Panasonic (China)

The pH of brewing water plays a significant role in shaping the microstructure of tea leaves, thereby affecting the flavor profile of green tea infusions. In this study, green tea was brewed using water with seven different pH levels to examine microstructural alterations and their impact on flavor quality. Results showed that the contents of total volatile compounds, tea polyphenols, and soluble sugars initially decreased and then increased with rising water pH, a trend consistent with changes in the degree of tea leaf damage. This indicates that the damage status of the leaves considerably influenced the release of these flavor components. Sensory evaluation revealed notable differences among infusions: T1, derived from the most severely damaged leaves, exhibited the strongest floral aroma, while T7 had the most intense chestnut aroma along with a dull odor. Both T1 and T7 also showed prominent bitterness and astringency. Partial least squares discriminant analysis (PLS-DA) identified 19 key flavor compounds contributing significantly to aroma profiles. Further partial least squares regression (PLSR) analysis correlated high concentrations of 1-hexadecanol, dodecanal, acetic acid, and nonanal in low-pH infusions with clean, refreshing, and flowery aroma, whereas diisobutyl phthalate was associated with dull odor. These findings offer important insights into how brewing water pH modulates the physicochemical and sensory properties of green tea.

To investigate the combined effects of sodium and potassium on thermal conductivity, a series of borosilicate glasses with precise compositions (65.0SiO2·5.0B2O3 (17.6 - x)Na2O·xK2O·7.5CaO·4.9MgO) was synthesized, where R = [K2O]/([Na2O] + [K2O]). As R increased systematically, a pronounced nonlinear variation in thermal conductivity, characteristic of the mixed alkali effect, was observed. Within the phonon gas model framework, the thermal conductivity was primarily governed by changes in sound velocity, as both volumetric heat capacity and phonon mean free path remained nearly constant across the glass series. NMR and Raman spectra revealed nonlinear evolution in the local coordination environment of silicon cations with increasing R. These structural changes, coupled with anomalous variations in atomic packing fractions, provided atomic-scale evidence for the observed thermal conductivity trends. This study not only deepens the understanding of the physical mechanisms governing thermal properties in borosilicate glasses but also provides valuable insights for designing advanced materials with precisely tailored thermal performance.

La conflictividad entre pares y los modos violentos de circulación entre estudiantes adolescentes continúan siendo una problemática frecuente en las escuelas latinoamericanas (Banz, 2008, Kaplan, 2020). Si bien en los últimos años se han multiplicado normativas y programas para promover la convivencia escolar, son menos frecuentes las investigaciones que indaguen en profundidad las dinámicas grupales entre estudiantes y sus propias subjetividades en torno a los conflictos interpersonales que atraviesan cotidianamente. En el contexto educativo actual, los conflictos escolares representan un desafío significativo que afecta el bienestar de estudiantes, docentes y el entorno educativo en general. La prevalencia de enfoques tradicionales para abordar estos conflictos ha llevado a la necesidad de explorar e implementar estrategias más efectivas y centradas en el diálogo para la resolución no violenta de estos conflictos. Uno de los desafíos identificados es la falta de herramientas pedagógicas especializadas que promuevan la comunicación abierta, la comprensión mutua y la construcción de soluciones colaborativas en situaciones conflictivas dentro del ámbito escolar. La ausencia de métodos específicos basados en el diálogo podría estar relacionada con el aumento de tensiones, hostilidades y disrupciones, lo cual podría influir negativamente en el clima escolar y el rendimiento académico. En consonancia, se propone analizar, desde una perspectiva cualitativa, los significados, percepciones y posicionamientos que construyen aprendices del Centro de Industria y Construcción (CIC) Regional Tolima del Servicio Nacional de Aprendizaje SENA en torno a situaciones de violencia y conflicto con sus pares dentro del ámbito escolar durante el ciclo lectivo 2023. Asimismo, se busca identificar potencialidades y obstáculos a la hora de implementar estrategias dialógicas y no violentas para la resolución de conflictos interpersonales, desde la mirada situada de estos actores escolares. Esta investigación buscará abordar esta brecha identificada, centrándose en el desarrollo e implementación de estrategias dialógicas. Se pretende investigar cómo estas estrategias pueden ser diseñadas e integradas de manera efectiva en el entorno educativo para promover una resolución no violenta de conflictos, fomentando así un ambiente escolar más armonioso y propicio para el aprendizaje. La finalidad es aportar insumos que permitan repensar y mejorar los modos de intervenir pedagógicamente sobre esta problemática, apuntando a la construcción entre todos los miembros de la comunidad educativa de una convivencia más pacífica, democrática e inclusiva.

This paper delves into the prevalence of educational inequality in China, conducting an in-depth analysis of existing academic articles, government reports, and policy documents. It explores the intricate mechanisms that underlie the disparities in education, particularly how geographic, socio-economic, and structural factors contribute to these gaps across regions and demographics. The study pays particular attention to the impact of family background, socio-economic status, and geographical location, identifying these as the main drivers of educational inequality in China. Through a rigorous and systematic review of the literature, the study reveals the nuanced and complex interplay of history, policy, and socio-economic dynamics on educational outcomes. The findings highlight the significant disparities, especially between urban and rural areas, where the hukou system and unequal access to educational resources exacerbate the issue. This comprehensive literature analysis not only sheds light on the complex landscape of educational inequality in China but also informs the discussion on potential policy interventions that can be implemented to promote a more equitable educational environment. The study's insights are crucial for policymakers, educators, and researchers alike in their efforts to address this pressing issue and ensure that all children in China have access to quality education, regardless of their background or location.

耐熱性に優れた16種類の感応膜（PCM）とマイクロヒータからなる高感度でコンパクトな熱制御人工嗅覚システム（TC-OSS）を開発した．TC-OSSを用いて臭気強度2相当の5種類の基準VOCsを測定した．得られた5クラス×40データについて，応答波形から算出した特徴量（高さや傾きなど）をもとに，機械学習による学習モデルを構築した．学習モデルの精度をクロスバリデーション（繰り返し回数＝100）により評価した結果，95.8±2.7%の高い正答率で識別に成功した．

Check valve is one of the core components of the scroll refrigeration compressor, which can directly affect its efficiency, life, and noise performance. Traditional check valve is the reed valve. This paper deeply studies the dynamic characteristics of reed valve and reveals the main reason of the valve noise under different rotation speeds. The large noise is mainly attributing to the large pressure pulsation as well as fast circulation velocity of fluid and the severe slapping of the reed plate on the valve seat, which is influenced by the high pressure ratio of the working condition and stiffness of the reed valve. In order to reduce the noise of the check valve, the circular valve is designed to replace reed valve in this paper. At each rotation speed, the circular valve shows a continuous exhaust process, which avoids the slapping of the valve plate on the valve seat. More importantly, the exhaust is smooth and the pressure pulsation as well as the flow rate of the fluid is reduced significantly leading to the low aerodynamic noise. Therefore, compared with the reed valve compressor, the sound pressure level of the circular valve compressor at 1800, 4200, and 6600 rpm is decreased by 3.0, 5.2, and 0.3 dB, respectively.

Electrochemical impedance spectroscopy (EIS) enables the examination of the electrochemical nature of electrodes and electrochemical cells by applying an alternating voltage (or current) and measuring the resulting current (or voltage). The resistance and capacitance components of the electrode can be evaluated by applying an AC voltage and changing the frequency. In particular, analysis using the equivalent circuit can determine important parameters related to the electrochemical reaction of the electrode, such as the charge transfer resistance, electric double-layer capacitance, and Warburg impedance. Moreover, the internal resistance of the cell can be divided into resistances caused by the positive electrode, negative electrode, and electrolyte. Because of these advantages, EIS is a powerful technique used for basic research, such as in identifying the rate-determining step of an electrochemical reaction, and also for applied research, such as characterizing electrochemical devices (e.g., batteries and capacitors). In this paper, the concept of impedance, which represents the relationship between the AC voltage and current, is first explained; then, the AC characteristics of various circuit elements used in equivalent circuits, which are essential for understanding EIS, are described. Finally, treatments of more complex circuits based on transmission-line models (TLMs), which are used to represent equivalent circuits of porous electrodes, are presented. Analyses based on TLMs are the foundation for understanding electrodes for practical applications because porous electrodes are usually used in electrochemical devices.