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Search Results: 1 - 10 of 195610 matches for " CHEN qing-li "
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Preparation of Acicular Nanocrystalline Mg,Al-hydrotalcite by LiquidMethod
液相法合成针状镁铝水滑石纳米晶的研究

REN Qing-Li,CHEN Wei,LUO Qiang,
任庆利
,陈维,罗强

无机材料学报 , 2004,
Abstract: 研究了合成条件(原料种类、加料次序、NaOH浓度和合成温度)对液相法制备镁铝水滑石试样的相组成的影响.以MgCl2为镁源、NaAlO2为铝源、NaCO3和NaOH为沉淀剂,在常压下采用液相法制备了长度约100nm、直径约10nm的Mg6Al2(OH)16CO3-4H2O针状纳米晶体.并且发现:可溶性原料的选取、最后加入MgCl2的加料次序、>45℃的合成温度和保证反应溶液的pH>12,是瞬间生成镁铝水滑石纳米晶的充分必要条件.提出镁铝水滑石纳米晶核形成的过程是:均匀分布于溶液中的Al13(OH)32 7+迅速吸附于带羟基OH-的无定型态的Mg(OH)2表面,并进行Al3+扩散,为平衡电价,CO32-也扩散进入Mg(OH)2,从而在瞬间完成镁铝水滑石晶核的形成.
A convenient implementation of the overlap between arbitrary Hartree-Fock-Bogoliubov vacua for projection
Zao-Chun Gao,Qing-Li Hu,Y. S. Chen
Physics , 2013, DOI: 10.1016/j.physletb.2014.04.012
Abstract: Overlap between Hartree-Fock-Bogoliubov(HFB) vacua is very important in the beyond mean-field calculations. However, in the HFB transformation, the $U,V$ matrices are sometimes singular due to the exact emptiness ($v_i=0$) or full occupation ($u_i=0$) of some single-particle orbits. This singularity may cause some problem in evaluating the overlap between HFB vacua through Pfaffian. We found that this problem can be well avoided by setting those zero occupation numbers to some tiny values (e.g., $u_i,v_i=10^{-8}$). This treatment does not change the HFB vacuum state because $u_i^2,v_i^2=10^{-16}$ are numerically zero relative to 1. Therefore, for arbitrary HFB transformation, we say that the $U,V$ matrices can always be nonsingular. From this standpoint, we present a new convenient Pfaffian formula for the overlap between arbitrary HFB vacua, which is especially suitable for symmetry restoration. Testing calculations have been performed for this new formula. It turns out that our method is reliable and accurate in evaluating the overlap between arbitrary HFB vacua.
Matrix elements of one-body and two-body operators between arbitrary HFB multi-quasiparticle states
Qing-Li Hu,Zao-Chun Gao,Y. S. Chen
Physics , 2013, DOI: 10.1016/j.physletb.2014.05.045
Abstract: We present new formulae for the matrix elements of one-body and two-body physical operators in compact forms, which are applicable to arbitrary Hartree-Fock-Bogoliubov wave functions, including those for multi-quasiparticle excitations. The test calculations show that our formulae may substantially accelerate the process of symmetry restoration when applied to the heavy nuclear system.
Optimization of clear liquid fermentation condition for ethanol production from Canna edulis Kerl  [PDF]
Ying Shen, Qing-li Tang, Tian-Xiang Wu
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.22019
Abstract: In this paper, clear liquid fermentation condition for ethanol production from Canna edulis Kerl with orthogonal design was studied. We have studied five factors that influenced clear liquid fermentation condition for ethanol production from Canna edulis Kerl by the single-factor test. The five factors were α-amylase amount, glu-coamylase amount, pH, nitrogen and auxiliary materials amount. Selected the best amounts of α-amylase, glucoamylase, pH, nitrogen source and auxiliary materials by means of the singe- factors test. And then, we used the Orthogonal test to optimize the fermentation process. The study showed that the best fermentation condi-tions were α-amylase amount 7 u/g C.eduli, glu-coamylase amount 145u/g C. edulis, pH 4.4 and the amount of urea 0.08%, 1% of rice bran as auxiliary materials. The rate of alcohol which was produced by the best fermentation conditions is 21.5% that increased by 1.3% than the rate of alcohol by the single-factor test.
Chemical Profiling and Quantification of Isoflavone Phytoestrogens in Kudzu Using LC/UV/MSD  [PDF]
Qing-Li Wu, Yong-Hong Yang, Jim Simon
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.26076
Abstract: Method development for determination of isoflavones in kudzu was achieved by HPLC/UV/ESI-MSD. Us- ing three kudzu species of Pueraria lobata, P. thomsonii and P. edulis, and analyzing the isoflavones sepa- rately by species and from different plant tissues (roots, stems, leaves, flowers and fruits) in each species, a total of 25 isoflavones were identified by their molecular ions and characteristic fragment ion peaks using LC/MSD under MS and MS/MS mode, and in comparison with standard isoflavones. Two main chemical groups were identified: 1) 8-C-glycosyl isoflavone of puerarin and the analogues of 5-OH puerarin, 3’-OH puerarin, 3’-OMe puerarin, and their glycosides; and 2) daidzein, genistein, glycitein and their glycosyl and malonyl derivatives, which are similar to those known in soy. To accurately quantitate total isoflavones, acidic hydrolysis during extraction of kudzu samples was applied to convert the oxygen glycosides into their respective isoflavone aglycones of daidzein, genistein and glycitein, or non-hydrolyzed carbon glycosides of puerarin, 5-OH puerarin, 3’-OH puerarin and 3’-OMe puerarin. Under the multiple optimized conditions, all seven isoflavones in acidic hydrolyzed kudzu extracts were successfully separated within 30 min and quanti- fied individually with calycosin used as internal standard by both UV and MS detectors. For the quantitative study, several standards e.g. 5-OH puerarin, 3’-OH puerarin and 3’-OMe puerarin are not commercially available. Using polyamide, sephdex-LH20 chromatography and Prep-HPLC, we purified these three stan- dards from kudzu extracts and then elucidated their structures by UV, MS and NMR spectrometric methods. This is the first method to simultaneously quantitate all the isoflavones in kudzu.
Efficient CT Metal Artifact Reduction Based on Fractional-Order Curvature Diffusion
Yi Zhang,Yi-Fei Pu,Jin-Rong Hu,Yan Liu,Qing-Li Chen,Ji-Liu Zhou
Computational and Mathematical Methods in Medicine , 2011, DOI: 10.1155/2011/173748
Abstract: We propose a novel metal artifact reduction method based on a fractional-order curvature driven diffusion model for X-ray computed tomography. Our method treats projection data with metal regions as a damaged image and uses the fractional-order curvature-driven diffusion model to recover the lost information caused by the metal region. The numerical scheme for our method is also analyzed. We use the peak signal-to-noise ratio as a reference measure. The simulation results demonstrate that our method achieves better performance than existing projection interpolation methods, including linear interpolation and total variation. 1. Introduction Metal artifact reduction (MAR) is still one of the major challenges in X-ray computed tomography (CT) imaging [1–6]. For high density objects, such as a metal object, the severe attenuation of X-rays allows only a limited number of photos to reach the receiving CT array of sensors. As a result, streak artifacts appear in the reconstructed image after filtered back projection (FBP). The artifacts spread through the whole image, thereby contaminating the imaging quality. Since the projection data of the metal regions are much larger than ordinary tissue projection data sets, we can assume that the segments of the sinogram with the metal projection data sets are dominated by the metal component only. Based on this assumption, we can deal with projection data of metal objects as lost information, using one of the two main categories of methods: projection interpolation methods [7–12] or iterative reconstruction methods [13–17]. After theoretical analysis, MAR methods based on iterative reconstruction have better reconstruction performance than projection interpolation methods, but they often incur high computational costs and are difficult to implement in current CT imaging systems. In this paper, we concentrate on projection interpolation methods for MAR. In 1978, Lewitt and Bates used a Chebyshev polynomial to implement interpolation [7]. Kalender et al. employed linear interpolation (LI) [8], while Crawford added various assistant processes based on it [9]. Also based on linear interpolation, Gu et al. presented a more accurate metal region segmentation method using the differences in neighboring pixels [10]. Zhao et al. proposed interpolating the wavelet coefficients of the projection data [11]. To obtain a better visual effect, inpainting based on partial differential equations (PDEs) was introduced in [12, 13]. The inpainting method proposed by Gu et al. is based on Euler's elastica and curvature [12]. Duan et al.
Effects of CaO-modified zeolite on one-step synthesis of dimethyl ether
浆态床合成二甲醚复合催化剂失活原因探索

Qing-li XU,Ting-chen LI,Yong-jie YAN,
王东升
,谭猗生,韩怡卓,椿范立

燃料化学学报 , 2008,
Abstract: Synthesis of dimethyl ether (DME) was carried out in a fixed bed reactor over a bifunctional catalyst CaO/HZSM-5+JC207, which was composed of a methanol-synthesis catalyst JC207 (Jingjing Catalyst Plant, China) and a dehydrator HZSM-5 (Si/Al = 38) modified with CaO. The effects of zeolite modification with CaO on the performance of the bifunctional catalyst in one-step synthesis of DME were investigated. XRD analysis of the modified zeolite CaO/HZSM-5 indicates that CaO is highly dispersed on the zeolite HZSM-5 without any new species formed. Pyridine-IR analysis shows that the modification of HZSM-5 with CaO not only brings on significant changes in acid type and acid amount but also turns some of Bronstead acid sites into Lewis acid sites. NH3-temperature programming desorption analysis indicates that the number of acid sites on the zeolite surface, especially, that of the strong acid sites decreases with the increase of CaO loading. Modification of zeolite HZSM-5 with appropriate dose of CaO turns the strong acid sites into weak or less strong acid sites; such a redistribution of acid sites may be beneficial for the increase of DME selectivity.
One-step synthesis of dimethyl ether over a bi-functional catalyst containing CaO-modified HZSM-5
氧化钙改性分子筛对一步法合成二甲醚的影响(英)

XU Qing-li,LI Ting-chen,YAN Yong-jie,
许庆利
,李廷琛,颜涌捷

燃料化学学报 , 2008,
Abstract: Synthesis of dimethyl ether (DME) was carried out in a fixed bed reactor over a bifunctional catalyst CaO/HZSM-5 JC207,which was composed of a methanol-synthesis catalyst JC207 (Jingjing Catalyst Plant,China) and a dehydrator HZSM-5 (Si/Al = 38) modified with CaO. The effects of zeolite modification with CaO on the performance of the bifunctional catalyst in one-step synthesis of DME were investigated. XRD analysis of the modified zeolite CaO/HZSM-5 indicates that CaO is highly dispersed on the zeolite HZSM-5 without any new species formed. Pyridine-IR analysis shows that the modification of HZSM-5 with CaO not only brings on significant changes in acid type and acid amount but also turns some of Bronstead acid sites into Lewis acid sites. NH3-temperature programming desorption analysis indicates that the number of acid sites on the zeolite surface,especially,that of the strong acid sites decreases with the increase of CaO loading. Modification of zeolite HZSM-5 with appropriate dose of CaO turns the strong acid sites into weak or less strong acid sites;such a redistribution of acid sites may be beneficial for the increase of DME selectivity.
Major Advances in the Research on the Genesis of Excess Argon in High Pressure Muscovite
高压白云母中过剩氩的成因研究进展

CHEN Wen,ZHANG Yan,WANG Qing-li,LIU Xin-yu,
陈文
,张彦,王清利,刘新宇

地球学报 , 2005,
Abstract: 高压白云母中过剩氩成因研究目前已经取得了如下进展:①已经将高压白云母中过剩氩的来源限定为由流体输送和由母岩继承两种;②高压白云母中过剩氩的赋存和矿物的Mg/(Fe+Mg)比值、Si^4+含量及矿物的显微结构有关;③初步认定高压白云母中过剩氩的赋存和岩性有关:榴辉岩中的白云母含过剩氩最多,高压副片麻岩中白云母仍含有少量过剩氩,高压正片麻岩中白云母不含过剩氩。
Cloning and analysis of phosphoenolpyruvate carboxylase gene from Suaeda glauca
碱蓬PEPCase基因的克隆与分析

CHEN Ming-na,YANG Qing-li,YU Shan-lin,QIN Song,
陈明娜
,杨庆利,禹山林,秦松

海洋科学 , 2009,
Abstract: 采用cDNA末端快速扩增(RACE)技术首次获得碱蓬(Suaeda glauca)中含PEPCase基因完整编码区的cDNA序列,长度为3 038 bp.获得的序列采用生物信息学方法和系统进化方法进行分析.结果表明,获得的cDNA序列包含2 898 bp的完整开放阅读框,编码的966个氨基酸序列含有两个PEPCase活性位点以及6种其他的活性位点;预测蛋白质的相对分子质量为109 785.3,等电点为5.51,属于不稳定的亲水性蛋白;含量相对较多的氨基酸是Leu、Glu、Arg、Asp、Ser,不含Pyl和Sec;不包含跨膜结构和信号肽序列,推断为非分泌性蛋白;二级结构以α螺旋为主,三级结构为紧密球状结构;分析结果还表明获得的碱蓬PEPCase基因应该属于C3型.通过对碱蓬PEPCase基因的克隆及序列分析从而为后期碱蓬PEPCase蛋白表达的研究及获得高油量的转基因碱蓬植株奠定了基础.
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