全国社会艺术水平考级服务标准化工作介绍

艺术考级源于英国,系指对非艺术专业的人员按一定的要求进行测试以确定其艺术水平和相应等级的做法。改革开放以来,随着人民生活水平的提高和业余艺术教育的逐步普及,一些单位借鉴国外的做法,开始在国内进行考级。     

Recommendation of RILEM TC 260-RSC: using superabsorbent polymers (SAP) to mitigate autogenous shrinkage

This recommendation is devoted to the use of superabsorbent polymers (SAP) in mitigating autogenous shrinkage of concrete and has been prepared by the working group acting within RILEM TC 260-RSC. The recommended procedure for designing mix compositions of concrete with SAP is given. Dry SAP particles of small size should be added to concrete along with additional mixing water that SAP absorb upon mixing. The SAP particles release water during hardening of concrete to compensate for chemical shrinkage and consequently reduce autogenous shrinkage. The procedure for designing mix composition is based on finding a trade-off between mitigation of autogenous shrinkage and possible negative effects on concrete properties (e.g., mechanical properties, workability). A theoretical guideline is provided based on compensating the volume of chemical shrinkage with (additional) internal curing water to be absorbed by the SAP and based on the measured absorption capacity of the SAP.     

Round-robin analysis of the RILEM TC 162-TDF beam-bending test: Part 1—Test method evaluation

A round robin test programme was carried out on the beam-bending test recommended by the RILEM TC 162-TDF [1]. Plain concrete and steel fibre reinforced concrete (SFRC) beams were included in the test programme. The material variables for the SFRC beams consisted of two concrete strengths, three fibre dosages and three types of fibres. A comprehensive statistical analysis was carried out to determine the applicability and robustness of the test method. It was found that although inter-lab variations do occur, this was relatively small compared to the inherent material variation. It is also possible that the high variations observed could be due to the relatively small cross sections used for the test beams. Additionally, an investigation was carried out to evaluate the objectiveness of the calculation procedure proposed by RILEM TC 162-TDF to obtain the necessary design parameters. It was found that the prescribed calculation procedure was satisfactory, as the variation between the design parameters calculated at different laboratories was generally within the range of ±5%. An alternative method of obtaining the design parameters, by considering residual strengths, is suggested as it simplifies the calculation procedure and the test method. In general, the beam test was found to be a good robust test and relatively easy to carry out.     

Recommendation of RILEM TC 238-SCM: determination of the degree of reaction of siliceous fly ash and slag in hydrated cement paste by the selective dissolution method

The performance of slag and fly ash in hydrated cementitious materials depends on the degree of reaction developed at the evaluated age. Several methods for the determination of the reaction degree of supplementary cementitious materials are available, among which the selective dissolution method is one of methods developed the earliest. This is a direct method that aims to quantify the amount of unreacted slag or fly ash in the sample by applying a selective acid attack. The degree of reaction is obtained from the comparison between the remaining unreacted SCM, which should not dissolve, and the total amount initially included in the mix. This recommendation indicates suitable procedures for computing the degree of reaction by selective dissolution of cement pastes containing slag and fly ash. Specific considerations are indicated for necessary corrections due to the imperfect selective dissolution when the procedure is applied to hydrated cement paste.     

Testing superabsorbent polymer (SAP) sorption properties prior to implementation in concrete: results of a RILEM Round-Robin Test

This article presents the results of a round-robin test performed by 13 international research groups in the framework of the activities of the RILEM Technical Committee 260 RSC “Recommendations for use of superabsorbent polymers in concrete construction”. Two commercially available superabsorbent polymers (SAP) with different chemical compositions and gradings were tested in terms of their kinetics of absorption in different media; demineralized water, cement filtrate solution with a particular cement distributed to every participant and a local cement chosen by the participant. Two absorption test methods were considered; the tea-bag method and the filtration method. The absorption capacity was evaluated as a function of time. The results showed correspondence in behaviour of the SAPs among all participants, but also between the two test methods, even though high scatter was observed at early minutes of testing after immersion. The tea-bag method proved to be more practical in terms of time dependent study, whereby the filtration method showed less variation in the absorption capacity after 24 h. However, absorption followed by intrinsic, ion-mediated desorption of a specific SAP sample in the course of time was not detected by the filtration method. This SAP-specific characteristic was only displayed by the tea-bag method. This demonstrates the practical applicability of both test methods, each one having their own strengths and weaknesses at distinct testing times.     

Test method for measuring resistance of industrial floor overlays to impact loading

Durability of industrial floors depends to a great extent on the quality of floor surface, which must be highly resistant to mechanical loads, chemical attack and other types of influence. In order to choose the correct overlay material, it is necessary to define relevant characteristics and use reliable test methods. In this work, the new method is shown developed specifically to test the resistance of industrial floor overlays to impact loading. Compared to other standard test methods, the method suggested here has been adapted to the demands of industrial environments with respect to impact load size, specimen dimensions and shape, as well as boundary conditions. Laboratory tests have been carried out on specimens 40 × 40 × 10 cm and 100 × 100 × 10 cm, and a floor structure with layout dimensions 2.6 × 3.5 m, using different types of overlays.A theoretical model of industrial floor overlay under impact loading has been formulated with the help of the analysis package COSMOS/M, using various parameters such as specimen size and overlay characteristics for the sake of detail evaluation of their particular influence.     

浅谈氢氧火箭发动机液流试验用水技术指标和质量控制

氢氧火箭发动机试验用水水质直接关系到产品试后性能和多余物控制预防.通过对试验用水存在的问题和影响的研究,结合实际运行中的水质化验实测数据,以相关国家标准为依据,分析了试验用水水质关键指标和限定范围并提出了相应的控制监测方法,具有较大的指导意义.     

Laser-induced surface acoustic waves: An alternative method to nanoindentation for the mechanical characterization of porous nanostructured thin film electrode media

The mechanical characterization of electrode materials in thin film lithium ion batteries is currently a sparse area. However, mechanical studies could offer valuable insight since the performance and breakdown of active materials is electromechanically coupled. In this paper, a porous nanostructured V₂O₅ cathode thin film with demonstrated high electrochemical performance was investigated by a laser-induced surface acoustic wave technique (LiSAW) that mitigates some of the challenges associated with the popular nanoindentation technique. The intent was to explore the capability of LiSAW in measuring the elastic modulus of the nanostructured film such that a reliable methodology could be produced to mechanically characterize challenging electrode materials. LiSAW measured a modulus of 53 ± 4 GPa for the porous V₂O₅ film and had no problems coping with the 40 nm roughness and delicate structure. On the other hand, nanoindentation produced a modulus of 50 ± 10 GPa, which is comparable to LiSAW, but with considerably higher uncertainty from roughness. For porous nanostructured electrodes, and other challenging films, that are too soft, thin, or delicate for traditional nanoindentation measurements, LiSAW is a potentially excellent alternative. LiSAW testing on many other electrode materials would be instrumental in developing a better understanding between the mechanical and electrochemical properties of thin film battery materials.     

A review of characterisation methods for superabsorbent polymer (SAP) samples to be used in cement-based construction materials: report of the RILEM TC 260-RSC

Superabsorbent polymers (SAPs) have proven to be a very promising admixture which can positively influence various properties of cement-based materials. SAP samples intended for such use should be pre-tested with respect to their absorptivity as well as their kinetics of ab- and desorption prior to implementation in concrete or mortar. This not only reduces workloads in concrete laboratories in pre-testing modified cement-based mixtures but in fact discloses essentials of the eventual performance of the SAP in concrete and other cementitious materials. The review at hand outlines fundamentals of the thermodynamics of polymer chemistry as a basis for the sorptivity tests. The importance of the ionic composition of the test liquids and the interplay among expansive (swelling) and collapse-causing chemical forces in the hydrogel network are highlighted. Methods of free sorptivity testing in adequate saline solutions as well as absorbency determined subject to the application of external forces are summarised. Advantages and drawbacks of these methods are discussed, including a validation of anticipatory evaluations of SAPs’ performance as admixtures in cement-based building materials. Apart from sorptivity pre-tests several methods of instrumental analytics for the chemical characterisation of SAP samples are drawn up, which represent standard approaches of polymer-chemical analytics.     

Local feedback mode of scanning electrochemical microscopy for electrochemical characterization of one-dimensional nanostructure: theory and experiment with nanoband electrode as model substrate

Local feedback mode is introduced as a novel operation mode of scanning electrochemical microscopy (SECM) for electrochemical characterization of a single one-dimensional (1D) nanostructure, for example, a wire, rod, band, and tube with 1-100-nm width and micrometer to centimeter length. To demonstrate the principle, SECM feedback effects under diffusion limitation were studied theoretically and experimentally with a disk probe brought near a semi-infinitely long band electrode as a geometrical model for a conductive 1D nanostructure. As the band becomes narrower than the disk diameter, the feedback mechanism for tip current enhancement is predicted to change from standard positive feedback mode, to positive local feedback mode, and then to negative local feedback mode. The negative local feedback effect is the only feedback effect that allows observation of a 1D nanostructure without serious limitations due to small lateral dimension, available tip size, or finite electron-transfer rate. In line-scan and approach-curve experiments, an unbiased Pt band electrode with 100-nm width and 2.6-cm length was detectable in negative local feedback mode, even using a 25-microm-diameter disk Pt electrode. Using a 2-microm-diameter probe, both well-defined and defected sites were observed in SECM imaging on the basis of local electrochemical activity of the nanoband electrode. Noncontact and spatially resolved measurement is an advantage of this novel SECM approach over standard electrochemical approaches using electrodes based on 1D nanostructure.     

Simple method for the temporal characterization of amplified spontaneous emission in femtosecond terawatt Ti:sapphire lasers

We have analyzed the temporal characteristics of amplified spontaneous emission (ASE) in femtosecond terawatt Ti:sapphire lasers by using a simple method based on fast photodiodes. Instead of measuring ASE directly with fast photodiodes, we created a narrow gap in the spectrum of seed pulses and, after amplification, detected the pure ASE signal through the gap by using a fast photodiode covered with a bandpass filter with high transmission at the gap. Because the detected ASE signal was completely separated from amplified main pulses, preceding and even trailing ASEs could be characterized quantitatively in a single-shot measurement. We believe that our method is a good alternative or a complement to conventional methods for ASE measurements.     

STEP (Statistical Test of Equivalent Pathways) analysis: a mass spectrometric method for carbohydrates and peptides

We have recently developed a new mass spectrometry method, the STEP (statistical test of equivalent pathways) analysis that uses ion abundances in two tandem mass spectrometry experiments to obtain genealogy information about product ions present in mass spectra. The method requires minimal sample, and it can be performed using a conventional quadrupole ion trap mass spectrometer. To obtain genealogy information, STEP ratios are calculated by comparing the relative abundances of product ions in two MS/MS experiments. These ratios are directly related to the origin of the product ions. Product ions that result directly from the precursor ion always have STEP ratios that are 相似文献   

Correction to: Technical principles of atmospheric carbon dioxide reduction and conversion: economic considerations for some developing countries

Clean Technologies and Environmental Policy -     

3D laser ultramicroscopy: A method for nondestructive characterization of micro- and nanoinclusions in high-purity materials for fiber and power optics

This paper describes a 3D laser ultramicroscopy technique and apparatus for the nondestructive characterization of heterophase inclusions in bulk high-purity materials for fiber and power optics. In this technique, the concentration and size of inclusions undetectable by optical microscopy are determined using CCD detection of the light scattered by them in a direction normal to the incident laser beam at wavelengths from 0.63 to 0.98 μm. The detection limit of the technique in terms of inclusion size is n × (10–100) nm, the range of detectable number concentrations is 1–10¹¹ cm^?3, and the scan depth in the sample is ～1 cm. Its performance has been evaluated using test systems. The potential of the technique is illustrated by the dispersion analysis of promising materials for IR fiber-optic applications.     

Tandem mass spectrometry for structural characterization of proline-rich proteins: application to salivary PRP-3

Proline-rich proteins (PRPs), including collagens, complement 1q, and salivary PRPs, are unusually difficult to sequence by mass spectrometry, due to the high efficiency of cleavage at the amide bond on the N-terminal of proline residues and the consequently low relative abundance of fragment arising from cleavages at other amide bonds. To fully characterize these proteins by mass spectrometry, specialized approaches to fragmentation are needed for the peptides with high proline content. Our work reported herein focused on the analysis of the set of peptides derived by tryptic cleavage of the salivary protein PRP-3. Two methods of fragmentation were compared: Collision-induced dissociation (CID) and electron capture dissociation (ECD). The data obtained demonstrated that ECD spectra of peptides containing more than 30% proline residues are simpler and easier to interpret than are CID spectra of those peptides. Factors that limit the two methods of fragmentation include the complexity of information contained in the CID spectra and the low efficiency of ECD processes. A complementary approach using both decomposition methods provides more complete and interpretable sequence information and yielded >93% sequence coverage for the 11-kDa PRP-3 isolated from human saliva.