Today’s explosion of data urgently requires memory technologies capable of storing large volumes of data in shorter time frames,a feat unattain-able with Flash or DRAM.Intel Optane,commonly referred to as three-dimen...Today’s explosion of data urgently requires memory technologies capable of storing large volumes of data in shorter time frames,a feat unattain-able with Flash or DRAM.Intel Optane,commonly referred to as three-dimensional phase change memory,stands out as one of the most promising candidates.The Optane with cross-point architecture is constructed through layering a storage element and a selector known as the ovonic threshold switch(OTS).The OTS device,which employs chalcogenide film,has thereby gathered increased attention in recent years.In this paper,we begin by providing a brief introduction to the discovery process of the OTS phenomenon.Subsequently,we summarize the key elec-trical parameters of OTS devices and delve into recent explorations of OTS materials,which are categorized as Se-based,Te-based,and S-based material systems.Furthermore,we discuss various models for the OTS switching mechanism,including field-induced nucleation model,as well as several carrier injection models.Additionally,we review the progress and innovations in OTS mechanism research.Finally,we highlight the successful application of OTS devices in three-dimensional high-density memory and offer insights into their promising performance and extensive prospects in emerging applications,such as self-selecting memory and neuromorphic computing.展开更多
Chip-scale programmable optical signal processors are often used to flexibly manipulate the optical signals for satisfying the demands in various applications,such as lidar,radar,and artificial intelligence.Silicon ph...Chip-scale programmable optical signal processors are often used to flexibly manipulate the optical signals for satisfying the demands in various applications,such as lidar,radar,and artificial intelligence.Silicon photonics has unique advantages of ultra-high integration density as well as CMOS compatibility,and thus makes it possible to develop large-scale programmable optical signal processors.The challenge is the high silicon waveguides propagation losses and the high calibration complexity for all tuning elements due to the random phase errors.In this paper,we propose and demonstrate a programmable silicon photonic processor for the first time by introducing low-loss multimode photonic waveguide spirals and low-random-phase-error Mach-Zehnder switches.The present chip-scale programmable silicon photonic processor comprises a 1×4 variable power splitter based on cascaded Mach-Zehnder couplers(MZCs),four Ge/Si photodetectors,four channels of thermally-tunable optical delaylines.Each channel consists of a continuously-tuning phase shifter based on a waveguide spiral with a micro-heater and a digitally-tuning delayline realized with cascaded waveguide-spiral delaylines and MZSs for 5.68 ps time-delay step.Particularly,these waveguide spirals used here are designed to be as wide as 2μm,enabling an ultralow propagation loss of 0.28 dB/cm.Meanwhile,these MZCs and MZSs are designed with 2-μm-wide arm waveguides,and thus the random phase errors in the MZC/MZS arms are negligible,in which case the calibration for these MZSs/MZCs becomes easy and furthermore the power consumption for compensating the phase errors can be reduced greatly.Finally,this programmable silicon photonic processor is demonstrated successfully to verify a number of distinctively different functionalities,including tunable time-delay,microwave photonic beamforming,arbitrary optical signal filtering,and arbitrary waveform generation.展开更多
The performance sensitivity of the solid‐state lithium cells to the synergistic interactions of the charge‐transport and mechanical properties of the electrolyte is well acknowledged in the literature,but the quanti...The performance sensitivity of the solid‐state lithium cells to the synergistic interactions of the charge‐transport and mechanical properties of the electrolyte is well acknowledged in the literature,but the quantitative insights therein are very limited.Here,the charge‐transport and mechanical properties of a polymerized ionic‐liquid‐based solid electrolyte are reported.The transference number and diffusion coefficient of lithium in the concentrated solid electrolyte are measured as a function of concentration and stack pressure.The elastoplastic behavior of the electrolyte is quantified under compression,within a home‐made setup,to substantiate the impact of stack pressure on the stability of the Li/electrolyte interface in the symmetric lithium cells.The results spotlight the interaction between the concentration and thickness of the solid electrolyte and the stack pressure in determining the polarization and stability of the solid‐state lithium batteries during extended cycling.展开更多
This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries.The chargetransfer rate constant ...This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries.The chargetransfer rate constant is evaluated for different facets of lithium,namely(100),(110),(101),and(111)as a function of surface charge density with the aid of density functional theory(DFT)calculations.The results highlight and quantify the sensitivity of the rate of lithium plating and stripping to the surface orientation,surface charge density,and charge-transfer over-potential.An intrinsic kinetics competition among the different surface orientations is identified together with an asymmetry between the lithium plating and stripping and showcased to influence the deposit morphology and surface protrusions and indentations.展开更多
1. Introduction The porous electrodes are the crucial components of the modern electrochemical devices including lithium-ion batteries. The detailed configuration of the lithium-insertion, carbon black, and PVDF binde...1. Introduction The porous electrodes are the crucial components of the modern electrochemical devices including lithium-ion batteries. The detailed configuration of the lithium-insertion, carbon black, and PVDF binder particles in a typical electrode of a lithium-ion cell has a significant impact on its energy and power density. A thinner electrode is desired to decrease the battery volume particularly for portable electronics and mobility applications.展开更多
Axonal regeneration in the central nervous system is an energy-intensive process.In contrast to mammals,adult zebrafish can functionally recover from neuronal injury.This raises the question of how zebrafish can cope ...Axonal regeneration in the central nervous system is an energy-intensive process.In contrast to mammals,adult zebrafish can functionally recover from neuronal injury.This raises the question of how zebrafish can cope with this high energy demand.We previously showed that in adult zebrafish,subjected to an optic nerve crush,an antagonistic axon-dendrite interplay exists wherein the retraction of retinal ganglion cell dendrites is a prerequisite for effective axonal repair.We postulate a‘dendrites for regeneration’paradigm that might be linked to intraneuronal mitochondrial reshuffling,as ganglion cells likely have insufficient resources to maintain dendrites and restore axons simultaneously.Here,we characterized both mitochondrial distribution and mitochondrial dynamics within the different ganglion cell compartments(dendrites,somas,and axons)during the regenerative process.Optic nerve crush resulted in a reduction of mitochondria in the dendrites during dendritic retraction,whereafter enlarged mitochondria appeared in the optic nerve/tract during axonal regrowth.Upon dendritic regrowth in the retina,mitochondrial density inside the retinal dendrites returned to baseline levels.Moreover,a transient increase in mitochondrial fission and biogenesis was observed in retinal ganglion cell somas after optic nerve damage.Taken together,these findings suggest that during optic nerve injury-induced regeneration,mitochondria shift from the dendrites to the axons and back again and that temporary changes in mitochondrial dynamics support axonal and dendritic regrowth after optic nerve crush.展开更多
AIM To clarify the diagnostic performance of endocytoscopy for differentiation between neoplastic and nonneoplastic colorectal diminutive polyps.METHODS Patients who underwent endocytoscopy between October and Decembe...AIM To clarify the diagnostic performance of endocytoscopy for differentiation between neoplastic and nonneoplastic colorectal diminutive polyps.METHODS Patients who underwent endocytoscopy between October and December 2016 at Sano Hospital were prospectively recruited. When diminutive polyps(≤5 mm) were detected, the lesions were evaluated by endocytoscopy after being stained with 0.05% crystal violet and 1% methylene blue. The diminutivepolyps were classified into five categories(EC 1 a, 1 b, 2, 3 a, and 3 b). Endoscopists were asked to take a biopsy from any lesion diagnosed as EC1 b(indicator of hyperplastic polyp) or EC2(indicator of adenoma). We have assessed the diagnostic performance of endocytoscopy for EC2 and EC1 b lesions by comparison with the histopathology of the biopsy specimen. RESULTS A total of 39 patients with 63 diminutive polyps were analyzed. All polyps were evaluated by endocytoscopy. The mean polyp size was 3.3 ± 0.9 mm. Among the 63 diminutive polyps, 60 were flat and 3 were pedunculated. The mean time required for EC observation, including the time for staining with crystal violet and methylene blue, was 3.0 ± 1.9 min. Histopathologic evaluation showed that 13 polyps were hyperplastic and 50 were adenomas. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of EC2 for adenoma compared with EC1 b for hyperplastic polyp were 98.0%, 92.3%, 96.8%, 98.0% and 92.3%, respectively. There were only two cases of disagreement between the endoscopic diagnosis made by endocytoscopy and the corresponding histopathological diagnosis.CONCLUSION Endocytoscopy showed a high diagnostic performance for differentiating between neoplastic and non-neoplastic colorectal diminutive polyps, and therefore has the potential to be used for "real-time histopathology".展开更多
We demonstrate the key module of comparators in GaN ICs,based on resistor-transistor logic(RTL)on E-mode wafers in this work.The fundamental inverters in the comparator consist of a p-GaN gate HEMT and a 2DEG resistor...We demonstrate the key module of comparators in GaN ICs,based on resistor-transistor logic(RTL)on E-mode wafers in this work.The fundamental inverters in the comparator consist of a p-GaN gate HEMT and a 2DEG resistor as the load.The function of the RTL comparators is finally verified by a undervoltage lockout(UVLO)circuit.The compatibility of this circuit with the current p-GaN technology paves the way for integrating logic ICs together with the power devices.展开更多
On-chip integration of electronics and photonics have attracted substantial amount of interest in recent decades. Major obstacles to the realization of this integration are size mismatch between electronic and photoni...On-chip integration of electronics and photonics have attracted substantial amount of interest in recent decades. Major obstacles to the realization of this integration are size mismatch between electronic and photonic circuits, as well as issues with ever-increasing requirements for energy efficiency, bandwidth, optical loss, and drive voltage. Another important issue is the absence of photonic materials that make such integration commercially possible in foundry-compatible processes. Future integration involves combination of various materials and platforms. During the last decade there has been an increasing interest in exploiting various photonic platforms to overcome these obstacles. Integration of silicon photonics[1–3] with technologies such as plasmonics[4–6], photonic crystal architectures[7], and hybrid materials[8] have been widely pursued for photonic integration.展开更多
基金M.Zhu acknowledges support by the National Outstanding Youth Program(62322411)the Hundred Talents Program(Chinese Academy of Sciences)+1 种基金the Shanghai Rising-Star Program(21QA1410800)The financial support was provided by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB44010200).
文摘Today’s explosion of data urgently requires memory technologies capable of storing large volumes of data in shorter time frames,a feat unattain-able with Flash or DRAM.Intel Optane,commonly referred to as three-dimensional phase change memory,stands out as one of the most promising candidates.The Optane with cross-point architecture is constructed through layering a storage element and a selector known as the ovonic threshold switch(OTS).The OTS device,which employs chalcogenide film,has thereby gathered increased attention in recent years.In this paper,we begin by providing a brief introduction to the discovery process of the OTS phenomenon.Subsequently,we summarize the key elec-trical parameters of OTS devices and delve into recent explorations of OTS materials,which are categorized as Se-based,Te-based,and S-based material systems.Furthermore,we discuss various models for the OTS switching mechanism,including field-induced nucleation model,as well as several carrier injection models.Additionally,we review the progress and innovations in OTS mechanism research.Finally,we highlight the successful application of OTS devices in three-dimensional high-density memory and offer insights into their promising performance and extensive prospects in emerging applications,such as self-selecting memory and neuromorphic computing.
基金We are grateful for financial supports from National Major Research and Development Program(No.2018YFB2200200)National Science Fund for Distinguished Young Scholars(61725503)+1 种基金Zhejiang Provincial Natural Science Foundation(LZ18F050001,LGF21F050003)National Natural Science Foundation of China(NSFC)(91950205,6191101294,11861121002,61905209,62175214,62111530147).
文摘Chip-scale programmable optical signal processors are often used to flexibly manipulate the optical signals for satisfying the demands in various applications,such as lidar,radar,and artificial intelligence.Silicon photonics has unique advantages of ultra-high integration density as well as CMOS compatibility,and thus makes it possible to develop large-scale programmable optical signal processors.The challenge is the high silicon waveguides propagation losses and the high calibration complexity for all tuning elements due to the random phase errors.In this paper,we propose and demonstrate a programmable silicon photonic processor for the first time by introducing low-loss multimode photonic waveguide spirals and low-random-phase-error Mach-Zehnder switches.The present chip-scale programmable silicon photonic processor comprises a 1×4 variable power splitter based on cascaded Mach-Zehnder couplers(MZCs),four Ge/Si photodetectors,four channels of thermally-tunable optical delaylines.Each channel consists of a continuously-tuning phase shifter based on a waveguide spiral with a micro-heater and a digitally-tuning delayline realized with cascaded waveguide-spiral delaylines and MZSs for 5.68 ps time-delay step.Particularly,these waveguide spirals used here are designed to be as wide as 2μm,enabling an ultralow propagation loss of 0.28 dB/cm.Meanwhile,these MZCs and MZSs are designed with 2-μm-wide arm waveguides,and thus the random phase errors in the MZC/MZS arms are negligible,in which case the calibration for these MZSs/MZCs becomes easy and furthermore the power consumption for compensating the phase errors can be reduced greatly.Finally,this programmable silicon photonic processor is demonstrated successfully to verify a number of distinctively different functionalities,including tunable time-delay,microwave photonic beamforming,arbitrary optical signal filtering,and arbitrary waveform generation.
基金H2020 LEIT Advanced Materials,Grant/Award Number:875557。
文摘The performance sensitivity of the solid‐state lithium cells to the synergistic interactions of the charge‐transport and mechanical properties of the electrolyte is well acknowledged in the literature,but the quantitative insights therein are very limited.Here,the charge‐transport and mechanical properties of a polymerized ionic‐liquid‐based solid electrolyte are reported.The transference number and diffusion coefficient of lithium in the concentrated solid electrolyte are measured as a function of concentration and stack pressure.The elastoplastic behavior of the electrolyte is quantified under compression,within a home‐made setup,to substantiate the impact of stack pressure on the stability of the Li/electrolyte interface in the symmetric lithium cells.The results spotlight the interaction between the concentration and thickness of the solid electrolyte and the stack pressure in determining the polarization and stability of the solid‐state lithium batteries during extended cycling.
基金supported by the European Union’s Horizon 2020 Research and Innovation Program for the Solidify Project(875557)。
文摘This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries.The chargetransfer rate constant is evaluated for different facets of lithium,namely(100),(110),(101),and(111)as a function of surface charge density with the aid of density functional theory(DFT)calculations.The results highlight and quantify the sensitivity of the rate of lithium plating and stripping to the surface orientation,surface charge density,and charge-transfer over-potential.An intrinsic kinetics competition among the different surface orientations is identified together with an asymmetry between the lithium plating and stripping and showcased to influence the deposit morphology and surface protrusions and indentations.
文摘1. Introduction The porous electrodes are the crucial components of the modern electrochemical devices including lithium-ion batteries. The detailed configuration of the lithium-insertion, carbon black, and PVDF binder particles in a typical electrode of a lithium-ion cell has a significant impact on its energy and power density. A thinner electrode is desired to decrease the battery volume particularly for portable electronics and mobility applications.
基金financially supported by the Katholieke Universiteit Leuven Research Council (C14/18/053)the research foundation Flanders (FWO) (G082221N)+1 种基金a personal L’Oréal/UNESCO (For Women in Science) fellowshipa personal FWO fellowship
文摘Axonal regeneration in the central nervous system is an energy-intensive process.In contrast to mammals,adult zebrafish can functionally recover from neuronal injury.This raises the question of how zebrafish can cope with this high energy demand.We previously showed that in adult zebrafish,subjected to an optic nerve crush,an antagonistic axon-dendrite interplay exists wherein the retraction of retinal ganglion cell dendrites is a prerequisite for effective axonal repair.We postulate a‘dendrites for regeneration’paradigm that might be linked to intraneuronal mitochondrial reshuffling,as ganglion cells likely have insufficient resources to maintain dendrites and restore axons simultaneously.Here,we characterized both mitochondrial distribution and mitochondrial dynamics within the different ganglion cell compartments(dendrites,somas,and axons)during the regenerative process.Optic nerve crush resulted in a reduction of mitochondria in the dendrites during dendritic retraction,whereafter enlarged mitochondria appeared in the optic nerve/tract during axonal regrowth.Upon dendritic regrowth in the retina,mitochondrial density inside the retinal dendrites returned to baseline levels.Moreover,a transient increase in mitochondrial fission and biogenesis was observed in retinal ganglion cell somas after optic nerve damage.Taken together,these findings suggest that during optic nerve injury-induced regeneration,mitochondria shift from the dendrites to the axons and back again and that temporary changes in mitochondrial dynamics support axonal and dendritic regrowth after optic nerve crush.
文摘AIM To clarify the diagnostic performance of endocytoscopy for differentiation between neoplastic and nonneoplastic colorectal diminutive polyps.METHODS Patients who underwent endocytoscopy between October and December 2016 at Sano Hospital were prospectively recruited. When diminutive polyps(≤5 mm) were detected, the lesions were evaluated by endocytoscopy after being stained with 0.05% crystal violet and 1% methylene blue. The diminutivepolyps were classified into five categories(EC 1 a, 1 b, 2, 3 a, and 3 b). Endoscopists were asked to take a biopsy from any lesion diagnosed as EC1 b(indicator of hyperplastic polyp) or EC2(indicator of adenoma). We have assessed the diagnostic performance of endocytoscopy for EC2 and EC1 b lesions by comparison with the histopathology of the biopsy specimen. RESULTS A total of 39 patients with 63 diminutive polyps were analyzed. All polyps were evaluated by endocytoscopy. The mean polyp size was 3.3 ± 0.9 mm. Among the 63 diminutive polyps, 60 were flat and 3 were pedunculated. The mean time required for EC observation, including the time for staining with crystal violet and methylene blue, was 3.0 ± 1.9 min. Histopathologic evaluation showed that 13 polyps were hyperplastic and 50 were adenomas. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of EC2 for adenoma compared with EC1 b for hyperplastic polyp were 98.0%, 92.3%, 96.8%, 98.0% and 92.3%, respectively. There were only two cases of disagreement between the endoscopic diagnosis made by endocytoscopy and the corresponding histopathological diagnosis.CONCLUSION Endocytoscopy showed a high diagnostic performance for differentiating between neoplastic and non-neoplastic colorectal diminutive polyps, and therefore has the potential to be used for "real-time histopathology".
文摘We demonstrate the key module of comparators in GaN ICs,based on resistor-transistor logic(RTL)on E-mode wafers in this work.The fundamental inverters in the comparator consist of a p-GaN gate HEMT and a 2DEG resistor as the load.The function of the RTL comparators is finally verified by a undervoltage lockout(UVLO)circuit.The compatibility of this circuit with the current p-GaN technology paves the way for integrating logic ICs together with the power devices.
文摘On-chip integration of electronics and photonics have attracted substantial amount of interest in recent decades. Major obstacles to the realization of this integration are size mismatch between electronic and photonic circuits, as well as issues with ever-increasing requirements for energy efficiency, bandwidth, optical loss, and drive voltage. Another important issue is the absence of photonic materials that make such integration commercially possible in foundry-compatible processes. Future integration involves combination of various materials and platforms. During the last decade there has been an increasing interest in exploiting various photonic platforms to overcome these obstacles. Integration of silicon photonics[1–3] with technologies such as plasmonics[4–6], photonic crystal architectures[7], and hybrid materials[8] have been widely pursued for photonic integration.
