HT-7装置液态锂限制器实验中锂的腐蚀与沉积特性的研究

在磁约束聚变等离子体装置中, 面对等离子体的第一壁将直接影响高温等离子体性能及第一壁寿命, 具有表面自我修复的、能有效抑制边界粒子再循环的液态金属锂第一壁越来越被重视, 其中液态锂第一壁与等离子体相互作用的研究尤其重要. 本文研究了HT-7装置液态锂限制器实验中锂的表面腐蚀及在装置内沉积特性、及其对等离子体性能影响. 实验表明, 当锂与等离子体相互作用较弱时, 锂以微弱的蒸发及溅射形式从表面腐蚀并进入等离子体, 表现为锂的线辐射有所增强, 等离子体内杂质水平降低, 氢再循环降低, 有利于等离子体约束性能提高; 当锂与等离子体间的相互作用比较强时, 锂主要以锂滴形式直接进入等离子体, 引起锂的辐射爆发, 最终引发等离子体放电破裂. 通过对锂斑及样品的分析发现, 锂主要沉积在限制器周围, 并且在低场侧及沿着等离子体电流方向沉积居多, 表现为极向和环向分布不均匀, 这也导致边界粒子再循环分布的不均匀. 这些实验为研究液态锂第一壁与等离子体相互作用, 分析液态锂第一壁在托卡马克装置上应用具有重要参考意义.     

“雨课堂”在环境化学教学改革中的应用*

针对环境化学的学科特点和当代人才培养的新要求,尝试将雨课堂的线上和线下教学模式应用到环境化学的教学改革中。实践表明,该模式能够提高学生的学习兴趣和自主性,以及学生分析问题和解决问题的能力,促进师生的课内和课外的交流与互动,充分体现了教学过程中学生的主体地位。     

Determination of Fe(II) and H2O2 in Atmospheric Liquid Water by Peroxyoxalate Chemiluminescence

Abstract

The chemiluminescence reaction of oxygen with bis(2,4,6-trichlorophenyl)oxalate (TCPO) in the presence of Fe(II) has been investigated under the analytical and mechanistic point of view. Its suitability for the determination of Fe(II) as well as H₂O₂ in atmospheric liquid water by using a new static fiberoptic luminometer (FOL) and a flow-injection analysis (FIA) system is demonstrated. Results obtained so far suggest, that chemiluminescence is generated by superoxide ion (O₂ ^?) produced by autoxidation of Fe(II) through dissolved oxygen. The analytical method based on this reaction shows high sensitivity and detection limits below 100 nM Fe(II). Its application to rain water analysis indicates that Fe(II) and H₂O₂ may be coexistent in the atmospheric liquid phase.     

Erosion of multilayered films fabricated from degradable polyamines: Characterization and evidence in support of a mechanism that involves polymer hydrolysis

Multilayered polyelectrolyte assemblies fabricated using hydrolytically degradable polyamines ( 1 – 3 ) erode gradually when incubated in physiologically relevant media. This investigation sought to characterize physically and chemically the erosion of films fabricated from these polymers and sodium poly(styrene sulfonate) (SPS) and to investigate specifically the potential role of polymer hydrolysis in governing film erosion. The characterization of erosion using reflective infrared spectroscopy revealed changes in the carbonyl region of the spectrum that were consistent with the generation of polymer hydrolysis products. To evaluate the role of the esters in these materials more directly, we also synthesized a structural analogue of polymer 2 containing amide functionality rather than ester functionality. Assemblies fabricated from this amide-containing polymer did not erode significantly or release SPS into solution when incubated in phosphate-buffered saline (PBS). Finally, we characterized the erosion of assemblies fabricated from polymer 1 in PBS buffer prepared with D₂O rather than H₂O. These assemblies eroded significantly more slowly in deuterated media than in buffer prepared with H₂O. These results, when combined, provide support for the view that polymer hydrolysis plays an important role in governing the erosion of assemblies fabricated from these degradable polymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5161–5173, 2006     

流化床埋管磨损的实验研究

本文对流化床内埋管的布置与磨损的关系进行了实验研究和理论分析，得到了管束的节距和布置高度对磨损特性的影响规律，并据此提出了埋管的防磨原则。实验表明，只有满足一定的条件，最大的埋管磨损速率才可能出现在底排管上，顺列管束才可能比错列管束磨损轻。     

低硼富含有机质的河/雨水正热电离硼同位素的测定

对低硼富含有机质的河/雨水样品硼的分离方法及硼同位素组成的测定进行了研究.采用硼特效树脂富集河/雨水样品,结合微升华技术去除有机质;采用正热离子质谱法进行硼同位素组成的测定.全流程回收率在97.50%～101.17%之间,测试数据和多接受电感耦合等离子体质谱比较接近,测试精度小于0.05‰.经本方法处理后的样品能满足同...     

时滞位移反馈对Helmholtz振子系统的分形侵蚀安全域的控制

对一个Helmoholtz振子系统引入线性时滞位移反馈,研究时滞位移反馈对系统的安全盆侵蚀的控制作用.将Melnikov函数法推广到时滞系统,从而给出时滞受控系统的安全盆的边界分形条件,在此基础上得出了安全盆分形的激励振幅阈值.再以时滞量为变参数,运用四阶Rung-Kutta方法和点映射方法从定量上研究了时滞对受控系统安全盆的影响规律.结果表明在弱反馈下,时滞量的增大能够提高安全盆边界分形的阈值,进而有效地抑制安全盆的分形侵蚀.说明时滞位移反馈是控制系统的安全盆侵蚀的良好方法. 关键词： 安全盆 分形侵蚀 时滞 反馈     

Study on the Long-Term Acid Rain Aging Behaviour of Polyamide 6

The long-term acid rain aging behavior of polyamide 6 (PA6) was studied in aqueous solution with pH = 1 at 40°C in comparison with a stabilized sample (Stabilizer: 0.2wt% Irganox 1010, 0.2wt% Irgafos 168, 0.3wt% Tinuvin 770 and 0.3wt% Tinuvin 234). The aging can be described as a succession of three stages. The first one corresponded to the physical absorption of water until equilibrium while the chemical degradation can be neglected resulting in a drop of the mechanical strength and an increase of the toughness of the sample of PA6. The hydrolysis reaction of the amido link of PA6 predominated during the middle and last stage of aging, resulting in a decrease of all the mechanical properties. The reduced viscosity of PA6 decreased monotonically during the whole aging process. The end amine group concentration could not be detected due to its reaction with acid. The carboxylic acid came not only from the carboxylic acid end group produced by the degradation of the sample, but also from the acid rain. The stabilizers didn't have any effect of the anti-acid rain degradation of PA6.     

Optimal uncertainty quantification with model uncertainty and legacy data

We present an optimal uncertainty quantification (OUQ) protocol for systems that are characterized by an existing physics-based model and for which only legacy data is available, i.e., no additional experimental testing of the system is possible. Specifically, the OUQ strategy developed in this work consists of using the legacy data to establish, in a probabilistic sense, the level of error of the model, or modeling error, and to subsequently use the validated model as a basis for the determination of probabilities of outcomes. The quantification of modeling uncertainty specifically establishes, to a specified confidence, the probability that the actual response of the system lies within a certain distance of the model. Once the extent of model uncertainty has been established in this manner, the model can be conveniently used to stand in for the actual or empirical response of the system in order to compute probabilities of outcomes. To this end, we resort to the OUQ reduction theorem of Owhadi et al. (2013) in order to reduce the computation of optimal upper and lower bounds on probabilities of outcomes to a finite-dimensional optimization problem. We illustrate the resulting UQ protocol by means of an application concerned with the response to hypervelocity impact of 6061-T6 Aluminum plates by Nylon 6/6 impactors at impact velocities in the range of 5–7 km/s. The ability of the legacy OUQ protocol to process diverse information on the system and its ability to supply rigorous bounds on system performance under realistic—and less than ideal—scenarios demonstrated by the hypervelocity impact application is remarkable.     

Speech endpoint detection in low-SNRs environment based on perception spectrogram structure boundary parameter

The Perception Spectrogram Structure Boundary（PSSB）parameter is proposed for speech endpoint detection as a preprocess of speech or speaker recognition.At first a hearing perception speech enhancement is carried out.Then the two-dimensional enhancement is performed upon the sound spectrogram according to the difference between the determinacy distribution characteristic of speech and the random distribution characteristic of noise.Finally a decision for endpoint was made by the PSSB parameter.Experimental results show that,in a low SNR environment from-10 dB to 10 dB,the algorithm proposed in this paper may achieve higher accuracy than the extant endpoint detection algorithms.The detection accuracy of 75.2%can be reached even in the extremely low SNR at-10 dB.Therefore it is suitable for speech endpoint detection in low-SNRs environment.