Gerotor pump is a special kind of internal rotary pump, which contains a trochoid profile (commonly called as cycloid). Generation of trochoid is normally realized by external rolling method, namely a circle rotating ...Gerotor pump is a special kind of internal rotary pump, which contains a trochoid profile (commonly called as cycloid). Generation of trochoid is normally realized by external rolling method, namely a circle rotating on a fixed circle without slipping. This paper proposes derivative process of the trochoid profile by means of internal rolling method, which is that internal surface of a circle contacts with a fixed circle and rotates around it without slipping. Moreover the instantaneous flow rate can be obtained by numerically calculating the change ratio of area between the inner and outer rotors in the outlet region of the gerotor pump, which avoids to complicatedly derivative process.展开更多
Optical properties of graded InGaN/GaN quantum well(QW)lasers are analyzed as improved gain media for laser diodes emitting near 500 nm.These results are compared with those of conventional InGaN/GaN QW structures.The...Optical properties of graded InGaN/GaN quantum well(QW)lasers are analyzed as improved gain media for laser diodes emitting near 500 nm.These results are compared with those of conventional InGaN/GaN QW structures.The heavy-hole effective mass around the topmost valence band is found to nearly not be affected by the inclusion of the graded layer.The graded InGaN/GaN QW structure shows a much larger matrix element than the conventional InGaN/GaN QW structure.The radiative current density dependences of the optical gain are similar to each other.However,the graded QW structure is expected to have lower threshold current density than the conventional QW structure because the former has a lower threshold carrier density than the latter.展开更多
Optical properties of single emitters can be significantly improved through the interaction with plasmonic structures,leading to enhanced sensing and imaging capabilities.In turn,single emitters can act as sensitive p...Optical properties of single emitters can be significantly improved through the interaction with plasmonic structures,leading to enhanced sensing and imaging capabilities.In turn,single emitters can act as sensitive probes of the local electromagnetic field surrounding plasmonic structures,furnishing fundamental insights into their physics and guiding the design of novel plasmonic devices.However,the interaction of emitters in the proximity to a plasmonic nanostructure causes distortion,which hinders precise estimation of position and polarization state and is one of the reasons why detection and quantification of molecular processes yet remain fundamentally challenging in this era of super-resolution.Here,we investigate axially defocused images of a single fluorescent emitter near metallic nanostructure,which encode emitter positions and can be acquired in the far-field with high sensitivity,while analyzing the images with pattern matching algorithm to explore emitter-localized surface plasmon interaction and retrieve information regarding emitter positions.Significant distortion in defocused images of fluorescent beads and quantum dots near nanostructure was observed and analyzed by pattern matching and finite-difference time-domain methods,which revealed that the distortion arises from the emitter interaction with nanostructure.Pattern matching algorithm was also adopted to estimate the lateral positions of a dipole that models an emitter utilizing the distorted defocused images and achieved improvement by more than 3 times over conventional diffraction-limited localization methods.The improvement by defocused imaging is expected to provide a way of enhancing reliability when using plasmonic nanostructure and diversifying strategies for various imaging and sensing modalities.展开更多
文摘Gerotor pump is a special kind of internal rotary pump, which contains a trochoid profile (commonly called as cycloid). Generation of trochoid is normally realized by external rolling method, namely a circle rotating on a fixed circle without slipping. This paper proposes derivative process of the trochoid profile by means of internal rolling method, which is that internal surface of a circle contacts with a fixed circle and rotates around it without slipping. Moreover the instantaneous flow rate can be obtained by numerically calculating the change ratio of area between the inner and outer rotors in the outlet region of the gerotor pump, which avoids to complicatedly derivative process.
基金by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(2009-0071446).
文摘Optical properties of graded InGaN/GaN quantum well(QW)lasers are analyzed as improved gain media for laser diodes emitting near 500 nm.These results are compared with those of conventional InGaN/GaN QW structures.The heavy-hole effective mass around the topmost valence band is found to nearly not be affected by the inclusion of the graded layer.The graded InGaN/GaN QW structure shows a much larger matrix element than the conventional InGaN/GaN QW structure.The radiative current density dependences of the optical gain are similar to each other.However,the graded QW structure is expected to have lower threshold current density than the conventional QW structure because the former has a lower threshold carrier density than the latter.
基金supported by the National Research Foundation of Korea under Grant NRF-2022R1A4A2000748 and Y-BASE R&E Institute,a Brain Korea 21 four program,Yonsei University.
文摘Optical properties of single emitters can be significantly improved through the interaction with plasmonic structures,leading to enhanced sensing and imaging capabilities.In turn,single emitters can act as sensitive probes of the local electromagnetic field surrounding plasmonic structures,furnishing fundamental insights into their physics and guiding the design of novel plasmonic devices.However,the interaction of emitters in the proximity to a plasmonic nanostructure causes distortion,which hinders precise estimation of position and polarization state and is one of the reasons why detection and quantification of molecular processes yet remain fundamentally challenging in this era of super-resolution.Here,we investigate axially defocused images of a single fluorescent emitter near metallic nanostructure,which encode emitter positions and can be acquired in the far-field with high sensitivity,while analyzing the images with pattern matching algorithm to explore emitter-localized surface plasmon interaction and retrieve information regarding emitter positions.Significant distortion in defocused images of fluorescent beads and quantum dots near nanostructure was observed and analyzed by pattern matching and finite-difference time-domain methods,which revealed that the distortion arises from the emitter interaction with nanostructure.Pattern matching algorithm was also adopted to estimate the lateral positions of a dipole that models an emitter utilizing the distorted defocused images and achieved improvement by more than 3 times over conventional diffraction-limited localization methods.The improvement by defocused imaging is expected to provide a way of enhancing reliability when using plasmonic nanostructure and diversifying strategies for various imaging and sensing modalities.
