Chlorobenzene is a model molecule for researching harmful chlorinated volatile organic compounds.Designing the chemical adsorption site for complex molecules such as chlorobenzene is challenging without a large datase...Chlorobenzene is a model molecule for researching harmful chlorinated volatile organic compounds.Designing the chemical adsorption site for complex molecules such as chlorobenzene is challenging without a large dataset and reasonable descriptors.Here,the adsorption of chlorobenzene on a phosphorylated CeO_(2)catalyst was analyzed using density functional theory calculations.Three different surface phosphate(H_(x)PO_(4))models were constructed and used to adsorb chlorobenzene.An orbital interaction with fully occupied antibonding is found in one of three physical adsorptions.Based on this,the surface sites of a tri-cluster(M_(3))located at the CeO_(2)surface have been suggested to activate chlorobenzene.Three different clusters have been tested,namely Fe_(3),Ru_(3),and B_(3).All these clusters can activate and twist chlorobenzene by donating electrons.Fe_(3)and Ru_(3)form bonds with weak covalent and strong ionic characters,while B3forms strong covalent bonds between boron and carbon.This work not only predicts a class of sites for chlorobenzene activation that may prevent polychlorinated by-products but also gives a template for catalyst rational design according to fundamental catalytic theory.展开更多
Tri-training利用无标签数据进行分类可有效提高分类器的泛化能力,但其易将无标签数据误标,从而形成训练噪声。提出一种基于密度峰值聚类的Tri-training(Tri-training with density peaks clustering,DPC-TT)算法。密度峰值聚类通过类...Tri-training利用无标签数据进行分类可有效提高分类器的泛化能力,但其易将无标签数据误标,从而形成训练噪声。提出一种基于密度峰值聚类的Tri-training(Tri-training with density peaks clustering,DPC-TT)算法。密度峰值聚类通过类簇中心和局部密度可选出数据空间结构表现较好的样本。DPC-TT算法采用密度峰值聚类算法获取训练数据的类簇中心和样本的局部密度,对类簇中心的截断距离范围内的样本认定为空间结构表现较好,标记为核心数据,使用核心数据更新分类器,可降低迭代过程中的训练噪声,进而提高分类器的性能。实验结果表明:相比于标准Tritraining算法及其改进算法,DPC-TT算法具有更好的分类性能。展开更多
Water-solube iron-sulfur cluster nanoparticles were synthesized by using tri-sodium citrate as a stabilizer. The effect of factors such as the amount of reactants, the type of reactants, pH value, dripping order was s...Water-solube iron-sulfur cluster nanoparticles were synthesized by using tri-sodium citrate as a stabilizer. The effect of factors such as the amount of reactants, the type of reactants, pH value, dripping order was studied on the formation of iron-sulfur cluster nanoparticles. The structure, photo- and electro- chemical performance were characterized by UV-Vis, Raman, TEM, ED, EDS and Cyclic Voltammetry were used to characterize the structure and properties. The UV-Vis peaks at 436, 532 and 636 nm are attributed to the characteristic peaks of [4Fe-4S]+ and [2Fe-2S]2+. The Raman results indicate that citrate anions have been adsorbed on the surface of iron-sulfur cluster nanoparticles. TEM image shows the particles are about 5 nm, and EDS result further proves that iron-sulfur cluster coated by tri-sodium citrate has been obtained. Cyclic Voltammetry result demonstrates that iron-sulfur cluster has similar electrochemical property to that in organism.展开更多
研究蛋白质寡肽构象在构象空间中的分布情况,对提取寡肽模式并构建短肽库具有重要意义。通过构建一个保距映射,将以主链原子均方根距离(root mean square distance,RMSD)为距离测度的三肽构象空间变换为一维直线上的欧氏距离空间,从而...研究蛋白质寡肽构象在构象空间中的分布情况,对提取寡肽模式并构建短肽库具有重要意义。通过构建一个保距映射,将以主链原子均方根距离(root mean square distance,RMSD)为距离测度的三肽构象空间变换为一维直线上的欧氏距离空间,从而直观地展现三肽构象的聚集情况,表明三肽主链构象可以用单一变量编码。应用该特性对四肽的构象空间加以分析,将四肽构象映射到三维空间中,从而以可视的方式描述四肽构象空间的聚集情况。对短肽构象空间的初步分析表明,短肽的聚集性和二级结构有着密切的联系。在四肽构象空间中存在有自然边界的离散区域(与螺旋等结构相关),也有一些区域(与折叠等结构有关)难以进一步划分。这种方法也为以可视方式分析高维空间中肽段的聚集性给出了一种可能的方案。展开更多
Through the reaction of Co 2(CO) 8 with four ligands containing P ?S? N atoms, cobalt carbonyl sulfur clusters Co 3(CO) 7( μ 3-S)〔 μ,η 2 -CNC(CH 3) 2P(S)(Cl)N(Ph)](Ⅰ)and Co 3 (CO) 7( μ 3-S)〔 μ,η 2 -SC(NH2)N-N...Through the reaction of Co 2(CO) 8 with four ligands containing P ?S? N atoms, cobalt carbonyl sulfur clusters Co 3(CO) 7( μ 3-S)〔 μ,η 2 -CNC(CH 3) 2P(S)(Cl)N(Ph)](Ⅰ)and Co 3 (CO) 7( μ 3-S)〔 μ,η 2 -SC(NH2)N-N=CH-C 6H 5〕 (Ⅱ),two tetranu-clear cobalt carbonyl clusters Co 4(CO) 10( μ 4 -S)( μ 4 -PC 6H 4OCH 3)(Ⅲ) and Co 4(CO) 10( μ 4-S)( μ 4-PC 6H 4OC 2H 5)(Ⅳ) ,were prepared and characterized by elementary analysis?IR? 1HNMR and MS spectroscopy.It was shown that bothⅠand Ⅱ have a tetrahedral framework Co 3S , both Ⅲ and Ⅳ have a octahedral framework Co 4SP. (Ⅰ)and Co 3 (CO) 7( μ 3-S)〔 μ,η 2 -SC(NH2)N-N=CH-C 6H 5〕 (Ⅱ),two tetranu-clear cobalt carbonyl clusters Co 4(CO) 10( μ 4 -S)( μ 4 -PC 6H 4OCH 3)(Ⅲ) and Co 4(CO) 10( μ 4-S)( μ 4-PC 6H 4OC 2H 5)(Ⅳ) ,were prepared and characterized by elementary analysis?IR? 1HNMR and MS spectroscopy.It was shown that bothⅠand Ⅱ have a tetrahedral framework Co 3S , both Ⅲ and Ⅳ have a octahedral framework Co 4SP.展开更多
基金the support from the National Key Research and Development Program of China(No.2023YFA1508500)the National Natural Science Foundation of China(No.22276120)。
文摘Chlorobenzene is a model molecule for researching harmful chlorinated volatile organic compounds.Designing the chemical adsorption site for complex molecules such as chlorobenzene is challenging without a large dataset and reasonable descriptors.Here,the adsorption of chlorobenzene on a phosphorylated CeO_(2)catalyst was analyzed using density functional theory calculations.Three different surface phosphate(H_(x)PO_(4))models were constructed and used to adsorb chlorobenzene.An orbital interaction with fully occupied antibonding is found in one of three physical adsorptions.Based on this,the surface sites of a tri-cluster(M_(3))located at the CeO_(2)surface have been suggested to activate chlorobenzene.Three different clusters have been tested,namely Fe_(3),Ru_(3),and B_(3).All these clusters can activate and twist chlorobenzene by donating electrons.Fe_(3)and Ru_(3)form bonds with weak covalent and strong ionic characters,while B3forms strong covalent bonds between boron and carbon.This work not only predicts a class of sites for chlorobenzene activation that may prevent polychlorinated by-products but also gives a template for catalyst rational design according to fundamental catalytic theory.
文摘Tri-training利用无标签数据进行分类可有效提高分类器的泛化能力,但其易将无标签数据误标,从而形成训练噪声。提出一种基于密度峰值聚类的Tri-training(Tri-training with density peaks clustering,DPC-TT)算法。密度峰值聚类通过类簇中心和局部密度可选出数据空间结构表现较好的样本。DPC-TT算法采用密度峰值聚类算法获取训练数据的类簇中心和样本的局部密度,对类簇中心的截断距离范围内的样本认定为空间结构表现较好,标记为核心数据,使用核心数据更新分类器,可降低迭代过程中的训练噪声,进而提高分类器的性能。实验结果表明:相比于标准Tritraining算法及其改进算法,DPC-TT算法具有更好的分类性能。
文摘Water-solube iron-sulfur cluster nanoparticles were synthesized by using tri-sodium citrate as a stabilizer. The effect of factors such as the amount of reactants, the type of reactants, pH value, dripping order was studied on the formation of iron-sulfur cluster nanoparticles. The structure, photo- and electro- chemical performance were characterized by UV-Vis, Raman, TEM, ED, EDS and Cyclic Voltammetry were used to characterize the structure and properties. The UV-Vis peaks at 436, 532 and 636 nm are attributed to the characteristic peaks of [4Fe-4S]+ and [2Fe-2S]2+. The Raman results indicate that citrate anions have been adsorbed on the surface of iron-sulfur cluster nanoparticles. TEM image shows the particles are about 5 nm, and EDS result further proves that iron-sulfur cluster coated by tri-sodium citrate has been obtained. Cyclic Voltammetry result demonstrates that iron-sulfur cluster has similar electrochemical property to that in organism.
文摘研究蛋白质寡肽构象在构象空间中的分布情况,对提取寡肽模式并构建短肽库具有重要意义。通过构建一个保距映射,将以主链原子均方根距离(root mean square distance,RMSD)为距离测度的三肽构象空间变换为一维直线上的欧氏距离空间,从而直观地展现三肽构象的聚集情况,表明三肽主链构象可以用单一变量编码。应用该特性对四肽的构象空间加以分析,将四肽构象映射到三维空间中,从而以可视的方式描述四肽构象空间的聚集情况。对短肽构象空间的初步分析表明,短肽的聚集性和二级结构有着密切的联系。在四肽构象空间中存在有自然边界的离散区域(与螺旋等结构相关),也有一些区域(与折叠等结构有关)难以进一步划分。这种方法也为以可视方式分析高维空间中肽段的聚集性给出了一种可能的方案。
基金Supported by the National Natural Science Foundation of China under Grant Nos.60702033 60772076 (国家自然科学基金)+3 种基金the National High-Tech Research and Development Plan of China under Grant No.2007AA01Z171 (国家高技术研究发展计划(863)the Science Fund for Distinguished Young Scholars of Heilongjiang Province of China under Grant No.JC200611 (黑龙江省杰出青年科学基金)the Natural Science Foundation of Heilongjiang Province of China under Grant No.ZJG0705 (黑龙江省自然科学重点基金)the Foundation of Harbin Institute of Technology of China under Grant No.HIT.2003.53 (哈尔滨工业大学校基金)
文摘Through the reaction of Co 2(CO) 8 with four ligands containing P ?S? N atoms, cobalt carbonyl sulfur clusters Co 3(CO) 7( μ 3-S)〔 μ,η 2 -CNC(CH 3) 2P(S)(Cl)N(Ph)](Ⅰ)and Co 3 (CO) 7( μ 3-S)〔 μ,η 2 -SC(NH2)N-N=CH-C 6H 5〕 (Ⅱ),two tetranu-clear cobalt carbonyl clusters Co 4(CO) 10( μ 4 -S)( μ 4 -PC 6H 4OCH 3)(Ⅲ) and Co 4(CO) 10( μ 4-S)( μ 4-PC 6H 4OC 2H 5)(Ⅳ) ,were prepared and characterized by elementary analysis?IR? 1HNMR and MS spectroscopy.It was shown that bothⅠand Ⅱ have a tetrahedral framework Co 3S , both Ⅲ and Ⅳ have a octahedral framework Co 4SP. (Ⅰ)and Co 3 (CO) 7( μ 3-S)〔 μ,η 2 -SC(NH2)N-N=CH-C 6H 5〕 (Ⅱ),two tetranu-clear cobalt carbonyl clusters Co 4(CO) 10( μ 4 -S)( μ 4 -PC 6H 4OCH 3)(Ⅲ) and Co 4(CO) 10( μ 4-S)( μ 4-PC 6H 4OC 2H 5)(Ⅳ) ,were prepared and characterized by elementary analysis?IR? 1HNMR and MS spectroscopy.It was shown that bothⅠand Ⅱ have a tetrahedral framework Co 3S , both Ⅲ and Ⅳ have a octahedral framework Co 4SP.
