The theoretical study of passive and active optical devices via planewave based transfer (scattering) matrix method and other approaches

In this thesis, we theoretically study the electromagnetic wave propagation in several passive and active optical components and devices including 2-D photonic crystals, straight and curved waveguides, organic light emitting diodes (OLEDs), and etc. Several optical designs are also presented like organic photovoltaic (OPV) cells and solar concentrators. The first part of the thesis focuses on theoretical investigation. First, the plane-wave-based transfer (scattering) matrix method (TMM) is briefly described with a short review of photonic crystals and other numerical methods to study them (Chapter 1 and 2). Next TMM, the numerical method itself is investigated in details and developed in advance to deal with more complex optical systems. In chapter 3, TMM is extended in curvilinear coordinates to study curved nanoribbon waveguides. The problem of a curved structure is transformed into an equivalent one of a straight structure with spatially dependent tensors of dielectric constant and magnetic permeability. In chapter 4, a new set of localized basis orbitals are introduced to locally represent electromagnetic field in photonic crystals as alternative to planewave basis. The second part of the thesis focuses on the design of optical devices. First, two examples of TMM applications are given. The first example is the design of metal grating structures as replacements of ITO to enhance the optical absorption in OPV cells (chapter 6). The second one is the design of the same structure as above to enhance the light extraction of OLEDs (chapter 7). Next, two design examples by ray tracing method are given, including applying a microlens array to enhance the light extraction of OLEDs (chapter 5) and an all-angle wide-wavelength design of solar concentrator (chapter 8). In summary, this dissertation has extended TMM which makes it capable of treating complex optical systems. Several optical designs by TMM and ray tracing method are also given as a full complement of this work

Comparative study of microwave radiation-induced magnetoresistive oscillations induced by circularly- and linearly- polarized photo-excitation

A comparative study of the radiation-induced magnetoresistance oscillations in the high mobility GaAs/AlGaAs heterostructure two dimensional electron system (2DES) under linearly- and circularlypolarized microwave excitation indicates a profound difference in the response observed upon rotating the microwave launcher for the two cases, although circularly polarized microwave radiation induced magnetoresistance oscillations observed at low magnetic fields are similar to the oscillations observed with linearly polarized radiation. For the linearly polarized radiation, the magnetoresistive response is a strong sinusoidal function of the launcher rotation (or linear polarization) angle, {\theta}. For circularly polarized radiation, the oscillatory magnetoresistive response is hardly sensitive to {\theta}

A simple and sensitive method for determination of Norfloxacin in pharmaceutical preparations

;Propos-se, por essa abordagem, novo método voltamétrico, com alta sensibilidade e faixa linear de detecção mais ampla, para a determinação de norfloxacino. O sensor voltamétrico utilizado foi fabricado simplismente por cobertura de camada de óxido de grafeno (GO) e filme de Nafion em eletrodo de cabrono vítreo. A vantagem do método proposto foi a resposta eletroquímica sensível para o norfloxacino, atribuída à condutividade elétrica excelente do GO e à função acumulada do Nafion. Sob condições experimentais ótimas, o presente método revelou boa resposta linear para a determinação do norfloxacino na faixa de limite de detecção de 1×10;-8;mol/L-7×10;-6; mol/L. O método proposto foi aplicado com sucesso na determinação de norfloxacino em cápsulas, com resultados satisfatórios.;;In this approach, a new voltammetric method for determination of norfloxacin was proposed with high sensitivity and wider detection linear range. The used voltammetric sensor was fabricated simply by coating a layer of graphene oxide (GO) and Nafion composited film on glassy carbon electrode. The advantage of proposed method was sensitive electrochemical response for norfloxacin, which was attributed to the excellent electrical conductivity of GO and the accumulating function of Nafion under optimum experimental conditions, the present method revealed a good linear response for determination of norfloxacin in the range of 1×10;-8;mol/L-7×10;-6; mol/L with a detection limit of 5×10;-9; mol/L. The proposed method was successfully applied in the determination of norfloxacin in capsules with satisfactory results.

Local track irregularity identification based on multi-sensor time-frequency features of high-speed railway bridge accelerations

Shortwave track diseases are generally reflected in the form of local track irregularity. Such diseases will greatly impact the train-track-bridge interaction (TTBI) dynamic system, seriously affecting train safety. Therefore, a method is proposed to detect and localize local track irregularities based on multis-sensor time-frequency features of high-speed railway bridge accelerations. Continuous wavelet transform (CWT) is used to analyze the multi-sensor accelerations of railway bridges. Moreover, time-frequency features based on the sum of wavelet coefficients are proposed, considering the influence of the distance from the measurement points to the local irregularity on the recognition accuracy. Then, the multi-domain features are utilized to recognize deteriorated railway locations. A simply-supported high-speed railway bridge traversed by a railway train is adopted as a numerical simulation. Comparative studies are conducted to investigate the influence of vehicle speeds and the location of local track irregularity on the algorithm. Numerical simulation results show that the proposed algorithm can detect and locate local track irregularity accurately and is robust to vehicle speeds

Effectiveness of Ultrasound-Guided Minimally Invasive Spinotomy in the Treatment of Multiple Small Benign Breast Nodules

Objective: To observe the efficacy of different surgical protocols in the management of multiple benign breast nodules. Methods: Patients diagnosed with multiple benign breast nodules from 2021.4 to 2023.2 were divided into two groups, blank and study groups, each with 51 cases, and treated with conventional open and ultrasound-guided minimally invasive rotational surgery respectively. Results: The study group had better incision diameter and VAS score at 24h postoperatively than the blank group, with significant differences (P < 0.05). Regarding the postoperative complication rate index, the study group vs. the blank group was 3.92% vs. 21.57% (P < 0.05). Conclusion: Minimally invasive spinotomy under ultrasound guidance for the treatment of patients with multiple breast nodules is safe and effective and has the potential to be used universally

Analysis of Clinical Efficacy of Single-Port Endoscopic Breast-Conserving Surgery and Modified Radical Mastectomy in the Treatment of Early Breast Cancer

Objective: To analyze the effect of single-port endoscopic breast-conserving surgery and modified radical mastectomy in the treatment of early breast cancer. Methods: The research subjects included in this study were 52 patients with early breast cancer who were admitted to our hospital from February 2020 to February 2021. They were divided into control group and experimental group by random number table method. The control group received modified radical mastectomy(26 cases), and the experimental group received single-port endoscopic breast-conserving surgery (26 cases). The treatment effects of the two groups were compared. Results: The blood loss, incision length and hospital stay in the experimental group were lower than those in the control group (P<0.05), but the operation time was significantly longer than that in the control group (P<0.05). There were significant differences in breast beauty between the two groups, and the experimental group was better (P<0.05). Conclusion: Single-port endoscopic breast-conserving surgery and modified radical mastectomy are used in the treatment of early breast cancer, and the treatment effect of the former is significantly better than that of the latter. This treatment method can be promoted

Analysis of the Effectiveness of Globe Incision Mammaplasty in the Treatment of Early Breast Cancer

Objective: To observe the efficacy of different methods in the treatment of early stage breast cancer disease. Methods: 84 patients admitted from 2020.12 to 2022.8 were divided into groups I and II, 42 patients each, who received treatment after conventional breast-conserving and racket-shaped incision mammoplasty, respectively, and compared the surgical treatment of patients between groups. Results: The rates of cosmetic excellence and complications in group II were 95.2% and 7.1% respectively, compared with 73.8% and 35.7% in group I. The differences reached a significant level (X² 5.825,8.556 respectively, P equals 0.016,0.003 both <0.05). Conclusion: The treatment of early breast cancer patients with racket-shaped incisions for mammaplasty is cosmetically effective and safe, and is worth promoting