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Profiled lightly-doped drain (PLDD) MOSFETs are fabricated. Their characteristics are compared with those of other device structures. The current driving capability and transconductance of LDD devices can be increased with PLDD structures. 相似文献
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A SISO self-tuning controller with a Smith-predictor type of time delay compensator (STC-TDC) is proposed to handle open-loop stable processes with unknown or varying time delays. Two numerical examples comparing PI control, the standard STC of Clarke and Gawthrop, the self-tuning Dahlin algorithm of Vogel and Edgar, and the STC-TDC show that the new approach performs best for both set-point and load changes when process time delay changes occur. A third example shows that the STC-TDC matches the extended stability characteristics of the alternative approach due to Kurz and Goedecke but is computationally much simpler. 相似文献
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利用数值分析,研究影响黏土层中基坑挡土墙最大变形量的参数,根据参数研究的结果,利用复回归分析,给出挡土墙最大变形量的简易评估法。然后利用简易评估法,预测4个台北基坑案例的连续墙最大变形量,并与现场监测结果进行比较。结果显示:预测的最大变形量在0.85~1.15倍监测值范围内。因此,本文给出的简易评估法,可为初步预测、设计及最后检核设计成果提供参考。 相似文献
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CHANGES OF POLYAMINE CONTENT IN CHINESE CABBAGE DURING STORAGE IN AIR OR LOW OXYGEN ATMOSPHERE 总被引:2,自引:0,他引:2
CHIEN YI WANG 《Journal of food quality》1988,11(4):289-302
Endogenous levels of polyamines, including putrescine, spermidine, and spermine, were determined in the outer laminae, outer midribs, inner laminae, and inner midribs of Chinese cabbage (Brassica campestris L. Pekinensis group) during storage at 0°C in air or in 1% O2 atmosphere. In the outer laminae where tissues were more mature, polyamines declined linearly with storage at 0°C. The content declined more slowly in low oxygen-stored samples than in air-stored samples. In the inner laminae where tissues were still meristematic, polyamines in both air- and low oxygen-stored samples showed a quadratic response and increased during the first 6 weeks of storage. Thereafter, the level of polyamines decreased under both treatments, but a higher level was maintained in the low oxygen-stored samples. 相似文献
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EFFECT OF MOIST HOT AIR TREATMENT ON SOME POSTHARVEST QUALITY ATTRIBUTES OF STRAWBERRIES 总被引:8,自引:0,他引:8
CHIEN Y. WANG 《Journal of food quality》2000,23(1):51-59
‘Northeaster’ strawberries were heated with moist hot air at 36, 39, 42, 45, 50 and 55C for 0, 20,40, 60, 80 or 100 min. Fruit were injured when exposed to temperatures 50C or higher, or durations of 60 min or longer at 45C. Treatment at 45C for 40 min or at 42C for 60–100 min resulted in the least decay incidence after 5 days at 0C, 3 days at 10C, and 1 day at 20C. Heated strawberries in general had lower titratable acidity, higher soluble solids content and higher levels of fructose, glucose, and sucrose than nonheated samples. Heated fruit also had a higher soluble solids/acid ratio, but lower citric acid and malic acid content. The lightness measurements, L*, and chroma values, C*, were decreased by moist hot air treatment and the fruit were duller and less bright in appearance after heat treatment. Strawberries heated at 39C or lower temperatures had no discernable differences from nontreated fruit in quality attributes measured. However, fruit treated with 45C for 40 min or 42C for 60–100 min maintained better postharvest quality than other treatments. 相似文献
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METHYL JASMONATE IMPROVES QUALITY OF STORED ZUCCHINI SQUASH 总被引:2,自引:0,他引:2
Freshly harvested zucchini squash (Cucurbita pepo L., cv. Elite) were pressure infiltrated (82. 7 kPa for 3 min) with an aqueous suspension solution of 0.1 mM methyl jasmonate, while control fruit were similarly infiltrated with distilled water. All fruit were then stored at a chilling temperature of 5C. Chilling injury symptoms developed in the control fruit after 4 days of storage. However, the onset of chilling injury was significantly delayed by methyl jasmonate treatment. The methyl jasmonate treatment not only retarded the development of chilling symptoms in zucchini squash, but also maintained higher levels of carbohydrates and organic acids during storage compared with the controls. Fructose and glucose were major carbohydrates, and malic acid was the predominant organic acid in zucchini squash. Methyl jasmonate reduced the losses of these sugars and organic acids, and thus helped maintain better internal quality of zucchini squash during cold storage. 相似文献