检索结果-南通市图书馆

LADA strategy for the synthesis of unnatural amino acids and direct modifications of peptides

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 Chemistry 2023年第6期66卷 1788-1794页

作者： jun-liang Zhou Yun-Qi Liu zhan-Kui Sun Shanghai Frontiers Science Center for Drug Target Identification and Drug Delivery School of Pharmaceutical SciencesShanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Pharm-X CenterSchool of Pharmaceutical SciencesShanghai Jiao Tong UniversityShanghai 200240China AI Pharma Center Zhangjiang Institute for Advanced StudyShanghai Jiao Tong UniversityShanghai 200240China Shanghai Artificial Intelligence Laboratory Shanghai 200232China

Unnatural amino acids(UAAs)are important building blocks in organic synthesis and drug *** are also frequently integrated into peptides or proteins for biological ***,the direct and simplified synthesis of UAAs remains a great *** the same time,vast known peptide modifications are based on carbon-heteroatom *** are no general methods for peptide modifications via the construction of C–C *** address this challenge,herein we propose the LADA strategy,which is composed of two steps:the selective labeling and activation of cysteine residues,the desulfurization to generate carbon-centered radical and the radical addition to alkenes to build C–C *** one-pot protocol has obvious advantages such as good functional group tolerance,biocompatible reaction conditions,and retained *** strategy was successfully utilized for the synthesis of unnatural amino acids and direct modifications of peptides.

关键词： unnatural amino acids peptide modifications desulfurization cysteine radical addition

Nanocrystal technology for drug formulation and delivery

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2015年第1期9卷 1-14页

作者： Tzu-Lan CHANG Honglei zhan Danni liang jun F. liang Department of Chemistry Chemical Biology and Biomedical Engineering Charles V. Schaefer School of Engineering and Sciences Stevens Institute of Technology Hoboken NJ 07030 USA Stony Brook University School of Medicine Stony Brook NY 11794 USA

With the development of modem technology like high throughput screening, combinatorial chemistry and computer aid drug design, the drug discovery process has been dramatically accelerated. However, new drug candidates often exhibit poor aqueous or even organic medium solubility. Additionally, many of them may have low dissolution velocity and low oral bioavailability. Nanocrystal formulation sheds new light on advanced drug development. Due to small （nano- or micro- meters） sizes, the increased surface-volume ratio leads to drama- tically enhanced drug dissolution velocity and saturation solubility. The simplicity in preparation and the potential for various administration routes allow drug nanocrystals to be a novel drug delivery system for specific diseases （i.e. cancer）. In addition to the comprehensive review of different technologies and methods in drug nanocrystal preparation, suspension, and stabilization, we will also compare nano- and micro-sized drug crystals in pharma- ceutical applications and discuss current nanocrystal drugs on the market and their limitations.

关键词： drug nanocrystal nanotechnology formula-tion bioavailability stabilizers drug delivery

Compression strength prediction of Xylosma racemosum using a transfer learning system based on near-infrared spectral data

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2020年第3期31卷 1061-1069页

作者： Guangyu Shi jun cao Chao Li Yuliang liang Northeast Forestry University Harbin 150040People’s Republic of China

A transfer learning system was designed to predict Xylosma racemosum compression ***-infrared(NIR)spectral data for Acer mono and its compression strength values were used to resolve the weak generalization problem caused by using a *** dataset *** component analysis and principal component analysis are domain adaption and feature extraction processes to enable the use of *** NIR spectral data to design the transfer learning system.A five-layer neural network relevant to the *** dataset,was fine-tuned using the *** *** were 109 *** samples used as the source dataset and 79 *** samples as the target *** the ratio of the training set to the test set was 1:9,the correlation coeffi cient was 0.88,and mean square error was *** results show that NIR spectral data of hardwood species are *** the mechanical strength of hardwood species using multi-species NIR spectral datasets will improve the generalization ability of the model and increase accuracy.

关键词： Xylosma racemosum Compression strength prediction Near-infrared spectroscopy Transfer learning system TCA–PCA

Mechanical properties of wood materials using near-infrared spectroscopy based on correlation local embedding and partial least-squares

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2020年第3期31卷 1053-1060页

作者： Lei Yu Yuliang liang Yizhuo zhang jun cao Mechanical and Electrical College Northeast Forestry UniversityHarbin 150040People’s Republic of China

This study used near-infrared(NIR)spectroscopy to predict mechanical properties of *** spectra were collected in wavelengths 900–1700 nm,and spectra averaged by radial and tangential surface spectra were used to establish a partial least square(PLS)model based on correlation local embedding(CLE).Mongolian oak(Quercus mongolica *** Ledeb.)was used to test the eff ectiveness of the *** cross-validation method was used to verify the robustness of the CLE–PLS *** samples were tested as the calibration set and forty-fi ve as the validation *** results show that the prediction coeffi cient of determination(R2 p)is 0.80 for MOR,and 0.78 for *** ratio of performance to deviation is 2.23 for MOR and 2.15 for MOE.

关键词： Modulus of rupture Modulus of elasticity Near-infrared Correlation local embedding Partial least square

Anchorage performance of large-diameter FRP bolts and their application in large deformation roadway

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2023年第8期33卷 1037-1043页

作者： jun Han Zuoqing Bi Bing liang Chen cao Shuangwen Ma College of Mining Liaoning Technical UniversityFuxin 123000China ME EISUniversity of WollongongWollongongNSW 2526Australia

In underground coal mines, fibre reinforced polymer(FRP) bolt is ideal for mined rib reinforcements as it can prevent gas explosions caused by shearer frictional spark. With increasing mining depth, small diameter FRP bolts used in shallow underground mining cannot fulfil the rib support requirements. Under the engineering background of deep underground shortwall mining in Wudong coal mine, this paper systematically studies Φ27 mm FRP bolt support for large deformation coal rib. Specimens with a fan-shaped cross-section were used to enable the tensile testing of the bolt rod, the measured average tensile strength of the studied FRP bolt was(486.1 ± 9.6) MPa with a maximum elongation of 5.7%±0.6%.The shear strength of the bolt was measured as approximately 258 MPa using a self-made double shear testing apparatus. Based on the equivalent radial stiffness principle, a laboratory short encapsulation pullout test(SEPT) method for rib bolting has been developed undertaken consideration of the mechanical properties of the coal seam. Results showed that the average peak anchorage forces of the Φ27 mm FRP bolt and Φ20 mm steel rebar bolt were 108.4 and 66.4 k N, respectively, which were agreed with the theoretical calculations and field measurements. Based on theoretical analysis of the loading states of the bolt under site conditions, bolting method of full-length resin grouting was adopted to offset the weaknesses of the FRP bolt. Numerical method was employed to compare the bolting effect using Φ27 mm FRP bolts and steel rebar bolts. Large diameter FRP bolting was determined as the optimum rib support scheme to increase the productivity of the coal mine and to enhance the ground control capability for+425 level mining roadways. This study provides the laboratory testing design and theoretical prediction of large diameter FRP bolts used for rib support in large deformation roadways.

关键词： FRP bolt Laboratory SEPT Tensile strength Double shear testing Mined rib support Large deformation roadway

Intercritical Rolling Induced Ultrafine Lamellar Structure and Enhanced Mechanical Properties of Medium-Mn Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第5期21卷 551-558页

作者： Wei zhan Li-qiang cao jun HU Wen-quan cao Jian LI Han DONG College of Materials Science and Engineering Huazhong University of Science and Technology Institute for Structural Materials Central Iron and Steel Research Institute(CISRI)

The medium-Mn steel with ferrite and austenite structure was rolled in the intercritical region down to dif- ferent rolling reduction. The microstructure and mechanical properties of the rolled steels were investigated by scan- ning electron microscopy, transmission electron microscopy, X-ray diffraction and tensile tests. It was found that the ferrite and austenite structure gradually evolved into an ultrafine structure from the random directional lath structure to lamellar structure with lath longitudinal direction parallel to the rolling direction with increasing rolling strain. It was found that the thickness of the laths was gradually refined with increasing rolling strain. The lath thickness is about 0. 15 9m stored with high density dislocations and the austenite volume fraction of the steel is about 24% after 80% rolling reduction. Furthermore, it was interesting to find that yield strength, tensile strength and total elongation of the 80% rolled medium-Mn steel are about 1000 MPa, 1250 MPa and 24%, respectively, demonstrating an excellent combination of the strength and ductility. Based on the microstructure examination, it was proposed that the grain refinement of the medium-Mn steels could be attributed to the duplex structure and the low rolling temperature. Analysis of the relationship between the microstructure and the mechanical properties indicated that the high yield strength mainly resulted from the ultrafine grain size and the high density dislocation, but the improved ductili- ty may be attributed to the large fractions of austenite retained after intercritical rolling.

关键词： intercriticaI roiling medium manganese steel rolling reduction ultrafine lameUar structure

Influence of heating rate on reactivity and surface chemistry of chars derived from pyrolysis of two Chinese low rank coals

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2018年第4期28卷 610-616页

作者： liang Dingcheng Xie Qiang Li Guangsheng cao junya zhang jun School of Chemical and Environmental Engineering China University of Mining and Technology (Beijing)

A series of char samples were derived from pyrolysis of two typical low-rank coals in China （Shengli lig- nite and Shenmu bituminous coal） at low, medium and fast heating rates, respectively, to the same pyrol- ysis temperature 750℃. Then these chars were characterized by means of thermogravimetric analysis and Fourier transform infrared spectrometer with the aim to investigate the influence of heating rate in pyrolysis process on gasification reactivity and surface chemistry of them. Besides, a homogeneous model was used to quantitatively analyze the activation energy of gasification reaction. The results reveal that Shengli lignite and its derived chars behave higher gasification reactivity and have less content of oxygen functional groups than Shenmu coal and chars. Meanwhile, chars derived from Shengli lignite at 50℃/min and Shenmu coal at 200℃/min have the greatest gasification reactivity, respectively. The oxygen functional groups in Shengli lignite are easily thermo-decomposed, and they are less affected by the heating rate, while that in Shenmu coal have a significant change with the variation of heating rate. In addition, there is no good correlation between the change of oxygen functional groups and that of the gasification reactivity of the derived chars from pyrolysis at different heating rates.

关键词： Pyrolysis Low rank coal Heating rateReactivity Kinetic parameter Surface chemistry

Hierarchical three-dimensional flower-like Co3O4 archi- tectures with a mesocrystal structure as high capacity anode materials for long-lived lithium-ion batteries

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第3期11卷 1437-1446页

作者： Wenqiang cao Wenzhong Wang Honglong Shi jun Wang Maosheng cao Yujie liang Min Zhu School of Science Minzu University of China Beijing 100081 China Faculty of Sciences Ningbo University Ningbo 315211 China School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China

In this work, we rationally design a high-capacity electrode based on three- dimensional （3D） hierarchical Co3O4 flower-like architectures with a mesocrystal nanostructure. The specific combination of the micro-sized 3D hierarchical architecture and the mesocrystal structure with a high porosity and single crystal-like nature can address the capacity fading and cycling stability as presented in many conversion electrodes for lithium-ion batteries. The hierarchical 3D flower-like Co3O4 architecture accommodates the volume change and mitigates mechanical stress during the lithiation-delithiation processes, and the mesocrystal structure provides extra lithium-ion storage and electron/ion transport paths. The achieved hierarchical 3D Co3O4 flower-like architectures with a mesocrystal nanostructure exhibit a high reversible capacity of 920 mA.h.g-1 after 800 cycles at 1.12 C （1 C = 890 ***）, improved rate performance, and cycling stability. The finding in this work offers a new perspective for designing advanced and long-lived lithium-ion batteries.

关键词： Co3O4 three-dimensional anode materials lithium-ion batteries

低温水浴制备BiVO_(4)光催化材料用于可见光降解RhB研究

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

陕西科技大学学报 2025年第1期43卷 115-125页

作者：余泽翰曹丽云冯亮亮黄剑锋赵勇刘一军董军乐陕西科技大学材料科学与工程学院陕西省国际科技合作基地陕西西安710021 蒙娜丽莎集团股份有限公司广东佛山528211 广西蒙娜丽莎新材料有限公司广西梧州543000

N型半导体BiVO_(4)是降解有机污染物最具应用前景的可见光光催化材料之一.然而,纯BiVO_(4)由于光生电子-空穴对复合过快,载流子传输速率低等问题限制着其光催化能力.表面活性剂不仅可以调节BiVO_(4)的形貌和粒径大小,还可以通过增大比... 详细信息

N型半导体BiVO_(4)是降解有机污染物最具应用前景的可见光光催化材料之一.然而,纯BiVO_(4)由于光生电子-空穴对复合过快,载流子传输速率低等问题限制着其光催化能力.表面活性剂不仅可以调节BiVO_(4)的形貌和粒径大小,还可以通过增大比表面积来增多反应活性位点,以提高光催化活性.本研究以十二烷基硫酸钠(SDS)为表面活性剂,通过简单的一步水浴法制备出一系列不同摩尔比的SDS/BiVO_(4)光催化剂,并在500 W氙灯下照射降解有机污染物罗丹明B并评价其光催化降解性能.结果表明:10%SDS/BiVO_(4)具有最高的光催化降解效率,BET表征和光电流测试证实了SDS的引入不仅增大了BiVO_(4)的比表面积为光催化反应提供更多的活性位点,而且提高了光生载流子分离和迁移效率.此外,自由基捕获实验表明:·OH和h+在光催化降解罗丹明B过程中是起主要作用的反应基团.该研究方法绿色环保且易于实现,为制备高效可见光光催化剂用于降解有机污染物提供了新思路.

关键词：光催化表面活性剂降解反应有机污染物

维普期刊数据库博看期刊