White Hypsizygus marmoreus is a popular edible mushroom.Its mycelium is easy to be contaminated by Penicillium,which leads to a decrease in its quality and yield.Penicillium could compete for limited space and nutrien...White Hypsizygus marmoreus is a popular edible mushroom.Its mycelium is easy to be contaminated by Penicillium,which leads to a decrease in its quality and yield.Penicillium could compete for limited space and nutrients through rapid growth and produce a variety of harmful gases,such as benzene,aldehydes,phenols,etc.,to inhibit the growth of H.marmoreus mycelium.A series of changes occurred in H.marmoreus proteome after contamination when detected by the label-free tandem mass spectrometry(MS/MS)technique.Some proteins with up-regulated expression worked together to participate in some processes,such as the non-toxic transformation of harmful gases,glutathione metabolism,histone modification,nucleotide excision repair,clearing misfolded proteins,and synthesizing glutamine,which were mainly used in response to biological stress.The proteins with down-regulated expression are mainly related to the processes of ribosome function,protein processing,spliceosome,carbon metabolism,glycolysis,and gluconeogenesis.The reduction in the function of these proteins affected the production of the cell components,which might be an adjustment to adapt to growth retardation.This study further enhanced the understanding of the biological stress response and the growth restriction adaptation mechanisms in edible fungi.It also provided a theoretical basis for protein function exploration and edible mushroom food safety research.展开更多
Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro...Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.展开更多
Objective:To examine differences in outcomes of semi-rigid ureteroscopy(URS)with or without a modified-ureteral-access-sheath(mUAS)to treat large upper ureteral stones.Methods:Patients with single,radio-opaque large u...Objective:To examine differences in outcomes of semi-rigid ureteroscopy(URS)with or without a modified-ureteral-access-sheath(mUAS)to treat large upper ureteral stones.Methods:Patients with single,radio-opaque large upper ureteral stone(≥10 mm)treated using semi-rigid URS between August 2013 and October 2016 were retrospectively evaluated.The stone-free status was determined from Kidney-ureter-bladder(KUB)X-ray films taken on postoperative Day 1 and after 1 month.Results:Of 103 patients meeting inclusion criteria,43(41.75%)and 60(58.25%)were treated with semi-rigid URS with and without mUAS,respectively.The immediate stone-free rate(SFR)for the mUAS group was significantly higher than the non-mUAS group(40[93.0%]vs.46[76.7%];p=0.033).The SFR at 1 month was also high for patients treated using mUAS,but not statistically different from patients not treated with mUAS(41[95.3%]mUAS vs.51[85.0%]non-mUAS;p=0.115).Auxiliary procedure rates were significantly lower for mUAS patients compared to non-mUAS patients(2[4.7%]vs.14[23.3%];p=0.01).There were no significant differences in surgical duration and hospital stays,and the overall complication rates were statistically similar for mUAS patients compared to non-mUAS patients(1[2.3%]vs.3[5.0%];p=0.638).展开更多
Panax L.(Araliaceae) has a long history of medicinal and edible use due to its significant tonifying effects,and ginseng research has been a hot topic in natural products research and food science. In continuation of ...Panax L.(Araliaceae) has a long history of medicinal and edible use due to its significant tonifying effects,and ginseng research has been a hot topic in natural products research and food science. In continuation of our recent ginseng review, we highlighted the advances in ginseng research from 2021 to 2023 with 157 citations, which exhibited the increasingly systematic, collaborative, and intelligent characteristics.In this review, we firstly updated the progress in phytochemistry involving the ginsenosides and polysaccharides and summarized the researches on the active components. Then, some specific applications by feat of the multidimensional chromatography, mass spectrometry imaging, DNA barcoding, and metabolomics, were analyzed, which could provide rich information supporting the multi-component characterization, authentication, and quality control of ginseng and the versatile products. Finally, the recent biosynthesis studies concerning ginsenosides were retrospected. Additionally, the current challenges and future trends with respect to ginseng research were discussed.展开更多
The ultra-low NOx emission requirement(50 mg/m^(3))brings great challenge to CFB boilers in China.To further tap the NOx abatement potential,full understanding the fundamentals behind CFB boilers is needed.To achieve ...The ultra-low NOx emission requirement(50 mg/m^(3))brings great challenge to CFB boilers in China.To further tap the NOx abatement potential,full understanding the fundamentals behind CFB boilers is needed.To achieve this,a comprehensive CPFD model is established and verified;gas-solid flow,combustion,and NOx emission behavior in an industrial CFB boiler are elaborated;influences of primary air volume and coal particle size on furnace performance are evaluated.Simulation results indicate that there exists a typical core-annular flow structure in the boiler furnace.Furnace temperature is highest in the bottom dense-phase zone(about 950℃)and decreases gradually along the furnace height.Oxygen-deficient combustion results in high CO concentration and strong reducing atmosphere in the lower furnace.NOx concentration gradually increases in the bottom furnace,reaches maximum at the elevation of secondary air inlet,and then decreases slightly in the upper furnace.Appropriate decreasing the primary air volume and coal particle size would increase the CO concentration and intensify the in-furnace reducing atmosphere,which favors for NOx reduction and low NOx emission from CFB boilers.展开更多
A nanowire (NW) structure provides an alternative scheme for deep ultraviolet light emitting diodes (DUV-LEDs) that promises high material quality and better light extraction efficiency (LEE). In this report, we...A nanowire (NW) structure provides an alternative scheme for deep ultraviolet light emitting diodes (DUV-LEDs) that promises high material quality and better light extraction efficiency (LEE). In this report, we investigate the influence of the tapering angle of closely packed AIGaN NWs, which is found to exist naturally in molecular beam epitaxy (MBE) grown NW structures, on the LEE of NW DUV-LEDs. It is observed that, by having a small tapering angle, the vertical extraction is greatly enhanced for both transverse magnetic (TM) and transverse elec- tric (TE) polarizations. Most notably, the vertical extraction of TM emission increased from 4.8% to 24.3%, which makes the LEE reasonably large to achieve high-performance DUV-LEDs. This is because the breaking of symmetry in the vertical direction changes the propagation of the light significantly to allow more coupling into radiation modes. Finally, we introduce errors to the NW positions to show the advantages of the tapered NW structures can be projected to random closely packed NW arrays. The results obtained in this paper can provide guidelines for designing efficient NW DUV-LEDs.展开更多
A novel method for the synthesis of zeolite was developed in this paper. The synthesis was carried out by hydrothermal activation after alkali fusion and coal fly ash (CFA) was used as raw material with seawater of ...A novel method for the synthesis of zeolite was developed in this paper. The synthesis was carried out by hydrothermal activation after alkali fusion and coal fly ash (CFA) was used as raw material with seawater of different salinities. Seawater salinity was varied from 32 to 88 for zeolite crystallization during the hydrothermal process. The results show that seawater salinity plays an important role in zeolite synthesis with CFA during hydrothermal treatment. The products were a mixture of NaX zeolite and hydroxysodalite; seawater salinity more strongly affected the crystallization than the type and chemical composition of the zeolites. The yield of CFA transformed into zeolite gradually rose with the increase in salinity, reaching a transformation rate of 48%--62% as the salinity increased from 32 to 88, respectively. The proposed method allows for the efficient disposal of by-products; therefore, the application of seawater in zeolite synthesis presents promising economic and ecological benefits.展开更多
We report on the carrier dynamic and electronic structure investigations on AlGaN-based deep-ultraviolet multiple quantum wells (MQWs)with lateral polarity domains.The localized potential maximum is predicted near the...We report on the carrier dynamic and electronic structure investigations on AlGaN-based deep-ultraviolet multiple quantum wells (MQWs)with lateral polarity domains.The localized potential maximum is predicted near the domain boundaries by first-principle calculation,suggesting carrier localization and efficient radiative recombination.More importantly,lateral band diagrams of the MQWs are proposed based on electron affinities and valance band levels calculated from ultraviolet(UV)photoelectron spectroscopy.The proposed lateral band diagram is further demonstrated by surface potential distribution collected by Kelvin probe microscopy and the density-of-state calculation of energy bands.This work illustrates that lateral polarity structures are playing essential roles in the electronic properties of II nitride photonic devices and may provide novel perspective in the realization of high-efficiency UV emitters.展开更多
Surface potentials in the vicinity of V-pits(cone bottom) and U-pits(blunt bottom) on epitaxial GaN surface have been systematically studied using ultraviolet(UV) light-assisted Kelvin probe force microscopy(KPFM). Th...Surface potentials in the vicinity of V-pits(cone bottom) and U-pits(blunt bottom) on epitaxial GaN surface have been systematically studied using ultraviolet(UV) light-assisted Kelvin probe force microscopy(KPFM). The band structure models are established to understand variation of the surface potentials at the pits and planar surface with and without UV light. The photo-generated carrier behavior at the pit defects is studied. According to the surface potential results, it can be deduced that the carrier distributions around the V-and U-pits are uneven. In dark, the electron concentration at the bottom of V-pit(30 n_0) and Upit(15 n_0) are higher than that at planar surface(n_0). Under UV light, for V-pit, the electron concentration at the cone bottom(4.93×10^(11) n_0) is lower than that at the surrounding planar surface(5.68×10^(13) n_0). For U-pit, the electron concentration at the blunt bottom is 1.35×10^(12) n_0, which is lower than that at the surrounding planar surface(6.13×10^(13) n_0). The non-equilibrium electron concentrations at different locations are calculated. Based on the non-equilibrium electron concentration, it can be concluded that the carrier recombination rate at pit defects is higher than that at planar surface.展开更多
The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer's disease (A...The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer's disease (AD) treatment as an inhibitor of PS1/BACE1 interaction. 3-a-Akebonoic acid, which emanated from a high throughput screening (HTS), was discovered to interfere with P S 1/BACE 1 interaction and reduce amyloid β-protein (Aβ) production. In view of the limited source, we instead used naturally rich betulinic acid (compound 2) as starting material for lead optimization and a focused library of its derivatives was constructed to gain a better understanding of the structure activity relationship (SAR) of triterpenoid-type inhibitor of PS1/BACE1 interaction. Compound 22 was finally chosen as the most potent PS 1/BACE 1 interaction inhibitor, which reduced Aβgeneration effectively.展开更多
The traditional plasma etching process for defining micro-LED pixels could lead to significant sidewall damage.Defects near sidewall regions act as non-radiative recombination centers and paths for current leakage,sig...The traditional plasma etching process for defining micro-LED pixels could lead to significant sidewall damage.Defects near sidewall regions act as non-radiative recombination centers and paths for current leakage,significantly deteriorating device performance.In this study,we demonstrated a novel selective thermal oxidation(STO)method that allowed pixel definition without undergoing plasma damage and subsequent dielectric passivation.Thermal annealing in ambient air oxidized and reshaped the LED structure,such as p-layers and InGaN/GaN multiple quantum wells.Simultaneously,the pixel areas beneath the pre-deposited SiO_(2)layer were selectively and effectively protected.It was demonstrated that prolonged thermal annealing time enhanced the insulating properties of the oxide,significantly reducing LED leakage current.Furthermore,applying a thicker SiO_(2)protective layer minimized device resistance and boosted device efficiency effectively.Utilizing the STO method,InGaN green micro-LED arrays with 50-,30-,and 10-μm pixel sizes were manufactured and characterized.The results indicated that after 4 h of air annealing and with a 3.5-μm SiO_(2)protective layer,the 10-μm pixel array exhibited leakage currents density 1.2×10^(-6)A/cm^(2)at-10 V voltage and a peak on-wafer external quantum efficiency of~6.48%.This work suggests that the STO method could become an effective approach for future micro-LED manufacturing to mitigate adverse LED efficiency size effects due to the plasma etching and improve device efficiency.Micro-LEDs fabricated through the STO method can be applied to micro-displays,visible light communication,and optical interconnect-based memories.Almost planar pixel geometry will provide more possibilities for the monolithic integration of driving circuits with micro-LEDs.Moreover,the STO method is not limited to micro-LED fabrication and can be extended to design other III-nitride devices,such as photodetectors,laser diodes,high-electron-mobility transistors,and Schottky barrier diodes.展开更多
We demonstrate a neural network capable of designing on-demand multiple symmetry-protected bound states in the continuum(BICs)in freeform structures with predefined symmetry.The latent representation of the freeform s...We demonstrate a neural network capable of designing on-demand multiple symmetry-protected bound states in the continuum(BICs)in freeform structures with predefined symmetry.The latent representation of the freeform structures allows the tuning of the geometry in a differentiable,continuous way.We show the rich band inversion and accidental degeneracy in these freeform structures by interacting with the latent representation directly.Moreover,a high design accuracy is demonstrated for arbitrary control of multiple BIC frequencies by using a photonic property readout network to interpret the latent representation.展开更多
Connected-annular-rods photonic crystals(CARPCs) in both triangular and square lattices are proposed to enhance the two-dimensional complete photonic bandgap(CPBG) for chalcogenide material systems with moderate refra...Connected-annular-rods photonic crystals(CARPCs) in both triangular and square lattices are proposed to enhance the two-dimensional complete photonic bandgap(CPBG) for chalcogenide material systems with moderate refractive index contrast. For the typical chalcogenide-glass–air system with an index contrast of 2.8:1, the optimized square lattice CARPC exhibits a significantly larger normalized CPBG of about 13.50%, though the use of triangular lattice CARPC is unable to enhance the CPBG. It is almost twice as large as our previously reported result [IEEE J. Sel. Top. Quantum Electron. 22, 4900108(2016)]. Moreover, the CPBG of the square-lattice CARPC could remain until an index contrast as low as 2.24:1. The result not only favors wideband CPBG applications for index contrast systems near 2.8:1, but also makes various optical applications that are dependent on CPBG possible for more widely refractive index contrast systems.展开更多
Wide-bandgap semiconductors exhibit much larger energybandgaps than traditional semiconductors such as silicon,rendering them very promising to be applied in the fields of electronics and optoelectronics.Prominent exa...Wide-bandgap semiconductors exhibit much larger energybandgaps than traditional semiconductors such as silicon,rendering them very promising to be applied in the fields of electronics and optoelectronics.Prominent examples of semiconductors include SiC,GaN,ZnO,and diamond,which exhibitdistinctive characteristics such as elevated mobility and thermalconductivity.These characteristics facilitate the operation of awide range of devices,including energy-efficient bipolar junctiontransistors(BJTs)and metal-oxide-semiconductor field-effecttransistors(MOSFETs),as well as high-frequency high-electronmobility transistors(HEMTs)and optoelectronic components suchas light-emitting diodes(LEDs)and lasers.These semiconductorsare used in building integrated circuits(ICs)to facilitate theoperation of power electronics,computer devices,RF systems,andother optoelectronic advancements.These breakthroughs includevarious applications such as imaging,optical communication,andsensing.Among them,the field of power electronics has witnessedtremendous progress in recent years with the development of widebandgap(WBG)semiconductor devices,which is capable ofswitching large currents and voltages rapidly with low losses.However,it has been proven challenging to integrate these deviceswith silicon complementary metal oxide semiconductor(CMOS)logic circuits required for complex control functions.The monolithic integration of silicon CMOS with WBG devices increases thecomplexity of fabricating monolithically integrated smart integrated circuits(ICs).This review article proposes implementingCMOS logic directly on the WBG platform as a solution.However,achieving the CMOS functionalities with the adoption of WBGmaterials still remains a significant hurdle.This article summarizesthe research progress in the fabrication of integrated circuitsadopting various WBG materials ranging from SiC to diamond,with the goal of building future smart power ICs.展开更多
Semiconductor UV photonics research has emerged as one of the most heavily invested areas among semiconductor photonics research due to numerous crucial applications such as sterilization,sensing,curing,and communicat...Semiconductor UV photonics research has emerged as one of the most heavily invested areas among semiconductor photonics research due to numerous crucial applications such as sterilization,sensing,curing,and communication.The feature issue disseminates nine timely original research and two review papers from leading research groups and companies,covering most frontiers of the semiconductor UV photonics research,from epitaxy,device physics and design,nanostructures,fabrication,packaging,reliability,and application for light-emitting diodes,laser diodes,and photodetectors.展开更多
基金funded by the Shandong Provincial Natural Science Foundation,China (ZR2020QC005)the National Natural Science Foundation of China (32272789)+3 种基金the National Natural Science Foundation of China (32000041)the Shandong Edible Fungus Agricultural Technology System (SDAIT-07-02)the Shandong Provincial Key Research and Development Plan (2021ZDSYS28)the Qingdao Agricultural University Scientific Research Foundation (6631120076)。
文摘White Hypsizygus marmoreus is a popular edible mushroom.Its mycelium is easy to be contaminated by Penicillium,which leads to a decrease in its quality and yield.Penicillium could compete for limited space and nutrients through rapid growth and produce a variety of harmful gases,such as benzene,aldehydes,phenols,etc.,to inhibit the growth of H.marmoreus mycelium.A series of changes occurred in H.marmoreus proteome after contamination when detected by the label-free tandem mass spectrometry(MS/MS)technique.Some proteins with up-regulated expression worked together to participate in some processes,such as the non-toxic transformation of harmful gases,glutathione metabolism,histone modification,nucleotide excision repair,clearing misfolded proteins,and synthesizing glutamine,which were mainly used in response to biological stress.The proteins with down-regulated expression are mainly related to the processes of ribosome function,protein processing,spliceosome,carbon metabolism,glycolysis,and gluconeogenesis.The reduction in the function of these proteins affected the production of the cell components,which might be an adjustment to adapt to growth retardation.This study further enhanced the understanding of the biological stress response and the growth restriction adaptation mechanisms in edible fungi.It also provided a theoretical basis for protein function exploration and edible mushroom food safety research.
基金National Natural Science Foundation of China(Grant No.81872996)Natural Science Foundation of Tianjin of China(Grant No.20JCYBJC00060).
文摘Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.
基金This work was financed by grants from the National Natural Science Foundation of China(No.81370804 and No.81670643)Guangzhou Science,Technology and Innovation Commission(No.201604020001,No.201607010162 and No.201704020193).
文摘Objective:To examine differences in outcomes of semi-rigid ureteroscopy(URS)with or without a modified-ureteral-access-sheath(mUAS)to treat large upper ureteral stones.Methods:Patients with single,radio-opaque large upper ureteral stone(≥10 mm)treated using semi-rigid URS between August 2013 and October 2016 were retrospectively evaluated.The stone-free status was determined from Kidney-ureter-bladder(KUB)X-ray films taken on postoperative Day 1 and after 1 month.Results:Of 103 patients meeting inclusion criteria,43(41.75%)and 60(58.25%)were treated with semi-rigid URS with and without mUAS,respectively.The immediate stone-free rate(SFR)for the mUAS group was significantly higher than the non-mUAS group(40[93.0%]vs.46[76.7%];p=0.033).The SFR at 1 month was also high for patients treated using mUAS,but not statistically different from patients not treated with mUAS(41[95.3%]mUAS vs.51[85.0%]non-mUAS;p=0.115).Auxiliary procedure rates were significantly lower for mUAS patients compared to non-mUAS patients(2[4.7%]vs.14[23.3%];p=0.01).There were no significant differences in surgical duration and hospital stays,and the overall complication rates were statistically similar for mUAS patients compared to non-mUAS patients(1[2.3%]vs.3[5.0%];p=0.638).
基金financially supported by National Key R&D Program of China (No. 2022YFC3501805)National Natural Science Foundation of China (No. 82374030)+3 种基金Tianjin Committee of Science and Technology of China (No. 23ZYJDSS00030)China Postdoctoral Science Foundation-Tianjin Joint Support Program (No. 2023T030TJ)Foundation of State Key Laboratory of Componentbased Chinese Medicine (No. CBQM2022103 and No. CBCM2023202)Tianjin Outstanding Youth Fund (No. 23JCJQJC00030)。
文摘Panax L.(Araliaceae) has a long history of medicinal and edible use due to its significant tonifying effects,and ginseng research has been a hot topic in natural products research and food science. In continuation of our recent ginseng review, we highlighted the advances in ginseng research from 2021 to 2023 with 157 citations, which exhibited the increasingly systematic, collaborative, and intelligent characteristics.In this review, we firstly updated the progress in phytochemistry involving the ginsenosides and polysaccharides and summarized the researches on the active components. Then, some specific applications by feat of the multidimensional chromatography, mass spectrometry imaging, DNA barcoding, and metabolomics, were analyzed, which could provide rich information supporting the multi-component characterization, authentication, and quality control of ginseng and the versatile products. Finally, the recent biosynthesis studies concerning ginsenosides were retrospected. Additionally, the current challenges and future trends with respect to ginseng research were discussed.
基金The authors acknowledge the support from the National Natural Science Foundation of China(grant No.22178095)。
文摘The ultra-low NOx emission requirement(50 mg/m^(3))brings great challenge to CFB boilers in China.To further tap the NOx abatement potential,full understanding the fundamentals behind CFB boilers is needed.To achieve this,a comprehensive CPFD model is established and verified;gas-solid flow,combustion,and NOx emission behavior in an industrial CFB boiler are elaborated;influences of primary air volume and coal particle size on furnace performance are evaluated.Simulation results indicate that there exists a typical core-annular flow structure in the boiler furnace.Furnace temperature is highest in the bottom dense-phase zone(about 950℃)and decreases gradually along the furnace height.Oxygen-deficient combustion results in high CO concentration and strong reducing atmosphere in the lower furnace.NOx concentration gradually increases in the bottom furnace,reaches maximum at the elevation of secondary air inlet,and then decreases slightly in the upper furnace.Appropriate decreasing the primary air volume and coal particle size would increase the CO concentration and intensify the in-furnace reducing atmosphere,which favors for NOx reduction and low NOx emission from CFB boilers.
基金King Abdullah University of Science and Technology(KAUST)(KAUST Baseline Fund BAS/1/1614-01-01,KAUST Baseline Fund BAS/1/1664-01-01,KAUST Equipment Fund BAS/1/1664-01-07)National Natural Science Foundation of China(NSFC)(61774065)
文摘A nanowire (NW) structure provides an alternative scheme for deep ultraviolet light emitting diodes (DUV-LEDs) that promises high material quality and better light extraction efficiency (LEE). In this report, we investigate the influence of the tapering angle of closely packed AIGaN NWs, which is found to exist naturally in molecular beam epitaxy (MBE) grown NW structures, on the LEE of NW DUV-LEDs. It is observed that, by having a small tapering angle, the vertical extraction is greatly enhanced for both transverse magnetic (TM) and transverse elec- tric (TE) polarizations. Most notably, the vertical extraction of TM emission increased from 4.8% to 24.3%, which makes the LEE reasonably large to achieve high-performance DUV-LEDs. This is because the breaking of symmetry in the vertical direction changes the propagation of the light significantly to allow more coupling into radiation modes. Finally, we introduce errors to the NW positions to show the advantages of the tapered NW structures can be projected to random closely packed NW arrays. The results obtained in this paper can provide guidelines for designing efficient NW DUV-LEDs.
文摘A novel method for the synthesis of zeolite was developed in this paper. The synthesis was carried out by hydrothermal activation after alkali fusion and coal fly ash (CFA) was used as raw material with seawater of different salinities. Seawater salinity was varied from 32 to 88 for zeolite crystallization during the hydrothermal process. The results show that seawater salinity plays an important role in zeolite synthesis with CFA during hydrothermal treatment. The products were a mixture of NaX zeolite and hydroxysodalite; seawater salinity more strongly affected the crystallization than the type and chemical composition of the zeolites. The yield of CFA transformed into zeolite gradually rose with the increase in salinity, reaching a transformation rate of 48%--62% as the salinity increased from 32 to 88, respectively. The proposed method allows for the efficient disposal of by-products; therefore, the application of seawater in zeolite synthesis presents promising economic and ecological benefits.
基金National Key Researchand Development Program of China(2016YFB0400802)+2 种基金National Natural Science Foundation of China(61704176,61974149)Key Research and Development Program of Zhejiang Province(2019C01080,2020C01145)Ningbo Innovation 2025 Major Project(2018B10088,2019B10121).
文摘We report on the carrier dynamic and electronic structure investigations on AlGaN-based deep-ultraviolet multiple quantum wells (MQWs)with lateral polarity domains.The localized potential maximum is predicted near the domain boundaries by first-principle calculation,suggesting carrier localization and efficient radiative recombination.More importantly,lateral band diagrams of the MQWs are proposed based on electron affinities and valance band levels calculated from ultraviolet(UV)photoelectron spectroscopy.The proposed lateral band diagram is further demonstrated by surface potential distribution collected by Kelvin probe microscopy and the density-of-state calculation of energy bands.This work illustrates that lateral polarity structures are playing essential roles in the electronic properties of II nitride photonic devices and may provide novel perspective in the realization of high-efficiency UV emitters.
基金supported by the National Key R&D Program of China(Grant No.2016YFB0400101)the National Science Fund for Distinguished Young Scholars(Grant No.61725403)+8 种基金the National Natural Science Foundation of China(Grant Nos.61574142,61322406,61704171,and11705206)the National Natural Science Foundation of China(Grant No.61774065)the Key Program of the International Partnership Program of Chinese Academy of Sciences(Grant No.181722KYSB20160015)the Special Project for Inter-government Collaboration of the State Key Research and Development Program(Grant No.2016YFE0118400)the Science and Technology Service Network Initiative of the Chinese Academy of Sciences,the Jilin Provincial Science&Technology Department(Grant No.20180201026GX)the CAS Interdisciplinary Innovation Team,and the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2015171)the support of King Abdullah University of Science and Technology(KAUST)Baseline(Grant No.BAS/1/1664-01-01)the Competitive Research(Grant No.URF/1/3437-01-01)Gulf Cooperation Council(GCC)Research Council(Grant No.REP/1/3189-01-01)
文摘Surface potentials in the vicinity of V-pits(cone bottom) and U-pits(blunt bottom) on epitaxial GaN surface have been systematically studied using ultraviolet(UV) light-assisted Kelvin probe force microscopy(KPFM). The band structure models are established to understand variation of the surface potentials at the pits and planar surface with and without UV light. The photo-generated carrier behavior at the pit defects is studied. According to the surface potential results, it can be deduced that the carrier distributions around the V-and U-pits are uneven. In dark, the electron concentration at the bottom of V-pit(30 n_0) and Upit(15 n_0) are higher than that at planar surface(n_0). Under UV light, for V-pit, the electron concentration at the cone bottom(4.93×10^(11) n_0) is lower than that at the surrounding planar surface(5.68×10^(13) n_0). For U-pit, the electron concentration at the blunt bottom is 1.35×10^(12) n_0, which is lower than that at the surrounding planar surface(6.13×10^(13) n_0). The non-equilibrium electron concentrations at different locations are calculated. Based on the non-equilibrium electron concentration, it can be concluded that the carrier recombination rate at pit defects is higher than that at planar surface.
基金This research was supported by the National Natural Science Foundation of China (Nos. 81573267, 91413103 and 91213303).
文摘The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer's disease (AD) treatment as an inhibitor of PS1/BACE1 interaction. 3-a-Akebonoic acid, which emanated from a high throughput screening (HTS), was discovered to interfere with P S 1/BACE 1 interaction and reduce amyloid β-protein (Aβ) production. In view of the limited source, we instead used naturally rich betulinic acid (compound 2) as starting material for lead optimization and a focused library of its derivatives was constructed to gain a better understanding of the structure activity relationship (SAR) of triterpenoid-type inhibitor of PS1/BACE1 interaction. Compound 22 was finally chosen as the most potent PS 1/BACE 1 interaction inhibitor, which reduced Aβgeneration effectively.
基金support of KAUST Baseline Fund BAS/1/1664-01-01,KAUST Competitive Research Grants URF/1/3437-01-01,URF/1/3771-01-01KAUST Near-term Grand Challenge Fund REI/1/4999-01-01KAUST Impact Acceleration Fund REI/1/5124-01-01.
文摘The traditional plasma etching process for defining micro-LED pixels could lead to significant sidewall damage.Defects near sidewall regions act as non-radiative recombination centers and paths for current leakage,significantly deteriorating device performance.In this study,we demonstrated a novel selective thermal oxidation(STO)method that allowed pixel definition without undergoing plasma damage and subsequent dielectric passivation.Thermal annealing in ambient air oxidized and reshaped the LED structure,such as p-layers and InGaN/GaN multiple quantum wells.Simultaneously,the pixel areas beneath the pre-deposited SiO_(2)layer were selectively and effectively protected.It was demonstrated that prolonged thermal annealing time enhanced the insulating properties of the oxide,significantly reducing LED leakage current.Furthermore,applying a thicker SiO_(2)protective layer minimized device resistance and boosted device efficiency effectively.Utilizing the STO method,InGaN green micro-LED arrays with 50-,30-,and 10-μm pixel sizes were manufactured and characterized.The results indicated that after 4 h of air annealing and with a 3.5-μm SiO_(2)protective layer,the 10-μm pixel array exhibited leakage currents density 1.2×10^(-6)A/cm^(2)at-10 V voltage and a peak on-wafer external quantum efficiency of~6.48%.This work suggests that the STO method could become an effective approach for future micro-LED manufacturing to mitigate adverse LED efficiency size effects due to the plasma etching and improve device efficiency.Micro-LEDs fabricated through the STO method can be applied to micro-displays,visible light communication,and optical interconnect-based memories.Almost planar pixel geometry will provide more possibilities for the monolithic integration of driving circuits with micro-LEDs.Moreover,the STO method is not limited to micro-LED fabrication and can be extended to design other III-nitride devices,such as photodetectors,laser diodes,high-electron-mobility transistors,and Schottky barrier diodes.
基金King Abdullah University of Science and Technology Baseline Fund(BAS/1/1664-01-01)Competitive Research Grants(URF/1/3437-01-01,URF/1/3771-01-01).
文摘We demonstrate a neural network capable of designing on-demand multiple symmetry-protected bound states in the continuum(BICs)in freeform structures with predefined symmetry.The latent representation of the freeform structures allows the tuning of the geometry in a differentiable,continuous way.We show the rich band inversion and accidental degeneracy in these freeform structures by interacting with the latent representation directly.Moreover,a high design accuracy is demonstrated for arbitrary control of multiple BIC frequencies by using a photonic property readout network to interpret the latent representation.
基金Tianjin Committee of Science and Technology of China(Grant No.22ZYJDSS00040 and 20JCYBJC00060)National Natural Science Foundation of China(Grant No.81872996)。
基金National Natural Science Foundation of China(NSFC)(11504435,11147014)Natural Science Foundation of Hubei Province,China(2013CFA052)+1 种基金King Abdullah University of Science and Technology(KAUST)(Baseline BAS/1/1664-01-01)Fundamental Research Funds for the Central Universities,South-Central University for Nationalities,China(CZY18001)
文摘Connected-annular-rods photonic crystals(CARPCs) in both triangular and square lattices are proposed to enhance the two-dimensional complete photonic bandgap(CPBG) for chalcogenide material systems with moderate refractive index contrast. For the typical chalcogenide-glass–air system with an index contrast of 2.8:1, the optimized square lattice CARPC exhibits a significantly larger normalized CPBG of about 13.50%, though the use of triangular lattice CARPC is unable to enhance the CPBG. It is almost twice as large as our previously reported result [IEEE J. Sel. Top. Quantum Electron. 22, 4900108(2016)]. Moreover, the CPBG of the square-lattice CARPC could remain until an index contrast as low as 2.24:1. The result not only favors wideband CPBG applications for index contrast systems near 2.8:1, but also makes various optical applications that are dependent on CPBG possible for more widely refractive index contrast systems.
基金supported by KAUST BaselineFund:BAS/1/1664-01-01,KAUST Near-term Grand Challenge Fund:REI/1/4999-01-01,KAUST Impact Acceleration Fund:REI/1/5124-01-01.
文摘Wide-bandgap semiconductors exhibit much larger energybandgaps than traditional semiconductors such as silicon,rendering them very promising to be applied in the fields of electronics and optoelectronics.Prominent examples of semiconductors include SiC,GaN,ZnO,and diamond,which exhibitdistinctive characteristics such as elevated mobility and thermalconductivity.These characteristics facilitate the operation of awide range of devices,including energy-efficient bipolar junctiontransistors(BJTs)and metal-oxide-semiconductor field-effecttransistors(MOSFETs),as well as high-frequency high-electronmobility transistors(HEMTs)and optoelectronic components suchas light-emitting diodes(LEDs)and lasers.These semiconductorsare used in building integrated circuits(ICs)to facilitate theoperation of power electronics,computer devices,RF systems,andother optoelectronic advancements.These breakthroughs includevarious applications such as imaging,optical communication,andsensing.Among them,the field of power electronics has witnessedtremendous progress in recent years with the development of widebandgap(WBG)semiconductor devices,which is capable ofswitching large currents and voltages rapidly with low losses.However,it has been proven challenging to integrate these deviceswith silicon complementary metal oxide semiconductor(CMOS)logic circuits required for complex control functions.The monolithic integration of silicon CMOS with WBG devices increases thecomplexity of fabricating monolithically integrated smart integrated circuits(ICs).This review article proposes implementingCMOS logic directly on the WBG platform as a solution.However,achieving the CMOS functionalities with the adoption of WBGmaterials still remains a significant hurdle.This article summarizesthe research progress in the fabrication of integrated circuitsadopting various WBG materials ranging from SiC to diamond,with the goal of building future smart power ICs.
文摘Semiconductor UV photonics research has emerged as one of the most heavily invested areas among semiconductor photonics research due to numerous crucial applications such as sterilization,sensing,curing,and communication.The feature issue disseminates nine timely original research and two review papers from leading research groups and companies,covering most frontiers of the semiconductor UV photonics research,from epitaxy,device physics and design,nanostructures,fabrication,packaging,reliability,and application for light-emitting diodes,laser diodes,and photodetectors.