A novel stitching machining method for ion beam figuring of optical mirrors is presented in this paper. Problems that should be dealt with in the stitching process such as shaping principle,algorithm for dwell time ca...A novel stitching machining method for ion beam figuring of optical mirrors is presented in this paper. Problems that should be dealt with in the stitching process such as shaping principle,algorithm for dwell time calculation,parameter identification and compensation for positioning errors are discussed. Based on Computer Controlled Optical Surfacing(CCOS)principle,the finite field nonlinear model is deduced from the stitching shaping mechanism;with the superposition property in the model,a modified Richardson-Lucy iterative algorithm is presented to deconvolute the dwell time for the stitching process;the effect of the positioning errors and the removal rate on the machining accuracy and shape is modeled and then the identification and compensation algorithm for these parameters is proposed based on this model.With these studies,shaping theory and algorithm are constructed,and then the stitching process for ion beam figuring comes into being.Figuring experiments are made on planar samples;the process convergence ratio is 10,which is similar to that in full aperture figuring.Theo- retical and experimental studies indicate that the stitching theory and algorithm in the ion beam figuring process presented in this paper are a novel method for fabrication of precision mirrors with lower cost.展开更多
Optics with high-precision height and slope are increasingly desired in numerous industrial fields.For instance,Kirkpatrick-Baez(KB)mirrors play an important role in synchrotron X-ray applications.A KB system is compo...Optics with high-precision height and slope are increasingly desired in numerous industrial fields.For instance,Kirkpatrick-Baez(KB)mirrors play an important role in synchrotron X-ray applications.A KB system is composed of two aspherical,grazing-incidence mirrors used to focus an X-ray beam.The fabrication of KB mirrors is challenging due to the aspherical departure of the mirror surfaces from base geometries and the high-quality requirements for slope and height residuals.In this paper,we present the process of manufacturing an elliptical cylinder KB mirror using our in-house-developed ion beam figuring(IBF)and metrology technologies.First,the key aspects of figuring and finishing processes with IBF are illustrated in detail.The effect of positioning error on the convergence of the residual slope error is highlighted and compensated.Finally,inspection and cross-validation using different metrology instruments are performed and used as the final validation of the mirror.Results confirm that relative to the requested off-axis ellipse,the mirror has achieved 0.15-μrad root mean square(RMS)and 0.36-nm RMS residual slope and height errors,respectively,while maintaining the initial 0.3-nm RMS microroughness.展开更多
Ion beam figuring （IBF） technology is an effective technique for fabricating continuous phase plates （CPPs） with small feature structures. This study proposes a multi-pass IBF approach with different beam diameter...Ion beam figuring （IBF） technology is an effective technique for fabricating continuous phase plates （CPPs） with small feature structures. This study proposes a multi-pass IBF approach with different beam diameters based on the frequency filtering method to improve the machining accuracy and efficiency of CPPs during IBF. We present the selection principle of the frequency filtering method, which incorporates different removal functions that maximize material removal over the topographical frequencies being imprinted. Large removal functions are used early in the fabrication to figure the surface profile with low frequency. Small removal functions are used to perform final topographical correction with higher fre- quency and larger surface gradient. A high-precision surface can be obtained as long as the filtering frequency is suitably selected. This method maximizes the high removal efficiency of the large removal function and the high corrective capability of the small removal function. Consequently, the fast convergence of the machining accuracy and efficiency can be achieved.展开更多
Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented...Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented a biased life assessment.Lauded as a founding suffragette,the first female school principal,and the first white female practicing physician in Canada,Dr.Emily Stowe did not help historians.She destroyed her records,leaving her life story to be told by her daughter,who portrayed her as a heroine–a view that has persisted since the start of the 20th century.To improve the accuracy of assessing the life of Emily Stowe,as much information as possible about Stowe must be collected and interpreted.Methods:Presented is a narrative research method for analyzing historical figures that examines 22 life-changing events in the life of Stowe by answering six types of questions about each event:when,where,who,what,how,and why.Results:This narrative research,representing a psychoanalytic research process,finds that much of the repeated story of Stowe is either exaggerated or likely false.Conclusion:Following the example of Emily Stowe,this unique method is applicable for improving the historical accuracy in assessing the lives of other notable figures.It represents a method extendable to those currently alive,outside the public eye,searching to develop their own narrative.展开更多
Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,...Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in mice.The cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)proteins.The cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).展开更多
The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ ...The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ structure is classically described as having a“pretzel-like”shape in mice(Figure 1),whereas human NMJs have a smaller,fragmented structure throughout adulthood.Degenerated NMJs exhibit smaller or fragmented endplates,partial denervation,reduced numbers of synaptic vesicles,abnormal presynaptic mitochondria,and dysfunctional perisynaptic Schwann cells(Alhindi et al.,2022).展开更多
Adult microglia,by continuously sensing changes in their environment and communicating with nearly all brain cell types,are considered to be the immune sentinels of the brain.In the healthy central nervous system(CNS)...Adult microglia,by continuously sensing changes in their environment and communicating with nearly all brain cell types,are considered to be the immune sentinels of the brain.In the healthy central nervous system(CNS),microglia display a unique molecular homeostatic signature(i.e.,Tmem119,P2ry12,Sall1,Siglech,Gpr34,and Hexb)(Figure 1A).展开更多
At the request of the authors,Neural Regeneration Research is retracting the research article titled"The effects of exercise interventions on brain-derived neurotrophic factor levels in children and adolescents:a...At the request of the authors,Neural Regeneration Research is retracting the research article titled"The effects of exercise interventions on brain-derived neurotrophic factor levels in children and adolescents:a meta-analysis"(Shao et al.,2025;doi:10.4103/NRR.NRR-D-23-01296)due to erroneous data in Figure 4,which were produced during data extraction and synthesis.These erroneous analysis results lead to unreliable findings and misleading conclusions.展开更多
The metabolite lactate (L-lactate) can be generated and released by diverse brain cells,including neurons,astrocytes,and oligodendrocytes (Kann,2023;Rae et al.,2024).Lactate production usually requires the degradation...The metabolite lactate (L-lactate) can be generated and released by diverse brain cells,including neurons,astrocytes,and oligodendrocytes (Kann,2023;Rae et al.,2024).Lactate production usually requires the degradation of glucose (D-glucose)-and glycogen in astrocytes-to pyruvate by glycolysis and subsequent conversion of pyruvate to lactate by the enzyme lactate dehydrogenase(Figure 1A;Dienel,2019;Rae et al.,2024).展开更多
Following the publication of Xu et al.(2022),an error was identified in Figure 1D.Specifically,the top left panel was inadvertently duplicated during figure preparation.To ensure the accuracy and integrity of our publ...Following the publication of Xu et al.(2022),an error was identified in Figure 1D.Specifically,the top left panel was inadvertently duplicated during figure preparation.To ensure the accuracy and integrity of our published work,we request the publication of a corrigendum with the corrected image.We apologize for this oversight and any confusion it may have caused.The amended figure is provided in the updated Supplementary Materials.展开更多
Following the publication of Liu et al.(2024),an error was identified in Figure 4B,in which the image representing the lung from the E529G group was inadvertently duplicated with the image of the lung from the WT grou...Following the publication of Liu et al.(2024),an error was identified in Figure 4B,in which the image representing the lung from the E529G group was inadvertently duplicated with the image of the lung from the WT group during figure preparation.展开更多
The authors(Cai et al.,2022)claim that their proposed machine learning(ML)models,which are based on three typical ML algorithms and are trained to predict the burst capacity of pitting corroded pipelines,perform bette...The authors(Cai et al.,2022)claim that their proposed machine learning(ML)models,which are based on three typical ML algorithms and are trained to predict the burst capacity of pitting corroded pipelines,perform better than the existing semi-empirical formulas recommended by the international engineering code developers,DNV and ASME.The authors’assessments of the semi-empiri‐cal burst capacity formulas in Figure 10(a)and Table 8(Cai et al.,2022)incorrectly indicate that DNVGL-RP F101,ASME B31G,and modified ASME B31G are dan‐gerously unsafe due to significantly overestimating burst pressures in several cases.In contrast to the results and conclusions in Cai et al.展开更多
1Legal requirements The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and t...1Legal requirements The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.展开更多
1Legal requirements.The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and t...1Legal requirements.The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.展开更多
During the final proofing stage of the paper,the wrong version of Fig.2 was accidently used when replacing it with a high-resolution version.The star and circle marks were missing in the published version.
During the process of organizing our original data,we unfortunately identified two error in the figures within our published article.In Fig.1,the online version incorrectly labels the SNI+NAC group as the sham+NAC gro...During the process of organizing our original data,we unfortunately identified two error in the figures within our published article.In Fig.1,the online version incorrectly labels the SNI+NAC group as the sham+NAC group.We have revised the grouping annotations in Fig.1 and have labeled the DHE staining in the figure to present the experimental design more clearly.展开更多
In the era of rapidly expanding wireless technologies,the push for larger spectrum efficiency and better signal integrity has intensified the need for high-efficient and low noise amplifiers(LNAs).A two-stage LNA base...In the era of rapidly expanding wireless technologies,the push for larger spectrum efficiency and better signal integrity has intensified the need for high-efficient and low noise amplifiers(LNAs).A two-stage LNA based on the GaAs/InGaAs pseudomorphic high electron mobility transistor(pHEMT)with a relatively large gate length of 2μm is designed for high-performance 2.4-GHz wireless communication.The I-V characteristic and two-port high-frequency S-parameter of the transistor are measured by on-wafer probing techniques.The results indicate that a discrete transistor with a gate size of 2μm×50μm can provide a maximum transconductance of 16 mS,corresponding to a maximum current-gain cut-off frequency of 7 GHz and maximum oscillation frequency of 8 GHz at the 1-V drain-source voltage.With the impedance matching networks based transmission line technique,an extended integrated layout structure is designed and simulated by using the momentum simulation tool embedded in Advanced Design System,to alleviate the trade-off between noise figure(NF)and gain of the circuit.The findings show that the transistor based on the GaAs/InGaAs technology is capable of delivering high performance with power consumption low to 16 mW,where the maximum simulated gain of 21.5 dB and minimum NF of 2.4 dB are achieved.In terms of linearity,the proposed LNA provides terrific output 1-dB compression of-3 dBm and output third-order intercept point values of 10 dBm.The bandwidth of 0.12 GHz and figure-of-merit of 12 are obtained,which are comparable to that of existing LNAs based on pHEMT.Such a device may benefit to accelerate the development of more robust and power-efficient front-end modules in modern wireless systems,especially for advancing performance-driven applications.展开更多
Spintronic technology and energy applications benefit greatly from the exceptional characteristics of rare-earth-based spinel chalcogenides.Examining the electrical,magnetic and thermoelectric properties of HgNd_(2)Z_...Spintronic technology and energy applications benefit greatly from the exceptional characteristics of rare-earth-based spinel chalcogenides.Examining the electrical,magnetic and thermoelectric properties of HgNd_(2)Z_(4)(Z=S,Se)in a systematic manner is essential for the strategic advancement of spin polarized current in a spintronic device.In this recent study,the WIEN2K code was employed to comprehensively analyze these properties.The calculated lattice constants,obtained using the generalized gradient approximation(GGAsol-PBE),closely match experimental findings of the similar family compounds.The examination of the stability of ferromagnetic states in the ground state involves comparing energies between anti-ferromagnetic and ferromagnetic states.Moreover,an assessment of the stability of the cubic phase in both spinels was conducted using analyses of the phonon dispersion curve,formation energy and Born stability criteria.The ductility characteristics were examined through the calculation of Poisson's and Pugh's ratios.Furthermore,details regarding the density of states,spin polarization,ex-change coupling and Curie temperature were provided to explore the characteristics associated with ferromagnetism.Potential optoelectronic applications were proposed,leveraging the direct band gaps of 1.4 and 1.0 eV for HgNd_(2)Z_(4)(Z=S,Se)respectively,within the visible spectrum.Particularly noteworthy is the effective light absorption of HgNd2Se4 in the visible range,characterized by prominent peaks that facilitate the transition of electrons from the valence band(VB)to the conduction band(CB).Additionally,the study extends to thermoelectric characteristics,determining various factors such as Seebeck coef-ficient(S),figure of merit(ZT),electrical and thermal conductivities of the evaluated spinels.展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.50775216)
文摘A novel stitching machining method for ion beam figuring of optical mirrors is presented in this paper. Problems that should be dealt with in the stitching process such as shaping principle,algorithm for dwell time calculation,parameter identification and compensation for positioning errors are discussed. Based on Computer Controlled Optical Surfacing(CCOS)principle,the finite field nonlinear model is deduced from the stitching shaping mechanism;with the superposition property in the model,a modified Richardson-Lucy iterative algorithm is presented to deconvolute the dwell time for the stitching process;the effect of the positioning errors and the removal rate on the machining accuracy and shape is modeled and then the identification and compensation algorithm for these parameters is proposed based on this model.With these studies,shaping theory and algorithm are constructed,and then the stitching process for ion beam figuring comes into being.Figuring experiments are made on planar samples;the process convergence ratio is 10,which is similar to that in full aperture figuring.Theo- retical and experimental studies indicate that the stitching theory and algorithm in the ion beam figuring process presented in this paper are a novel method for fabrication of precision mirrors with lower cost.
基金This work was supported by the Accelerator and Detector Research Program,part of the Scientific User Facility Division of the Basic Energy Science Office of the US Department of Energy(DOE),under the Field Work Proposal No.PS032This research was performed at the Optical Metrology Laboratory at the National Synchrotron Light Source II,a US DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory(BNL)under Contract No.DE-SC0012704This work was performed under the BNL LDRD 17-016‘Diffraction limited and wavefront preserving reflective optics development’.
文摘Optics with high-precision height and slope are increasingly desired in numerous industrial fields.For instance,Kirkpatrick-Baez(KB)mirrors play an important role in synchrotron X-ray applications.A KB system is composed of two aspherical,grazing-incidence mirrors used to focus an X-ray beam.The fabrication of KB mirrors is challenging due to the aspherical departure of the mirror surfaces from base geometries and the high-quality requirements for slope and height residuals.In this paper,we present the process of manufacturing an elliptical cylinder KB mirror using our in-house-developed ion beam figuring(IBF)and metrology technologies.First,the key aspects of figuring and finishing processes with IBF are illustrated in detail.The effect of positioning error on the convergence of the residual slope error is highlighted and compensated.Finally,inspection and cross-validation using different metrology instruments are performed and used as the final validation of the mirror.Results confirm that relative to the requested off-axis ellipse,the mirror has achieved 0.15-μrad root mean square(RMS)and 0.36-nm RMS residual slope and height errors,respectively,while maintaining the initial 0.3-nm RMS microroughness.
基金Acknowledgements We gratefully acknowledge the support of the National Natural Science Foundation of China （Grant Nos. 91323302 and 61505259） and the Program for New Century Excellent Talents in University （NCET- 13 -0165）.
文摘Ion beam figuring （IBF） technology is an effective technique for fabricating continuous phase plates （CPPs） with small feature structures. This study proposes a multi-pass IBF approach with different beam diameters based on the frequency filtering method to improve the machining accuracy and efficiency of CPPs during IBF. We present the selection principle of the frequency filtering method, which incorporates different removal functions that maximize material removal over the topographical frequencies being imprinted. Large removal functions are used early in the fabrication to figure the surface profile with low frequency. Small removal functions are used to perform final topographical correction with higher fre- quency and larger surface gradient. A high-precision surface can be obtained as long as the filtering frequency is suitably selected. This method maximizes the high removal efficiency of the large removal function and the high corrective capability of the small removal function. Consequently, the fast convergence of the machining accuracy and efficiency can be achieved.
文摘Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented a biased life assessment.Lauded as a founding suffragette,the first female school principal,and the first white female practicing physician in Canada,Dr.Emily Stowe did not help historians.She destroyed her records,leaving her life story to be told by her daughter,who portrayed her as a heroine–a view that has persisted since the start of the 20th century.To improve the accuracy of assessing the life of Emily Stowe,as much information as possible about Stowe must be collected and interpreted.Methods:Presented is a narrative research method for analyzing historical figures that examines 22 life-changing events in the life of Stowe by answering six types of questions about each event:when,where,who,what,how,and why.Results:This narrative research,representing a psychoanalytic research process,finds that much of the repeated story of Stowe is either exaggerated or likely false.Conclusion:Following the example of Emily Stowe,this unique method is applicable for improving the historical accuracy in assessing the lives of other notable figures.It represents a method extendable to those currently alive,outside the public eye,searching to develop their own narrative.
基金supported by R01 NS093009 grant from NIH(to VVC).
文摘Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in mice.The cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)proteins.The cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).
基金funded by the Japan Society for the Promotion of Science,JSPS,23K07290(to MF).
文摘The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ structure is classically described as having a“pretzel-like”shape in mice(Figure 1),whereas human NMJs have a smaller,fragmented structure throughout adulthood.Degenerated NMJs exhibit smaller or fragmented endplates,partial denervation,reduced numbers of synaptic vesicles,abnormal presynaptic mitochondria,and dysfunctional perisynaptic Schwann cells(Alhindi et al.,2022).
基金supported by NIH grants(R01NS125074,R01AG083164,and R21NS127177)(to YL).
文摘Adult microglia,by continuously sensing changes in their environment and communicating with nearly all brain cell types,are considered to be the immune sentinels of the brain.In the healthy central nervous system(CNS),microglia display a unique molecular homeostatic signature(i.e.,Tmem119,P2ry12,Sall1,Siglech,Gpr34,and Hexb)(Figure 1A).
文摘At the request of the authors,Neural Regeneration Research is retracting the research article titled"The effects of exercise interventions on brain-derived neurotrophic factor levels in children and adolescents:a meta-analysis"(Shao et al.,2025;doi:10.4103/NRR.NRR-D-23-01296)due to erroneous data in Figure 4,which were produced during data extraction and synthesis.These erroneous analysis results lead to unreliable findings and misleading conclusions.
文摘The metabolite lactate (L-lactate) can be generated and released by diverse brain cells,including neurons,astrocytes,and oligodendrocytes (Kann,2023;Rae et al.,2024).Lactate production usually requires the degradation of glucose (D-glucose)-and glycogen in astrocytes-to pyruvate by glycolysis and subsequent conversion of pyruvate to lactate by the enzyme lactate dehydrogenase(Figure 1A;Dienel,2019;Rae et al.,2024).
文摘Following the publication of Xu et al.(2022),an error was identified in Figure 1D.Specifically,the top left panel was inadvertently duplicated during figure preparation.To ensure the accuracy and integrity of our published work,we request the publication of a corrigendum with the corrected image.We apologize for this oversight and any confusion it may have caused.The amended figure is provided in the updated Supplementary Materials.
文摘Following the publication of Liu et al.(2024),an error was identified in Figure 4B,in which the image representing the lung from the E529G group was inadvertently duplicated with the image of the lung from the WT group during figure preparation.
文摘The authors(Cai et al.,2022)claim that their proposed machine learning(ML)models,which are based on three typical ML algorithms and are trained to predict the burst capacity of pitting corroded pipelines,perform better than the existing semi-empirical formulas recommended by the international engineering code developers,DNV and ASME.The authors’assessments of the semi-empiri‐cal burst capacity formulas in Figure 10(a)and Table 8(Cai et al.,2022)incorrectly indicate that DNVGL-RP F101,ASME B31G,and modified ASME B31G are dan‐gerously unsafe due to significantly overestimating burst pressures in several cases.In contrast to the results and conclusions in Cai et al.
文摘1Legal requirements The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.
文摘1Legal requirements.The author(s)guarantee(s)that the manuscript will not be published elsewhere in any language without the consent of the copyright holders,that the rights of third parties will not be violated,and that the publisher will not be held legally responsible should there be any claims for compensation.Authors wishing to include figures or text passages that have already been published elsewhere are required to obtain permission from the copyright holder(s)and to include evidence that such permission has been granted when submitting their papers.Any material received without such evidence will be assumed to originate from the authors.
文摘During the final proofing stage of the paper,the wrong version of Fig.2 was accidently used when replacing it with a high-resolution version.The star and circle marks were missing in the published version.
文摘During the process of organizing our original data,we unfortunately identified two error in the figures within our published article.In Fig.1,the online version incorrectly labels the SNI+NAC group as the sham+NAC group.We have revised the grouping annotations in Fig.1 and have labeled the DHE staining in the figure to present the experimental design more clearly.
基金supported by Engineering and Physical Sciences Research Council(EPSRC)under Grant No.EP/P006973/1.
文摘In the era of rapidly expanding wireless technologies,the push for larger spectrum efficiency and better signal integrity has intensified the need for high-efficient and low noise amplifiers(LNAs).A two-stage LNA based on the GaAs/InGaAs pseudomorphic high electron mobility transistor(pHEMT)with a relatively large gate length of 2μm is designed for high-performance 2.4-GHz wireless communication.The I-V characteristic and two-port high-frequency S-parameter of the transistor are measured by on-wafer probing techniques.The results indicate that a discrete transistor with a gate size of 2μm×50μm can provide a maximum transconductance of 16 mS,corresponding to a maximum current-gain cut-off frequency of 7 GHz and maximum oscillation frequency of 8 GHz at the 1-V drain-source voltage.With the impedance matching networks based transmission line technique,an extended integrated layout structure is designed and simulated by using the momentum simulation tool embedded in Advanced Design System,to alleviate the trade-off between noise figure(NF)and gain of the circuit.The findings show that the transistor based on the GaAs/InGaAs technology is capable of delivering high performance with power consumption low to 16 mW,where the maximum simulated gain of 21.5 dB and minimum NF of 2.4 dB are achieved.In terms of linearity,the proposed LNA provides terrific output 1-dB compression of-3 dBm and output third-order intercept point values of 10 dBm.The bandwidth of 0.12 GHz and figure-of-merit of 12 are obtained,which are comparable to that of existing LNAs based on pHEMT.Such a device may benefit to accelerate the development of more robust and power-efficient front-end modules in modern wireless systems,especially for advancing performance-driven applications.
基金the Deanship of Scientific Research at King Khalid University for funding this work through large group Research Project under grant number RGP2/450/44。
文摘Spintronic technology and energy applications benefit greatly from the exceptional characteristics of rare-earth-based spinel chalcogenides.Examining the electrical,magnetic and thermoelectric properties of HgNd_(2)Z_(4)(Z=S,Se)in a systematic manner is essential for the strategic advancement of spin polarized current in a spintronic device.In this recent study,the WIEN2K code was employed to comprehensively analyze these properties.The calculated lattice constants,obtained using the generalized gradient approximation(GGAsol-PBE),closely match experimental findings of the similar family compounds.The examination of the stability of ferromagnetic states in the ground state involves comparing energies between anti-ferromagnetic and ferromagnetic states.Moreover,an assessment of the stability of the cubic phase in both spinels was conducted using analyses of the phonon dispersion curve,formation energy and Born stability criteria.The ductility characteristics were examined through the calculation of Poisson's and Pugh's ratios.Furthermore,details regarding the density of states,spin polarization,ex-change coupling and Curie temperature were provided to explore the characteristics associated with ferromagnetism.Potential optoelectronic applications were proposed,leveraging the direct band gaps of 1.4 and 1.0 eV for HgNd_(2)Z_(4)(Z=S,Se)respectively,within the visible spectrum.Particularly noteworthy is the effective light absorption of HgNd2Se4 in the visible range,characterized by prominent peaks that facilitate the transition of electrons from the valence band(VB)to the conduction band(CB).Additionally,the study extends to thermoelectric characteristics,determining various factors such as Seebeck coef-ficient(S),figure of merit(ZT),electrical and thermal conductivities of the evaluated spinels.
