海上风电场高桩承台群桩基础平台的设计研究

针对国内海上风电基础设计没有统一的规范及标准,为提升海上风电基础设计建设的水平,通过对东南沿海某海域海上风电基础的设计进行了有限元计算分析论证,验证了群桩高承台结构设计方案的设计方法和设计参数。分析结果表明该设计的最大应力主要发生在塔筒底座与承台接触部位及钢管桩与承台连接段,应在连接部位加强措施处理;基础竖直位移较小,水平位移相对较大;分界部位应力较集中,刚度不能顺畅过渡,可考虑填充碎石土等方法加强。本研究对海上风电基础设计技术的研究与探索,可为将来制定中国海上风电行业标准提供可靠的依据,对中国未来大批量的海上风电能源的开发有着重要意义。     

东昆仑祁漫塔格地区乌兰乌珠尔早古生代花岗岩锆石U-Pb年代学、地球化学及其地质意义

为确定东昆仑祁漫塔格乌兰乌珠尔地区片麻状黑云母花岗岩和二长花岗岩的形成时代、岩石成因、源区性质和构造背景,对该岩石样品进行了锆石U-Pb年代学、地球化学和锆石Hf同位素研究.结果显示:片麻状黑云母花岗岩加权平均年龄为457.5±2.3 Ma,铝饱和指数A/CNK介于0.98～1.02,属准铝质岩石,Na2O/K2O比值...     

晚上新世以来菲律宾海盆XT4孔黏土矿物特征及其古环境意义

菲律宾海是典型风尘汇聚区,菲律宾海远离吕宋岛的深海沉积物是重建构造尺度亚洲风尘演化历史的良好载体.选取菲律宾海盆XT4孔沉积物开展了黏土矿物研究,并结合前人研究成果,在明确该孔黏土矿物来源的基础上,探讨了晚上新世以来亚洲风尘的演化历史及其可能的影响机制.菲律宾海盆XT4孔黏土矿物以伊利石为主,平均含量为39％,蒙脱石含...     

细菌细胞膜脂记录的西太平洋暖池约4Ma以来沉积物风尘陆源输入变化

西菲律宾海作为西太平洋暖池的一部分,重建其在地质历史时期的热力学变化、陆源输入变化,对于理解西太平洋暖池在全球地质时间尺度上的作用具有重要意义.利用古菌与细菌的细胞膜质甘油二烷基甘油四醚(glycerol dialkyl glycerol tetraethers,GDGTs)对西菲律宾海XT-47孔沉积物的陆源输入及其...     

Quality influencing factors of dispersion curves from short period dense arrays based on a convolutional neural network across the north section of the Xiaojiang fault area

The number of dispersion curves increases significantly when the scale of a short-period dense array increases. Owing to a substantial increase in data volume, it is important to quickly evaluate dispersion curve quality as well as select the available dispersion curve. Accordingly, this study quantitatively evaluated dispersion curve quality by training a convolutional neural network model for ambient noise tomography using a short-period dense array. The model can select high-quality dispersio...     

重组性迁移在主题式教学中的应用研究——以高中地理教学为例

地理主题式教学以地理学科关键能力、地理学科知识、地理思维能力、地理情境设置四个关键维度来架构。利用重组性迁移可以提高学生在新情境中创造性地解决地理问题的水平。高中地理主题式教学应着力整合地理知识的联系,促进地理知识运演结构化的重组性迁移;构建自然地理要素、人文地理要素与区域之间有效的思维主题结构,实现区域性的地理思维模式的重组性迁移;厘清地理要素综合、时空综合、地方综合的逻辑关系,凸显地理综合思维的重组性迁移;建立生活经验与地理专业知识的联系,实现知识能力活性化的重组性迁移;建立跨学科知识的联系,形成整合性的逻辑思维的重组性迁移。     

Purification and Characterization of a Novel Hydrolase That Can Specifically Degrade the Polysaccharide Isolated from Green Seaweed Ulva prolifera

The extracellular polysaccharide hydrolase-producing strain EP-1 was isolated from seawater and identified as Paenibacillus pabuli. Furthermore, a homogeneous extracellular polysaccharide hydrolase from Paenibacillus pabuli EP-1 was purified by combining ion-exchange chromatography and size exclusion chromatography with a purification fold of 90.69 and recovery of 16.23%. Characterization of the purified polysaccharide hydrolase revealed a molecular mass of 38 k Da and optimum activity at 45℃ and pH 6.0. The polysaccharide hydrolase maintained its stability within a wide range of pH(3.0–12.0) and thermal stability when the temperature was below 50℃. The presence of Hg²⁺, Fe²⁺, Mn²⁺, Co²⁺ and SDS notably decreased hydrolase activity, and organic solvents such as formaldehyde, acetone, DMF and acetonitrile completely inhibited hydrolase activity. The purified hydrolase had no activity on agar, carrageenan, gellan gum, sodium alginate, or starch, but effectively hydrolyzed the polysaccharide from Ulva prolifera. The Km and Vmax values of this hydrolase were 43.84 mg m L^-1 and 4.33 mg m L^-1 min^-1, respectively. The sequence analysis with quantitative time-of-flight mass spectrometry indicated that the hydrolase was an endoglucanase.     

Characteristics of Sulfide Removal by Hydrogenovibrio thermophilus Strain TT in Mariculture System

To biologically inhibit the production of highly toxic sulfide in the aquaculture area, one bacterium, designated as Hydrogenovibrio thermophilus strain TT, was isolated from sediment in Jiaozhou Bay, China. The strain was found to be microaerobic mixtrophic, employing both carbon dioxide and organic carbons, e.g. citrate, lactate, glucose, and peptone as carbon sources. When it oxidized the sulfide and thiosulfate, oxygen was the optimal electron acceptor, followed by nitrite and nitrate, which benefited to removal of sulfide under low-oxygen mariculture environment. In addition, the strain TT exhibited remarkable tolerance of sulfide and thiosulfate in seawater, and it was able to oxidize 18.52 mmol L~(-1) S~(2-) in 12 h or 45 mmol L~(-1) S_2O_3~(2-) in 24 h at initial pH 7.0-9.0, 30-40℃. Therefore, this strain showed a quite promising application for biological remediation of sulfide-contaminated mariculture system.     

Rockfall seismic features analysis based on in situ tests:frequency,amplitude, and duration

In the seismic event classification,determining the seismic features of rockfall is significantly important for the automatic classification of seismic events because of the huge amount of raw data recorded by seismic stations in continuous monitoring. At the same time, the rockfall seismic features are still not completely understood.This study concentrates on the rockfall frequency content, amplitude(ground velocity), seismic waveform and duration analysis, of an artificial rockfall test at Torgiovannetto(a former quarry in Central Italy). A total of 90 blocks were released in the test, and their seismic signals and moving trajectories were recorded by four tri-axial seismic stations and four cameras, respectively. In the analysis processing,all the artificial rockfall signal traces were cut separately and the seismic features were extracted individually and automatically. In this study, the relationships between a) frequency content and impacted materials, b) frequency content and the distance between block releasing position and seismic station(source-receiver distance) were discussed. As a result, we found that the frequency content of rockfall focuses on 10-60 Hz and 80-90 Hz within a source-receiver distance of 200 m, and it is well correlated with impacted material and source-receiver distance. To evaluate the difference between earthquake and rockfall, 23 clear earthquake signals recorded in a seven month-long continuous seismic monitoring, carried out with the four seismic stations, were picked out, according to the Italian national earthquakes database(INGV). On these traces we performed the same analysis as in the artificial rockfall traces, and two parameters were defined to separate rockfall events from earthquake noise. The first one, the amplitude ratio, is related to the amplitude variation of rockfall between two stations and is greater than that of earthquakes, because of the higher attenuation occurring for rockfall events, which consists in high frequencies whereas for earthquakes it consists in low frequencies. The other parameter, the shape of waveform of signal trace, showed a significant difference between rockfall and earthquake and that could be a complementary feature to discriminate between both. This analysis of artificial rockfall is a first step helpful to understand the seismic characteristics of rockfall, and useful for rockfall seismic events classification in seismic monitoring of slope.