Eagle’s syndrome is a collection of symptoms caused by styloid process elongation or calcification of the stylohyoid ligament, measuring more than 2.5 centimeters. It is a radio-clinical entity characterized by a het...Eagle’s syndrome is a collection of symptoms caused by styloid process elongation or calcification of the stylohyoid ligament, measuring more than 2.5 centimeters. It is a radio-clinical entity characterized by a heterogeneous polymorphic symptomatology most often involving headaches, facial pain, dysphagia and a foreign body sensation in the throat. Its management is mainly surgical. It is a rarely diagnosed condition in children. Here we report a typical case of Eagle’s syndrome which was diagnosed in a 14-year-old child with a history of chronic right unilateral pharyngeal discomfort, odynophagia and oropharyngeal foreign body sensation. CT scan showed a long left styloid process. The patient underwent surgical removal of the elongated styloid process externally. The outcome was favorable after surgery.展开更多
A bifacial silicon solar cell under monochromatic illumination in frequency modulation by the rear side is being studied for the optimization of base thickness. The density of photogenerated carriers in the base is ob...A bifacial silicon solar cell under monochromatic illumination in frequency modulation by the rear side is being studied for the optimization of base thickness. The density of photogenerated carriers in the base is obtained by resolution of the continuity equation, with the help of boundary conditions at the junction surface (n<sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">/p) and the rear face (p/p</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">) of the base. For a short wavelength corresponding to a high absorption coefficient, the AC photocurrent density is calculated and represented according to the excess minority carrier’s recombination velocity at the junction, for different modulation frequency values. The expression of the AC recombination velocity of excess minority carriers at the rear surface of the base of the solar cell is then deduced, depending on both, the absorption coefficient of the silicon material and the thickness of the base. Compared to the intrinsic AC recombination velocity, the optimal thickness is extracted and modeled in a mathematical relationship, as a decreasing function of </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">modulated frequency of back illumination. Thus under these operating conditions</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> a maximum short-circuit photocurrent is obtained and a low</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">cost bifacial solar cell can be achieved by reducing material (Si) to elaborate the base thickness.</span>展开更多
Excess minority carrier’s diffusion equation in the base of monofaciale silicon solar cell under frequency modulation of monochromatic illumination is resolved. Using conditions at the base limits involving recombina...Excess minority carrier’s diffusion equation in the base of monofaciale silicon solar cell under frequency modulation of monochromatic illumination is resolved. Using conditions at the base limits involving recombination velocities <i>Sf</i> and <i>Sb</i>, respectively at the junction (n<sup>+</sup>/p) and back surface (p<sup>+</sup>/p), the AC expression of the excess minority carriers’ density <i>δ</i> (<i>T</i>, <i>ω</i>) is determined. The AC density of photocurrent <i>J<sub>ph</sub></i> (<i>T</i>, <i>ω</i>) is represented versus recombination velocity at the junction for different values of the temperature. The expression of the AC back surface recombination velocity <i>Sb</i> of minority carriers is deduced depending on the frequency of modulation, temperature, the electronic parameters (<i>D</i> (<i>ω</i>)) and the thickness of the base. Bode and Nyquist diagrams are used to analyze it.展开更多
The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial developm...The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (<em>D</em>(<em>ω</em>, <em>B</em>), in the (<em>p</em>) base leads to maximum values (Dmax) at resonance frequencies (<em>ωr</em>). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, <em>ωr</em> and <em>B</em>, are then established, and will be data for industrial development of low-cost solar cells for specific use.展开更多
文摘Eagle’s syndrome is a collection of symptoms caused by styloid process elongation or calcification of the stylohyoid ligament, measuring more than 2.5 centimeters. It is a radio-clinical entity characterized by a heterogeneous polymorphic symptomatology most often involving headaches, facial pain, dysphagia and a foreign body sensation in the throat. Its management is mainly surgical. It is a rarely diagnosed condition in children. Here we report a typical case of Eagle’s syndrome which was diagnosed in a 14-year-old child with a history of chronic right unilateral pharyngeal discomfort, odynophagia and oropharyngeal foreign body sensation. CT scan showed a long left styloid process. The patient underwent surgical removal of the elongated styloid process externally. The outcome was favorable after surgery.
文摘A bifacial silicon solar cell under monochromatic illumination in frequency modulation by the rear side is being studied for the optimization of base thickness. The density of photogenerated carriers in the base is obtained by resolution of the continuity equation, with the help of boundary conditions at the junction surface (n<sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">/p) and the rear face (p/p</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">) of the base. For a short wavelength corresponding to a high absorption coefficient, the AC photocurrent density is calculated and represented according to the excess minority carrier’s recombination velocity at the junction, for different modulation frequency values. The expression of the AC recombination velocity of excess minority carriers at the rear surface of the base of the solar cell is then deduced, depending on both, the absorption coefficient of the silicon material and the thickness of the base. Compared to the intrinsic AC recombination velocity, the optimal thickness is extracted and modeled in a mathematical relationship, as a decreasing function of </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">modulated frequency of back illumination. Thus under these operating conditions</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> a maximum short-circuit photocurrent is obtained and a low</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">cost bifacial solar cell can be achieved by reducing material (Si) to elaborate the base thickness.</span>
文摘Excess minority carrier’s diffusion equation in the base of monofaciale silicon solar cell under frequency modulation of monochromatic illumination is resolved. Using conditions at the base limits involving recombination velocities <i>Sf</i> and <i>Sb</i>, respectively at the junction (n<sup>+</sup>/p) and back surface (p<sup>+</sup>/p), the AC expression of the excess minority carriers’ density <i>δ</i> (<i>T</i>, <i>ω</i>) is determined. The AC density of photocurrent <i>J<sub>ph</sub></i> (<i>T</i>, <i>ω</i>) is represented versus recombination velocity at the junction for different values of the temperature. The expression of the AC back surface recombination velocity <i>Sb</i> of minority carriers is deduced depending on the frequency of modulation, temperature, the electronic parameters (<i>D</i> (<i>ω</i>)) and the thickness of the base. Bode and Nyquist diagrams are used to analyze it.
文摘The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (<em>D</em>(<em>ω</em>, <em>B</em>), in the (<em>p</em>) base leads to maximum values (Dmax) at resonance frequencies (<em>ωr</em>). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, <em>ωr</em> and <em>B</em>, are then established, and will be data for industrial development of low-cost solar cells for specific use.
