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Precision micro components are increasingly in demand for various engineering industries, such as biomedical engineering, MEMS, electro-optics, aerospace and communications. The proposed requirements of these components are not only in high accuracy, but also in good surface performance, such as drag reduction, wear resistance and noise reduction, which has become one of the main bottlenecks in the development of these industries. However, processing these difficult-to-machine materials efficiently and economically is always a challenging task, which stimulates the development and subsequent application of vibration assisted machining (VAM) over the past few decades. Vibration assisted machining employs additional external energy sources to generate high frequency vibration in the conventional machining process, changing the machining (cutting) mechanism, thus reducing cutting force and cutting heat and improving machining quality. The current awareness on VAM technology is incomplete and effective implementation of the VAM process depends on a wide range of technical issues, including vibration device design and setup, process parameters optimization and performance evaluation. In this research, a 2D non-resonant vibration assisted system is developed and evaluated. Cutting mechanism and relevant applications, such as functional surface generation and microfluidic chips manufacturing is studies through both experimental and finite element analysis (FEA) method. A new two-dimensional piezoelectric actuator driven vibration stage is proposed and prototyped. A double parallel four-bar linkage structure with double layer flexible hinges is designed to guide the motion and reduce the displacement coupling effect between the two directions. The compliance modelling and dynamic analysis are carried out based on the matrix method and lagrangian principle, and the results are verified by finite element analysis. A closed loop control system is developed and proposed based on LabVIEW program consisting of data acquisition (DAQ) devices and capacitive sensors. Machining experiments have been carried out to evaluate the performance of the vibration stage and the results show a good agreement with the tool tip trajectory simulation results, which demonstrates the feasibility and effectiveness of the vibration stage for vibration assisted micro milling. The textured surface generation mechanism is investigated through both modelling and experimental methods. A surface generation model based on homogenous matrices transformation is proposed by considering micro cutter geometry and kinematics of vibration assisted milling. On this basis, series of simulations are performed to provide insights into the effects of various vibration parameters (frequency, amplitude and phase difference) on the generation mechanism of typical textured surfaces in 1D and 2D vibration-assisted micro milling. Furthermore, the wettability tests are performed on the machined surfaces with various surface texture topographies. A new contact model, which considers both liquid infiltration effects and air trapped in the microstructure, is proposed for predicting the wettability of the fish scales surface texture. The following surface textures are used for T-shaped and Y-shaped microchannels manufacturing to achieve liquid one-way flow and micro mixer applications, respectively. The liquid flow experiments have been carried out and the results indicate that liquid flow can be controlled effectively in the proposed microchannels at proper inlet flow rates. Burr formation and tool wear suppression mechanisms are studied by using both finite element simulation and experiment methods. A finite element model of vibration assisted micro milling using ABAQUS is developed based on the Johnson-Cook material and damage models. The tool-workpiece separation conditions are studied by considering the tool tip trajectories. The machining experiments are carried out on Ti-6Al-4V with coated micro milling tool (fine-grain tungsten carbides substrate with ZrO2-BaCrO4 (ZB) coating) under different vibration frequencies (high, medium and low) and cutting states (tool-workpiece separation or nonseparation). The results show that tool wear can be reduced effectively in vibration assisted micro milling due to different wear suppression mechanisms. The relationship between tool wear and cutting performance is studied, and the results indicate that besides tool wear reduction, better surface finish, lower burrs and smaller chips can also be obtained as vibration assistance is added.

Electromechanics combines processes from electrical and mechanical systems and focuses on their interactions, which lead to wide applications in modern electronics. The observation of microscale and nanoscale electromechanical phenomena is critical for understanding the underlying physics and inspiring scientific and technological innovations. Near-field scanning microscopy is a promising tool that utilizes evanescent waves to detect local physical properties at a length scale much smaller than the far-field resolution limit. This dissertation demonstrates the discoveries of novel electromechanical phenomena revealed by microwave impedance microscopy (MIM) and shows the invention and application of new scanning microwave microscopy technique inspired by the discoveries. In this dissertation, I first introduce the development of near field scanning probe microscopy. In Chapter 2, I begin by reviewing the basic components and the system design of microwave impedance microscopy (MIM), followed by a description of data analysis and its main application - local conductivity mapping. I then elaborate its other applications in the following chapters, categorized by the different properties probed by the technique. Chapter 3 demonstrates the discovery of a unique phonon mode existing in the ferroelectric domain walls. Chapter 4 shows a novel electromechanical transduction phenomenon in the ferroelectric domains of LiNbO₃. In Chapter 5, I present the invention of a new microwave microscopy technique, transmission-mode MIM (T-MIM), which can be used to visualize the microwave field directly and has achieved great success on mapping surface acoustic wave (SAW). I conclude the thesis in Chapter 6 with a summary of the published discoveries and an outlook of the ongoing projects and future plans in this area.

Research on applicant faking has indicated that faking on personality tests may deteriorate the quality of hiring decisions and affect the validity of personality tests. In order to understand the occurrence of faking, scholars have attempted to explore the psychological process of applicant faking. The general idea is that the ability to fake and the motivation to fake should be two important antecedents of faking. In the current study, the ability to fake is operationally defined as the ability to identify the dimensions being measured in a personality test (i.e., ability to identify criteria (ATIC)). The motivation to fake (i.e., applicant test-taking motivation) is defined based on Valence, Instrumentality and Expectancy (VIE) theory. Study 1 was conducted to explore the nomological framework of ATIC in personality tests, as well as the role of the frame-of-reference on the nature of ATIC ratings. Study 1 found that: (a) ATIC ratings in personality tests were related to verbal, numerical and abstract reasoning ability, but not associated with the construct of self-monitoring; (b) the frame-of-reference had an impact on the ATIC scores such that ATIC scores were higher in a specific personality measure than in a general big five measure; and (c) ATIC ratings across two personality measures also yielded an apparent pattern of cross-measure consistency. Study 2 was conducted to examine the role of the ability to fake and the motivation to fake on faking behavior and the criterion-related validity of personality scores. Results showed that (a) ATIC was not a predictor of faking and it worked to increase the predictive validity of personality scores; whereas (b) the motivation to fake was a predictor of faking and it suppressed the predictive validity of personality scores on GPA. The contributions, practical implications, and future research directions were discussed.

Research has consistently found that pre-warning can reduce faking. This study included four pre-warnings: (1) the detection and consequence warning, (2) reasoning warning, (3) subjective norm warning, and (4) moral conviction warning. Regarding warnings as moral priming, I categorized the detection and consequence warning as proscriptive warning and the others as prescriptive warnings based on the dual moral regulation framework. I had several hypotheses: (1) the use of pre-warnings should reduce applicants’ faking, as well as, enhance the criterion-related validity of personality test; (2) the proscriptive warning should be more effective than the prescriptive warning but had some side effects; and (3) the prescriptive and proscriptive warnings should reduce faking via guilt, shame and fear of punishment. One hundred eighty-two undergraduate students were recruited in the study. Participants completed two parallel forms of personality test, one in a baseline setting and the other in the lab setting. In the lab setting, they were told that they had a chance to apply for a summer internship position while completing a company’s pre-employment assessment. Results showed that: (1) the detection/consequence warning and the subjective norm warning showed acceptable effectiveness in reducing faking; (2) warnings did not influence the criterion-related validity of personality scores; (3) the use of proscriptive warning enhanced participants’ test anxiety and reduced positive affect; and (4) the fear of punishment could reduce faking. The contributions and future research directions were discussed.