Surface chlorophyll in the Black Sea over 1978–1986 derived from satellite and in situ data

Absolute values of chlorophyll a concentration and its spatial and seasonal variations in the Black Sea were assessed by using satellite CZCS and in situ data. Since the satellite CZCS had operated for the 1978–1986 period, CZCS data was used for assessing the past state of the Black Sea just before the onset of drastic changes observed in late 1980s. The approach used for the calculation of the absolute values of chlorophyll a concentration from CZCS data was based on the direct comparison of in situ chlorophyll a data and those of CZCS and by applying the algorithm developed for the transformation of CZCS data into chlorophyll a values. CZCS Level 2 data related with pigment concentration having a spatial resolution of 1 km at nadir were used. The daily Level 3 files were derived by binning Level 2 values into 4-km grid cells and the monthly and seasonal Level 3 files were created by averaging the daily Level 3 files over the corresponding period. In situ chlorophyll a data were obtained by spectrophotometric and fluorometric methods in 15 scientific cruises over the 1978–1986 period. Total number of ship-measured data used for the comparison with those CZCS values was 590.Chlorophyll a concentration (Chl) was derived from CZCS values (C) with regression equations Chl=kC; the coefficient of transformation k was calculated from six different data sets by taking into account distinctions between subregions and seasons. The reasons for difference in the k values have been analyzed.Statistical comparison of the chlorophyll a values measured in situ and those derived from CZCS data was based on log-transformed data and gave the following results: regression SLOPE=0.842, regression INTERCEPT=−0.081, coefficient of determination (R²)=0.806, root–mean–square ERROR=0.195. The mean monthly chlorophyll a distributions derived from CZCS data over 1978–1986 have been constructed and the mean seasonal chlorophyll a values in different regions have been calculated and analyzed. The significant difference in chlorophyll concentration between the western shelf regions and the open part of the Black Sea has been demonstrated, especially in warm season. At almost all seasons, the highest chlorophyll concentration is observed in the western interior shelf region which is under strong influence of Danube. The summer mean chlorophyll concentration in this region is 18 times higher than that in the open parts and about nine times higher than in the eastern shelf region. The greatest seasonal variations are observed in the open part of the Black Sea: chlorophyll concentration in cold season is four to six times higher than in summer and three to five times higher than in April and October. To the contrary, in the western interior shelf regions, the concentration is higher in May–October (about twice than that in November–March). Seasonal variations in the western outer shelf regions are smoothed out as compared with both the western interior shelf and the open regions.     

基于 GJB7691-2012的通用数字示波器自动检定关键技术的研究*

作为一款时域电子测试仪器,示波器在科研、电力、医疗等多个方面得到了广泛的应用,随着计算机技术的不断进步,性能强大的数字示波器应运而生,同时,自动控制技术的普及使得数字示波器自动校准检定成为可能。论文以最新的数字示波器检定规程GJB7691‐2012为基础,针对新规程在检定与计算方法上的调整进行了分析,结合虚拟仪器与数据库技术完成了一种基于FLUK E9500B的通用数字示波器自动检定系统的设计,并就其关键技术进行了研究,同时通过试验结果比较验证了该方案的可靠性与可行性,并在计量工作中得到应用。     

Modbus协议在直流牵引供电系统中的应用

以直流牵引供电系统为例,提出了一种基于Modbus协议的通讯方式实现其内部通信。通过对直流牵引供电系统内部通信数据进行分析,采用RS485接口,运用Modbus协议实现了监控软件对微机保护装置和S7-200的串行通信,可靠地实现了系统内部各模块之间的通信,提高了系统的整体运行效率及可靠性。     

海口—海安航线客滚船轮机设计

介绍了海口—海安航线客滚船轮机设计的特点。通过调整机舱及辅助设备间布置方案,增加车道,提高了运能。对主推进系统布置中出现的问题提出了解决方法。针对航线特点合理配置应急/停泊发电机组,并介绍了该船消防系统布置特点及居住舱室和车辆舱排水能力计算方法及计算结果。设计中对货舱通风布置方案进行多次调整及优化。     

Environmental impact assessment of sediment dumping in the southern Baltic Sea using meiofaunal indicators

An experimental sediment dumping was carried out in the southern part of the Mecklenburg Bight in June 2001. Foraminiferans and ostracods from superficial sandy sediment were studied in a time series from before dumping until March 2004 in order to assess changes in associations and recolonization patterns of both groups. Additionally, an area sampling covering the dumping site and its surroundings from 15.5 to 20.7 m water depth made it possible to compare associations inside and outside the dumping area as well as the water depth dependent distribution of foraminiferans and ostracods. Salinity values vary within the high alpha-mesohaline and low polyhaline range. The dominating species are Ammotium cassis (Foraminifera) and Sarsicytheridea bradii (Ostracoda). The diversity is low (Fisher alpha index from 0.4 to 3.2 for foraminiferans and 1.0 to 2.5 for ostracods), but higher within the dumping site samples. These higher values are explainable by input of allochthonous tests and valves representing additional species. After the sediment dumping it took two and a half years to re-establish the total foraminiferan association and the total foraminifer/ostracod ratio within the dumping site. Total foraminiferan abundance increases remarkably with water depth (mean 83 tests in 100 ml) driven by higher nutrient availability and more suitable salinity and temperature values within the zone of the oscillating halocline. The distribution of shallow water species such as Cribroelphidium excavatum, Eucythere argus and Hirschmannia viridis, within the transient water layer A. cassis, Nodulina dentaliniformis, S. bradii and Palmoconcha laevata and below Eggerella scabra indicate the depth position of the halocline. Water depth and sediment dumping influence are the main driving factors for the distribution of foraminifer and ostracod associations within the study area. However, a significant sedimentological difference between samples inside and outside the dumping area is not recognizable.     

舰船高噪声环境下的语音编解码系统的实现

在研究语音编解码技术现状和发展趋势的基础上,针对舰船高噪声背景下语音信号的特点,利用DSP开发研制了一种语音编解码系统。详细阐述了系统的组成及工作原理,并采用自适应干扰抵消和G.729E相结合的方法,实现了低码率高语音质量的语音压缩与解压缩。     

基于NI虚拟仪器和nRF9E5单片机的串口通讯

针对多通道、长距离的数据传输,本文采用串口通讯方式,基于NI工控机和nRF9E5单片机硬件平台,并通过试验验证.     

基于Pro/E塑料顾问分析的塑料盒盖注射模具设计

针对传统模具设计的弊端,提出了采用模流分析技术对模具进行优化设计的思想。以Pro/E塑料顾问为平台,以塑料盒盖零件为实例,对其浇口位置进行计算机模拟分析,并在此基础上对塑料产品进行注射成型工艺模拟分析。综合分析结果有针对性地优化模具设计方案,避免了设计中的盲目性,提高了塑料产品的成型质量,减少了缺陷的产生,降低了生产成本,缩短了生产周期。     

基于 Pro／E 螺杆传动轴建模及利用 ANSYS 优化设计

针对千吨级注塑机螺杆传动轴在塑化、注射动作过程中失效断裂的分析研究,按静强度理论和疲劳强度理论对螺杆传动轴受复合变应力的状态下建立可靠的计算方法,以及应用计算机辅助设计Pro／E三维软件进行建模,通过ANSYS软件对传动轴进行有限元分析,并优化传动轴的结构来达到设计和使用要求。     

《白虎通义》声训的价值与不足

《白虎通义》的声训在训诂学史上有一定的地位和影响。其声训有助于音韵学研究,有助于推求语源,有助于系联同源词,有助于破假借;但也存在很多不足。文章对《白虎通义》声训的学术价值和不足之处作了简要的分析。