ZnO films grown on cotton fibers surface at low temperature by a simple two-step process

Zinc oxide (ZnO) films have been synthesized and deposited onto cotton fiber surface using a simple two-step process. At first step, the cotton fiber surface was coated with a conductive layer of zinc-cellulose complex by rinsing the fibers in zinc chloride solution. After that, the growth of ZnO films was carried out in zinc acetate aqueous solution at room temperature, with alkaline aqueous solution drops continuously added under magnetic stirring. The morphology of the as-prepared ZnO-coated cotton fibers was characterized by scanning electron microscopy. Infrared and photoluminescence spectra were used to confirm the existence of ZnO. In addition, the formation mechanism of ZnO-coated cotton fibers is discussed in detail.     

Manifestation If Substance Molecular Structure in Temperature Effects of Light Scattering

DCMSL （depolarization components of molecular scattering of light） have been studied within the wide spectral range （0-200 cm-1） and in the temperature intervals （20-200 ℃） in toluol （C6HsCH3） and aniline （C6HsNH2）. It has been shown that when a liquid is heated and temperatures approach to critical ones, a significant contribution of DCMSL is made by vibration motion of molecules. The special properties of the temperature-frequency behavior of DCMSL spectra are discussed from the view point of hindered rotation of liquid molecules with consideration of intermolecular interaction.     

多层焊接金属波纹管刚度实验与数值计算对比分析

以机械密封用S型焊接金属波纹管为研究对象,首先通过建立S型波纹管的非对称截面有限元模型,对单双层波纹管在其弹性范围内分别进行了轴向刚度、扭转刚度的数值分析和EJMA标准法计算;其次,通过设计专用夹具测出了单双层波纹管的轴向及扭转刚度值,并将计算结果与试验值进行了对比和分析,从而得到了S型单双层波纹管轴向及扭转刚度的合理的计算方法,为波纹管的结构分析和稳定性提供了理论依据。     

The role of zinc vacancies in bipolar resistance switching of Ag/ZnO/Pt memory structures

We have presented a study of the bipolar resistance switching characteristics in the Ag/ZnO/Pt cell. This switching is accompanied by a change in intensity of the photoluminescence emission at 3.33?eV which is attributed to zinc vacancy related transitions in ZnO film. Besides voltage-driven resistance switching phenomena, a transition from a high-resistance state to a lower one is observed under laser illumination at low temperature. These results demonstrate that the bipolar resistance switching can originate due to an electron trapping/de-trapping process at zinc-vacancy defects localized in the interface layer. The Mott metal-insulator transition is proposed as a possible mechanism of the memory effect.     

Photovoltaic device on a single ZnO nanowire p-n homojunction

A photovoltaic device was successfully grown solely based on the single ZnO p-n homojunction nanowire. The ZnO nanowire p-n diode consists of an as-grown n-type segment and an in situ arsenic-doped p-type segment. This p-n homojunction acts as a good photovoltaic cell, producing a photocurrent almost 45 times larger than the dark current under reverse-biased conditions. Our results demonstrate that the present ZnO p-n homojunction nanowire can be used as a self-powered ultraviolet photodetector as well as a photovoltaic cell, which can also be used as an ultralow electrical power source for nanoscale electronic, optoelectronic and medical devices.     

Experimental performance of soil monitoring system using IoT technique for automatic drip irrigation

This paper proposes an IoT-enabled soil monitoring system using wireless sensor network for automatic irrigation in agricultural applications, especially for lemongrass plants, where an automated control system is required for irrigation applications. This can solve the problem of the water crisis, which is faced by the farmers during the cultivation of the crop in the field. This controls the water supply in the irrigation process using an IoT communication system. A system architecture for soil monitoring and controlling irrigation using IoT technique is designed where the different sensors and actuators like humidity, soil moisture, temperature, pump, and so forth are connected with a node microcontrol unit and message queuing telemetry transport (MQTT) protocol for enhancing communication capabilities. This wireless sensor network gives feedback to the system. This provides automation by the on/off pump system during drip irrigation. The sensor data are displayed on a PC or mobile phone through wireless communication and an IoT cloud platform. An experimental testing setup is developed and the experimental performance of a soil monitoring system using IoT technique for automatic drip irrigation has been carried out and soil moisture data are also stored in a cloud server for analytics. The performance shows that the MQTT protocol sends data within 48 s to the IoT cloud so that the data can be acquired in a faster manner. This shows that this kind of soil monitoring system is suitable for automatic drip irrigation, which enhances the farming process and overcomes the water crises in the agricultural system by reducing the wastage of water.