Fabrication and function examination of PZT-based MEMS accelerometers

In this study, a hybrid sol-gel method was used to fabricate Pb(Zr_0.52Ti_0.48)_0.98Nb_0.02O₃ (PNZT) piezoelectric thick films. By preparing Pb(Zr_0.52Ti_0.48)_0.98Nb_0·02O₃ sol-gel solutions and mixing them with PZT-5A piezoelectric powders, therefore, the thickness of single layer coating can be increased and reduce the risk of film cracks. The proposed PNZT films have the dielectric constant of 1750, dielectric loss of 0.063, remnant polarization of 58 μC/cm², and d₃₃ of 133 p.m./V. Piezoelectric cantilever beam MEMS accelerometers were then designed, simulated and fabricated via photolithography methods on Si substrates. The sensitivity and natural frequency of the cantilever beam accelerometer are 16.8 mV/g and 200Hz, respectively. Finally, a cantilever beam accelerometer is successfully applied for the server hard-drive fault detection.     

Build Strategy Investigation of Ti-6Al-4V Produced Via a Hybrid Manufacturing Process

Hybrid manufacturing (HM), which integrates additive and subtractive manufacturing in one system, has become a popular choice for near-net-shape fabrication of complex parts. Although HM systems have been investigated for decades with major efforts on hardware and motion control system development, less work has been done in the exploration of relationships between microstructure evolution and the HM processing parameters. Here, Ti-6Al-4V thin-wall structures are fabricated according to a design of experiments matrix that includes four main HM processing parameters: layer height, powder feed rate, input energy density, and preheat condition. Optical microscopy is used to characterize the microstructure and relate it to the final part mechanical properties using Vickers hardness test and tensile test. Finite element analysis is applied to predict transient temperature history in the HM process and to help understand the microstructure type formation.     

A novel printhead multiplexer data registration chip system with injection cavity design

Microsystem Technologies - The integration of logic function is enabling TIJ-based products to move ever further up-market. The depicted integrated circuit TIJ transducer array serves 1024 jets and...     

阿公店水庫越域引水路工程泥岩隧道之設計

阿公店水庫位於高雄縣燕巢鄉境,係以防洪為主並兼具灌溉及公共給水之多目標水庫,惟因庫區淤積情況嚴重,為恢復水庫原有功能並達水資源永續利用之目的,經核定辦理"阿公店水庫更新工程計畫",採台灣首創排潤蓄清之空庫防淤操作,輔以越域引水路導引旗山溪潔淨水源蓄存運用,以同時解決水庫防洪、淤積及給水問题於一舉。隧道基於水理及施工性考量採4.0m内徑2R-3R-3R之正馬蹄型斷面,隧道開挖主要可能遭遇問題包括擠壓破壞及砂岩夾層蕴藏地下水狀況,由於泥岩隧道岩體分類及支撐設計不盡適用CSIR-RMR及NGI-Q值之經驗設計法則,遂採近似Terzaghi之岩壓估算方式,輔以數值分析法計算隧道變形與岩體-支撐之應力,俾檢核支撐設計之適用性,施工期間並彙整監測资料進行反算分析回饑設計,以期達兼顧安全與經濟之合理設計。考量儘早有效抑制隧道岩體擠壓及潛變變形,確保隧道長期之穩定性,並可維護洞内施工動綜提升施工效率,隧道仰拱設計以預鑄混凝土版進行斷面支撐閉合。     

Application of two-stage fuzzy set theory to river quality evaluation in Taiwan

An indicator model for evaluating trends in river quality using a two-stage fuzzy set theory to condense efficiently monitoring data is proposed. This candidate data reduction method uses fuzzy set theory in two analysis stages and constructs two different kinds of membership degree functions to produce an aggregate indicator of water quality. First, membership functions of the standard River pollution index (RPI) indicators, DO, BOD(5), SS, and NH(3)-N are constructed as piecewise linear distributions on the interval [0,1], with the critical variables normalized in four degrees of membership (0, 0.33, 0.67 and 1). The extension of the convergence of the fuzzy c-means (FCM) methodology is then used to construct a second membership set from the same normalized variables as used in the RPI estimations. Weighted sums of the similarity degrees derived from the extensions of FCM are used to construct an alternate overall index, the River quality index (RQI). The RQI provides for more logical analysis of disparate surveillance data than the RPI, resulting in a more systematic, less ambiguous approach to data integration and interpretation. In addition, this proposed alternative provides a more sensitive indication of changes in quality than the RPI. Finally, a case study of the Keeling River is presented to illustrate the application and advantages of the RQI.     

A DNA methylation assay for detection of ovarian cancer cells using a HpaII/MspI digestion-based PCR assay in an integrated microfluidic system

Early and accurate diagnosis of cancer plays a very important role in favorable clinical outcomes. DNA methylation of tumor suppressor genes has been recognized as a diagnostic biomarker for early carcinogenesis. The presence of 5-methylcytosine in the CpG islands in the promoter region of a tumor suppressor gene is an important indicator of DNA methylation. However, the standard detection assay utilizing a bisulfite treatment and HpaII/MspI endonuclease digestion is a tedious and lengthy process and requires a relatively large amount of DNA for testing. In this study, the methylated DNAs of various tumor suppressor genes, HAAO, HOXA9 and SFRP5, were chosen as candidates for detection of ovarian cancer cells. The entire experimental process for the DNA methylation assay, including target DNA isolation, HpaII/MspI endonuclease digestion, and nucleic acid amplification has been realized in an integrated microfluidic system. The limit of detection using this developed system has been experimentally determined to be 10² cells/reaction. The entire process from sample loading to analysis of the results only took 3 h which is much faster than the existing protocols. Different sources of biosamples, such as cells, ascites and serums, could be detected with the methylated DNA, indicating that this developed microfluidic system could be adapted for clinical use. Thus, this developed microsystem may be a promising platform for the rapid and early diagnosis of cancers.     

Mapping knowledge to rules for scheduling expert systems

Although the theoretical framework of expert systems has been well established, the process of developing a non-trivial expert system is still considered a difficult task. The main reason for this is that the nature of expert systems is knowledge-intensive. Also, it is usually difficult for domain experts to explain or communicate their expertise to the system professionals. Many methodologies have been proposed to overcome this domain knowledge representation problem. Most of them require the assistance of an expert system shell (tool). However, with a purpose of helping the system development in mind, most of them were not satisfactory. This research takes the experience of implementing a course scheduling expert system, and suggests two analysis methods to describe the characteristics of course scheduling knowledge. It is shown that these methods provide assistance on clarifying the complicated scheduling problem. Another favorable advantage of this method is its capability helping the transferring of domain knowledge to rules in the knowledge base.     

Fiber mat deformation in liquid composite molding. II: Modeling

Mathematical models are proposed to simulate the flow induced fiber mat deformation during liquid composite molding. The fiber bed is treated as an elastic beam and the load acting on the bed causes its deformation. The lubrication approximation is used to simplify the resin flow equation in the fiber free region, while Darcy's law is used to calculate the pressure and velocity fields in the deformed fiber bed. The governing equations are solved using the control volume/finite element method. The numerical results show reasonable agreement with the experimental results from Part I.     

Analysis of resin injection molding in molds with preplaced fiber mats. I: Permeability and compressibility measurements

This work presents the characterization of fibrous reinforcement mats in resin injection molding. The fiber mat characterization involved determining the mat permeability and compressibility. Mold filling experiments were conducted using two or more different fiber types in the mat stack, which created transverse porosity, permeability, and compressibility variations. The effect of these variations was studied by taking flow pressure measurements and observing the progress of the flow front of a non-reactive fluid filling a clear acrylic mold that contained the reinforcement mat stack.