Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency...Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.展开更多
Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manu...Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manufacturing process for fabricating multi-optical-channel atomic vapor cells and an innovative method for batch processing the inner sidewalls of millimeter glass holes to meet optical channel requirements.Surface characterization and transmittance tests demonstrate that the processed inner sidewalls satisfy the criteria for an optical channel.In addition,the construction of an integrated processing platform enables multilayer non-isothermal anode bonding,the filling of inert gases,and the recovery and recycling of noble gases.Measurements of the absorption spectra and free-induction decay signals of xenon-129(^(129)Xe)and xenon-131(^(131)Xe)under different pump-probe schemes demonstrate the suitability of our vapor cell for use in atomic devices including atomic gyroscopes,dual-beam atomic magnetometers,and other optical/atomic devices.The proposed micromolding technology has broad application prospects in the field of optical-device processing.展开更多
Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials l...Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials like nanoparticles,graphene,and nanowires have enhanced sensor performance to allow for cancer biomarker detection,like circulating tumor cells,nucleic acids,proteins and metabolites,at ultra-low concentrations.However,several challenges need to be addressed before electrochemical biosensors can be clinically implemented.These include improving sensor selectivity in complex biological media,device miniaturization for implantable applications,integration with data analytics,handling biomarker variability,and navigating regulatory approval.This editorial critically examines the prospects of electrochemical biosensors for efficient,low-cost and minimally invasive cancer screening.We discuss recent developments in nanotechnology,microfabrication,electronics integration,multiplexing,and machine learning that can help realize the potential of these sensors.However,significant interdisciplinary efforts among researchers,clinicians,regulators and the healthcare industry are still needed to tackle limitations in selectivity,size constraints,data interpretation,biomarker validation,toxicity and commercial translation.With committed resources and pragmatic strategies,electrochemical biosensors could enable routine early cancer detection and dramatically reduce the global cancer burden.展开更多
This article reports on the development of a simple two-step lithography process for double barrier quantum well(DBQW)InGaAs/AlAs resonant tunneling diode(RTD)on a semi-insulating indium phosphide(InP)substrate using ...This article reports on the development of a simple two-step lithography process for double barrier quantum well(DBQW)InGaAs/AlAs resonant tunneling diode(RTD)on a semi-insulating indium phosphide(InP)substrate using an air-bridge technology.This approach minimizes processing steps,and therefore the processing time as well as the required resources.It is particularly suited for material qualification of new epitaxial layer designs.A DC performance comparison between the proposed process and the conventional process shows approximately the same results.We expect that this novel technique will aid in the recent and continuing rapid advances in RTD technology.展开更多
This review article discusses the development of gallium arsenide(GaAs)-based resonant tunneling diodes(RTD)since the 1970s.To the best of my knowledge,this article is the first review of GaAs RTD technology which cov...This review article discusses the development of gallium arsenide(GaAs)-based resonant tunneling diodes(RTD)since the 1970s.To the best of my knowledge,this article is the first review of GaAs RTD technology which covers different epitaxialstructure design,fabrication techniques,and characterizations for various application areas.It is expected that the details presented here will help the readers to gain a perspective on the previous accomplishments,as well as have an outlook on the current trends and future developments in GaAs RTD research.展开更多
Thanks to detailed field investigations, microstructural and geochemical analysis and relationship with enclosing rocks, microfabrics, magmatic typology and metamorphic evolution of the Kantè sepentinites have be...Thanks to detailed field investigations, microstructural and geochemical analysis and relationship with enclosing rocks, microfabrics, magmatic typology and metamorphic evolution of the Kantè sepentinites have been specified for the first time. The Kantè serpentinites in northern Togo constitute a mega-lens of ultrabasic rocks tectonically intercalated in the sericite chlorite schists of the Atacora structural unit. The brecciated, schitotose or massive rock facies are strongly marked by an S1 schistocity plane superimposed by a flat C shear plane linked to a west vergence thrusting movement. The parageneses that compose the metamagmatites are essentially serpentinous, containing plagioclase, opaque minerals (magnetite, chromite, spinel) and pyroxene porphyroblasts. These microfabrics represent relics of a probable gabbroic protolith. In fact, the geochemical characteristics of the Kantè serpentinites suggest that their magmatic typology is that of komatiites or tholeiitic basalts with oceanic arc affinities. They would have been emplaced in an active margin environment. The retromorphic evolution of the protolith corresponds to the phase of involvement in a major tangential contact during the panafrican tectogenesis.展开更多
Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique t...Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique that is based on powder-bed fusion(PBF)to process metals;however,it is currently focused only on the fabrication of macroscale and mesoscale components.This paper reviews the state of the art of the SLM of metallic materials at the microscale level.In comparison with the direct writing techniques that are commonly used for micro AM,micro SLM is attractive due to a number of factors,including a faster cycle time,process simplicity,and material versatility.A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering(SLS)is conducted.In addition to identifying existing issues with SLM at the microscale,which include powder recoating,laser optics,and powder particle size,this paper details potential future directions.A detailed review of existing recoating methods in powder-bed techniques is conducted,along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain.A number of secondary finishing techniques for AM components are reviewed,with a focus on implementation for microscale features and integration with micro SLM systems.展开更多
Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debri...Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debris, and turbulent liquid flow generally deteriorate laser beam transmission stability, leading to low energy efficiency and poor surface quality. Here, we report that a continuous and directional high-speed microjet will form in the laser ablation zone if laser-induced primary cavitation bubbles asymmetrically collapse sequentially near the air-liquid interface under a critical thin liquid layer. The laser-induced microjet can instantaneously and directionally remove secondary bubbles and ablation debris around the laser ablation region, and thus a very stable material removal process can be obtained. The shadowgraphs of high-speed camera reveal that the average speed of laser-induced continuous microjet can be as high as 1.1 m sin its initial 500 μm displacement. The coupling effect of laser ablation, mechanical impact along with the collapse of cavitation bubbles and flushing of high-speed microjet helps achieve a high material removal rate and significantly improved surface quality. We name this uncovered liquid-assisted laser ablation process as laser-induced microjet-assisted ablation(LIMJAA) based on its unique characteristics. High-quality microgrooves with a large depth-to-width ratio of 5.2 are obtained by LIMJAA with a single-pass laser scanning process in our experiments. LIMJAA is capable of machining various types of difficult-to-process materials with high-quality arrays of micro-channels, square and circle microscale through-holes. The results and disclosed mechanisms in our work provide a deep understanding of the role of laser-induced microjet in improving the processing quality of liquid-assisted laser micromachining.展开更多
The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurati...The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurations are considered as a promising candidate to meet the requirements.In this review,recent progress of the different stamping materials and various stamping technologies are first discussed.The merits of each material,manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized,respectively.Further insights on technical difficulties and scientific challenges are finally demonstrated,including the limited thickness of printed electrodes,poor overlay accuracy and printing resolution.展开更多
Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing ...Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing the dimensions of a material into the nanoscale range usually results in the change of its physiochemical properties such as reactivity,crystallinity, and solubility. This review treats the convergence of last research news at the interface of nanostructured biomaterials and tissue engineering for emerging biomedical technologies such as scaffolding and tissue regeneration. The present review is organized into three main sections. The introduction concerns an overview of the increasing utility of nanostructured materials in the field of tissue engineering. It elucidates how nanotechnology, by working in the submicron length scale, assures the realization of a biocompatible interface that is able to reproduce the physiological cell–matrix interaction. The second, more technical section, concerns the design and fabrication of biocompatible surface characterized by micro- and submicroscale features, using microfabrication, nanolithography, and miscellaneous nanolithographic techniques.In the last part, we review the ongoing tissue engineering application of nanostructured materials and scaffolds in different fields such as neurology, cardiology, orthopedics, and skin tissue regeneration.展开更多
Although femtosecond laser microfabrication is one of the most promising three-dimensional(3D) fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By usi...Although femtosecond laser microfabrication is one of the most promising three-dimensional(3D) fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By using etching as a main assistant technique, the processing can be speeded up and an improved structure surface quality can be provided. However,the assistance of a single technique cannot satisfy the increasing demands of fabrication and integration of highly functional 3D microstructures. Therefore, a multi-technique-based 3D microfabrication method is required. In this paper, we briefly review the recent development on etching-assisted femtosecond laser microfabrication(EAFLM). Various processing approaches have been proposed to further strengthen the flexibilities of the EAFLM. With the use of the multi-technique-based microfabrication method, 3D microstructure arrays can be rapidly defined on planar or curved surfaces with high structure qualities.展开更多
Both biological and engineering approaches have contributed significantly to the recent advance in the field of mechanobiology.Collaborating with biologists,bio-engineers and materials scientists have employed the tec...Both biological and engineering approaches have contributed significantly to the recent advance in the field of mechanobiology.Collaborating with biologists,bio-engineers and materials scientists have employed the techniques stemming from the conventional semiconductor industry to rebuild cellular milieus that mimic critical aspects of in vivo conditions and elicit cell/tissue responses in vitro.Such reductionist approaches have help to unveil important mechanosensing mechanism in both cellular and tissue level,including stem cell differentiation and proliferation,tissue expansion,wound healing,and cancer metastasis.In this mini-review,we discuss various microfabrication methods that have been applied to generate specific properties and functions of designer substrates/devices,which disclose cell-microenvironment interactions and the underlying biological mechanisms.In brief,we emphasize on the studies of cell/tissue mechanical responses to substrate adhesiveness,stiffness,topography,and shear flow.Moreover,we comment on the new concepts of measurement and paradigms for investigations of biological mechanotransductions that are yet to emerge due to on-going interdisciplinary efforts in the fields of mechanobiology and microengineering.展开更多
We describe a novel technique, low surface energy Gas Expansion Molding (GEM), to fabricate microbubble arrays in polydimethylsiloxane (PDMS) which are incorporated into parallel plate flow chambers and tested in ...We describe a novel technique, low surface energy Gas Expansion Molding (GEM), to fabricate microbubble arrays in polydimethylsiloxane (PDMS) which are incorporated into parallel plate flow chambers and tested in cell sorting and microcell cuTture applications. This architecture confers several operational advantages that distinguish this technology approach from currently used methods. Herein we describe the GEM process and the parameters that are used to control microbubble formation and a Vacuum-Assisted Coating (VAC) process developed to selectively and spatially alter the PDMS surface chemistry in the wells and on the microchannel surface. We describe results from microflow image visualization studies conducted to investigate fluid streams above and within microbubble wells and conclude with a discussion of cell culture studies in PDMS.展开更多
Conventional 2D intestinal models cannot precisely recapitulate biomimetic features in vitro and thus are unsuitable for various pharmacokinetic applications,development of disease models,and understanding the host-mi...Conventional 2D intestinal models cannot precisely recapitulate biomimetic features in vitro and thus are unsuitable for various pharmacokinetic applications,development of disease models,and understanding the host-microbiome interactions.Thus,recently,efforts have been directed toward recreating in vitro models with intestine-associated unique 3D crypt-villus(for small intestine)or crypt-lumen(for large intestine)architectures.This review comprehensively delineates the current advancements in this research area in terms of the different microfabrication technologies(photolithography,laser ablation,and 3D bioprinting)employed and the physiological relevance of the obtained models in mimicking the features of native intestinal tissue.A major thrust of the manuscript is also on highlighting the dynamic interplay between intestinal cells(both the stem cells and differentiated ones)and different biophysical,biochemical,and mechanobiological cues along with interaction with other cell types and intestinal microbiome,providing goals for the future developments in this sphere.The article also manifests an outlook toward the application of induced pluripotent stem cells in the context of intestinal tissue models.On a concluding note,challenges and prospects for clinical translation of 3D patterned intestinal tissue models have been discussed.展开更多
Occasionally, in complex inherent characteristics of certain rocks, especially anisotropic rocks it may be difficult to measure the uniaxial compressive strength UCS. However, the use of empirical relationships to eva...Occasionally, in complex inherent characteristics of certain rocks, especially anisotropic rocks it may be difficult to measure the uniaxial compressive strength UCS. However, the use of empirical relationships to evaluate the UCS of rock can be more practical and economical. Consequently, this study carried out to predict UCS from microfabrics properties of banded amphibolite rocks using multiple regression analysis. Based on statistical results, rock microfabric parameters, which adequately represent the UCS of a given rock type have been selected. The results show that grain size, shape factor and quartz content have high significant correlation with UCS at 95% confidence level. From multiple regression model, approximately 84% of the variance of the UCS can be estimated by the linear combination of these three parameters. However, according to model performance criteria: correlation coefficient (R = 0.919), variance account for (VAF = 97%) and root mean square error (RMSE = 4.16) the study clearly indicates that the developed model is reliable to predict the UCS. Finally, this approach can be easily extended to the modeling of rock strength in the absence of adequate geological information or abundant data.展开更多
<span style="white-space:normal;">The study of high dielectric materials has received great attention lately as a key passive component for the application of metal-insulator-metal (MIM) capacitors. In...<span style="white-space:normal;">The study of high dielectric materials has received great attention lately as a key passive component for the application of metal-insulator-metal (MIM) capacitors. In this paper, 50 nm thick Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> thin films have been prepared by atomic layer deposition technique on indium tin oxide (ITO) pre-coated glass substrates and titanium nitride (TiN) coated Si substrates with typical MIM capacitor structure. Photolithography and metal lift-off technique were used for processing of the MIM capacitors. Semiconductor Analyzer with probe station was used to perform capacitance-voltage (C-V) characterization with low-medium frequency range. Current-voltage (I-V) characteristics of MIM capacitors were measured on precision source/measurement system. The performance of Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> films of MIM capacitors on glass was examined in the voltage range from <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>5 to 5 V with a frequency range from 10 kHz to 5 MHz. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/ITO/Glass MIM capacitors demonstrate a capacitance density of 1.6 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;">at 100 kHz, a loss tangent ~0.005 at 100 kHz and a leakage current of 1.79 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>8</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/TiN/Si MIM capacitors demonstrate a capacitance density of 1.5 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 100 kHz, a loss tangent ~0.007 at 100 kHz and a lower leakage current of 2.93 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>10</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. The obtained electrical properties could indicate a promising application of MIM Capacitors.</span>展开更多
Two new two-photon absorption (TPA) molecules, named SK-G1 and NT-G1, are synthesized and the photo- physical characteristics are investigated by using linear absorption spectra, one-photon fluorescence spectra and ...Two new two-photon absorption (TPA) molecules, named SK-G1 and NT-G1, are synthesized and the photo- physical characteristics are investigated by using linear absorption spectra, one-photon fluorescence spectra and two-photon excited fluorescence spectra. Both the compounds exhibit TPA properties, and the TPA values determined by z-scan measurement are 10 GM and 39 GM for SK-G1 and NT-G1, respectively, at wavelength 80Ohm. Time-resolved spectroscopic techniques are employed to further explore the excited state dynamics of NT-G l with larger TPA cross section. The research results show that there is an ultrafast intraband energy transfer process (about 3ps) before the formation of charge transfer state with a relatively long lifetime.展开更多
LIGA technique has been developed since 1993 at BSRF, including the fabrication of LIGA mask, deep X ray lithography, electroplating, the pouring molding and the applications in some fields. The LIGA mask with gold ab...LIGA technique has been developed since 1993 at BSRF, including the fabrication of LIGA mask, deep X ray lithography, electroplating, the pouring molding and the applications in some fields. The LIGA mask with gold absorbing structures of 20μm thickness and 5μm width and Kapton membrane of around 5μm thickness has been successfully fabricated and applied to the deep X ray lithography with the PMMA structure of 1mm thickness or above. The beamline from a wiggler is used for the deep X ray lithography of LIGA station and is open to other institutes researching the deep X ray lithography. The normal process of LIGA technique with the exception of molding has been established with the PMMA structures of 500μm thickness at BSRF. The largest aspect ratio of PMMA structures can reach about 50 with the height of 500μm and the lateral size of 10μm. The nickel and copper structures with the thickness of 0.5mm and 1mm have been made by using the electroplating technique. The SU8 as a resist material of deep etch lithography with UV light is also developed in the fabrication of LIGA mask and some devices at BSRF.Electromagnetic stepping micro motor, heat exchange, accelerator, structures used in the EDM (electro discharge machining) are being developed for the future applications.展开更多
This work aims at optimizing densification parameters as well as resistance to hydration and slag attack of MgO-Dolomite refractory grains, processed from Egyptian dolomitc-magnesite raw material up to firing for 1-4 ...This work aims at optimizing densification parameters as well as resistance to hydration and slag attack of MgO-Dolomite refractory grains, processed from Egyptian dolomitc-magnesite raw material up to firing for 1-4 h at 1400-1600 ℃, in relation to their phase composition and microfabric. Minor amount of natural ilmenite mineral (0-2 wt%), separated from Egyptian black sands was used in doping the dolomitc-magnesite.展开更多
基金supported by the Natural Science Foundation of China (Grant No.12234005)the major research and development program of Jiangsu Province (Grant Nos.BE2021007-2 and BK20222007)。
文摘Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.
基金supported in part by the National Key Research and Development Plan(2022YFB3203400)the National Natural Science Foundation of China(62103324 and U1909221)the Natural Science Foundation of Shaanxi(2022JQ-554).
文摘Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manufacturing process for fabricating multi-optical-channel atomic vapor cells and an innovative method for batch processing the inner sidewalls of millimeter glass holes to meet optical channel requirements.Surface characterization and transmittance tests demonstrate that the processed inner sidewalls satisfy the criteria for an optical channel.In addition,the construction of an integrated processing platform enables multilayer non-isothermal anode bonding,the filling of inert gases,and the recovery and recycling of noble gases.Measurements of the absorption spectra and free-induction decay signals of xenon-129(^(129)Xe)and xenon-131(^(131)Xe)under different pump-probe schemes demonstrate the suitability of our vapor cell for use in atomic devices including atomic gyroscopes,dual-beam atomic magnetometers,and other optical/atomic devices.The proposed micromolding technology has broad application prospects in the field of optical-device processing.
文摘Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials like nanoparticles,graphene,and nanowires have enhanced sensor performance to allow for cancer biomarker detection,like circulating tumor cells,nucleic acids,proteins and metabolites,at ultra-low concentrations.However,several challenges need to be addressed before electrochemical biosensors can be clinically implemented.These include improving sensor selectivity in complex biological media,device miniaturization for implantable applications,integration with data analytics,handling biomarker variability,and navigating regulatory approval.This editorial critically examines the prospects of electrochemical biosensors for efficient,low-cost and minimally invasive cancer screening.We discuss recent developments in nanotechnology,microfabrication,electronics integration,multiplexing,and machine learning that can help realize the potential of these sensors.However,significant interdisciplinary efforts among researchers,clinicians,regulators and the healthcare industry are still needed to tackle limitations in selectivity,size constraints,data interpretation,biomarker validation,toxicity and commercial translation.With committed resources and pragmatic strategies,electrochemical biosensors could enable routine early cancer detection and dramatically reduce the global cancer burden.
基金funded by Horizon 2020 Future and Emerging Technologies ChipAI project under the grant agreement 828841.
文摘This article reports on the development of a simple two-step lithography process for double barrier quantum well(DBQW)InGaAs/AlAs resonant tunneling diode(RTD)on a semi-insulating indium phosphide(InP)substrate using an air-bridge technology.This approach minimizes processing steps,and therefore the processing time as well as the required resources.It is particularly suited for material qualification of new epitaxial layer designs.A DC performance comparison between the proposed process and the conventional process shows approximately the same results.We expect that this novel technique will aid in the recent and continuing rapid advances in RTD technology.
文摘This review article discusses the development of gallium arsenide(GaAs)-based resonant tunneling diodes(RTD)since the 1970s.To the best of my knowledge,this article is the first review of GaAs RTD technology which covers different epitaxialstructure design,fabrication techniques,and characterizations for various application areas.It is expected that the details presented here will help the readers to gain a perspective on the previous accomplishments,as well as have an outlook on the current trends and future developments in GaAs RTD research.
文摘Thanks to detailed field investigations, microstructural and geochemical analysis and relationship with enclosing rocks, microfabrics, magmatic typology and metamorphic evolution of the Kantè sepentinites have been specified for the first time. The Kantè serpentinites in northern Togo constitute a mega-lens of ultrabasic rocks tectonically intercalated in the sericite chlorite schists of the Atacora structural unit. The brecciated, schitotose or massive rock facies are strongly marked by an S1 schistocity plane superimposed by a flat C shear plane linked to a west vergence thrusting movement. The parageneses that compose the metamagmatites are essentially serpentinous, containing plagioclase, opaque minerals (magnetite, chromite, spinel) and pyroxene porphyroblasts. These microfabrics represent relics of a probable gabbroic protolith. In fact, the geochemical characteristics of the Kantè serpentinites suggest that their magmatic typology is that of komatiites or tholeiitic basalts with oceanic arc affinities. They would have been emplaced in an active margin environment. The retromorphic evolution of the protolith corresponds to the phase of involvement in a major tangential contact during the panafrican tectogenesis.
基金financial support from the Science and Engineering Research Council,Agency for Science,Technology and Research(A*STAR),Singapore(142 68 00088)
文摘Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique that is based on powder-bed fusion(PBF)to process metals;however,it is currently focused only on the fabrication of macroscale and mesoscale components.This paper reviews the state of the art of the SLM of metallic materials at the microscale level.In comparison with the direct writing techniques that are commonly used for micro AM,micro SLM is attractive due to a number of factors,including a faster cycle time,process simplicity,and material versatility.A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering(SLS)is conducted.In addition to identifying existing issues with SLM at the microscale,which include powder recoating,laser optics,and powder particle size,this paper details potential future directions.A detailed review of existing recoating methods in powder-bed techniques is conducted,along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain.A number of secondary finishing techniques for AM components are reviewed,with a focus on implementation for microscale features and integration with micro SLM systems.
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
基金financially supported by the Guangdong Provincial University Science and Technology Program(Grant No.2020KTSCX119)the Shenzhen Science and Technology Programs(Grant Nos.20200925155508001,GJHZ20190820151801786,JCYJ20210324115608024 and KQTD20170810110250357)。
文摘Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debris, and turbulent liquid flow generally deteriorate laser beam transmission stability, leading to low energy efficiency and poor surface quality. Here, we report that a continuous and directional high-speed microjet will form in the laser ablation zone if laser-induced primary cavitation bubbles asymmetrically collapse sequentially near the air-liquid interface under a critical thin liquid layer. The laser-induced microjet can instantaneously and directionally remove secondary bubbles and ablation debris around the laser ablation region, and thus a very stable material removal process can be obtained. The shadowgraphs of high-speed camera reveal that the average speed of laser-induced continuous microjet can be as high as 1.1 m sin its initial 500 μm displacement. The coupling effect of laser ablation, mechanical impact along with the collapse of cavitation bubbles and flushing of high-speed microjet helps achieve a high material removal rate and significantly improved surface quality. We name this uncovered liquid-assisted laser ablation process as laser-induced microjet-assisted ablation(LIMJAA) based on its unique characteristics. High-quality microgrooves with a large depth-to-width ratio of 5.2 are obtained by LIMJAA with a single-pass laser scanning process in our experiments. LIMJAA is capable of machining various types of difficult-to-process materials with high-quality arrays of micro-channels, square and circle microscale through-holes. The results and disclosed mechanisms in our work provide a deep understanding of the role of laser-induced microjet in improving the processing quality of liquid-assisted laser micromachining.
基金the support and funding from China Scholarship Council(CSC)support by the Leibniz Program of the German Research Foundation(SCHM 1298/26-1)。
文摘The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurations are considered as a promising candidate to meet the requirements.In this review,recent progress of the different stamping materials and various stamping technologies are first discussed.The merits of each material,manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized,respectively.Further insights on technical difficulties and scientific challenges are finally demonstrated,including the limited thickness of printed electrodes,poor overlay accuracy and printing resolution.
文摘Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing the dimensions of a material into the nanoscale range usually results in the change of its physiochemical properties such as reactivity,crystallinity, and solubility. This review treats the convergence of last research news at the interface of nanostructured biomaterials and tissue engineering for emerging biomedical technologies such as scaffolding and tissue regeneration. The present review is organized into three main sections. The introduction concerns an overview of the increasing utility of nanostructured materials in the field of tissue engineering. It elucidates how nanotechnology, by working in the submicron length scale, assures the realization of a biocompatible interface that is able to reproduce the physiological cell–matrix interaction. The second, more technical section, concerns the design and fabrication of biocompatible surface characterized by micro- and submicroscale features, using microfabrication, nanolithography, and miscellaneous nanolithographic techniques.In the last part, we review the ongoing tissue engineering application of nanostructured materials and scaffolds in different fields such as neurology, cardiology, orthopedics, and skin tissue regeneration.
基金Project supported by the National Natural Science Foundation of China(Grant No.51501070)
文摘Although femtosecond laser microfabrication is one of the most promising three-dimensional(3D) fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By using etching as a main assistant technique, the processing can be speeded up and an improved structure surface quality can be provided. However,the assistance of a single technique cannot satisfy the increasing demands of fabrication and integration of highly functional 3D microstructures. Therefore, a multi-technique-based 3D microfabrication method is required. In this paper, we briefly review the recent development on etching-assisted femtosecond laser microfabrication(EAFLM). Various processing approaches have been proposed to further strengthen the flexibilities of the EAFLM. With the use of the multi-technique-based microfabrication method, 3D microstructure arrays can be rapidly defined on planar or curved surfaces with high structure qualities.
文摘Both biological and engineering approaches have contributed significantly to the recent advance in the field of mechanobiology.Collaborating with biologists,bio-engineers and materials scientists have employed the techniques stemming from the conventional semiconductor industry to rebuild cellular milieus that mimic critical aspects of in vivo conditions and elicit cell/tissue responses in vitro.Such reductionist approaches have help to unveil important mechanosensing mechanism in both cellular and tissue level,including stem cell differentiation and proliferation,tissue expansion,wound healing,and cancer metastasis.In this mini-review,we discuss various microfabrication methods that have been applied to generate specific properties and functions of designer substrates/devices,which disclose cell-microenvironment interactions and the underlying biological mechanisms.In brief,we emphasize on the studies of cell/tissue mechanical responses to substrate adhesiveness,stiffness,topography,and shear flow.Moreover,we comment on the new concepts of measurement and paradigms for investigations of biological mechanotransductions that are yet to emerge due to on-going interdisciplinary efforts in the fields of mechanobiology and microengineering.
基金supported by grants fromthe NIH/NIAID 5K25AI060884 to Lisa A.
文摘We describe a novel technique, low surface energy Gas Expansion Molding (GEM), to fabricate microbubble arrays in polydimethylsiloxane (PDMS) which are incorporated into parallel plate flow chambers and tested in cell sorting and microcell cuTture applications. This architecture confers several operational advantages that distinguish this technology approach from currently used methods. Herein we describe the GEM process and the parameters that are used to control microbubble formation and a Vacuum-Assisted Coating (VAC) process developed to selectively and spatially alter the PDMS surface chemistry in the wells and on the microchannel surface. We describe results from microflow image visualization studies conducted to investigate fluid streams above and within microbubble wells and conclude with a discussion of cell culture studies in PDMS.
文摘Conventional 2D intestinal models cannot precisely recapitulate biomimetic features in vitro and thus are unsuitable for various pharmacokinetic applications,development of disease models,and understanding the host-microbiome interactions.Thus,recently,efforts have been directed toward recreating in vitro models with intestine-associated unique 3D crypt-villus(for small intestine)or crypt-lumen(for large intestine)architectures.This review comprehensively delineates the current advancements in this research area in terms of the different microfabrication technologies(photolithography,laser ablation,and 3D bioprinting)employed and the physiological relevance of the obtained models in mimicking the features of native intestinal tissue.A major thrust of the manuscript is also on highlighting the dynamic interplay between intestinal cells(both the stem cells and differentiated ones)and different biophysical,biochemical,and mechanobiological cues along with interaction with other cell types and intestinal microbiome,providing goals for the future developments in this sphere.The article also manifests an outlook toward the application of induced pluripotent stem cells in the context of intestinal tissue models.On a concluding note,challenges and prospects for clinical translation of 3D patterned intestinal tissue models have been discussed.
文摘Occasionally, in complex inherent characteristics of certain rocks, especially anisotropic rocks it may be difficult to measure the uniaxial compressive strength UCS. However, the use of empirical relationships to evaluate the UCS of rock can be more practical and economical. Consequently, this study carried out to predict UCS from microfabrics properties of banded amphibolite rocks using multiple regression analysis. Based on statistical results, rock microfabric parameters, which adequately represent the UCS of a given rock type have been selected. The results show that grain size, shape factor and quartz content have high significant correlation with UCS at 95% confidence level. From multiple regression model, approximately 84% of the variance of the UCS can be estimated by the linear combination of these three parameters. However, according to model performance criteria: correlation coefficient (R = 0.919), variance account for (VAF = 97%) and root mean square error (RMSE = 4.16) the study clearly indicates that the developed model is reliable to predict the UCS. Finally, this approach can be easily extended to the modeling of rock strength in the absence of adequate geological information or abundant data.
文摘<span style="white-space:normal;">The study of high dielectric materials has received great attention lately as a key passive component for the application of metal-insulator-metal (MIM) capacitors. In this paper, 50 nm thick Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> thin films have been prepared by atomic layer deposition technique on indium tin oxide (ITO) pre-coated glass substrates and titanium nitride (TiN) coated Si substrates with typical MIM capacitor structure. Photolithography and metal lift-off technique were used for processing of the MIM capacitors. Semiconductor Analyzer with probe station was used to perform capacitance-voltage (C-V) characterization with low-medium frequency range. Current-voltage (I-V) characteristics of MIM capacitors were measured on precision source/measurement system. The performance of Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> films of MIM capacitors on glass was examined in the voltage range from <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>5 to 5 V with a frequency range from 10 kHz to 5 MHz. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/ITO/Glass MIM capacitors demonstrate a capacitance density of 1.6 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;">at 100 kHz, a loss tangent ~0.005 at 100 kHz and a leakage current of 1.79 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>8</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/TiN/Si MIM capacitors demonstrate a capacitance density of 1.5 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 100 kHz, a loss tangent ~0.007 at 100 kHz and a lower leakage current of 2.93 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>10</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. The obtained electrical properties could indicate a promising application of MIM Capacitors.</span>
基金Supported the Leading Academic Discipline Programme (T0104), the National Natural Science Foundation of China under Grant Nos 10374020 and 10674031, and the Seventh Graduate Students Innovation Foundation of Fudan University.
文摘Two new two-photon absorption (TPA) molecules, named SK-G1 and NT-G1, are synthesized and the photo- physical characteristics are investigated by using linear absorption spectra, one-photon fluorescence spectra and two-photon excited fluorescence spectra. Both the compounds exhibit TPA properties, and the TPA values determined by z-scan measurement are 10 GM and 39 GM for SK-G1 and NT-G1, respectively, at wavelength 80Ohm. Time-resolved spectroscopic techniques are employed to further explore the excited state dynamics of NT-G l with larger TPA cross section. The research results show that there is an ultrafast intraband energy transfer process (about 3ps) before the formation of charge transfer state with a relatively long lifetime.
文摘LIGA technique has been developed since 1993 at BSRF, including the fabrication of LIGA mask, deep X ray lithography, electroplating, the pouring molding and the applications in some fields. The LIGA mask with gold absorbing structures of 20μm thickness and 5μm width and Kapton membrane of around 5μm thickness has been successfully fabricated and applied to the deep X ray lithography with the PMMA structure of 1mm thickness or above. The beamline from a wiggler is used for the deep X ray lithography of LIGA station and is open to other institutes researching the deep X ray lithography. The normal process of LIGA technique with the exception of molding has been established with the PMMA structures of 500μm thickness at BSRF. The largest aspect ratio of PMMA structures can reach about 50 with the height of 500μm and the lateral size of 10μm. The nickel and copper structures with the thickness of 0.5mm and 1mm have been made by using the electroplating technique. The SU8 as a resist material of deep etch lithography with UV light is also developed in the fabrication of LIGA mask and some devices at BSRF.Electromagnetic stepping micro motor, heat exchange, accelerator, structures used in the EDM (electro discharge machining) are being developed for the future applications.
文摘This work aims at optimizing densification parameters as well as resistance to hydration and slag attack of MgO-Dolomite refractory grains, processed from Egyptian dolomitc-magnesite raw material up to firing for 1-4 h at 1400-1600 ℃, in relation to their phase composition and microfabric. Minor amount of natural ilmenite mineral (0-2 wt%), separated from Egyptian black sands was used in doping the dolomitc-magnesite.