检索结果-南通市图书馆

Turned Trochoidal Disturbance on a Liquid Jet Surface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第4期27卷 846-852页

作者： SADIK Shalom KIRZHNER felix KRAMARENKO Denis Department of Mechanical Engineering ORT Braude College Division of Environmental Water and Agricultural Engineering Faculty of Civil and Environmental EngineeringTechnion-IIT Haifa 32000 Israel Biotechnology Engineering ORT Braude College

This paper shows that a turned trochoidal function disturbance may lead to peripheral drops production. The resulting model is used to describe that a turned trochoidal disturbance leads to peripheral drops production on the liquid jet surface without the necessity for superimposed disturbances. The trochoid is a non-unique parametric function. Only non-unique parametric functions disturbances may lead to peripheral drops production. The trochoidal function disturbance is decomposed to Fourier series. Every Fourier element receives an amplification factor in accordance to the Rayleigh inviscid jet model. Peripheral drops are received on the jet surface. The paper shows that all trochoidal disturbance functions, prolate cycloid, cycloid and curtate cycloid have a capability of peripheral drops producing. A limited capability of peripheral drops production is introduced for the trochoidal curtate cycloid. Produced drops size are reduced for increasing the jet velocity and wave number. Smaller drops are also received by transition from the prolate cycloid to curtate cycloid disturbance.

关键词： drops liquid jet trochoidal function

Real-time calculation of fragment velocity for cylindrical warheads

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2019年第3期15卷 264-271页

作者： David felix Ian Colwill Elias Stipidis Institution of Engineering and Technology Stevenage England Member of British Computer Society London Institute of Electrical and Electronics Engineers London

To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickly, before the weapon hits the target. Fast predictions also need to be made in real time simulations when the impact of many different computer models need to be assessed. The research presented in this paper focuses on creating a fast and accurate estimate of one of these variables - the initial fragment velocity. The Gurney equation was the first equation to calculate initial fragment velocity. This equation, sometimes with modifications, is still used today where finite element analysis or complex mathematical approaches are considered too computationally expensive. This paper enhances and improves Breech’s two-dimensional Gurney equation using available empirical data and the principals of conservation of momentum and energy. The results are computationally quick, providing improved accuracy for estimating initial fragment velocity. This will allow the developed model to be available for real-time simulation and fast computation, with improved accuracy when compared to existing approaches.

关键词： Initial fragment velocity Real-time simulation Cylindrical explosion

Modelling geographic accessibility to Primary Health Care Facilities:combining open data and geospatial analysis

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2019年第3期22卷 174-184页

作者： Olanrewaju Lawal felix E.Anyiam Department of Geography and Environmental Management Faculty of Social SciencesUniversity of Port HarcourtPort HarcourtNigeria Centre for Health and Development University of Port HarcourtPort HarcourtNigeria

Ensuring healthy lives and promoting well-being for all ages is the 3rd Sustainable Development Goal(SDG).Inequality in access to health care remains one of the primary challenges in achieving the *** the ever-increasing expansion of urban areas and population growth,there is a need to regularly examine the pattern of accessibility of basic amenities across regions,States and urban *** study examined geographic access to Primary Health Care Facilities(PHCF)in Nigeria using the combination of open data and geospatial analysis ***,showcasing an approach can be replicated across different regions in Sub-Saharan Africa due to issues of information *** on elevation,location of health care facilities,population and network data were *** result shows that PHCF aggregate at certain locations,*** urban agglomerations,and transit route leading to these *** concentrations are found in the capital *** average travel time to the nearest PHCF is about 14 min(Standard Deviation±13.30 min)while the maximum is about 2 *** of low accessibility areas exist across the Akwa Ibom State in the Niger Delta region of *** is an indication that most places have good geographic *** the 1787 settlements identified in our dataset,98.3%are with good access(60 min).Geographic access is not the main limiting factor to health care access in the ***,computation of access to health care should take into consideration other dimensions of accessibility,to create a robust measure which will support effective and efficient health care planning and delivery.

关键词： Spatial accessibility geographic accessibility Sustainable Development Goal(SDG) Primary Health Care Facilities(PHCF) Niger Delta geocomputation

LHAASO: A PeVatrons explorer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2021年第10期64卷 125-126页

作者： felix A.Aharonian Dublin Institute for Advanced Studies Dublin 999015Ireland Max-Planck-Institute for Nuclear Physics Heidelberg 69029Germany

Over the last two decades,we have seen two revolutions in y-ray astronomy-at GeV and TeV *** detection of thousands of GeV and hundreds of TeV y-ray emitters representing more than ten galactic and extragalactic source populations indicates that cosmic ray(CR)factories are distributed throughout the Universe in a wide diversity of forms and scales(see,e.g.,ref.[1]and references therein).These days,we are witnessing a new revolution,this time in the PeV ***,the LHAASO Collaboration[2]reported detection of a dozen ultra-high-energy(UHE;E≥0.1 PeV)y-ray sources,thus opening a new window in the electromagnetic *** y-rays,produced in interactions of charged particles(protons and electrons)with an order of magnitude higher energies,serve as direct messengers of CR PeV atrons.

关键词： spectrum. representing galactic

The Hidden Side of the Story between the Placenta and Preeclampsia: Preliminary Results of a Prospective Cohort of Pregnant Women in Cameroon

在线全文

学校读者我要写书评

暂无评论

Open Journal of Obstetrics and Gynecology 2024年第4期14卷 610-620页

作者： Junie Annick Metogo Ntsama Ambroise Merci Engounou Seme Urielle Julie Tchuente Sutchueng Wilfried Loic Tatsipie Christian Vagoda Henry-Leonard Chatelin Mol Madye Ngo Dingom felix Essiben Cyrille Claude Noa Ndoua Yann chris Eng Odile Fernande Zeh Faculty of Medicine and Biomedical Sciences University of Yaound&#233 I Yaound&#233 Cameroon Faculty of Medicine and Pharmaceutical Sciences University of Dschang Dschang Cameroon

Introduction: Pre-eclampsia is a complication of pregnancy that generally occurs in the third trimester. It is associated with a maternal and foetal mortality rate of around 27%. In view of the grim picture painted by this condition for both mother and newborn, studies have been carried out into the early detection of patients at risk of developing pre-eclampsia. These make it possible to introduce pregnancy-specific monitoring and preventive strategies to reduce the incidence of the condition. Objective: To establish the link between placental ultrasound characteristics and the onset of pre-eclampsia. Methodology: A multicentre prospective cohort study was conducted in two hospitals in Yaoundé, namely the Yaoundé Gynaecological Obstetrics and Paediatrics Hospital and the Nkolndongo Health and Social Animation Centre, in the gynaecology and radiology departments over a period of 11 months, from October 2022 to August 2023. It included pregnant women who had undergone obstetric ultrasound between 12 and 18 weeks’ gestation. In addition to routine obstetric ultrasound, we performed obstetric Doppler measurements in these patients. The resistance index of the left and right uterine arteries, the umbilical artery and the placental volume were the characteristics sought. At the end of this examination, two groups were formed: cases (pathological Doppler group) and controls (normal Doppler group). Blood pressure and urine dipstick were taken at each antenatal visit until delivery, then during the immediate postpartum period and finally at 7 days, 21 days and 42 days after delivery. Results: Sixty-seven (67) patients were included. Of these, 35 (47.8%) had pathological Dopplers. Sixteen patients had arterial hypertension associated with proteinuria and were therefore labelled as pre-eclampsia (PE). This gives a prevalence of 23.9%. Fifteen (42.8%) of these patients belonged to the exposed group and one to the unexposed group. The mean IR of the pre-eclampsia patients was s

关键词： Pre-Eclampsia Doppler Ultrasound Placenta

Effect of pin profile and process parameters on microstructure and mechanical properties of friction stir welded Al-Cu joints

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2016年第4期26卷 984-993页

作者： M.felix XAVIER MUTHU V.JAYABALAN Department of Mechanical Engineering St Xavier’s Catholic College of EngineeringChunkankadai 629 003Tamil NaduIndia Department of Manufacturing Engineering College of Engineering GuindyAnna UniversityChennai 600 025Tamil NaduIndia

In friction stir welding(FSW), pin profile has more influence on material flow especially in welding of dissimilar materials with different yield strengths. In the dissimilar welding of aluminium and copper, the material flow behaviour is complex to understand and thus a study is needed to reveal the mechanism of flow behaviour and the resultant mechanical properties. Three pin profiles, whorl pin profile(WPP), plain taper pin profile(PTP) and taper treaded pin profile(TTP) were chosen. The effects of pin profile on the microstructure, microhardness and tensile properties were studied. Optical microscope, scanning electron microscope, X-ray diffraction and EDS analysis were used to characterize the microstructural features. Among the three pin profiles, PTP profile results in defect-free stir zone and maximum joint properties of yield strength of 101 MPa, tensile strength of 116 MPa and joint efficiency of 68% compared with the other pin profiles. However, the microhardness plots are more or less identical for all the pin profiles but follows fluctuating trend. This is attributed to the heterogeneous distribution of hard Cu particle. The superior joint properties are mainly attributed to the defect-free stir zone formation and dispersion strengthening.

关键词： aluminium copper friction stir welding pin profile microstructure mechanical properties

Long noncoding RNAs in prostate cancer： overview and clinical implications

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2016年第4期18卷 568-574页

作者： Bhavna Malik felix Y Feng Department of Radiation Oncology University of Michigan Ann Arbor Michigan USA Department of Radiation Oncology Urology and Medicine University of California at San Francisco USA Helen Diller Family Comprehensive Cancer Center University of California at San Francisco USA

Prostate cancer is the second most common cause of cancer mortality among men in the United States. While many prostate cancers are indolent, an important subset of patients experiences disease recurrence after conventional therapy and progresses to castration-resistant prostate cancer （CRPC）, which is currently incurable. Thus, there is a critical need to identify biomarkers that will distinguish indolent from aggressive disease, as well as novel therapeutic targets for the prevention or treatment of CRPC. In recent years, long noncoding RNAs （IncRNAs） have emerged as an important class of biological molecules. LncRNAs are polyadenylated RNA species that share many similarities with protein-coding genes despite the fact that they are noncoding （not translated into proteins）. They are usually transcribed by RNA polymerase II and exhibit the same epigenetic signatures as protein-coding genes. LncRNAs have also been implicated in the development and progression of variety of cancers, including prostate cancer. While a large number of IncRNAs exhibit tissue- and cancer-specific expression, their utility as diagnostic and prognostic biomarkers is just starting to be explored. In this review, we highlight recent findings on the functional role and molecular mechanisms of IncRNAs in the progression of prostate cancer and evaluate their use as potential biomarkers and therapeutic targets.

关键词： biomarker long noncoding RNAs (IncRNAs) prostate cancer

On Some Cycles in Wenger Graphs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2020年第2期36卷 492-502页

作者： Ye WANG felix LAZEBNIK Andrew THOMASON College of Mathematical Sciences Harbin Engineering UniversityHarbin 150001China Department of Mathematical Sciences University of DelawareNewark.DE 19716U.S.A. DPMMS Centre for Mathematical SciencesWilberforce RoadCambridgeUK

Let p be a prime,q be a power of p,and let Fq be the field of q *** any positive integer n,the Wenger graph Wn(q)is defined as follows:it is a bipartite graph with the vertex partitions being two copies of the(n+1)-dimensional vector space Fq^n+1,and two vertices p=(p(1),…,p(n+1))and l=[l(1),…,l(n+1)]being adjacent if p(i)+l(i)=p(1)l(1)i-1,for all i=2,3,…,n+*** 2008,Shao,He and Shan showed that for n≥2,Wn(q)contains a cycle of length 2 k where 4≤k≤2 p and k≠*** this paper we extend their results by showing that(i)for n≥2 and p≥3,Wn(q)contains cycles of length 2k,where 4≤k≤4 p+1 and k≠5;(ii)for q≥5,0

关键词： cycle pancyclic finite field Wenger graph graph embeddings

Ion emission from warm dense matter produced by irradiation with a soft x-ray free-electron laser

在线全文

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第1期9卷 71-84页

作者： Josef Krása Tomás Burian Vera Hájková Jaromír Chalupský Šimon Jelínek Katerina Frantálová Michal Krupka Zuzana Kuglerová Sushil Kumar Singh Vojtech Vozda Ludek Vysín MichalŠmíd Pablo Perez-Martin Marion Kühlman Juan Pintor Jakub Cikhardt Matthias Dreimann Dennis Eckermann felix Rosenthal Sam M.Vinko Alessandro Forte Thomas Gawne Thomas Campbell Shenyuan Ren YuanFeng Shi Trevor Hutchinson Oliver Humphries Thomas Preston Mikako Makita Motoaki Nakatsutsumi Xiayun Pan Alexander Köhler Marion Harmand Sven Toleikis Katerina Falk Libor Juha Department of Radiation and Chemical Physics Institute of PhysicsCzech Academy of SciencesNa Slovance 218221 Prague 8Czech Republic Laser Plasma Department Institute of Plasma PhysicsCzech Academy of SciencesZa Slovankou 318200 Prague 8Czech Republic Department of Surface and Plasma Science Faculty of Mathematics and PhysicsCharles University in PragueV Holesovi ckách 218000 Prague 8Czech Republic Department of Physical Electronics Faculty of Nuclear Science and Engineering PhysicsCzech Technical University in PragueV Holesovi ckách 218000 Prague 8Czech Republic Helmholtz-Zentrum Dresden-Rossendorf Bautzner Landstraße 40001328 DresdenGermany DESY Photon Science Notkestraße 85D-22607 HamburgGermany Institut de Minéralogie de Physique des Matériaux et de CosmochimieUMR 7590–UPMC/CNRS/IRD/MNHNSorbonne Université4 place Jussieu75005 ParisFrance Department of Physics Faculty of Electrical EngineeringCzech Technical University in PragueTechnická216627 Prague 6Czech Republic Center for Soft Nanoscience University of MünsterBusso-Peus-Straße 10D-48149 MünsterGermany Department of Physics Clarendon LaboratoryUniversity of OxfordParks RoadOxford OX13PUUnited Kingdom Central Laser Facility STFC Rutherford Appleton LaboratoryDidcot OX110QXUnited Kingdom Lawrence Livermore National Laboratory 7000 East AvenueLivermoreCalifornia 94550USA European XFEL GmbH Holzkoppel 4D-22869 SchenefeldGermany Technische Universität Dresden 01062 DresdenGermany

We report on an experiment performed at the FLASH2 free-electron laser(FEL)aimed at producing warm dense matter via soft x-ray isochoric *** the experiment,we focus on study of the ions emitted during the soft x-ray ablation process using time-of-flight electron multipliers and a shifted Maxwell–Boltzmann velocity distribution *** find that most emitted ions are thermal,but that some impurities chemisorbed on the target surface,such as protons,are accelerated by the electrostatic field created in the plasma by escaped *** morphology of the complex crater structure indicates the presence of several ion groups with varying *** find that the ion sound velocity is controlled by the ion temperature and show how the ion yield depends on the FEL radiation attenuation length in different materials.

关键词： electrostatic emitted chemi