马协细胞质雄性不育水稻线粒体能量释放特征

测定了马协细胞质雄性不育系及其保持系水稻线粒体能量释放热谱和DSC曲线,探讨了它们在恒温和变温条件下能量释放规律和特性.结果表明马协细胞质雄性不育水稻线粒体在其能量释放过程中放热量较大,能垒较高且机制较为复杂,故其能量释放速率则较其可育系小.     

Electrospinning of carboxymethyl starch/poly(L‐lactide acid) composite nanofiber

Carboxymethyl starch (CMS) is a natural polymer derived from sago starch that is obtained from sago palm (Metroxylon spp.). Herein, CMS was used as a polysaccharide source in preparations of composite nanofibers with poly(L‐lactide acid) (PLLA). The incorporation of CMS with PLLA in nanofiber form has great potential to be used in biomedical applications. The composite PLLA/CMS nanofibers were fabricated by electrospinning technique at various ratios of CMS, which were 5, 10, 15, and 20% vol/vol. The composite nanofibers were characterized according to their physical morphology, chemical interaction, wettability, water uptake, and thermal and mechanical behaviors. The result showed that uniform and bead‐free nanofibers were produced at the low ratio of CMS while fractal and discontinuing fiber was observed at a high ratio of CMS. A better mechanical strength was obtained at low CMS ratio as compared with higher one. Fourier transform infrared results showed that there was an interaction between CMS and PLLA after electrospinning. The surface hydrophilicity and water uptake increased with increasing ratio of CMS. The results from the differential scanning calorimeter analysis showed the decrease of the glass transition (T_g) and cold crystallization temperature (T_cc) of the nanofiber after addition of CMS in PLLA.     

Feasibility study on cross-section measurement ofΥ(1S)→μ~+μ~- by using early CMS data

One of the first physics results that CMS will hopefully obtain will be the analysis of heavy quarkonium productions, including the Υ cross-section measurement. Since the Υ production cross-section from p-p collisions is expected to be relatively large, the analysis should be viable with rather small datasets which will be available soon after the start-up of the LHC. This paper describes the methods and plans for measuring the differential cross-section of Υ(1S) →μ+μ- production, by using data to be collected from the CMS detector in the first LHC run. In this study, about 80 thousand Υ are reconstructed corresponding to an integrated luminosity of 6.4 pb-1 in 10 TeV proton-proton collisions by using Monte Carlo data. The precision of this measurement is estimated to be about 16%, which is limited by the systematic errors.     

Carboxymethylation of corn starch and characterization using asymmetrical flow field-flow fractionation coupled with multiangle light scattering

Asymmetrical flow field-flow fractionation (AsFlFFF) was coupled online with multiangle light scattering (MALS) to study the changes in the molecular weight and the size distribution of the corn starch during carboxymethylation. A corn starch was derivatized with sodium chloroacetate in alcoholic medium under alkaline condition to produce carboxymethyl starches (CMS) having various degrees of substitution (DS). The change in thermal characteristics and granule structure of the native corn starch and CMS were compared using Thermogravimetric analysis and scanning electron microscope. The ionic strength of the carrier liquid (water with 0.02% NaN₃) was optimized by adding 50 mM NaNO₃ to minimize the interactions among the starch molecules and between the starch molecules and the AsFlFFF membrane. A field-programmed AsFlFFF allowed determination of the molecular weight distribution (MWD) of starches within about 25 min. It was found that carboxymethylation of starch results in reduction in the molecular weight due to molecular degradation by the alkaline treatment. The weight-average molecular weight (M_w) was reduced down to about 4.4 × 10⁵ from about 7.2 × 10⁶ when DS was 0.14. It seems AsFlFFF coupled with MALS (AsFlFFF/MALS) is a useful tool for monitoring the changes taking place in the molecular weight and the size of starch during derivatization.     

组合神经网络在结构损伤检测中的应用

子结构的动态响应变化与整体结构相比,对结构内部损伤反应更为敏感。组合神经网络可以克服单个神经网络功能的单一局限性,实现更加全面综合的仿真识别功能。本文首先运用双协调自由界面模态综合法对结构进行模态分析,获取各子结构及整体结构的模态信息。然后,通过组合BP神经网络将损伤子结构与整体结构的模态频率变化率组合起来进行结构损伤检测。该方法在改善网络训练性能的同时,提高了检测结果的准确性和可靠性。文章最后通过数值算例验证了该方法的可行性和有效性。     

Comparative study between a CMS membrane and a CMS adsorbent: Part II. Water vapor adsorption and surface chemistry

The adsorption/desorption equilibria of water vapor in a carbon molecular sieve (CMS) membrane and a commercial CMS adsorbent were determined, exhibiting S-shaped, type V isotherms. The fits of several models found in the literature to the experimental data were evaluated. The results obtained led to the development of a new model accounting for both adsorption and desorption and essentially based on the work of Lagorsse et al. (2005) [15]. Furthermore, the adsorption kinetics was also assessed for both materials and well described by a linear driving force model. The existence of hydrophilic groups responsible for water vapor adsorption in such carbonaceous materials has been related to the surface chemistry by means of X-ray microanalysis and by thermogravimetry. It was concluded from X-ray microanalyses that the carbon membrane presents a lower C/O ratio and is thus more sensitive towards water vapor exposure, as evidenced by the measured water adsorption at lower relative pressures. It was also observed that the diffusion rates are higher for the CMS membrane than for the CMS adsorbent.     

An integrated fuzzy DEA–Fuzzy simulation approach for optimization of operator allocation with learning effects in multi products CMS

This paper presents an integrated fuzzy data envelopment analysis (FDEA) and fuzzy computer simulation approach for optimization of operator allocation in multi product cellular manufacturing systems (CMS) with learning effects. Operator allocation with learning effects is a challenging issue in flexible manufacturing systems in general and in CMS in particular. The main contribution of this work is taking into consideration various operators layouts and learning effects using fuzzy simulation and fuzzy DEA. FDEA is utilized to assess simulation alternatives in various levels of uncertainty. Previous studies consider only one type of product with crisp inputs, whereas this study considers multi-products and fuzzy set up times and processing times for CMS modeling. In addition, this study considers and integrates learning effects for optimum operators’ allocation. Moreover, more robust CMS assessment indicators are used in the proposed model. A case study illustrates the practicability, effectiveness and superiority of the proposed methodology.     

J/ψ→μ+μ- reconstruction in the CMS experiment

In this paper the J/ψ→μ+μ- reconstruction performance in the CMS experiment at the LHC is studied in detail by using B5→ J/ψψ →μμКК events. The reconstruction efficiencies of J/ψ mesons and their decay muons are obtained as a function of the transverse momentum PT and the pseudo-rapidity η. We also study the muon trigger efficiency for this channel with the planned Level-1 trigger and High Level Trigger selection criteria. It was observed that the muon reconstruction efficiency decreases when the two decay muons have a small or large 3D angular separation, which further affects the overall J/ψ reconstruction efficiency.     

Quantification of a Ti(CxN1−x) based multilayer by Auger Electron Spectroscopy

Auger Electron Spectroscopy (AES) is an analytical technique sensitive to the surface of materials and providing elemental and chemical composition of conductive samples. The excellent spatial resolution and its quantification possibilities, even for light elements, make AES a commonly used technique to investigate surface and interfaces.TiN-like materials have a wide range of applications depending on their stoichiometry, but their composition is still complex (or at least not straightforward) to determine because of a strong overlapping of the Ti LMM with the N KLL Auger transitions. This quantification problem can be circumvented using computerised calculations as target factor analysis (TFA) to estimate the different nitrogen and titanium contributions in this peaks overlap. However, a more simple method, based on the study of Ti LMM and Ti LMV area ratio of pure TiN and TiC reference samples, is described in this paper and can be used to obtain the atomic composition of any titanium nitride based compound, whatever the complexity of the material. This method is an alternative to easily quantify TiN-like compounds by AES.As an illustration, a Ti(C_xN_1−x) based multilayer deposited on a hardmetal substrate was investigated. This quantification method was successfully used to evidence three different layers and the diffusion phenomenon at the interfaces between the layers. This study was completed with a quantitative SIMS depth profile that the high sensitivity and depth resolution allowed to measure the small variations of composition lower than the uncertainty of AES.     

Fluoropolymer materials and architectures prepared by controlled radical polymerizations

This review initially summarizes the mechanisms, merits and limitations of the three controlled radical polymerizations: nitroxide mediated polymerization (NMP), atom transfer radical polymerization (ATRP) or metal catalyzed living radical polymerization, and reversible addition-fragmentation chain transfer (RAFT) polymerization. This is followed by two parts, one dealing with homo- and copolymerizations of fluorinated methacrylates and acrylates, and a second where fluorinated styrenes, alone or in combination with other monomers, are the main issues. In these parts, initiators (including multifunctional and macroinitiators), ligands and other reaction conditions as well as some kinetics and conversions are discussed. Numerous possibilities for preparation of a variety of different block copolymers where one or more blocks are fluorinated are devoted particular attention. The advantageous properties and functionalities that can be obtained from these novel fluorinated materials and architectures are especially emphasized. Thus, various amphiphilic, biocompatible or low energy materials, fluorinated nanoparticles and nanoporous films/membranes as well as materials for submicron and nanolevel electronics have been fabricated. In addition, the possible fluorination of various surfaces through surface initiation is highlighted. A final part deals with the use of fluorine containing initiators and macroinitiators, and the applications on the novel materials derived thereof.