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Search Results: 1 - 10 of 10767 matches for " DU Yumin "
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Ultra-High Specific Absorption of Metallic Binary-Groove Gratings  [PDF]
Yutong Li, Yumin Liu
Optics and Photonics Journal (OPJ) , 2017, DOI: 10.4236/opj.2017.78B013
Abstract:
A metallic binary-groove gratings, which can be exploited to absorb light at C-band and sense materials with refractive index (1.0 - 1.2), is proposed and investigated numerically. Both ultra-high absorption (99.937%) and sensitivity (1600 nm/RIU) are achieved.
RECENT PROGRESS OF CHITIN-BASED MATERIALS
甲壳素基新材料研究进展

SHI Xiaowen,LI Xiaoxia,DU Yumin,
施晓文
,李晓霞,杜予民

高分子学报 , 2011,
Abstract: Chitin is the most abundant nature resources next to cellulose.Regardless its poor solubility,functional materials developed from chitin are showing great potential in biomedical and biology applications due to its appealing biocompatible and biodegradable properties.Chitosan is the most important derivative of chitin.It is hydrophilic,pH responsive,gel-forming and easy to functionization without losing its biological activity.Films,Fibers,gels and powders are found their applications in various occasions.In this review,chitin and chitosan based functional materials are highlighted.Special interests are focused on recent developments in the filed of catalytic materials,medical nanomaterials,analytic materials,antibacterial and edible packaging materials and environmental materials.It is anticipated that more uses of chitin and chitosan as high value-added biomedical materials will be forthcoming in the near future.
PREPARATION AND DRUG-CONTROLLED RELEASE PROPERTIES OF CARBOXYMETHYL CHITOSAN/ORGANIC RECTORITE NANOCOMPOSITES
羧甲基壳聚糖/有机累托石纳米复合材料及其药物缓释性能研究

WU Xiaoting,WANG Xiaoying,DU Yumin,
吴小婷
,王小英,杜予民

高分子学报 , 2009,
Abstract: In order to combine the advantage of a biopolymer with clay in a drug delivery system,the simple solution-mixing processing technique was used to prepare carboxymethyl chitosan/organic rectorite nanocomposites(COR).The rectorite(REC) was modified with cetyltrimethyl ammonium bromide.A study on these nanocomposites' microstructures and configurations was conducted through observation of Xray diffraction(XRD),fourier transform infrared spectroscopy(FTIR) and scanning electron microscopy(SEM).The results indic...
Aerobic Biodegradation of Starch-containing Polyethylene Films under Controlled Conditions
淀粉聚乙烯膜在受控条件下的好氧生物降解

Lianshuang Zheng,Yumin Du,Jiayao Zhang,
郑连爽
,杜予民,张甲耀

环境科学 , 2000,
Abstract: 采用土埋、真菌生长和 CO2 释放试验分别测定了几种淀粉聚乙烯膜的生物降解性 .试验结果表明 ,膜的生物降解性与膜中的淀粉含量正相关 ,并受膜比面积大小的影响 .在受控条件下 ,含淀粉 6%~ 30 %的膜经 28d降解后 ,降解质量变化率在0.6%~ 12.4%范围内 ,其 CO2 释放量为 0.02~ 0.15mg/mg膜 .膜中的聚乙烯组分不仅本身难被生物降解 ,而且还抑制微生物对其淀粉组分的降解 .CO2 是淀粉聚乙烯膜好氧生物降解的终产物 ,可以作为评估膜生物降解性的一个可靠指标 .
PREDICTION AND CONTROL OF DEPOLYMERIZATION OF CHITOSAN BY SONOLYSIS AND DEGRADATION KINETICS
壳聚糖超声可控降解及降解动力学研究

LI Jin,DU Yumin,YAO Pingjia,WEI Yuan''''an,
李瑾
,杜予民,姚评佳,魏远安

高分子学报 , 2007,
Abstract: Optimal conditions for preparation of low molecular weight chitosan with sonolysis were described.The influence of sonolysis conditions and the molecular parameters of initial chitosan on the degradation rate and degradation rate constant was investigated in detail.Weight-average molecular weight(M_w)and molecular weight distribution(M_w/M_n)of samples were measured by gel permeation chromatography.The structure of degraded chitosan was characterized by Fourier transform infrared spectroscopy and X-ray diffraction.For a given sonolysis time,the decrease in molecular weight has been found to be the greatest at the lowest reaction temperature and lowest chitosan concentration.Molecular weight of samples decreased exponentially with increasing sonication time at early stages.The action mode of ultrasound on the splitting of molecular chains of chitosan was discussed.The degree of deacetylation of the main hydrolysis products almost unchanged compared with the initial chitosan.The decrease of molecular weight led to transformation of crystal structure,but the chemical structures of residues were not modified.Ultrasonic treatment on chitosan is an alternative,safe method to prepare different molecular weight chitosan which is more suitable for biomedical and food applications.
Enantiomeric Separation of 1,4-Dihydro-5-Methoxycarbonyl-2,6-Dimethyl-4-(3-Nitrophenyl)-3-Pyridinecarboxylic Acid Enantiomers
高效液相色谱法拆分1,4-二氢-2,6-二甲基-4-(3-硝基苯基)-3,5-吡啶二羧酸单甲酯对映体

LI Kun,WANG Hairong,WANG Hai,DU Yumin,
李坤
,王海荣,王海,杜玉民

色谱 , 2006,
Abstract: 1,4-二氢-2,6-二甲基-4-(3-硝基苯基)-3,5-吡啶二羧酸单甲酯(简称单甲酯,结构见图1)是1,4.二氢吡啶类药物的一个重要中间体。消旋二氢吡啶类药物很难直接进行化学拆分,光学纯的二氢吡啶类药物多利用单甲酯的单一对映体合成得到。Delee等将蛋白质类手性固定相用于高效液相色谱拆分单甲酯对映体。本文将Chiralpak AD-H直链淀粉氨基甲酸酯类手性固定相用于高效液相色谱直接对单甲酯对映体进行拆分,方法简便、快捷,分离效果较好。
Precision Assessment of UAVRS Based DSM in Disaster Emergency  [PDF]
Yumin Tan, Lingfeng He, Linjie Bai
Advances in Remote Sensing (ARS) , 2016, DOI: 10.4236/ars.2016.53017
Abstract: Ground control point (GCP) is important for georeferencing remotely sensed images and topographic model. However, considering that GCP collection is sometimes a difficult, time-consuming and expensive task with high resolution (HR) data in remote and harsh environments, today unmanned aerial vehicle based remote sensing (UAVRS) is frequently used in geological disaster emergency monitoring and rescuing for its great advantage in collecting timely onsite images. In this paper, for evaluating the feasibility of the UAVRS in disaster emergency and high cut slope safety monitoring, the digital surface model (DSM) without GCPs based on Structure from Motion (SfM) is accessed, and results showed that the geometric accuracy of DSM was smaller than 1 percent, which prove the usefulness of DSM based on UAVRS in emergency. Comparing to normal disaster emergency, the method without GCPs can be more efficient and save the disaster emergency time by neglecting GCPs measurement.
Cloning and Expression of Taq DNA Polymerase Gene in Escherichia coli
Taq DNA耐热聚合酶在大肠杆菌中的克隆和高表达

Du Hansen Ji Chaoneng Xu Mai Ma Congcong Zhen Zuohua Mao Yumin,
杜汉森
,季朝能,徐迈,马匆匆,郑佐华,毛裕民

生物工程学报 , 1996,
Abstract: 从水生栖热菌(Thermus aquaticus)YT-1中分离得到的Taq DNA 聚合酶是一种广泛应用于PCR的耐热DNA聚合酶。由于天然菌株酶产量较低,培养条件要求严格,酶的纯化过程极为繁琐而使产品成本较高,因而促使人们构建适合于大规模生产的基因工程菌株。已有人分别通过不同的途径,使用不同的载体,成功地在大肠杆菌菌株中表达了Taq 耐热DNA聚合酶基因。我们通过与前人不同的途径,把这一基因克隆到大肠杆菌的载体质粒pJLA503上并使其得以高表达,为降低生产成本和进一步研究该酶的各种特性提供了有利条件。
A COMPARATIVE STUDY ON HIGHER ENVIRONMENTAL EDUCATION IN JAPAN AND CHINA
中日高等环境教育比较研究

Deng Nansheng,Yuan Fuhuan,Wei Jinbao,Du Yumin,
邓南圣
,袁福环,韦进宝,杜予民

环境科学学报 , 1998,
Abstract: The environmental education for undergraduates and graduates in Japanese universities for 1980s,early 1990s and after the UN Environmen & Development Conference was researched and analyzed,and compared with the environmental education in Chinese universities.The features of the environmental education in Japanese universities were comprehensiveness of specialties distribution and diversity of installed specialties,and that the knowledge education of the various disciplines is emphasized,the education of the environmental consciousness on global environment and the education of the unity on resources and environment is laid stress on.The features is consulted for the reformation of environmental education in our universities.
Enantiomeric separation of azelnidipine by high performance liquid chromatography with chiral stationary phase
高效液相色谱手性固定相法拆分阿折地平对映体

ZHANG Kai,XUE Na,LI Lin,LI Fan,DU Yumin,
张恺
,薛娜,李林,李凡,杜玉民

色谱 , 2010,
Abstract: A high performance liquid chromatographic (HPLC) method was established for the enantiomeric separation of azelnidipine.Baseline chiral separation of azelnidipine was achieved under normal-phase chromatographic mode using the Chiralpak AD-H chiral column (250 mm×4.6 mm,5.0 μm,Daicel).The influences of the nature of chiral stationary phase,form of the mobile phase,and column temperature on the enantiomeric separation were studied.The optimized chromatographic conditions were hexane-isopropyl alcohol (90∶10,v/v) as the mobile phase with a flow rate of 0.8 mL/min and detection at the wavelength of 254 nm.The column temperature was set at 20 ℃.The resolution of 3.3 for azelnidipine was achieved under the above chromatographic conditions.The method is simple,rapid and with good reproducibility.
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