First order least squares method with weakly imposed boundary condition for convection dominated diffusion problems

We present and analyze a first order least squares method for convection dominated diffusion problems, which provides robust L2 a priori error estimate for the scalar variable even if the given data f in L2 space. The novel theoretical approach is to rewrite the method in the framework of discontinuous Petrov - Galerkin (DPG) method, and then show numerical stability by using a key equation discovered by J. Gopalakrishnan and W. Qiu [Math. Comp. 83(2014), pp. 537-552]. This new approach gives an alternative way to do numerical analysis for least squares methods for a large class of differential equations. We also show that the condition number of the global matrix is independent of the diffusion coefficient. A key feature of the method is that there is no stabilization parameter chosen empirically. In addition, Dirichlet boundary condition is weakly imposed. Numerical experiments verify our theoretical results and, in particular, show our way of weakly imposing Dirichlet boundary condition is essential to the design of least squares methods - numerical solutions on subdomains away from interior layers or boundary layers have remarkable accuracy even on coarse meshes, which are unstructured quasi-uniform

TNF-α及TNF-α抗体对破骨细胞V-ATP酶的影响

目的研究不同浓度的TNF-α及TNF-α抗体对破骨细胞上V-ATP酶表达量的影响。方法体外诱导小鼠RAW264.7细胞分化为破骨细胞,通过抗酒石酸酸性磷酸酶染色检测破骨细胞生成情况。然后将破骨细胞分为对照组、TNF-α干预组及TNF-α抗体干预组,TNF-α干预组、TNF-α抗体干预组分别用低、中、高三种浓度的TNF-α、TNF-α抗体干预48 h。用实时荧光定量聚合酶链反应(real-time PCR)、Western blot检测破骨细胞V-ATP酶的mRNA和蛋白表达水平。结果 TRAP染色检测提示有多核破骨细胞生成。TNF-α处理组V-ATP酶mRNA表达水平显著高于对照组(P<0.001);TNF-α抗体处理组V-ATP酶mRNA表达水平显著低于对照组(P<0.001)。同时,TNF-α处理组V-ATP酶蛋白表达水平显著高于对照组(P<0.05);TNF-α抗体处理组V-ATP酶蛋白表达水平显著低于对照组(P<0.05)。结论 TNF-α可提高破骨细胞V-ATP酶的表达;TNF-α抗体可抑制破骨细胞V-ATP酶的表达。上述提示TNF-α可能通过提高破骨细胞V-ATP酶的表达从而增加破骨细胞的骨吸收作用。国家自然科学基金资助项目(81272168);;福建省自然科学基金资助项目(2016J01623

Enhanced vaccine accessibility through innovative regulatory sciences

疫苗储存运输要遵循冷链运输(cold; chain,CC)的要求,这很大程度上限制了疫苗的接种和普及,尤其是在那些贫困偏远地区。为扩大疫苗可及性,世界卫生组织(World Health; Organization,WHO)于2012年首次提出了受控温度链(controlled temperature; chain,CTC)法规,即在政府部门和WHO的监管下,在有充分热稳定性数据支持的前提下,若申报CTC的疫苗在不低于40 ℃下存放至少3; d后仍能保证效力,则该疫苗在免疫供应链后期无需冷链运输。CTC法规已成功应用在包括MenAfriVac~在内的4个商品化疫苗上。本文介绍了CTC; 法规的内容和应用情况,通过科学监管提高疫苗可及性,减少不必要的浪费。The need to keep vaccine in a traditional cold chain (CC) is a; constraining factor for many immunization campaigns,particularly in the; resource-limited countries. Increased flexibility with an approach newly; introduced in 2012 was implemented with meningitis a; vaccine,MenAfriVac~,across sub-Saharan Africa,after thorough review of; the scientific data by regulatory authorities and World Health; Organization (WHO). This approach was termedcontrolled temperature; chain(CTC) by allowing the vaccines to be exposed at temperatures of up; to 40 ℃ for a minimum of three days prior to the administration of the; vaccine. There are four vaccines were licensed for CTC,including; MenAfriVac~. This article introduces the details and the applications of; CTC. More efforts are underway to fully realize the potentials of the; CTC strategy for increased vaccine accessibility and reduced wastage

Investigation of Porous Silicon/Carbon Composite as Anodes for Lithium Ion Batteries

以商业化多晶硅粉为原料,采用金属银催化剂诱导化学腐蚀的方法制得三维多孔硅材料。通过优化腐蚀条件,得到孔径约为130 nM,比表面为4.85 M2/g的多孔硅材料。将多孔硅和PAn溶液混合球磨并经高温烧结后在多孔硅表面包覆上一层致密的无定形碳膜,从而制得多孔硅/碳复合材料作为锂离子电池的负极材料。3d多孔硅结构可以缓解电化学嵌/脱锂过程中材料的体积效应,无定形碳膜层可有效改善复合材料的导电性能。电化学性能测试表明,该多孔硅/碳复合负极材料电池在0.4 A/g的恒电流下,首次放电容量3345 M AH/g,首次循环库伦效率85.8%,循环55次后容量仍保持有1645 M AH/g。并且在4 A/g的倍率下,容量仍维持有1174 M AH/g。该方法原料成本低廉,可规模化生产。3D porous silicon was synthesized by metal-assisted chemical etching process using commercially available polycrystalline silicon powders.After chemical etching in optimized solution, 3D porous silicon structures with pore size of about 130 nm and specific surface area of about 4.85 m2/g was obtained.Subsequently, the 3D porous silicon powders treated with ball milling and heat carbonization processes were coated with amorphous carbon and utilized as the anode electrode material for lithium ion battery.The combination of the 3D porous structure and a carbon coating layer can accommodate large mechanical strains by providing the empty space of the pores to alleviate the volume change, and by increasing the electrical conductivity with the carbon layer.The electrodes achieve an initial charge capacity of 3345 m Ah/g with coulombic efficiency of 85.8% as well as a high reversible capacity of 1645 m Ah/g after 55 cycles at 0.4 A/g.And it is capable to retain a capacity of 1174 m Ah/g even at 4 A/g.Thus, this work introduces a novel and easy potential industrial method for fabrication Si/C materials for high-performance lithium ion battery.国家自然科学基金(61176050;21233004)~

Simple Combustion Production and Characterization of Octahydro[60]fullerene with a Non-IPR C-60 Cage

1. Xiamen Univ, State Key Lab Phys Chem Solid Surface, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 3. Xiamen Univ, Sch Life Sci, Xiamen 361005, Peoples R ChinaFor the first time an easier, operable combustion method is employed for the synthesis of non-IPR fullerene, and an octahydro[60)fullerene with a non-IPA C-60 cage (C-60 isomer C-#1809(60)) produced by combustion is isolated and characterized by MS, UV vis, IR, and NMR spectroscopies in combination with DFT calculations. This finding shows that, in addition to chlorine, hydrogen can be an ample cataloreactant for the production of non-IPR fullerene derivatives under such conditions as arc-burning and diffusion combustion.NSFC 20525103 20673088 20973137 20721001 20423002 21031004 973 projects 2007CB815301 2007CB81530

Carbon arc production of heptagon-containing fullerene[68]

通讯作者地址: Xie, SY (通讯作者),Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 3. Xiamen Univ, Fujian Prov Key Lab Theoret & Computat Chem, Xiamen 361005, Peoples R China 4. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected], [email protected], [email protected] carbon heptagon ring is a key unit responsible for structural defects in sp(2)-hybrized carbon allotropes including fullerenes, carbon nanotubes and graphenes, with consequential influences on their mechanical, electronic and magnetic properties. Previous evidence concerning the existence of heptagons in fullerenes has been obtained only in off-line halogenation experiments through top-down detachment of a C(2) unit from a stable fullerene. Here we report a heptagon-incorporating fullerene C(68), tentatively named as heptafullerene[68], which is captured as C(68)Cl(6) from a carbon arc plasma in situ. The occurrence of heptagons in fullerenes is rationalized by heptagon-related strain relief and temperature-dependent stability. (13)C-labelled experiments and mass/energy conservation equation simulations show that heptafullerene[68] grows together with other fullerenes in a bottom-up fashion in the arc zone. This work extends fullerene research into numerous topologically possible, heptagon-incorporating isomers and provides clues to an understanding of the heptagon-involved growth mechanism and heptagon-dependent properties of fullerenes.NNSF of China 21031004 21021061 20973137 20876127 973 Program 2007CB815300(1,7) 2011CB93590

Combustion Synthesis and Electrochemical Properties of the Small Hydrofullerene C50H10

通讯作者地址: Xie, SY (通讯作者),Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 3. Xiamen Univ, Sch Life Sci, Xiamen 361005, Peoples R China 电子邮件地址: [email protected]; [email protected] hydrofullerene C50H10 is synthesized by low-pressure benzeneoxygen diffusion combustion. The structure of C50H10 is identified through NMR, mass spectrometry, and IR and Raman spectroscopy as a D5h symmetric closed-cage molecule with five pairs of fused pentagons stabilized by ten hydrogen atoms. UV/Vis and fluorescence spectrometric analyses disclose its optical properties as comparable with those of its chloride cousin (C50Cl10). Cyclic and square-wave voltammograms reveal that the first reduction potential of C50H10 is more negative than that of C50Cl10 as well as C60, with implications for the utilization of C50H10 as a promising electron acceptor for photovoltaic applications.973 projects 2011CB935901 NSFC 21031004 21021061 2077310

An Entrant of Smaller Fullerene: C-56 Captured by Chlorines and Aligned in Linear Chains

A smaller fullerene C-56 (#913) is stabilized, isolated, and crystallographically characterized as C56Cl10. The geometric parameters of C56Cl10 imply the otherwise unstable cage of C-56 can be stabilized by chlorination through releasing its surface strains and maintaining fragmental aromaticity. An unexpected C Cl center dot center dot center dot Cl C short contact, as well as the linear alignment with pearl - necklace-shaped, is revealed in C56Cl10 crystal.NSFC,20525103,20531050,20721001,20425312, 20423002 973 Program,2007C13815301

Chlorofullerenes featuring triple sequentially fused pentagons

通讯作者地址: Tan,YZ(通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 电子邮件地址: [email protected], [email protected] triple sequentially fused pentagons (TSFP) motif is one of the basic subunits that could be used for constructing fullerenes, but it violates the isolated pentagon rule (IPR) and has not been found in carbon cages to date. The properties of TSFP-incorporating fullerenes are thus poorly explored both theoretically and experimentally. Reported herein are four chlorinated derivatives of three different fullerene cages, all with the TSFP motif. X-ray crystallographic analyses indicate that the molecular strain inherent to the pentagon adjacency of a TSFP is significantly relieved upon exohedral chlorination, leaving one of the four pentagon fusion sites unsaturated and rendering the present derivatives chiral. This unique reactivity, in stark contrast to that of previously reported non-IPR fullerenes containing double fused pentagons or triple directly fused pentagons, can be rationalized by density functional theory calculations, and are expected to stimulate further studies of these new members of the fullerene family, both theoretically and experimentally.NNSF of China 20525103,20531050,20721001,20423002 20673088 973 Program 2007CB81530

Two I-h-symmetry-breaking C-60 isomers stabilized by chlorination

通讯作者地址: Xie, SY (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] abiding surprise in fullerene science is that I-h-symmetric buckminsterfullerene C-60 (ref. 1) (I-h-C-60 or C-#1,812(60), the nomenclature specified by symmetry or by Fowler's spiral algorithm(2)) remains the sole C-60 species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule(3), which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected(4-7), synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C-2v-and C-s-symmetric C-60 cages. These chlorinated species, (C60Cl8)-C-#1,809(1) and (C60Cl12)-C-#1,804(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C60 isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme(8-11).NNSF of China,20525103 ,20531050 ,20721001 , 20571062 ,20425312 973 Program 2007CB81530