To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve...To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve the system efficiency. The expander and the compressor are connected to the same shaft and integrated into one unit, with the latter being driven by the former, thus the transfer loss and leakage loss can be decreased greatly. In these systems, the expander can be either connected with the first stage compressor (shortened as DCDL cycle) or the second stage compressor (shortened as DCDH cycle), but the two configuration ways can get different performances. By setting up theoretical model for two kinds of expander configuration ways in the transcritical carbon dioxide two-stage compression cycle, the first and the second laws of thermodynamics are used to analyze the coefficient of performance, exergy efficiency, inter-stage pressure, discharge temperature and exergy losses of each component for the two cycles. From the model results, the performance of DCDH cycle is better than that of DCDL cycle. The analysis results are indispensable to providing a theoretical basis for practical design and operating.展开更多
In this paper both processes of landslide and subsidence are considered to be limited systems. Each of these systems in nature might be regarded as an organism. Generally their lifespan must develop with common ecolog...In this paper both processes of landslide and subsidence are considered to be limited systems. Each of these systems in nature might be regarded as an organism. Generally their lifespan must develop with common ecological characteristics, including several evolutional stages, such as initiation, growth, maturation, decline and death. Among these stages, maturation is emphasized so as to find the occurring or thriving date of both systems. An once-through cycle of both landslide and subsidence is established and is accurately predicted by a developed, mathematic model of the Poisson cycle. The Weibull distribution is cited for a landslide example. Both fundamentals are discussed. Stage predictions of landslide and subsidence are performed for several examples. Back analysis of landslides that have already happened are studied with the same model. And when compared with results from the biological mathematic model and with practical results, it is found that they correspond. Stage prediction of subsidences is also researched by the principle of the Poisson cycle.展开更多
The resistance torque of a piston stage II com- pressor generates strenuous fluctuations in a rotational period, and this can lead to negative influences on the working performance of the compressor. To restrain the s...The resistance torque of a piston stage II com- pressor generates strenuous fluctuations in a rotational period, and this can lead to negative influences on the working performance of the compressor. To restrain the strenuous fluctuations in the piston stage II compressor, a variable duty-cycle control method based on the resistance torque is proposed. A dynamic model of a stage II com- pressor is set up, and the resistance torque and other characteristic parameters are acquired as the control tar- gets. Then, a variable duty-cycle control method is applied to track the resistance torque, thereby improving the working performance of the compressor. Simulated results show that the compressor, driven by the proposed method, requires lower current, while the rotating speed and the output torque remain comparable to the traditional vari- able-frequency control methods. A variable duty-cycle control system is developed, and the experimental results prove that the proposed method can help reduce the specific power, input power, and working noise of the compressor to 0.97 kW.m-3.min-1, 0.09 kW and 3.10 dB, respectively, under the same conditions of discharge pressure of 2.00 MPa and a discharge volume of 0.095 m3/rain. The proposed variable duty-cycle control method tracks the resistance torque dynamically, and improves the working performance of a Stage II Compressor. The pro- posed variable duty-cycle control method can be applied to other compressors, and can provide theoretical guidance for the compressor.展开更多
Oceanic plateaus are large igneous provinces in the oceans,created by massive underwater eruptions,but their late-stage volcanism is poorly understood.With the addition of recent high-quality bathymetric data to exist...Oceanic plateaus are large igneous provinces in the oceans,created by massive underwater eruptions,but their late-stage volcanism is poorly understood.With the addition of recent high-quality bathymetric data to existing data,286 secondary cones were discovered over Shatsky Rise oceanic plateau.These cones with steeper flank slopes(mean 6.1°±4.4°)and smaller sizes(102–1923 m in height)are morphologically distinct from the plateau,and they are thought to have formed after the main volcanic episodes.Cone height and characteristic height(420 m)are close to seamounts in the Pacific Ocean,whereas greater than those in the Atlantic Ocean.Mean flatness of Shatsky Rise’s cones(0.25±0.20)are similar to that of seamounts in both Pacific and Atlantic Oceans,but notably density in cone distribution(0.56 km^-3)and their mean slope are significantly lower than those of seamounts in the two oceans.Lower slopes of secondary cones within Shatsky Rise may be explained by higher effusion rates of remaining magma.Although cone formation was expected to have a link to rifting by seafloor spreading,weak relationship between cone orientation and magnetic anomaly pattern implies that the expectation is negative.Moreover,weak correlation between the cone height and depth indicates it is not true that volcanic cones grow taller when they occur closer to the massif summits with thicker oceanic crust,which was suggested as the increase in hydraulic pressure.Cone height and flatness are also not strongly related,implying that remaining magma supply was too limited to foster the cones to critical height.展开更多
There are widespread Mesozoic–Cenozoic terrestrial volcanic activities in East China,and they produced favorable geologic factors for the volcanic reservoirs.To reveal the spatio-temporal evolution of regional volcan...There are widespread Mesozoic–Cenozoic terrestrial volcanic activities in East China,and they produced favorable geologic factors for the volcanic reservoirs.To reveal the spatio-temporal evolution of regional volcanisms and their tectonic setting,we subdivide Mesozoic–Cenozoic volcanic activities into 6 volcanic cycles(Ⅰ–Ⅵ),and summarize the temporal-spatial distribution,rock association and tectonic setting of each cycle.The Cycle I forms a post-orogenic intraplate bimodal volcanic association.The cyclesⅡandⅢinclude arc volcanic associations formed in compressional and extensional subduction environments,respectively.The CycleⅣcontains a post-orogenic arc bimodal association.The CycleⅤis a basaltic association of tholeiite series under initial rift setting,and the CycleⅥis basaltic association of alkaline series under typical rift setting.The volcanic strata between each cycle are bounded by regional unconformity.The above 6 volcanic cycles correspond to 6 sequential stages of tectonic evolutions from the Early Jurassic post-orogeny,the Mid-Jurassic–Cretaceous subduction of the paleo-Pacific Plate to the Cenozoic marginal rifting.According to the geological characteristics of volcanic reservoirs in different volcanic cycles,it is put forward that the CycleⅤis the major formation period of volcanic reservoirs in East China and should be the focus of exploration,and that the volcanic reservoirs of the CycleⅣare also worthy of attention.展开更多
Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth’s inner core is concerned, the Galactic Year may change the gravitational constant G...Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth’s inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core-mantle boundary (CMB) to crust. When the earth’s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.展开更多
<span lang="EN-US" style="font-family:;" "="">The domestic cat has been used as a model to carry out comparative research in assisted reproduction, to be applied in wild cats. ...<span lang="EN-US" style="font-family:;" "="">The domestic cat has been used as a model to carry out comparative research in assisted reproduction, to be applied in wild cats. The efficiency in domestic cat IVM concerning </span><span lang="EN-US" style="font-family:;" "="">the </span><span lang="EN-US" style="font-family:;" "="">reproductive status and/or cultivation times has previously been investigated;however, the studies were carried out separately. The objective of this research was to evaluate the maturation of oocytes of domestic cats of different reproductive stages using two different <i>in vitro </i>culture times. The ovaries were obtained by Ooforo-Salpingo-Hysterectomy of cats that were of the following groups: 1) prepubertal, 2) follicular, 3) pregnant or 4) in anestrus. Maturation was carried out with TCM199 medium supplemented with BSA for 24 h and 48 h. On average, 29 ± 25, 20 ± 15, 17 ± 9 and 17 ± 13 oocytes/cat were recovered from the prepubertal follicular, pregnant</span><span lang="EN-US" style="font-family:;" "="">,</span><span lang="EN-US" style="font-family:;" "=""> and anestrus stages, respectively, but did not show a significant difference (<i>P</i></span><span lang="EN-US" style="font-family:;" "=""> ></span><span lang="EN-US"> </span><span lang="EN-US" style="font-family:;" "="">0.05). Also, meiotic maturation did not show a significant difference between the different reproductive stages at 24 h and 48 h, respectively (<i>P</i> > 0.05). However, in the prepubertal and follicular stages, greater oocyte maturation numbers were observed at 48 h compared to 24 h (<i>P</i> < 0.05). In contrast, the aforementioned </span><span lang="EN-US" style="font-family:;" "="">result </span><span lang="EN-US" style="font-family:;" "="">was not observed in the pregnant and anestrus stages (<i>P</i> > 0.05), indicating that the <i>in vitro </i>culture duration is an important factor during <i>in vitro</i> maturation of domestic cat oocytes.</span>展开更多
文摘To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve the system efficiency. The expander and the compressor are connected to the same shaft and integrated into one unit, with the latter being driven by the former, thus the transfer loss and leakage loss can be decreased greatly. In these systems, the expander can be either connected with the first stage compressor (shortened as DCDL cycle) or the second stage compressor (shortened as DCDH cycle), but the two configuration ways can get different performances. By setting up theoretical model for two kinds of expander configuration ways in the transcritical carbon dioxide two-stage compression cycle, the first and the second laws of thermodynamics are used to analyze the coefficient of performance, exergy efficiency, inter-stage pressure, discharge temperature and exergy losses of each component for the two cycles. From the model results, the performance of DCDH cycle is better than that of DCDL cycle. The analysis results are indispensable to providing a theoretical basis for practical design and operating.
基金The paper is one part of a project supported by National Education Committee Funds for Doctoral Faculty
文摘In this paper both processes of landslide and subsidence are considered to be limited systems. Each of these systems in nature might be regarded as an organism. Generally their lifespan must develop with common ecological characteristics, including several evolutional stages, such as initiation, growth, maturation, decline and death. Among these stages, maturation is emphasized so as to find the occurring or thriving date of both systems. An once-through cycle of both landslide and subsidence is established and is accurately predicted by a developed, mathematic model of the Poisson cycle. The Weibull distribution is cited for a landslide example. Both fundamentals are discussed. Stage predictions of landslide and subsidence are performed for several examples. Back analysis of landslides that have already happened are studied with the same model. And when compared with results from the biological mathematic model and with practical results, it is found that they correspond. Stage prediction of subsidences is also researched by the principle of the Poisson cycle.
基金Supported by National Natural Science Foundation of China(Grant No.51275452)Zhejiang Provincical Natural Science Foundation of China(Grant No.LY14E050021)Commonweal Technology Project of Science and Technology Department of Zhejiang Province,China(Grant No.2015C31071)
文摘The resistance torque of a piston stage II com- pressor generates strenuous fluctuations in a rotational period, and this can lead to negative influences on the working performance of the compressor. To restrain the strenuous fluctuations in the piston stage II compressor, a variable duty-cycle control method based on the resistance torque is proposed. A dynamic model of a stage II com- pressor is set up, and the resistance torque and other characteristic parameters are acquired as the control tar- gets. Then, a variable duty-cycle control method is applied to track the resistance torque, thereby improving the working performance of the compressor. Simulated results show that the compressor, driven by the proposed method, requires lower current, while the rotating speed and the output torque remain comparable to the traditional vari- able-frequency control methods. A variable duty-cycle control system is developed, and the experimental results prove that the proposed method can help reduce the specific power, input power, and working noise of the compressor to 0.97 kW.m-3.min-1, 0.09 kW and 3.10 dB, respectively, under the same conditions of discharge pressure of 2.00 MPa and a discharge volume of 0.095 m3/rain. The proposed variable duty-cycle control method tracks the resistance torque dynamically, and improves the working performance of a Stage II Compressor. The pro- posed variable duty-cycle control method can be applied to other compressors, and can provide theoretical guidance for the compressor.
基金supported by the National Key R&D Program of China (No. 2018YFC0309800)the National Natural Science Foundation of China (Nos. 91628301, U1606401, 41606069, 41776058)+2 种基金the Natural Science Foundation of Guangdong Province in China (No. 2017A030313243)the Chinese Academy of Sciences (Nos. Y4SL021001, QYZDY-SSWDQC005)the China Association of Marine Affairs (No. CAMAZD201714)
文摘Oceanic plateaus are large igneous provinces in the oceans,created by massive underwater eruptions,but their late-stage volcanism is poorly understood.With the addition of recent high-quality bathymetric data to existing data,286 secondary cones were discovered over Shatsky Rise oceanic plateau.These cones with steeper flank slopes(mean 6.1°±4.4°)and smaller sizes(102–1923 m in height)are morphologically distinct from the plateau,and they are thought to have formed after the main volcanic episodes.Cone height and characteristic height(420 m)are close to seamounts in the Pacific Ocean,whereas greater than those in the Atlantic Ocean.Mean flatness of Shatsky Rise’s cones(0.25±0.20)are similar to that of seamounts in both Pacific and Atlantic Oceans,but notably density in cone distribution(0.56 km^-3)and their mean slope are significantly lower than those of seamounts in the two oceans.Lower slopes of secondary cones within Shatsky Rise may be explained by higher effusion rates of remaining magma.Although cone formation was expected to have a link to rifting by seafloor spreading,weak relationship between cone orientation and magnetic anomaly pattern implies that the expectation is negative.Moreover,weak correlation between the cone height and depth indicates it is not true that volcanic cones grow taller when they occur closer to the massif summits with thicker oceanic crust,which was suggested as the increase in hydraulic pressure.Cone height and flatness are also not strongly related,implying that remaining magma supply was too limited to foster the cones to critical height.
基金supported by the State Key R&D Project of the Ministry of Science and Technology of China(No.2016YFC06002010).
文摘There are widespread Mesozoic–Cenozoic terrestrial volcanic activities in East China,and they produced favorable geologic factors for the volcanic reservoirs.To reveal the spatio-temporal evolution of regional volcanisms and their tectonic setting,we subdivide Mesozoic–Cenozoic volcanic activities into 6 volcanic cycles(Ⅰ–Ⅵ),and summarize the temporal-spatial distribution,rock association and tectonic setting of each cycle.The Cycle I forms a post-orogenic intraplate bimodal volcanic association.The cyclesⅡandⅢinclude arc volcanic associations formed in compressional and extensional subduction environments,respectively.The CycleⅣcontains a post-orogenic arc bimodal association.The CycleⅤis a basaltic association of tholeiite series under initial rift setting,and the CycleⅥis basaltic association of alkaline series under typical rift setting.The volcanic strata between each cycle are bounded by regional unconformity.The above 6 volcanic cycles correspond to 6 sequential stages of tectonic evolutions from the Early Jurassic post-orogeny,the Mid-Jurassic–Cretaceous subduction of the paleo-Pacific Plate to the Cenozoic marginal rifting.According to the geological characteristics of volcanic reservoirs in different volcanic cycles,it is put forward that the CycleⅤis the major formation period of volcanic reservoirs in East China and should be the focus of exploration,and that the volcanic reservoirs of the CycleⅣare also worthy of attention.
基金the part of the research fruit of the project(No.49774228)supported by National Natural Science Foundation of China.
文摘Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth’s inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core-mantle boundary (CMB) to crust. When the earth’s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.
文摘<span lang="EN-US" style="font-family:;" "="">The domestic cat has been used as a model to carry out comparative research in assisted reproduction, to be applied in wild cats. The efficiency in domestic cat IVM concerning </span><span lang="EN-US" style="font-family:;" "="">the </span><span lang="EN-US" style="font-family:;" "="">reproductive status and/or cultivation times has previously been investigated;however, the studies were carried out separately. The objective of this research was to evaluate the maturation of oocytes of domestic cats of different reproductive stages using two different <i>in vitro </i>culture times. The ovaries were obtained by Ooforo-Salpingo-Hysterectomy of cats that were of the following groups: 1) prepubertal, 2) follicular, 3) pregnant or 4) in anestrus. Maturation was carried out with TCM199 medium supplemented with BSA for 24 h and 48 h. On average, 29 ± 25, 20 ± 15, 17 ± 9 and 17 ± 13 oocytes/cat were recovered from the prepubertal follicular, pregnant</span><span lang="EN-US" style="font-family:;" "="">,</span><span lang="EN-US" style="font-family:;" "=""> and anestrus stages, respectively, but did not show a significant difference (<i>P</i></span><span lang="EN-US" style="font-family:;" "=""> ></span><span lang="EN-US"> </span><span lang="EN-US" style="font-family:;" "="">0.05). Also, meiotic maturation did not show a significant difference between the different reproductive stages at 24 h and 48 h, respectively (<i>P</i> > 0.05). However, in the prepubertal and follicular stages, greater oocyte maturation numbers were observed at 48 h compared to 24 h (<i>P</i> < 0.05). In contrast, the aforementioned </span><span lang="EN-US" style="font-family:;" "="">result </span><span lang="EN-US" style="font-family:;" "="">was not observed in the pregnant and anestrus stages (<i>P</i> > 0.05), indicating that the <i>in vitro </i>culture duration is an important factor during <i>in vitro</i> maturation of domestic cat oocytes.</span>