Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop （Patinopecten yessoensisis Ja...Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop （Patinopecten yessoensisis Jay, 1857） larval development stages. The aim of this study was to characterize and compare the bacterial communities associating with Yesso scallop larval development at fertilized egg S l, trochophora S2, D-shaped larvae S3, umbo larvae S4, and juvenile scallop S5 stages by Illumina high-throughput sequencing. Genomic DNA was extracted from the larvae and their associating baetera, and a gene segment covering V3-V4 region of 16S rRNA gene was amplified and sequenced using an Illumina Miseq sequencer. Overall, 106760 qualified sequences with an average length of 449 bp were obtained. Sequences were compared with those retrieved from 16S rRNA gene databases, and 4 phyla, 7 classes, 15 orders, 21 families, 31 genera were identified. Proteobacteria was predominant phylum, accounting for more than 99%, at all 5 larval development stages. At genus level, Pseudomonas was dominant at stages S1 （80.60%）, S2 （87.77%） and S5 （68.71%）, followed by Photobacterium （17.06%） and Aeromonas （1.64%） at stage S1, Serratia （6.94%）, Stenotrophomonas （3.08%） and Acinetobacter （1.2%） at stage S2, Shewanella （25.95%） and Pseudoalteromonas （4.57%） at stage S5. Moreover, genus Pseudoal- teromonas became dominant at stages S3 （44.85%） and S4 （56.02%）, followed by Photobacterium （29.82%）, Pseudomonas （11.86%）, Aliivibrio （8.60%） and Shewanella （3.39%） at stage S3, Pseudomonas （18.16%）, Aliivibrio （14.29%）, Shewanella （4.11%）, Psychro- monas （4.04%） and Psychrobacter （1.81%） at stage S4. From the results, we concluded that the bacterial community changed sig- nificantly at different development stages of Yesso Scallop larvae.展开更多
The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decreas...The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decrease sharply from Hangzhou Bay to the offshore area. Suspended sediment transport is mainly controlled by advection transport and gravitational circulation transport. The settling velocity of suspended sediments gradually decreases from Hangzhou Bay to the offshore area. The settlement of suspended sediments mainly takes place during the turning phase of the tidal currents.展开更多
This paper proposed that the flow characteristic of electronic expansion valve should be adapted to the evaporator superheat gain to refrigerant flow rate under different working conditions. Two native methods of geom...This paper proposed that the flow characteristic of electronic expansion valve should be adapted to the evaporator superheat gain to refrigerant flow rate under different working conditions. Two native methods of geometry modeling of electronic expansion valve head were introduced. By analysis of them, some shortcoming was detected and a universal modeling method of electronic expansion valve head was put forward. Through this model, the flow characteristic of EEV and the influence factors can be investigated more deeply.展开更多
Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated nu...Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows： during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool＇s displacement of the safety valve, and it can be used to control the high-flow three-way valve＇s sensitivity.展开更多
Because of the difficulties of describing the process of combustion of underground mine fires, usually the fire seat is considered as a fixed point in the methods of mine fire computer simulation, however this is not ...Because of the difficulties of describing the process of combustion of underground mine fires, usually the fire seat is considered as a fixed point in the methods of mine fire computer simulation, however this is not in keeping with the feature of the distribution of the combustibles and the process of combustion in mine fires. A conception about movable linear fire seat is put forward first by the authors, together with the calculated models of the thermal decomposition rate, flame spreading velocity and the steady burning length of a linear fire seat etc. The paper also introduces the results of the application of these models.展开更多
The denitrifying sulfide removal(DSR) process has recently been studied extensively from an engineering perspective. However, the importance of microbial communities of this process was generally underestimated. In th...The denitrifying sulfide removal(DSR) process has recently been studied extensively from an engineering perspective. However, the importance of microbial communities of this process was generally underestimated. In this study, the microbial community structure of a lab-scale DSR reactor was characterized in order to provide a comprehensive insight into the key microbial groups in DSR system. Results from high-throughput sequencing analysis revealed that the fraction of autotrophic denitrifiers increased from 2.34 % to 10.93% and 44.51% in the DSR system when the influent Na Cl increased from 0 g/L, to 4 g/L and 30 g/L, respectively. On the contrary, the fraction of heterotrophic denitrifiers decreased from 61.74% to 39.57%, and 24.12%, respectively. Azoarcus and Thiobacillus were the main autotrophic denitrifiers, and Thauera was the main hetetrophic denitrifier during the whole process. This study could be useful for better understanding the interaction between autotrophs and heterotrophs in DSR system.展开更多
This study evaluates the spatial distributions in the quality of momentum and sensible heat fluxes,and determines the turbulent transfer characteristics with quality-controlled observations.The research is based on ra...This study evaluates the spatial distributions in the quality of momentum and sensible heat fluxes,and determines the turbulent transfer characteristics with quality-controlled observations.The research is based on raw turbulence data collected over a Gobi surface in the Dunhuang area in June 2004.The results indicate that part of the momentum fluxes are of poor quality in the daytime and nighttime.The poor quality of the momentum fluxes in the daytime is mainly attributed to the development of turbulence.The footprint reveals that,in general,the momentum fluxes and sensible heat fluxes can be measured well in the east and west upwind sectors under unstable conditions.The relationship between the non-dimensional standard deviation of the wind components and atmospheric stability follow the "1/3 power law",which supports the Monin-Obukhov similarity theory.Moreover,this study identifies a clear disturbance in the measurements surrounding the Gobi surface.The momentum roughness length of z0m=0.59 mm is determined after excluding such disturbance,and the additional resistance during the daytime is proposed to be an average of 3.1,although its actual value is highly scattered.This study discusses the applicability of several thermodynamic parameterization schemes for the Gobi surface.The results show that the scheme κB-1=3.1 can represent well the summer diurnal turbulent heat transfer.展开更多
The free flow on the step surfaces has received much attention for its representative body type,flow structure,water-air two phase flow,cavitation,and many complex issues.The experiments about the time-averaged pressu...The free flow on the step surfaces has received much attention for its representative body type,flow structure,water-air two phase flow,cavitation,and many complex issues.The experiments about the time-averaged pressure and aeration concentration distribution on the step surface show that the vertical plane of steps will inevitably experience negative pressure,which must rely on adequate aeration concentration to avoid cavitation damage.However,the self-aerated flow at the head section has a relatively low aeration concentration,and the concentration of the entire steps decreases with the increasing of weir head,the minimum appears in the vicinity of the corner,and the location is close to the minimum pressure.Thus,it is necessary to set aerator in the upstream end of the step surfaces to avoid cavitation damage.展开更多
Spray structure and atomization characteristics were investigated through a comparison of a porous and a shear coaxial injector. The porous injector shows better atomization performance than the shear coaxial injector...Spray structure and atomization characteristics were investigated through a comparison of a porous and a shear coaxial injector. The porous injector shows better atomization performance than the shear coaxial injector. To in- crease atomization performance and mixing efficiency of two-phase jets, a coaxial porous injector which can be applicable to liquid rocket combustors was designed and tested. The characteristics of atomization and spray from a porous and a shear coaxial injector were characterized by the momentum flux ratio. The breakup mechanism of the porous injector is governed by Taylor-Culick flow and axial shear forces. Momentum of injected gas flow through a porous material which is composed of sintered metal is radically transferred to the center of the liquid column, and then liquid column is effectively broken up. Although the shapes of spray from porous and shear co- axial jets were similar for various momentum ratio, spray structures such as spray angle and droplet sizes were different. As increasing the momentum flux ratio, SMD from the porous injector showed smaller value than the shear coaxial injector展开更多
Randomness plays a major role in the interpretation of many interesting traffic flow phenomena,such as hysteresis,capacity drop and spontaneous breakdown. The analysis of the uncertainty and reliability of traffic sys...Randomness plays a major role in the interpretation of many interesting traffic flow phenomena,such as hysteresis,capacity drop and spontaneous breakdown. The analysis of the uncertainty and reliability of traffic systems is directly associated with their random characteristics. Therefore,it is beneficial to understand the distributional properties of traffic variables. This paper focuses on the dependence relation between traffic flow density and traffic speed,which constitute the fundamental diagram (FD). The traditional model of the FD is obtained essentially through curve fitting. We use the copula function as the basic toolkit and provide a novel approach for identifying the distributional patterns associated with the FD. In particular,we construct a rule-of-thumb nonparametric copula function,which in general avoids the mis-specification risk of parametric approaches and is more efficient in practice. By applying our construction to loop detector data on a freeway,we identify the dependence patterns existing in traffic data. We find that similar modes exist among traffic states of low,moderate or high traffic densities. Our findings also suggest that highway traffic speed and traffic flow density as a bivariate distribution is skewed and highly heterogeneous.展开更多
Dear Editor,Although simple sequence repeat（SSR）markers are not new,they are still useful and often used markers in molecular mapping and marker-assisted breeding,particularly in developing countries.However,locus-s...Dear Editor,Although simple sequence repeat（SSR）markers are not new,they are still useful and often used markers in molecular mapping and marker-assisted breeding,particularly in developing countries.However,locus-specific SSR markers could be more useful and informative in wheat breeding and genetic studies.In the present study,221,911 locus-specific SSR markers were designed.Verification of polymorphisms showed that the proportion of polymorphic markers increases with an increase in SSR size.展开更多
We present an efficient faithful multipartite polarization entanglement distribution protocol over an ar- bitrary noisy channel. The spatial degree of freedom is used to carry the entanglement during the transmission....We present an efficient faithful multipartite polarization entanglement distribution protocol over an ar- bitrary noisy channel. The spatial degree of freedom is used to carry the entanglement during the transmission. We describe the principle by distributing n-qubit Greenberge-Horne--Zeilinger state and n-qubit W state. Our scheme can be used to distribute arbitrary n-qUbit entangled states to n distant locations. The remote parties can obtain maximally entangled states deterministically on the polarization of photons. Only passive linear optics are employed in our setup, which makes our scheme more feasible and efficient for practical application in long distance quantum communication.展开更多
基金financial support from Zhang Zidao Sland Group Co.,Ltd. for the project (99801214)
文摘Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop （Patinopecten yessoensisis Jay, 1857） larval development stages. The aim of this study was to characterize and compare the bacterial communities associating with Yesso scallop larval development at fertilized egg S l, trochophora S2, D-shaped larvae S3, umbo larvae S4, and juvenile scallop S5 stages by Illumina high-throughput sequencing. Genomic DNA was extracted from the larvae and their associating baetera, and a gene segment covering V3-V4 region of 16S rRNA gene was amplified and sequenced using an Illumina Miseq sequencer. Overall, 106760 qualified sequences with an average length of 449 bp were obtained. Sequences were compared with those retrieved from 16S rRNA gene databases, and 4 phyla, 7 classes, 15 orders, 21 families, 31 genera were identified. Proteobacteria was predominant phylum, accounting for more than 99%, at all 5 larval development stages. At genus level, Pseudomonas was dominant at stages S1 （80.60%）, S2 （87.77%） and S5 （68.71%）, followed by Photobacterium （17.06%） and Aeromonas （1.64%） at stage S1, Serratia （6.94%）, Stenotrophomonas （3.08%） and Acinetobacter （1.2%） at stage S2, Shewanella （25.95%） and Pseudoalteromonas （4.57%） at stage S5. Moreover, genus Pseudoal- teromonas became dominant at stages S3 （44.85%） and S4 （56.02%）, followed by Photobacterium （29.82%）, Pseudomonas （11.86%）, Aliivibrio （8.60%） and Shewanella （3.39%） at stage S3, Pseudomonas （18.16%）, Aliivibrio （14.29%）, Shewanella （4.11%）, Psychro- monas （4.04%） and Psychrobacter （1.81%） at stage S4. From the results, we concluded that the bacterial community changed sig- nificantly at different development stages of Yesso Scallop larvae.
文摘The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decrease sharply from Hangzhou Bay to the offshore area. Suspended sediment transport is mainly controlled by advection transport and gravitational circulation transport. The settling velocity of suspended sediments gradually decreases from Hangzhou Bay to the offshore area. The settlement of suspended sediments mainly takes place during the turning phase of the tidal currents.
文摘This paper proposed that the flow characteristic of electronic expansion valve should be adapted to the evaporator superheat gain to refrigerant flow rate under different working conditions. Two native methods of geometry modeling of electronic expansion valve head were introduced. By analysis of them, some shortcoming was detected and a universal modeling method of electronic expansion valve head was put forward. Through this model, the flow characteristic of EEV and the influence factors can be investigated more deeply.
基金Supported by the National Natural Science Foundation of China （51075001） the Nature Science Research Project of Anhui Province （KJ2009A020）
文摘Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows： during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool＇s displacement of the safety valve, and it can be used to control the high-flow three-way valve＇s sensitivity.
文摘Because of the difficulties of describing the process of combustion of underground mine fires, usually the fire seat is considered as a fixed point in the methods of mine fire computer simulation, however this is not in keeping with the feature of the distribution of the combustibles and the process of combustion in mine fires. A conception about movable linear fire seat is put forward first by the authors, together with the calculated models of the thermal decomposition rate, flame spreading velocity and the steady burning length of a linear fire seat etc. The paper also introduces the results of the application of these models.
基金supported by the National Natural Science Foundation of China under Grant No.21307160the Natural Science Foundation of Shandong Province under Grant No.ZR2013EEQ030the Fundamental Research Funds for the Central Universities under Grant No.R1404005A
文摘The denitrifying sulfide removal(DSR) process has recently been studied extensively from an engineering perspective. However, the importance of microbial communities of this process was generally underestimated. In this study, the microbial community structure of a lab-scale DSR reactor was characterized in order to provide a comprehensive insight into the key microbial groups in DSR system. Results from high-throughput sequencing analysis revealed that the fraction of autotrophic denitrifiers increased from 2.34 % to 10.93% and 44.51% in the DSR system when the influent Na Cl increased from 0 g/L, to 4 g/L and 30 g/L, respectively. On the contrary, the fraction of heterotrophic denitrifiers decreased from 61.74% to 39.57%, and 24.12%, respectively. Azoarcus and Thiobacillus were the main autotrophic denitrifiers, and Thauera was the main hetetrophic denitrifier during the whole process. This study could be useful for better understanding the interaction between autotrophs and heterotrophs in DSR system.
基金supported by National Basic Research Program of China (Grant No. 2009CB421405)National Natural Science Foundation of China (Grant No. 40730952)Open Fund of Regional Climate-Environment Research for Temperate East Asia,Chinese Academy of Sciences
文摘This study evaluates the spatial distributions in the quality of momentum and sensible heat fluxes,and determines the turbulent transfer characteristics with quality-controlled observations.The research is based on raw turbulence data collected over a Gobi surface in the Dunhuang area in June 2004.The results indicate that part of the momentum fluxes are of poor quality in the daytime and nighttime.The poor quality of the momentum fluxes in the daytime is mainly attributed to the development of turbulence.The footprint reveals that,in general,the momentum fluxes and sensible heat fluxes can be measured well in the east and west upwind sectors under unstable conditions.The relationship between the non-dimensional standard deviation of the wind components and atmospheric stability follow the "1/3 power law",which supports the Monin-Obukhov similarity theory.Moreover,this study identifies a clear disturbance in the measurements surrounding the Gobi surface.The momentum roughness length of z0m=0.59 mm is determined after excluding such disturbance,and the additional resistance during the daytime is proposed to be an average of 3.1,although its actual value is highly scattered.This study discusses the applicability of several thermodynamic parameterization schemes for the Gobi surface.The results show that the scheme κB-1=3.1 can represent well the summer diurnal turbulent heat transfer.
基金The National Basic Research Program of China("973"Project)(Grant No.2013CB035905)The National Natural Science Foundation of China(Grant No.51179114)
文摘The free flow on the step surfaces has received much attention for its representative body type,flow structure,water-air two phase flow,cavitation,and many complex issues.The experiments about the time-averaged pressure and aeration concentration distribution on the step surface show that the vertical plane of steps will inevitably experience negative pressure,which must rely on adequate aeration concentration to avoid cavitation damage.However,the self-aerated flow at the head section has a relatively low aeration concentration,and the concentration of the entire steps decreases with the increasing of weir head,the minimum appears in the vicinity of the corner,and the location is close to the minimum pressure.Thus,it is necessary to set aerator in the upstream end of the step surfaces to avoid cavitation damage.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean Government(MEST)(NRF-2011-0015435 and NRF-2012M 1A3A3A02033146)
文摘Spray structure and atomization characteristics were investigated through a comparison of a porous and a shear coaxial injector. The porous injector shows better atomization performance than the shear coaxial injector. To in- crease atomization performance and mixing efficiency of two-phase jets, a coaxial porous injector which can be applicable to liquid rocket combustors was designed and tested. The characteristics of atomization and spray from a porous and a shear coaxial injector were characterized by the momentum flux ratio. The breakup mechanism of the porous injector is governed by Taylor-Culick flow and axial shear forces. Momentum of injected gas flow through a porous material which is composed of sintered metal is radically transferred to the center of the liquid column, and then liquid column is effectively broken up. Although the shapes of spray from porous and shear co- axial jets were similar for various momentum ratio, spray structures such as spray angle and droplet sizes were different. As increasing the momentum flux ratio, SMD from the porous injector showed smaller value than the shear coaxial injector
基金Project (No. 50809058) supported by the National Natural Science Foundation of China
文摘Randomness plays a major role in the interpretation of many interesting traffic flow phenomena,such as hysteresis,capacity drop and spontaneous breakdown. The analysis of the uncertainty and reliability of traffic systems is directly associated with their random characteristics. Therefore,it is beneficial to understand the distributional properties of traffic variables. This paper focuses on the dependence relation between traffic flow density and traffic speed,which constitute the fundamental diagram (FD). The traditional model of the FD is obtained essentially through curve fitting. We use the copula function as the basic toolkit and provide a novel approach for identifying the distributional patterns associated with the FD. In particular,we construct a rule-of-thumb nonparametric copula function,which in general avoids the mis-specification risk of parametric approaches and is more efficient in practice. By applying our construction to loop detector data on a freeway,we identify the dependence patterns existing in traffic data. We find that similar modes exist among traffic states of low,moderate or high traffic densities. Our findings also suggest that highway traffic speed and traffic flow density as a bivariate distribution is skewed and highly heterogeneous.
基金supported by the National Natural Science Foundation of China(31270704,31600997)the Yangzhou Key Research and Development Program(YZ2016035)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Dear Editor,Although simple sequence repeat（SSR）markers are not new,they are still useful and often used markers in molecular mapping and marker-assisted breeding,particularly in developing countries.However,locus-specific SSR markers could be more useful and informative in wheat breeding and genetic studies.In the present study,221,911 locus-specific SSR markers were designed.Verification of polymorphisms showed that the proportion of polymorphic markers increases with an increase in SSR size.
基金Supported by the National Natural Science Foundation of China under Grant No.11004258Fundamental Research Funds for the Central Universities under Grant No.CQDXWL-2012-014
文摘We present an efficient faithful multipartite polarization entanglement distribution protocol over an ar- bitrary noisy channel. The spatial degree of freedom is used to carry the entanglement during the transmission. We describe the principle by distributing n-qubit Greenberge-Horne--Zeilinger state and n-qubit W state. Our scheme can be used to distribute arbitrary n-qUbit entangled states to n distant locations. The remote parties can obtain maximally entangled states deterministically on the polarization of photons. Only passive linear optics are employed in our setup, which makes our scheme more feasible and efficient for practical application in long distance quantum communication.
