Growth and development ofThiobacillus ferrooxidans for engineering applications

A bioprocessing approach for the extraction of base, nuclear and precious metals from refractory and lean grade ores has been reviewed in this paper. Characteristic morphological features ofThiobacillus ferrooxidans, the organism which has been extensively used for biooxidation of sulphide ores have been discussed. Mechanisms of chemoautotrophy and mineral oxidation have been illustrated. The current engineering applications of this microorganism have also been brought out. Various methods for accelerating the growth ofThiobacillus ferrooxidans for faster biooxidation and genetic manipulation for development of desired strains have been outlined.     

Flexible Transparent Hierarchical Nanomesh for Rose Petal‐Like Droplet Manipulation and Lossless Transfer

Precise manipulation of water is a key step in numerous natural and synthetic processes. Here, a new flexible and transparent hierarchical structure is determined that allows ultra‐dexterous manipulation and lossless transfer of water droplets. A 3D nanomesh is fabricated in one step by scalable electrospinning of low‐cost polystyrene solutions. Optimal structures are composed of a mesh of dense nanofiber layers vertically separated by isolated mesoporous microbeads. This results in a highly adhesive superhydrophobic wetting that perfectly mimics rose petal‐like structures. Structural–functional correlations are obtained over all key process parameters enabling robust tailoring of the wetting properties from hydrophilic to lotus‐like Cassie‐Baxter and rose‐like Cassie‐impregnating states. A mechanistic model of the droplet adhesion and release dynamics is obtained alongside the first demonstration of a mechanically induced transfer of microdroplets between two superhydrophobic coatings. This low‐temperature reaction‐free material structure demonstrates a facile means to fabricate impenetrable residue‐less rose petal‐like surfaces with superhydrophobic contact angles of 152 ± 2° and effective adhesion strength of 113 ± 20 μN. This is a significant step toward parallel, multistep droplet manipulation with applications ranging from flexible on‐paper devices to microfluidics and portable/wearable biosensors.     

控制因素指导下的肌理操作--以莱州云峰山文化旅游产业区规划设计为例

肌理是城市空间形态的重要表征,本文以莱州云峰山文化旅游产业区规划设计为例,从肌理操作的角度,阐述提炼原有肌理的空间模式,结合控制因素的用地规划,剖析原有肌理重塑等思考成果,深入探索了肌理操作的模式和可行性。     

Improving controllable adhesion on both rough and smooth surfaces with a hybrid electrostatic/gecko-like adhesive

This paper describes a novel, controllable adhesive that combines the benefits of electrostatic adhesives with gecko-like directional dry adhesives. When working in combination, the two technologies create a positive feedback cycle whose adhesion, depending on the surface type, is often greater than the sum of its parts. The directional dry adhesive brings the electrostatic adhesive closer to the surface, increasing its effect. Similarly, the electrostatic adhesion helps engage more of the directional dry adhesive fibrillar structures, particularly on rough surfaces. This paper presents the new hybrid adhesive''s manufacturing process and compares its performance to three other adhesive technologies manufactured using a similar process: reinforced PDMS, electrostatic and directional dry adhesion. Tests were performed on a set of ceramic tiles with varying roughness to quantify its effect on shear adhesive force. The relative effectiveness of the hybrid adhesive increases as the surface roughness is increased. Experimental data are also presented for different substrate materials to demonstrate the enhanced performance achieved with the hybrid adhesive. Results show that the hybrid adhesive provides up to 5.1× greater adhesion than the electrostatic adhesive or directional dry adhesive technologies alone.     

Superhydrophobic “Pump”: Continuous and Spontaneous Antigravity Water Delivery

Antigravity transportation of water, which is often observed in nature, is becoming a vital demand for advanced devices and new technology. Many studies have been devoted to the motion of a single droplet on a horizontal or inclined substrate under specific assistance. However, the self‐propelled water motion, especially continuous antigravity water delivery, still remains a considerable challenge. Here, a novel self‐ascending phenomenon driven only by the surface energy release of water droplets is found, and a superhydrophobic mesh to pump water up to a height of centimeter scale is designed. An integrated antigravity transportation system is also demonstrated to continuously and spontaneously pump water droplets without additional driving forces. The present novel finding and integrated devices should serve as a source of inspiration for the design of advanced materials and for the development of new technology with exciting applications in microfluidics, microdetectors, and intelligent systems.     

Force‐Driven Single‐Atom Manipulation on a Low‐Reactive Si Surface for Tip Sharpening

A single atomic manipulation on the delta‐doped B:Si(111)‐()R30° surface using a low temperature dynamic atomic force microscopy based on the Kolibri sensor is investigated. Through a controlled vertical displacement of the probe, a single Si adatom in order to open a vacancy is removed. It is shown that this process is completely reversible, by accurately placing a Si atom back into the vacancy site. In addition, density functional theory simulations are carried out to understand the underlying mechanism of the atomic manipulation in detail. This process also rearranges the atoms at the tip apex, which can be effectively sharpened in this way. Such sharper tips allow for a deeper look into the Si adatom vacancy site. Namely, high‐resolution images of the vacancy showing subsurface Si dangling bond triplets, which surround the substitutional B dopant atom in the first bilayer, are achieved.     

基于光诱导介电泳的微粒自动化操作实验研究

采用等离子体增强化学气相沉积方法(PECVD)制备了氢化非晶硅(a-Si∶H)光电导薄膜,并利用双面胶技术封装ODEP芯片。构建了包括光投影模块和视频监控模块的ODEP自动化操作实验平台。以聚苯乙烯微粒为操作对象,进行微米尺度粒子的ODEP自动化操作实验,并深入研究了交流电压、投射光颜色和光电极形状对微粒运动速度的影响。实验结果表明,在交流电压频率和投射光颜色相同的条件下,粒子的运动速度与交流电压的幅值成线性关系,施加的交流电压幅值越大,微粒的运动速度越大。在交流电压的幅值和频率相同的条件下,投射光为白色时,粒子的运动速度最大;投射光为蓝色时,粒子的运动速度最小。当投射光为白光,电压为20V,频率为20kHz时,10μm和20μm聚苯乙烯微粒的最大运动速度分别为143μm/s和158μm/s。     

玻色-爱因斯坦凝聚的量子操控

玻色-爱因斯坦凝聚（BEC）是当前原子分子物理的一个国际前沿课题。自从1995年在激光冷却的基础上实现玻色-爱因斯坦凝聚（BEC）以后,全世界已有几十个研究小组成功地获得了BEC,并取得了一批引人注目的成果。研究玻色凝聚体的动量操控是超冷量子气体研究的重要研究方向,北京大学研究小组于2004年在实验上获得铷原子玻色凝聚以来,在玻色凝聚体的超辐射散射方面作了一系列研究工作,本文主要介绍该研究组近五年来利用超辐射散射在铷原子玻色凝聚动量操控方面的研究工作。