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1.
筒型基础平台是一种新型海洋平台,它通过在筒腔内产生一个比周围小的压强而自主插入海底,工作期间又具有在筒腔内形成负压来增强抵抗外载荷的能力。本文介绍一种以抗拔能力为设计基准的筒型基础总体尺寸的初步设计6方法,并对方法中的各参数提出了选用原则和取值范围,给出了相应的计算图谱,最后还以两个筒型基础为例演示了方法的使用。  相似文献   

2.
研究了以InAs量子点为有源区的二维GaAs基光子晶体微腔的设计与制作,测试并分析了室温下微腔的光谱特性.观察到了波长约为1137 nm,谱线半高宽度约为1 nm的尖锐低阶谐振模式发光峰.我们比较了不同刻蚀条件下光子晶体微腔的发光谱线,结果表明空气孔洞截面的垂直度是影响光子晶体微腔发光特性的重要因素之一.通过调节干法刻蚀工艺,改变空气孔半径与晶格常数的比率,可以在较大范围内调节谐振模式发光峰位置,达到谐振模式与量子点发光峰调谐的目的.  相似文献   

3.
鳜侧线管结构和行为反应特性及其对捕食习性的适应   总被引:11,自引:2,他引:11  
梁旭方 《海洋与湖沼》1996,27(5):457-462
于1990年8月-1992年4月在汉阳县军江渔场采集鳜标本。运用形态学和行为学实验方法研究其侧线管的形态结构和捕食行为反应特性。结果表明,鳜眶上管、眶下管管腔和神经丘直径最大,部分管道未埋入骨组织中;躯干部侧线管管腔和神经丘直径最小,全部埋入鳞片中;前鳃盖下颌管、眼后管等头部侧线管管腔和神经丘神经介于前二者之间,全部埋入骨组织中。  相似文献   

4.
在超燃冲压发动机扩张型燃烧室中,对凹腔内局部补氧的点火强化方法进行了试验研究。采用高速摄影手段研究了不同的补氧方式对凹腔内火焰分布特征和燃烧强度的影响,并针对并联双凹腔燃烧室构型,研究了在单侧凹腔补氧条件下向异侧凹腔的火焰传播过程。试验结果表明,采用凹腔内补氧的方式能调节凹腔内的燃料浓度分布、改善凹腔内的燃烧过程,控制燃烧放热强度;稳态燃烧情况下,观察到凹腔驻留火焰的两种存在特征,分别表现为:由回流区热量反馈机制作用下的凹腔局部驻留火焰和燃烧室全局压力反馈影响下的凹腔剪切层火焰。只有在单侧凹腔燃烧建立了全局压力反馈的条件下才能实现凹腔火焰的异侧传播。   相似文献   

5.
栉孔扇贝消化管的组织学观察   总被引:5,自引:0,他引:5  
运用石蜡切片法和组织化学方法,对栉孔扇贝的消化管进行了研究,结果表明,整个消化管从腔内到腔外,都由黏膜上皮、黏膜肌层、结缔组织和外膜组成。黏膜上皮层由纤毛柱状细胞和杯状细胞组成,基膜很薄,皮下有一层有肌纤维,结缔组织中有丰富的血腔隙,除直肠的外膜为浆膜外,其余皆为纤维膜。纤毛和黏液在食物的运输中起重要作用。胃和晶杆囊上皮能分泌消化酶。胃上上有较弱的碱性磷酸酶和脂酶活性。胃和晶杆囊上皮及纤毛有酸性磷酸酶活性,晶杆囊上皮的核前细胞质中含铁,各部位不含钙。  相似文献   

6.
中国对虾输精管结构及精子形成   总被引:4,自引:4,他引:4  
采用激光扫描共聚集显微镜及电子显微镜技术,对中国对虾输精管结构及精子的形成过程进行研究。结果表明,中国对虾的输精管可分为近端、中间、远端输精管及壶腹4部分,输精管壁各部分的基本结构相似,但分泌结构的结构有较大的差别。输精管自中间膨大部开始,管腔逐渐被一隔膜分为大小不等的两部分,较大的腔内充满了很多精子,输精管较小的腔内充满胶体状物质,中国对虾精子细胞在精巢内产生,在两条输精管内逐渐发育,经过细胞质的分化并与精子外部进行物质的交换,形成顶体、亚顶体及棘突。核的变化则经历了染色质的解凝和核膜的消失,最后形成成熟的精子。  相似文献   

7.
褐牙鲆鳃氯细胞的超微结构研究   总被引:4,自引:0,他引:4  
利用透射电镜技术,研究了褐牙鲆(Paralichthys olrvaceus)鳃氯细胞的超微结构特征。研究表明,褐牙鲆鳃氯细胞主要分布于鳃小叶基部,具有微细小管系统和分泌腔。有丰富的线粒体,细胞核基位。根据氯细胞结构的不同,将其分为4种类型:I型氯细胞、Ⅱ型氯细胞、Ⅲ型氯细胞和Ⅳ型氯细胞。I型氯细胞胞体较大,细胞基质密度较低。微细小管系统发达呈细管状;Ⅱ型氯细胞外形不规则。胞体较大,细胞基质密度较高,微细小管系统主要呈粗网状;Ⅲ型氯细胞外形不规则,细胞基质具有很高的电子密度,微细小管系统不发达,胞内存在大量线粒体,分泌腔小;Ⅳ型氯细胞为扁平状,细胞体积较小,具有较大的分泌腔,但微细小管系统不发达。褐牙鲆鳃氯细胞系统是主要的渗透压调节系统。  相似文献   

8.
宋有建  胡明列  谢辰  柴路  王清月 《海洋学报》2010,32(10):7105-7110
设计并搭建了一种支持百纳焦耳量级的单脉冲能量输出的锁模光纤激光器.激光器基于σ型腔结构,采用掺Yb偏振型大模场面积光子晶体光纤作为增益介质,利用半导体可饱和吸收镜实现自启动锁模.激光器内没有色散补偿机理,使其工作在全正色散锁模状态.通过在谐振腔内引入多通长腔使激光器的重复频率降低至11.1 MHz,直接获得了平均功率为1.08 W,单脉冲能量为 97 nJ,脉冲宽度为4.17 ps的稳定锁模脉冲输出,经腔外色散补偿,脉冲宽度压缩至740 fs.  相似文献   

9.
XBT是可投弃式温深剖面测量仪的简称,用以测量海水不同深度的温度。为了研究XBT探头内部光纤传感器的合理布放位置,以尽可能减小温度与压力测量的误差,针对探头在水中的主要运动状态,运用CFX软件做瞬态温度响应模拟,包括阶跃温度响应和线性温度响应;然后对不同运动速度的XBT探头做稳态数值模拟,着重分析了其导流腔内水流速度与压力分布。模拟结果表明,线性响应引起的温度测量误差要小于阶跃响应,温度传感器宜放在导流腔中靠前的位置,同时导流腔后端存在水流静压为0的位置,适合压力传感器的布放。本文针对光纤XBT探头所做的流体仿真,为内部温度、压力传感器的布置提供了理论指导,对于同类传感器的设计也具有一定的参考价值。  相似文献   

10.
深海探测溶解无机碳含量异常,可以为寻找热液口提供一个很好的证据。本文设计的基于自制的聚二甲基硅氧烷胶与Zn-Al型水滑石复合膜为离子载体的溶解无机碳探测电极属于电势型电极,适用于对深海中溶解无机碳的测量,具有体积微小、便于与pH、盐度、温度、氧化还原电位等多种传感器集成在同一探头腔内,实施在线探测等优点。实验室条件下,将该溶解无机碳探测电极与银/氯化银参比电极分别接在Keithley 6517A高阻抗电位计输入端进行测试,测试结果表明:该电极对不同浓度的碳酸氢钠溶液具有良好的响应信号,响应时间大约在30s—1 min,检测限在10-1—10-4mol?L–1。  相似文献   

11.
The high-speed water entry process of an autonomous underwater vehicle (AUV) has a strong impact nonlinearity, and a cavity formed by air and water will often be generated as part of the entry process. The shape of the water-entry cavity plays an important role in the load characteristics and stability of the water-entry trajectory. In this paper, a numerical model for describing the cavity and impact load characteristics of a high-speed water-entry AUV is established. The simulation results such as cavity shape and impact load are compared with experimental data. The good agreement between the numerical results and those of the experiments reveals the accuracy and capability of the numerical algorithm. Subsequently, the arbitrary Lagrange-Euler (ALE) numerical algorithm is used to simulate and analyse the variation laws of the cavity characteristics and impact loads with different head shapes, water-entry velocities, water-entry angles and angles of attack. The results obtained in this study can provide a good reference for the trajectory control and structural design of the AUV.  相似文献   

12.
In this paper, the movements of the analytical models of complete underwater tracked vehicle (UTV) and cutter bar (CB) tool systems on a surface as well as their movements up and down a slope in the up-cutting mode operation are fully studied and analyzed. First, the mathematical expression of the mechanics, for which the forces, moments, and energy from the CB to the UTV are analyzed, is related. Next, analyses on the systemic parameters and their sensitivity are conducted to observe the variations of the operational and geometric parameters, as well as the cutter-tool and material-condition effects on the force, moment, and power components. Also, a design process composed of seven typical steps is proposed as the reference of a trencher-machine design. The important design parameters of the trenching machine such as the length of the CB, the nose radius of the CB, and the height of the pivot point are designed according to the proposed design process; furthermore, these parameters are used for the estimation of the slope-angle range when the trencher system is working on the slope. To demonstrate the application of derived equations to practical problems of the machine design, a number of numerical simulations are performed. Through the numerical simulations, the important parameters of the system such as the tangential force, Ft, the tractive thrust, H, the normal reaction, V, the cutting moment, Mc, the maximum carrier weight, W, and the available power are analyzed. From these, as a reference data for the designing of a trencher machine, the previous design of the system can be improved.  相似文献   

13.
湍流剖面仪系统动力学分析与实验研究   总被引:2,自引:0,他引:2  
文章开发了采集海洋湍流数据的一种新型湍流剖面仪。应用动力学方法分析了系统运动特性,并设计开发了原理样机,包括:微尺度流信号放大处理电路,并扩展了FLA SH存储器(K 9f2808U 0C)保存测量结果,及RS232传输协议的数据通信电路设计。此系统可获得海洋垂直剖面2 mm尺度的剪切流速度数据。湖试实验结果表明此湍流剖面测量仪性能良好,可以满足微结构流测量要求。  相似文献   

14.
中国开辟区多金属结核粒径分析及其意义   总被引:5,自引:5,他引:0  
为了便于多金属结核的开采、结核分布规律的探讨和矿藏储量计算,对DY85-4航次所取得的多金属结核抽样样品进行了逐个三轴粒径测量和称量工作,并进行了统计分析和分形研究,得到了多金属结核的粒径统计分布规律。从而为集矿机的设计提供了科学依据。  相似文献   

15.
Bottom ventilated cavitation has been proven as a very effective drag reduction technology for river ships and planning boats. The ability of this technology to withstand the sea wave impact usual for seagoing ships depends on the ship bottom shape and could be enhanced by some active flow control devices. Therefore, there is the need in numerical tools to estimate the effects of bottom changes and to design such devices. The fundamentals of active flow control for the ship bottom ventilated cavitation are considered here on the basis of a special model of cavitating flows. This model takes into account the air compressibility in the cavity, as well as the multi-frequency nature of the incoming flow in wavy seas and of the cavity response on perturbations by incoming flow. The numerical method corresponding to this model was developed and widely manifested with an example of a ship model tested in a towing tank at Froude numbers between 0.4 and 0.7.The impact of waves in head seas and following seas on cavities has been studied in the range of wavelengths from 0.45 to 1.2 of the model (or ship) length. An oscillating cavitator-spoiler was considered as the flow controlling devices in this study. The oscillation magnitude and the phase shift between cavitator oscillation and the incoming waves have been varied to determine the best flow control parameters. The main results of the provided computational analysis include oscillations of cavity surface, of the pressure in cavity and of the moment of hydrodynamic load on the cavitator. The major part of computations has been carried out for the flap oscillating at the frequency coinciding with the wave frequency, but the effect of a frequency shift is also analyzed.  相似文献   

16.
The objective of this paper is to theoretically demonstrate how the operational frequency affects the efficiency of a low-speed generator. Due to the varying nature of underwater currents, the voltage from a current power converter has to be rectified first and then digitally reconverted into a stable alternating current. When designing a direct drive generator for water current power conversion, the operational frequency is, thus, a free design parameter and not a fixed value determined by the grid. Finite element method was used to determine the efficiency and weight. A higher frequency means larger frequency-dependent losses, but also a lighter machine. Even at the highest frequency in this study, the frequency-dependent losses were not high enough to overcome the gain of a lighter machine. If a large generator diameter can be allowed, the water current power converter should be designed with as high operational frequency as possible.  相似文献   

17.
多金属结核粒径分形特征初步研究   总被引:3,自引:0,他引:3  
通过对东太平洋中国开辟区东、西两区的多金属结核进行粒径分析,发现其粒径分布有分形特征。无缆取样结核粒径分形有着上、下限,虽然在小粒径上没有分形关系,但却存在着另一种确定的线性关系。说明东、西区结核在粒径、重量等分布上有着客观的一致性。通过分形分析得到了结核空间分布、粒径和重量分布的线性方程,对多金属结核矿藏储量和集矿机设计具有一定的意义。  相似文献   

18.
超大直径单桩基础在应用过程中,存在钢管桩沉桩的选锤、防溜桩等关键问题.为解决以上问题,研究超大直径单桩的竖向抗压承载力是有必要的.分别利用《码头结构设计规范》规定的设计做法、圆孔扩张理论法、UWA-05方法、GRLWEAP模型方法对超大直径钢管桩的竖向抗压承载力进行了分析计算并结合工程实例进行比较,发现现行规范规定的钢管桩承载力计算公式对于超大直径钢管桩承载力的估计偏于保守,高应变检测法对于超大直径单桩基础承载力的评估同样偏于保守.  相似文献   

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