基于科学计量学的中国实验力学学科研究水平的国际化比较

本文采用科学计量学方法,对中国实验力学的研究水平进行评估。首先介绍科学计量学方法及评价指标,采用关键词及目标期刊构造相关文献集合;然后对中国实验力学学科的整体产出情况进行国际化比较,并根据中国实验力学学科发展特色,从光测力学、微纳米实验力学、专门化实验力学三个领域分析中国实验力学学科的产出优势及发展趋势,同时给出实验力学相关文献集合的学科分布以及5种重要期刊。结果表明,中国实验力学学科的研究论文产出能力位居全球第二,其影响力水平位居全球第五。     

LC–MS bioanalysis of intact proteins and peptides

Bioanalysis assays that reliably quantify biotherapeutics and biomarkers in biological samples play pivotal roles in drug discovery and development. Liquid chromatography coupled with mass spectrometry (LC–MS), owing to its superior specificity, faster method development and multiplex capability, has evolved as one of the most important platforms for bioanalysis of biotherapeutics, particularly new scaffolds such as half-life extension platforms for proteins and peptides, as well as antibody drug conjugates. Intact LC–MS analysis is orthogonal to bottom-up surrogate peptide approach by providing whole molecule quantitation and high-level sequence and structure information. Here we review the latest development in LC–MS bioanalysis of intact proteins and peptides by summarizing recent publications and discussing the important topics such as the comparison between top-down intact analysis and bottom-up surrogate peptide approach, as well as simultaneous quantitation and catabolite identification. Key bioanalytical issues around intact protein bioanalysis such as sensitivity, data processing strategies, specificity, sample preparation and LC condition are elaborated. For peptides, topics including quantitation of intact peptide vs. digested surrogate peptide, metabolites, sensitivity, LC condition, assay performance, internal standard and sample preparation are discussed.     

A discontinuous Galerkin immersed boundary solver for compressible flows: Adaptive local time stepping for artificial viscosity–based shock-capturing on cut cells

We present a higher-order cut cell immersed boundary method (IBM) for the simulation of high Mach number flows. As a novelty on a cut cell grid, we evaluate an adaptive local time stepping (LTS) scheme in combination with an artificial viscosity–based shock-capturing approach. The cut cell grid is optimized by a nonintrusive cell agglomeration strategy in order to avoid problems with small or ill-shaped cut cells. Our approach is based on a discontinuous Galerkin discretization of the compressible Euler equations, where the immersed boundary is implicitly defined by the zero isocontour of a level set function. In flow configurations with high Mach numbers, a numerical shock-capturing mechanism is crucial in order to prevent unphysical oscillations of the polynomial approximation in the vicinity of shocks. We achieve this by means of a viscous smoothing where the artificial viscosity follows from a modal decay sensor that has been adapted to the IBM. The problem of the severe time step restriction caused by the additional second-order diffusive term and small nonagglomerated cut cells is addressed by using an adaptive LTS algorithm. The robustness, stability, and accuracy of our approach are verified for several common test cases. Moreover, the results show that our approach lowers the computational costs drastically, especially for unsteady IBM problems with complex geometries.     

高速公路PPP项目股权结构、质量水平与VFM的关系研究

高速公路PPP项目属于具有经营收益的准经营性项目,政府制定有效的激励措施,可以鼓励项目公司发挥专业的建设和运营能力,提高项目质量和收益水平。本文以VFM作为政府绩效评价指标,通过构建完全信息静态博弈模型,研究了PPP项目股权结构、质量水平与VFM之间的关系,结果发现:虽然社会资本较多持有项目公司股份有助于提高VFM水平,但随着社会资本方股权比例的增加,项目质量水平在不断降低,所以政府应该将社会资本方的持股比例控制在一定范围内,在保证项目质量的同时达到VFM最大化,从而降低政府方风险,提高社会效益。在高速公路PPP项目中,政府应优化股权决策,激励项目公司改善项目质量和水平,为公私双方带来良好的绩效水平。     

贝利相与非线性输运

电子输运现象包含一系列很重要的材料性质，并可以用来提供关于载体物理系统的很多信息。在 最近的二三十年，人们逐渐认识到除了电子能谱之外，电子在布里渊区的几何性质，比如贝利曲率和 轨道磁矩，会在电子输运中起到关键性的作用。在线性输运现象中的此种关联已引起广泛的兴趣并得 到深入的研究。然而，在非线性输运现象中的电子几何性质的作用的研究最近才逐渐起步。此种关联 可以大大加深对各种非线性输运现象的认识，并对如何从材料控制上调节非线性现象的强度提供有价 值的研究视角和指导原则。基于此背景，本文试图引入研究输运现象的半经典理论框架，并在几种输 运现象中举例说明贝利相的作用。     

New metal complexes derived from S-benzyldithiocarbazate (SBDTC) and chromone-3-carboxaldehyde: synthesis,characterization, antimicrobial,antitumor activity and DFT calculations

Novel monobasic tridentate ONS donor ligand (HL) was synthesized from the condensation reaction of chromone-3-carboxaldehyde with S-benzyldithiocarbazate (SBDTC). Reaction of the ligand with the metal ions copper(II), nickel(II), cobalt(II), oxidovanadium(IV), cerium(III), manganese(II), zinc(II), and cadmium(II) afforded dimeric complexes with the general formula [ML(Y)_m(H₂O)_x]₂·(Y)_m·nH₂O·zCH₃OH, Y?=?NO₃ or Cl, m?=?0–2, x?=?0–2, n?=?0–2, and z?=?0–1 for all complexes except oxidovanadium(IV) complex which has the formula [VOL(H₂O)]₂(SO₄). Structures of the ligand and its metal complexes were established through elemental, spectroscopic data (FT-IR, UV-Vis, and mass), thermal analyses, as well as conductivity and magnetic susceptibility measurements. The geometrical structures of the metal complexes are octahedral and square planar. The ligand and its complexes were subjected to in vitro bioassays against the gram-negative and gram-positive bacteria and the fungus strain with good results for some of these compounds. The antitumor activity of the ligand and its copper(II) and oxidovanadium(IV) complexes were investigated against HepG2 cell line. The molecular parameters of the ligand and its metal complexes have been calculated on the basis of DFT level implemented in the Gaussian 09 program, and computed data were correlated with the experimental results. The HOMO→LUMO electron transition potentially occurs from S-benzyldithiocarbazate to chromone moieties with 4.048?eV. The Mn(II) complex has the highest value of energy barrier, while Cu(II) complex has the lowest value among the complexes. All synthesized complexes have energy gap lower than free ligand and therefore these complexes are more reactive than the free ligand.     

贝利相与非线性输运

电子输运现象包含一系列很重要的材料性质，并可以用来提供关于载体物理系统的很多信息。在 最近的二三十年，人们逐渐认识到除了电子能谱之外，电子在布里渊区的几何性质，比如贝利曲率和 轨道磁矩，会在电子输运中起到关键性的作用。在线性输运现象中的此种关联已引起广泛的兴趣并得 到深入的研究。然而，在非线性输运现象中的电子几何性质的作用的研究最近才逐渐起步。此种关联 可以大大加深对各种非线性输运现象的认识，并对如何从材料控制上调节非线性现象的强度提供有价 值的研究视角和指导原则。基于此背景，本文试图引入研究输运现象的半经典理论框架，并在几种输 运现象中举例说明贝利相的作用。     

Photooptical Properties of Polymethacrylates Having Cyanoazobenzene‐Containing Side Groups with Lateral Methyl Substituents and Different Spacer Length

New photochromic polymethacrylates with different spacer length having azobenzene side groups and lateral methyl substituents were synthesized. The phase behavior of polymethacrylates and their photooptical properties were studied and compared with unsubstituted analogues. It is shown that an introduction of lateral methyl substituents results in almost complete suppression of liquid crystalline (LC) phase formation and strong decrease of photoinduced dichroism values. It is found that rates of the photoinduced E‐Z isomerization and back thermal Z‐E isomerization are almost independent on spacer lengths. Due to the presence of lateral substituents, the photoinduced azobenzene Z‐form shows remarkable long lifetime, and back thermal conversion at room temperature takes more than 10 days. Specific peculiarities of the photoorientation process in polymer films under the polarized UV and visible light action were studied and their mechanism is suggested. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1337–1342     

Tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber

Optical fiber temperature sensors have been widely employed in enormous areas ranging from electric power industry, medical treatment, ocean dynamics to aerospace. Recently, graphene optical fiber temperature sensors attract tremendous attention for their merits of simple structure and direct power detecting ability. However, these sensors based on transfer techniques still have limitations in the relatively low sensitivity or distortion of the transmission characteristics, due to the unsuitable Fermi level of graphene and the destruction of fiber structure, respectively. Here, we propose a tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber (Gr-PCF) with the non-destructive integration of graphene into the holes of PCF. This hybrid structure promises the intact fiber structure and transmission mode, which efficiently enhances the temperature detection ability of graphene. From our simulation, we find that the temperature sensitivity can be electrically tuned over four orders of magnitude and achieve up to ～ 3.34×10^-3 dB/(cm·℃) when the graphene Fermi level is ～ 35 meV higher than half the incident photon energy. Additionally, this sensitivity can be further improved by ～ 10 times through optimizing the PCF structure (such as the fiber hole diameter) to enhance the light-matter interaction. Our results provide a new way for the design of the highly sensitive temperature sensors and broaden applications in all-fiber optoelectronic devices.