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排序方式: 共有480条查询结果,搜索用时 31 毫秒
91.
解析了建筑外环境空间大小的含义,以及"以小见大"空间设计手法。从静态观察和动态体验过程以及建筑外部环境场的尺度设计3个角度,探讨了建筑外部环境空间如何由"小"来得到美而丰富的空间体验的方法与途径。旨在尊重自然、顺应自然、尊重历史的前提下,精心设计建筑环境景观空间。 相似文献
92.
93.
This study investigated the effects of ultraviolet-C (UV-C) light applied to both sides of mushrooms on microbial loads and product quality during storage for 21 d at 4 °C. Microflora populations, color, antioxidant activity, total phenolics, and ascorbic acid were measured at 1, 7, 14 and 21 d of storage. Additionally, the inactivation of Escherichia coli O157:H7 by UV-C was determined. Results showed that UV-C doses of 0.45-3.15 kJ m−2 resulted in 0.67-1.13 log CFU g−1 reduction of E. coli O157:H7 inoculated on mushroom cap surfaces. UV-C radiation also reduced total aerobic plate counts by 0.63-0.89 log CFU g−1 on the surface of mushrooms. Although mushrooms treated with UV-C had more severe browning with increasing dosage after initial treatment, the control mushrooms also browned as indicted by lower L* and higher a* values after 21 d of storage at 4 °C. In addition, the UV-C treatments apparently inhibited lesion development on the mushroom surface. During the first 7 d, irradiated mushrooms had lower antioxidant activity, total phenolics, and ascorbic acid content compared to non-radiated samples. However, irradiated mushrooms reached similar amounts of these nutrients as the control after 14 d of storage at 4 °C. In summary, UV-C radiation could potentially be used for sanitizing fresh button mushrooms and extending shelf-life. 相似文献
94.
研究热处理对新鲜椰子水过氧化物酶(Peroxidase,简称POD)和多酚氧化酶(Polyphenol oxidase,简称PPO)相对酶活力和色泽变化影响,探讨椰子水酶活力与其色泽的相关性。结果表明,随着热处理温度升高或时间的延长,椰子水的POD和PPO相对酶活力均随之降低,其中90℃和95℃热处理4 min后,可分别使POD和PPO的活力降低90%以上。随着热处理温度的升高,椰子水的色泽随之加深;椰子水的PPO和POD相对酶活力与色泽加深程度呈负相关关系,且具有一定的显著性。该结果可为后续研究椰子水色变控制技术提供一定的理论基础。 相似文献
95.
Doppler ultrasound is an emerging technology that has the potential to increase the diagnostic, monitoring, and predictive capabilities of equine theriogenologists and researchers. The technology is based on Doppler-shift frequencies, wherein the ultrasound frequency of echoes from moving red cells is increased or decreased as the cells move toward or away from the transducer. In spectral mode, the blood flow in a specific vessel can be assessed by placing a sample-gate cursor on the image of the lumen of the vessel. In addition, an angle cursor can be used to represent the angle of intersection of the ultrasound beams with the direction of blood flow (Doppler angle). The Doppler-shift frequency and the Doppler angle are used by the instrument for computing blood velocity. The focused results from placement of a sample gate in an artery are displayed by a spectrum that represents the changing velocities over time in association with the pulses of cardiac cycles. Peak systolic, end diastolic, and time-averaged maximum velocities are computed and shown for a selected cardiac cycle. Doppler indices (resistance index, RI; pulsatility index, PI) are ratios that are computed from various points on the spectrum. The indices are relatable to the hemodynamics of the tissue supplied by the artery. Increasing RI or PI values indicate increasing resistance and decreasing perfusion of the distal tissues. In color-flow mode, Doppler-shift frequencies are obtained from areas delineated by the operator on the B-mode image and are transformed and expressed as color-coded spots representing areas of blood flow. Vascular perfusion of a structure can be quantitated by the number of colored pixels in an image or can be estimated subjectively by the extent of the colored spots. The Doppler technology has the potential for providing information on the status and future success of a structure. However, realization of the expected potential will depend on future experience and research. 相似文献
96.
土壤学始于对土壤剖面及其形态特征的观察,剖面发生层的划分与发生层边界特征的描述是土壤调查的基础。实地划分发生层需要丰富的土壤学实践经验,存在主观和缺乏统一划分标准的问题。以紫色土剖面图像为研究对象,采用K-means聚类和图像分割技术,结合图像的颜色特征(CIE Lab色彩空间)和纹理特征(Entropy)识别紫色土剖面发生层边界,并与实地划分的结果进行比较。结果表明:(1)CIE Lab色彩空间的a、b通道和Entropy纹理特征,可以划分出供试剖面的主要发生层(A、B、C)和基岩(R);(2)聚类识别的发生层数量和发生层深度与实地识别的结果基本一致;除Z2剖面的C层和Z6剖面的Ap层聚类识别与实地识别的发生层下边界深度相差较大(分别为13 cm和8 cm)外,其余发生层下边界深度相差均在3 cm以内;(3)聚类识别的发生层边界形状更为不规则,明显度更为模糊。K-means聚类和图像分割技术实现了紫色土剖面发生层边界的客观识别,可为土壤剖面智能辨识系统的开发提供科学参考。 相似文献
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99.
以鲜食黄桃金陵黄露为试材,研究不同透光率的纸袋对果实色泽和品质的影响。结果显示,套袋处理增加了金陵黄露果皮的L值和b值,降低了a值,随着透光率的减少,果皮呈现深红、鲜红、黄红相间、黄色。其中1-KW(透光率25%)、1-KK(透光率20%)、1-LP (透光率0)3个套袋处理后果皮的L、a、b值与对照(不套袋)均达到显著性差异水平。套袋处理后降低了金陵黄露果实可溶性固形物、可溶性糖、总酸和Vc含量,其中1-LP处理后四个指标分别为10.3、9.42、0.45和8.77mg/100g,与对照达到显著性差异。结果表明,黄桃果实色泽与纸袋的透光率紧密相关,为定向生产不同色泽的黄桃提供了思路,同时建议果实套袋后相关加强肥水管理和进行采前除袋。 相似文献
100.
Colorimetry of wood specimens from French Guiana 总被引:1,自引:0,他引:1
Yoshihiko Nishino Gérard Janin Bernard Chanson Pierre Détienne Joseph Gril Bernard Thibaut 《Journal of Wood Science》1998,44(1):3-8
The color of 97 species of wood specimens from French Guiana was measured on their radial and tangential surfaces with a colorimeter. We obtained the tristimulus values of X, Y, and Z of the 10° standard observer under the illuminant of D
65, and the values of the CIELAB color system, L
*, a*, b*, C*, and h. When the lightness index (L
*) was <54, b
*, C
*, and h showed positive correlations against L
*. When L
* was >54, a
* and C
* showed negative correlations against L
*. These results imply that wood color should be discussed by separating wood specimens into the high and low-lightness groups. A good positive correlation was found between the L
* and h throughout the whole range of L
*. It is thought that the value of h can be an important index, as can L
*, for comparing of wood color because h shows a simple relation with L
*. 相似文献