نتایج جستجو برای: thermal variations

تعداد نتایج: 399619  

Journal: :PloS one 2015
Xiaoli Yu Zheng Sun Rui Huang Yu Zhang Yuqi Huang

Thermal effects such as conduction, convection and viscous dissipation are important to lubrication performance, and they vary with the friction conditions. These variations have caused some inconsistencies in the conclusions of different researchers regarding the relative contributions of these thermal effects. To reveal the relationship between the contributions of the thermal effects and the...

Journal: :Journal of geophysical research 2009
C Lee W G Lawson M I Richardson N G Heavens A Kleinböhl D Banfield D J McCleese R Zurek D Kass J T Schofield C B Leovy F W Taylor A D Toigo

The first systematic observations of the middle atmosphere of Mars (35km-80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the dataset of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that ...

2004
ELIZABETH S. DETTMER

Abstmct-Measurements of thermal conductivity on conventional and newly developed electronic ceramics are presented as part of an effort to incorporate the new high thermal conductivity ceramics into microcircuit manufacturing. Motivated by large variations in values claimed by different vendors for ostensibly similar materials, a longitudinal bar apparatus was built to measure thermal conductiv...

2006
C. S. Lee Y. J. Chen W. C. Hsu K. H. Su J. C. Huang D. H. Huang C. L. Wu

High-temperature threshold characteristics of a symmetrically graded -doped InAlAs/ InxGa1−xAs/GaAs x=0.5→0.65→0.5 metamorphic high electron mobility transistor MHEMT have been investigated. The thermal threshold coefficients, defined as Vth / T, are superiorly low at 0.9 mV/K from 300 to 420 K and at −0.75 mV/K from 420 to 500 K. An interesting polarity change of the thermal threshold coeffici...

1990
John Geist Donald B. Novotny

A new type of thermal resolution test target optimized to minimize the effects of lateral thermal gradients at low thermal contrast is described. This target consists of thin-film inconel heater strips over an etched silica substrate bonded to an aluminum heat sink. A simple, finite-difference model is used to study how variations in target construction and materials affect the generated therma...

2002
Y. Q. Gu X. L. Ruan L. Han D. Z. Zhu X. Y. Sun

2 Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People’s Republic of China. 3 To whom correspondence should be addressed. E-mail: [email protected] With the development of new emerging technologies, many objects in scientific research and engineering are of sub-micrometer and nanometer size, such as microelectronics, micro-electro-mechanical systems (MEMS), bio...

2010
Uwe Boettcher Christopher A. Lacey Raymond A. de Callafon Frank E. Talke

Introduction In recent years, thermal actuated flying height control has been implemented in Hard Disk Drives (HDD) to reduce the effect of flying height variations due to manufacturing tolerances or write current introduced pole tip protrusion (Fig. 1). A stable low flying height is necessary to achieve low bit error rates (BER) [1]. Thermal flying height control is used in a “static manner” i...

Journal: :علوم و فنون کشت های گلخانه ای 0
داود مؤمنی d. momeni agricultural engineering research institute (aeri), karaj, iran.موسسه تحقیقات فنی و مهندسی کشاورزی، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج احمد بناکار a. banakar dept. biosyst. eng. tarbiat modares univ., tehran, iran.گروه مهندسی مکانیک بیوسیستم، دانشکده کشاورزی، دانشگاه تربیت مدرس، تهران برات قبادیان b. ghobadian dept. biosyst. eng. tarbiat modares univ., tehran, iran.گروه مهندسی مکانیک بیوسیستم، دانشکده کشاورزی، دانشگاه تربیت مدرس، تهران سعید مینایی s. minaei dept. biosyst. eng. tarbiat modares univ., tehran, iran.گروه مهندسی مکانیک بیوسیستم، دانشکده کشاورزی، دانشگاه تربیت مدرس، تهران

energy consumption is very high in greenhouses mainly due to off-season production. the main source of its energy supply is fossil fuels. due to the disadvantages of fossil fuels consumption and preventive laws in the incoming years, study on reducing consumption and replacing a part of them with renewable energy is essential. in this research, a solar heating system, equipped with a concentrat...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1382

‏‎the main purpose of this research was to:1.develop a coking model for thermal cracking of naphtha.2.study coke inhibition methods using different coke inhibitors.developing a coking model in naphtha cracking reactors requires a suitable model of the thermal cracking reactor based on a reliable kinetic model.to obtain reliable results all these models shall be solved simultaneously.for this pu...

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