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Light(Science & Applications) 2024年第10期13卷 2342-2352页

作者： Yunxiang Song Yaowen Hu Xinrui Zhu Kiyoul Yang Marko Lončar John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMAUSA Quantum Science and Engineering Harvard UniversityCambridgeMAUSA

Dissipative Kerr solitons from optical microresonators,commonly referred to as soliton microcombs,have been developed for a broad range of applications,including precision measurement,optical frequency synthesis,and ultrastable microwave and millimeter wave generation,all on a *** important goal for microcombs is self-referencing,which requires octave-spanning bandwidths to detect and stabilize the comb carrier envelope offset ***,detection and locking of the comb spacings are often achieved using frequency division by electro-optic *** thin-film lithium niobate photonic platform,with its low loss,strong second-and third-order nonlinearities,as well as large Pockels effect,is ideally suited for these ***,octave-spanning soliton microcombs are challenging to demonstrate on this platform,largely complicated by strong Raman effects hindering reliable fabrication of soliton ***,we demonstrate entirely connected and octave-spanning soliton microcombs on thin-film lithium *** appropriate control over microresonator free spectral range and dissipation spectrum,we show that soliton-inhibiting Raman effects are suppressed,and soliton devices are fabricated with near-unity *** work offers an unambiguous method for soliton generation on strongly Raman-active ***,it anticipates monolithically integrated,self-referenced frequency standards in conjunction with established technologies,such as periodically poled waveguides and electro-optic modulators,on thin-film lithium niobate.

关键词： millimeter soliton resonator

Antiferromagnetism and p-type conductivity of nonstoichiometric nickel oxide thin films

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InfoMat 2020年第4期2卷 769-774页

作者： Mari Napari Tahmida N.Huq Tuhin Maity Daisy Gomersall Kham M.Niang Armin Barthel Juliet E.Thompson Sami Kinnunen Kai Arstila Timo Sajavaara Robert L.ZHoye Andrew J.Flewitt Judith L.MacManus-Driscoll Department of Materials Science and Metallurgy University of CambridgeCambridgeUK Electrical Engineering Division Department of EngineeringUniversity of CambridgeCambridgeUK Department of Physics University of JyvaskylaJyvaskylaFinland Zepler Institute for Photonics and Nanoelectronics University of SouthamptonSouthamptonUK

Nickel oxide(NiO)is one of the most studied transition metal oxides due to its versatile chemical and electronic properties,enabling it to be used in a wide variety of *** its stoichiometric form,NiO is an antiferromagnetic insulator,with resistivity up to 10^13Ωcm.1 When Ni vacancies are introduced,the nonstoichiometric nickel oxide becomes a semiconductor.

关键词： atomic layer deposition chemical vapor deposition nickel oxide solution deposition thin films

Thermalization and relaxation mediated by phonon management in tin-lead perovskites

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Light(Science & Applications) 2023年第9期12卷 1971-1981页

作者： Linjie Dai Junzhi Ye Neil C.Greenham Cavendish Laboratory University of Cambridge19 J.J.Thomson AvenueCambridge CB30HEUK

Understanding and control of ultrafast non-equilibrium processes in semiconductors is key to making use of the full photon energy before relaxation,leading to new ways to break efficiency limits for solar energy *** this work,we demonstrate the observation and modulation of slow relaxation in uniformly mixed tin-lead perovskites(MASn_(x)Pb_(1-x)I_(3)and CsSn_(x)Pb_(1-x)I_(3)nanocrystals).Transient absorption measurements reveal that slow cooling mediated by a hot phonon bottleneck effect appears at carrier densities above~10^(18)cm^(−3)for tin-lead alloy nanocrystals,and tin addition is found to give rise to suppressed *** the alloy nanoparticles,the combination of a newly introduced high-energy band,screened Fröhlich interaction,suppressed Klemens decay and reduced thermal conductivity(acoustic phonon transport)with increased tin content contributes to the slowed *** inorganic nanocrystals where defect states couple strongly with carriers,sodium doping has been confirmed to benefit in maintaining hot carriers by decoupling them from deep defects,leading to a decreased energy-loss rate during thermalization and an enhanced hot phonon bottleneck *** slow cooling we observe uncovers the intrinsic photophysics of perovskite nanocrystals,with implications for photovoltaic applications where suppressed cooling could lead to hot-carrier solar cells.

关键词： alloy relaxation phonon

High Yield Transfer of Clean Large-Area Epitaxial Oxide Thin Films

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Nano-Micro Letters 2021年第2期13卷 363-376页

作者： Bowen Zhang Chao Yun Judith L.MacManus-Driscoll Department of Materials Science and Metallurgy University of Cambridge27 Charles Babbage RoadCambridge CB30FSUK

In this work,we have developed a new method for manipulating and transferring up to 5 mm×10 mm epitaxial oxide thin *** method involves fixing a PET frame onto a PMMA attachment film,enabling transfer of epitaxial films lifted-off by wet chemical etching of a Sr3Al2O6 sacrificial *** crystallinity,surface morphology,continuity,and purity of the films are all preserved in the transfer *** demonstrate the applicability of our method for three different film compositions and structures of thickness~100 ***,we show that by using epitaxial nanocomposite films,lift-off yield is improved by~50% compared to plain epitaxial films and we ascribe this effect to the higher fracture toughness of the *** work shows important steps towards large-scale perovskite thin-film-based electronic device applications.

关键词： Free-standing oxide thin films High yield transfer Wet etching Crack prevention

Promoting axon regeneration in the central nervous system by increasing PI3-kinase signaling

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Neural Regeneration Research 2022年第6期17卷 1172-1182页

作者： Bart Nieuwenhuis Richard Eva John van Geest Center for Brain Repair Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK

Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous *** in the central nervous system fail to regenerate,meaning that injuries or diseases that cause loss of axonal connectivity have life-changing *** 2008,genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic *** is a phosphatase that opposes the actions of PI3-kinase,a family of enzymes that function to generate the membrane phospholipid PIP_(3) from PIP_(2)(phosphatidylinositol(3,4,5)-trisphosphate from phosphatidylinositol(4,5)-bisphosphate).Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase,and was initially demonstrated to promote axon regeneration by signaling through *** recently,additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative *** review describes neuronal signaling pathways downstream of PI3-kinase and PIP3,and considers them in relation to both developmental and regenerative axon *** briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability,and describe how these are affected by signaling through *** highlight the recent finding of a developmental decline in the generation of PIP_(3) as a key reason for regenerative failure,and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous ***,we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.

关键词： axon cytoskeleton axon regeneration axon transport cell signaling central nervous system growth cone neuroprotection PI3-kinase PI3K PTEN trafficking transcription translation

Breath Biopsy^(®) to Identify Exhaled Volatile Organic Compounds Biomarkers for Liver Cirrhosis Detection

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Journal of Clinical and Translational Hepatology 2023年第3期11卷 638-648页

作者： Giuseppe Ferrandino Giovanna De Palo Antonio Murgia Owen Birch Ahmed Tawfike Rob Smith Irene Debiram-Beecham Olga Gandelman Graham Kibble Anne Marie Lydon Alice Groves Agnieszka Smolinska Max Allsworth Billy Boyle Marc P.van der Schee Michael Allison Rebecca C.Fitzgerald Matthew Hoare Victoria K.Snowdon Owlstone Medical CambridgeUK Department of Oncology University of CambridgeHutchison/MRC Research CentreCambridgeUK Department of Pharmacology and Toxicology School for Nutrition and Translational Research in Metabo-lism(NUTRIM)Maastricht University Medical Centerthe Netherlands Department of Medicine University of CambridgeAddenbrooke’s HospitalCambridgeUK Addenbrookes Hepatology and Liver Transplantation Unit Addenbrookes Hospi-talCambridgeUK MRC Cancer Unit Hutchison/MRC Research CentreUniversity of CambridgeCambridgeUK CRUK cambridge Institute CambridgeUK

Background and Aims:The prevalence of chronic liver dis-ease in adults exceeds 30%in some countries and there is significant interest in developing tests and treatments to help control disease progression and reduce healthcare *** is a rich sampling matrix that offers non-invasive so-lutions suitable for early-stage detection and disease *** previously investigated targeted analysis of a single biomarker,here we investigated a multiparametric approach to breath testing that would provide more robust and reliable results for clinical ***:To identify can-didate biomarkers we compared 46 breath samples from cir-rhosis patients and 42 from *** and analysis used Breath Biopsy OMNI™,maximizing signal and contrast to background to provide high confidence biomarker detec-tion based upon gas chromatography mass spectrometry(GC-MS).Blank samples were also analyzed to provide de-tailed information on background volatile organic compounds(VOCs)***:A set of 29 breath VOCs differed significantly between cirrhosis and controls.A classification model based on these VOCs had an area under the curve(AUC)of 0.95±0.04 in cross-validated test *** seven best performing VOCs were sufficient to maximize classifica-tion performance.A subset of 11 VOCs was correlated with blood metrics of liver function(bilirubin,albumin,prothrom-bin time)and separated patients by cirrhosis severity using principal component ***:A set of seven VOCs consisting of previously reported and novel candidates show promise as a panel for liver disease detection and mon-itoring,showing correlation to disease severity and serum biomarkers at late stage.

关键词： Breath Biopsy Non-invasive Biomarker Cirrhosis Liver function test.

Plasmon-directed polymerization:Regulating polymer growth with light

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Nano Research 2018年第12期11卷 6384-6390页

作者： Yunxia Wang Shuangshuang Wang Shunping Zhang Oren A.Scherman Jeremy J.Baumberg Tao Ding Hongxing Xu Key Laboratory of Artificial Micro-and Nano-structures Of Ministry of Education of China School of Physics and Technologywuhan UniversityWuhan 430072China Nanophotonics Centre Cavendish LaboratoryUniversity of CambridgeCambridgeCB30HEUK Department of Chemistry University of CambridgeLensfield RoadCambridgeCB2I EWUK

Plasmon-induced polymerization can facilitate the site-selectivity and orientation of polymer growth, which enriches the toolbox of polymerization and nanofabrication. Here, we demonstrate plasmon-induced polymerization, accomplished by low-power laser excitation of gold nanoparticles (NPs). We selectively control the growth of polymers around single plasmonic NPs while monitoring the polymerization using dark field spectroscopy and subsequent scanning electron microscopy. This plasmon-induced polymerization, generated by hot electron initiation, not only precisely controls the thickness and composition of the polymer coatings but also regulates the location and orientation of the growth, which are strongly influenced by the laser polarization and near-field distribution around the plasmonic NPs. A saturation increase in the polymer thickness provides a strong support for our mechanism. This facile approach of nanoscale polymerization directed by light not only provides new opportunities in nanosynthesis and nanofabrication for functional devices, but also opens many routes for polymer physics and chemistry at the nanoscale level.

关键词： hot electrons plasmons polarization selective growth

Modelling large deformation and soil–water–structure interaction with material point method:Briefing on MPM2017 conference

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Journal of Hydrodynamics 2017年第3期29卷 393-396页

作者： Alexander Rohe Dongfang Liang Deltares DelftThe Netherlands Department of Engineering University of CambridgeCambridgeUK

The 1st International Conference on the Material Point Method for ＂Modelling Large Deformation and Soil–Water–Structure Interaction＂（MPM2017）was held in Delft,The Netherlands on 10-13 January *** is the first conference organised by the Anura3D MPM Research Community,following a series of international workshops and symposia previously held in The Netherlands,UK,Spain and Italy,as part of the European Commission FP7 Marie-Curie project *** are delighted to present seven contributions in this Special Column of the Journal of Hydrodynamics,and take this opportunity to announce that the 2nd conference,MPM2019,will be held in cambridge,UK in January 2019.

关键词： Material point method soil–water–structure interaction meshfree methods particle methods

Avoiding artefacts in MicroCT imaging of collagen scaffolds:Effect of phosphotungstic acid(PTA)-staining and crosslink density

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Bioactive Materials 2022年第2期7卷 210-219页

作者： Kyung-Ah Kwon Daniel V.Bax Jennifer H.Shepherd Ruth E.Cameron Serena M.Best cambridge Centre for Medical Materials Department of Materials Science and MetallurgyUniversity of CambridgeCambridgeUnited Kingdom School of Engineering University of LeicesterLeicesterUnited Kingdom

X-ray micro-computed tomography(μ-CT)can be used to provide both qualitative and quantitative information on the structure of three-dimensional(3D)bioactive *** performed in a dry state,μ-CT accurately reflects the structure of collagen-based scaffolds,but imaging in a wet state offers challenges with *** we have used phosphotungstic acid(PTA)as a contrast agent to visualise fully hydrated collagen scaffolds in a physiologically relevant environment.A systematic investigation was performed to understand the effects of PTA on the results of μ-CT imaging by varying sample processing variables such as crosslinking density,hydration medium and staining *** samples in 0.3% PTA solution overnight completely stained the samples and the treatment provided a successful route forμ-CT analysis of crosslinked ***,significant structural artefacts were observed for samples which were either non-crosslinked or had low levels of crosslinking,which had a heterogeneous interior architecture with collapsed pores at the scaffold *** work highlights the importance of optimising the choice of processing and staining conditions to ensure accurate visualisation for hydrated 3D collagen scaffolds in an aqueous medium.

关键词： MicroCT crosslinking qualitative

THERMAL IMAGING STUDY OF SCALAR TRANSPORT IN SHALLOW WAKES

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Journal of Hydrodynamics 2012年第1期24卷 17-24页

作者： CHONG K.J.Y UKTHUSYANTHAN N.I. LIANG Dong-fang TANG Hong-wu Department of Engineering University of CambridgeCambridge KW Ltd FetchamSurreyUK College of Water Conservancy and I tydropowcr Engineering Hohai University Nanjing 210098 China

The thermal imaging technique relies on the usage of infrared signal to detect the temperature *** temperature as a flow tracer,thermography is used to investigate the scalar transport in the shallow-water wake generated by an emergent circular *** imaging is demonstrated to be a good quantitative flow visualization technique for studying turbulent mixing phenomena in shallow waters.A key advantage of the thermal imaging method over other scalar measurement techniques,such as the Laser Induced Fluorescence（LIF）and Planar Concentration Analysis（PCA）methods,is that it involves a very simple experimental *** dispersion characteristics captured with this technique are found to be similar to past studies with traditional measurement techniques.

关键词： environmental hydraulics shallow wake turbulent mixing thermal imaging vortex street