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Microstructural evolution and mechanical properties of thixoformed A319 alloys containing variable amounts of magnesium

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Transactions of Nonferrous Metals society of China 2016年第8期26卷 2029-2042页

作者： M.s.sALLEH M.Z.OMAR K.s.ALHAWARI M.N.MOHAMMED M.A.MAD ALI E.MOHAMAD Department of Manufacturing Process Faculty of Manufacturing Engineering Universiti Teknikal Malaysia Melaka Department of Mechanical and Materials Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia Department of Engineering and Technology Faculty of Information Sciences and EngineeringManagement and Science University

The effects of Mg content on the microstructure and tensile properties of thixoformed A319 alloys were studied. The samples were thixoformed at 50% liquid content and some of the thixoformed samples were subjected to the T6 heat treatment. The samples were then examined by optical microscopy (OM), scanning electron microscopy (sEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analysis as well as tensile tests. The results showed that magnesium was able to refine the eutectic silicon in the samples. It was also observed that a compact Al9FeMg3si5 phase was formed when the magnesium content was 1.0% and 1.5%. The results also revealed that as the magnesium content in the alloy increases, the tensile strengths of the thixoformed alloys also increase. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed A319 heat treated alloy were 298 MPa, 201 MPa and 4.5%, respectively, whereas the values of the thixoformed heat treated alloy with 1.5% Mg content were 325 MPa, 251 MPa and 1.4%, respectively. Thixoformed A319 alloy showed a dimple fracture behaviour, while thixoformed A319 alloys with 1.5% Mg showed a mixed mode fracture behaviour, where dimple and cleavage ruptures were seen on the fracture surface of the samples.

关键词： aluminium alloy thixoforming T6 heat treatment mechanical properties

A Theoretical Test of the Geostrophic Momentum Approximation

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Advances in Atmospheric sciences 1992年第2期9卷 251-255页

作者： T.s.spassova Institute of Meteorology and Hydrology Bulgarian Academy of Sciences Sofia previously developed model of a 2-dimensional air flow with constant horizontal shear is used to estimeate the accuracy of the geostrophic momentum approximation by comparison of exact solutions when exist with approximate ones.

A previously developed model of a 2-dimensional air flow with constant horizontal shear is used to estimeate the accuracy of the geostrophic momentum approximation by comparison of exact solutions when exist with appr... 详细信息

关键词： Horizontal Wind Velocity Elliptic Paraboloid Wind Velocity Vector Geopotential Field Elliptic Vortex

Understanding of performance degradation of LiNi0.80Co0.10Mn0.10O2 cathode material operating at high potentials

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Journal of Energy Chemistry 2020年第2期29卷 135-141页

作者： sheng sZhang Electrochemistry Branch FCDD-RLS-DCSensors and Electron Devices DirectorateU.S.Army Research LaboratoryAdelphiMD 20783-1138USA

Inferior cycling stability, poor safety, and gas generation are long lasting problems of Ni-rich Li Ni0.80 Co0.10 Mn0.10 O2(NCM811) cathode material. Although much effort has been made, mechanisms for the above problems are poorly understood. studying the cycling and float-charging characteristics of Li/NCM811 cells in high voltage conditions(4.5 V and 4.7 V, respectively), in this work we find that nearly all known problems with NCM811 material can be attributed to the oxidation of lattice oxygen occurring in the capacity region corresponding to H2 → H3 phase transition. While contributing to overall capacity,the oxidation of lattice oxygen results in a loss of oxygen through oxygen evolution and relative reactions between active oxygen evolution intermediates and electrolyte solvents. It is the loss of oxygen that results in irreversible layered-spinel-rocksalt phase transition, secondary particle cracking, and performance degradation. The conclusions of this work suggest that the priority for further research on NCM811 material should give to the suppression of oxygen evolution, followed by the use of the anti-oxygen electrolyte being chemically stable against the active oxygen evolution intermediates.

关键词： Ni-rich cathode Lattice oxygen Phase transition Oxygen evolution Performance degradation

Neoadjuvant chemoradiation is associated with decreased lymph node ratio in borderline resectable pancreatic cancer:A propensity score matched analysis

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Hepatobiliary & Pancreatic Diseases International 2021年第1期20卷 74-79页

作者： June s Peng Gareth Morris-stiff Noaman s Ali Jane Wey sricharan Chalikonda Kevin M El-Hayek R Matthew Walsh Department of surgery The Pennsylvania State UniversityCollege of MedicineHersheyPA 17033-0850USA Department of General surgery Digestive Disease and Surgery InstituteCleveland Clinic FoundationClevelandOH 44195-0001USA

Background:Lymph node ratio(LNR)and margin status have prognostic significance in pancreatic *** we examined the pathologic and clinical outcomes in patients with borderline resectable pancreatic cancer(BRPC)following neoadjuvant therapy(NAT)and ***:Patients who underwent treatment between January 1,2012 and June 30,2017 were *** patients in the BRPC group were compared to a propensity score matched cohort of patients with radiographically resectable pancreatic cancer who underwent upfront surgical *** BRPC group was also compared to sequential patients with radiographically resectable pancreatic cancer who required vein resection(VR)during upfront ***:There were 50 patients in the BRPC group,50 patients in the matched control group,and 38 patients in the VR *** margins(R0)were seen in 72%,64%,and 34%of the BRPC,control,and VR groups,respectively(P=0.521 for BRPC ***;P=0.002 for BRPC ***),with 24%of the BRPC group requiring a vascular *** stage was N0 in 64%,20%,and 18%of the BRPC,control,and VR groups,respectively(Pstatus was stratified into four groups(N0,or LNR≤0.2,0.2–0.4,≥0.4),the BRPC group had a more favorable distribution(Psurvival were 28.8,38.6,and 19.0 months for the BRPC,control,and VR groups,respectively(log-rank P=0.096).Conclusions:NAT in BRPC was associated with more R0 and N0 resections and lower LNR compared to patients undergoing upfront resection for resectable disease.

关键词： Neoadjuvant therapy Lymph node ratio Pancreatic cancer Borderline resectable Vein resection

sCORE LIsTs IN(h,k)-BIPARTITE HYPERTOURNAMENTs

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Applied Mathematics(A Journal of Chinese Universities) 2007年第4期22卷 485-489页

作者： Pirzada s Zhou Guofei Dept. of Math. University of Kashmir India. Dept. of Math. Nanjing University Nanjing 210093. China.

Given non-negative integers m,n,h and k with m≥ h 〉 1 and n ≥ k 〉 1, an （h, k）-bipartite hypertournament on m ＋ n vertices is a triple （U, V, A）, where U and V are two sets of vertices with ｜U｜ = m and ｜V｜ = n, and A is a set of （h ＋ k）-tuples of vertices,called arcs, with at most h vertices from U and at most k vertices from V, such that for any h＋k subsets U1 UV1 of UUV, A contains exactly one of the （h＋k）! （h＋k）-tuples whose entries belong to U1 ∪ V1. Necessary and sufficient conditions for a pair of non-decreasing sequences of non-negative integers to be the losing score lists or score lists of some（h, k）-bipartite hypertournament are obtained.

关键词： score list hypertournament.

ATP细胞活力试验在测量宫颈癌固有放射敏感性中的应用前景

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世界核心医学期刊文摘（妇产科学分册） 2005年第7期1卷 37-38页

作者： tam K.F. Ng T.Y. 郭慧方 Dept. of Obstetrics and Gynaecology University of Hong Kong Queen Mary Hospital 102 Pokfulam Road Hong Kong Hong Kong

Background. Intrinsic radiosensitivity using the clonogenic assay and the cell surviving fraction at 2 Gy (sF2) has been shown to be an independent prognostic factor for patient response to radiotherapy in carcinoma of the cervix. The clonogenic assay has significant shortcomings, making it unsuitable for routine clinical use. The ATP cell viability assay (ATP- CVA) has been shown to have a high tumor evaluability rate, technical simplicity, and reproducibility in chemosensitivity testing. Aims. This study compares the ATP- CVA with the clonogenic assay in the in vitro radiosensitivity testing of cervical cancer cell lines. Correlation of in vitro radiosensitivity and in vivo patient response was also determined. Methods. Five cervical carcinoma cell lines (siHa, HeLa, Caski, C- 33A, and C4- 1) were tested using the ATP- CVA and the clonogenic assay. survival curves were plotted and the mean sF2 values obtained by the two different assay methods were compared using ANOVA to see if there were significant differences. Mean sF2 values obtained from 27 cervical cancers were compared with clinical outcomes. Results. The sF2 values for the cell lines ranged from 0.28 to 0.67 when tested using the ATP- CVA. Using the clonogenic assay, the sF2 values ranged from 0.27 to 0.70. ANOVA with Bonferroni pairwise multiple comparison showed no significant difference between the mean sF2 values for the individual cell lines between the two assay methods. Twenty- three cervical cancer samples (85% ) were evaluable for sF2 using ATP- CVA. The mean sF2 values of patients who had locoregional failure were significantly higher than those who achieved local control (P sions. Testing intrinsic radiosensitivity using the surviving fraction at 2 Gy (sF2) is comparable using the two assay methods of ATP- CVA and clonogenic assay. The ATP- CVA should be further investigated in the testing of intrinsic radiosensitivity in patients with cervical cancer.

关键词：放射敏感性 ATP细胞克隆形成化疗敏感性生存曲线照射剂量局部控制临床结局独立预后因素放疗反应

Clinical and Demographic Profile of Women with Uterine Fibroids Living in Puerto Rico

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Open Journal of Obstetrics and Gynecology 2024年第9期14卷 1347-1362页

作者： Edwin Y. soto-Velázquez Alexander J. Jaramillo-Cañas shania N. Aponte-Paris Gabriela V. Martínez-Marrero Irazu s. Guinan Gabrielle A. Rivera-Maldonado Alexandra Novas Pedro L. Cruz-Rosa Idhaliz Flores-Caldera Maricarmen Colón-Diaz Department of Physiology and Pathology San Juan Bautista School of Medicine Caguas Puerto Rico United States Ponce Research Institute Ponce Health Sciences University Ponce Puerto Rico United States

Introduction: Uterine leiomyomas, or fibroids, are prevalent benign tumors affecting up to 70% of reproductive-age women in the United states, significantly impacting productivity and quality of life. Despite their commonality, the epidemiology and clinical patterns of leiomyomas in Puerto Rico remain inadequately researched. Methods: This study conducted a secondary data analysis using clinical, menstrual cycle characteristics, and demographic data from self-administered questionnaires of women undergoing diagnostic laparoscopy for endometriosis in Puerto Rico. Chi-square tests and t-tests analyzed categorical and continuous variables, respectively (p Results: Among 1,610 endometriosis cases, 312 included uterine fibroids. Prevalence estimates were 10.3% (40 years). Primiparous women averaged 22.14 years, with 40.71% having 2 - 3 pregnancies and 26.28% experiencing miscarriages. symptoms included infertility (29.5%), dyspareunia (40.7%), severe pain (50%), and dysmenorrhea (75.6%). Comorbidities included ovarian cysts (52.2%) and abnormal uterine bleeding (37.8%). Conclusions: Advanced age, parity, and comorbidities like diabetes and hypertension were prevalent in our cohort. Understanding the epidemiological profile of women living in Puerto Rico with uterine fibroids is crucial for improving diagnostic awareness and enhancing patient care.

关键词： Uterine Fibroids Puerto Rico Epidemiology Dysmenorrhea Abnormal Uterine Bleeding

Laser texturing of piston ring for tribological performance improvement

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Friction 2023年第10期11卷 1895-1905页

作者： Rita FERREIRA Óscar CARVALHO Luís sOBRAL sandra CARVALHO Filipe sILVA CMEMs-UMinho University of MinhoGuimarães 4800058Portugal LABBELs-Associate Laboratory Guimarães 4800058Portugal CEMMPRE-Center for Mechanical Engineering Materials and ProcessesUniversity of CoimbraRua Luís Reis SantosCoimbra 3030-788Portugal MAHLE Componentes de MotoresS.A.Núcleo Industrial de MurtedeCantanhede 3060-372Portugal

The radial surface coating layer of compression piston rings is used to improve their wear resistance during the internal combustion engine ***,at top dead centers,the friction coefficient of the piston ring–cylinder liner pair is detrimental to the engine’s tribological *** this work,dimples with different texture dimensions and densities were tested in a home-developed *** friction coefficient was measured for all samples,and for those with the best results,their wear resistance was *** texture with an aspect ratio of 0.25 and a density area of 15%reported the best tribological results.

关键词： piston ring surface texture friction wear

The cochlear implant and possibilities for narrowing the remaining gaps between prosthetic and normal hearing

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World Journal of Otorhinolaryngology-Head and Neck surgery 2017年第4期3卷 200-210页

作者： Blake s.Wilson Department of surgery Duke University School of Medicine Durham NC USA Department of Biomedical Engineering Duke University Durham NC USA Department of Electrical and Computer Engineering Duke University Durham NC USA Division of Head and Neck surgery and Communication sciences Department of Surgery Duke University Medical Center Durham NC 27710 USA

Background:The cochlear implant has become the standard of care for severe or worse losses in hearing and indeed has produced the first substantial restoration of a lost or absent human sense using a medical ***,the devices are not perfect and many efforts to narrow the remaining gaps between prosthetic and normal hearing are ***:To assess the present status of cochlear implants and to describe possibilities for improving ***:The present-day devices work well in quiet conditions for the great majority of ***,not all users have high levels of speech reception in quiet and nearly all users struggle with speech reception in typically noisy acoustic *** addition,perception of sounds more complex than speech,such as most music,is generally poor unless residual hearing at low frequencies can be stimulated acoustically in conjunction with the electrical stimuli provided by the *** for improving the present devices include increasing the spatial specificity of neural excitation by reducing masking effects or with new stimulus modes;prudent pruning of interfering or otherwise detrimental electrodes from the stimulation map;a further relaxation in the criteria for implant candidacy,based on recent evidence from persons with high levels of residual hearing and to allow many more people to benefit from cochlear implants;and 'top down' or 'brain centric' approaches to implant designs and ***:Progress in the development of the cochlear implant and related treatments has been remarkable but room remains for *** future looks bright as there are multiple promising possibilities for improvements and many talented teams are pursuing them.

关键词： Auditory prosthesis Cochlear implant Cochlear prosthesis Deafness Neural prosthesis