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Consumer electronics such as portable devices (laptops, smartphones) become smaller, thinner and more powerful. In such devices a passive cooling begins to play a dominant role in heat dissipation process. In passive cooling systems thermal resistance of thermal path between semiconductor junction and radiator should be progressively reduced. It can be done by application of efficient (high thermal...
The steady state method is a commonly used and in principle simple way to measure thermal resistance and conductivity of thermal interface materials (TIMs). The sample must be positioned between a hot and a cold plate with constant temperatures, whereby a heat flow through the sample and temperature gradient across the sample are generated. To determine the thermal resistance of the sample the heat...
For the energetic support of reflow soldering an exothermic reacting paste has been developed. This paste is applied on electronic assemblies adjacent to solder paste deposits before reflow soldering. During the reflow process a chemical reaction inside the paste is releasing energy in the form of heat. This heat is assisting in melting up the solder paste depots, hence allowing the processing of...
Thermal interface materials (TIMs) are an important enabler for low thermal resistance and reliable electronics packaging for a wide array of applications. There is a trend towards bonded interface materials (BIMs) because of their potential for low thermal resistance (<1 mm2-K/W). However, due to coefficient of thermal expansion mismatches between various layers of a package, thermomechanical...
This paper is about the design, fabrication and analysis of parabolic trough. Idea of research is to concentrate the solar energy at some focal point to generate enough temperature that can generate steam. That steam can be used to run a steam engine for production of electricity. In this research project a parabolic trough is designed and its efficiency is checked experimentally. Luminance and temperature...
Low-temperature sintering of nanosilver is emerging as a promising lead-free die-attach solution for packaging of semiconductor devices for high-power density or high-temperature applications. However, the bonding process requires either a relatively long heating cycle up to one hour under zero pressure or hot pressing at which the parts are under several MPa of uniaxial stress for tens of seconds...
We present a characterization study to develop self-polarized, highly pyroelectric lithium tantalate thin films obtained by RF magnetron sputtering. A preliminary work is done on the bottom electrode to reduce short-term variations of the pyroelectric behavior. Then, the influence of pressure and of deposition temperature is studied to determine the best set of parameters as to obtain a large pyroelectric...
The main scope of this paper is to investigate the adhesion effect on the mechanical response of MEMS components from RF switch application by using an atomic force microscope (AFM). The occurrence and strength of adhesion effects in MEMS devices depend on a variety of environmental, geometrical and operational parameters (temperature, relative humidity, contact area, surface energies of contact materials,...
CuBO2 is prepared by a solid-state reaction method to investigate thermoelectric properties in high temperature. The XRD result confirms the CuBO2 compound existing in this method. The Seebeck reveals the compound displays p-type thermoelectric material. The experimental results of electrical resistivity exhibited results of 0.004 S/cm to 0.038 S/cm with the temperature range of 650 to 830 K. The...
Hyperspectral longwave infrared (LWIR) is used for a variety of targets such as gases and solids with the advantage of day or night data collections. A longwave infrared system must have the ability to convert the radiance data it measures to emissivity prior to running a detection algorithm, commonly called a temperature-emissivity separation (TES) algorithm. Key parts of this TES algorithm are accounting...
A III-nitride-based Quantum Cascade detector grown by MOCVD is designed, fabricated and tested. Peak responsivity of 100 µA/W with detectivity of up to 108 Jones at ∼ 4 µm is measured.
By carefully designing a multi-quantum well infrared photodetector (QWIP) heterostructure, we present an asymmetric QWIP with a localized state in the continuum. A narrow photocurrent spectrum confirms the electron confinement above the barrier.
This paper presents a mechanism that involves the integration of a pixel blind to infrared (IR) radiation into a focal plane array (FPA) for thermal detection. The blind pixel serves as a reference capacitor while scanning the FPA active pixels. In harsh environment conditions (e.g. shocks and wide changes in ambient temperature), this mechanism yields down to a 0.83% percent error in the measured...
Human fatigue is related to several factors, the ways to alleviate it are different, too. Traditional medical relief method can only from the perspective of one or a few alleviate human fatigue, and the effect is often poor. First, this paper studies the non-medical way of alleviating human fatigue. Then, this paper analyzes the defects of the products to alleviate human fatigue. In the end, this...
The identity of a material may be obtained by measuring its emis-sivity spectrum. Unfortunately, hyperspectral remote sensing instruments measure spectral radiance, which is a nonlinear function of the material's emissivity and temperature, the atmospheric downwelling radiance, and other factors. Therefore, accurate interpretation of hy-perspectral data requires estimation and separation of these...
Thermal impedance spectroscopy (TIS) is a non-destructive method for characterizing thermal properties of entire battery cells. Heat capacity, thermal conductivity and heat exchange with environment are determined by an evaluation of the heat transfer behavior of the battery. TIS measurements are usually conducted with contact-based temperature sensors, such as thermocouples or thermistors, which...
Battery is a critical component of an electric vehicle and electric non-road mobile machinery. The performance of a battery system must be assessed by experimental testing to achieve high reliability. This paper describes the development and validation of a battery pack for a mining load-haul-dump loader application. The typical duty cycle is used as a validation power profile.
Since a laptop caught fire in 2006 at the latest, Li-ion cells were considered as more dangerous than other accumulators [1]. Recent incidents, such as the one involving a BYD e6 electric taxi [2] or the Boeing Dreamliner [3], give rise to questions concerning the safety of L#i-ion cells. This is a crucial point, since Li-ion cells are increasingly integrated in all kinds of (electric) vehicles. Therefore...
In the process of sludge treatment, it's a very important technological link of mixing the material, but the key is how to ensure the accuracy and reliability of the feed's weight. The changes in the sludge size, shape, humidity, viscosity, weight, etc. lead to the output signals of the ordinary weighing instrument unstable, so it's difficult to achieve ideal control effect through the traditional...
This paper discusses measurement of temperature on busbar connection based on contact resistance and plating material in relation to the value of contact resistance. This study is intended to prevent failure when busbar connection is attached. The failure of the electrical connection can occur due to bad contact so that the contact resistance is increased, high losses, overheating, and it can even...
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