检索结果-南通市图书馆

Stability Analysis and Performance Evaluation of Additive Mixed-Precision Runge-Kutta Methods

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第1期6卷 705-738页

作者： Ben Burnett Sigal Gottlieb zachary j.Grant Center for Scientific Computing and Data Science Research UMass DartmouthNorth DartmouthMassachusettsUSA CSME Michigan State UniversityEast LansingMichiganUSA

Additive Runge-Kutta methods designed for preserving highly accurate solutions in mixed-precision computation were previously proposed and *** specially designed methods use reduced precision for the implicit computations and full precision for the explicit *** this work,we analyze the stability properties of these methods and their sensitivity to the low-precision rounding errors,and demonstrate their performance in terms of accuracy and *** develop codes in FORTRAN and julia to solve nonlinear systems of ODEs and PDEs using the mixed-precision additive Runge-Kutta(MP-ARK)*** convergence,accuracy,and runtime of these methods are *** show that for a given level of accuracy,suitably chosen MP-ARK methods may provide significant reductions in runtime.

关键词： Mixed precision Runge-Kutta methods Additive methods Accuracy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

胞外囊泡异质性无标记表征技术研究进展

中国科学：化学 2022年第9期52卷 1636-1648页

作者：戴一川于亚军王献立江仔玲储开芹 zachary j.smith 中国科学技术大学精密机械与精密仪器系安徽省教育部精密科学仪器安徽普通高校重点实验室合肥230027 中国科学技术大学苏州高等研究院苏州215127

胞外囊泡(extracellular vesicles,EVs)是细胞在信息传递和环境调控时产生的磷脂双分子层膜包裹的囊泡(尺寸为30~1000 nm).近十五年,其生物及临床相关研究发展迅猛,已被视为是细胞间信息传递、癌宿主调节等动态过程的关键因素之一.尽管... 详细信息

胞外囊泡(extracellular vesicles,EVs)是细胞在信息传递和环境调控时产生的磷脂双分子层膜包裹的囊泡(尺寸为30~1000 nm).近十五年,其生物及临床相关研究发展迅猛,已被视为是细胞间信息传递、癌宿主调节等动态过程的关键因素之一.尽管胞外囊泡具有重要的生物学功能,但其尺寸小、结构脆弱且易聚集,传统生化分析和检测技术难以对其实现精准表征.目前,EVs相关的大多数表征技术采用“批量分析”形式,仅提供大量外泌体的平均结果.为了加深对胞外囊泡异质性的认识,以单个EVs为目标的表征技术将成为新的趋势.本文概述了单颗粒水平胞外囊泡表征的光学和非光学的无标记表征方法,包括拉曼显微、等离激元技术、原子力显微和电子显微技术等.相比于传统整体分析方法,单颗粒水平胞外囊泡表征能够提供更加丰富的信息,在生物医药基础研究领域有着广阔前景.

关键词： EVs 外泌体细胞外囊泡无标记技术光学表征技术

Subnanometer-resolved chemical imaging via multivariate analysis of tip-enhanced Raman maps

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2017年第1期6卷 382-389页

作者： Song jiang Xianbiao Zhang Yao Zhang Chunrui Hu Rui Zhang Yang Zhang Yuan Liao zachary j smith Zhenchao Dong jG Hou Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information&Quantum Physics University of Science and Technology of ChinaHefeiAnhui 230026China Department of Precision Machinery and Precision Instrumentation University of Science and Technology of ChinaHefeiAnhui 230026China

Tip-enhanced Raman spectroscopy(TERS)is a powerful surface analysis technique that can provide subnanometer-resolved images of nanostructures with site-specific chemical ***,due to the limitation of weak Raman signals and the resultant difficulty in achieving TERS imaging with good signal-to-noise ratios(SNRs),the conventional single-peak analysis is unsuitable for distinguishing complex molecular architectures at the subnanometer *** we demonstrate that the combination of subnanometer-resolved TERS imaging and advanced multivariate analysis can provide an unbiased panoramic view of the chemical identity and spatial distribution of different molecules on surfaces,yielding high-quality chemical images despite limited SNRs in individual pixel-level *** methodology allows us to exploit the full power of TERS imaging and unambiguously distinguish between adjacent molecules with a resolution of~0.4 nm,as well as to resolve submolecular features and the differences in molecular adsorption *** results provide a promising methodology that promotes TERS imaging as a routine analytical technique for the analysis of complex nanostructures on surfaces.

关键词： chemical imaging hyperspectral imaging multivariate analysis nanoimaging tip-enhanced Raman spectroscopy

Evaluation of Ruminal Dry Matter Disappearance and pH of Dry Corn, High-Moisture Corn, and Rye under in Vitro Conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2024年第3期15卷 327-332页

作者： Warren Carl Rusche zachary Kidd Foster smith South Dakota State University Brookings South Dakota USA

An in vitro experiment was conducted to evaluate the effects of grain type on in vitro dry matter disappearance (IVDMD) and pH using ruminal fluid and a buffer reagent. Five beef cows were used for ruminal fluid collection and ruminal fluid was pooled prior to use. The cows used for ruminal fluid collection were maintained on a forage-based diet (60:40 forage to concentrate) for 28 d prior to ruminal fluid collection. Three grain types were evaluated: 1) dry corn (89% dry matter;DRC), 2) high-moisture corn (72% dry matter;HMC) and 3) rye (89% dry matter;RYE). Data were analyzed as a completely randomized design. A total of twenty-one replications of each grain type were used for statistical analysis (n = 63 tubes total). IVDMD was greater (P ≤ 0.05) by 97.1% and 46.4% for RYE compared to DRC and HMC, respectively. Additionally, IVDMD was greater (P = 0.05) by 34.6% for HMC compared to DRC. Final pH was decreased (P ≤ 0.05) for RYE by 12.3% and 2.8% for RYE compared to DRC and HMC, respectively. Also, final pH was decreased (P = 0.05) by 9.8% for HMC compared to DRC. These data indicate that corn harvest method (dry vs. high-moisture) influences IVDMD and final pH and that rye has a greater disappearance of dry matter and lower final pH than corn under in vitro conditions.

关键词： Corn Grain Processing Ruminal Fermentation Rye

Sparse-Grid Implementation of Fixed-Point Fast Sweeping WENO Schemes for Eikonal Equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第1期6卷 3-29页

作者： zachary M.Miksis Yong-Tao Zhang Department of Applied and Computational Mathematics and Statistics University of Notre DameNotre DameIN46556USA

Fixed-point fast sweeping methods are a class of explicit iterative methods developed in the literature to efficiently solve steady-state solutions of hyperbolic partial differential equations(PDEs).As other types of fast sweeping schemes,fixed-point fast sweeping methods use the Gauss-Seidel iterations and alternating sweeping strategy to cover characteristics of hyperbolic PDEs in a certain direction simultaneously in each sweeping *** resulting iterative schemes have a fast convergence rate to steady-state ***,an advantage of fixed-point fast sweeping methods over other types of fast sweeping methods is that they are explicit and do not involve the inverse operation of any nonlinear local ***,they are robust and flexible,and have been combined with high-order accurate weighted essentially non-oscillatory(WENO)schemes to solve various hyperbolic PDEs in the *** multidimensional nonlinear problems,high-order fixed-point fast sweeping WENO methods still require quite a large amount of computational *** this technical note,we apply sparse-grid techniques,an effective approximation tool for multidimensional problems,to fixed-point fast sweeping WENO methods for reducing their computational ***,we focus on fixed-point fast sweeping WENO schemes with third-order accuracy(Zhang et al.2006[41]),for solving Eikonal equations,an important class of static Hamilton-jacobi(H-j)*** experiments on solving multidimensional Eikonal equations and a more general static H-j equation are performed to show that the sparse-grid computations of the fixed-point fast sweeping WENO schemes achieve large savings of CPU times on refined meshes,and at the same time maintain comparable accuracy and resolution with those on corresponding regular single grids.

关键词： Fixed-point fast sweeping methods Weighted essentially non-oscillatory(WENO)schemes Sparse grids Static Hamilton-jacobi(H-j)equations Eikonal equations

Anneal-free ultra-low loss silicon nitride integrated photonics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第8期13卷 1565-1577页

作者： Debapam Bose Mark W.Harrington Andrei Isichenko Kaikai Liu jiawei Wang Nitesh Chauhan zachary L.Newman Daniel j.Blumenthal Department of Electrical and Computer Engineering University of California Santa BarbaraSanta BarbaraCA 93106USA Octave Photonics LouisvilleCO 80027USA

Heterogeneous and monolithic integration of the versatile low-loss silicon nitride platform with low-temperature materials such as silicon electronics and photonics,III–V compound semiconductors,lithium niobate,organics,and glasses has been inhibited by the need for high-temperature annealing as well as the need for different process flows for thin and thick *** techniques are needed to maintain the state-of-the-art losses,nonlinear properties,and CMOS-compatible processes while enabling this next generation of 3D silicon nitride *** report a significant advance in silicon nitride integrated photonics,demonstrating the lowest losses to date for an anneal-free process at a maximum temperature 250℃,with the same deuterated silane based fabrication flow,for nitride and oxide,for an order of magnitude range in nitride thickness without requiring stress mitigation or *** report record low anneal-free losses for both nitride core and oxide cladding,enabling 1.77 dBm^(-1) loss and 14.9 million Q for 80 nm nitride core waveguides,more than half an order magnitude lower loss than previously reported sub 300℃ *** 800 nm-thick nitride,we achieve as good as 8.66 dBm^(-1) loss and 4.03 million Q,the highest reported Q for a low temperature processed resonator with equivalent device area,with a median of loss and Q of 13.9 dBm^(-1) and 2.59 million each *** demonstrate laser stabilization with over 4 orders of magnitude frequency noise reduction using a thin nitride reference cavity,and using a thick nitride micro-resonator we demonstrate OPO,over two octave supercontinuum generation,and four-wave mixing and parametric gain with the lowest reported optical parametric oscillation threshold per unit resonator *** results represent a significant step towards a uniform ultra-low loss silicon nitride homogeneous and heterogeneous platform for both thin and thick waveguides capable of linear and nonlinear photonic circuits and

关键词： resonator thick free

The best thing a foreign citizen can do is to stay indoors as much as possible

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

国际人才交流 2020年第2期 65-65页

作者： zachary j smith University of Science and Technology of China

The majority of my foreign friends are staying in China,however,a few have left to their home ***,in my personal opinion,traveling exposes you to more danger than staying at ***,because some infected people may have few symptoms,if you travel home,you may bring the virus with you to your home *** these factors together,I believe it is safer and more considerate to others to stay in place for the time being.

关键词： travel traveling however

Comparisons of oxbow lake fish assemblages in relation to bigheaded carp establishment in the lower White River, Arkansas

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2024年第1期13卷 188-205页

作者： Michael A.Eggleton Cody j.Salzmann joseph E.Kaiser Shannon C.F.smith Department of Aquaculture and Fisheries University of Arkansas at Pine Bluff Arkansas Game and Fish Commission Virginia Institute of Marine Science

Background Since the late 1990s, bigheaded carps(largely silver carp [Hypophthalmichthys molitrix] but also bighead carp [H. nobilis]) have established throughout the lower Mississippi River basin. Using previously studied oxbow lakes in the lower White River basin, Arkansas, we compared current(2017, “post-carp” establishment) fish assemblages to historical(2002, “pre-carp” establishment) fish assemblages. Fish assemblages were comprehensively assessed using multiple gears, including boat electrofishing, mini-fyke nets, and experimental small-mesh gill *** T-tests suggested that fish assemblage indices of richness, diversity, evenness, and dominance were often greater(P 0.05) between the pre-carp and post-carp period with fish assemblages depicted using mini-fyke nets. Nonmetric multidimensional scaling analyses indicated that fish assemblages differed structurally between pre-carp and post-carp periods. Assemblage differences were linked to both small and large abundance changes for more than 20 species. Abundances of gizzard shad(Dorosoma cepedianum), emerald shiner(Notropis atherinoides), pugnose minnow(Opsopoeodus emiliae), crappies(Pomoxis spp.), bluegill(Lepomis macrochirus), orangespotted sunfish(L. humilis), and yellow bass(Morone mississippiensis) declined between the pre-carp and postcarp periods. Conversely, abundances of weed shiner(N. texanus), pallid shiner(Hybopsis amnis), longear sunfish(L. megalotis), buffalofishes(Ictiobus spp.), and gars(Lepisosteus spp.) generally increased during the same *** Although not possible to conclude assemblage shifts were entirely related to bigheaded carps due to the absence of an appropriate reference system where carps did not establish, the wide establishment of these carps is one of the most pervasive changes to have occurred in the lower White

关键词： Bigheaded carp Silver carp Aquatic nuisance species Fish assemblage Oxbow lake Large river

大视野成像血细胞计数对微量体液的快速与智能诊断

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

大视野成像血细胞计数对微量体液的快速与智能诊断