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侵蚀细沟水力学特性及细沟侵蚀与形态特征的试验研究 被引量:68
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作者 雷廷武 M.A.Nearing 《水利学报》 EI CSCD 北大核心 2000年第11期49-54,共6页
本文进行了一系列水槽试验 ,研究不同长度的侵蚀细沟在坡度及入流量影响下的浅水水流水力学特性、侵蚀量及细沟的形态特征 .所采用的土壤材料为砂壤土 ,试验使用四种入流流量 ,四种坡度 ,四种细沟长度 .记录水流速度、沟宽及径流中的泥... 本文进行了一系列水槽试验 ,研究不同长度的侵蚀细沟在坡度及入流量影响下的浅水水流水力学特性、侵蚀量及细沟的形态特征 .所采用的土壤材料为砂壤土 ,试验使用四种入流流量 ,四种坡度 ,四种细沟长度 .记录水流速度、沟宽及径流中的泥沙含量 ,并用多元回归方法分析了它们与坡度、入流量或它们的交互项之间的关系 .提出了一种数学模型来描述试验中沟宽的周期性形态变化 .提出了通过试验得出的不同细沟长度的产沙量来确定水流输沙能力的方法 ,并得出出测定输沙能力的采样长度为 2~ 4m 。 展开更多
关键词 水槽试验 周期性形态 细沟侵蚀 水力学
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老年高血压患者联合使用缬沙坦和非洛地平降压治疗的时间治疗学研究 被引量:18
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作者 叶毅敏 叶志荣 苏敬荣 《中国循证心血管医学杂志》 2016年第8期916-918,共3页
目的探讨在降压药物种类和数量相同的情况下,通过改变缬沙坦的服药时间对老年高血压患者血压周期性变化的影响。方法拟选择住院的非杓形老年高血压患者167例。随机、单盲的方法将入选患者随机分为2组,服用缬沙坦80 mg和非洛地平5 mg,1/... 目的探讨在降压药物种类和数量相同的情况下,通过改变缬沙坦的服药时间对老年高血压患者血压周期性变化的影响。方法拟选择住院的非杓形老年高血压患者167例。随机、单盲的方法将入选患者随机分为2组,服用缬沙坦80 mg和非洛地平5 mg,1/日,1次1片。A组(n=82)服药时间选择在早7时,即两种降压药物均于清晨服用;而B组(n=85)服用缬沙坦的时间为晚7时,即非洛地平于清晨服用,缬沙坦夜间服用。治疗随访8周后复查24小时动态血压监测(ABPM)。结果 15例患者因失访或未能按要求服药而被退出,A组共74例、B组共78例患者完成治疗。B组患者夜间平均收缩压、舒张压及24 h平均收缩压、舒张压的降低程度均显著高于A组(P<0.01及P<0.05);夜间血压下降率的增加显著高于A组(P<0.01),非杓形血压的比例下降程度亦显著高于A组(P<0.01)。结论对于血压周期性形态为非杓形患者,将缬沙坦放在夜间服用可改善患者的夜间血压下降率,有助于纠正患者的血压节律。 展开更多
关键词 老年高血压 缬沙坦 时间治疗学 动态血压监测 血压周期性形态
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REDUCING PERIODIC NOISE USING SOFT MORPHOLOGY FILTER 被引量:2
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作者 JiZhen MingZhong +1 位作者 LiQi WuQinghua 《Journal of Electronics(China)》 2004年第2期159-162,共4页
A novel spatial domain method--soft morphology filter is presented for reducing the periodic noise in image processing. The simulation results are presented to demonstrate the effectiveness of the method in comparison... A novel spatial domain method--soft morphology filter is presented for reducing the periodic noise in image processing. The simulation results are presented to demonstrate the effectiveness of the method in comparison with a frequency domain method and other spatial domain filters. 展开更多
关键词 Soft morphology Noise reduction Periodic noise
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Effects of temperature fluctuations on cuttlebone formation of cuttlefish Sepia esculenta 被引量:2
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作者 雷舒涵 张秀梅 +1 位作者 刘松林 陈四清 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第4期547-553,共7页
The morphological characteristics and the cuttlebone formation of Sepia esculenta exposed to different water temperature fluctuations were investigated under laboratory conditions. Temperature fluctuation cycles (15 ... The morphological characteristics and the cuttlebone formation of Sepia esculenta exposed to different water temperature fluctuations were investigated under laboratory conditions. Temperature fluctuation cycles (15 cycles, 60 d in total) consisted of the following three regimes of 4 d duration: keeping water temperature in 26℃ for 3 d (Group A), 2 d (Group B), 0 d (Group C, control); then keeping water temperature in 16℃ for the next 1, 2, 4 d. No significant difference in the survival rate was observed between the control and temperature fluctuation groups (P〉0.05). Lamellar depositions in a temperature fluctuation cycle were 2.45±0.02 for Group A, 2.00±0.02 for Group B, and 1.78±0.02 for Group C (P〈0.05). The relationship between age and number of lamellas in the cuttlebone of S. esculenta under each water temperature fluctuation could be described as the linear model and the number of lamellas in the cuttlebone did not correspond to actual age. Group A had the highest cuttlebone growth index (CGI), the lowest locular index (LI), and inter-streak distances comparing with those of control group. However, the number of lamellas and LI or CGI showed a quadratic relationship for each temperature fluctuation group. In addition, temperature fluctuations caused the breakage of cuttlebone dark rings, which was considered a thermal mark. The position of the breakage in the dark rings was random. This thermal mark can be used as supplementary information for marking and releasing techniques. 展开更多
关键词 Sepia esculenta cuttlebone formation temperature fluctuations cuttlebone growth index locular index inter-streak distances
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