In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulatin...In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulating flume tank by using a model with an aspect ratio(AR) of 0.85 and a horizontal planform area( S) of 0.09 m^2. The results indicated that the critical angle( α_(cr)) of the model was 44°, whereas the maximum lift coefficient( C_(Lmax)) was up to 1.715, and the door efficiency( K) was 1.122. The attack angle( α) ranged from 30° to 48° and from 10° to 46° when the lift coefficient( C_L) and door efficiency( K) were greater than 1.2 and 1.0, respectively. To compare the difference between double-winged otter board and traditional Morgere Polyvalent Ovale, same model of Morgere Polyvalent Ovale was also tested under the same experimental conditions. The critical angle( α_(cr)) and maximum of lift coefficient( C_(Lmax)) of the doublewinged otter board were 37.5% and 14.6% larger than those of the Morgere Polyvalent Ovale. Therefore, we concluded that the novel, double-winged otter board was more suitable for bottom trawling fisheries in the deep water of the Mauretania Sea due to its better hydrodynamic characteristics and stability.展开更多
The Lucaogou Formation,located in the Jimsar Sag,Junggar Basin,NW China,has great potential for shale oil resources.In the process of CO_(2)-EOR(CO_(2) enhance oil recovery),mineral dissolution,precipitation and trans...The Lucaogou Formation,located in the Jimsar Sag,Junggar Basin,NW China,has great potential for shale oil resources.In the process of CO_(2)-EOR(CO_(2) enhance oil recovery),mineral dissolution,precipitation and transformation,leading to the local corrosion or blockage of reservoirs,have a significant influence on recovery.In this study,a combination of high-temperature and high-pressure laboratory experiments and coupled temperature/fluid-chemistry multifield numerical simulations are used to investigate CO_(2)-water-rock reactions under various reservoir conditions in the upper and lower ’sweet spots’,to reveal the mechanisms underlying CO_(2)-induced mineral dissolution,precipitation and transformation.In addition,we quantitatively calculated the evolution of porosity over geological timescales;compared and analyzed the variability of CO_(2) transformation in the reservoir under a variety of temperature,lithology and solution conditions;and identified the main factors controlling CO_(2)-water-rock reactions,the types of mineral transformation occurring during long-term CO_(2) sequestration and effective carbon sequestration minerals.The results demonstrate that the main minerals undergoing dissolution under the influence of supercritical CO_(2) are feldspars,while the main minerals undergoing precipitation include carbonate rock minerals,clay minerals and quartz.Feldspar minerals,especially the initially abundant plagioclase in the formation,directly affects total carbon sequestration,feldspar-rich clastic rocks therefore having considerable sequestration potential.展开更多
With the rise of the Internet and E-commence,it has become common for consumers in the book,clothing,electronic appliances,furniture and cosmetic industries to engage in a phenomenon termed"store-browsing-web-pur...With the rise of the Internet and E-commence,it has become common for consumers in the book,clothing,electronic appliances,furniture and cosmetic industries to engage in a phenomenon termed"store-browsing-web-purchasing"(SBWP).These are customers who tend to acquire service and information about particular products at traditional(brick and motar)retail stores but purchase them online at a lower price.This creates new issues and new perspectives to the science of law and economics.This paper addresses the issue of SBWP based on the industrial organization theory(especially the vertical dual-pricing system).It then endeavors to demonstrate the three"jump-dealing"theorems of SBWP from analyzing the business models,consumer purchasing patterns and price differences in distributing channels.Furthermore,we extrapolate the theory of jump-dealing and resale price maintenance(RPM)offsetting based on previous findings.The main conclusions are the following:if a company's RPM strategies substantially eliminate competition,then jump-dealing behavior from consumers shouM be encouraged.Conversely,if this jump-dealing behavior from consumers brings about anti-competition and free riding problems,then a company's RPM strategies should be exempted.展开更多
基金Supported by the Technological Research on Reforming Otter Boards of Bottom Trawl in Mauretania and Guinea(China National Fisheries Corporation,CNFC)Technological Research on Transformation and Upgrading of Shrimp Trawl in Sierra Leone(CNFC)Far Sea Fisheries Resources Monitoring and Assessment of South China Sea(No.2013050212)
文摘In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulating flume tank by using a model with an aspect ratio(AR) of 0.85 and a horizontal planform area( S) of 0.09 m^2. The results indicated that the critical angle( α_(cr)) of the model was 44°, whereas the maximum lift coefficient( C_(Lmax)) was up to 1.715, and the door efficiency( K) was 1.122. The attack angle( α) ranged from 30° to 48° and from 10° to 46° when the lift coefficient( C_L) and door efficiency( K) were greater than 1.2 and 1.0, respectively. To compare the difference between double-winged otter board and traditional Morgere Polyvalent Ovale, same model of Morgere Polyvalent Ovale was also tested under the same experimental conditions. The critical angle( α_(cr)) and maximum of lift coefficient( C_(Lmax)) of the doublewinged otter board were 37.5% and 14.6% larger than those of the Morgere Polyvalent Ovale. Therefore, we concluded that the novel, double-winged otter board was more suitable for bottom trawling fisheries in the deep water of the Mauretania Sea due to its better hydrodynamic characteristics and stability.
基金funded by grants from the Beijing Natural Science Foundation (Grant No. 8232044)the Natural Science Foundation of the Xinjiang Uygur Autonomous Region (Grant No. 2021D01F38)China Geological Survey Second-level Project (Grant No. DD20230025)。
文摘The Lucaogou Formation,located in the Jimsar Sag,Junggar Basin,NW China,has great potential for shale oil resources.In the process of CO_(2)-EOR(CO_(2) enhance oil recovery),mineral dissolution,precipitation and transformation,leading to the local corrosion or blockage of reservoirs,have a significant influence on recovery.In this study,a combination of high-temperature and high-pressure laboratory experiments and coupled temperature/fluid-chemistry multifield numerical simulations are used to investigate CO_(2)-water-rock reactions under various reservoir conditions in the upper and lower ’sweet spots’,to reveal the mechanisms underlying CO_(2)-induced mineral dissolution,precipitation and transformation.In addition,we quantitatively calculated the evolution of porosity over geological timescales;compared and analyzed the variability of CO_(2) transformation in the reservoir under a variety of temperature,lithology and solution conditions;and identified the main factors controlling CO_(2)-water-rock reactions,the types of mineral transformation occurring during long-term CO_(2) sequestration and effective carbon sequestration minerals.The results demonstrate that the main minerals undergoing dissolution under the influence of supercritical CO_(2) are feldspars,while the main minerals undergoing precipitation include carbonate rock minerals,clay minerals and quartz.Feldspar minerals,especially the initially abundant plagioclase in the formation,directly affects total carbon sequestration,feldspar-rich clastic rocks therefore having considerable sequestration potential.
基金supported by National Natural Science Foundation of China(Grant No.71272190,"The B-T-C Paradigm and Application for'Jump-Dealing'Problems")
文摘With the rise of the Internet and E-commence,it has become common for consumers in the book,clothing,electronic appliances,furniture and cosmetic industries to engage in a phenomenon termed"store-browsing-web-purchasing"(SBWP).These are customers who tend to acquire service and information about particular products at traditional(brick and motar)retail stores but purchase them online at a lower price.This creates new issues and new perspectives to the science of law and economics.This paper addresses the issue of SBWP based on the industrial organization theory(especially the vertical dual-pricing system).It then endeavors to demonstrate the three"jump-dealing"theorems of SBWP from analyzing the business models,consumer purchasing patterns and price differences in distributing channels.Furthermore,we extrapolate the theory of jump-dealing and resale price maintenance(RPM)offsetting based on previous findings.The main conclusions are the following:if a company's RPM strategies substantially eliminate competition,then jump-dealing behavior from consumers shouM be encouraged.Conversely,if this jump-dealing behavior from consumers brings about anti-competition and free riding problems,then a company's RPM strategies should be exempted.
