Experimental Study and Fatigue Analysis of Vortex-Induced Vibration of Umbilical Cable Considering Internal Friction

In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses,the experimental study on VIV of bond umbilical cable(BUC)and un-bond umbilical cable(UBUC)was carried out in an experimental tank.A current generator in the laboratory simulated the uniform current,and the current velocities were observed in real time by using a Doppler Velocimeter.In addition,different sizes of top tension were applied to the umbilical cable model.The VIV responses of the umbilical cable model were measured by using Fiber Bragg grating(FBG)strain sensors.The displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition method.In this paper,the traveling wave characteristics,the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are studied.The experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of VIV.The UBUC appears the traveling wave sooner than BUC,but its standing wave characteristics are more obvious than those of BUC at high velocities.Compared with BUC,the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner,but has narrower bandwidth in the"lock-in"state.The level of fatigue damage of BUC was approximately the same as that of UBUC.

Establishment and application of an accurate identification method for fragrant soybeans

In order to screen the aroma characteristics of soybean,a new method was established which can quickly quantify the content of 2-acetyl-1pyrroline(2-AP),an important compound related to soybean aroma,using gas chromatography-mass spectrometry(GC-MS).Based on peak profile,total peak area and retention time as test indexes,an accurate identification method for fragrant soybeans was established.The optimum parameters of the protocol consisted of column temperature70℃,sample injector temperature 180℃,optimum extraction alcohol content 1 m L,Na Cl content 0.1 g,ultrasonication time10 min,and extraction time 1 h,which were established by using the orthogonal test of single factors and three factors with four levels(L_9(3)^4).2-AP content of leaves had significant correlations with seeds,which were easier to measure.The protocol was simple and easy to carry out,consumed only small amounts of reagents,and provided accurate and reliable results with good reproducibility.A total of 101 soybean genotypes from different geographical sources were analyzed using this protocol.The results showed that the average content of 2-AP was 0.29 mg L^(–1),ranging from 0.094 to 1.816 mg L^(–1),and the genetic diversity index was 0.54.Among all genotypes-tested,they were classified into three grades,including seven elite genotypes identified as"grade one fragrant soybeans",which were Zhonglong 608,Heinong 88,Ha13-2958,Hongmiandou,Heinong 82,Huangmaodou,and Jiyu 21.These results provide both an identification technique and several elite aroma genotypes for gene discovery and good quality breeding in soybean.

Screening of Optimal Differentiation Medium to Lonicera edulis

An excellent Lonicera edulis strain, L1-8 that was bred by Northeast Institute of Geography and Agro-ecology, Chinese Academy of Sciences, was used as material in this research. The axillary buds of its dormant branches were used as explants. A fourfactor and four-level orthogonal test was designed in order to choose the best differentiation medium for providing the technical support of Lonicera edulis micropropagation. The results showed that the culture medium and concentration of 6-BA were the main factors, and the best differentiation condition was MS culture medium containing 2.0 mg · L-1 6-BA, 0.3 mg · L-1 IBA and 1.5 mg · L-1 GA3.

体积积分法在油气藏评价中的应用——以伊拉克哈法亚油田为例

油气藏评价通常采用容积法,储集层体积是由含油气面积与地层有效厚度直接相乘来获得,这忽视了圈闭构造形态变化的影响。现提出采用体积积分法计算储集层体积并对油气藏进行评价,目的是使用更接近真实值的储集层体积,获得更准确的油气资源量。通过对伊拉克哈法亚油田上白垩统Tanuma组油藏深入研究,结合地震资料和井资料,建立了基于储集层构造图的体积积分法模型。同时,将容积法中含油气面积和有效厚度两个参数分别取大、中、小值,形成了9种组合结果。通过对比发现,体积积分法结果和容积法评价结果中值或平均值非常相近。本研究认为,体积积分法计算结果能够反映圈闭构造形态的变化,与容积法相比确定性更大;而容积法取值更灵活,能更好地反映油气藏资源量范围。

大豆BADH基因的生物信息学、多样性及功能分析

为研究大豆中甜菜碱醛脱氢酶(BADH)在大豆中的分子机理及生物多样性,通过基因序列同源比对搜索到两个与水稻同源的大豆BADH基因,利用Phytozome、Netphosk 3.0 Server等网站及数据库对其进行生物信息学分析,结合已有的重测序数据分析1 598份大豆种质中BADH基因序列的多态性,并测定突变体的2AP含量。结果表明:大豆中有两个与水稻BADH基因同源性较高的基因序列Gm06g186300和Gm 05g0330550,基因全长分别为3 959和6 008 bp,编码蛋白均属于稳定蛋白质,二者同源性高达90%。两个蛋白的氨基酸数目、分子量和等电点等非常相似;亲水性和磷酸化位点分布较一致,均无跨膜结构域,在细胞核出现的可能性最大,且二者进化关系极其相近;α螺旋和无规则卷曲是两者的主要成分,BADH1和BADH2有1个共同的结构域Pfam-Aldedh,且分布大致相同。对1 598份大豆种质BADH基因序列突变位点进行分析,有29份材料BADH2基因发生6个碱基序列突变导致了移码突变,这种突变可能与大豆的芳香性表型有关。对BADH1及BADH2在大豆不同部位的基因表达量分析发现各部位的表达量相差很大,均以根部表达量最高,可能与根部较高的抗旱能力有关。

振荡流下悬链线式立管涡激振动特性研究

本文应用改进的尾流振子模型对振荡流下悬链线式立管的涡激振动特性进行了研究。首先基于向量式有限元建立了悬链线式立管振动控制方程,利用独立性原理和改进的尾流振子模型模拟时变的涡激升力,然后采用中央差分法求解立管的涡激振动响应。利用相应的试验结果验证了本文模型的有效性。最后,对振荡流下悬链线式立管涡激振动响应特性进行了分析。研究结果表明:振荡流下悬链线式立管响应幅值出现“振幅调制”现象,大KC(Keulegan-Carpenter)数下,进一步出现典型的“间歇涡激振动”现象;KC数对质点振动相图形状以及流固能量传递有显著影响;振荡流下立管响应峰值随流速呈“多峰”现象,KC=20时多峰现象更为明显;在小KC数范围内,较小的KC数会激励立管产生较大的涡激振动位移。

预张力对两种脐带缆涡激振动影响的试验研究

本文应用模型试验的方法,研究了预张力对粘结和非粘结两种脐带缆涡激振动响应特性的影响规律。基于模态叠加法,将测得的应变数据转变为结构的位移响应;对比分析了各级预张力下两种脐带缆模型的位移响应、结构振动频率、锁振影响区域、模态占比等参数。结果表明:两种脐带缆模型锁振频率随着预张力的增加逐渐变大,非粘结锁振比粘结工况提前;远离锁振区域时,外流速变化对振幅的影响占主导地位,锁振区域附近,预张力变化对振幅的影响逐渐变大;随着流速增加,预张力变化对脐带缆横向振动模态占比影响逐渐变大;预张力较小时,粘结脐带缆振动模态随外流速转换相比于非粘结脐带缆滞后较多,预张力变大后,滞后程度减小。