Polyimide alignment layer is a very important liquid crystal alignment. The most well-known Liquid crystal display (LCD) alignment methods are homogeneous alignment and homeotropic alignment. This paper research uses different fluff depth and number of rubbing into polyimide,and changes the level of rubbing strength, to observe how electro-optical properties of vertical liquid crystal alignment changes with rubbing strength. By rubbing polyimide with different rubbing strength, this research uses two kind of negative liquid crystal (¡µ£`<0) as samples. This research finds that when rubbing strength increases, the contrast ratio tends to drop.However, the contrast ratio rises after certain level of rubbing strength is applied. Regarding the response time, this research finds that when rubbing strength increases, the response time tends to drop as well. However, the response time rises and falls irregularly after certain level of rubbing strength is applied.

The liquid crystal display on the liquid crystal alignment is known to be influenced by the rubbing strength. In the thesis, in order to figure out the best condition for homeotropic alignment, we add the number of rubbing, which causes the increase of the rubbing strength. In the experiment, we discuss two parts. The first part discusses the relation between polarity and liquid crystal. The instrument used mainly is contact angle measurement system, which measures the contact angle between liquid and sample and calculates the polarity, the dispersion and the surface free energy. In the second part, we change the rubbing strength to analyze the influence of liquid crystal cell. Also, we use the electro-optical measurement to analyze the cell which is fabricated by different rubbing strength. It is at this part that we focus on analyzing the optical texture, transmittance, contract ratio, and sharpness. The sample¡¦s polarity rises as the rubbing strength increases. It is the influence of the liquid crystal pretitle angles that the polarity as well as the liquid crystal cell¡¦s optical property changes. Such changes could be seen in transmittance, contract ratio and sharpness

Orientador: Milton Dias Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T18:51:00Z (GMT). No. of bitstreams: 1 Sousa_HairtondeJesus_M.pdf: 5983507 bytes, checksum: bbd9b5a7613f605ecdda388d19949395 (MD5) Previous issue date: 2010 / Resumo: Este trabalho consiste na aplicação das ferramentas de full spectrum na detecção de falhas em máquinas rotativas em cantraste com os half spectrum normalmente utilizados nas aplicações industriais. Nesta dissertação, o full spectrum é computado diretamente da manipulação das coordenadas complexas juntamente com o índice de forma e direcionalidade, que fornece uma informação clara sobre o movimento de precessão de qualquer seção do rotor. Inicialmente, utiliza-se um modelo de elementos finitos de um sistema rotativo a fim de se familiarizar com o seu comportamento dinâmico enquanto sujeito a forças de desbalanceamento Este modelo, que representa uma idealização do rotor usado na parte experimental deste trabalho, é constituído de dois mancais, um deles bastante macio e anisotrópico, e pode ser montado com duas configurações: com um e dois discos. Variando-se a velocidade de rotação e a distribuição espacial das forças de desbalanceamento foi possível identificar, ao longo do rotor, as seções que descreviam movimentos de precessão direta ou retrógrada. As mesmas análises realizadas no modelo numérico foram também conduzidas experimentalmente em uma bancada. Além disso, neste caso, foi também estudado o fenômeno do rubbing (roçamento), que ocorre quando o rotor toca (roça) o stator ou a parte interna dos mancais hidrodinâmicos. Neste experimentos a influência de dois parâmetros foram analizadas: a posição do estator ao longo do rotor - especialmente o movimento de precessão do ponto do eixo em contato com o estator - e a folga entre estator e rotor. Os dados adiquiridos foram analisados usando o full e o half spectrum e os mapas de ordem normal e direcional / Abstract: This work consists in the application of full spectrum tools in fault detection of rotating machinery in contrast to the half spectrum commonly used in industrial applications. In this dissertation, the full spectrum is computed directly from the manipulation of the complex coordinates together with the shape and directivity index, which provides clear information about the precessional motion of any part of the rotor. Initially, it is used a finite element model of a rotating system in order to get acquainted with its dynamic behavior while subjected to unbalance forces. This model, which represents an idealization of the rotor used in the experimental part the this work, has two bearings, one of them very soft and anisotropic, and can be assembled in two configurations: with one or two disks. Varying the rotational speed and the spatial distribution of the unbalance forces it was possible to identify, along the rotor, the stations describing forward or backward precessional motions. The same analyses performed on the numerical model were also experimentally conducted on an instrumented test rig. In this case, however, it was also studied the rubbing phenomenon, which occurs when the rotor hits (rubs) the stator or the internal part of the journal bearings. In these experiments the influence of two parameters were analyzed: the position of the stator along the rotor - especially the precessional motion of the shaft point in contact with the stator - and the stator gap. The acquired data were analyzed using the full and half spectrum and the full and half order map / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Rubbing alignment is widely used in display industry, Rubbing cause anisotropy in rubbed polyimide thin film influence the alignment of Liquid Crystal. The major part of this article is to analyze surface optical anisotropy of rubbed polyimide thin film. RAS signals and surface free energies of rubbed polyimide thin film with different rubbing strength are measured, and relationship between anisotropy of surface and rubbing strength is discussed. The mechanism of alignment can be understood by this work. Reflection Anisotropy Spectroscopy (RAS) has been used in Semiconductor as a tool to monitor crystal growth for many years. RAS is a non-contact and non-destructive measurement method. It only measures the difference of two orthogonal complex reflection signals and optical anisotropy of surface. It¡¦s very sensitive to the anisotropy of surface. In the current studies, RAS has been used to detect surface anisotropy of rubbed polymer. We measured the surface free energy of the rubbed polyimide thin films. It has been found that surface free energy is of anisotropy due to the application of mechanical rubbing to the polymer surface. Pretilt angle influences the alignment of liquid crystals. The molecule orientation of PI surface and anisotropy of rubbed PI surface effect pretilt angle¡CPretilt angles measured by pretilt angle measurement system compare with RAS signals. RAS signals, anisotropy of surface free energies, and pretilt angles are increasing with increasing rubbing strength.

In organic solar cell, the surface characteristic plays an important role in the power conversion efficiency of solar cell device. According to the literatures, the increased roughness can increase the contact area at the interface between PEDOT:PSS and active layer, improving hole extraction to the anode. Furthermore, a rough interface may cause a scattering effect on the incident light, which can reflect the out-lost-light back into the active layer and leads an efficient light absorbed. There are many ways to change the morphology of hole transporting layer, such as solvent-treated, or additives adding. However, the above process methods are easily affected by the external environmental conditions. It¡¦s difficult to get the surface morphology been well controlled, resulting in a process instability and low reproducibility. In this research, we will create regular grooves on hole transporting layer by rubbing method. By changing baking temperature and rubbing pressure adjustment of PEDOT:PSS layer; we can precisely control the groove depth and surface morphology. This method makes the process simple and high stability. We found that the PEDOT:PSS hole transporting layer with a suitable depth grooves can enhance the power conversion efficiency. The power conversion efficiency of samples were measured under AM 1.5G 100mW/cm2 illumination. In our results, we found that the device possess about 14.52nm-depth of groove structure, the power conversion efficiency of devices can be increased from 2.03% to 2.36% (which is 17.6% improved). This consequence can be attributed to a short current density increasing from 5.67mA/cm2 to 6.67mA/cm2 based on the device structure is ITO(1500Å)/Rubbing-PEDOT:PSS(500Å)/P3HT:PCBM(800Å)/Al(2000Å).

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24470号 / 理博第4969号 / 新制||理||1709(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 古市 剛史, 准教授 Huffman Michael Alan, 教授 今井 啓雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Orientador: Robson Pederiva / Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-09-11T21:11:47Z (GMT). No. of bitstreams: 1 Aquino_MarceloBrazde_D.pdf: 2578383 bytes, checksum: cfe62d4a785e2dd17a987600f5ef2e7c (MD5) Previous issue date: 2008 / Resumo: Este trabalho apresenta um procedimento de detecção do fenômeno de rubbing e seus efeitos em máquinas rotativas, aplicável para o regime estacionário e não-estacionário, utilizando como ferramenta de análise a Transformada de Wavelet. Primeiramente, aplica-se a Transformada de Wavelet Contínua (CWT) para sinais estacionários com o uso da wavelet Morlet Complexa como wavelet mãe, para extração de características intrínsecas da falha estudada. Aplica-se esta técnica para este regime de operação, pois, a análise multi-resolução é capaz de evidenciar possíveis transientes, mesmo no regime estacionário. Posteriormente, aplicou-se a Transformada de Wavelet Packet (WPT) visando-se analisar a variação da distribuição das energias contidas em bandas de freqüências específicas para o regime nãoestacionário. Diante da grande quantidade de informações contidas no sinal de partida e passagem pelas velocidades críticas do sistema, esta segunda técnica foi escolhida considerandose sua habilidade de compactação de dados, viabilizando o uso de outras técnicas e também o monitoramento on-line de máquinas. Todas as análises em questão, CWT no regime estacionário e a WPT no não-estacionário, são através de simulações computacionais com auxílio do Método dos Elementos Finitos e para sinais reais proveniente de uma bancada experimental de testes / Abstract: This work presents a detection procedure of the rubbing phenomenon and its effects in rotating machinery, applicable on the stationary and non-stationary regimes, using the Wavelet Transform as analysis tool. Firstly, the Continuous Wavelet Transform (CWT) is applied for stationary signals using the Complex Morlet wavelet as mother wavelet, for extracting of intrinsic features of the studied fault. The use of this technique and regime of operation is suitable, because, this multi-resolution analysis is able to evidence possible transients, even in the stationary regime. Afterward, the Wavelet Packet Transform (WPT) is applied for analyzing the variation of the energy distribution contained in bands of specific frequencies for the nonstationary regime. Related to the amount of information contained on the signal of run-up and while passing through the critical speeds of the system, this second technique was chosen by its ability of data compression that makes possible the use of another techniques as well as the online monitoring of machines. Both analyses, CWT in the stationary regime and WPT in the nonstationary one, are studied through computational simulations by the use of Finite Element Method and also through real signals got from the experimental test rig / Doutorado / Mecanica dos Sólidos e Projeto Mecanico / Doutor em Engenharia Mecânica

Internationally, the impacts of deer have been widely studied, but little work has been conducted in Australia. Sambar (Cervus unicolor Kerr) were introduced to Victoria in the 1860s from Sri Lanka, and have become established throughout eastern Victoria. This study is located in the Yarra Ranges National Park, 100 km north east of Melbourne. The park primarily consists of three protected water catchments that contribute approximately 50% to Melbourne’s water supply. This study was conducted from 2005 to 2008 in the Upper Yarra and O’Shannassy catchments. Large open areas covered by forbs and grasses periodically form adjacent to the water body of the Upper Yarra reservoir. Sambar are frequently observed at the largest of these areas known as The Flats. The impacts of sambar at this locality and in other areas of the catchments were investigated. / Faecal pellet transect surveys determined that sambar occupancy and density was greatest on open flats, lower on forest edges adjacent to open flats (< 250 m), and significantly less in other forested areas of the catchment. Observations of The Flats revealed that hinds were the main demographic class represented, with a mean group size of 39 individuals, and up to 70. This is the largest aggregation of sambar ever reported anywhere in the world, and equates to an approximate density of 200 km-2 at this site. / Selective exclosures effectively differentiated the offtake of forage by sambar from that of native herbivores. Sambar contributed to the majority of offtake at The Flats, and were able to obtain a substantial proportion of their daily food requirements from this source. A culling program began in the Yarra Ranges National Park in May 2008, to reduce the large numbers of deer in the park. The cull reduced the time spent by sambar on The Flats, as determined by faecal pellet accumulation plots, and significantly reduced faecal pellet load and forage offtake. / Sambar significantly decreased relative foliage cover of shiny nematolepis (Nematolepis wilsonii), a threatened understorey tree, through their antler rubbing activities. Thrashing of shiny nematolepis saplings also significantly decreased relative foliage cover, with sambar selecting saplings with a larger stem diameter from those available. Rubbed trees and thrashed saplings experienced damage to, on average, over half the stem circumference. / Selective exclosures allowed differentiation of sambar and native herbivore browsing on forest understoreys. Browsing by sambar in high densities prevented the vertical growth of plants in the understorey, with branches above 60 cm in height most commonly browsed. Plants in the understorey were more frequently and intensely browsed in areas of high sambar density. Three species were browsed to a significantly greater extent by sambar than native herbivores: hazel pomaderris (Pomaderris aspera), prickly tea-tree (Leptospermum continentale) and prickly bush-pea, (Pultenaea juniperina). Sambar significantly reduced plant biomass in forest understoreys where they occur in high densities. / The presence of large, open herb-rich areas drives the high local densities and associated impacts of sambar within the Yarra Ranges National Park. Future areas of research are identified and management recommendations are outlined. A sustained culling program appears to be the only practical option to reduce sambar density and impacts at this locality.

Reflectance anisotropy spectroscopy is a non-contact technique for surface detection. which means through the optical reflection from surface of the substrate measured. Because of its high sensitivity, RAS is used for in real-time control of semiconductor epitaxy. On our study, RAS is used to study the surface characteristics of liquid crystal alignment layer. We used rubbing for polyimide film to achieve alignment purposes. The rubbing strength is determined by adjusting the pile impress and the number of rubbed. We found that the anisotropy spectroscopy will appear after rubbing. And the strength of RA signals changes with photon energy of the probe beam. The pretile angle of the liquid crystal sandwiched in between rubbed PI show certain degree correlation with RA strength. In addition, using surface free energy measurement to explore the relationship with pretilt angle and try to connect three of them. We also tried to measure the reflection signal from the sample back. We found the signal of sample back would decay in UV region and it may be a result of UV absorption in the substrate.

Reflection anisotropy spectroscopy (RAS) is a non-destructive optical technique which can be used to measure the surface properties of sample. We use the technique to detect the optical anisotropy of rubbed polyimide thin film. Atomic force microscopy study of rubbed polyimide showed that rubbing produced microgrooves on the surface of the polyimide thin films, and the surface roughness of the polymer thin films increased slightly with the rubbing strength. Reflection anisotropy signals have been found to be generated on the surface of polyimide thin film on completion of mechanical rubbing, and will increase with an increase in the rubbing strength. We also tried to find out the correlation between RA strength of the polyimide alignment layer and pretilt angle of liquid crystal at the rubbed polyimide films.