3,531 research outputs found

    Experimental Investigation on the Influence of the Oil Return Hole on the Performance of R-32 Wet Compression Cycle

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    R-32 has been being one of the hot candidate for refrigerant substitute because of its better thermodynamic performance. In this study, the influence of wet compression on R-32 system performance was researched by theoretical analysis and experimental test firstly. The result showed that, with the suction dryness decreasing, the discharge temperature,and the volumetric efficiency, and the system performance decreased simultaneously. And then, on the base of the wet compression experiment test, the influence of the oil return hole in the gas-liquid separator on system performance of R32 wet compression was compared. The experimental results showed that, in wet compression, the decreasing rate, that the cooling capacity and EER decreased with the discharge temperature decreasing, decreased with the size of the oil return hole increasing. The increase of the oil return hole size was benefit to improve the system performance in wet compression. But it increased the risk of over wet compression or liquid impact for compressor under frosting and defrosting condition

    Ellipsometry and Its Applications in Stoichiometry

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    Dynamic Investigation of Thermal Behavior in a Hot Water Storage Tank

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    Air Source Heat Pump Water Heater is an environmental –friendly technology with high efficiency. The thermal behavior of water in the storage tank has great importance for designing a more energy-saving control strategy. In this study, the time-dependent temperature distributions during typical transient processes including heating up and tapping processes are studied with a 3D CFD model of the water storage tank in a cyclic heat pump water heater. The simulated temperature profiles in the heating up period were in good agreement with the experimental results. Different initial conditions were tested in the heating up periods, and they had little influence on the final temperature profiles in a practical water tank. The influences of varied flow rates and supply water temperatures were studied in the tapping stages. The thermocline was shortened when the temperatures in the bottom were higher and the flow rates were larger. Finally, the possibility to calculate the flow rates from the temperature changes was discussed

    Health Benefits of Theanine in Green Tea: A Review

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    Theanine is an amide exclusively present in tea and some fungi, and is an important bioactive component of tea. The bioactive effects of theanine include antitumour, anti-diabetic, antihypertensive, anti-stress activities, and the ability to improve cardiovascular and cerebrovascular diseases. It also has protective effect on nerve cells against damage induced by environmental neurotoxins as well as on liver from injury induced by excessive alcohol intake. The bioactive functions of theanine as well as its pharmacokinetics are presented in this review.Keywords: Theanine, Pharmacokinetics, Pharmacology, Bioactive propertie

    Expressions of ECE-CYC2 clade genes relating to abortion of both dorsal and ventral stamens in Opithandra (Gesneriaceae)

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    <p>Abstract</p> <p>Background</p> <p>ECE-CYC2 clade genes known in patterning floral dorsoventral asymmetry (zygomorphy) in <it>Antirrhinum majus </it>are conserved in the dorsal identity function including arresting the dorsal stamen. However, it remains uncertain whether the same mechanism underlies abortion of the ventral stamens, an important morphological trait related to evolution and diversification of zygomorphy in Lamiales <it>sensu lato</it>, a major clade of predominantly zygomorphically flowered angiosperms. <it>Opithandra </it>(Gesneriaceae) is of particular interests in addressing this question as it is in the base of Lamiales <it>s.l</it>., an early representative of this type zygomorphy.</p> <p>Results</p> <p>We investigated the expression patterns of four ECE-CYC2 clade genes and two putative target <it>cyclinD3 </it>genes in <it>Opithandra </it>using RNA <it>in situ </it>hybridization and RT-PCR. <it>OpdCYC </it>gene expressions were correlated with abortion of both dorsal and ventral stamens in <it>Opithandra</it>, strengthened by the negatively correlated expression of their putative target <it>OpdcyclinD3 </it>genes. The complement of <it>OpdcyclinD3 </it>to <it>OpdCYC </it>expressions further indicated that <it>OpdCYC </it>expressions were related to the dorsal and ventral stamen abortion through negative effects on <it>OpdcyclinD3 </it>genes.</p> <p>Conclusion</p> <p>These results suggest that ECE-CYC2 clade TCP genes are not only functionally conserved in the dorsal stamen repression, but also involved in arresting ventral stamens, a genetic mechanism underlying the establishment of zygomorphy with abortion of both the dorsal and ventral stamens evolved in angiosperms, especially within Lamiales <it>s.l</it>.</p

    9-(2-Thien­yl)-9H-carbazole

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    In the title compound, C16H11NS, the dihedral angles between the fused ring system and the pendant thienyl ring are 86.37 (5) and 57.14 (5)°

    Protective effect of (-)-epigallocatechin gallate on ultraviolet b-induced skin damage in hairless mice

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    Purpose: To investigate the protective effect of green tea (-)-epigallocatechin gallate (EGCg) on ultraviolet B (UV-B)-induced skin damages in hairless mice in order to develop a natural sunscreen compound for use in skin care products and cosmetics.Methods: EGCg was dissolved in acetone at concentrations of 1.0, 10.0 and 50.0 mg/mL, and topically applied to the skin of hairless mice at doses of 0.2 mL/cm2, with acetone as control. The mice were then irradiated by 100 μW/cm2 UV-B for 30 min daily. EGCg treatment and UV-B irradiation were carried out daily for 28 consecutive days. The mice were then sacrificed and their dorsal skin examined by transmission electron microscopy (TEM) on the 28th day.Results: UV-B irradiation induced severe macroscopic skin damage including chapping, cracking and abnormal desquamation in the treated hairless mice. EGCg showed dose-dependent protective effects against UV-B induced damage on the skin. Treatments with 10.0 and 50.0 mg/mL EGCg alleviated UVB- induced skin damage by suppressing both keratinocyte apoptosis and mitochondrial dysfunction, along with inhibiting the production of melanin pigment.Conclusion: Topical application of green tea EGCg shows dose-dependent protective effect against UV-B-induced damage on hairless mouse skin. Thus, the plant compound can potentially be used as an alternative agent for photoprotection against UV-B exposure.Keywords: UV-B, Green tea EGCg, Photoprotection, Stratum corneum,  Mitochondrion, Melanosom

    Non-Abelian Collective Excitations in Unlinearized Quark-Gluon Plasma Media

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    We study the effect of unlinearized medium on the collective excitations in quark-gluon plasma. We present two kinds of non-Abelian oscillation solutions which respectively correspond to weakly and strongly nonlinear coupling of field components in color space. We also show that the weakly nonlinear solution is similar to Abelian-like one but has the frequency shift, which is of order g2Tg^2T, from eigenfrequency.Comment: 7 page

    Quantitative assessment of otitis media with effusion with scanning laser Doppler vibrometer - A preliminary study

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    Otitis media with effusion (OME) is a common middle ear inflammation for preschool-age children, with the presence of fluid in the middle ear cavity (MEC). Although the biomechanical abnormalities induced by OME has been evaluated by many studies through measuring the vibration pattern of the tympanic membrane (TM), the precise and quantitative assessment of severity at different stages of OME is still not fully achieved, and the diagnosis still largely depends on the subjective rating of physicians. To provide reliable and objective evidence for the diagnosis, we developed a new algorithm to process the full-field TM surface motion data acquired by scanning laser Doppler vibrometer (SLDV). The frequency bands and areas on the TM highly sensitive to the effusion amount and viscosity in the MEC were identified.Oklahoma Louis Stokes Alliance for Minority Participation ProgramNational Science Foundation (U.S.)Aerospace and Mechanical Engineerin
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