检索结果-内蒙古大学图书馆

Microencapsulation of capsaicin by solvent evaporation method and thermal stability study of microcapsules

COLLOID JOURNAL 2013年第1期75卷 26-33页

作者： Wang, Jincheng Dong, Xingyu Chen, Sihao Lou, Jianzhong Shanghai Univ Engn Sci Sch Chem & Chem Engn Shanghai 201620 Peoples R China N Carolina Agr & Tech State Univ Coll Engn Greensboro NC 27411 USA

With polylactic acid (PLA) as shell and capsaicin as core substances, microcapsules were prepared based on solvent evaporation method. The orthogonal test was used to analyze the effects of the process conditions such as polyvinyl alcohol and PLA concentrations, stirring rate, and oil/water ratio on the particle size of the microencapsulated capsaicin (MC) agents. The chemical composition, morphology and size distribution of the microcapsules prepared by the most satisfactory conditions were analyzed by Fourier transform infrared spectroscopy, laser light scattering, and scanning electron microscopy. The MC agents had a mean diameter of 3-5 mu m. The thermal properties of the MC agents were measured by differential scanning calorimetry and thermogravimetric analysis, it was demonstrated that the thermal stability of the MC agents was changed or even improved by the encapsulated PLA over the surface, when compared with similar parameters of the uncovered capsaicin. The in vitro release profile suggested that the microcapsules could be a suitable material for controlled release of capsaicin.

关键词： Agents programmable logic arrays Microcapsules evaporation Particle Size size distribution stability study mean diameter SOLVENT EVAPORATION Capsaicin Microencapsulation

来源：评论

学校读者我要写书评

暂无评论

Cooperative Control of Heterogeneous Connected Vehicles With Directed Acyclic Interactions

引用

IEEE INTELLIGENT TRANSPORTATION SYSTEMS MAGAZINE 2021年第2期13卷 127-141页

作者： Zheng, Yang Bian, Yougang Li, Shengbo Eben Li, Shen Tsinghua Univ Dept Automot Engn Beijing Peoples R China Univ Oxford Dept Engn Sci Oxford England Tsinghua Univ Dept Automot Engn State Key Lab Automot Safety & Energy Beijing 100084 Peoples R China Univ Wisconsin Dept Civil & Environm Engn Madison WI 53706 USA

Cooperation of multiple connected vehicles has the potential to benefit the road traffic greatly. In this paper, we consider analysis and synthesis problems of the cooperative control of a platoon of heterogeneous connected vehicles with directed acyclic interactions (characterized by directed acyclic graphs). In contrast to previous works that view heterogeneity as a type of uncertainty, this paper directly takes heterogeneity into account in the problem formulation, allowing us to develop a deeper understanding of the influence of heterogeneity on the collective behavior of a platoon of connected vehicles. Our major strategies include an application of the celebrated internal model principle and an exploitation of lower-triangular structures for platoons with directed acyclic interactions. The major findings include: 1) we explicitly highlight the tracking ability of heterogeneous platoons, showing that the followers can only track the leader's spacing and velocity;2) we analytically derive a stability region of feedback gains for platoons with directed acyclic interactions;3) and consequently we propose a synthesis method based on the solution to an algebraic Riccati equation that shares the dimension of single vehicle dynamics. Numerical experiments are carried out to validate the effectiveness of our results.

关键词： Connected vehicles Topology Stability analysis Vehicle dynamics Numerical stability Analytical models programmable logic arrays

来源：评论

学校读者我要写书评

暂无评论

Properties of Polylactide Inks for Solvent-Cast Printing of Three-Dimensional Freeform Microstructures

引用

LANGMUIR 2014年第4期30卷 1142-1150页

作者： Guo, Shuang-Zhuang Heuzey, Marie-Claude Therriault, Daniel Ecole Polytech Ctr Appl Res Polymers & Composites CREPEC Dept Mech Engn Lab Multiscale Mech Montreal PQ H3C 3A7 Canada Ecole Polytech Ctr Appl Res Polymers & Composites CREPEC Dept Chem Engn Montreal PQ H3C 3A7 Canada

Solvent-cast printing is a highly versatile microfabrication technique that can be used to construct various geometries such as filaments, towers, scaffolds, and freeform circular spirals by the robotic deposition of a polymer solution ink onto a moving stage. In this work, we have performed a comprehensive characterization of the solvent-cast printing process using polylactide (PLA) solutions by analyzing the flow behavior of the solutions, the solvent evaporation kinetics, and the effect of process-related parameters on the crystallization of the extruded filaments. Rotational rheometry at low to moderate shear rates showed a nearly Newtonian behavior of the PLA solutions, while capillary flow analysis based on process-related data indicated shear thinning at high shear rates. Solvent vaporization tests suggested that the internal diffusion of the solvent through the filaments controlled the solvent removal of the extrudates. Different kinds of three-dimensional (3D) structures including a layer-by-layer tower, nine-layer scaffold, and freeform spiral were fabricated, and a processing map was given to show the proper ranges of process-related parameters (i.e., polymer content, applied pressure, nozzle diameter, and robot velocity) for the different geometries. The results of differential scanning calorimetry revealed that slow solvent evaporation could increase the ability of PLA to complete its crystallization process during the filament drying stage. The method developed here offers a new perspective for manufacturing complex structures from polymer solutions and provides guidelines to optimize the various parameters for 3D geometry fabrication.

关键词： Properties Polylactide Inks Solvent-Cast Printing Filaments Printing solvent removal Plasticizers SOLVENT EVAPORATION flow behavior Solvents RATE OF SHEAR complex structure programmable logic arrays Ink Polymer solutions shear thinning Polylactides scaffolds

来源：评论

学校读者我要写书评

暂无评论

Multiple Phase Noises Physical-Layer Authentication

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 2022年第9期70卷 6196-6211页

作者： Xie, Ning Xiong, Wei Chen, Junjie Zhang, Peichang Huang, Lei Su, Jian Shenzhen Univ Coll Elect & Informat Engn Guangdong Key Lab Intelligent Informat Proc Shenzhen 518060 Peoples R China Shenzhen Univ Coll Elect & Informat Engn Guangdong Engn Res Ctr Posit Sensing & Detect Shenzhen 518060 Peoples R China Nanjing Univ Informat Sci & Technol Sch Comp Sci Nanjing 210044 Jiangsu Peoples R China

This paper concerns the problem of defending against spoofing attacks without a secret key. We address the problem using the Physical-Layer-Authentication (PLA) because of its high security, low overhead, and high compatibility. However, many PLA schemes have the following limitations: quantization errors, local optimums, and performance loss due to the change in the communication environment. In this paper, two phase-noise-based PLA schemes are proposed to address the limitations of the prior schemes. We denote the first scheme as the Multiple Phase Noises PLA (MPP) scheme, which realizes the PLA by using multiple phase noise innovations. Note that since the MPP scheme avoids using any quantization algorithm, it outperforms the prior schemes on the authentication performance. We denote the second scheme as the Enhanced Multiple Phase Noises PLA (EMPP) scheme, which introduces an artificial random phase to the transmitted symbols at the transmitter to further improve the authentication performance. The theoretical analyses of the proposed schemes over fading channels are provided, where the closed-form expressions are derived. Theoretical comparisons between the proposed schemes and prior schemes are provided. The theoretical analyses and simulation results demonstrated the superiority of the proposed schemes. In comparison with the prior schemes, the MPP scheme achieves 13% authentication-performance gain without demodulation-performance loss, while the EMPP scheme achieves 42% authentication-performance gain with merely 16% demodulation-performance loss.

关键词： programmable logic arrays Phase noise Authentication Quantization (signal) Estimation Demodulation Wireless communication Physical layer authentication phase noise quantization algorithm performance analysis fading channels

来源：评论

学校读者我要写书评

暂无评论

Evaluation of AVHRR PAL and GIMMS 10-day composite NDVI time series products using SPOT-4 vegetation data for the African continent

引用

INTERNATIONAL JOURNAL OF REMOTE SENSING 2006年第13期27卷 2719-2733页

作者： Fensholt, Rasmus Nielsen, Thomas Theis Stisen, Simon Univ Copenhagen Inst Geog DK-1350 Copenhagen Denmark

Global 8 km resolution AVHRR (advanced very high resolution radiometer) NDVI (normalized difference vegetation index)10-day composite data sets have been used for numerous local to global scale vegetation time series studies during recent years. AVHRR Pathfinder (PAL) NDVI was available from 1981 until 2001, and the new AVHRR GIMMS NDVI was available from 1981 to the present time. A number of aspects potentially introduce noise in the NDVI data set due to the AVHRR sensor design and data processing. NDVI from SPOT-4 VGT data is considered an improvement over AVHRR, and for this reason it is important to examine how and if the differences in sensor design and processing influence continental scale NDVI composite products. In this study, the quality of these AVHRR NDVI time series are evaluated by the continental scale 1 km resolution SPOT-4 vegetation (VGT) 10-day composite (S10) NDVI data. Three years of AVHRR PAL (1998-2000) and seven years of GIMMS (1998-2004) have been compared to 8 km resampled SPOT-4 VGT (1998-2004) data. The dynamic range of SPOT-4 VGT NDVI tends to be higher than the AVHRR PAL NDVI, whereas there is an exact match between AVHRR GIMMS NDVI and SPOT-4 VGT NDVI. Ortho-regression analysis on annually integrated values of AVHRR PAL/GIMMS and SPOT-4 VGT on a continental scale reveals high correlations amongst the AVHRR and the SPOT data set, with lowest RMSE (root mean square error) on the GIMMS/SPOT-4 VGT compared to the PAL/SPOT-4 VGT. Analyses on decade data likewise show that a linear relation exists between Spot-4 VGT NDVI and the two AVHRR composite products;GIMMS explaining most of the Spot-4 VGT NDVI variance compared to PAL. These results show that the AVHRR GIMMS NDVI is more consistent with Spot-4 VGT NDVI compared to AVHRR PAL versus Spot-4 VGT NDVI ( in terms of RMSE and dynamic range) and can therefore be considered the more accurate long time AVHRR data record. Analyses performed on monthly maximum composites and decade composite dat

关键词： LRIT1 gene SHCBP1 gene programmable logic arrays Dataset normalized difference vegetation index

来源：评论

学校读者我要写书评

暂无评论

A Hydrophobic Antireflective and Antidust Coating With $\text{SiO}_2$ and $\text{TiO}_2$ Nanoparticles Using a New 3-D Printing Method for Photovoltaic Panels

引用

IEEE JOURNAL OF PHOTOVOLTAICS 2022年第4期12卷 1014-1026页

作者： Ekren, Nazmi Sarkin, Ali Samet Saglam, Safak Marmara Univ Elect & Elect Engn Dept TR-34854 Istanbul Turkey Osmaniye Korkut Ata Univ TR-80750 Osmaniye Turkey

The main outdoor factors that reduce the efficiency of the photovoltaic (PV) panel are the reflection and refraction of light, dirt, dust, and organic waste accumulating on the panel surface. In this article, an antireflection, self-cleaning coating was applied on the PV panel cover glass with a new method. With the coating, the surface has been given a hydrophobic feature. As a coating method, a 3-D printer has not been seen in the literature and used as a new method. The electrospinning method has also been tried as an alternative method. Solutions in different combinations were developed using polylactic acid or polymethylmethacrylate polymer, chloroform ($\text{CHCl}_3$) as a solvent, and silicon dioxide ($\text{SiO}_2$) and titanium dioxide ($\text{TiO}_2$) nanoparticles as primary materials in a modified 3-D printer for bioprinting. Five PV panels were obtained by applying different 3-D parameters from three solutions, which have the best results. Coating thicknesses are in the range of 3.12-8.47 mu m. Coated and uncoated PV panels were tested in outdoor conditions for ten-day periods. The power outputs of the PV panels were measured, and their ten-day average efficiency was presented. According to the results, the highest efficiency increase is 8.7%. The highest light transmittance is 88.2% at 550 nm. In addition, hydrophobic properties were observed on all surfaces and the water contact angle was measured as 96.18 degrees.

关键词： Coatings Glass Printers Surface treatment programmable logic arrays Printing Solvents 3-D printing antireflection hydrophobic nanoparticle photovoltaic (PV) self-cleaning

来源：评论

学校读者我要写书评

暂无评论

Biodegradable elastomeric polyurethane membranes as chondrocyte carriers for cartilage repair

引用

TISSUE ENGINEERING 2006年第7期12卷 1945-1953页

作者： Chia, Shi-Lu Gorna, Katarzyna Gogolewski, Sylwester Alini, Mauro AO Res Inst Dept Biochem & Cell Biol CH-7270 Davos Switzerland AO Res Inst Dept Polymer Res CH-7270 Davos Switzerland Singapore Gen Hosp Dept Orthoped Surg Singapore 0316 Singapore

Autologous chondrocyte implantation in combination with an autologous periosteal patch has become a clinically accepted procedure for the treatment of articular cartilage defects. The use of periosteum has, however, several drawbacks. We have been able to fabricate thin elastomeric biodegradable polyurethane (PU) membranes that may possibly have an application as a tissue-engineered substitute for the periosteal patch. Three types of membranes varying in pore size and surface texture were used as substrates for bovine chondrocytes in culture. The membranes, marked as P-I, P-II, and P-R, had average pore sizes of 10 to 20 mu m, 40 to 60 mu m, and less than 5 mu m, respectively. A poly(L/DL-lactide) 80/20% micro-porous membrane (PLA) with an average pore size in the range of 10 to 70 mu m was used as a control. There was no difference in the cell proliferation profile among the 4 membranes. In terms of proteoglycan and collagen production, P-I, P-R, and PLA performed similarly to one another. The rate of matrix production appears to be greater in the PU membranes than in the PLA membrane in the first 10 days, although by day 30, the PLA membrane had caught up. In all comparisons, the performance of P-II lagged behind those of the other materials. In conclusion, this preliminary study supports the potential use of this novel group of PUs as a periosteal flap substitute or perhaps as a chondrocyte carrier for matrix-assisted chondrocyte implantation and related techniques. Further studies will be necessary to better define their role in clinical applications for cartilage repair.

关键词： programmable logic arrays Polyurethanes Chondrocyte CIRCUIT TO PRESSURE CONVERTER membrane BIODEGRADABLE Rubber,Artificial Pore size chondrocyte implantation biodegradability

来源：评论

学校读者我要写书评

暂无评论

Interaction-Based Inductive Bias in Graph Neural Networks: Enhancing Protein-Ligand Binding Affinity Predictions From 3D Structures

引用

IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2024年第12期46卷 8191-8208页

作者： Yang, Ziduo Zhong, Weihe Lv, Qiujie Dong, Tiejun Chen, Guanxing Chen, Calvin Yu-Chian Sun Yat Sen Univ Sch Intelligent Syst Engn Artificial Intelligence Med Res Ctr Shenzhen Campus Shenzhen 518107 Peoples R China Chinese Acad Sci Shanghai Inst Mat Med Zhongshan Inst Drug Discovery Zhongshan 528400 Peoples R China Peking Univ Shenzhen Grad Sch AI Sci AI4S Preferred Program Shenzhen 518055 Peoples R China Peking Univ Shenzhen Grad Sch Sch Elect & Comp Engn Shenzhen 518055 Peoples R China China Med Univ Hosp Dept Med Res Taichung 404 Taiwan Asia Univ Dept Bioinformat & Med Engn Taichung 413 Taiwan

Inductive bias in machine learning (ML) is the set of assumptions describing how a model makes predictions. Different ML-based methods for protein-ligand binding affinity (PLA) prediction have different inductive biases, leading to different levels of generalization capability and interpretability. Intuitively, the inductive bias of an ML-based model for PLA prediction should fit in with biological mechanisms relevant for binding to achieve good predictions with meaningful reasons. To this end, we propose an interaction-based inductive bias to restrict neural networks to functions relevant for binding with two assumptions: 1) A protein-ligand complex can be naturally expressed as a heterogeneous graph with covalent and non-covalent interactions;2) The predicted PLA is the sum of pairwise atom-atom affinities determined by non-covalent interactions. The interaction-based inductive bias is embodied by an explainable heterogeneous interaction graph neural network (EHIGN) for explicitly modeling pairwise atom-atom interactions to predict PLA from 3D structures. Extensive experiments demonstrate that EHIGN achieves better generalization capability than other state-of-the-art ML-based baselines in PLA prediction and structure-based virtual screening. More importantly, comprehensive analyses of distance-affinity, pose-affinity, and substructure-affinity relations suggest that the interaction-based inductive bias can guide the model to learn atomic interactions that are consistent with physical reality. As a case study to demonstrate practical usefulness, our method is tested for predicting the efficacy of Nirmatrelvir against SARS-CoV-2 variants. EHIGN successfully recognizes the changes in the efficacy of Nirmatrelvir for different SARS-CoV-2 variants with meaningful reasons.

关键词： Proteins programmable logic arrays Three-dimensional displays Predictive models Graph neural networks Data models Convolution Protein-ligand binding affinity graph neural networks inductive bias drug-target interaction structure-based virtual screening

来源：评论

学校读者我要写书评

暂无评论

Digital System for Acquisition and Processing of Detected Images

引用

IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2012年第3期59卷 552-560页

作者： Abba, A. Fiorini, C. Geraci, A. Politecn Milan Dept Elect DEI I-20133 Milan Italy

The paper presents the digital electronic system for acquisition and processing of images from the detection stage of a compact and high resolution Anger camera to be used in clinical and research environments. Main features of the system are reconfigurability, linearity, low noise and processing data rate through hardware and firmware architecture solutions that also allow the system to operate in the presence of disturbances and electromagnetic noise, while at the same time minimizing the own radiated emissions.

关键词： Biomedical imaging digital acquisition system (DAQ) digital circuits digital signal processors programmable logic arrays

来源：评论

学校读者我要写书评

暂无评论

Thermal behavior of drawn poly(lactic acid)-nanocomposite fiber probed by near-infrared hyperspectral imaging based on roundtrip temperature scan

引用

ANALYTICAL METHODS 2012年第8期4卷 2259-2265页

作者： Shinzawa, Hideyuki Nishida, Masakazu Tanaka, Toshiyuki Kanematsu, Wataru Adv Ind Sci & Technol Res Inst Instrumentat Frontier Tsukuba Ibaraki Japan Aichi Ctr Ind & Sci Technol Mikawa Text Res Ctr Otsuka Gamagori 4430013 Japan

Effect of organoclay on drawing of poly(lactic acid) (PLA) was studied by near-infrared (NIR) hyperspectral imaging. A set of PLA fibers was prepared by melt-spinning. While the fiber samples were drawn with the same drawn ratio (DR), they show different mechanical properties depending on the clay content. The difference in the polymer structure between the samples was analyzed by a roundtrip temperature scan of NIR imaging spectra. Namely, the samples underwent heating and then cooling in the opposite way during the spectral measurement. The development of the spectral residuals between the heating and cooling indicated the presence of the hysteresis arising from the thermal relaxation of the crystalline lamellae. Consequently, the result revealed fine details of the drawing. The addition of proper amount of clay increases the frequency of the spontaneous nucleation of the crystals. In contrast, the excessive amount of clay restricts the drawing of the polymer due to the interaction of the clay and PLA, which eventually provides insufficient mechanical property to the PLA fiber.

关键词： Fiber programmable logic arrays polymer structure clays scanning Heating hyperspectral imagery Mechanical properties THERMAL RELAXATION poly(lactic acid)

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：