8,772 research outputs found
Avaliação de sensor SAW de temperatura
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2009Este trabalho objetiva estudar sensores de temperatura sem fio baseados na tecnologia SAW (Surface Acoustic Wave - ondas acústicas superficiais). Os sensores SAW utilizados são baseados na sensibilidade dos parâmetros de propagação de ondas SAW em um substrato piezelétrico encapsulado em um circuito integrado. Estes sensores dispensam alimentação e podem ser interrogados à distância, sem fio. O conhecimento dos parâmetros do sensor é necessário para possibilitar o projeto de um interrogador para com ele formar um sistema de medição. Foi utilizado um único modelo de sensor, que opera na faixa de frequência de 433 MHz, com faixa de medição de (0 a 120) °C. Para a avaliação, foram utilizados equipamentos de radiofrequência ligados através de cabos e interface de conectores, exigindo o emprego de técnicas específicas para desacoplá-los, pois interferem significativamente no resultado das medições. Os critérios de avaliação do sensores se basearam nos diferentes indicadores de ressonadores e a comparação com sensores convencionais de temperatura. Chegou-se à conclusão de que a interface de comunicação entre equipamentos e dispositivo sob teste é muito relevante, alterando de forma significativa os resultados. Também concluiu-se que os sensores SAW tem resposta linear e comportamento estável com o tempo
Static stiffness of curcular saw blades
No full textThe article outlines the technique of strain estimating of a band saw blade. The quality of processing depends on the strain character of a band saw rim, improved quality of processing being provided by the saws where the rim is not displaced in opposite directions over the saw perimeter under axial loading
Effect of Credit Recovery Management Practices on Bank Performance at Yoma Bank ( Saw Yu Nandar, 2024)
No full textThe objectives of this study are to identify the credit recovery management practices at
Yoma Bank and to analyze the effect of credit recovery management practices on the bank's
performance. The credit recovery management practices considered loan monitoring, bank
specific metrics, debt recovery strategy and credit risk management. Quantitative research
method is used in this study. The study utilizes a combination of primary and secondary data
sources, with primary data gathered through questionnaire surveys. Descriptive statistics and
multiple regression analysis are employed to determine the results. In this study 100
employees was collected the survey, representing 71% of the total population through simple
random sampling method. Findings from the regression analysis indicate that loan monitoring
and credit risk management show a positive and significant impact on bank performance at
the 5% level. In contrast, bank-specific metrics and debt recovery strategies don't significantly
influence performance. Enhanced loan monitoring can greatly improve the performance of
Yoma Bank, where credit risk management also plays a crucial role. To achieve good bank
performance, Yoma Bank should enhance loan monitoring and credit risk management
practices. Developing robust loan monitoring systems will provide customers with feedback
and insights into their repayment processes, encouraging better performance. Additionally,
implementing tools to help customers visualize their loan status and potential savings from
timely repayments could be beneficial. Improving credit risk management practices by
offering educational resources about credit management can empower customers to make
informed financial decisions and further enhance bank performance
Saw-Toothed Microstructure-Based Flexible Pressure Sensor as the Signal Readout for Point-of-Care Immunoassay
No full textA saw-toothed
microstructure-based flexible pressure sensor was
designed as the signal readout for point-of-care (POC) immunoassay
of carcinoembryonic antigen (CEA). In this portable POC bioassay,
the sandwich-type immunoreaction was first carried out to capture
the target on a microplate, which simultaneously introduced the platinum
nanoparticles (PtNPs). Upon adding hydrogen peroxide (H2O2), the pressure as the bridge between the molecular
recognition event and detectable signal was increasing rapidly, resulting
from the decomposition of H2O2 accelerated by
PtNPs. Meanwhile, a flexible pressure sensor was fabricated with high
sensitivity; the ability of the pressure response was dramatically
improved by adopting the saw-toothed microstructure. By coupling with
the pressure sensor, the pressure change could be monitored in real
time to achieve the portable detection of CEA. Under the optimum conditions,
the proposed pressure-based bioassay presented good sensing performance
within 0.1–40 ng/mL at a detection limit of 87 pg/mL. The reproducibility,
precision, and accuracy provided by the method were also studied and
satisfied
Saw-Toothed Microstructure-Based Flexible Pressure Sensor as the Signal Readout for Point-of-Care Immunoassay
No full textA saw-toothed
microstructure-based flexible pressure sensor was
designed as the signal readout for point-of-care (POC) immunoassay
of carcinoembryonic antigen (CEA). In this portable POC bioassay,
the sandwich-type immunoreaction was first carried out to capture
the target on a microplate, which simultaneously introduced the platinum
nanoparticles (PtNPs). Upon adding hydrogen peroxide (H2O2), the pressure as the bridge between the molecular
recognition event and detectable signal was increasing rapidly, resulting
from the decomposition of H2O2 accelerated by
PtNPs. Meanwhile, a flexible pressure sensor was fabricated with high
sensitivity; the ability of the pressure response was dramatically
improved by adopting the saw-toothed microstructure. By coupling with
the pressure sensor, the pressure change could be monitored in real
time to achieve the portable detection of CEA. Under the optimum conditions,
the proposed pressure-based bioassay presented good sensing performance
within 0.1–40 ng/mL at a detection limit of 87 pg/mL. The reproducibility,
precision, and accuracy provided by the method were also studied and
satisfied
Imaging the SAW Field on Suspended 2D Membrane
No full textSurface acoustic wave (SAW) is widely used in biological research and sensor applications, acomprehensive understanding of SAW propagation and visualization on suspended 2D membranes is crucial for the manipulation of nanoparticles in biological research and sensitivity improvement of SAW sensors based on 2D material. The initial step of this project involved exciting a standing SAW field on the SAW device and attempting to use Digital Holography Microscopy (DHM) for imaging the standing SAW field on the substrate. This attempt was very challenging and unfortunately was not successful. We used an Atomic Force Microscope (AFM) as an alternative solution for SAW field imaging. Initially, AFM was used to image the SAW field on the SAW device substrate, and the impacts of input frequency and power on the amplitude of the SAW field were investigated. Subsequently, microcavities were fabricated on the SAW device to record images of the SAW field within the microcavities and their surrounding areas, aiming to investigate the impact of microcavities on the SAW field. Finally, the prepared graphene membrane was transferred to the microcavities, the SAW propagation was recorded on the suspended membrane and the influence of the suspended membrane on SAW propagation was analyzed.Mechanical Engineering | Precision and Microsystems Engineerin
PUBLIC PERCEPTION ON THE EFFECTS OF ENVIRONMENTAL NOISE POLLUTION ON PEOPLE’S HEALTH (A CASE STUDY IN KAMAYUT TOWNSHIP, YANGON) (Nang Saw Yu Nwe, 2019)
No full textarea, people tend to forget about it becauseit cannot be seen or smell likes other pollutions such as air, water, soil and light. The aim of this study is to evaluate the perception of public on environmental noise pollution and its effect on health and to Though environmental noise pollution is an increasing problem, especially in urban investigate the major source of noise in Kamayut Township. Descriptive method with quantitative approach was used for this study. The structured questionnaire was used to collect information from respondents. This study found that the major source of noise in Kamayut Township is noises from car with 48% of respondents, because it is one of the downtown urban areas with crowded transport network in Yangon. It also found that the psychological health of the respondents due to noise pollution is more affected than the physical health effect. In term of awareness, the results showed less awareness since 63% of the respondents think noise pollution cannot have a serious effect on health, 75% of the respondents have never discussed about noise pollution and 63% of the respondents do not know there are rules and regulations to control noise pollution. Respondents in this study know that the noise pollution can have effects on human health but do not think it will affect seriously
A thesis submitted as a partial fulfillment of the requirements for the degree of Master of Banking and Finance (MBF) (Saw Yu Nwe, 2018)
No full textThis study focused on relationship between leadership styles & organizational commitment to Myanmar Citizens Bank (MCB). The objectives of the study and learned the employee commitments (affective, continuance, and normative commitment) in MCB Bank. It is known that an individual that have a good in leadership skill can able to change the entire organizational system within the organization. The purpose of this research is to examine or evaluate the effectiveness of leadership style towards the organizational commitment in the banking industry area at MCB Bank. In this research, independent variables such as transactional, transformational, servant and participative leadership are being discussed to determine their correlation or significant relationship with organizational commitment.
There a total of 120 sets of questionnaire had been distributed to banking employees in MCB Bank and total number of 80 sets had been collected. Based from the findings, all independent variable have significant relationship (transformational, transactional, servant and participative) or correlation with dependent variable (organizational commitment).
Furthermore, if studies are to focus on the banking industry, they can emphasize on special banking employees such as top management position who have experience is leading in the banking industry. The most employees, their managers were found which transformational leadership style, transactional leadership style, and participative leadership style are least dominant, servant leadership style which is moderate dominant, This study examined the leadership styles and organizational commitment in MCB Bank which was found that the servant leadership style are most existing leadership style alternative comparing other leadership style. Therefore, the dominant leadership style of MCB bank is the servant leadership style ones
Application of Slanted Finger Interdigital Transducer SAW Devices to Ultraviolet Array Photodetectors
No full text表面聲波元件（SAW）為一種廣泛應用的元件，如運用在濾波器、共振器、震盪器、感測器等，對現代生活帶來許多的便利性，而SAW會被廣為運用的幾個主因為體積小且為被動元件與可利用微機電製程大量製造等的優點。而為了提升元件的效應，必須使用高係數的壓電材料或是複合材料，也耦合了更多其他的效應在其中，如光電效應、熱電耦效應等，因此研究這些效應對表面聲波元件的影響就相當的重要。
在本文中，我們利用氧化鋅的光電特性與表面聲波元件間產生聲電耦合效應，藉此來製作光感測器，由於鈮酸鋰的表面波波速與機電耦合係數較高，可製作出高靈敏度的紫外光感測器，光波長感測範圍介於 之間，且可量測至 等級的微弱光源，由於單一線寬的表面聲波元件無法製作陣列化的光感測器，因此在本文中，我們利用斜指叉電極的特性，將光感測器製作為陣列化的量測元件，探討陣列化的感測元件在各種參數的變化下對表面聲波元件的影響，並成功的利用陣列化光感測器進行光強量測，並探討陣列化感測器的特性與量測結果比較。In recent years, surface acoustic wave (SAW) devices are commonly used as filters, resonators, sensors, etc.. SAW devices offer many attractive advantages, for example, they are passive and small by MEMS fabrication. They are highly sensitive and output signal has the form of RF signal allowing the combination with the wireless sensor. Sometimes, we must use piezoelectric materials with high coupling coefficients or layered structures in order to have better performance. Other interactions arise in SAW devices, such as temperature, and acoustoelectric effect. In this paper, we analyze the influence of UV light effect on the frequency characteristics of SAW devices, and these devices are used as a photodetector.
In general, velocity and attenuation of SAW devices are affected by acoustoelectric interations and/or mass loading effect. In this research, the interactions of acoustoelectric effect with piezoelectric fields is investigated. The substrate used in the SAW device is lithium niobate (LiNbO3) crystal which has high acoustic velocity and large electromechanical coupling coefficient, so that the SAW device used as the photodetector is sensitive to the intensity of UV light. The wavelength of UV light is between and , and a intensity in the order of is easily detected from the SAW devices. The photodetector is designed as the array photo sensors in SFIT SAW devices. The array sensors are used to analyze the distribution of the UV light field and the characteristics of sensors are discussed.中文摘要I
英文摘要II
目錄III
表目錄VI
圖目錄VII
第一章緒論1
1.1研究動機1
1.2文獻回顧3
1.3本文內容6
第二章表面聲波元件的基本原理與理論模擬9
2.1壓電效應9
2.1.1壓電方程式10
2.2壓電基材的特性14
2.3表面聲波元件原理17
2.3.1表面聲波元件特性17
2.4脈衝函數模型理論 - Delta function model22
2.4.1單一頻率指叉電極換能器22
2.4.2寬頻指叉電極換能器25
第三章光電材料-氧化鋅36
3.1氧化鋅薄膜製作方式36
3.1.1射頻濺鍍法及其原理36
3.1.2鍍層成核與Thorton模型38
3.2氧化鋅薄膜特性40
3.2.1導電性質40
3.2.2光學性質41
3.3氧化鋅的分析與量測42
3.3.1氧化鋅薄膜表面與剖面狀態42
3.3.2X-ray 繞射分析43
3.3.3光學性質分析44
第四章實驗製成步驟與設備57
4.1實驗設計57
4.1.1壓電基板的選擇57
4.1.2斜指叉電極的設計58
4.1.3氧化鋅薄膜的幾何設計58
4.2微機電製程60
4.2.1晶圓清洗（clean）60
4.2.2金屬薄膜蒸鍍（Metallization）61
4.2.3微影製程（Lithography process）61
4.2.3.1塗佈光阻（PR coating）61
4.2.3.2曝光（Exposure62
4.2.3.3顯影（Development）62
4.2.4金屬蝕刻63
4.2.5氧化鋅薄膜沈積與蝕刻63
4.3量測系統架構64
4.3.1網路分析儀（Network Analyzer）64
4.3.2光源（Light Source）65
4.3.3單光儀（Monochromator）66
4.3.4光功率計（Power Meter）67
第五章實驗結果與討論82
5.1寬頻表面聲波元件特性量82
5.1.1操作頻率82
5.1.2指叉電極對數83
5.1.3指叉電極長度84
5.1.4延遲距離85
5.1.5頻寬86
5.2表面聲波元件之耦合效應與量測方87
5.2.1耦合效應87
5.2.2量測方法88
5.3氧化鋅光電效應對寬頻表面聲波元件影響之量測90
5.3.1氧化鋅薄膜厚度90
5.3.2氧化鋅感應區塊尺寸91
5.3.3操作頻率之影響92
5.3.4相對幾何位置92
5.3.5陣列排列93
5.4光感測器之分析與應用95
5.4.1光譜定量特性95
5.4.2重現性97
5.4.3光場分佈量測98
第六章結論與未來展望143
6.1結論143
6.2未來展望145
參考文獻14
Optimization of Saw Street Configuration to Save Saw Blade in Assembling QFN Packages
No full textSaw singulation is an indispensable process to sever the Mold Array Package (MAP) strips into individual units in assembling Quad Flat No-lead (QFN) packages. Mechanical saw, cutting the MAP strip along saw streets using dicing blade, is a mainstream mode in the saw singulation process. Accordingly, the dicing blade, a continuously consumed part, takes a significant portion of the assembly cost. The saw blade consumption is generally determined by saw blade type, MAP strip structure and process parameter. In this study, the effects of MAP strip structure, specifically, the saw street configuration in lead frame, on the saw blade saving have been experimentally investigated. The saw street configuration was first investigated by comparing the wear amount of saw blade for cutting discrete and continuous saw streets of equal length and same configuration in 3×3 mm, 6×6 mm and 9×9 mm QFN packages. It is found that (i) the wear amount of the discrete saw streets may be significantly less than its counterpart of the continuous saw streets and (ii) the saw blade saving in the discrete saw streets goes more as the package size goes smaller. The saw blade saving is attributed to the additional saw process improvement contributed by the discrete saw streets. The saw street configuration was also investigated by comparing the wear amount of saw blade for cutting saw streets of 5 mil and 8 mil lead frames in the 6×6 mm QFN package. It is proved that less metal amount in the saw street consumes less saw blade. The merit of the discrete saw street and metal amount reduction in saw street were then implemented in the revised lead frame of the 6×6 mm package, and the saw blade consumption per MAP strip dropped to 15.8 μm in revised lead frame from 113.0 μm in original lead frame in statistical sense.</jats:p
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