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Abdominal pain among children re-evaluation of a diagnostic algorithm

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World Journal of Gastroenterology 2002年第5期8卷 947-951页

作者： zhou, h Chen, YC Zhang, JZ Capital Univ Med Sci Beijing Childrens Hosp Dept Pediat Surg Beijing 100045 Peoples R China

AIM: To re-evaluate the algorithm that has been used forover 40 years for diagnosis of acute abdominal pain ***: Among the 937 cases admitted to the surgicalemergency ward in 2000, 656 cases of acute appendicitiswere studied to evaluate the usefulness of the presentalgorithm for its colculated accuracy, false positive and falsenegative rates, the sensitivity and specificity in the instantdiagnosis of various types of acute appendicitis in differentage *** algorithm used was established in 1958and revisedror this study in 1999. It includes a 3-step analysisof clinical presentations, i.e.: firstly, a diagnosis of surgicalpain by definite organic abdominal signs; then a diagnosisof the subgroup of surgical condition by special signs; andfinally the diagnosis of the present disease by specific signs.A footnote describes a 'comparative technique″ of abdominalexamination in non-cooperative ***: The general accuracy of diagnosis was 92.8 %,overall mortality 0.1% among 973 cases of abdominal painin 2000. 373 attending surgeons and 241 residents includingtrainees joined the diagnosis and treatment with noremarkable difference in the results. The incidence of acuteappendicitis, 656 in 973 cases, was 67.4 % representingthe majority of abdominal pain. In the series of 656 cases,the accuracy of diagnosis of acute appendidtis was 93.6 %,false positive 6.4 %, false negative 0.9 %, sensitivity at firstvisit 82.7 %, specificity for appendicitis 98.0 %, no death ordocumentary ***: The present algorithm used for diagnosisof acute abdominal pain is effective and preferable inreducing misdiagnosis and maltreatment at emergency. Theuse of some modern technology should be further explored.

关键词：儿童腹痛鉴别诊断病因

ON ThE DYNAMIC ChARACTERISTICS OF MOULD-FILLING UNDER COUNTERGRAVITY

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 409-414页

作者： Zeng, J.M. Gu, h. zhou, Y.h. Guangxi Univ Nanning China

In this paper, the mathematical models for mould-filling under countergravity are derived on the basis of the principle of momentum. Dynamic processes of mould-filling are observed on a perspex model by means of high speed photography. The results indicate that the mould-filling under countergravity can be described by the second order nonlinear differential equations characterized by damping oscillations. The velocity oscillations amplify as the pressuring speed increases if the pressure differential functions are of the same type. On the other hand, if the functions are of different type, then the velocity oscillations depend upon whether the functions progressively increase or decrease. Velocity oscillations can be diminished dramatically by increasing the local damping within the gating system.

关键词： casting mould-filling dynamics

Asymptotically efficient parameter estimation for ordinary differential equations

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Science China Mathematics 2017年第11期60卷 2263-2286页

作者： PANG TianXiao YAN PeiSi zhou harrison h. School of Mathematical Sciences Zhejiang University Center for Computing and Visualization Brown University Department of Statistics and Data Science Yale University

Parameter estimation for ordinary differential equations arises in many fields of science and engineering. To be the best of our knowledge, traditional methods are often either computationally intensive or inaccurate for statistical inference. Ramsay et al.(2007) proposed a generalized profiling procedure. It is easily implementable and has been demonstrated to have encouraging numerical performance. however, little is known about statistical properties of this procedure. In this paper, we provide a theoretical justification of the generalized profiling procedure. Under some regularity conditions, the procedure is shown to be consistent for a broad range of tuning parameters. When the tuning parameters are sufficiently large, the procedure can be further shown to be asymptotically normal and efficient.

关键词： asymptotic efficiency consistency generalized profiling procedure ordinary differential equations splines

Three-dimensional structure of the inner core of rice dwarf virus

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Science China(Life Sciences) 2001年第2期44卷 192-198页

作者：邵承华 Z.h.zhou 卢光莹 National Laboratory of Protein Engineering and Plant Genetic Engineering College of Life Sciences Peking University Beijing China Department of Pathology and Laboratory Medicine Houston Medical School University of Texas Houston USA

Rice dwarf virus (RDV) is a double-shelled icosahedral virus. Using electron cryomicro-scopy and computer reconstruction techniques, we have determined a 3.3 nm resolution three-dimensional (3D) structure of the inner shell capsid without the outer shell and viral RNA. The results show that the inner shell is a thin, densely packed, smooth structure, which provides a scaffold for the full virus. A total of 120 copies of the major inner shell capsid protein P3 forms 60 dimers arranged in a T=1 icosahedral lattice. A close examination on the subunit packing of the T=1 inner core P3 with that of the T=13/ outer shell P8 indicated that P8 trimers connect with P3 through completely non-equivalent, yet highly specific, intermolecular interactions.

关键词： rice dwarf virus inner core three-dimensional structure.

INFLUENCE OF FIBER COATING ON TENSILE BEhAVIOR OF UNIDIRECTIONAL C/Mg COMPOSITES

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 398-402页

作者： Zhang, K. Wang, Y.Q. zhou, B.L. zhou, Y.h. Li, h.L. Inst of Metal Research Chinese Acad of Sciences Shenyang China

The mechanical properties and deformation mechanisms of unidirectional carbon fiber reinforced magnesium composites under tensile loading are studied. Two different materials are used as fiber coatings: a single silica and a gradient C/SiC/SiO[sb 2]. The results show that, under the same preparation conditions, composite with the former coating is broken in a non-cumulative mode and its failure stress is rather low. Conversely, the latter coating demonstrates much better efficiency and the corresponding composite is broken in a cumulative mode.

关键词： Metallic matrix composites Carbon fibers Tensile strength Elastic moduli Coatings Silica Deformation Crack propagation Crack initiation Fracture Stresses Strain

PREDICTION OF ThE MIXING ENThALPIES OF BINARY LIQUID ALLOYS BY MOLECULAR INTERACTION VOLUME MODEL

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 336-340页

作者： h.W. Yang D.P. Tao Z.h. zhou Faculty of Materials and Metallurgical Engineering Kunming University of Science and Technology Kunming 650093 China

The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model （MIVM）, which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted va... 详细信息

关键词： Molecular interaction volume model Mixing enthalpy Liquid alloys Prediction

SOLIDIFICATION MEChANISM OF UNDERCOOLEDSINGLE PhASE ALLOYS

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Acta Metallurgica Sinica(English Letters) 1998年第2期11卷 100-106页

作者： J.F.Li G.C.Yang Y.h.zhou Northwestern Polytechnical Univ Xi'an China

The solidification behavior of bulk undercooled Ni50Cu50 alloy was systematically investigated. Double recalescences were discovered for the first time in a single phase Ni-Cd alloy, in which there is no solid phase transition at elevated temperature. When the alloy melt was undercoolcd below the solidus temperature, the effect of nonequilibrium solidification could make the solid with the norminal composition C0 of the alloy nucleate and grow till tempemture approached To (the temperuture at which the free enengies of solid and liquid with C0 are equal). Following it, the nucleation and growth of the solid with more high melting point component were required, so the secondary recalescence took place. The concentration distribution in crystals was also analysed.

关键词： undercooled Ni-Cu alloy secondary recalescence solidification mechanism

Effect of the span of Australian GPS coordinate time series in establishing an optimal noise model

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Science China Earth Sciences 2015年第11期58卷 523-539页

作者： JIANG WeiPing zhou Xiaohui GNSS Research Center Wuhan University School of Geodesy and Geomatics Wuhan University

The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System （GPS） sites from 1998.0 to mid-2009 on the Australian Plate to estimate the best noise model and thereafter obtain the true uncertainties of the velocity, employing the maximum likelihood estimation （MLE） method. MLE was employed to analyze the data in four ways. In the first two analyses, the noise was assumed to be a combination of flicker noise and white noise for the raw time series and spatially filtered time series. In the final two analyses, the spectral indices and amplitudes were simultaneously estimated for a power law noise plus white noise model for the raw time series and spatially filtered time series. We conclude that the noise model of GPS time series in Australia can be best described as the combination of flicker noise and white noise. Velocity uncertainties fall below -0.2 mm/yr when the time span exceeds -9.5 years. A comparison of noise amplitudes and maximum likelihood estimation values between the raw and spatially filtered time series suggests that traditional spatial filtering to remove common-mode errors might not be applicable to the raw time series of this region.

关键词： Australian Plate Global Positioning System time series noise model maximum likelihood estimation

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Microstructure and Mechanical Properties of Fe-based Amorphous Composite Coatings Reinforced by Stainless Steel Powders

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Journal of Materials Science & Technology 2015年第1期31卷 43-47页

作者： h.zhou C.Zhang W.Wang M.Yasir L.Liu School of Materials Science and Engineering State Key Lab for Materials Processing and Die &Mould TechnologyHuazhong University of Science and Technology huazhong University of Science and Technology Research Institute in Shenzhen

In this study,a few Fe-based amorphous matrix composite coatings reinforced with various portions(4,8 and16 vol.%) of 31 6L stainless steel powders have been successfully produced through high velocity oxy-fuel(hVOF) *** microstructure of the composite coatings was systematically characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The main structure of composite coatings remained amorphous while 31 6L stainless steel splats were distributed homogeneously in the amorphous matrix and well connected with surrounding amorphous *** strength of coatings to the substrate was determined by 'pull-off' tensile *** results revealed that the31 6L stainless steel phase effectively improved the bonding strength of amorphous coatings,which is mainly contributed by the strong metallurgical bonding between stainless steel and amorphous *** addition of31 6L stainless steel also enhanced the ductility and fracture resistance of the coatings due to the ductile stainless steel phases,which can arrest crack propagation and increase energy dissipation.

关键词： Thermal spraying Fe-based amorphous coating Stainl