Shaanxi Normal University

www.snnu.edu.cn
Xi'an, China

Shaanxi Normal University is a key institution of higher education in People's Republic of China authorized to grant degrees in almost all kinds of subject. It was included in the 211 Project in 2006 and started its high-speed development.. Wikipedia.

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News Article | May 4, 2017
Site: www.eurekalert.org

The Badain Jaran Desert is located in the arid region of northwest China, and is a unique landscape characterised by more than 140 lakes as well as extensive megadunes (Figure 1), including the highest dune in the world. In 2009, the United Nations Educational, Scientific and Cultural Organization approved the Badan Jaran Desert Scenic Area, the Tengger Desert Scenic Area and Juyanhai Scenic Area as the "Alxa Desert World Geopark". Since the beginning of the 20th century, the unique natural landscape of Badain Jaran Desert has received considerable research attention, especially whether the about 90mm of atmospheric precipitation in the region can serve as a source of water for many lakes have been the focus of controversy. A recent research work revealed that atmospheric precipitation in the Badain Jaran Desert recharges the lake water. This research work, entitled "The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance", coauthored with Jingbo Zhao, Yandong Ma, Xiaoqing Luo, Dapeng Yue, Tianjie Shao and Zhibao Dong, scholars at Shaanxi Normal University, was published in the Science China Earth Sciences, No. 4, 2017. The researchers obtained a number of important new discoveries through field surveys in the Badain Jaran Desert, such as physical and chemical deposits produced by surface runoff on the slopes of megadunes, rarely-seen infiltration-excess surface runoff in the megadune depressions and spring streams at the base of megadunes, and used electron microscopy, energy spectrum analysis, infiltration experiments, moisture content determinations and grain-size analysis to study the mineral and chemical composition of the runoff precipitates, and grain-size of the deposits associated with the runoff, together with the hydrological balance in the megadune area, and the atmospheric precipitation mechanism responsible for groundwater recharge and for supplying water to lakes. Several lines of evidence, such as the physical and chemical deposits resulting from shallow subsurface runoff, spring streams, infiltration-excess runoff, and gravity capillary water with a moisture content of 3%-6%, demonstrate that the hydrological cycle in this region is characterized by atmospheric precipitation-soil water-groundwater-surface water conversion model (Figure 2), that is, atmospheric precipitation reaches the base of the megadunes through infiltration and subsequently becomes groundwater and lake water. The result of this study is of great scientific significance in explaining the source of lake water in the Badain Jaran Desert, is of great practical significance to the scientific utilization of groundwater resources in this region, and is of great reference value in research on the hydrological cycle, including groundwater recharge conditions and recharge mechanisms, in desert region. This research was funded by the Major Projects of International Cooperation of National Natural Science Foundation of China (Nos. 41210002 and 40672108) and the Cheung Kong Scholars Programme of the Ministry of Education of China (No. 801813) See the article: J. Zhao, Y. Ma, X. Luo, D. Yue, T. Shao, Z. Dong, "The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance," Sci. China Earth Sci., (2017) 60(4): 707-719. doi:10.1007/s11430-016-9019-2 This article was published online , in the Science China Earth Sciences, by Science China Press and Springer-Verlag Berlin Heidelberg.


Xu L.-W.,Hangzhou Normal University | Xu L.-W.,Shaanxi Normal University
ChemCatChem | Year: 2013

This minireview focuses on the recent advances in the synthetic application of amino acid-derived bifunctional phosphine catalysts bearing a hydrogen-bond donor. In the examples illustrated, the amino acid-based phosphines have already been proven to be versatile, catalyzing a wide range of asymmetric reactions, including (aza)-MBH reactions, [3+2] cyclizations, [4+2] cycloadditions, allylic alkylation, and Michael addition. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gao Y.,Shaanxi Normal University | Li B.,Shaanxi Normal University
Analytical Chemistry | Year: 2014

Detection of ultralow concentrations of specific nucleic acid sequences is a central challenge in the early diagnosis of genetic diseases and biodefense applications. Herein, we report a simple and homogeneous chemiluminescence (CL) method for ultrasensitive DNA detection. It is based on the exonuclease III (Exo III)-assisted cascade signal amplification and the catalytic effect of G-quadruplex-hemin DNAzyme on the luminol-H2O2 CL system. A quadruplex-forming DNA probe hybridizes a hairpin DNA probe to construct a duplex DNA probe as recognition element. Upon sensing of target DNA, the recognition of target DNA and the duplex DNA probe triggers the Exo III cleavage process, accompanied by releasing target DNA and generating a new secondary target DNA fragment. The released target DNA and the secondary target DNA are recycled. Simultaneously, numerous quadruplex-forming sequences are liberated and bind hemin to yield G-quadruplex-hemin DNAzyme, which subsequently catalyze the luminol-H2O2 reaction to produce strong CL emission. This method exhibited a high sensitivity toward target DNA with a detection limit of 8 fM, which was about 100 times lower than that of the reported DNAzyme-based colorimetric system for DNA detection with Exo III-assisted cascade signal amplification. This method provides a simple, isothermal, and low-cost approach for sensitive detection of DNA and holds a great potential for early diagnosis in gene-related diseases. © 2014 American Chemical Society.


Cao R.,Shaanxi Normal University | Li B.,Shaanxi Normal University
Chemical Communications | Year: 2011

The electrostatic interaction between the negatively-charged heparin and the positively-charged gold nanoparticles leads to aggregation of gold nanoparticles and a color change from red to blue in solution, thus providing a simple and visual approach to colorimetric detection of heparin. © The Royal Society of Chemistry.


Liu Z.-H.,Shaanxi Normal University
Carbon | Year: 2010

A hybrid graphene/Ni2+-Fe3+ layered double hydroxide material has been fabricated by the hydrothermal treatment of a mixed suspension of the exfoliated graphite oxide, Ni(NO3)2 6H 2O, Fe(NO3)3·9H2O, urea and trisodium citrate. The Ni2+-Fe3+ layered double hydroxide platelets are first homogeneously grown on the surface of GO nanosheets which are then reduced to graphene under a mild hydrothermal treatment. In the hybrid graphene/Ni2+-Fe3+ layered double hydroxide material, the restacking of graphene nanosheets is effectively prevented by the formation of Ni2+-Fe3+ layered double hydroxide platelets, and the graphene nanosheets exist in a complete exfoliation state. © 2010 Elsevier Ltd. All rights reserved.


Detection of ultralow concentration of specific nucleic acid sequences is important in early diagnosis of gene-related diseases and biodefense application. Herein, we report an amplified chemiluminescence (CL) biosensing platform for ultrasensitive DNA detection. It is based on the exonuclease III-assisted target recycling amplification and catalytic effect of G-quadruplex-hemin DNAzyme to stimulate the generation of CL in the presence of H2O2 and luminol. Moreover, the typical problem of high background induced by excess hemin itself can be effectively addressed through the absorbing of superfluous hemin on the surface of single-walled carbon nanotubes and then removing though centrifugation. Therefore, our proposed biosensing exhibited a high sensitivity toward target DNA with a detection limit of 12 fM, which was about 100-fold lower than that of the DNAzyme-based CL sensor for DNA detection without Exo III-assisted amplification. This sensing platform provides a label-free and cost-effective approach for sensitive detection of DNA. © 2013 American Chemical Society.


Yang P.,Shaanxi Normal University | Yang W.,Beijing University of Chemical Technology
Chemical Reviews | Year: 2013

Researchers discuss chemoselective phototransformation of C-H bonds on organic polymeric materials and related high-tech applications. New demands on polymer surfaces have led chemists to develop chemical systems that can directly convert C-H bonds on these soft organic material surfaces into functional groups or polymer chains in facile, efficient, specific, and selective ways. Several methods have been established for C-H transformations in molecules based on the use of different catalysts such as transition metal complexes, enzymes, and pure organic compound-catalyzed coupling methods. Examples based on photochemistry have emerged to achieve chemoselective activation of C-H bonds, which have become the emphasis of extensive discussion and summary. Top-down techniques such as photochemistry, which facilitate the preparation of gradient surfaces, have also found a wide range of applications in high-tech fields.


Ding L.,Shaanxi Normal University | Fang Y.,Shaanxi Normal University
Chemical Society Reviews | Year: 2010

The development of fluorescent chemical sensors has been an active research topic for many research fields. Design strategies play an important role in the sensing performance of the desired sensors. The use of chemically assembled monolayers of fluorophores to fabricate film sensors has shown several advantages: highly stable, re-useable, non-consumptive, and easy to be made into devices, etc. The present tutorial review gives an overview of the fluorescent film sensors based on chemical monolayer assemblies of fluorophores that have been developed in our laboratory along with some representative publications of others over the past decade. Different sensing mechanisms were taken into account in the sensor designs, including hydrogen-bond formation, static complex with quenchers, and more interestingly, the "spacer layer screening effect". Various neutral organic chemicals and anions were targeted by these film sensors with great selectivity and sensitivity. In particular, the specific "spacer layer screening effect" imparts these particular type of films with tuned selectivity, opening a novel direction in developing fluorescent film sensors. © 2010 The Royal Society of Chemistry.


Li Y.,Shaanxi Normal University
Information Sciences | Year: 2011

In this paper, we study finite automata with membership values in a lattice, which are called lattice-valued finite automata. The extended subset construction of lattice-valued finite automata is introduced, then the equivalences between lattice-valued finite automata, lattice-valued deterministic finite automata and lattice-valued finite automata with -moves are proved. A simple characterization of lattice-valued languages recognized by lattice-valued finite automata is given, then it is proved that the Kleene theorem holds in the frame of lattice-setting. A minimization algorithm of lattice-valued deterministic finite automata is presented. In particular, the role of the distributive law for the truth valued domain of finite automata is analyzed: the distributive law is not necessary to many constructions of lattice-valued finite automata, but it indeed provides some convenience in simply processing lattice-valued finite automata. © 2010 Elsevier Inc. All rights reserved.


Patent
Shaanxi Normal University | Date: 2016-06-24

The present invention discloses a restoration solution for cine film bubble and a restoration method. The restoration solution comprises 100 parts by volume of n-butanol, 60 to 120 parts by volume of lacquer thinner having 5% by mass of ethyl cellulose, 8 to 20 parts by volume of diphenyl isooctyl phosphite, 2 to 10 parts by volume of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and 2 to 15 parts by volume of petroleum ether. The present invention integrates micro-restoration, bubble puncture and optical filling, and effectively restores a bubble having a diameter of 0.1 mm to 1 mm generated between a film base layer and an emulsion layer of a cine film. The present invention has advantages of simple method of operation, low cost and good controllability. And the used restoration solution has good thermal stability, oxidation resistance, and permeability, and can eliminate the phenomenon of light scattering within the bubble, so that patterns and writing of the original image data are explicitly presented, and a better restoration effect is achieved without damages to films. Therefore, the restoration solution has good application values and market prospects.

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