检索结果-南通市图书馆

Molecular Chaperone-Dependent Polymer Translocation through Nanopores: The Effects of Chaperone Concentration and Chaperone-Polymer Interaction

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第1期42卷 125-132,I0011页

作者： Chang-Sheng Zuo Kang Wang Li-Zhen sun Ting-Ting sun Department of Physics Zhejiang University of Science and TechnologyHangzhou 310023China Department of Applied Physics Zhejiang University of TechnologyHangzhou 310014China

The polymer translocation through a nanopore from a donor space(or named cis side) to a receiver space(trans side) in the chaperone-induced crowded environment has attracted increasing attention in recent years due to its significance in biological systems and technological applications. In this work, we mainly focus on the effects of chaperone concentration and chaperone-polymer interaction on the polymer translocation. By assuming the polymer translocation to be a quasi-equilibrium process, the free energy F of the polymer can be estimated by Rosenbluth-Rosenbluth method and then the translocation time τ can be calculated by Fokker-Plank equation based on the obtained free energy landscape. Our calculation results show that the translocation time can be controlled by independently tuning the chaperone concentration and chaperone-polymer interaction at the cis side or the trans side. There exists a critical chaperone-polymer attraction ε~*=-0.2 at which the volume exclusion and interaction effects of the chaperone can balance each other. Additionally, we also find that at large chaperone-polymer attraction, the translocation time is mainly governed by the diffusion coefficient of the polymer.

关键词： Polymer translocation Rosenbluth-Rosenbluth method Fokker-Plank equation Free energy landscapes

Catalyst design and structure control for photocatalytic refineries of cellulosic biomass to fuels and chemicals

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第7期94卷 102-127页

作者： Lulu sun Nengchao Luo State Key Laboratory of Catalysis Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Lignocellulosic biomass is the largest renewable hydrocarbon resource on *** cellulose,one of the major components of lignocellulose,powered by solar energy is a promising way of providing lowcarbon-footprint energy chemicals such as H_(2),HCOOH,CO,and transportation ***-of-the-art biorefineries target the full use of biomass feedstocks as they have a maximum collection radius of 75-100 km,requesting efficient and selective photocatalysts that significantly influence the outcome of photocatalytic ***-performed photocatalysts can harvest a broad solar spectrum and are active in breaking the chemical bonds of cellulose,decreasing the capital investments of ***,photocatalysts should control the selectivity of cellulose conversion,originating target products to level down separation *** separation in photocatalysts and interfacial charge transfer between photocatalysts and cellulose affect the activity and selectivity of cellulose refineries to H2 and carbonaceous *** account for the challenges above,this review summarizes photocatalysts for the refineries of cellulose and downstream platform molecules based on the types of products,with the structure features of different types of photocatalysts discussed in relation to the targets of either improving the activity or product *** addition,this review also sheds light on the methods for designing and regulating photocatalyst structures to facilitate photocatalytic refineries of cellulose and platform molecules,meanwhile summarizing proposed future research challenges and opportunities for designing efficient photocatalysts.

关键词： Photocatalysts Biorefineries Cellulose Fuels Hydrogen

Self-Aligning Multi-Modal Transformer for Oropharyngeal Swab Point Localization

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第4期29卷 1082-1091页

作者： Tianyu Liu Fuchun sun Department of Computer Science and Technology Tsinghua UniversityBeijing 100083China

The oropharyngeal swabbing is a pre-diagnostic procedure used to test various respiratory diseases, including COVID and Influenza A (H1N1). To improve the testing efficiency of testing, a real-time, accurate, and robust sampling point localization algorithm is needed for robots. However, current solutions rely heavily on visual input, which is not reliable enough for large-scale deployment. The transformer has significantly improved the performance of image-related tasks and challenged the dominance of traditional convolutional neural networks (CNNs) in the image field. Inspired by its success, we propose a novel self-aligning multi-modal transformer (SAMMT) to dynamically attend to different parts of unaligned feature maps, preventing information loss caused by perspective disparity and simplifying overall implementation. Unlike preexisting multi-modal transformers, our attention mechanism works in image space instead of embedding space, rendering the need for the sensor registration process obsolete. To facilitate the multi-modal task, we collected and annotate an oropharynx localization/segmentation dataset by trained medical personnel. This dataset is open-sourced and can be used for future multi-modal research. Our experiments show that our model improves the performance of the localization task by 4.2% compared to the pure visual model, and reduces the pixel-wise error rate of the segmentation task by 16.7% compared to the CNN baseline.

关键词： segmentation localization transformer multi-modal perception robotic perception

Blindness-free beam scanning antenna with array of array architecture: principle,design,and experiment

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第3期67卷 209-224页

作者： Jianxu sun Yujian CHENG School of Electronic Science and Engineering University of Electronic Science and Technology of China

This paper presents a 66–76-GHz sparsely-excited phased array antenna with the array of array(Ao A) architecture for eliminating the blindness and suppressing the grating lobe when scanning. For the array antennas printed on the thick dielectric layers with high relative permittivity, scanning blindness appears and seriously impacts the radiation performance. To address this issue, the Ao A topology is developed first. It finds that the scanning blindness appears due to the coupling of the radiating Floquet modes to the non-radiating surface wave(SW) modes. Therefore, the array is divided into two types of domino *** inner-phase distributions are introduced into the domino subarrays to break the one-to-one relationship between the Floquet mode and the SW mode. Then, the blindness inside ±60° scanning volume is eliminated by the aperiodic subarrays. Meanwhile, the aperiodic inner-phase distributions enhance the aperiodicity of the array and contribute to suppressing the grating lobe when scanning. Next, the meta-surface-based dipole with the shorted post is chosen as the unit cell for the proposed aperiodic array. Based on these methods,the array achieves the wide-scanning performance of ±60° in the E-plane and ±30° in the H-plane, without the blindness and the grating lobe. Finally, the 16×16 array is built and simulated with the dimension of32 mm × 32 mm. At the highest operating frequency, the simulated gains are 28.42, 25.17, and 24.01 d Bi when scanning to the broadside, 50° in the E-plane, and 30° in the H-plane, respectively. Compared to the ideal gain, it shows that the simulated radiation efficiency is about 84.13%, 62.08%, and 35.23% when scanning to the broadside, 50° in the E-plane, and 30° in the H-plane, respectively. The worst transmission coefficient, i.e., the worst isolation, is-11.97 d B between the central element and its two adjacent elements in the E-plane. The array prototypes are fabricated, and the experiments are carried out to ver

关键词： 6G communication systems phased array AoA aperiodic subarray wideband wide-scanning surface-wave scanning blindness grating lobe

非对称保温塑料大棚内主动通风式酿热补气系统应用初探

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

农业工程学报 2022年第6期38卷 204-212页

作者：曹晏飞石苗王笛杨士晔李建明孙国涛西北农林科技大学园艺学院农业农村部西北设施园艺工程重点实验室杨凌712100 西北农林科技大学机械与电子工程学院杨凌712100

为提高保温型塑料大棚室内空气温度、CO_(2)浓度,该研究在非对称保温塑料大棚内部设计了一种便于控制通风时间的主动通风式酿热补气系统,该系统主要包括发酵池(长×宽×高:7.0 m×2.0 m×2.0 m)、透气板、过滤装置及喷灌装置。以牛粪和... 详细信息

为提高保温型塑料大棚室内空气温度、CO_(2)浓度,该研究在非对称保温塑料大棚内部设计了一种便于控制通风时间的主动通风式酿热补气系统,该系统主要包括发酵池(长×宽×高:7.0 m×2.0 m×2.0 m)、透气板、过滤装置及喷灌装置。以牛粪和小麦、玉米和番茄秸秆为原料,探究了堆肥发酵过程中的温度特征、棚内增温效果、CO_(2)补充效果及其他有害气体扩散特征。结果表明:1)该系统内堆体温度50℃以上共计30 d;2)与对照塑料大棚相比,试验塑料大棚提高夜间空气温度1~3℃;3)堆肥过程中释放的CO_(2)气体使182 m^(2)测量区域内的平均CO_(2)浓度最高达到1997μmol/mol;4)测量区域内NH_(3)、N_(2)O、CH_(4)的浓度变化范围分别是5.7~18.5、1.0~2.4、115~315μmol/mol。主动通风式酿热补气系统可为保温型塑料大棚提供热量和作物生长所需的CO_(2)。

关键词：环境温度 CO_(2) 堆肥主动通风式酿热补气系统

贵州晴隆丁头山铅锌矿床硒超常富集新发现及其地质意义

在线全文

学校读者我要写书评

暂无评论

矿床地质 2020年第4期39卷 568-578页

作者：周家喜安芸林杨智谋罗开孙国涛云南大学地球科学学院云南昆明650500 自然资源部三江成矿作用及资源勘查利用重点实验室云南昆明650500

位于扬子板块西南缘的川滇黔接壤区,处于全球特提斯成矿域和环太平洋成矿域交汇部位、峨眉山大火成岩省内,成矿背景极其特殊,形成了独具特色的优势紧缺矿产(铅锌)、战略性关键矿产(稀散元素)为代表的大型-超大型矿床及相关的成矿系统。... 详细信息

位于扬子板块西南缘的川滇黔接壤区,处于全球特提斯成矿域和环太平洋成矿域交汇部位、峨眉山大火成岩省内,成矿背景极其特殊,形成了独具特色的优势紧缺矿产(铅锌)、战略性关键矿产(稀散元素)为代表的大型-超大型矿床及相关的成矿系统。黔西北地区是川滇黔富稀散元素铅锌特色成矿系统的重要组成部分之一,近年来找矿不断取得重要突破。位于黔西北成矿区南部的丁头山铅锌矿床,是近期找矿突破的一个代表。通过对丁头山矿床闪锌矿LA-ICPMS原位微量元素分析,发现了该矿床Se显著超常富集现象,所测试的90个测点中w(Se)介于19.7×10^-6~172×10^-6,平均含量81.0×10^-6,显著高于Se的地壳丰度(0.05×10^-6)和整个扬子板块周缘同类型矿床硫化物的w(Se)(通常<50×10^-6),暗示其成矿环境极为特殊,很可能与研究区成矿背景有关。通过相关分析,发现丁头山矿床闪锌矿中Se并非直接替代Zn,而是很可能与Cd、In和Fe一起联合置换Zn,即Fe+Cd+Se+In↔4Zn,是一种新的替代方式。丁头山矿床Se超常富集新发现,对理解稀散元素共生分异与超常富集成矿作用具有重要意义,同时表明丁头山矿区及外围具有良好的Se资源潜力,应加强系统勘查和深入研究工作。

关键词：地球化学闪锌矿 Se 超常富集丁头山矿床黔西北富稀散元素铅锌成矿区

Effect of wire mesh casing treatment on axial compressor performance and stability

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第3期37卷 60-76页

作者： Ming ZHANG Jiaming ZHANG Jiahao HU Xu DONG Dakun sun Xiaofeng sun School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310023China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China

In this paper,a kind of Wire Mesh Casing Treatment(WMCT)is proposed to improve the stable operating range of the *** contrast to the traditional circumferential groove,as for WMCT,a layer of wire mesh is laid on the surface of the circumferential *** studies were conducted on the low-speed axial flow compressor,including the groove width,axial location,and mesh *** optimum axial location for WMCT is related to its groove width.A higher wire mesh count results in a smaller compressor stall margin *** simulations were carried out to study the effect of WMCT on the flow structure of the *** wire mesh in the WMCT has a certain flow resistance,which restricts the flow into and out of the *** to the WMCT,the flow parameter in the tip region of the rotor is less sensitive to changes in the operating conditions of the *** WMCT causes the rotor tip blade loading to shift backward,inhibiting the formation of spill forward of the leakage flow,and thus improving the stability of the *** flow resistance on the groove surface is a new degree-of-freedom for the casing treatment designer.

关键词： Axial compressor Wire mesh casing treatment Tip clearance flow Stall margin Blade loading

在线全文

学校读者我要写书评

暂无评论

温室多层覆盖传热系数与热节省率的工程算法

农业工程学报 2011年第7期27卷 264-269页

作者：赵淑梅马承伟刘晨霞张义张建宇孙国涛中国农业大学农业部设施农业工程重点实验室北京100083

针对温室环境工程设计和保温性评价中多层覆盖传热计算问题,研究了根据单层保温幕保温性数据确定多层覆盖传热系数的方法。运用工程传热学理论,推导了由单层保温幕热节省率计算多层保温幕热节省率的公式,进而可计算多层覆盖传热系数。... 详细信息

针对温室环境工程设计和保温性评价中多层覆盖传热计算问题,研究了根据单层保温幕保温性数据确定多层覆盖传热系数的方法。运用工程传热学理论,推导了由单层保温幕热节省率计算多层保温幕热节省率的公式,进而可计算多层覆盖传热系数。计算式揭示了温室单层保温幕和多层覆盖传热参数间的定量关系,通过引入传热阻比这一新概念,形式更加简明。采用多种数据的综合检验结果表明,所提出计算式准确性较高,同一情况下由单层保温幕热节省率计算得出的3层保温幕热节省率,与直接获得的同一热节省率最大相差仅4.6%。论文提出的计算方法,可避免对多种材料组合的各种多层覆盖进行逐一测试,系统地解决了多层覆盖传热计算中热节省率和传热系数确定的问题。

关键词：温室热传递计算传热系数多层覆盖热节省率

Pretreating and normalizing metabolomics data for statistical analysis

在线全文

学校读者我要写书评

暂无评论

Genes & Diseases 2024年第3期11卷 188-205页

作者： Jun sun Yinglin Xia Division of Gastroenterology and Hepatology Department of MedicineDepartment of Microbiology/ImmunologyUIC Cancer CenterUniversity of Illinois ChicagoJesse Brown VA Medical Center Chicago(537)ChicagoIL 60612USA Division of Gastroenterology and Hepatology Department of MedicineUniversity of Illinois ChicagoChicagoIL 60612USA

Metabolomics as a research field and a set of techniques is to study the entire small molecules in biological *** is emerging as a powerful tool generally for pre-cision ***,integration of microbiome and metabolome has revealed the mechanism and functionality of microbiome in human health and ***,metabo-lomics data are very ***/pretreating and normalizing procedures on metabolomics data are usually required before statistical *** this review article,we comprehensively review various methods that are used to preprocess and pretreat metabolo-mics data,including MS-based data and NMR-based data preprocessing,dealing with zero and/or missing values and detecting outliers,data normalization,data centering and scaling,data *** discuss the advantages and limitations of each *** choice for a suitable preprocessing method is determined by the biological hypothesis,the characteristics of the data set,and the selected statistical data analysis *** then provide the perspective of their applications in the microbiome and metabolome research.

关键词： Data centering and scaling Data normalization Data transformation Missing values MS-Baseddata preprocessing NMRData preprocessing Outliers Preprocessing/pretreatment