Journal of Gastroenterology 2022年第33期28卷 4846-4860页

作者： zi-yu liu Lei Tian Xiang-Yao Sun Zong-Shi liu Li-Jie Hao Wen-Wen Shen Yan-Qiu Gao Hui-Hong Zhai Department of Gastroenterology Xuanwu HospitalCapital Medical UniversityBeijing 100053China Department of Hematology and Hematopoietic Cell Transplantation City of Hope National Medical CenterLos AngelesCA 91010United States Department of Orthopedics Xuanwu HospitalCapital Medical UniversityBeijing 100053China Department of Geriatric Guangzhou First People's HospitalSchool of MedicineSouth China University of TechnologyGuangzhou 510180Guangdong ProvinceChina

BACKGROUND The frequency of acute hypertriglyceridemic pancreatitis(AHTGP) is increasing worldwide. AHTGP may be associated with a more severe clinical course and greater mortality than pancreatitis caused by other causes. Early identification of patients with severe inclination is essential for clinical decision-making and improving prognosis. Therefore, we first developed and validated a risk prediction score for the severity of AHTGP in Chinese *** To develop and validate a risk prediction score for the severity of AHTGP in Chinese *** We performed a retrospective study including 243 patients with AHTGP. Patients were randomly divided into a development cohort(n = 170) and a validation cohort(n = 73). Least absolute shrinkage and selection operator and logistic regression were used to screen 42 potential predictive variables to construct a risk score for the severity of AHTGP. We evaluated the performance of the nomogram and compared it with existing scoring systems. Last, we used the best cutoff value(88.16) for severe acute pancreatitis(SAP) to determine the risk stratification *** Age, the reduction in apolipoprotein A1 and the presence of pleural effusion were independent risk factors for SAP and were used to construct the nomogram(risk prediction score referred to as AAP). The concordance index of the nomogram in the development and validation groups was 0.930 and 0.928, respectively. Calibration plots demonstrate excellent agreement between the predicted and actual probabilities in SAP patients. The area under the curve of the nomogram(0.929) was better than those of the Bedside Index of Severity in AP(BISAP), Ranson, Acute Physiology and Chronic Health Evaluation(APACHE II), modified computed tomography severity index(MCTSI), and early achievable severity index scores(0.852, 0.825, 0.807, 0.831 and 0.807, respectively). In comparison with these scores, the integrated discrimination improvement and decision curve ana

关键词： Nomogram Severity Acute pancreatitis Prediction model