网络观测计的研究和实现

介绍了网络测量的核心部件网络观测计的功能和各部分组成,给出了观测计实现的模块流程图,并讨论其实现中的几个关键问--题。

临安 建成全球首座竹林碳汇通量观测塔

经过长期的研究和筹备,由浙江农林大学分别和临安市林业局、安吉县林业局共同建设的雷竹林碳汇通量观测塔、毛竹林碳汇通量观测塔。

Research of CRP-based irregular 2D seismic acquisition

Seismic exploration in the mountainous areas of western Chinese is extremely difficult because of the complexity of the surface and subsurface, which results in shooting difficulties, seismic data with low signal-to-noise ratio, and strong interference. The complexity of the subsurface structure leads to strong scattering of the refl ection points; thus, the curved-line acquisition method has been used. However, the actual subsurface structural characteristics have been rarely considered. We propose a design method for irregular acquisition based on common refl ection points（CRP） to avoid difficult-to-shoot areas, while considering the structural characteristics and CRP positions and optimizing the surfacereceiving line position. We arrange the positions of the receiving points to ensure as little dispersion of subsurface CRP as possible to improve the signal-to-noise ratio of the seismic data. We verify the applicability of the method using actual data from a site in Sichuan Basin. The proposed method apparently solves the problem of seismic data acquisition and facilitates seismic exploration in structurally complex areas.

Designing optimal number of receiving traces based on simulation model

Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the optimal number of receiving traces in field geometry using a numerical simulation based on a field test conducted in previous research （Zhu et al., 2011）. A mathematical model is established for total energy and average efficiency energy using fixed trace spacing and optimal receiving traces are estimated. Seismic data acquired in a complex work area are used to verify the correctness of the proposed method. Results of model data calculations and actual data processing show that results are in agreement. This indicates that the proposed method is reasonable, correct, sufficiently scientific, and can be regarded as a novel method for use in seismic geometry design in complex geological regions.

轻化论——大趋势的思考

当今世界,不少学者都将目光投向未来。尤其在新技术革命浪潮的推动下,国外研究预测经济社会发展大趋势新浪潮的论著相继问世。笔者也曾就产业结构进行过“轻化”大趋势的初步思考。提到了产品不断减重、提质、增殖的发展趋势。然而,“轻化”及其轻化现象、轻化趋势,绝不仅只在产业结构的范围内表现出进步意义,在中国。

日本的南极考察站

1957～1958年国际地球物理观测计划的主要目的,是在南极大陆建立观测网,进行综合性观测。第二次世界大战结束10年之后,战败国日本刚刚开始重返国际社会,在连主食大米也匮乏的复苏年代,该国有关决策人就作出决断,参加了这一国际合作的大事业。日本的南极考察站,当时被许可建在东径20°～50°的大陆沿岸的一片人迹未到的地区。

Estimation of Geodetic Parameters with VLBI Data of Last 5 Years

The meaning to research the potential of VLBI for geodetic applications is summarized. And the observation models and their related parameters of geodetic interest are investigated. Then, the principle and method of using the random model in VLBI data processing are investigated. With the world wide VLBI data from 2000-2004, the conditions to compute the parameters of geodetic interest are introduced, and so are the computing methods and processes. And the computed resuits of the parameters of geodetic interest are analyzed.

Evaluation of Latest TMPA and CMORPH Precipitation Products with Independent Rain Gauge Observation Networks over High-latitude and Low-latitude Basins in China

The Tropical Rainfall Measuring Mission （TRMM） Multi-satellite Precipitation Analysis （TMPA） and National Oceanic and Atmospheric Administration （NOAA） Climate Prediction Center （CPC） morphing technique （CMORPH） are two important multi-satellite precipitation products in TRMM-era and perform important functions in GPM-era. Both TMPA and CMORPH systems simultaneously upgraded their retrieval algorithms and released their latest version of precipitation data in 2013. In this study, the latest TMPA and CMORPH products （i.e., Version-7 real-time TMPA （T-rt） and gauge-adjusted TMPA （T-adj）, and Version- 1.0 real-time CMORPH （C-rt） and Version-l.0 gauge-adjusted CMORPH （C-adj）） are evaluated and intercompared by using independent rain gauge observations for a 12-year （2000--2011） period over two typical basins in China with different geographical and climate conditions. Results indicate that all TMPA and CMORPH products tend to overestimate precipitation for the high-latitude semiarid Laoha River Basin and underestimate it for the low-latitude humid Mishui Basin. Overall, the satellite precipitation products exhibit superior performance over Mishui Basin than that over Laoha River Basin. The C-adj presents the best performance over the high-latitude Laoha River Basin, whereas T-adj showed the best performance over the low-latitude Mishui Basin. The two gauge-adjusted products demonstrate potential in water resource management. However, the accuracy of two real-time satellite precipitation products demonstrates large variability in the two validation basins. The C-rt reaches a similar accuracy level with the gauge-adjusted satellite precipitation products in the high-latitude Laoha River Basin, and T-rt performs well in the low-latitude Mishui Basin. The study also reveals that all satellite precipitation products obviously overestimate light rain amounts and events over Laoha River Basin, whereas they underestimate the amount and events over Mishui Basin. The findings of the precision characteristics associated with the latest TMPA and CMORPH precipitation products at different basins will offer satellite pre- cipitation users an enhanced understanding of the applicability of the latest TMPA and CMORPH for water resource management, hydrologic process simulation, and hydrometeorological disaster prediction in other similar regions in China. The findings will also be useful for IMERG algorithm development and update in GPM-era.

Influence of assimilating ground-based microwave radiometer data into the WRF model on precipitation

Ground-based microwave radiometers profilers(MWRPs)have been used in numerical weather prediction(NWP)systems and show different impacts on forecasts.Currently,there are around hundreds of ground-based MWPRs used in weather stations over China;however,the application of MWPRs in NWP systems is rather limited.In this work,two MWRP retrieved profiles were assimilated into the Weather Research and Forecasting(WRF)model for a rainstorm event that occurred in Beijing,China.The quality of temperature and humidity profiles retrieved from the MWRP was evaluated against radiosonde observations and showed the reliability of the two MWRP products.Then,comparisons between the measurements of ground-based rain gauges and the corresponding forecasted precipitation in different periods of the rainstorm were investigated.The results showed that assimilating the two MWRPs affected the distribution and intensity of rainfall,especially in the early stage of the rainstorm.With the development of the rainstorm,adding MWRP data showed only a slight influence on the precipitation during the stable and mature period of the rainstorm,since the two MWRP observations were too limited to affect the large area of heavy rainfall.

NOVEL SENSORLESS VECTOR CONTROL SYSTEM OF INDUCTION MACHINE BASED ON FLUX OBSERVER IN FIELD WEAKENING

A speed-sensorless vector control system for induction machines （IMs）is presented, According to the vector control theory of IMs, the rotor flux is estimated based on a flux observer,and the speed is estimated through the method of q-axis rotor flux converging on zero with proportional integral regulator, A 0.75 kW,50 Hz,two-pole induction machine was used in the simulation and experimental verification, The simulation model was constructed in Matlab. A series of tests were performed in the field weakening region, for both no-load and loaded operation. The estimated speed tracks the actual speed well in the based speed region and field weakening region （ 1 per unit value to 4 per unit value）. The small estimation error of residual speed is due to the existence of slip.

LMI Approach to Mixed H_/H_∞ Fault Detection Observer Design

To investigate the robust fault detection （RFD） observer design for linear uncertain systems, the H_index and H∞ norm are used to describe this observer design as optimization problems. Conditions for the existence of such a fault detection observer are given in terms of matrix inequalities. The solution is obtained by new iterative linear matrix inequality （ILMI） algorithms. The RFD observer design over finite frequency range in which Of does not have full column rank for a system is also considered. Numerical example demonstrates that the designed fault detection observer has high sensitivity to the fault and strong robustness to the unknown input.

Global Robust and Adaptive Output Feedback Dynamic Positioning of Surface Ships

A constructive method was presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances induced by waves, wind, and ocean currents. The ship's parameters were not required to be known. An adaptive observer was first designed to estimate the ship's velocities and parameters. The ship position measurements were also passed through the adaptive observer to reduce high frequency measurement noise from entering the control system. Using these estimate signals, the control was then designed based on Lyapunov's direct method to force the ship's position and orientation to globally asymptotically converge to desired values. Simulation results illustrate the effectiveness of the proposed control system. In conclusion, the paper presented a new method to design an effective control system for dynamic positioning of surface ships.

ROBUST OBSERVER DESIGN FOR A CLASS OF UNCERTAIN NONLINEAR LARGE SCALE SYSTEMS *

In this paper, a mathematic description of a class of uncertain nonlinear large scale systems based on some practical application is given. A designing method to construct observers for such kind of nonlinear composite systems is developed. The unknown parameters and disturbances are assumed to be neither linear nor matched. A numerical example is used to illustrate the efficiency of our results.

Research and Design of Drop Keel System for Multi-purpose Oceanographic Vessel

When an oceanographic vessel is sailing, the currents near the surface of ship hull are rapid, making it hard to meet the environmental requirements of scientific observation equipment. To guarantee the installation space and environmental requirements of the observation equipment, the drop keel system was proposed for the first time for ocean-graphic ships at China, to avoid the traditional ＂rudder-shaft＂ type fin keel＇s disadvantage. The research study will examine the operational mechanism and functions of the drop keel system, the operating conditions of the fin keel to determine the driver method and its arrangement, and the locking method of the fin keel underwater. The research wilI also provide some general designs for analyzing the best plan for the drop keel system.

Study on unknown input reduced-order observer for fault diagnosis

A novel unknown input reduced-order observer (UIRO) design scheme is presented. It is proved that unknown input appearing in measurement can be eliminated by a simple algebraic transformation. Then, a new UIRO design scheme is proposed via a transformation under no unknown input existing in measurement. Compared with other known results, the condition is weaker than others. So it was further reasonable. The design procedure proposed is simple and straightforward enough to be applied. An example is given to show its efficiency in fault diagnosis.

ON THE KEY REGIONS OF 500 hPa GEOPOTENTIAL HEIGHTS OVER NORTHERN HEMISPHERE IN WINTER

Variance analysis, correlation analysis and regression analysis methods are applied to analyze the variation of circulation at 500 hPa. In winter, there are three regions (180°E – 150°W, 45°N – 60°N, 70°W – 100 °W,45°N – 75°N, 60°E – 100°E, 65°N – 80°N) whose variations are strong. Those regions are the key regions in which atmospheric circulation can change. Those regions are correlated to some teleconnections and can present a part of variations of 500 hPa to some degree. The linear contemporary correlation between those regions and the height at 500 hPa is significant. Those regions can account for 88 % of variations of concurrent height at 500 hPa. Those regions can present and forecast some variations to some degree in March and April. The longer the time interval, the worse the forecast effect will be. The interannual variations of Q1, Q2 and the SST are weak in the western Pacific.

Spectral Studies of Oscillations Observed by the High-Latitude Radar and Magnetometers

A comparative spectral analysis of high-latitude magnetic and Doppler radar measurements is presented. The analysis takes into account the Doppler effect that is inherent in magnetic observations. The frequency shifts between the magnetic and radar data are estimated （removed） indirectly by formulating the spectral analysis of magnetic data as the Schuster problem of hidden periodicities. There is a satisfactory agreement between the basic frequencies of equidistant spectra found in the magnetic data and frequencies found in the corresponding Doppler radar data. Some conclusions relevant to these findings are discussed.

Experimental and field study on dissipation coefficient of supersaturated total dissolved gas

The elevated supersaturation of total dissolved gas （TDG） downstream of a high-dam spill has deleterious effects on fish in a large range. A one-dimensional （l-D） longitudinal model is optimal for the prediction of supersaturated TDG dissipation over a long distance. The key issue of the model is to determine the dissipation coefficient accurately. In agreement with field observations and experiment data, dimensional analysis and regression were performed to propose a formula for estimating the dissipation coefficient of supersaturated TDG in various rivers and reservoirs, and it involves the effects of the turbulence intensity, the hydro-pressure and the solid-liquid interface. The friction velocity, water depth, hydraulic radius and Froude number are independent variables in the formula which are easy to determine in practical applications. The 1-D longitudinal model is implemented to calculate the dissipation of TDG in a reach of the Jinsha River. Good agreement is found between the calculated results and field data for both the dissipation coefficient and the dissipation process.

Analyses of Characteristics of Long-Term Monitoring of Arterial Pressure and Pulse

Long-term observations of pulse and arterial blood pressure taken from a patient＇s daily self-control diary have been analyzed in the paper. The diary was kept in the morning and in the evening. It contains regular observational data collected during over 13 years. Statistical estimates of series and their spectral responses were obtained. A difference between the morning and evening series was noted. Spectral harmonics with the period of 7 days was typical of the evening series. The morning series are characterized by a ＂lunar＂ component with the -27.35-day period. The examined series were also compared with the daily series of atmospheric pressure and daily Wolf numbers. Seasonal pulse and arterial pressure pattern and average monthly self-control tabulated data obtained during 13 years are presented in the paper.

Theoretical Study on Drift of Ca^(2+)Spiral Waves Controlled by Electric Field

Based on the Tang-Othmer Ca^2＋ model, the drift behavior of intracellular Ca^2＋ spiral waves under the influence of weak electric field is investigated. Numerical results show that the dependence of drift velocity of the spiral tip on dc electric field is similar to experimental observations in BZ system. When an ac electric field is applied, interesting resonant-drift phenomenon is observed with ω=2ω0. All results can be explained analytically using a proximate method.