天津潮间带春季贝类资源调查

为研究天津潮间带贝类资源的分布特征,2017年5月,作者对天津滩涂开展贝类资源调查。共采集贝类30种,分属2纲、4亚纲、10目、19科,在汉沽鲤鱼门、大港减河口、大港滨海湿地分别采集贝类20种、19种、19种;高潮区、中潮区、低潮区分别采集贝类11种、22种、10种;H'值大小顺序为鲤鱼门滨海湿地减河口,中潮区高潮区低潮区;经济贝类主要分布于中潮区,鲤鱼门与减河口滩涂的优势经济种均为菲律宾蛤仔(Ruditapes philippinarum),生物量分别为562.8、828.5 g/m~2,滨海湿地的优势经济种为四角蛤蜊(Mactra veneriformis),生物量为1 403.8 g/m~2。对比2013年,大港减河口滩涂的贝类种数及生物量均升高,鲤鱼门滩涂的贝类种数增加,滨海湿地滩涂的贝类资源为首次报道。     

极区冰基拖曳式海洋剖面浮标系统低功耗设计与实现

针对极区冰基拖曳式海洋剖面浮标长期稳定获取极区水文和气象数据的工作需求,进行了浮标系统的低功耗方案设计。该方案基于超低功耗51系列微处理器,根据最低功耗工作模式与最短工作时间原则,采用高效的电源管理机制对浮标系统各个部分的能量消耗进行合理的分配与管理,并应用了Argos卫星通讯模块ARGOS-3 PMT-RFM的BPSK调制低速数据传输模式,可有效降低浮标系统的整体能耗。该浮标在北极冰站上长达1年的运行情况表明该系统工作稳定,所采用的低功耗能量管理方案实现了浮标系统长期连续观测的需求。该浮标的成功试验和推广应用有助于极地研究人员更准确地分析海冰变化过程。     

基于熵权的海岛地区城市生态系统健康动态评价研究——以舟山群岛新区为例

文章将舟山群岛新区作为研究对象,以结构、功能、协调这3个基准点为视角,构建舟山群岛新区城市生态系统健康的评价指标体系;运用熵权法进行客观赋权,探讨海岛地区城市生态系统健康的主要影响因素;分析系统各主要因素间彼此的联系和相互关系,评价舟山城市生态系统健康动态,以便进一步提高舟山群岛新区城市生态系统健康水平,优化经济结构,为加强海岛地区生态与环境管理,促进海岛地区经济发展提供决策依据。研究结果表明:近年来,舟山群岛新区城市生态系统健康程度以稳中有升的趋势在不断提高;结构指数有小幅波动,功能指数波动显著,改善明显,其中,城市环境是造成结构指数波动的主要原因。城市文明率较低和可持续性持续走低是城市协调度的主要限制因素。由此,优化资源配置、改善经济结构、持续减排、提升城市环境是确保舟山群岛新区城市生态系统健康水平的关键。     

东太平洋CC区西区表层沉积物黏土矿物和地球化学特征

本文以太平洋CC区西区12个表层沉积物样品作为研究对象,对其粒度、化学组分和矿物成分进行分析,讨论其沉积环境和物质来源。研究区地处深海,主要以深海黏土和硅钙质黏土为主,含有少量的硅质黏土、黏土质硅质软泥和黏土质钙质软泥。黏土矿物成分主要是蒙皂石和伊利石,含有部分的高岭石和绿泥石。黏土矿物组成表明,区内沉积物主要是陆源,由高空气流携带而来,南极底流和热液活动对其物源的来源有一定影响。沉积物地球化学特征也表明,物源以陆源为主,稀土元素分布曲线和北太平洋表层海水稀土曲线类似,且表现出强的Ce亏损,表明生物活动导致的生物沉降对表层沉积物也有一定的影响。     

基于倒置声学基阵的INSUSBL组合导航算法研究

文中关注水下潜航器导航定位时,电磁波传播途径中能量衰减、惯导系统长航时积累误差以及提高水下潜航器定位精度等问题。基于倒置的超短基线声学基阵,分析声波往返传播时间(RTT)、平面波近似方法和USBL导航解算方法及其坐标转换过程,结合INS误差方程,建立INS/USBL松组合模型。为进一步提高系统精度、动态性能和抗干扰性,考察USBL的原始斜距、斜距差以及声学基阵的空间分布信息,提出基于USBL原始输出信息的INS/USBL紧耦合组合导航方法。通过MATLAB仿真对导航算法进行验证,结果表明两种算法能充分抑制纯惯导误差随时间积累问题,且有效地估计出姿态、速度和位置误差角;其中紧耦合方法状态估计误差最小,导航参数精度相对松组合提高30%以上,对于提高水下载体导航定位精度、海洋探测具有重大意义。     

双向直驱式潮流能发电轮机性能实验研究

针对潮流能双向来流的特点及当前潮流能发电轮机的研究现状和存在的问题,提出了一种新型的双向直驱式发电轮机。叶片基本翼型为S型,并对其进行受力分析,得到相应的计算公式,结合叶片翼型厚度和形状约束,求解出各个截面的形状,并三维建模形成一种新型"S"翼型轮机。轮机两端安装具有防水性能的永磁发电机,外侧增设双向导流罩,构成双向直驱式发电轮机装置模型。在水槽实验中,首先找出不同的模拟流速下获取功率的最佳负载阻值,在此基础上收集了转速及功率数据,绘制尖速比-获能系数关系曲线图和流速—获能系数关系曲线图,可以论证尖速比的取值对获取最佳功率的重要性,同时该翼型轮机具有良好的空载启动性能及双向吸收来流的能力,2 m/s流速下获能效率最大值接近40%。     

Two Improvements on Numerical Simulation of 2-DOF Vortex-Induced Vibration with Low Mass Ratio

Till now, there have been lots of researches on numerical simulation of vortex-induced vibration. Acceptable results have been obtained for fixed cylinders with low Reynolds number. However, for responses of 2-DOF vortex-induced vibration with low mass ratio, the accuracy is not satisfactory, especially for the maximum amplitudes. In Jauvtis and Williamson''s work, the maximum amplitude of the cylinder with low mass ratio m*=2.6 can reach as large as 1.5D to be called as the “super-upper branch”, but from current literatures, few simulation results can achieve such value, even fail to capture the upper branch. Besides, it is found that the amplitude decays too fast in the lower branch with the RANS-based turbulence model. The reason is likely to be the defects of the turbulence model itself in the prediction of unsteady separated flows as well as the unreasonable setting of the numerical simulation parameters. Aiming at above issues, a modified turbulence model is proposed in this paper, and the effect of the acceleration of flow field on the response of vortex-induced vibration is studied based on OpenFOAM. By analyzing the responses of amplitude, phase and trajectory, frequency and vortex mode, it is proved that the vortex-induced vibration can be predicted accurately with the modified turbulence model under appropriate flow field acceleration.     

Remote sensing retrieval of surface suspended sediment concentration in the Yellow River Estuary

Accurate assessment of surface suspended sediment concentration(SSSC) in estuary is essential to address several important issues: erosion, water pollution, human health risks, etc. In this study, an empirical cubic retrieval model was developed for the retrieval of SSSC from Yellow River Estuary. Based on sediments and seawater collected from the Yellow River and southeastern Laizhou Bay, SSSC conditions were reproduced in the laboratory at increasing concentrations within a range common to field observations. Continuous spectrum measurements of the various SSSCs ranging from 1 to 5700 mg/l were carried out using an Ava Field-3 spectrometer. The results indicated the good correlation between water SSSC and spectral reflectance(Rrs) was obtained in the spectral range of 726–900 nm. At SSSC greater than 2700 mg/L, the 740–900 nm spectral range was less susceptible to the effects of spectral reflectance saturation and more suitable for retrieval of high sediment concentrations. The best correlations were obtained for the reflectance ratio of 820 nm to 490 nm. Informed by the correlation between Rrs and SSSC, a retrieval model was developed(R2 = 0.992). The novel cubic model, which used the ratio of a near-infrared(NIR) band(740–900 nm) to a visible band(400–600 nm) as factors, provided robust quantification of high SSSC water samples. Two high SSSC centers, with an order of 103 mg/l, were found in the inversion results around the abandoned Diaokou River mouth, the present Yellow River mouth to the abandoned Qingshuigou River mouth. There was little sediment exchange between the two high SSSC centers due to the directions of the residual currents and vertical mixing.     

Geochemistry,Zircon U–Pb Analysis,and Biotite 40Ar/39Ar Geochronology of the Maoling Gold Deposit,Liaodong Rift,NE China

The Maoling gold deposit is located in the southwestern part of the Liaodong rift, NE China, and has estimated reserves of 25 t. In this paper we present the results of an investigation into the geochronology and geodynamic mechanisms of igneous activity and metallogenesis within the Maoling gold deposit. New zircon U–Pb age data, biotite ⁴⁰Ar/³⁹Ar age data, whole‐rock geochemistry, and Hf isotopic analyses are presented in order to constrain the petrogenesis and mineralization of the deposit. Zircon U–Pb dating of the Wolongquan biotite monzogranite and Maoling biotite granite yielded mean ages of 194.0 ± 1.1 Ma and 196.1 ± 1.1 Ma, respectively. All the granites are characteristically high‐K calc‐alkaline, enriched in light rare earth elements and large ion lithophile elements, and depleted in high field strength elements, which is consistent with the geochemical characteristics of arc‐type magmas. The Hf isotope characteristics indicate that the granites formed by partial melting of early Paleoproterozoic crustal material. In addition, biotite ⁴⁰Ar/³⁹Ar dating indicates that the Maoling gold deposit formed at 188.9 ± 1.2 Ma, implying that the mineralization was related to both the granite intrusions. Taking into account previous data on S–Pb–O–H isotopes and our new age data, the Maoling deposit can be classified as an intrusion‐related gold deposit. Taking into account the geology of the study area and adjacent regions, we propose that the Maoling gold deposit and its associated granitic intrusions formed in a geodynamic setting that was dominated by subduction of the Paleo‐Pacific Plate beneath the Eurasian continent.     

Electron Probe Microanalysis of Bromine in Minerals and Glasses with Correction for Spectral Interference from Aluminium,and Comparison with Microbeam Synchrotron X‐Ray Fluorescence Spectrometry

The strong spectral interference between Br‐ and Al‐induced X‐ray lines hampers the utilisation of electron probe microanalysis (EPMA) for measuring Br mass fractions in Al‐bearing minerals and glasses. Through measuring Br‐free Al‐bearing materials, we established an EPMA method to quantify the overlap from AlKα on BrLβ, which can be expressed as a linear function of the Al₂O₃ content. The count rate of the BrLβ peak signal was enhanced by high beam currents and long measurement times. Application of this EPMA method to Al‐ and Br‐bearing materials, such as sodalite and scapolite, and to five experimental glasses yielded Br mass fractions (in the range of 250–4000 μg g^?1) that are consistent with those measured by microbeam synchrotron X‐ray fluorescence (μ‐SXRF) spectrometry. The EPMA method has an estimated detection limit of ~ 100–300 μg g^?1. We propose that this method is useful for measuring Br mass fractions (hundreds to thousands of μg g^?1) in Al‐bearing minerals and glasses, including those produced in Br‐doped experiments. In addition, the natural marialitic scapolite (ON70) from Mpwapwa (Tanzania) containing homogeneously distributed high mass fractions of Br (2058 ± 56 μg g^?1) and Cl (1.98 ± 0.03% m/m) is an ideal reference material for future in situ analyses.