Hydrogen Functionalization of Graphene using RF Plasma for photodetection
The growth of the internet is propelling an ever-increasing need for faster communication. Modern telecommunication data is mainly carried through fibre-optic cables, with pulses of light representing bits of data; the main factor limiting data transfer speed is the rate at which the optical receiver at the opposite end of the cable can detect light pulses. Graphene-silicon Schottky photodiodes are a promising alternative to traditionally-used germanium photodiodes, promising higher detection frequency and better contrast between light and dark. To make it less susceptible to erroneous measurements due to graphene having a low band gap, hydrogen functionalisation was used to increase the barrier potential of the Schottky diode so that a higher voltage would be required to allow current to pass through in forward voltage bias and trigger the sensor. This study seeks to determine the optimal conditions — of physical proximity, duration of exposure, and plasma power — for hydrogen functionalisation using radio frequency plasma. Graphene was synthesised using low pressure chemical vapour deposition, then transferred onto P-type silicon to create a photodiode. The graphene-silicon photodiode was then doped with hydrogen plasma to introduce defects in the graphene layer to increase the barrier potential of the photodiode. To assess the effectiveness of hydrogen functionalisation, photocurrent measurements were conducted while light was shone onto the photodiode in pulses of increasing frequency to find the magnitude and spontaneity of the response. Light was shone in pulses of 100ms, and was successfully detected by the photodiode. The pulse spacings were gradually decreased and it was found that the diode was able to detect pulse spacings as low as 1µs, significantly better than germanium photodetectors. The sample demonstrated clear optoelectronic response and was sensitive to changes in frequency. Results show that the intensity of the optoelectronic response in graphene-silicon diodes is inversely related to its physical proximity to the plasma source during hydrogen functionalization; and directly related to the power of the plasma and to the duration of exposure up to a point, after which it will deteriorate. Thus, it can be concluded that graphene-silicon Schottky diodes offer much promise in electronic communication.
Mentor Hunt App
The Information Technology (IT) area has shown great growth in recent years, even with the economic recession that 巴西 has been through and the impact of the coronavirus pandemic. It is estimated that by 2024 the area will have a deficit of more than 290 thousand professionals. However, companies still face other difficulties in hiring, especially people who are looking for their first job in the Information Technology area. Most part of these difficulties are lack of qualified manpower and high prerequisites to fill internship or junior positions. As a result, the objective of this project is: to develop a platform that connects people who seek guidance, improvement or professional relocation in the Information Technology area with professionals that already have the experience they are seeking. The first step was a research and analysis of similar platforms in the market, whose proposal involves mentoring or professional connections, and it concluded that there are no services that fully meet the project’s proposal. In the second step, a research was done about mobile development, highlighting Flutter and Firebase platform. The third step defined the application’s features, such as suggestion of users and mentors, search for users, become a mentor, private chat, video calls, Portuguese and English languages, light and dark themes and profile customization. The suggestion of users and mentors is done by a match with the registered users, relating their areas of work (where the user has experience) and the areas of interest of each one. For the coding of the project, Flutter and Firebase technologies were used. To design the app, it followed Material Design specifications. For testing and distribution, the app was published on Play Store, Google’s Android application platform. The tests were performed by both the researcher and a selected group of users to verify if the functionalities were in accordance to what was defined in the beginning of the project. Perceiving the correct functioning of the application, the project achieved the proposed objective. In addition, it expanded its reach area, because it is possible to find users and mentors from any other area of the market.
THE BLIND'S SHINE
Nowadays, all blind people are able to read any type of text thanks to The Braille system, which is a system of reading by touch. The Braille system provides a good and important help to blind people but it’s not enough. They try to integrate into society, try to read and write the same as those blessed with sight. However, only 18% of people can actually write in Braille and doing so takes a lot of effort. While Braille techniques have existed for many years now, there isn’t one that takes advantage of the comfort and easiness of modern technology. To be fair and give more chances to the blind people, and with all the available technologies nowadays, we must find solutions and innovative ideas to fulfill this objective. And this is how our project was born. To be honest, it’s not just a project, for us it’s a dream. Our focus in this project is creating an automatic machine based on transforming our language to their language and transforming this new invention to assist the blind in writing whole texts through speaking. It will be easier than the traditional way. This part of the project will help us print Braille on paper automatically in the cheapest, fastest and easiest way, unlike the traditional method that not only takes a lot of time but also needs a professional. Our printer will only cost approximately 250$ compared to regular printers that cost 6500$! the principles of the code of the speech recognition are voice pickup in all languages as first step, second speech recognition, then speech translation, after that speech analysis and finally translation into Braille and printing it. As for the future, we will work on face, object and image recognition as a scanner to make the visually impaired people read the name of the object and recognize people’s faces like anyone else.
多邊形的剖分圖形數量之探討
從參考資料[1]可知，將凸n+2邊形利用n-1條不相交的對角線剖分成n個三角形的圖形數量即為卡特蘭數Cn。而我利用不相交的對角線把n+2邊形剖分成數個多邊形和三角形的組合，並從此類的剖分圖形與三角剖分圖形之關聯，進而由卡特蘭數的一般式推導出此類剖分圖形數量的一般式。在本研究中可得，若到把n+2邊形剖分成一個k+2邊形和多個三角形的圖形數量是(2n-k+1 n+1) ；把n+2邊形剖分成一個k+2邊形、一個m+2邊形和多個三角形的圖形數量，當m≠k，數量為n+2/2(2n-k-m+2 n+2) ，當m=k時，數量為n+2/2(2n-2k+2 n+2) ；把n+2邊形剖分成一個k1+2邊形、一個k2+2邊形、一個k3+2邊形、和n-k1-k2-k3 個三角形的剖分圖形，當k1,k2,k3兩兩相異時，數量為(n+2)(n+3)(2n-k1-k2-k3+3 n+3) ；把n+2邊形剖分成一個K1+2邊形、一個K2+2邊形、一個K3+2邊形、一個K4+2邊形和n-K1-k2-k3-k4個三角形的剖分圖形當k1,k2,k3,k4兩兩相異，數量為(n+2)(n+3)(n+4)(2n-k1-k2-k3-k4+4 n=4)。並猜測若k1,k2,...,ki兩兩相異時，把n+2邊形剖分成一個k1+2邊形、一個k2+2邊形、…、一個ki+2邊形、和n-Σkj 個三角形的剖分圖形數量為(n+i)!/(n+1)!(2n-Σkj+i n+i) 。