Sealing performance of the reciprocating seals on a larger diameter (100 mmin diameter) axial piston is theoretically investigated. Based on the characteristics of theclearance flow between the seal and the piston, re...Sealing performance of the reciprocating seals on a larger diameter (100 mmin diameter) axial piston is theoretically investigated. Based on the characteristics of theclearance flow between the seal and the piston, reasonable boundary conditions for Navier-Stokesequations are determined and the equations are modified, so that the final equations can describethe real flow state of the clearance flow. Through combining the final equations with finite elementmethod, the pressure distributions within the clearance field during the reciprocating motion ofthe piston and the leakage rate with the pressure are studied. The deflections of the seal whichaffect sealing performance are calculated as well. Sealing performance of piston seals using oil asthe working liquid is compared with using water. It is concluded that the seal using water as theworking liquid is under dry friction, which cannot be dealt with the theory of fluid mechanics. Theseal structure is only acceptable using oil as the working liquid..展开更多
The Oligocene–Miocene carbonate record of the Zagros Mountains, known as the Asmari Formation, constitutes an important hydrocarbon reservoir in southern Iran. This marine carbonate succession, which developed under ...The Oligocene–Miocene carbonate record of the Zagros Mountains, known as the Asmari Formation, constitutes an important hydrocarbon reservoir in southern Iran. This marine carbonate succession, which developed under tropical conditions, is explored in terms of larger foraminiferal biostratigraphy, facies analysis and sequence stratigraphy in a new section at Papoon cropping out in the western Fars sub-basin, in the south-east of the Zagros belt. Facies analysis shows evidence of re-working and transport of skeletal components throughout the depositional system, interpreted here as a carbonate ramp. The foraminifera-based biozones identified include the Globigerina–Turborotalia cerroazulensis–Hantkenina Zone and Nummulites vascus–Nummulites fichteli Zone, both of Rupelian age, the Archaias asmaricus–Archaias hensoni–Miogypsinoides complanatus Zone of Chattian age and the ‘Indeterminate’ Zone of Aquitanian age. The vertical sedimentary evolution of the formation exhibits a progressive shallowing of the facies belts and thus the succession is interpreted as a high-rank low-order regressive systems tract. This long-lasting Rupelian–Aquitanian regressive event is in accordance with accepted global long-term eustatic curves. Accordingly, long-term eustatic trends would have been a factor controlling accommodation during the deposition of the Asmari Formation studied in the western Fars sub-basin.展开更多
The aim of this paper is to investigate the effects on Moon-Earth gravitational variations and Moon phases during three Solar Cycless (SC22, SC23, SC24). The first part defines gravitational forces as a force that cre...The aim of this paper is to investigate the effects on Moon-Earth gravitational variations and Moon phases during three Solar Cycless (SC22, SC23, SC24). The first part defines gravitational forces as a force that creates an oscillation when the moon is reaching the Perigee, the smallest distance between the Moon and Earth during its rotational movement around Earth. It has a small amplitude and large period. Unlikely other authors, we do not find a direct connection between the Moon phases and big earthquakes worldwide. The study is performed through the three Solar Cycless, which refers to the variation in the Sun’s magnetic field. However, a strong indication appeared that almost the totality of the largest quakes studied happened preferentially at the subduction zones, in the Southern Hemisphere. In this research we apply experimental data to find the tide force, and the Perigee position is an experimental value. Other parameters are experimental, such as the length of Solar Cycless, the Moon’s phases connected to each earthquake where M ≥ 7.5. The calculations use regression in time to find the results. Our model considers in the regression the period 1986-2018.展开更多
Objective:Robot-assisted partial nephrectomy(RAPN)has become widely used for treatment of renal cell carcinoma and it is expanding in the field of complex renal masses.The aim of this systematic review was to analyze ...Objective:Robot-assisted partial nephrectomy(RAPN)has become widely used for treatment of renal cell carcinoma and it is expanding in the field of complex renal masses.The aim of this systematic review was to analyze outcomes of RAPN for completely endophytic renal masses,large tumors(cT2-T3),renal cell carcinoma in solitary kidney,recurrent tumors,completely endophytic and hilar masses,and simultaneous and multiple tumors.Methods:A comprehensive search in the PubMed,Scopus,Web of Science,and Cochrane Central Register of Controlled Trials databases was performed in December 2022 for English language papers.The primary endpoint was to evaluate the role of RAPN in the setting of each category of complex renal masses considered.The secondary endpoint was to evaluate the surgical and functional outcomes.Results:After screening 1250 records,43 full-text manuscripts were selected,comprising over 8500 patients.Twelve and thirteen studies reported data for endophytic and hilar renal masses,respectively.Five and three studies reported outcomes for cT2-T3 and solitary kidney patients,respectively.Four studies focused on redo-RAPN for recurrent tumors.Two studies investigated simultaneous bilateral renal masses and five reports focused on multiple tumor excision in ipsilateral kidney.Conclusion:Over the past decade,evidence supporting the use of RAPN for the most challenging nephron-sparing surgery indications has continuously grown.Although limitations remain including study design and lack of detailed long-term functional and oncological outcomes,the adoption of RAPN for the included advanced indications is associated with favorable surgical outcomes with good preservation of renal function without compromising the oncological result.Certainly,a higher likelihood of complication might be expected when facing extremely challenging cases.However,none of these indications should be considered per se an exclusion criterion for performing RAPN.Ultimately,a risk-adapted approach should be employed.展开更多
As a substitute for synthetic ammonia under mild condition, electrocatalytic nitrogen reduction reaction(NRR) provides a hopeful approach for the development of ammonia. Nevertheless, the current development of NRR el...As a substitute for synthetic ammonia under mild condition, electrocatalytic nitrogen reduction reaction(NRR) provides a hopeful approach for the development of ammonia. Nevertheless, the current development of NRR electrocatalysts is far from enough and a systematic research is needed to gain a better improvement. This article presents that 2 D C_(3)N_(4)-NV with a large specific surface area and abundant nitrogen vacancies is prepared by a simple and feasible method, and used as a metal-free catalyst for electrocatalytic NRR. Experiment result and density functional theory(DFT) calculation reveal that nitrogen vacancies in 2 D C_(3)N_(4)-NV can act as an efficient active site for catalytic NRR, which is conducive to capturing and activating N_(2), lowering Gibbs free energy(DG) in reaction and inhibiting hydrogen evolution reaction(HER) at the same time. In addition, the larger specific surface area also makes more active site exposed, which is good for the contact between the electrolyte and the active site, thus enhancing its NRR activity. The electrocatalyst shows an excellent catalytic activity for NRR in 0.1 M HCl, including Faradaic efficiency of 10.96%, NH_(3) yields of 17.85 lg h^(-1) mg_(cat)^(-1)., and good stability(over 20 h).展开更多
For an electron-electron collision with characteristic scale length larger than the relative gyro-radius of the two colliding electrons, when the initial relative parallel kinetic energy cannot surmount the Coulomb re...For an electron-electron collision with characteristic scale length larger than the relative gyro-radius of the two colliding electrons, when the initial relative parallel kinetic energy cannot surmount the Coulomb repulsive potential, reflection will occur with interchange of the parallel velocities of the two electrons after the collision. The Fokker–Planck approach is employed to derive the electron collision term C_R describing parallel velocity scattering due to the reflections for a magnetized plasma where the average electron gyro-radius is much smaller than the Debye length but much larger than the Landau length. The electron parallel velocity friction and diffusion coefficients due to the reflections are evaluated, which are found not to depend on the electron perpendicular velocity. By studying the temporal evolution of the H quantity due to CR, it is found that C_R eventually makes the system relax to a state in which the electron parallel velocity distribution is decoupled from the perpendicular velocity distribution.展开更多
A novel transit-time oscillator(TTO)is proposed in this paper.An axial cathode which has been widely used in high power microwave(HPM)source and an extractor with radial feature are adopted.In this way,the inherent ad...A novel transit-time oscillator(TTO)is proposed in this paper.An axial cathode which has been widely used in high power microwave(HPM)source and an extractor with radial feature are adopted.In this way,the inherent advantages of axial and radial TTO,both of which can be utilized as high-quality intense relativistic electron beam(IREB),can be generated and the power capacity is also increased.The working mode isπ/2 mode of TM01 based on small-signal theory,and under the same energy storage,the maximum electric field in extractor decreases 16.3%.Besides,by utilizing the natural bending of the solenoid,this TTO saves over 60%of the length required by the uniform magnetic field,and consequently reduces the energy consumed by solenoid.The PIC simulation shows that by using 1.0-T decreasing magnetic field generated by the shorter solenoid,3.37-GW microwave at 12.43 GHz is generated with 620-kV and 13.27-kA input,and the overall conversion efficiency is 41%.展开更多
The main purpose of this paper is the sequence stratigraphy and biostratigraphy of lower Tertiary sediments on the base of larger benthic foraminifera in northeast of Iran (Chehel-Kaman Formation). This formation main...The main purpose of this paper is the sequence stratigraphy and biostratigraphy of lower Tertiary sediments on the base of larger benthic foraminifera in northeast of Iran (Chehel-Kaman Formation). This formation mainly consists of Limestone, dolomite and interbeds of sand, shale and evaporate sediments. Petrographical studies indicate that these sediments may have been deposited on a shallow carbonate platform ramp and consist of 4 carbonate lithofacies (15 subfacies). These lithofacies may have been deposited in open marine, shoal, lagoon and tidal flat environmental conditions. Sequence stratigraphy analysis led to identification of 4 third-order depositional sequences, bounded by type 2 (within the top of the underlying Pestehleigh Formation) and type 1 sequence boundaries (paleosol). Interpreted sea level curve in this basin can be relatively correlated with global curves during Paleocene time and a with a sea-level fall occurred in the latest Paleocene, followed by a rise in the earliest Eocene. Biostratigraphy study led to the identification of 32 larger benthic Foraminifera genera. The Paleocene/Eocene boundary has been probably recorded as a thin red paleosol horizon (~10 - 15 cm).展开更多
It is widely accepted that eye is a high-frequency word in English,and one of the stronger collocations is naked eye.In order to research the usage of naked eye,a concordance line of naked eye is selected from corpus ...It is widely accepted that eye is a high-frequency word in English,and one of the stronger collocations is naked eye.In order to research the usage of naked eye,a concordance line of naked eye is selected from corpus evidence.The collocation,meaning,attitude words and larger variable expression of naked eye are mainly examined with the purpose of better studying the usage of naked eye.展开更多
The shallow marine carbonates of the upper Oligocene Qom Formation yielded several occurrences of the foraminiferan genus Neoplanorbulinella Matsumaru. Neoplanorbulinella saipanensis Matsumaru has so far been recorded...The shallow marine carbonates of the upper Oligocene Qom Formation yielded several occurrences of the foraminiferan genus Neoplanorbulinella Matsumaru. Neoplanorbulinella saipanensis Matsumaru has so far been recorded from the late Eocene-early Miocene of Japan and late Oligocene of NE Italy whereas N. malatyaensis Gedik is only reported from the Oligocene from its type locality in the Malatya Basin, eastern Turkey. The new records reported here from the Qom Formation indicate that both species occur in the Dobaradar section, ca. 10 km south of the city of Qom in North-Central Iran. The palaeogeographic distribution of these two species therefore has to be extended as far as the palaeolongitude of current Central Iran.The accompanying larger benthic foraminifers, including Miogypsinoides complanatus(Schlumberger),M. formosensis Yabe and Hanzawa, Spiroclypeus margaritatus(Schlumberger), Operculina complanata(Defrance), and Risananeiza pustulosa Boukhary et al., indicate the upper Chattian SBZ 23 Zone. The coexistence of the N. saipanensis and N. malatyaensis points to suitable palaeobiogeographic conditions of Central Iran to host Western and Eastern Tethyan taxa.展开更多
Integer factorization (IFP), also called prime factorization, is an important problem in number theory, cryptography, and quantum computation. Factoring large integers to attack the RSA cryptosystem is intractable for...Integer factorization (IFP), also called prime factorization, is an important problem in number theory, cryptography, and quantum computation. Factoring large integers to attack the RSA cryptosystem is intractable for powerful supercomputers, let alone classical computers. In 1994, Shor [1]presented an algorithm that potentially enabled a quantum computer to find prime factors in polynomial time.展开更多
The Cenozoic larger foraminifera are important for biostratigraphy in SE Asia.This review examines the taxonomic inconsistencies of this group and especially the confusion over concepts of evolution,migration,radiatio...The Cenozoic larger foraminifera are important for biostratigraphy in SE Asia.This review examines the taxonomic inconsistencies of this group and especially the confusion over concepts of evolution,migration,radiation and extinction.It is proposed that from the Mediterranean to Indo-Pacific,Latest Eocene through Miocene,larger foraminifera populations were more homogenous than previously believed.Lineages show a slow morphological radiation interrupted by several extinctions.This pattern is superimposed on a long-term decline in larger foraminiferal abundance.The dating of the major biostratigraphic events are qualified.The main lineages of larger foraminifera can be classified by their evolutionary style.The classically“large”genera have highly peramorphic trends achieved through strong orthoselection,and these lineages were the most severely hit by a series of Mid-Eocene to Mid-Miocene extinction events.Other carbonate facies taxa that are traditionally grouped with the larger foraminifera are characterised by weak paramorphism,and these were much less affected by the extinction events.Some of these weakly peramorphic forms underwent Latest Miocene to recent radiation to and locally become rock-forming organisms.The three major and one minor larger foraminiferal extinction events since the Mid Eocene coincide with abrupt tectonic events across SE Asia.However,there are probably multiple causes for these extinctions,including global climatic changes.展开更多
Symmetric alternating directionmethod of multipliers(ADMM)is an efficient method for solving a class of separable convex optimization problems.This method updates the Lagrange multiplier twice with appropriate step si...Symmetric alternating directionmethod of multipliers(ADMM)is an efficient method for solving a class of separable convex optimization problems.This method updates the Lagrange multiplier twice with appropriate step sizes at each iteration.However,such step sizes were conservatively shrunk to guarantee the convergence in recent studies.In this paper,we are devoted to seeking larger step sizes whenever possible.The logarithmic-quadratic proximal(LQP)terms are applied to regularize the symmetric ADMM subproblems,allowing the constrained subproblems to then be converted to easier unconstrained ones.Theoretically,we prove the global convergence of such LQP-based symmetric ADMM by specifying a larger step size domain.Moreover,the numerical results on a traffic equilibrium problem are reported to demonstrate the advantage of the method with larger step sizes.展开更多
Examples of evolution,extinction and homoplasy of the larger benthic foraminifera(LBF)occur throughout their history.Since the Carboniferous,LBF have thrived in carbonate-rich tropical and subtropical shallow-marine s...Examples of evolution,extinction and homoplasy of the larger benthic foraminifera(LBF)occur throughout their history.Since the Carboniferous,LBF have thrived in carbonate-rich tropical and subtropical shallow-marine shelf environments.Their high abundance and diversity are due primarily to their extraordinary ability to inhabit a range of ecological niches and by hosting a variety of symbionts.Attaining relatively large,centimetre-scale sizes,made some forms very specialized and vulnerable to rapid ecological changes.For this reason,some LBF have shown a tendency to suffer periodically during major extinctions,especially when environmental conditions have changed rapidly and/or substantially.This,however,makes them valuable biostratigraphic microfossils and,in addition,gives invaluable insight into the spatial and temporal process of biological evolution,such as convergent/homoplasy and homology/iterative evolution.Here the evolutionary behavior of two important morphological types that occurred throughout the history of the LBF are discussed,namely the planispiral-fusiform test as typified by the fusulinids in the Late Paleozoic and the alveolinids in the Mid-Cretaceous and Neogene,and the three-layered discoid lenticular test as characterized by the orbitoids in the Mid-to Late Cretaceous,the orthophragminids in the Paleogene,and lepidocyclinids in the Oligocene to Quaternary.Understanding the propensity of these forms to convergent and iterative evolution,with the repeated re-occurrence of certain morphological features,is essential in understanding and constructing their phylogenetic relationships more generally within the main groups of the LBF.The insights gained from the history of these LBF have wider implications,and provide a more general understanding of the impacts of climate and ecological changes as driving forces for biological evolution.展开更多
The grating fringe on the reference plane is broadened in the intersecting axis system because of oblique-angle projection. In order to solve this problem, we study the theoretical model of the temporal phase unwrappi...The grating fringe on the reference plane is broadened in the intersecting axis system because of oblique-angle projection. In order to solve this problem, we study the theoretical model of the temporal phase unwrapping method based on the fringe cycle correction. We also study the 3D shape measurement theoretical model of the larger complex objects after considering the coordinate deviation and lens distortion. Experimental results demonstrate that the fringe cycle on the reference plane can be corrected to a constant value, the lens distortion can be corrected, and 3D shape of larger complex objects can be accurately measured.展开更多
基金This project is supported by National Natural Science Foundation of China(No.50005019).
文摘Sealing performance of the reciprocating seals on a larger diameter (100 mmin diameter) axial piston is theoretically investigated. Based on the characteristics of theclearance flow between the seal and the piston, reasonable boundary conditions for Navier-Stokesequations are determined and the equations are modified, so that the final equations can describethe real flow state of the clearance flow. Through combining the final equations with finite elementmethod, the pressure distributions within the clearance field during the reciprocating motion ofthe piston and the leakage rate with the pressure are studied. The deflections of the seal whichaffect sealing performance are calculated as well. Sealing performance of piston seals using oil asthe working liquid is compared with using water. It is concluded that the seal using water as theworking liquid is under dry friction, which cannot be dealt with the theory of fluid mechanics. Theseal structure is only acceptable using oil as the working liquid..
基金supported by the I + D + i research project CGL201560805-P (BIOGEOEVENTS)the Grup de Recerca Reconegut per la Generalitat de Catalunya 2017 SGR 824 "Geologia Sedimentària"
文摘The Oligocene–Miocene carbonate record of the Zagros Mountains, known as the Asmari Formation, constitutes an important hydrocarbon reservoir in southern Iran. This marine carbonate succession, which developed under tropical conditions, is explored in terms of larger foraminiferal biostratigraphy, facies analysis and sequence stratigraphy in a new section at Papoon cropping out in the western Fars sub-basin, in the south-east of the Zagros belt. Facies analysis shows evidence of re-working and transport of skeletal components throughout the depositional system, interpreted here as a carbonate ramp. The foraminifera-based biozones identified include the Globigerina–Turborotalia cerroazulensis–Hantkenina Zone and Nummulites vascus–Nummulites fichteli Zone, both of Rupelian age, the Archaias asmaricus–Archaias hensoni–Miogypsinoides complanatus Zone of Chattian age and the ‘Indeterminate’ Zone of Aquitanian age. The vertical sedimentary evolution of the formation exhibits a progressive shallowing of the facies belts and thus the succession is interpreted as a high-rank low-order regressive systems tract. This long-lasting Rupelian–Aquitanian regressive event is in accordance with accepted global long-term eustatic curves. Accordingly, long-term eustatic trends would have been a factor controlling accommodation during the deposition of the Asmari Formation studied in the western Fars sub-basin.
文摘The aim of this paper is to investigate the effects on Moon-Earth gravitational variations and Moon phases during three Solar Cycless (SC22, SC23, SC24). The first part defines gravitational forces as a force that creates an oscillation when the moon is reaching the Perigee, the smallest distance between the Moon and Earth during its rotational movement around Earth. It has a small amplitude and large period. Unlikely other authors, we do not find a direct connection between the Moon phases and big earthquakes worldwide. The study is performed through the three Solar Cycless, which refers to the variation in the Sun’s magnetic field. However, a strong indication appeared that almost the totality of the largest quakes studied happened preferentially at the subduction zones, in the Southern Hemisphere. In this research we apply experimental data to find the tide force, and the Perigee position is an experimental value. Other parameters are experimental, such as the length of Solar Cycless, the Moon’s phases connected to each earthquake where M ≥ 7.5. The calculations use regression in time to find the results. Our model considers in the regression the period 1986-2018.
文摘Objective:Robot-assisted partial nephrectomy(RAPN)has become widely used for treatment of renal cell carcinoma and it is expanding in the field of complex renal masses.The aim of this systematic review was to analyze outcomes of RAPN for completely endophytic renal masses,large tumors(cT2-T3),renal cell carcinoma in solitary kidney,recurrent tumors,completely endophytic and hilar masses,and simultaneous and multiple tumors.Methods:A comprehensive search in the PubMed,Scopus,Web of Science,and Cochrane Central Register of Controlled Trials databases was performed in December 2022 for English language papers.The primary endpoint was to evaluate the role of RAPN in the setting of each category of complex renal masses considered.The secondary endpoint was to evaluate the surgical and functional outcomes.Results:After screening 1250 records,43 full-text manuscripts were selected,comprising over 8500 patients.Twelve and thirteen studies reported data for endophytic and hilar renal masses,respectively.Five and three studies reported outcomes for cT2-T3 and solitary kidney patients,respectively.Four studies focused on redo-RAPN for recurrent tumors.Two studies investigated simultaneous bilateral renal masses and five reports focused on multiple tumor excision in ipsilateral kidney.Conclusion:Over the past decade,evidence supporting the use of RAPN for the most challenging nephron-sparing surgery indications has continuously grown.Although limitations remain including study design and lack of detailed long-term functional and oncological outcomes,the adoption of RAPN for the included advanced indications is associated with favorable surgical outcomes with good preservation of renal function without compromising the oncological result.Certainly,a higher likelihood of complication might be expected when facing extremely challenging cases.However,none of these indications should be considered per se an exclusion criterion for performing RAPN.Ultimately,a risk-adapted approach should be employed.
基金funded by the National Natural Science Foundation of China (21802058 and 21872066)the Fundamental Research Funds for the Central Universities (China, lzujbky-2020-42)the Natural Science Foundation of Gansu Province (20JR5RA225)。
文摘As a substitute for synthetic ammonia under mild condition, electrocatalytic nitrogen reduction reaction(NRR) provides a hopeful approach for the development of ammonia. Nevertheless, the current development of NRR electrocatalysts is far from enough and a systematic research is needed to gain a better improvement. This article presents that 2 D C_(3)N_(4)-NV with a large specific surface area and abundant nitrogen vacancies is prepared by a simple and feasible method, and used as a metal-free catalyst for electrocatalytic NRR. Experiment result and density functional theory(DFT) calculation reveal that nitrogen vacancies in 2 D C_(3)N_(4)-NV can act as an efficient active site for catalytic NRR, which is conducive to capturing and activating N_(2), lowering Gibbs free energy(DG) in reaction and inhibiting hydrogen evolution reaction(HER) at the same time. In addition, the larger specific surface area also makes more active site exposed, which is good for the contact between the electrolyte and the active site, thus enhancing its NRR activity. The electrocatalyst shows an excellent catalytic activity for NRR in 0.1 M HCl, including Faradaic efficiency of 10.96%, NH_(3) yields of 17.85 lg h^(-1) mg_(cat)^(-1)., and good stability(over 20 h).
基金Supported by the National MCF Energy R&D Program under Grant No 2018YFE0311300the National Natural Science Foundation of China under Grant Nos 11875067,11835016,11705275,11675257 and 11675256+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB16010300the Key Research Program of Frontier Science of Chinese Academy of Sciences under Grant No QYZDJ-SSW-SYS016the External Cooperation Program of Chinese Academy of Sciences under Grant No 112111KYSB20160039
文摘For an electron-electron collision with characteristic scale length larger than the relative gyro-radius of the two colliding electrons, when the initial relative parallel kinetic energy cannot surmount the Coulomb repulsive potential, reflection will occur with interchange of the parallel velocities of the two electrons after the collision. The Fokker–Planck approach is employed to derive the electron collision term C_R describing parallel velocity scattering due to the reflections for a magnetized plasma where the average electron gyro-radius is much smaller than the Debye length but much larger than the Landau length. The electron parallel velocity friction and diffusion coefficients due to the reflections are evaluated, which are found not to depend on the electron perpendicular velocity. By studying the temporal evolution of the H quantity due to CR, it is found that C_R eventually makes the system relax to a state in which the electron parallel velocity distribution is decoupled from the perpendicular velocity distribution.
基金Project supported by the National Natural Science Foundation of China(Grant No.61701516)
文摘A novel transit-time oscillator(TTO)is proposed in this paper.An axial cathode which has been widely used in high power microwave(HPM)source and an extractor with radial feature are adopted.In this way,the inherent advantages of axial and radial TTO,both of which can be utilized as high-quality intense relativistic electron beam(IREB),can be generated and the power capacity is also increased.The working mode isπ/2 mode of TM01 based on small-signal theory,and under the same energy storage,the maximum electric field in extractor decreases 16.3%.Besides,by utilizing the natural bending of the solenoid,this TTO saves over 60%of the length required by the uniform magnetic field,and consequently reduces the energy consumed by solenoid.The PIC simulation shows that by using 1.0-T decreasing magnetic field generated by the shorter solenoid,3.37-GW microwave at 12.43 GHz is generated with 620-kV and 13.27-kA input,and the overall conversion efficiency is 41%.
文摘The main purpose of this paper is the sequence stratigraphy and biostratigraphy of lower Tertiary sediments on the base of larger benthic foraminifera in northeast of Iran (Chehel-Kaman Formation). This formation mainly consists of Limestone, dolomite and interbeds of sand, shale and evaporate sediments. Petrographical studies indicate that these sediments may have been deposited on a shallow carbonate platform ramp and consist of 4 carbonate lithofacies (15 subfacies). These lithofacies may have been deposited in open marine, shoal, lagoon and tidal flat environmental conditions. Sequence stratigraphy analysis led to identification of 4 third-order depositional sequences, bounded by type 2 (within the top of the underlying Pestehleigh Formation) and type 1 sequence boundaries (paleosol). Interpreted sea level curve in this basin can be relatively correlated with global curves during Paleocene time and a with a sea-level fall occurred in the latest Paleocene, followed by a rise in the earliest Eocene. Biostratigraphy study led to the identification of 32 larger benthic Foraminifera genera. The Paleocene/Eocene boundary has been probably recorded as a thin red paleosol horizon (~10 - 15 cm).
文摘It is widely accepted that eye is a high-frequency word in English,and one of the stronger collocations is naked eye.In order to research the usage of naked eye,a concordance line of naked eye is selected from corpus evidence.The collocation,meaning,attitude words and larger variable expression of naked eye are mainly examined with the purpose of better studying the usage of naked eye.
基金funded by Damghan University (Grant No. 653/19)。
文摘The shallow marine carbonates of the upper Oligocene Qom Formation yielded several occurrences of the foraminiferan genus Neoplanorbulinella Matsumaru. Neoplanorbulinella saipanensis Matsumaru has so far been recorded from the late Eocene-early Miocene of Japan and late Oligocene of NE Italy whereas N. malatyaensis Gedik is only reported from the Oligocene from its type locality in the Malatya Basin, eastern Turkey. The new records reported here from the Qom Formation indicate that both species occur in the Dobaradar section, ca. 10 km south of the city of Qom in North-Central Iran. The palaeogeographic distribution of these two species therefore has to be extended as far as the palaeolongitude of current Central Iran.The accompanying larger benthic foraminifers, including Miogypsinoides complanatus(Schlumberger),M. formosensis Yabe and Hanzawa, Spiroclypeus margaritatus(Schlumberger), Operculina complanata(Defrance), and Risananeiza pustulosa Boukhary et al., indicate the upper Chattian SBZ 23 Zone. The coexistence of the N. saipanensis and N. malatyaensis points to suitable palaeobiogeographic conditions of Central Iran to host Western and Eastern Tethyan taxa.
文摘Integer factorization (IFP), also called prime factorization, is an important problem in number theory, cryptography, and quantum computation. Factoring large integers to attack the RSA cryptosystem is intractable for powerful supercomputers, let alone classical computers. In 1994, Shor [1]presented an algorithm that potentially enabled a quantum computer to find prime factors in polynomial time.
基金supported by the National Natural Science Foundation of China(No.92055211)the China-ASEAN Maritime Cooperation Fund Project(No.12120100500017001).
文摘The Cenozoic larger foraminifera are important for biostratigraphy in SE Asia.This review examines the taxonomic inconsistencies of this group and especially the confusion over concepts of evolution,migration,radiation and extinction.It is proposed that from the Mediterranean to Indo-Pacific,Latest Eocene through Miocene,larger foraminifera populations were more homogenous than previously believed.Lineages show a slow morphological radiation interrupted by several extinctions.This pattern is superimposed on a long-term decline in larger foraminiferal abundance.The dating of the major biostratigraphic events are qualified.The main lineages of larger foraminifera can be classified by their evolutionary style.The classically“large”genera have highly peramorphic trends achieved through strong orthoselection,and these lineages were the most severely hit by a series of Mid-Eocene to Mid-Miocene extinction events.Other carbonate facies taxa that are traditionally grouped with the larger foraminifera are characterised by weak paramorphism,and these were much less affected by the extinction events.Some of these weakly peramorphic forms underwent Latest Miocene to recent radiation to and locally become rock-forming organisms.The three major and one minor larger foraminiferal extinction events since the Mid Eocene coincide with abrupt tectonic events across SE Asia.However,there are probably multiple causes for these extinctions,including global climatic changes.
基金This research was supported by National Natural Science Foundation of China Grant 11771078Natural Science Foundation of Jiangsu Province Grant BK20181258+1 种基金Project of 333 of Jiangsu Province Grant BRA2018351Postgraduate Research&Practice Innovation Program of Jiangsu Province Grant KYCX18_0200.
文摘Symmetric alternating directionmethod of multipliers(ADMM)is an efficient method for solving a class of separable convex optimization problems.This method updates the Lagrange multiplier twice with appropriate step sizes at each iteration.However,such step sizes were conservatively shrunk to guarantee the convergence in recent studies.In this paper,we are devoted to seeking larger step sizes whenever possible.The logarithmic-quadratic proximal(LQP)terms are applied to regularize the symmetric ADMM subproblems,allowing the constrained subproblems to then be converted to easier unconstrained ones.Theoretically,we prove the global convergence of such LQP-based symmetric ADMM by specifying a larger step size domain.Moreover,the numerical results on a traffic equilibrium problem are reported to demonstrate the advantage of the method with larger step sizes.
文摘Examples of evolution,extinction and homoplasy of the larger benthic foraminifera(LBF)occur throughout their history.Since the Carboniferous,LBF have thrived in carbonate-rich tropical and subtropical shallow-marine shelf environments.Their high abundance and diversity are due primarily to their extraordinary ability to inhabit a range of ecological niches and by hosting a variety of symbionts.Attaining relatively large,centimetre-scale sizes,made some forms very specialized and vulnerable to rapid ecological changes.For this reason,some LBF have shown a tendency to suffer periodically during major extinctions,especially when environmental conditions have changed rapidly and/or substantially.This,however,makes them valuable biostratigraphic microfossils and,in addition,gives invaluable insight into the spatial and temporal process of biological evolution,such as convergent/homoplasy and homology/iterative evolution.Here the evolutionary behavior of two important morphological types that occurred throughout the history of the LBF are discussed,namely the planispiral-fusiform test as typified by the fusulinids in the Late Paleozoic and the alveolinids in the Mid-Cretaceous and Neogene,and the three-layered discoid lenticular test as characterized by the orbitoids in the Mid-to Late Cretaceous,the orthophragminids in the Paleogene,and lepidocyclinids in the Oligocene to Quaternary.Understanding the propensity of these forms to convergent and iterative evolution,with the repeated re-occurrence of certain morphological features,is essential in understanding and constructing their phylogenetic relationships more generally within the main groups of the LBF.The insights gained from the history of these LBF have wider implications,and provide a more general understanding of the impacts of climate and ecological changes as driving forces for biological evolution.
基金supported by the National Natural Science Foundation of China(No.51365045)the Natural Science Foundation of Jiangxi Province(No.20122BAB202012)+1 种基金the Aviation Science Fund(No.2013ZE56013)the Education Department of Jiangxi Province(No.GJJ13522)
文摘The grating fringe on the reference plane is broadened in the intersecting axis system because of oblique-angle projection. In order to solve this problem, we study the theoretical model of the temporal phase unwrapping method based on the fringe cycle correction. We also study the 3D shape measurement theoretical model of the larger complex objects after considering the coordinate deviation and lens distortion. Experimental results demonstrate that the fringe cycle on the reference plane can be corrected to a constant value, the lens distortion can be corrected, and 3D shape of larger complex objects can be accurately measured.