Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devi...Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devices that can simultaneously obtain low off-state current(IOFF), high on-state current(ION) and steep subthreshold swing(SS). As a key element for the 2D/3D TFET, the intensive exploration of the tunnel diode based on the 2D/3D heterostructure is in urgent need.The transfer technique composed of the exfoliation and the release process is currently the most common approach to fabricating the 2D/3D heterostructures. However, the well-established transfer technique of the 2D materials is still unavailable.Only a small part of the irregular films can usually be obtained by mechanical exfoliation, while the choice of the chemical exfoliation may lead to the contamination of the 2D material films by the ions in the chemical etchants. Moreover, the deformation of the 2D material in the transfer process due to its soft nature also leads to the nonuniformity of the transferred film,which is one of the main reasons for the presence of the wrinkles and the stacks in the transferred film. Thus, the large-scale fabrication of the high-quality 2D/3D tunnel diodes is limited. In this article, a comprehensive transfer technique that can mend up the shortages mentioned above with the aid of the water and the thermal release tape(TRT) is proposed. Based on the method we proposed, the MoS_(2)/Si tunnel diode is experimentally demonstrated and the transferred monolayer MoS_(2) film with the relatively high crystal quality is confirmed by atomic force microscopy(AFM), scanning electron microscopy(SEM), and Raman characterizations. Besides, the prominent negative differential resistance(NDR) effect is observed at room temperature, which verifies the relatively high quality of the MoS_(2)/Si heterojunction. The bilayer MoS_(2)/Si tunnel diode is also experimentally fabricated by repeating the transfer process we proposed, followed by the specific analysis of the electrical characteristics. This study shows the advantages of the transfer technique we proposed and indicates the great application foreground of the fabricated 2D/3D heterostructure for ultralow-power tunneling devices.展开更多
This paper analyzes some specific features of the numerical interpretation of high-frequency electromagnetic logging data in vertical, deviated and horizontal boreholes entering oil- and water-saturated formations. Th...This paper analyzes some specific features of the numerical interpretation of high-frequency electromagnetic logging data in vertical, deviated and horizontal boreholes entering oil- and water-saturated formations. The interpretation is based on numerical modeling for signals.展开更多
Geometrical parameters of discontinuities,such as spacing,length,dip and fault throw between joints have a great influence on the mechanical behavior of jointed rock masses.Accurate characterization for discontinuitie...Geometrical parameters of discontinuities,such as spacing,length,dip and fault throw between joints have a great influence on the mechanical behavior of jointed rock masses.Accurate characterization for discontinuities is important for investigate the stability of rock masses.In this paper,the PFC2D is combined with joint network generation method to examine the mechanical behaviors of jointed mass.Taking Miaogou Open-pit Mine as an example,the information and statistical distributions of discontinuities of the slope rock masses are measured by ShapeMetriX3D measuring tool.Then,the automatic generation algorithm of random joints network based on the Monte-Carlo method is proposed using the programming language(FISH)embedded within PFC2D.This algorithm could represent the discontinuities compared with the geological surveys.In simulating the compression test of a jointed rock sample,the mechanical behavior and crack propagation were investigated.The results reveal that the failure mode and crack propagation of the jointed rock are dominated by the distribution of joints in addition to the intact rock properties.The simulation result shows the feasibility of the joints generating method in application to jointed rock mass.展开更多
There are great challenges for traditional three-dimensional( 3-D) interferometric inverse synthetic aperture radar( In ISAR) imaging algorithms of ship targets w ith 2-D sparsity in actual radar imaging system. To de...There are great challenges for traditional three-dimensional( 3-D) interferometric inverse synthetic aperture radar( In ISAR) imaging algorithms of ship targets w ith 2-D sparsity in actual radar imaging system. To deal w ith this problem,a novel 3-D In ISAR imaging method is proposed in this paper.First,the high-precision gradient adaptive algorithm w as adopted to reconstruct the echoes in range dimension. Then the method of minimizing the entropy of the average range profile w as applied to estimate the parameters w hich are used to compensate translation components of the received echoes. Besides,the phase adjustment and image coregistration of the sparse echoes w ere achieved at the same time through the approach of the joint phase autofocus. Finally,the 3-D geometry coordinates of the ship target w ith 2-D sparsity w ere reconstructed by combining the range measurement and interferometric processing of the ISAR images. Simulation experiments w ere carried out to verify the practicability and effectiveness of the algorithm in the case that the received echoes are in 2-D sparsity.展开更多
RNA structures are essential to support RNA functions and regulation in various biological processes. Recently, a range of novel technologies have been developed to decode genome-wide RNA structures and novel modes of...RNA structures are essential to support RNA functions and regulation in various biological processes. Recently, a range of novel technologies have been developed to decode genome-wide RNA structures and novel modes of functionality across a wide range of species. In this review, we summarize key strategies for probing the RNA structurome and discuss the pros and cons of representative technologies. In particular, these new technologies have been applied to dissect the structural landscape of the SARS-CoV-2 RNA genome. We also summarize the functionalities of RNA structures discovered in different regulatory layers-including RNA processing, transport, localization, and mRNA translation-across viruses, bacteria, animals, and plants. We review many versatile RNA structural elements in the context of different physiological and pathological processes(e.g., cell differentiation, stress response, and viral replication). Finally, we discuss future prospects for RNA structural studies to map the RNA structurome at higher resolution and at the single-molecule and single-cell level, and to decipher novel modes of RNA structures and functions for innovative applications.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.61851405)。
文摘Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devices that can simultaneously obtain low off-state current(IOFF), high on-state current(ION) and steep subthreshold swing(SS). As a key element for the 2D/3D TFET, the intensive exploration of the tunnel diode based on the 2D/3D heterostructure is in urgent need.The transfer technique composed of the exfoliation and the release process is currently the most common approach to fabricating the 2D/3D heterostructures. However, the well-established transfer technique of the 2D materials is still unavailable.Only a small part of the irregular films can usually be obtained by mechanical exfoliation, while the choice of the chemical exfoliation may lead to the contamination of the 2D material films by the ions in the chemical etchants. Moreover, the deformation of the 2D material in the transfer process due to its soft nature also leads to the nonuniformity of the transferred film,which is one of the main reasons for the presence of the wrinkles and the stacks in the transferred film. Thus, the large-scale fabrication of the high-quality 2D/3D tunnel diodes is limited. In this article, a comprehensive transfer technique that can mend up the shortages mentioned above with the aid of the water and the thermal release tape(TRT) is proposed. Based on the method we proposed, the MoS_(2)/Si tunnel diode is experimentally demonstrated and the transferred monolayer MoS_(2) film with the relatively high crystal quality is confirmed by atomic force microscopy(AFM), scanning electron microscopy(SEM), and Raman characterizations. Besides, the prominent negative differential resistance(NDR) effect is observed at room temperature, which verifies the relatively high quality of the MoS_(2)/Si heterojunction. The bilayer MoS_(2)/Si tunnel diode is also experimentally fabricated by repeating the transfer process we proposed, followed by the specific analysis of the electrical characteristics. This study shows the advantages of the transfer technique we proposed and indicates the great application foreground of the fabricated 2D/3D heterostructure for ultralow-power tunneling devices.
文摘This paper analyzes some specific features of the numerical interpretation of high-frequency electromagnetic logging data in vertical, deviated and horizontal boreholes entering oil- and water-saturated formations. The interpretation is based on numerical modeling for signals.
基金This study was performed at the Center for Rock Instability&Seismicity Research(CRISR),Shenyang,ChinaThe work presented in this paper was financially supported by the General Project of the National Natural Science Foundation of China(Grant Nos.51174045,50904013,51034001,and 50934006)+1 种基金the National Basic Research Program of China(No.2013CB227900)basic scientific research funds of Ministry of Education of China(Nos.N090101001,N110601003 and N100401003).
文摘Geometrical parameters of discontinuities,such as spacing,length,dip and fault throw between joints have a great influence on the mechanical behavior of jointed rock masses.Accurate characterization for discontinuities is important for investigate the stability of rock masses.In this paper,the PFC2D is combined with joint network generation method to examine the mechanical behaviors of jointed mass.Taking Miaogou Open-pit Mine as an example,the information and statistical distributions of discontinuities of the slope rock masses are measured by ShapeMetriX3D measuring tool.Then,the automatic generation algorithm of random joints network based on the Monte-Carlo method is proposed using the programming language(FISH)embedded within PFC2D.This algorithm could represent the discontinuities compared with the geological surveys.In simulating the compression test of a jointed rock sample,the mechanical behavior and crack propagation were investigated.The results reveal that the failure mode and crack propagation of the jointed rock are dominated by the distribution of joints in addition to the intact rock properties.The simulation result shows the feasibility of the joints generating method in application to jointed rock mass.
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.61622107 and 61871146)the Fundamental Research Funds for the Central Universities
文摘There are great challenges for traditional three-dimensional( 3-D) interferometric inverse synthetic aperture radar( In ISAR) imaging algorithms of ship targets w ith 2-D sparsity in actual radar imaging system. To deal w ith this problem,a novel 3-D In ISAR imaging method is proposed in this paper.First,the high-precision gradient adaptive algorithm w as adopted to reconstruct the echoes in range dimension. Then the method of minimizing the entropy of the average range profile w as applied to estimate the parameters w hich are used to compensate translation components of the received echoes. Besides,the phase adjustment and image coregistration of the sparse echoes w ere achieved at the same time through the approach of the joint phase autofocus. Finally,the 3-D geometry coordinates of the ship target w ith 2-D sparsity w ere reconstructed by combining the range measurement and interferometric processing of the ISAR images. Simulation experiments w ere carried out to verify the practicability and effectiveness of the algorithm in the case that the received echoes are in 2-D sparsity.
基金supported by the National Key Research and Development Program of China(2021YFE0114900)the National Natural Science Foundation of China(91940303,91940306,32025008,32170262,31922039,U1832215,32170229)+6 种基金the Natural Science Foundation of Zhejiang Province(LD21C050002)the Starry Night Science Fund at Shanghai Institute for Advanced Study of Zhejiang University(SN-ZJU-SIAS-009)the Beijing Advanced Innovation Center for Structural Biology,Shenzhen Basic Research Project(JCYJ20180507181642811)Research Grants Council of the Hong Kong SAR,China Projects(City U 11100421,City U 11101519,City U 11100218,N_City U110/17)Croucher Foundation Project(9509003)State Key Laboratory of Marine Pollution Director Discretionary Fund,City University of Hong Kong Projects(7005503,9667222,9680261)the United Kingdom Biotechnology and Biological Sciences Research Council(BBSRC:BBS/E/J/000PR9788)。
文摘RNA structures are essential to support RNA functions and regulation in various biological processes. Recently, a range of novel technologies have been developed to decode genome-wide RNA structures and novel modes of functionality across a wide range of species. In this review, we summarize key strategies for probing the RNA structurome and discuss the pros and cons of representative technologies. In particular, these new technologies have been applied to dissect the structural landscape of the SARS-CoV-2 RNA genome. We also summarize the functionalities of RNA structures discovered in different regulatory layers-including RNA processing, transport, localization, and mRNA translation-across viruses, bacteria, animals, and plants. We review many versatile RNA structural elements in the context of different physiological and pathological processes(e.g., cell differentiation, stress response, and viral replication). Finally, we discuss future prospects for RNA structural studies to map the RNA structurome at higher resolution and at the single-molecule and single-cell level, and to decipher novel modes of RNA structures and functions for innovative applications.
