Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater o...Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.展开更多
Objective: To report complications related to flap around implants after cochlear implantation, possible causes of such complications and treatments. Methods and material:We performed a retrospective analysis of child...Objective: To report complications related to flap around implants after cochlear implantation, possible causes of such complications and treatments. Methods and material:We performed a retrospective analysis of children in whom complications related to flap around implants occurred after undergoing cochlear implantation in our department from 2005 to 2016. Results:Complications among 1500 cochlear implantation (CI) recipients by the same surgeon included hematoma (n ? 20) and seroma around implants (n ? 15), of which most (n ? 10) recovered in 2 weeks after effective drainage, utility of antibiotics and pressure dressing, but 5 developed flap necrosis and had to undergo contralateral re-implantation. Four patients developed abscess around implants, of whom 2 recovered after 2 weeks of drainage, gentamicin irrigation and use of antibiotics, but 2 patients ended up with flap necrosis and had to receive contralateral reimplantation. Conclusions: Immediate drainage, pressure dressing and antibiotics can be used to effectively control seroma around implants. For seroma lasting for more than two weeks without improvement, surgical drainage may be need.展开更多
Objective: A common cavity deformity(CCD) is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity that results in profound hearing loss. There are few studie...Objective: A common cavity deformity(CCD) is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity that results in profound hearing loss. There are few studies paying attention to common cavity. Our group is engrossed in observing the improvement of auditory and verbal abilities in children who have received cochlear implantation(CI), and comparing these targets between children with common cavity and normal inner ear structure.Material and methods: A retrospective study was conducted in 12 patients with profound hearing loss that were divided into a common cavity group and a control group, six in each group matched in sex, age and time of implantation, based on inner ear structure. Categories of Auditory Performance(CAP) and speech intelligibility rating(SIR) scores and aided hearing thresholds were collected and compared between the two groups. All patients wore CI for more than 1 year at the Cochlear Center of Anhui Medical University from 2011 to 2015.Results: Postoperative CAP and SIR scores were higher than before operation in both groups(p < 0.05), although the scores were lower in the CCD group than in the control group(p < 0.05). The aided threshold was also lower in the control group than in the CCD group(p < 0.05).Conclusion: Even though audiological improvement in children with CCD was not as good as in those without CCD, CI provides benefits in auditory perception and communication skills in these children.展开更多
All-inorganic,hole-transporting-layer-free CsPbIBr_(2)perovskite solar cells have great potential for development,but their device performance needs to be further improved.Recently,metal nanostructures have been succe...All-inorganic,hole-transporting-layer-free CsPbIBr_(2)perovskite solar cells have great potential for development,but their device performance needs to be further improved.Recently,metal nanostructures have been successfully applied in the field of solar cells to improve their performance.Nano Ag-enhanced power conversion efficiency(PCE)in one CsPbIBr_(2)perovskite solar cell utilizing localized surface plasmons of Ag nanoparticles(NPs)on the surface has been researched experimentally and by simulation in this paper.The localized surface plasmon resonance of Ag NPs has a near-field enhancement effect,which is expected to improve the light absorption of CsPbIBr_(2)perovskite photovoltaic devices.In addition,Ag NPs have a forward-scattering effect on the incident light,which can also improve the performance of CsPbIBr_(2)-based perovskite photovoltaic devices.By directly assembling Ag NPs(with a size of about 150 nm)on the surface of fluorine-doped tin oxide it is found when the particle surface coverage is 10%,the CsPbIBr_(2)perovskite photovoltaic device achieves a best PCE of 2.7%,which is 9.76%higher than that of the control group.Without changing any existing structure in the ready-made solar cell,this facile and efficient method has huge applications.To the best of our knowledge,this paper is the first report on nano Ag-enhanced photoelectric conversion efficiency in this kind of CsPbIBr_(2)perovskite solar cell.展开更多
Optical gain and loss of microcavity greatly affect the quality of lasing,how to improve optical gain and decrease optical loss is of great significance for the preparation of laser.In this study,four types standard m...Optical gain and loss of microcavity greatly affect the quality of lasing,how to improve optical gain and decrease optical loss is of great significance for the preparation of laser.In this study,four types standard microdisks with different thicknesses of 2.2μm,1.9μm,1.7μm,and 1.45μm were fabricated by micromachining technology process to modulate optical gain and loss of microdisk lasing.The whispering gallery mode lasing in the ultraviolet range of Ga N microdisk devices was investigated for these devices in order to clarify the effect of microdisk thickness on device characteristics.The quality factor Q and lasing mode number for different thicknesses are calculated from the stimulated spectra.The lifetimes of the exciton combination properties of the devices were observed using time-resolved PL spectroscopy.The lasing modes are modulated,and the lifetime decreases,while the Q factor of the devices first increases and then decreases with decreasing thickness.All these results are induced by optical gain and loss competition.展开更多
Using an identical monolithic InGaN/GaN light emitting diode (LED) array as the sensing module and a well-designed data processing module, we demonstrate a small-size concentration sensing prototype. Overlap between t...Using an identical monolithic InGaN/GaN light emitting diode (LED) array as the sensing module and a well-designed data processing module, we demonstrate a small-size concentration sensing prototype. Overlap between the emission and the response spectra of the InGaN/GaN LED makes each pair of LEDs in the arrayed chip form a sensing channel. The changes in liquid concentration can be transformed into variation of photocurrent. The system's sensing properties are further optimized by varying the position, number of receivers, and packaging reflectors. With methyl orange as a tracer agent, the sensing system's resolution is 0.286 μmol/L with a linear measurement region below 40 μmol/L.展开更多
Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matte...Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matter interactions to laser applications[1].Undergoing decades of development,the improvement of lasing performance is always a significant issue,including low threshold and high quality(Q)factor[2].Increasing optical gain and reducing the losses are the key aspects towards the realization of a high-quality WGM laser.A perfect cavity structure and a smooth surface are the most crucial determinants to reduce optical losses and enhance light field confined abilities.展开更多
Reaction kinetics of nanoparticles can be controlled by tuning the Peclet number(Pe)as it is an essential parameter in synthesis of multi-sized nanoparticles.Herein,we propose to implement a self-driven multi-dimensio...Reaction kinetics of nanoparticles can be controlled by tuning the Peclet number(Pe)as it is an essential parameter in synthesis of multi-sized nanoparticles.Herein,we propose to implement a self-driven multi-dimension microchannels reactor(MMR)for the one droplet synthesis of multi-sized nanoparticles.By carefully controlling the Pe at the gas-liquid interface,the newly formed seed crystals selectively accumulate and grow to a specific size.By the combination of microchannels of different widths and lengths,one droplet reaction in the same apparatus achieves the synchronous synthesis of diverse nanoparticles.MMR enables precise control of nanoparticle diameter at 5 nm precision in the range of 10-110 nm.The use of MMR can be extended to the synthesis of uniform Ag,Au,Pt,and Pd nanoparticles,opening towards the production and engineering of nanostructured materials.This approach gives the chance to regulate the accumulation probability for precise synthesis of nanoparticles with different diameters.展开更多
To date,fluorescence imaging systems have all relied on at least one beam splitter(BS)to ensure the separation of excitation light and fluorescence.Here,we reported SiO2=TiO2 multi-layer long pass filter integrated Ga...To date,fluorescence imaging systems have all relied on at least one beam splitter(BS)to ensure the separation of excitation light and fluorescence.Here,we reported SiO2=TiO2 multi-layer long pass filter integrated GaN LED.It is considered as the potential source for imaging systems.Experimental results indicate that the GaN LED shows blue emission peaked at 470.3 nm and can be used to excite dye materials.Integrating with a long pass filter(550 nm),the light source can be used to establish a real-time fluorescence detection for dyes that emit light above 550 nm.More interestingly,with this source,a real-time imaging system with signature words written with the dyes,such as‘NJUPT’,can be converted into CCD images.This work may lead to a new strategy for integrating light sources and BS mirrors to build mini and smart fluorescence imaging systems.展开更多
Respiratory infection is the main route for the transmission of coronavirus pneumonia,and the results have shown that the urban spatial environment significantly influences the risk of infection.Based on the Wells-Ril...Respiratory infection is the main route for the transmission of coronavirus pneumonia,and the results have shown that the urban spatial environment significantly influences the risk of infection.Based on the Wells-Riley model of respiratory infection probability,the study determined the human respiratory-related parameters and the effective influence range;extracted urban morphological parameters,assessed the ventilation effects of different spatial environments,and,combined with population flow monitoring data,constructed a method for assessing the risk of Covid-19 respiratory infection in urban-scale grid cells.In the empirical study in Shenyang city,a severe cold region,urban morphological parameters,population size,background wind speed,and individual behavior patterns were used to calculate the distribution characteristics of temporal and spatial concomitant risks in urban areas grids under different scenarios.The results showed that the correlation between the risk of respiratory infection in urban public spaces and the above variables was significant.The exposure time had the greatest degree of influence on the probability of respiratory infection risk among the variables.At the same time,the change in human body spacing beyond 1 m had a minor influence on the risk of infection.Among the urban morphological parameters,building height had the highest correlation with the risk of infection,while building density had the lowest correlation.The actual point distribution of the epidemic in Shenyang from March to April 2022 was used to verify the evaluation results.The overlap rate between medium or higher risk areas and actual cases was 78.55%.The planning strategies for epidemic prevention and control were proposed for the spatial differentiation characteristics of different risk elements.The research results can accurately classify the risk level of urban space and provide a scientific basis for the planning response of epidemic prevention and control and the safety of public activities.展开更多
Micro-nano optomechanical accelerometers are widely used in automobile,aerospace,and other industrial applications.Here,we fabricate mechanical sensing components based on an electrically pumped GaN light-emitting dio...Micro-nano optomechanical accelerometers are widely used in automobile,aerospace,and other industrial applications.Here,we fabricate mechanical sensing components based on an electrically pumped GaN light-emitting diode(LED)with a beam structure.The relationship between the blueshift of the electroluminescence(EL)spectra and the deformation of the GaN beam structure based on the quantum-confined Stark effect(QCSE)of the InGaN quantum well(QW)structure is studied by introducing an extra mass block.Under the equivalent acceleration condition,in addition to the elastic deformation of GaN-LED,a direct relationship exists between the LED’s spectral shift and the acceleration’s magnitude.The extra mass block(gravitational force:7.55×10^(-11)N)induced blueshift of the EL spectra is obtained and shows driven current dependency.A polymer sphere(PS;gravitational force:3.427×10^(-12)N)is placed at the center of the beam GaN-LED,and a blueshift of 0.061 nm is observed in the EL spectrum under the injection current of 0.5 mA.The maximum sensitivity of the acceleration is measured to be 0.02 m∕s^(2),and the maximum measurable acceleration is calculated to be 1.8×10^(6)m∕s^(2).It indicates the simultaneous realization of high sensitivity and a broad acceleration measurement range.This work is significant for several applications,including light force measurement and inertial navigation systems with high integration ability.展开更多
COVID-19 pandemic caused by SARS-CoV-2 infection severely threatens global health and economic development.No effective antiviral drug is currently available to treat COVID-19 and any other human coronavirus infection...COVID-19 pandemic caused by SARS-CoV-2 infection severely threatens global health and economic development.No effective antiviral drug is currently available to treat COVID-19 and any other human coronavirus infections.We report herein that a macrolide antibiotic,carrimycin,potently inhibited the cytopathic effects(CPE)and reduced the levels of viral protein and RNA in multiple cell types infected by human coronavirus 229 E,OC43,and SARS-CoV-2.Time-of-addition and pseudotype virus infection studies indicated that carrimycin inhibited one or multiple post-entry replication events of human coronavirus infection.In support of this notion,metabolic labelling studies showed that carrimycin significantly inhibited the synthesis of viral RNA.Our studies thus strongly suggest that carrimycin is an antiviral agent against a broad-spectrum of human coronaviruses and its therapeutic efficacy to COVID-19 is currently under clinical investigation.展开更多
Collective oscillations of free electrons generate plasmons on the surface of a material. A whispering-gallery microcavity effectively confines the light field on its surface based on the total reflection from its int...Collective oscillations of free electrons generate plasmons on the surface of a material. A whispering-gallery microcavity effectively confines the light field on its surface based on the total reflection from its internal wall. When these two kinds of electromagnetic waves meet each other, the stimulated emissions from an individual ZnO microrod were enhanced more than 50-fold and the threshold was reduced after the whispering-gallery microcavity was coated with a monolayer of graphene and A1 nanoparticles. The improvement of the lasing performance was attributed to the synergistic energy coupling of the graphene/A1 surface plasmons with ZnO excitons. The lasing characteristics and the coupling mechanism were investigated systematically.展开更多
It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers. In this paper, two hexagonal microteeth with varied na...It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers. In this paper, two hexagonal microteeth with varied nanoscaled air-gaps of a ZnO microcomb are used to construct coupled whispering-gallery cavities. This is done to achieve a stable single mode lasing based on Vernier effect without requiring any complicated or sophisticated manipulation to achieve positioning with nanoscale precision. Optical gain and the corresponding ultraviolet lasing performance were improved greatly through coupling with localized surface plasmons of Pt nanoparticles. The ZnO/Pt hybrid microcavities achieved a seven-fold enhancement of intensity of single mode lasing with higher side- mode suppression ratio and lower threshold. The mechanism that led to this enhancement has been described in detail.展开更多
Natural laminar flow technology can significantly reduce aircraft aerodynamic drag and has excellent technical appeal for transport aircraft development with high aerodynamic efficiency.Accurately and efficiently pred...Natural laminar flow technology can significantly reduce aircraft aerodynamic drag and has excellent technical appeal for transport aircraft development with high aerodynamic efficiency.Accurately and efficiently predicting the laminar-to-turbulent transition and revealing the maintenance mechanism of laminar flow in a transport aircraft’s flight environment are significant for developing natural laminar flow wings.In this research,we carry out natural laminar flow flight experiments with different Reynolds numbers and angles of attack.The critical N-factor is calibrated as 9.0 using flight experimental data and linear stability theory from a statistical perspective,which makes sure that the relative error of transition location is within 5%.We then implement a simplified e^(N) transition prediction method with a similar accuracy compared with linear stability theory.We compute the sensitivity information for the simplified eN method with an adjointbased method,using the automatic differentiation technique(ADjoint).The impact of Reynolds numbers and pressure distributions on TS waves is analyzed using the sensitivity information.Through the sensitivity analysis,we find that:favorable pressure gradients not only suppress the development of TS waves but also decrease their sensitivity to Reynolds numbers;there exist three special regions which are very sensitive to the pressure distribution,and the sensitivity decreases as the local favorable pressure gradient increases.The proposed sensitivity analysis method enables robust natural laminar flow wings design.展开更多
Collaborative enhancements from surface plasmons (SPs) and whispering-gallery modes (WGMs) can induce intense near-field effects with high spatial localization around the surface of a semiconducting material. One ...Collaborative enhancements from surface plasmons (SPs) and whispering-gallery modes (WGMs) can induce intense near-field effects with high spatial localization around the surface of a semiconducting material. One can construct a highly efficient hybrid microcavity using semiconducting materials through resonant coupling between SPs and WGMs. Hexagonal ZnO micro-/nanostructures, which have been employed as natural WGM microcavities for ultraviolet (UV) lasing, can be used as ideal platforms to construct such hybrid microcavities. Here, we comprehensively review the recent efforts for improving lasing performance by resonant coupling between SPs and WGMs. Traditional SPs originating from various metals as well as novel SPs originating from atomic layers such as graphene are considered. Moreover, we discuss the mechanism of light-matter interactions beyond the improvements in lasing performance.展开更多
Negative refraction might occur at the interface between a two-dimensional photonic crystal(Ph C)slab and a homogeneous medium,where the guiding of the electromagnetic wave along the third dimension is governed by tot...Negative refraction might occur at the interface between a two-dimensional photonic crystal(Ph C)slab and a homogeneous medium,where the guiding of the electromagnetic wave along the third dimension is governed by total internal reflection.Herein,we report on the observation of negative refraction in the Ph C slab where the vertical guiding is enabled by a bound state in the continuum and essentially beyond the light cone.Such abnormal refraction and guiding mechanism are based on the synchronous crafting of spatial dispersion and the radiative lifetime of Bloch modes within the radiative continuum.Microwave experiments are provided to further validate the numerical proposal in an all-dielectric Ph C platform.It is envisioned that the negative refraction observed beyond the light cone might facilitate the development of optical devices in integrated optics,such as couplers,multiplexers,and demultiplexers.展开更多
Realization of pure and stable ultraviolet electroluminescence(UV EL) of ZnO light-emitting diode(LED)is still a challenging issue, due to complicated defects of intrinsic ZnO and the corresponding device interfaces. ...Realization of pure and stable ultraviolet electroluminescence(UV EL) of ZnO light-emitting diode(LED)is still a challenging issue, due to complicated defects of intrinsic ZnO and the corresponding device interfaces. In this paper, we demonstrated a simple & feasible method to fabricate n-ZnO/AlN/p-GaN heterojunctions light-emitting devices. First, the vertically aligned ZnO nanorods(NRs) have been prepared as high quality active layer, and the nanostructured heterojunction LED arrays were constructed by directly bonding ZnO NRs onto AlN-coated p-GaN wafer. By optimizing the AlN layer thickness to be 20 nm, a strong and pure ultraviolet emission located at 387 nm can be observed. The energy band alignment of n-ZnO/AlN(20 nm)/p-Ga N heterojunction LED has been studied by using X-ray photoelectron spectroscopy(XPS), the valence band offset between AlN and GaN was calculated to be 0.34 eV. On the other side, the conduction band offset(as large as 3.28 eV) between Al N and ZnO can block the flow of electrons from ZnO top-GaN. Thus, electron-hole recombination takes place in the ZnO layer, and a pure UV EL could be observed. Our results provide a significant approach toward future of pure ultraviolet optoelectronic LEDs.展开更多
Microlasers based on high quality (Q) whispering-gallery mode (WGM) resonance are pronfising low threshold laser sources for bio-sensing and imaging applications. In this Letter, dye-doped polymer microspheres wer...Microlasers based on high quality (Q) whispering-gallery mode (WGM) resonance are pronfising low threshold laser sources for bio-sensing and imaging applications. In this Letter, dye-doped polymer microspheres were fabricated by a controlling emulsion solvent evaporation method. WGM lasing with low threshold and high Q factors was realized in an individual microsphere under femtosecond laser pumping. The slight change of environmental relative humidity (RH) can be monitored by measuring the shift of the lasing modes at tile ex- posure of water molecules, which dcmonstrates the sensitivity is as high as 6 pm/RH%. The results would offer an insight into employing microlasers as sensors.展开更多
基金the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20210593)the Foundation of Jiangsu Provincial Double Innovation Doctor Program (Grant No. 30644)+2 种基金the National Natural Science Foundation of China (Grant No. 62204127)State Key Laboratory of Luminescence and Applications (Grant No. SKLA 202104)open research fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications, Ministry of Education)。
文摘Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.
文摘Objective: To report complications related to flap around implants after cochlear implantation, possible causes of such complications and treatments. Methods and material:We performed a retrospective analysis of children in whom complications related to flap around implants occurred after undergoing cochlear implantation in our department from 2005 to 2016. Results:Complications among 1500 cochlear implantation (CI) recipients by the same surgeon included hematoma (n ? 20) and seroma around implants (n ? 15), of which most (n ? 10) recovered in 2 weeks after effective drainage, utility of antibiotics and pressure dressing, but 5 developed flap necrosis and had to undergo contralateral re-implantation. Four patients developed abscess around implants, of whom 2 recovered after 2 weeks of drainage, gentamicin irrigation and use of antibiotics, but 2 patients ended up with flap necrosis and had to receive contralateral reimplantation. Conclusions: Immediate drainage, pressure dressing and antibiotics can be used to effectively control seroma around implants. For seroma lasting for more than two weeks without improvement, surgical drainage may be need.
文摘Objective: A common cavity deformity(CCD) is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity that results in profound hearing loss. There are few studies paying attention to common cavity. Our group is engrossed in observing the improvement of auditory and verbal abilities in children who have received cochlear implantation(CI), and comparing these targets between children with common cavity and normal inner ear structure.Material and methods: A retrospective study was conducted in 12 patients with profound hearing loss that were divided into a common cavity group and a control group, six in each group matched in sex, age and time of implantation, based on inner ear structure. Categories of Auditory Performance(CAP) and speech intelligibility rating(SIR) scores and aided hearing thresholds were collected and compared between the two groups. All patients wore CI for more than 1 year at the Cochlear Center of Anhui Medical University from 2011 to 2015.Results: Postoperative CAP and SIR scores were higher than before operation in both groups(p < 0.05), although the scores were lower in the CCD group than in the control group(p < 0.05). The aided threshold was also lower in the control group than in the CCD group(p < 0.05).Conclusion: Even though audiological improvement in children with CCD was not as good as in those without CCD, CI provides benefits in auditory perception and communication skills in these children.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504264,21802092,51501128,52072005,and 51872279)the Scientific Research Plan Project of Tianjin Municipal Education Commission(Grant No.2017KJ097)
文摘All-inorganic,hole-transporting-layer-free CsPbIBr_(2)perovskite solar cells have great potential for development,but their device performance needs to be further improved.Recently,metal nanostructures have been successfully applied in the field of solar cells to improve their performance.Nano Ag-enhanced power conversion efficiency(PCE)in one CsPbIBr_(2)perovskite solar cell utilizing localized surface plasmons of Ag nanoparticles(NPs)on the surface has been researched experimentally and by simulation in this paper.The localized surface plasmon resonance of Ag NPs has a near-field enhancement effect,which is expected to improve the light absorption of CsPbIBr_(2)perovskite photovoltaic devices.In addition,Ag NPs have a forward-scattering effect on the incident light,which can also improve the performance of CsPbIBr_(2)-based perovskite photovoltaic devices.By directly assembling Ag NPs(with a size of about 150 nm)on the surface of fluorine-doped tin oxide it is found when the particle surface coverage is 10%,the CsPbIBr_(2)perovskite photovoltaic device achieves a best PCE of 2.7%,which is 9.76%higher than that of the control group.Without changing any existing structure in the ready-made solar cell,this facile and efficient method has huge applications.To the best of our knowledge,this paper is the first report on nano Ag-enhanced photoelectric conversion efficiency in this kind of CsPbIBr_(2)perovskite solar cell.
基金supported by State Key Laboratory of Luminescence and Applications(Grant No.SKLA-2021-04)the Foundation of Jiangsu Provincial Double-Innovation Doctor Program(Grant No.30644)+2 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20215093)the Research Start-up Fund(Grant Nos.NY219147 and NY220181)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant Nos.SJCX210267 and SJCX220279)。
文摘Optical gain and loss of microcavity greatly affect the quality of lasing,how to improve optical gain and decrease optical loss is of great significance for the preparation of laser.In this study,four types standard microdisks with different thicknesses of 2.2μm,1.9μm,1.7μm,and 1.45μm were fabricated by micromachining technology process to modulate optical gain and loss of microdisk lasing.The whispering gallery mode lasing in the ultraviolet range of Ga N microdisk devices was investigated for these devices in order to clarify the effect of microdisk thickness on device characteristics.The quality factor Q and lasing mode number for different thicknesses are calculated from the stimulated spectra.The lifetimes of the exciton combination properties of the devices were observed using time-resolved PL spectroscopy.The lasing modes are modulated,and the lifetime decreases,while the Q factor of the devices first increases and then decreases with decreasing thickness.All these results are induced by optical gain and loss competition.
基金supported by the Natural Science Foundation of Jiangsu Province (Nos.BK20210593 and BK20231441)the National Natural Science Foundation of China (No.62204127)the Fundamental Research Funds for the Central Universities (No.NS2022096)。
文摘Using an identical monolithic InGaN/GaN light emitting diode (LED) array as the sensing module and a well-designed data processing module, we demonstrate a small-size concentration sensing prototype. Overlap between the emission and the response spectra of the InGaN/GaN LED makes each pair of LEDs in the arrayed chip form a sensing channel. The changes in liquid concentration can be transformed into variation of photocurrent. The system's sensing properties are further optimized by varying the position, number of receivers, and packaging reflectors. With methyl orange as a tracer agent, the sensing system's resolution is 0.286 μmol/L with a linear measurement region below 40 μmol/L.
基金supported by the National Natural Science Foundation of China(62075041,62375049 and 62335003)the Excellent Postdoctoral Program of Jiangsu Province(2023ZB077)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20210593)the Basic Research Program of Jiangsu Province(BK20222007).
文摘Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matter interactions to laser applications[1].Undergoing decades of development,the improvement of lasing performance is always a significant issue,including low threshold and high quality(Q)factor[2].Increasing optical gain and reducing the losses are the key aspects towards the realization of a high-quality WGM laser.A perfect cavity structure and a smooth surface are the most crucial determinants to reduce optical losses and enhance light field confined abilities.
基金supported by the Beijing Nova Program from Beijing Municipal Science&Technology Commission(Nos.Z201100006820037 and Z211100002121001)the National Key R&D Program of China(No.2018YFA0208501)+3 种基金the National Natural Science Foundation of China(Nos.22075296,91963212,and 51961145102)the Youth Innovation Promotion Association,the Chinese Academy of Sciences(No.2020032)Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202005)F.F.Q.and J.C.acknowledge the Swiss National Super Computing Center(Project No.s1081)for providing the computing support.B.D.C.acknowledges Jiarong Yang for his support in graphing.
文摘Reaction kinetics of nanoparticles can be controlled by tuning the Peclet number(Pe)as it is an essential parameter in synthesis of multi-sized nanoparticles.Herein,we propose to implement a self-driven multi-dimension microchannels reactor(MMR)for the one droplet synthesis of multi-sized nanoparticles.By carefully controlling the Pe at the gas-liquid interface,the newly formed seed crystals selectively accumulate and grow to a specific size.By the combination of microchannels of different widths and lengths,one droplet reaction in the same apparatus achieves the synchronous synthesis of diverse nanoparticles.MMR enables precise control of nanoparticle diameter at 5 nm precision in the range of 10-110 nm.The use of MMR can be extended to the synthesis of uniform Ag,Au,Pt,and Pd nanoparticles,opening towards the production and engineering of nanostructured materials.This approach gives the chance to regulate the accumulation probability for precise synthesis of nanoparticles with different diameters.
基金supported by the National Natural Science Foundation of China(Nos.62004103,61827804,and 62005130)the Natural Science Foundation of Jiangsu Province(Nos.BK20200755,BK20210593,and BK20200743)+4 种基金the“111”Project(No.D17018)the NUPTSF(No.NY220118)the STCSM(No.SKLSFO2020-04)the Foundation of Jiangsu Provincial Double-Innovation Doctor Program(No.30644)the Start-up Fund(Nos.NY219147 and NY220181).
文摘To date,fluorescence imaging systems have all relied on at least one beam splitter(BS)to ensure the separation of excitation light and fluorescence.Here,we reported SiO2=TiO2 multi-layer long pass filter integrated GaN LED.It is considered as the potential source for imaging systems.Experimental results indicate that the GaN LED shows blue emission peaked at 470.3 nm and can be used to excite dye materials.Integrating with a long pass filter(550 nm),the light source can be used to establish a real-time fluorescence detection for dyes that emit light above 550 nm.More interestingly,with this source,a real-time imaging system with signature words written with the dyes,such as‘NJUPT’,can be converted into CCD images.This work may lead to a new strategy for integrating light sources and BS mirrors to build mini and smart fluorescence imaging systems.
基金supported by the General Program of National Natural Science Foundation of China(No.51978421)。
文摘Respiratory infection is the main route for the transmission of coronavirus pneumonia,and the results have shown that the urban spatial environment significantly influences the risk of infection.Based on the Wells-Riley model of respiratory infection probability,the study determined the human respiratory-related parameters and the effective influence range;extracted urban morphological parameters,assessed the ventilation effects of different spatial environments,and,combined with population flow monitoring data,constructed a method for assessing the risk of Covid-19 respiratory infection in urban-scale grid cells.In the empirical study in Shenyang city,a severe cold region,urban morphological parameters,population size,background wind speed,and individual behavior patterns were used to calculate the distribution characteristics of temporal and spatial concomitant risks in urban areas grids under different scenarios.The results showed that the correlation between the risk of respiratory infection in urban public spaces and the above variables was significant.The exposure time had the greatest degree of influence on the probability of respiratory infection risk among the variables.At the same time,the change in human body spacing beyond 1 m had a minor influence on the risk of infection.Among the urban morphological parameters,building height had the highest correlation with the risk of infection,while building density had the lowest correlation.The actual point distribution of the epidemic in Shenyang from March to April 2022 was used to verify the evaluation results.The overlap rate between medium or higher risk areas and actual cases was 78.55%.The planning strategies for epidemic prevention and control were proposed for the spatial differentiation characteristics of different risk elements.The research results can accurately classify the risk level of urban space and provide a scientific basis for the planning response of epidemic prevention and control and the safety of public activities.
基金National Natural Science Foundation of China(62204127)Postgraduate Research Practice Innovation Program of Jiangsu Province(SJCX21_0267)+4 种基金Research Start-up Fund(NY219147,NY220181)Natural Science Foundation of Jiangsu Province(BK20215093)Foundation of Jiangsu Provincial Double-Innovation Doctor Program(30644)China Postdoctoral Science Foundation(2018M630588,2020M671441)State Key Laboratory of Luminescence and Applications(SKLA-2021-04)。
文摘Micro-nano optomechanical accelerometers are widely used in automobile,aerospace,and other industrial applications.Here,we fabricate mechanical sensing components based on an electrically pumped GaN light-emitting diode(LED)with a beam structure.The relationship between the blueshift of the electroluminescence(EL)spectra and the deformation of the GaN beam structure based on the quantum-confined Stark effect(QCSE)of the InGaN quantum well(QW)structure is studied by introducing an extra mass block.Under the equivalent acceleration condition,in addition to the elastic deformation of GaN-LED,a direct relationship exists between the LED’s spectral shift and the acceleration’s magnitude.The extra mass block(gravitational force:7.55×10^(-11)N)induced blueshift of the EL spectra is obtained and shows driven current dependency.A polymer sphere(PS;gravitational force:3.427×10^(-12)N)is placed at the center of the beam GaN-LED,and a blueshift of 0.061 nm is observed in the EL spectrum under the injection current of 0.5 mA.The maximum sensitivity of the acceleration is measured to be 0.02 m∕s^(2),and the maximum measurable acceleration is calculated to be 1.8×10^(6)m∕s^(2).It indicates the simultaneous realization of high sensitivity and a broad acceleration measurement range.This work is significant for several applications,including light force measurement and inertial navigation systems with high integration ability.
基金financially supported by CAMS Initiative for Innovative Medicine(2020-I2M-Co V19-008,China)the National Science and Technology Major Projects for“Major New Drugs Innovation and Development”(2018ZX09711003,China)+1 种基金the National Key Research and Development Program of China(2020YFC0844900,China)Fundamental Research Funds for CAMS of China(2020HY320001,China)
文摘COVID-19 pandemic caused by SARS-CoV-2 infection severely threatens global health and economic development.No effective antiviral drug is currently available to treat COVID-19 and any other human coronavirus infections.We report herein that a macrolide antibiotic,carrimycin,potently inhibited the cytopathic effects(CPE)and reduced the levels of viral protein and RNA in multiple cell types infected by human coronavirus 229 E,OC43,and SARS-CoV-2.Time-of-addition and pseudotype virus infection studies indicated that carrimycin inhibited one or multiple post-entry replication events of human coronavirus infection.In support of this notion,metabolic labelling studies showed that carrimycin significantly inhibited the synthesis of viral RNA.Our studies thus strongly suggest that carrimycin is an antiviral agent against a broad-spectrum of human coronaviruses and its therapeutic efficacy to COVID-19 is currently under clinical investigation.
文摘Collective oscillations of free electrons generate plasmons on the surface of a material. A whispering-gallery microcavity effectively confines the light field on its surface based on the total reflection from its internal wall. When these two kinds of electromagnetic waves meet each other, the stimulated emissions from an individual ZnO microrod were enhanced more than 50-fold and the threshold was reduced after the whispering-gallery microcavity was coated with a monolayer of graphene and A1 nanoparticles. The improvement of the lasing performance was attributed to the synergistic energy coupling of the graphene/A1 surface plasmons with ZnO excitons. The lasing characteristics and the coupling mechanism were investigated systematically.
基金Acknowledgements The authors sincerely appreciate the help of Shufeng Wang and Yu Li at Peking University and Andong Xia at Institute of Chemistry Chinese Academy of Sciences for their technical support on time-resolved PL. This work was supported by the National Basic Research Program (No. 2013CB932903), National Natural Science Foundation (Nos. 61275054, 61475035, and 11404289), Jiangsu Province Science and Technology Support Program (No. BE2016177) and Natural Science Foundation of Zhejiang Province (No. LY17A040011).
文摘It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers. In this paper, two hexagonal microteeth with varied nanoscaled air-gaps of a ZnO microcomb are used to construct coupled whispering-gallery cavities. This is done to achieve a stable single mode lasing based on Vernier effect without requiring any complicated or sophisticated manipulation to achieve positioning with nanoscale precision. Optical gain and the corresponding ultraviolet lasing performance were improved greatly through coupling with localized surface plasmons of Pt nanoparticles. The ZnO/Pt hybrid microcavities achieved a seven-fold enhancement of intensity of single mode lasing with higher side- mode suppression ratio and lower threshold. The mechanism that led to this enhancement has been described in detail.
基金supported by the National Natural Science Foundation of China(No.12002284)。
文摘Natural laminar flow technology can significantly reduce aircraft aerodynamic drag and has excellent technical appeal for transport aircraft development with high aerodynamic efficiency.Accurately and efficiently predicting the laminar-to-turbulent transition and revealing the maintenance mechanism of laminar flow in a transport aircraft’s flight environment are significant for developing natural laminar flow wings.In this research,we carry out natural laminar flow flight experiments with different Reynolds numbers and angles of attack.The critical N-factor is calibrated as 9.0 using flight experimental data and linear stability theory from a statistical perspective,which makes sure that the relative error of transition location is within 5%.We then implement a simplified e^(N) transition prediction method with a similar accuracy compared with linear stability theory.We compute the sensitivity information for the simplified eN method with an adjointbased method,using the automatic differentiation technique(ADjoint).The impact of Reynolds numbers and pressure distributions on TS waves is analyzed using the sensitivity information.Through the sensitivity analysis,we find that:favorable pressure gradients not only suppress the development of TS waves but also decrease their sensitivity to Reynolds numbers;there exist three special regions which are very sensitive to the pressure distribution,and the sensitivity decreases as the local favorable pressure gradient increases.The proposed sensitivity analysis method enables robust natural laminar flow wings design.
文摘Collaborative enhancements from surface plasmons (SPs) and whispering-gallery modes (WGMs) can induce intense near-field effects with high spatial localization around the surface of a semiconducting material. One can construct a highly efficient hybrid microcavity using semiconducting materials through resonant coupling between SPs and WGMs. Hexagonal ZnO micro-/nanostructures, which have been employed as natural WGM microcavities for ultraviolet (UV) lasing, can be used as ideal platforms to construct such hybrid microcavities. Here, we comprehensively review the recent efforts for improving lasing performance by resonant coupling between SPs and WGMs. Traditional SPs originating from various metals as well as novel SPs originating from atomic layers such as graphene are considered. Moreover, we discuss the mechanism of light-matter interactions beyond the improvements in lasing performance.
基金National Key Research and Development Program of China(2018YFB1801001)National Natural Science Foundation of China(91750110)+2 种基金Guangdong Introducing Innovative and Entrepreneurial Teams of the Pearl River Talent Recruitment Program(2019ZT08X340)Research and Development Plan in Key Areas of Guangdong Province(2018B010114002)Pearl River Nova Program of Guangzhou(201806010040)。
文摘Negative refraction might occur at the interface between a two-dimensional photonic crystal(Ph C)slab and a homogeneous medium,where the guiding of the electromagnetic wave along the third dimension is governed by total internal reflection.Herein,we report on the observation of negative refraction in the Ph C slab where the vertical guiding is enabled by a bound state in the continuum and essentially beyond the light cone.Such abnormal refraction and guiding mechanism are based on the synchronous crafting of spatial dispersion and the radiative lifetime of Bloch modes within the radiative continuum.Microwave experiments are provided to further validate the numerical proposal in an all-dielectric Ph C platform.It is envisioned that the negative refraction observed beyond the light cone might facilitate the development of optical devices in integrated optics,such as couplers,multiplexers,and demultiplexers.
基金supported by the National Natural Science Foundation of China(61475035,11734005)the Science and Technology Support Program of Jiangsu Province(BE2016177)the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘Realization of pure and stable ultraviolet electroluminescence(UV EL) of ZnO light-emitting diode(LED)is still a challenging issue, due to complicated defects of intrinsic ZnO and the corresponding device interfaces. In this paper, we demonstrated a simple & feasible method to fabricate n-ZnO/AlN/p-GaN heterojunctions light-emitting devices. First, the vertically aligned ZnO nanorods(NRs) have been prepared as high quality active layer, and the nanostructured heterojunction LED arrays were constructed by directly bonding ZnO NRs onto AlN-coated p-GaN wafer. By optimizing the AlN layer thickness to be 20 nm, a strong and pure ultraviolet emission located at 387 nm can be observed. The energy band alignment of n-ZnO/AlN(20 nm)/p-Ga N heterojunction LED has been studied by using X-ray photoelectron spectroscopy(XPS), the valence band offset between AlN and GaN was calculated to be 0.34 eV. On the other side, the conduction band offset(as large as 3.28 eV) between Al N and ZnO can block the flow of electrons from ZnO top-GaN. Thus, electron-hole recombination takes place in the ZnO layer, and a pure UV EL could be observed. Our results provide a significant approach toward future of pure ultraviolet optoelectronic LEDs.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61275054)the Science and Technology Support Program of Jiangsu Province(No.BE2016177)"Collaborative Innovation Center of Suzhou Nano Science and Technology" for their support
文摘Microlasers based on high quality (Q) whispering-gallery mode (WGM) resonance are pronfising low threshold laser sources for bio-sensing and imaging applications. In this Letter, dye-doped polymer microspheres were fabricated by a controlling emulsion solvent evaporation method. WGM lasing with low threshold and high Q factors was realized in an individual microsphere under femtosecond laser pumping. The slight change of environmental relative humidity (RH) can be monitored by measuring the shift of the lasing modes at tile ex- posure of water molecules, which dcmonstrates the sensitivity is as high as 6 pm/RH%. The results would offer an insight into employing microlasers as sensors.