Recent advances in microfluidic technologies have enabled integration of the functional units for biological and chemical analysis onto miniaturized chips, called Labon- a-Chip (LOC). However, the effective manipulation and control of colloidal particles suspended in fluids are still challenging tasks due to the lack of clear characterization of particle control mechanisms. The aim of this dissertation is to develop microfluidic techniques and devices for manipulating colloids and biological particles with the utilization of alternating current (AC) electric fields and acoustic waves. The dissertation presents a simple theoretical tool for predicting the motion of colloidal particles in the presence of AC electric field. Dominant electrokinetic forces are explained as a function of the electric field conditions and material properties, and parametric experimental validations of the model are conducted with particles and biological species. Using the theoretical tool as an effective framework for designing electrokinetic systems, a dielectrophoresis (DEP) based microfluidic device for trapping bacterial spores from high conductivity media is developed. With a simple planar electrode having well defined electric field minima that can act as the targetattachment/ detection sites for integration of biosensors, negative DEP trapping of spores on patterned surfaces is successfully demonstrated. A further investigation of DEP colloidal manipulation under the effects of electrothermal flow induced by Joule heating of the applied electric field is conducted. A periodic structure of the electrothermal flow that enhances DEP trapping is numerically simulated and experimentally validated. An acoustic method is investigated for continuous sample concentration in a microscale device. Fast formation of particle streams focused at the pressure nodes is demonstrated by using the long-range forces of the ultrasonic standing waves (USW). High frequency actuation suitable for miniaturization of devices is successfully applied and the device performance and key parameters are explained. Further extension and integration of the technologies presented in this dissertation will enable a chip scale platform for various chemical and biological applications such as drug delivery, chemical analyses, point-of-care clinical diagnosis, biowarfare and biochemical agent detection/screening, and water quality control.

abstract: Otoacoustic emissions (OAEs) are soft sounds generated by the inner ear and can be recorded within the ear canal. Since OAEs can reflect the functional status of the inner ear, OAE measurements have been widely used for hearing loss screening in the clinic. However, there are limitations in current clinical OAE measurements, such as the restricted frequency range, low efficiency and inaccurate calibration. In this dissertation project, a new method of OAE measurement which used a swept tone to evoke the stimulus frequency OAEs (SFOAEs) was developed to overcome the limitations of current methods. In addition, an in-situ calibration was applied to equalize the spectral level of the swept-tone stimulus at the tympanic membrane (TM). With this method, SFOAEs could be recorded with high resolution over a wide frequency range within one or two minutes. Two experiments were conducted to verify the accuracy of the in-situ calibration and to test the performance of the swept-tone SFOAEs. In experiment I, the calibration of the TM sound pressure was verified in both acoustic cavities and real ears by using a second probe microphone. In addition, the benefits of the in-situ calibration were investigated by measuring OAEs under different calibration conditions. Results showed that the TM pressure could be predicted correctly, and the in-situ calibration provided the most reliable results in OAE measurements. In experiment II, a three-interval paradigm with a tracking-filter technique was used to record the swept-tone SFOAEs in 20 normal-hearing subjects. The test-retest reliability of the swept-tone SFOAEs was examined using a repeated-measure design under various stimulus levels and durations. The accuracy of the swept-tone method was evaluated by comparisons with a standard method using discrete pure tones. Results showed that SFOAEs could be reliably and accurately measured with the swept-tone method. Comparing with the pure-tone approach, the swept-tone method showed significantly improved efficiency. The swept-tone SFOAEs with in-situ calibration may be an alternative of current clinical OAE measurements for more detailed evaluation of inner ear function and accurate diagnosis. / Dissertation/Thesis / Ph.D. Speech and Hearing Science 2012

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18768号 / 理博第4026号 / 新制||理||1580(附属図書館) / 31719 / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)教授 堤 誉志雄, 教授 上田 哲生, 教授 加藤 毅 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Improving energy efficient lighting is a necessary step in reducing energy consumption.Lighting currently consumes 17% of all U.S. residential and commercial electricity, but a report from the U.S. Office of Energy Efficiency and Renewable Energy projects that switching to LED lighting over the next 20 years will save 46% of electricity used in lighting.GaN LEDs are used for their efficient conversion of electricity to light, but improving GaN efficiency requires optically engineering the chip to extract more light.Total internal reflection limits GaN LED performance since light must approach the chip surface within 23.6° of normal to escape into air.This thesis systematically studies the effect of index of refraction, material thickness, and nano-grating period on light extraction efficiency.An ITO layer is added to the LED surface to increase the critical angle of light, and standing wave analysis is used to optimize material thicknesses.When these results are combined with the best grating period, light output improves by 254% over the unmodified LED.

Continuous chromatography is an attractive alternative to traditional batch chromatography because it can have higher productivity, solvent efficiency, and product concentrations. However, several barriers prevent further use of continuous chromatography. There are many operating parameters that must be determined when designing continuous systems making it difficult to achieve high purity, yield, and productivity. Through the identification and strategic combination of the key dimensionless groups that control a continuous separation, it is possible to design highly productive systems that produce products with high yield and high purity. In this dissertation, three examples were selected to demonstrate the significance of a model-based method when designing continuous chromatography systems. (1) The Speedy Standing Wave Design and simulated moving bed splitting strategies for the separation of ternary mixtures with linear isotherms. (2) The Standing-wave Design of Three-Zone open-loop non-isocratic SMB for purification. (3) The Continuous Ligand-Assisted Displacement for the separation of Rare Earth Elements.<div>In the first example, the Speedy Standing Wave Design equations were developed for multicomponent separations with linear isotherms and a systematic splitting strategy was developed for the design of multiple sequential Simulated Moving Beds (SMBs). By performing the easiest split first, the overall productivity and solvent efficiency can be significantly improved. Rate model simulations were used to verify that the SSWD equations achieved target yields and purities. In systems where only one component is desired, the sorbent should be selected such that this component is the most or least retained so that it can be separated in a single SMB.</div><div>In the second example, the Standing Wave Design method was extended to non-isocratic three zone open loop SMBs. The standing wave design equations were derived and then verified using rate model simulations. In two case studies it was shown that non-isocratic SMBs designed using the standing wave design method show an order of magnitude higher productivity than a comparable batch system when the impurities are weakly adsorbing. When the impurities are competitive, the SWD method produces SMB systems with 2 orders of magnitude higher productivity than comparable batch systems. Because the design is based on dimensionless groups, the resulting designs are easily scalable and no rate model simulations are required to design high yield, high purity, and high productivity SMBs.</div><div>In the third example, the constant pattern design method was extended to continuous LAD systems. A continuous operation mode was developed that reduced the cycle time of LAD systems to further increase the productivity. In cases where the feed was equimolar, the continuous configuration increased the productivity between 20-50%. A multizone continuous LAD configuration was developed for the separation of a complex mixture of Dy, ND, and Pr that simulated a crude magnet feed. The resulting overall productivity for this system was 190 kg/m³day which was two orders of magnitude higher than a single column batch system and 70% higher than a multizone batch system. The robustness of the constant pattern design method was demonstrated through a simulated case study and it was determined that adding a safety factor through the reduction of the flowrate was more effective than reducing the design length.</div><div>Using a model-based design allows for the consistent design of continuous chromatography systems. The effects of a change in a feed or operating condition can be more easily understood through the lens of the model. This means that adjustments can be made pre-emptively when necessary and the new designs can be tested with virtual experiments before being implemented. The understanding of key dimensionless groups allows for designs that meet key design criteria at all scales of operation and thus allows for the easy transition from one scale to another.</div>

Previously, we proposed and experimentally demonstrated that optical cavities can be employed in recording and readout of plane wave holograms to improve data rates in Holographic Data Storage Systems (HDSS). However, there were some concerns about whether these techniques would be applicable to page based HDSS where signal beams are image bearing and have multiple wave vectors. We have consequently demonstrated cavity enhanced writing of image bearing holograms in Fe: LiNbO3 with a 532 nm wavelength, CW, single mode, DPSS, Nd: YAG, laser with a cavity on the reference arm. The diffraction efficiency was monitored by pseudo-phase-conjugate readout during the recording process. Additionally, standing wave cavity recording was described as inappropriate to HDSS due to introducing additionally gratings to the recording process. The balancing of these grating strengths is analyzed relative to a trade-off in dynamic range consumption vs. data rates and the elimination of the extra gratings via quarter wave plates and isotropic recording media is proposed.

Coupled nonlinear Schrodinger equations (CNLS) govern many physical phenomena, such as nonlinear optics and Bose-Einstein condensates. For their wide applications, many studies have been carried out by physicists, mathematicians and engineers from different respects. In this dissertation, we focused on standing wave solutions, which are of particular interests for their relatively simple form and the important roles they play in studying other wave solutions. We studied the multiplicity of this type of solutions of CNLS via variational methods and bifurcation methods. Variational methods are useful tools for studying differential equations and systems of differential equations that possess the so-called variational structure. For such an equation or system, a weak solution can be found through finding the critical point of a corresponding energy functional. If this equation or system is also invariant under a certain symmetric group, multiple solutions are often expected. In this work, an integer-valued function that measures symmetries of CNLS was used to determine critical values. Besides variational methods, bifurcation methods may also be used to find solutions of a differential equation or system, if some trivial solution branch exists and the system is degenerate somewhere on this branch. If local bifurcations exist, then new solutions can be found in a neighborhood of each bifurcation point. If global bifurcation branches exist, then there is a continuous solution branch emanating from each bifurcation point. We consider two types of CNLS. First, for a fully symmetric system, we introduce a new index and use it to construct a sequence of critical energy levels. Using variational methods and the symmetric structure, we prove that there is at least one solution on each one of these critical energy levels. Second, we study the bifurcation phenomena of a two-equation asymmetric system. All these bifurcations take place with respect to a positive solution branch that is already known. The locations of the bifurcation points are determined through an equation of a coupling parameter. A few nonexistence results of positive solutions are also given

This Master Thesis examines the possibility to apply a magnetometer developed by the Ångstöm space technology center to a small magnetic ground penetrating radar system with dimension in the order of one dm³. The magnetometer is broadband (DC-1GHz) and miniaturized. Loop antennas are used to transmit the signal.    A series of experiments have been performed in order to characterize the system, mainly examining the ability to determine distance to a target, using continuous sine wave signals and pulse trains. Standing wave patterns are formed between antenna and target and can be used for determining distance in the continuous case. When using a pulse train, the echo from the target could not be resolved using the current experiment set up, distance could therefore not be determined.

The real phenomena of sea surface are interacting by much kind of different waves.In these phenomena, the gravity standing wave is most important. The gravity standing wave is formed by two progressive waves that possessing same properties but opposite directions. Gravity standing wave can also form by the interaction of a progressive wave with it¡¦s totally reflection wave. Because of the nonlinear interaction of two waves, there must result a double-crest phenomenon of wave pressure. It is dangerous for the navigation of ship when the double-crest appears, and it¡¦s certainly to take the phenomenon into consideration when we are going to design a jetty. In this paper, it bases on the reference of Chen (1989, 1990) who obtained a third-order approximation of two-wave trains interactions in a uniform depth wave field. Further, in this paper, it checks the result that the double-crest phenomenon is formed by which one of these nonlinear terms. Furthermore, research the influences of wave steepness, wave periods, and water depths these factors will cause the crest diverges is also the purpose.

Concentration of microorganisms from a sample volume would increase the limits of detection of samples used for rapid-detection methods. Rapid detection methods are is advantageous for the food industry to rapidly test for bacteria in order release products on a timely basis. Ultrasonic concentration was considered a promising method for manipulation of microorganisms. An ultrasonic chamber consisting of parallel piezoceramic discs with a reticulated polyurethane foam mesh was used to concentrate Saccharomyces cerevisiae yeast and Escherichia coli bacteria. The concentration of yeast was seen to increase by 200% (from 8.0 x 104 cells mL-1 to 2.4 x 105 cells mL-1) while almost zero concentration of bacteria was observed. The poor concentration effect seen with the smaller microorganisms was explained by the volume dependent acoustic radiation force exerted on the particles; the concentration forces are 1,000 times smaller for a 1 μm bacteria cell versus a 10 μm yeast cell.