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101.
基于神经-模糊方法的单料烟感官质量评价专家系统   总被引:3,自引:0,他引:3  
作者通过对单料烟评吸的结果与理化测定的指标参数进行分析 ,结合专家经验并采用神经 -模糊方法 ,提出一种基于单料烟的理化指标对各感官参数进行分类、分级 ,建造单料烟感官质量评价专家系统的方法。实验表明 ,该系统具有学习与知识提取能力 ,在卷烟产品质量管理新产品开发中具有指导意义  相似文献   
102.
厦门同安西柯对虾养殖池的细菌数量动态   总被引:10,自引:0,他引:10  
本文研究了对虾养成期间养殖池生态系中细菌的数量动态,探讨其变化规律与虾病的关系。结果表明,总细菌、弧菌和发光细菌在水体、底质和虾体中的数量变化各异。在水体各菌数与其环境因子的关系中,除了总菌数与COD存在着正相关外,其它的不存在相关性。虾体的总细菌、弧菌和发光细菌的数量(以细胞计)可以用来预报虾病,三者的阅值分别为107个 /g(湿重)、105个/g(湿重)和104介/g(湿重)。通过对对虾的细菌学跟踪监测,可以及时采取有效的应急防治措施。  相似文献   
103.
Baroclinic circulation in highly stratified and partially stratified estuaries is characterised by a two-layer flow: a bottom salt- water inflow and a surface brackish-water outflow. Tidal period variation of the thicknesses of a two-layer flow is observed to be associated with mixing, bottom stress and hydraulic characteristics of superposed tidal and gravity currents. Here, both analytical two-layer hydraulic equations with weak friction and a numerical model including a turbulence closure were utilised to understand the mechanism of the layer tendency within a two-layer flow under different barotropic flow conditions. It has been found that in the weak bottom friction case, a gravity current has two critical solutions at the layer thickness equal to 0·5Hand 0·292H. The layer thickness towards a particular critical solution is dependent on the sign of the bottom stress, i.e. when the bottom stress is opposite (favor) to the bottom gravity current, its layer thickness converges to 0·5H(0·292H). In the case of strong bottom stress and mixing opposing the gravity current, the solutions of the gravity current layer thickness at 0·5Hand 0·292Hwill not be valid. Both mixing and vorticity produced by bottom stress erode the halocline, and produce a high velocity core in the mid-depth, which leads to the thickness of a bottom gravity current greater than 0·5H. These internal hydraulic tendency and mixing processes, varying with time-dependent barotropic tidal current forcing, determine the tidal period variation of the gravity current structure.  相似文献   
104.
根据37年(1953~1989年)的有关气象资料分析表明,浙北地区当年3月温度,上年4~6月降水量,秋、冬季干湿度和年积温与当年东海热带气旋(指强度达到热带风暴以上的热带气旋以下统称台风)出现次数之间有着密切的相关性。在此基础上进一步分析了前期一些气象要素与登陆台风之间的关系,并由此分别建立预报东海台风出现多寡和台风是否登陆的判别式。从其拟合和试报结果来看,效果令人满意。  相似文献   
105.
西沙礁序列的磁性地层学研究   总被引:3,自引:0,他引:3  
利用西沙群岛西琛一井330m以上井段的149块岩心标本,用美国2-G型超导磁力仪进行了古地磁测定,获得了一个从更新世至中新世晚期包括布容,松山,高斯和吉尔伯特四个极性时及若干亚极性的磁性地层柱,为礁序列的划分对比,提供了新的依据。  相似文献   
106.
This paper presents the basis of acoustic method used for temperature field measurement of seafloor hydrothermal vent and two techniques of the parabolic interpolation and the bending compensation of propagation paths of acoustic signal are introduced. Experimental research is performed to exactly rebuild the temperature field around hot springs on the floor of Qiezishan Lake, Yunnan, China. The accuracy of the travel time estimation has been improved based on the aforementioned technique and method. At the same time, by comparison of the results of temperature field with different means, the max absolute error, the maximum relative error and the root mean square error are given. It shows that the technique and the method presented in the paper can be applied to the temperature field measurement detector around the seafloor hydrothermal vent. It also has a good accuracy.  相似文献   
107.
利用水饱和法制备含天然气水合物试样,进行等向压缩试验和不排水三轴试验.采用天然气水合物临界状态(M HCS)模型同时预测排水条件和不排水条件下的三轴试验,并进行变动参数分析.不排水条件下,密实纯砂发生应变硬化,而相近密实度的含水合物试样出现应变软化,峰值偏应力随水合物饱和度和围压增大.通过与排水和不排水三轴试验结果的对...  相似文献   
108.
This research investigated eight stations in Clarion-Clipperton Fracture Zone(CCFZ) in the eastern tropical Pacific in 2017 to study the spatial distribution characteristics of nutrients and chlorophyll a(Chl a) concentration,and compared nutrient concentrations and molar ratios with those of other investigations 20 years ago in the same area. The study found that dissolved inorganic nutrient(N, P and Si) concentrations were lowest in the upper layer, and increased from surface to some depths, t...  相似文献   
109.
Quantifying the gross and net production is an essential component of carbon cycling and marine ecosystem studies.Triple oxygen isotope measurements and the O_2/Ar ratio are powerful indices in quantifying the gross primary production and net community production of the mixed layer zone,respectively.Although there is a substantial advantage in refining the gas exchange term and water column vertical mixing calibration,application of mixed layer depth history to the gas exchange term and its contribution to reducing indices error are unclear.Therefore,two cruises were conducted in the slope regions of the northern South China Sea in October 2014(autumn) and June 2015(spring).Discrete water samples at Station L07 in the upper 150 m depth were collected for the determination of δ~(17)0,δ~(18)O,and the O_2/Ar ratio of dissolved gases.Gross oxygen production(GOP) was estimated using the triple oxygen isotopes of the dissolved O_2,and net oxygen production(NOP) was calculated using O_2/Ar ratio and O_2 concentration.The vertical mixing effect in NOP was calibrated via a N_2O based approach.GOP for autumn and spring was(169±23) mmol/(m~2·d)(by O_2) and(189±26) mmol/(m~2·d)(by O_2),respectively.While NOP was 1.5 mmol/(m~2·d)(by O_2) in autumn and 8.2 mmol/(m~2·d)(by O_2) in spring.Application of mixed layer depth history in the gas flux parametrization reduced up to 9.5% error in the GOP and NOP estimations.A comparison with an independent O_2 budget calculation in the diel observation indicated a26% overestimation in the current GOP,likely due to the vertical mixing effect.Both GOP and NOP in June were higher than those in October.Potential explanations for this include the occurrence of an eddy process in June,which may have exerted a submesoscale upwelling at the sampling station,and also the markedly higher terrestrial impact in June.  相似文献   
110.
In this paper, the intra-seasonal variability of the abyssal currents in the China Ocean Mineral Resources Association (COMRA) polymetallic nodule contact area, located in the western part of the Clarion and Clipperton Fraction Zone in the tropical East Pacific, is investigated using direct observations from subsurface mooring instruments as well as sea-surface height data and reanalysis products. Mooring observations were conducted from September 13, 2017 to August 15, 2018 in the COMRA contact area (10°N, 154°W). The results were as follows: (1) At depths below 200 m, the kinetic energy of intra-seasonal variability (20?100 d) accounts for more than 40% of the overall low-frequency variability, while the ratio reaches more than 50% below 2 000 m. (2) At depths below 200 m, currents show a synchronous oscillation with a characteristic time scale of 30 d, lasting from October to the following January; the energy of the 30-d oscillation increases with depth until the layer of approximately 4 616 m, and the maximum velocity is approximately 10 cm/s. (3) The 30-d oscillation of deep currents is correlated with the tropical instability waves in the upper ocean.  相似文献   
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