水利水电库区漂浮污物智能化综合治理技术进展

开展水利水电库区漂浮污物智能化综合治理技术研究和应用是至关重要。笔者团队经过多年的研究攻关,探索出了一套“估漂—拦漂—清漂—用漂”一体化智能化综合治理技术。研究结合水文、气象大数据信息及库区环境状况,对水面漂浮污物的来量提前进行预判;分析了行业内拦漂技术的痛点和难点,研发了适应水流速度大、水位变幅高、防翻转、防沉没的拦漂系统,实现了不同工况下水面漂浮污物的高效拦截;采用多传感系统与人工智能相融合的新一代信息技术,攻克了水面漂浮污物强识别、防误判的关键技术,研制了水面漂浮污物智能识别、自动打捞的高效清污机器人系列产品;开发了将漂浮污物快速制成有机肥、生物质燃料的资源化利用设备,解决了水面漂浮污物上岸后无害化处理的难题。相关研究突破了水面漂浮污物智能化治理的多项关键技术,从漂浮污物来量估计、高效拦截、智能打捞、无害化处理及循环利用多个方向全面开展研究工作,构建了水面漂浮污物一体化的综合解决方案,为水利水电工程的安全运行起到了积极作用。

A Numerical Study on the Density Driven Circulation in the Yellow Sea Cold Water Mass

The circulation of Yellow Sea Cold Water Mass （YSCWM） in the Southern Yellow Sea is investigated using a diagnostic 2D MITgcm model. The resolution of the computational grid is 900 m in the horizontal and 2 m in the vertical where an initial tem- perature distribution corresponding to a typical measured Yellow Sea Cold Water Mass was applied. The existence of YSCWM that causes fluid density difference, is shown to produce counter-rotating cyclonic horizontal eddies in the surface layer： the inner one is anti-cyclonic （clockwise） and relatively weaker （8-10cms-1） while the outer one is cyclonic （anti-clockwise） and much stronger （15-20cms-~）. This result is consistent with the surface pattern observed by Pang et al. （2004）, who has shown that a mesoscale anti-cyclonic eddy （clockwise） exists in the upper layer of central southern Yellow Sea, and a basin-scale cyclonic （anticlockwise） gyre lies outside of the anti-cyclonic eddy, based on the trajectories and drifting velocities of 23 drifters. Below the thermocline, there is an anti-cyclonic （clockwise） circulation. This complex current eddy system is considered to be capable of trapping suspended sediments and depositing them near the front between YSCWM and the coastal waters off the Subei coast, providing an explanation on the sediment depth and size distribution of mud patches in the Southern Yellow Sea. Moreover, sensitive test scenarios indicate that variations of bottom friction do not substantially change the main features of the circulation structure, but will reduce the bottom current velocity, increase the surface current velocity and weaken the upwelling around the frontal area.

Application of Intensive Closed-type Float System in Tobacco Nursery

Due to the continuous low temperature during the early-nursery period in most tobacco-growing areas in Guizhou Province, the tobacco seed germinate slow-ly, the nursery period is prolonged, the quality of tobacco seedlings are not that good, the transplanting is delayed, etc. A comparative test of intensive closed-type floating-seedling system and conventional floating-seedling system was carried out in this study. The results showed that the intensive closed-type floating system could shorten significantly the nursery period; enhance the growth of tobacco seedlings;improve significantly the appearance of agronomic traits, such as number of leaves, stem height, stem diameter, fresh weight of leaves, etc; increase slightly the chloro-phyl content in seedlings. However, the root fresh weight and root vigor of seedlings nursed with the intensive closed-type float system were lower than that of seedlings nursed with the conventional float system. The intensive closed-type float system had a certain application potential in tobacco production.

The Joint Distribution of the Maximum Excursion and the Minimum Excursion for Brownian Motion with Drift

In this paper, we discuss the problem of extreme value for Brownian motion with positive drift. We obtain the joint distribution of the maximum excursion and the minimum excursion.

NAND flash service lifetime estimate with recovery effect and retention time relaxation

A service life model of NAND flash and threshold voltage shift process is proposed to calculate the service life and endurance.The relationships among achievable program/erase(P/E) cycles,recovery time,bad block rate and storage time are analyzed.The achievable endurance and service life of a NAND flash are evaluated based on a flash cell degradation and recovery model by varying recovery time,badblock rate,and storage time.It is proposed to improve the service lifetime of solid state disk by both relaxing the bad block rate limitation and retention time while extending the recovery time.The results indicate that endurance can be improved by 17 times if the storage time guarantee is reduced from 10 a to 1 a with 105 s recovery time inserted between cycles.

Ecological Costs Applied in the Bleaching of Cotton： A Study for an Optimized Process

The aim of this paper was to study three variables in hydrogen peroxide bleaching of cotton fabrics： the amount of hydrogen peroxide （H2O2）, peroxide stabilizer （Na2SiO3） and the process temperature. The factorial planning of two levels and three factors was done in order to obtain an optimized recipe for subsequent comparison with commons recipes used in industry. Were evaluated the brightness （DL）, energy consumption （dQ）, H2O2 residual （Rox）, processing time and ecological costs.

Improved Ligand-Field Calculation of Energy Spectrum and R-Line Thermal Shift of MgO：Cr^3＋

Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one （including lattice-vibrational relaxation energy）. By means of improved ligand-field theory, the R-line, t^3 2^2 T1 lines, t^2 2（^3 T1）e^4 T2, and t^2 2（^3T1）e^4T1 bands, ground-state g factor, four strain-induced level- splittings, and R-line thermal shift of MgO：Cr^3＋ have been calculated. The results are in very good agreement with the experimental data. It is found that for MgO：Cr^3＋, the contributions due to electron-phonon interaction （EPI） come from the first-order term. In thermal shift of R-line of MgO：Cr^3＋, the temperature-dependent contribution due to EPI is dominant.

Geomorphic Habitat Type, Drift Cell, Forage Fish and Juvenile Salmon： Are They Linked？

The role of geomorphic habitat type, drift cell scale, and geographic scale in defining fish use of nearshore habitats is poorly known, particularly for Pacific salmon and their prey. In this study, key areas of nearshore habitat in central and western Strait of Juan de Fuca were categorized by geomorphic habitat type and assessed for fish use within a degraded （Elwha） and intact comparative drift cells over a one year period. Juvenile Chinook and coho salmon were also sampled for genetic analysis to define regional dispersal patterns. Key findings are： （1） Ecological function of the area＇s nearshore is complex, with very strong seasonal variation in fish use both within and across GMHT （geomorphic habitat type）; （2） GMHT link to nearshore function for fish use differs depending on the fish species and time of year. Surf smelt and sand lance were the most abundant. And they were seasonally used embayed, spit, and bluff shorelines more than lower rivers. Juvenile Chinook, coho, and chum salmon occurred in much lower density than forage fish species, and used lower rivers more than other GMHTs; （3） When GMHTs were combined and analyzed at the drift cell scale, the degraded drift cell had different ecological patterns than the intact drift cell; （4） Cross regional juvenile fish use of nearshore is an important component of habitat use： juvenile Chinook and coho from as far away as the Columbia River Oregon and Klamath River California utilize central Strait of Juan de Fuca shorelines. Forage fish species may do so as well. Drift cell and cross regional scales are therefore most important for accurately defining nearshore ecological function, management, and restoration actions.

Emergent plant presence and richness alter competitive interactions between two foating plants

Interactions between two plant species can be infuenced by the presence of other plant species and such an effect may change as the diversity of the other species increases.To test these hypotheses,we frst constructed aquatic communities consisting of 1,2 and 4 emergent plant species and then grew ramets of Lemna minor only,ramets of Spirodela polyrhiza only or ramets of both L.minor and S.polyrhiza within these aquatic communities.We also included controls with ramets of L.minor,S.polyrhiza or both but without any emergent plants.Biomass and number of ramets of L.minor and S.polyrhiza were signifcantly smaller with than without the emergent plants,but they did not differ among the three richness levels.The presence of S.polyrhiza did not signifcantly affect the growth of L.minor,and such an effect was not dependent on the richness of the emergent plant species.Without the emergent plant species,the presence of L.minor markedly reduced biomass(-92%)and number of ramets(-88%)of S.polyrhiza.However,such a competitive effect of L.minor on S.polyrhiza became much weaker in the presence of one emergent plant species(-46%biomass and-39%number of ramets)and completely disappeared in the presence of two or four emergent plant species.Therefore,both the presence and richness of emergent plant species can alter competitive interactions between the two duckweed species.These fndings highlight the importance of species diversity in regulating plant-plant interactions.