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Prediction of particle size and layer-thickness distributions in a continuous horizontal fluidized-bed coating process

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Particuology 2020年第3期18卷 1-12页

作者： P.Bachmann k.chen A.Buck E.Tsotsas Thermal Process Engineering Otto-von-Guericke UniversityUniversit(a)tsplatz 2Magdeburg D-39106Germany Institute of Particle Technology Friedrich-Alexander University Erlangen-NurembergCauerstr.4Erlangen D-91058Germany

To predict the particle size and layer-thickness distributions(LTDs)in a continuously operated horizontal fluidized-bed granulation process,two alternative models were considered.A one-dimensional two-zone model was proposed,which describes with population-balance equations the particle growth in a spraying zone that is separated from the drying *** residence-time distribution(RTD)was calculated from a literature correlation and was coupled with a population-balance model via a tank-in-series model with reflux.A two-dimensional,one-zone population-balance model,which was based directly on the RTD and the feed particle-size distribution(PSD)was also *** experiments were conducted and analyzed microscopically and with a camera optical device to determine the sample *** over the particle population were derived from the PSDs and were analyzed directly by *** compare the simulated data with the experimentally determined distributions,the PSDs were converted to *** good agreement shows that both methods are suitable to determine the PSD from an RTD of an arbitrary granulation process in a horizontal fluidized *** appears necessary with regards to the LTD spread.

关键词： Fluidized bed Continuous process Coating,Residence-time distribution Particle-size distribution Layer-thickness distribution

Engineering Novel Molecular Beacon Constructs to Study Intracellular RNA Dynamics and Localization

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Genomics, Proteomics & Bioinformatics 2017年第5期15卷 279-286页

作者： Zhao Ma Xiaotian Wu Christopher J.krueger Antony k.chen Department of Biomedical Engineering College of Engineering Peking University Beijing 100871 China Wallace H Coulter Department of Biomedical Engineering Georgia Institute of Technology Atlanta GA 30332 USA

With numerous advancements in novel biochemical techniques, our knowledge of the role of RNAs in the regulation of cellular physiology and pathology has grown significantly over the past several decades. Nevertheless, detailed information regarding RNA processing, trafficking, and localization in living cells has been lacking due to technical limitations in imaging single RNA transcripts in living cells with high spatial and temporal resolution. In this review, we discuss tech- niques that have shown great promise for single RNA imaging, followed by highlights in our recent work in the development of molecular beacons （MBs）, a class of nanoscale oligonucleotide-probes, for detecting individual RNA transcripts in living cells. With further refinement of MB design and development of more sophisticated fluorescence microscopy techniques, we envision that MB-based approaches could promote new discoveries of RNA functions and activities.

关键词： Y-O-methyl RNA Phosphorothioate Molecular beacon RNA dynamics Single-molecule RNAimaging

Reconstructing and forecasting the COVID-19 epidemic in the United States using a 5-parameter logistic growth model

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Global Health Research and Policy 2020年第1期5卷 221-227页

作者： Ding-Geng chen Xinguang chen Jenny k.chen School of Social Work University of North CarolinaTate-Turner Kuralt Building 548-CCB#3550Chapel HillNC 27599USA Department of Statistics University of PretoriaPretoriaSouth Africa Department of Epidemiology University of FloridaGainesvilleUSA Department of Statistics and Data Science Cornell UniversityIthacaUSA

Background:Many studies have modeled and predicted the spread of COVID-19(coronavirus disease 2019)in the *** data that begins with the first reported ***,the shortage of testing services to detect infected persons makes this approach subject to error due to its underdetection of early cases in the *** new approach overcomes this limitation and provides data supporting the public policy decisions intended to combat the spread of COVID-19 ***:We used Centers for Disease Control and Prevention data documenting the daily new and cumulative cases of confirmed COVID-19 in the *** January 22 to April 6,2020,and reconstructed the epidemic using a 5-parameter logistic growth *** fitted our model to data from a 2-week window(i.e.,from March 21 to April 4,approximately one incubation period)during which large-scale testing was being *** parameters obtained from this modeling,we reconstructed and predicted the growth of the epidemic and evaluated the extent and potential effects of ***:The data fit the model *** estimated daily growth rate was 16.8%overall with 95%CI:[15.95,17.76%],suggesting a doubling period of 4 *** on the modeling result,the tipping point at which new cases will begin to decline will be on April 7th,2020,with a peak of 32,860 new cases on that *** the end of the epidemic,at least 792,548(95%CI:[789,162,795,934])will be infected in the *** on our model,a total of 12,029 cases were not detected between January 22(when the first case was detected in the U.S.)and April ***:Our findings demonstrate the utility of a 5-parameter logistic growth model with reliable data that comes from a specified period during which governmental interventions were appropriately *** informing public health decision-making,our model adds a tool for more faithfully capturing the spread of the COVID-19 epidemic.

关键词： COVID-19 Epidemics Disease dynamics Population-based model Logistic growth model Prediction Reconstruction Under-detection Tipping point USA

DETERMINATION AND APPLICATION OF LARSON-MILLER PARAMETER FOR HEAT RESISTANT STEEL 12CrlMoV AND 15CrMo

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 471-476页

作者： R.C.Yang k.chen H.X.Feng H.Wang State key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050China

Based on the analysis and processing on relative empirical formula and data, C-values in Larson-Miller (P) expression, P= T(C + Igt), have determined for pearlitic heat resistant steel 12Cr1MoV and 15CrMo(20.62 and 20.30). The simulation experiments of high temperature aging, heated from 1.5 to 873 hours, have been designed and performed for its verification. And in combination with published information and the present nearly quantitative works, it has further been verified that both the degradations of microstructures and mechanical properties show a good accuracy and practicability using the Larson-Miller parameter with the present determined C-values. Finally, the effects of carbon content on C-value are analyzed by the empirical electron theory of solids and molecules (EET).

关键词： pearlitic heat-resistant steel Larson-Miller parameter aging valence electron structure

VARIATION OF SUBSTRUCTURES OF PEARLITIC HEAT RESISTANT STEEL AFTER HIGH TEMPERATURE AGING

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 477-481页

The observations of dislocations, substructures and other microstructural details were conducted mainly by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) for 12CrlMoV pearlitic heat-resistant steel. It is shown that during the high temperature long-term aging, the disordered and jumbled phase-transformed dislocations caused by normalized cooling are recovered and rearranged into cell substructures, and then the dislocation density is reduced gradually. Finally a low density linear dislocation configuration and a stabler dislocation network are formed and ferritic grains grow considerably.

关键词： pearlitic heat-resistant steel aging recovery dislocation substructure dislocation cell

NEAR-INFRARED,BROAD-BAND SPECTRAL IMAGING OF THE HUMAN BREAST FOR QUANTITATIVE OXIMETRY:APPLICATIONS TO HEALTHY AND CANCEROUS BREASTS

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Journal of Innovative Optical Health Sciences 2010年第4期3卷 267-277页

作者： YANG YU ANGELO SASSAROLI DEBBIE k.chen MARC J.HOMER ROGER A.GRAHAM SERGIO FANTINI Department of Biomedical Engineering Tufts University 4 Colby StreetMedfordMA 02155USA Tufts Medical Center Department of Radiology 800 Washington StreetBostonMA 02111USA Tufts Medical Center Department of Surgery 800 Washington StreetBostonMA 02111USA

We have examined ten human subjects with a previously developed instrument for near-infrared diffuse spectral imaging of the female *** instrument is based on a tandem,planar scan of two collinear optical fibers(one for illumination and one for collection)to image a gently compressed breast in a transmission *** optical data collection features a spatial sampling of 25 points/cm2 over the whole breast,and a spectral sampling of 2 points/nm in the 650-900nm wavelength *** the ten human subjects examined,eight are healthy subjects and two are cancer patients with unilateral invasive ductal carcinoma and ductal carcinoma in situ,*** each subject,we generate second-derivative images that identify a network of highly absorbing structures in the breast that we assign to blood vessels.A previously developed paired-wavelength spectral method assigns oxygenation values to the absorbing structures displayed in the second-derivative *** resulting oxygenation images feature average values over the whole breast that are significantly lower in cancerous breasts(69±14%,n=2)than in healthy breasts(85±7%,n=18)(p<0.01).Furthermore,in the two patients with breast cancer,the average oxygenation values in the cancerous regions are also significantly lower than in the remainder of the breast(invasive ductal carcinoma:49±11%vs 61±16%,p<0.01;ductal carcinoma in situ:58±8%vs 77±11%,p<0.001).

关键词： Diffuse spectral imaging near-infrared spectroscopy optical mammography oximetry hemoglobin saturation

Towards standardizing retinal optical coherence tomography angiography:a review

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Light(Science & Applications) 2022年第4期11卷 520-541页

作者： Danuta M.Sampson Adam M.Dubis Fred k.chen Robert J.Zawadzki David D.Sampson Surrey Biophotonics Centre for VisionSpeech and Signal Processing and School of Biosciences and MedicineThe University of SurreyGuildford GU27XHUK NIHR Biomedical Research Centre at Moorflelds Eye Hospital NHS Trust and UCL Institute of Ophthalmology London EC1V 2PDUK. Centre for Ophthalmology and Visual Science(incorporating Lions Eye Institute) The University of Western AustraliaNedlandsWestern Australia 6009Australia. Department of Ophthalmology Royal Perth HospitalPerthWestern Australia 6000Australia. Ophthalmology Department of SurgeryUniversity of MelbourneMelbourneVictoria 3002Australia. Department of Ophthalmology&Vision Science University of California DavisSacramentoCA 95817USA. Surrey Biophotonics Advanced Technology InstituteSchool of Physics and School of Biosciences and MedicineUniversity of SurreyGuildfordSurrey GU27XHUK

The visualization and assessment of retinal microvasculature are important in the study,diagnosis,monitoring,and guidance of treatment of ocular and systemic *** the introduction of optical coherence tomography angiography(OCTA),it has become possible to visualize the retinal microvasculature volumetrically and without a contrast *** lab-based and commercial clinical instruments,imaging protocols and data analysis methods and metrics,have been applied,often inconsistently,resulting in a confusing picture that represents a major barrier to progress in applying OCTA to reduce the burden of *** data and software sharing,and cross-comparison and pooling of data from different studies are *** inabilities have impeded building the large databases of annotated OCTA images of healthy and diseased retinas that are necessary to study and define characteristics of specific *** paper addresses the steps needed to standardize OCTA imaging of the human retina to address these *** review of the OCTA literature,we identify issues and inconsistencies and propose minimum standards for imaging protocols,data analysis methods,metrics,reporting of findings,and clinical practice and,where this is not possible,we identify areas that require further *** hope that this paper will encourage the unification of imaging protocols in OCTA,promote transparency in the process of data collection,analysis,and reporting,and facilitate increasing the impact of OCTA on retinal healthcare delivery and life science investigations.

关键词： transparency steps inconsistent

Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length

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Eye and Vision 2024年第5期10卷 18-27页

作者： Deepaysh D.C.S.Dutt Seyhan Yazar Jason Charng David A.Mackey Fred k.chen Danuta M.Sampson Centre for Ophthalmology and Visual Science(Incorporating Lions Eye Institute) The University of Western AustraliaPerthWAAustralia Garvan Institute of Medical Research SydneyAustralia Ophthalmology Department of SurgeryUniversity of MelbourneEast MelbourneVICAustralia Centre for Eye Research Australia Royal Victorian Eye and Ear HospitalEast MelbourneVICAustralia Surrey Biophotonics Centre for VisionSpeech and Signal Processing and School of Biosciences and MedicineThe University of SurreyGuildfordUK Institute of Ophthalmology University College LondonLondonUK Lions Eye Institute 2 Verdun StreetNedlandsWA 6009Australia

Background:To generate and validate a method to estimate axial length estimated(AL_(est))from spherical equivalent(SE)and corneal curvature[keratometry(k)],and to determine if this AL_(est)can replace actual axial length(AL_(act))for correcting transverse magnification error in optical coherence tomography angiography(OCTA)images using the Littmann-Bennett ***:Data from 1301 participants of the Raine Study Gen2-20 year follow-up were divided into two datasets to generate(n=650)and validate(n=651)a relationship between AL,SE,and *** developed formula was then applied to a separate dataset of 46 participants with AL,SE,and k measurements and OCTA images to estimate and compare the performance of AL_(est)against AL_(act)in correcting transverse magnification error in OCTA images when measuring the foveal avascular zone area(FAZA).Results:The formula for AL_(est)yielded the equation:AL_(est)=2.102k−0.4125SE+7.268,R^(2)=*** was good agreement between AL_(est)and AL_(act)for both study *** mean difference[standard deviation(SD)]between FAZA corrected with AL_(est)and AL_(act)was 0.002(0.015)mm^(2)with the 95%limits of agreement(LoA)of−0.027 to 0.031 mm^(2).In comparison,mean difference(SD)between FAZA uncorrected and corrected with AL_(act)was−0.005(0.030)mm^(2),with 95%LoA of−0.064 to 0.054 mm^(2).Conclusions:AL_(act)is more accurate than AL_(est)and hence should be used preferentially in magnification error correction in the clinical *** corrected with AL_(est)is comparable to FAZA corrected with AL_(act),while FAZA measurements using images corrected with AL_(est)have a greater accuracy than measurements on uncorrected ***,in the absence of AL_(act),clinicians should use AL_(est)to correct for magnification error as this provides for more accurate measurements of fundus parameters than uncorrected images.

关键词： OCTA keratometry Spherical equivalent Axial length Littmann-Bennett formula

Emerging trend for LED wafer level packaging

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Frontiers of Optoelectronics 2012年第2期5卷 119-126页

作者： S.W.Ricky LEE Rong ZHANG k.chen Jeffery C.C.LO Center for Advanced Microsystems Packaging The Hong Kong University of Science&Technology(HKUST)Hong KongChina HkUST LED-FPD Technology R&D Center at Foshan Guangdong 528200 China

Currently most light emitting diode （LED） components are made with individual chip packaging technology. The main manufacturing processes follow conventional chip-based IC packaging. In the past several years, there has been an uprising trend in the IC industry to migrate from chip-based packaging to wafer level packaging （WLP）. Therefore, there is a need for LEDs to catch up. This paper introduces advanced LED WLP technologies. The contents cover key enabling processes such as preparation of silicon sub-mount wafer, implementation of interconnection, deposition of phosphor, wafer level encapsulation, and their integration. The emphasis is placed on how to achieve high throughput, low cost manufacturing through WLE

关键词： light emitting diode (LED) wafer levelpackaging (WLP)