Nondestructive measurement of thermal contact resistance for the power vertical double-diffused metal-oxide-semiconductor

To obtain thermal contact resistance（TCR） between the vertical double-diffused metal-oxide-semiconductor（VDMOS） and the heat sink, we derived the relationship between the total thermal resistance and the contact force imposed on the VDMOS. The total thermal resistance from the chip to the heat sink is measured under different contact forces, and the TCR can be extracted nondestructively from the derived relationship. Finally, the experimental results are compared with the simulation results.

INVERSE COMPUTATION OF OPTICAL-ABSORPTION COEFFICIENT IN INHOMOGENEOUS MATERIAL WITH VARIED THERMAL CONDUCTIVITY

In this paper,for an inhomogeneous material in which the thermal conductivity varies as a function of depth,an efficient treatment is proposed to inversely calculate the depth distri- bution of optical- absorption coefficientby the surface temperature of the material.It is demon- strated that the results of inverse computation by that method are more similar to the experi- mental ones measured by some destructive method.Thus,the treatmentis more feasible to non- destructively estimate the distribution.

Research exploring greenhouse environment control over the last 50 years

Environments do not exist in isolation.Their main components in greenhouse systems are plants.Without consideration of plants,analysis of greenhouse environments and environmental control of greenhouses can be accomplished,although it is not simple to achieve.Initial attempts were undertaken to analyze greenhouse environments and then reproduce them.Ventilation rate effects on plant photosynthesis in a growth chamber were reported in 1966.Computer simulations then became a main subject of research.The first dynamic computer simulation of a greenhouse environment including plants was published in 1971.According to innovations of computer technology,the use of minicomputers and microcomputers spread in many areas.By measuring the net photosynthesis of lettuce plants grown under artificial lighting,air temperature was optimized using a minicomputer with the hill-climbing method.The method was designated as the Speaking Plant Approach to environment control(SPA).After the author developed the first reported environmental control system in Japan,systems using microcomputers spread widely for greenhouse environmental control.Knowledge-based expert systems were tested for plant management.Also,a machine vision system was developed to detect critical moments for watering of muskmelon plants.The first feed-forward control method for greenhouses with a large heat mass was reported.Then space farming was tested in 1996 to assess gravity effects on plants.Energy-saving aspects such as solar sterilization,ground heat storage system,and storage using phase change material(PCM)have been reported.Defects of ordinary solarimeters were reported in 2008 along with an approach to estimate evapotranspiration in a greenhouse without the effect of so-called cosine law.Later,this technique was expanded to estimate photosynthesis of the plant canopy in a greenhouse using newly developed sensor units.

Online ultrasonic terminal for measuring pig backfat thickness

The measurement of pig backfat thickness(PBFT)has to stand up to challenges with the reliability,accuracy,and convenience.Acquiring PBFT timely and precisely from a finite distance is extremely necessary to improve the process of pig production and implement effective management.In an attempt to alleviate these problems,an online handheld terminal was designed with a new method based on ultrasonic technology for measuring PBFT during the process of pig breeding,which can overcome the difficulties encountered in other destructive means.The terminal comprised three main components:a main microcontroller unit(MCU)to measure PBFT,a RFID module to identify each pig and send data(e.g.identity,measurement time and PBFT)to a server via wireless transmission module,and an ultrasonic transducer to drive and receive signals between them.A measurement error within 0-1 mm was acquired through testing three groups of samples.Results indicated that this handheld terminal had a required accuracy and proved that the ultrasonic wave processing method can be deployed in a mobile terminal for PBFT measurement.It also provided a feasible nondestructive alternative to measure PBFT.Associated with information management software platform,this method may ultimately help pig production farmers measure the PBFT accurately and conveniently,and improve the pig production efficiency.