仿生智慧型熱控制系統
通常使用隔熱材料可以降低熱量傳遞,而使用風扇、散熱片、熱導管等用來單向散熱。但如何在一個系統上同時滿足隔熱和雙向傳熱的需求呢?因此我研究設計了仿生智慧型熱控制系統,能隨環境改變而快速轉變成隔熱或轉變成雙向傳熱並控制熱傳遞的方向及大小,這可以應用在房屋、汽車、恆溫系統等。我先自製了自動傳熱量測系統,測試並找出好的隔熱和傳熱材料及構造。為了能快速控制熱的方向及大小,我又發展了第一代替換式、第二代熱柵式和第三代熱管式熱控制系統;經過多次實驗,利用低沸點有機溶劑和控制系統,我成功地完成仿生智慧型熱控制系統,讓熱隔絕或快速流進流出,比傳統的方法改進很多,也達到節約能源的目的。Insulation materials are usually used to reduce heat transfer rate, while fans, radiators and heat pipes are applied to increase heat transfer rate and bring heat away. But is it possible to have both functions of insulation and heat transfer together in a single system? This research is to design and develop an intelligent heat control system, with both function of insulation and function of transferring heat together. Besides, this system can control the direction and amount of heat transferred. Such a system can be applied in house walls, cars, thermostatic system, etc. I developed an automatic heat measurement system which was used to test the properties of heat transfer for different materials and structures. Three generations of intelligent bi-directional automatic heat control system were then developed to get fast heat transfer and function of heat control. They were phase 1 replacing-type system, phase 2 heat-grating system, and phase 3 heat-pipe system. After tens of experiments, I successfully control the amount and rate of heat transfer via low-boiling-point organic solutions and controller. The designed system is bi-directional, and is more innovative and efficient than conventional uni-directional heat control methods. Besides, this system also has huge contribution in reducing energy consumption.
Synthesis and Characterization of Niobium Nitride Nanowires
This project aims to explore the potential of inexpensive in-situ deposition of niobium nitride nanowires to improve electrical conductivity. Transition metal nitrides are well known for attributes such as superconductivity, high melting point, simple structure as well as excellent electrical and thermal conductivities. In particular, niobium nitride possesses exceptional hardness and high reflectivity, as well as being a stable field emitter, making it well suited to applications as a cold cathode material. Niobium nitrides are formed by the uptake of nitrogen by niobium. This is achieved by the exothermic formation of an interstitial solid solution of nitrogen atoms in the bcc lattice of the niobium. Existing research has established the possibility of preparing niobium nitride by heating niobium in nitrogen or ammonia over a range of temperatures, by heating niobium pentaoxide and carbon in the presence of nitrogen as well as by chemical vapor deposition of other niobium compounds, nitrogen or hydrogen. For the purpose of this study, a two-step process was used for synthesis. The benefits of a two-step process over direct ammonolysis are apparent, from the greater degree of freedom pertaining to parameter determination. Additionally, characterization of niobium pentaoxide nanowires synthesize under similar conditions is also made possible by terminating the reaction earlier. NbN nanowires were synthesized by annealing niobium pentaoxide nanowires at 850 oC for 2 hours. Subsequent characterization was done using Raman Spectroscopy, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The presence of NbN nanowires via the conversion of Nb2O5 was ascertained by the absence of sharp peaks at 1000 cm-1 for Raman Spectroscopy and XRD plots. Field emission (FE) properties and electrical properties of NbN nanowires were then measured. NbN nanowires were found to have a high turn-on voltage, stable and relatively good field emission characteristics, demonstrating its potential as a cold cathode material. No current saturation was observed for an applied electric field of 0 to 6.0 V/ μm (5). This suggests a low degree of contact resistance for nanowires produced by this method of annealing, since the passage of electrons is not obstructed. Hence there will only be a small voltage drop between the SiO2 substrate and NbN nanowires. Samples containing NbN nanowires were dislodged by ultrasound to form an aqueous suspension of nanowires. A drop of suspension was dripped onto gold-finger substrates, and current-voltage (I-V) measurements of resultant nanowire bridges were taken. NbN nanowire bridges display Ohmic properties, in comparison with Nb2O5 nanowires that are semiconducting. Nanowire bridges obtained by heat-drying were denser and had better electrical properties than those obtained by evaporation to dryness. NbN nanowire bridges display Ohmic properties, in comparison with Nb2O5 nanowires that are semiconducting. Further work would include varying the cooling processes to observe any changes or deformation. Additionally, niobium nitride nanowires can be hybridized with carbon nanotubes (CNTs). A more in-depth comparison between niobium oxide and niobium nitride nanowires is also proposed, along with exploration of the nitrification of other transition metals.
Universal computing sorting machine
The purpose of the study was to develop and create a semi-automatic multi-purpose sorting and counting machine of standard articles. Currently, there is a problem of equipping industrial enterprises as well as small trade companies and large retailers with computing sorting machines of standard products of a certain shape. We would like to fill this missing link up with a simple, compact and inexpensive device. Procedures The proposed research consisted of a consistent design of a virtual model of the device and its electronic-mechanical implementation. The virtual model is simulated by a computer program "SolidWorks" object, which graphically shows the operation of the future device. In the development of the computing sorting device standard electronic devices and their associated software have been used. The created simplified real model demonstrates the basic principles and characteristics of the proposed device. Data As an example for the implementation of the concept device a computing device for sorting coins, in circulation in Russia has been created. As a basic principle of sorting objects by their geometric and weight characteristics were used. It is important that the device is focused on the correct form of the objects of sorting (balls, rings, coins, regular polyhedrons, screws, nuts, etc). To confirm the effectiveness of the computing device of this type of sorting, a series of tests of counting of objects manually have been carried out . The effectiveness of the device is determined by comparing the time characteristics of manual and automatic sorting. Findings and conclusions As a result of research and work performed, we have concluded that: 1) The proposed device can be used in various industries. (for example, while sorting ball bearings.) 2) Such a computing sorting device may find it's application in various commercial enterprises: to assist cashiers in retail ATMs. 3) Can be used in payment terminals. 4) 4) After a certain modernization of the device it can be used for money encashment.
滑鼠狂想曲
光學滑鼠會以很高的速度不斷地對著接觸面拍照,藉由比對每幅影像間的變化來偵測滑鼠移動的速度與方向,本研究利用此特點而設計一個簡易的光學量測系統,其中包括透鏡、光源與接觸面材質的選擇,以及利用Raw Input 模式讀取個別滑鼠移動訊息而發展出來的量測程式,使得此系統可以在無接觸與無摩擦的情況下來測量外界物體的移動速度與距離,經由實驗證明,在光學感測器還可以感應與追蹤的範圍內,量測的數據還蠻精準的。接觸面到光學感測器透鏡的距離越遠,能夠測得移動物體的極速也越高,但是會造成感測器的解析度下降,如此限制了接觸面的材質種類,無法量測表面較為光滑的物體,但是在設計得宜的情況下,仍有蠻多方面的用途,日後若能採用較高效能的光學感測器並加上測距儀的輔助,相信此系統的應用層面會更為廣泛。Optical mouse can take continuous snapshots very quickly of the contact surface and compare the images sequentially to detect the direction and amount of movement. This study uses this feature to design a simple optical measurement system, including lens, illumination and contact surface choice, as well as the measurement program using raw input model to accept the movement information from the mouse. This system can measure the distance and speed of the motion object under the non-friction condition. From the experiment test result, this optical measurement system is workable and satisfactory. Contact surface to optical sensor distance farther, can measure the higher speed of the motion object, but will cause the lower resolution of the optical sensor. This will limit the variety of the contact surface; superficial smoother object is unable to measure. In the future if we can use the high performance optical sensor and assist with rangefinder, believed this system can have more widespread applications.
Construction of a Mechanical Prototype of a Microtremor Recorder
Ambient vibration, the movement of the ground caused by transient objects such as the relative to values obtained using the commercial recorder. The natural ambient vibration of a control site was simultaneously obtained using the mechanical prototype and the commercial recorder, which were situated next to each other during the actual recording. Moreover, both sensors were used to record a control stimulus for a constant amount of time. The data obtained from these subparts were processed using WinWaveShot which quantified and presented ambient vibration as waves. The deviations of the maximum and minimum amplitudes, mode and median values of these waves, as graphed by DADiSP2002, was performed to verify the accuracy or reliability of the prototype. These graphs were converted to their DFT graphs and histograms, with accompanying converted wave properties which characterized the predominant frequency. Based from the results, the recordings obtained from the mAVR are proportional from the ones obtained from the eAVR. Therefore, the mechanical prototype is capable of recording the predominant frequency of a site. The prototype, when improved, is a potential alternative to commercial sensors since it is able to record actual movements and its scale is proportional to the scale of the eAVR. Since the prototype was constructed and can be reproduced from readily available and inexpensive materials, ambient vibration analysis can be used more commonly by architects and engineers for construction purposes. To verify the reliability of the values obtained using the prototype, the ambient vibration of other sites must be recorded and compared to those using the eAVR. wind, sounds and human activities, is one major site effect evaluation method presently used. The respective predominant frequencies of a site and the structures above it obtained using this method serve as reference to the renovation and/or construction of structures. Predominant frequencies of the landmass and the structures above it should be non-identical to avoid prolonged shaking with the occurrence of an extensive movement of the ground as dictated by resonance effect. Since electronic ambient vibration or microtremor recorders, specifically their sensors, are expensive and inaccessible, a mechanical prototype of such device was designed and constructed. The proposed design of the mechanical ambient vibration recorder (mAVR) was mainly based on the IRIS Seismograph which makes use of the principle of electromagnetic induction. The relationship between ground motion and the movement of the prototype lever, which is a direct proportion, was the concept highlighted by the prototype’s mechanism. After the design of the mAVR prototype was finalized, its assembly, which consisted of the calibration of the solenoid and the inertial mass, was performed. The calibration of the solenoid was based on the voltage output of its solenoid based on the number of turns while the inertial mass was determined based on the equilibrium level of the prototype lever. Having proven the mAVR’s capacity to function by simulating stimulus, the testing of its accuracy was done with two setups: recording of (1) natural and (2) induced ambient vibration. This tested the prototype’s accuracy
Shock Induced Battery
a. Purpose of the Research Evidence has shown that people are becoming more aware of environmental protection than in the past. Not only has the government made every effort to implement the policies of environmental protection, but Hong Kong citizens are also more willing to cooperate and help out. However, when it comes to conservation of energy and reduction of wastage, many people still regard it as a burden and they just take it lightly. In fact, environmental protection can be achieved in a convenient and simple way. We can easily put in practice in our daily lives. Because of this, we would like to introduce our invention - “shock Induced battery” by using our knowledge of Physics. b. Procedures The “Shock Induced battery” makes use of locomotion of human bodies to generate electricity. The electrical current generated from the specially designed generator will pass through the diode bridges, which adjust the current to one direction. This enables the electrical energy to be stored in the capacitor. This energy will be released when the battery is correctly connected to a circuit with a switch and a resistor. One of the features of the battery is that it is portable. It is mainly used to charge up electrical devices. But it is hoped that it will replace non-chargeable cells one day, and can directly be used in any electrical devices. In fact, our ultimate goal is to reduce the wastage of materials for making the cells, and to solve the problem of disposal of these cells. c. Data The induced a.c. voltage is full-wave rectified by the diode bridge. d. Conclusions In a word, we are trying to provide a chance for people to put environmental protection in practice, so as to raise the awareness of people about environmental protection. After all, high-tech products only solve the power-saving problem to a certain extent, but it is the awareness and the initiatives of the public which matter. We are convinced that environmental protection brings fun to your daily lives, as you will find practices on environmental protection both convenient and simple.
Titania Nanotubes for Solar Energy and Catalysis
Introduction The discovery of titania (TiO2) nanotubes suggests vast improvements over extant titania properties. Titania nanotubes are aligned in highly-ordered arrays with a large geometric surface area, making them the ideal material for many applications. However, the mechanism responsible for the growth rates of highly-ordered nanotubes with optimal adhesive properties is not fully explained or understood. Purpose of Research The aims of this project were threefold: to explore the effects of different anodizing parameters on the fabrication of titania nanotubes; to study the photocatalytic activity of the nanotubes; and to deposit gold nanoparticles into the nanotubes. Methodology Nanotube Fabrication: Titanium foil was subjected to potentiostatic anodization with the use of various fluorinebased electrolytes, anodization voltage and duration to compare the effects of different parameters. Scanning electron microscopy (SEM) was used to characterize the nanotube diameter and length of the anodized samples. Photo-electrochemica1 Water-splitting: A PEC cell was assembled using the nanotubes as the photoanode and the samples were anodically polarized in a 1M KOH electrolyte. A potentiostat was employed to control the applied bias and to measure the photocurrent response under light irradiation. Overall photoconversion efficiency (ηc) of the samples was then calculated. Catalyst Support: A gold precursor solution was prepared with HAuC14‧3H2O. Using a novel depositionprecipitation (DP) protocol, gold nanoparticles were deposited on the nanotubes. SEM was used to scan for traces of gold and their locations. Energy-Dispersive X-ray (EDX) spectroscopy was used to confirm the identity of the gold nanoparticles. Data and Discussion Nanotube Fabrication: Preliminary studies found the glycerol/water and glycerol/formamide combinations to be the most promising. In glycerol/water-based electrolytes, higher water content corresponded to a decrease in nanotube length while higher anodization voltage resulted in a significant increase in tube diameter and length. In glycerol/formamide-based electrolytes, higher water content corresponded to a decrease in nanotube diameter while higher fluorine concentration resulted in an increase in inter-tubular spacing. The effects of various fabrication parameters were better understood, contributing to greater control over array dimensions. Photo-electrochemical Water-splitting: A higher anodizaion voltage resulted in a significant improvement in photoconversion efficiency. However, this trend was reversed in chlorine-doped samples, where a longer anodization duration corresponded with better photoconversion efficiency. Doping was found to enhance the photoresponse of the samples, with 6.32 % photoconversion efficiency obtained, suggesting new strategies for light harvesting and a step closer towards commercially-viable solar energy. Catalyst Support: Gold nanoparticles (5-10 nm) were successfully deposited onto the titania nanotube samples. Based on current literature, this was the first successful attempt at depositing gold nanoparticles into titania nanotubes. An EDX spectrum confirmed the identity of the gold nanoparticles. Compared to current catalytic converters, the gold/titania nanotube structure offered a larger catalytic surface area for reactants and the ability to function at low temperatures. Conclusion: By understanding the effects of various parameters on titania nanotube fabrication, the anodization process can be optimized to enable more precise control over array dimensions. High photocatalytic efficiency has also been achieved. In addition, doping is found to improve the photoresponse of titania nanotubes. Gold nanoparticles have been deposited, to our knowledge for the first time, onto the surface and inner walls of titania nanotubes.