贫困山区县如何探索农机监理发展新路子

湖北竹溪县是一个典型的山区农业县,农业一直是县域经济发展的支柱.自1993年农用拖拉机受公安部门委托农机部门监管已来,农机监理事业得到快速发展,执法力度、执法水平逐步增强,全县拖拉机交通安全状况明显好转,农用拖拉机营运行业一度成为推动城乡经济发展的一支生力军.时至新旧世纪之交,营运拖拉机锐减、拖拉机列管面正呈逐步萎缩趋势,这种不良现象严重制约了农机监理事业的发展,而且在贫困山区县都带有一定的共性,笔者就这个问题谈一些肤浅的认识.

Octahedral Cu_2O-modified TiO_2 nanotube arrays for efficient photocatalytic reduction of CO_2

A photocatalyst composed of TiO 2 nanotube arrays（TNTs） and octahedral Cu2 O nanoparticles was fabricated,and its performance in the photocatalytic reduction of CO2 under visible and simulated solar irradiation was studied. The average nanotube diameter and length was 100 nm and 5 μm,respectively. The different amount of octahedral Cu2 O modified TNTs were obtained by varying electrochemical deposition time. TNTs modified with an optimized amount of Cu2 O nanoparticles exhibited high efficiency in the photocatalysis,and the predominant hydrocarbon product was methane. The methane yield increased with increasing Cu2 O content of the catalyst up to a certain deposition time,and decreased with further increase in Cu2 O deposition time. Insufficient deposition time（5 min） resulted in a small amount of Cu2 O nanoparticles on the TNTs,leading to the disadvantage of harvesting light. However,excess deposition time（45 min） gave rise to entire TNT surface being most covered with Cu2 O nanoparticles with large sizes,inconvenient for the transport of photo-generated carriers. The highest methane yield under simulated solar and visible light irradiation was observed for the catalysts prepared at a Cu2 O deposition time of 15 and 30 min respectively. The morphology,crystallization,photoresponse and electrochemical properties of the catalyst were characterized to understand the mechanism of its high photocatalytic activity. The TNT structure provided abundant active sites for the adsorption of reactants,and promoted the transport of photogenerated carriers that improved charge separation. Modifying the TNTs with octahedral Cu2 O nanoparticles promoted light absorption,and prevented the hydrocarbon product from oxidation. These factors provided the Cu2O-modified TNT photocatalyst with high efficiency in the reduction of CO2,without requiring co-catalysts or sacrificial agents.

Effect of Anodization Parameters on Morphologies of TiO2 Nanotube Arrays and Their Surface Properties

This work presents the potentiostatic anodization study of titania nanotube array films fabricated in fluoride-based organic electrolytes including DEG （diethylene glycol） and EG （ethylene glycol）. The work focuses on the effect of important anodization parameters such as applied voltage, anodization time, and electrolyte type on nanotube morphologies and corresponding surface properties. Depending upon unique nanotube formation structures obtained from each anodizing electrolyte, wettability of the nanotube array layer has been determined by means of the contact angle measurement. The EG nanotube array films with close-packing cell orientation are found to show hydrophilic behavior. While the well separated DEG nanotube array films are found to exhibit hydrophobic behavior, with the characteristics of more discrete, wider cell separation obtained through manipulating the electrolyte conditions and the fabrication techniques offering considerable prospects for developing the superhydrophobic sample surface. Such formation structures observed for the DEG fabricated nanotube is believed to play a prominent role in determining the surface wettability of the anodized nanotube array film. The achieved result in this work is anticipated to pave the way to other relevant applications, where interfacial properties are critically concerned.

Influence evaluation of titania nanotube surface morphology on the performance of bioelectrochemical systems

In order to investigate the effect of the surface morphology and resistance of the TiO2 semiconductor on current output,TiO2 nanotube array bio-anodes(TNA)are synthesized at different electrolyte temperatures,thereby changing the length and surface roughness of the nanotubes.When the anodizing temperature is increased from 30 to 75℃,the length of the nanotubes increases from 1.459 to 4.183μm,which hinders the transfer of extracellular electrons to the electrodes.On the other hand,the surface roughness of TNA is significantly improved at higher temperatures,which is conducive to electron transfer.Therefore,samples processed at 45℃have the best current output performance.Compared with the treatment at 30℃under anodization,samples processed at 45℃can balance the resistance and roughness and have a higher electron transfer rate;the current output density of which is increased by 1.5 times,and the decolorization rate is increased by 0.8 times.Therefore,proper TNA surface morphology can improve the current output and the potential of wastewater treatment.

Surface photovoltage phase spectroscopy study of the photo-induced charge carrier properties of TiO_(2) nanotube arrays

By using the surface photovoltage (SPV) technique based on a lock-in amplifier, surface states located 3.1 eV below the conduction band of TiO_(2) have been detected in TiO_(2) nanotube arrays prepared by anodization of titanium foil in fluoride-based ethylene glycol solution. The photo-induced charge transportation behavior of TiO_(2) nanotube arrays was also studied by quali- tatively analyzing their SPV phase spectra measured under different external bias. When a negative bias was applied, carriers excited from surface states have the same transportation properties as those excited from the valence band; in contrast, when a positive bias was applied, these two kinds of photo-excited carriers exhibit different transportation behavior..

Super-tough and strong nanocomposite fibers by flow-induced alignment of carbon nanotubes on grooved hydrogel surfaces

Nanocomposite fibers have attracted intensive attentions owing to their promising applications in various fields. However, the fabrication of nanocomposite fibers with super toughness and strong strength under mild conditions remains a great challenge. Here we present a facile flow-induced assembly strategy for the development of super-tough and strong nanocomposite fibers with highly ordered carbon nanotubes (CNTs), which can be induced by directional and fast flow on a grooved hydrogel surface. The prepared nanocomposite fibers show excellent mechanical properties, with a tensile strength up to 643±27 MPa and toughness as high as 77.3±3.4 MJ m^-3 at ultimate strain of 14.8±1.5%. This versatile and efficient flow-induced alignment strategy represents a promising direction for the development of high-performance nanocomposites for practical applications.