Selective Area Growth and Characterization of GaN Nanorods Fabricated by Adjusting the Hydrogen Flow Rate and Growth Temperature with Metal Organic Chemical Vapor Deposition

CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.

Research and Analysis on Cooling Capacity of Temperature Adjustment Equipments in Agricultural Multi-span Greenhouse

The high summer indoor temperature in agricultural greenhouse is not conducive to crop growth,so it is necessary to cool the greenhouse. In this study,taking the agricultural multi-span greenhouse with strong temperature adjustment ability for example,we make an experimental analysis on the temperature changes inside and outside the greenhouse under nine different equipment combinations( fan,skylight,sunshade,sunshade + fan,cooling pad + fan,skylight + fan,sunshade + skylight,sunshade + fan + cooling pad,sunshade + skylight + fan),respectively,and conduct the overall assessment on the measures to cool the summer agricultural greenhouse,in order to provide a reference for selecting a cost-effective cooling method for greenhouse. Tests show that the three treatment modes of fan,sunshade and sunshade + fan almost have no cooling capacity; skylight,sunshade + skylight have cooling capacity,but the effect is slow; cooling pad + fan,sunshade + skylight +fan can reduce the indoor temperature,but the effect is not very good; skylight and fan have good cooling effect; sunshade + fan + cooling pad has obvious cooling effect,which can well meet the cooling needs in the summer greenhouse.

supported by the National Natural Science Foundation of China(Nos.62172051,61772085,and 61877005)and Jiangsu Agriculture Science and Technology Innovation Fund(No.CX(18)3054).

Numerous neural network(NN)applications are now being deployed to mobile devices.These applications usually have large amounts of calculation and data while requiring low inference latency,which poses challenges to the computing ability of mobile devices.Moreover,devices’life and performance depend on temperature.Hence,in many scenarios,such as industrial production and automotive systems,where the environmental temperatures are usually high,it is important to control devices’temperatures to maintain steady operations.In this paper,we propose a thermal-aware channel-wise heterogeneous NN inference algorithm.It contains two parts,the thermal-aware dynamic frequency(TADF)algorithm and the heterogeneous-processor single-layer workload distribution(HSWD)algorithm.Depending on a mobile device’s architecture characteristics and environmental temperature,TADF can adjust the appropriate running speed of the central processing unit and graphics processing unit,and then the workload of each layer in the NN model is distributed by HSWD in line with each processor’s running speed and the characteristics of the layers as well as heterogeneous processors.The experimental results,where representative NNs and mobile devices were used,show that the proposed method can considerably improve the speed of the on-device inference by 21%–43%over the traditional inference method.