PYX基高聚物粘结炸药界面相互作用及力学性能的分子动力学模拟

本文采用分子动力学(MD)方法,模拟计算了聚氨酯(Estane 5703),三元乙丙橡胶(EPDM),氟聚物(F2311)三种高聚物分子分别与2,6-双(苦氨基)-3,5-二硝基吡啶(PYX)(011)晶面构建的高聚物粘结炸药(PBXs)体系的结合能,内聚能密度,径向分布函数以及力学性能.结果表明,Estane 5703与PYX(011)晶面之间相互作用最强;不同粘结剂与晶体之间的内聚能密度大小顺序为PYX/F2311> PYX/Estane 5703> PYX/EPDM;径向分布函数分析可知PYX(011)晶面与高聚物分子间的相互作用主要为静电相互作用;添加3种粘结剂后PBX体系的拉伸强度和断裂强度都得到了改善,而除了F2311外,加入另外两种粘结剂后,提高了PBX体系的抗剪切应变能力.     

基于近红外光谱两种植物油过氧化值通用模型研究

过氧化值的快速、准确检测对食用油脂的品质及其食品安全控制具有重要意义。近红外光谱技术是一种理想的过氧化值测量手段,但校正模型的建立需要耗费大量的资源。旨在通过近红外光谱信息与油脂过氧化物间的关系分析,探索对不同种类、不同等级植物油建立同一校正模型的可行性,以不同等级的大豆油和菜籽油为研究对象,结合二维相关光谱技术对两种植物油的近红外光谱进行分析,通过间隔偏最小二乘法选择过氧化值通用模型的最佳检测波段,考察了正交信号校正(OSC)、标准正态变量变换(SNV)和二阶导数(SD)对两种植物油过氧化值校正模型的影响,比较了主成分回归(PCR)、偏最小二乘法(PLS)和支持向量机回归(SVR)三种建模方法的预测效果,构建了大豆油(一级+三级)、菜籽油(一级+三级+四级)、一级油(大豆油+菜籽油)、三级油(大豆油+菜籽油)四种通用模型。结果显示:(1)近红外光谱能够检测植物油过氧化值的变化情况,对应的光谱信息主要分布于1 700～2 200 nm区域;(2)通用模型最佳的波段、预处理方法和建模方法分别为1 700～2 200 nm、 SD法和PLS法;(3)四种通用模型中一级植物油(大豆油和菜籽油)的过氧化值通用模型具有较好预测结果,其预测均方根误差(RMSEP)、决定系数(R~2)分别为0.412和0.920,与一级的大豆油和菜籽油单一模型相比,预测精度相差不大。研究表明生产工艺过程相差不大的一级植物油间有可能建立准确性高的通用模型。此外,为了扩展通用模型的性能,需要不断用新产品对模型进行及时更新。     

一组新型络合物晶体结构与光学性能的研究

研究了二氯三烯丙基硫脲合镉(ATCC),二氯三烯丙基硫脲合汞(ATMC)和二溴三烯丙基硫脲合镉(ATCB)三种晶体的结构特点.首次报道了ATMC和ATCB晶体的非线性光学系数及倍频性能;文中分析比较了三种晶体的非线性光学性能;讨论了晶体结构与性能的关系,为探索高效非线性光学新材料提供依据.     

石墨烯片协同氧化铝导热硅脂的制备及其导热性能研究

以石墨烯片和氧化铝(Al_2O_3)粉为导热填料填充到甲基硅油中制备了三种导热硅脂,采用3-ω法测定了所有样品的热导率,结果表明Al_2O_3复合石墨烯片硅脂的热导率达到1.32 W·m~(-1)·K~(-1),明显高于单纯添加石墨烯片和Al_2O_3的导热硅脂的热导率。将这三种导热硅脂装配到电脑中央处理器(CPU)系统中,测试样品的散热性能,发现Al_2O_3复合石墨烯片的导热硅脂具有更好的散热性。实验中选用扫描电子显微镜(SEM)和透射电子显微镜(TEM)测试了材料的形貌。     

衰减全反射红外光谱法快速检测沥青性质的研究

沥青质量的优劣直接影响路用性能和公路寿命。其中蜡含量、软化点和针入度是沥青三大重要指标,其分析过程繁冗耗时。提出了一种快速准确的沥青性质检测方法。实验共收集了220个已依照标准方法JTJ052-2000获得蜡含量、软化点和针入度标准值的沥青样品,采用偏最小二乘法(PLS)建立其红外光谱定量模型,交互验证标准偏差(SECV)分别为0.13,0.88,3.18,预测标准偏差(SEP)分别为0.14,1.06,3.90,小于标准方法的再现性偏差,任意选取不同厂家所生产的3个样品进行重复性测试,均满足标准方法的精密度要求。该方法具有重复性好、分析速度快,操作简单,可显著提高沥青的分析效率,在沥青质量检测与评价领域有着光明的应用前景。     

三指标值法快速筛查不合格植物油

通过测定南方地区常用的花生油、玉米油、菜籽油、大豆油、葵花油、茶籽油、橄榄油等植物油以及地沟油和过期植物油的A3005(代表不饱和度)、A₉₈₅(代表共轭脂肪酸含量)、A₉₆₀+A₉₈₅(代表反式脂肪酸含量)三个指标值,得到了合格植物油三个指标值设定范围。在此基础上,建立快速筛查不合格植物油(过期、添加低价油、添加地沟油)的方法,有效地提高了植物油的监控效率。利用该法筛查出的若干疑不合格油,通过脂肪酸构成法和11, 12, 13, 17脂肪酸含量判定法等,均证实它们是掺杂油或过期油,几种检测方法的结合应用,可进一步推断植物油不合格的原因。     

骨架密实型低噪声路面降噪机理的实验研究

配制了传统的沥青混凝土(AC)、碎石沥青玛蹄脂(SMA)、不同橡胶粉掺量的骨架密实型低噪声路面等3类共5个配比的沥青路面,采用驻波法测量了各类沥青路面的吸声系数。并且分析了橡胶粉掺量对密实型低噪声路面动态模量的影响,得出了结论,即在这些路面中,橡胶粉含量为3%的密实型路面的减振降噪效果最好。     

基于荧光光谱及矩阵分析的植物油鉴别技术

利用FS920荧光光谱仪测量42个油样(包括36个纯植物油样,3个调和油样和3个混合油样)的荧光光谱,并对其数据矩阵(EEMs)进行归一化处理,确定了植物油特征激发波长及矩阵分析模型。综合分析植物油在特定范围内(激发波长为250～550 nm,发射波长为260～750 nm)的等高线光谱图和特征发射谱线图,将植物油划分为三类;将矩阵分析模型应用于纯植物油鉴别,分类正确率100%;为验证矩阵分析的定量判别能力,对三种混合油样进行分析,得到接近实际配比的分析结果;对市售三种调和油样本进行分析,得出调和油以大豆和菜籽油为基底的结论。通过对植物油荧光光谱的图谱特征和其矩阵模型的分析,证实荧光光谱技术和矩阵分析法对植物油进行分析和种类鉴别的有效性。     

荧光光谱及平行因子分析法在植物油鉴别中的应用

利用FS920荧光光谱仪测量市售的八种植物油(大豆油、玉米油、橄榄油、稻米油、花生油、核桃油、葵花籽油和芝麻油)共22个样品的荧光光谱,并对其数据矩阵(EEMs)进行平行因子分析,结合荧光谱分析的直观物质表征和平行因子法对灰色体系的组分识别优势,实现了植物油的种类区分与鉴别。综合分析植物油在特定范围内(激发波长为250～550 nm,发射波长为260～750 nm)的三维荧光光谱和等高线光谱图,给出了各植物油峰位、峰数和峰强等特征信息,确定了植物油各荧光谱峰相应的荧光物质(不饱和脂肪酸类、维生素E及其衍生物、叶绿素及类胡萝卜素);将平行因子模型应用于植物油光谱数据矩阵的分析,确定了平行因子分析模型的因子数及各因子的物质基础(维生素E及其衍生物、亚油酸和亚麻酸、脂肪酸氧化产物、植物油氧化产物)。建立了植物油的4因子激发-发射光谱轮廓图和样品因子投影得分图。通过对植物油荧光光谱的图谱特征和其数据阵平行因子模型的分析,证实荧光光谱技术和平行因子分析法对植物油进行分析和种类鉴别的有效性。     

余热驱动的传热强化吸附制冰机实验研究

以活性炭-甲醇为工质对,搭建单床吸附制冰机。采用某种粘结剂与活性炭混合。制作具有良好传热性能的固化活性炭块。吸附床即由此种炭块和带铜肋片的传热管组成。本文针对渔船制冰工况(冷量温度控制在零下7℃)对制冰机进行了模拟试验。系统的性能参数如下:COP为0.07,SCP为11W/kg活性炭。     

The design of polymers for high density magnetic recording media

Polymers are responsible for a large proportion of audio/video/computer tape characteristics. Several years ago, the polymers used as a binder were selected only empirically without fundamental study. From this standpoint, the authors have systematically investigated the different effects of functional groups of various polymer binders on electromagnetic performance. As a result, it was found that the proper design of polymer binders offers significant potential for further improvement in magnetic performance. With the recent introduction of high dispersion and high durability binders, it has become clear that the particulate media like a metal tape dominates in the field of higher density recording media such as an 8 mm and Hi-8 video tape, a professional video tape like a Beta CAM SP, D2, D3, UNIHI and 1.2 Gb/s HD, and a DAT streamer tape.     

真空净化处理对掺杂烧结型金刚石聚晶耐磨性的影响

 本文对金刚石原料和不同结合剂进行了真空净化处理试验研究。金刚石原料粒度越细，d电子亏损越多的过渡元素做结合剂，通常越需真空净化处理，方能烧结成高耐磨性聚晶金刚石。     

Studies of organic paint binders by NMR spectroscopy

Nuclear magnetic resonance spectroscopy is applied to the study of aged binding media used in paintings, namely linseed oil, egg tempera and an acrylic medium. High resolution 1D and 2D NMR experiments establish the state of hydrolysis and oxidation of the linseed and egg tempera binders after five years of aging, by determining several markers sensitive to the hydrolytic and oxidative processes of the binder lipid fraction. The composition of the acrylic binder co-polymer is determined by 2D NMR spectroscopy, while the identification of a surfactant, poly(ethylene glycol), found in greater amounts in aged acrylic medium, is reported.The non-destructive nature of the proposed analytical NMR methodology, and minimization of the amount of binder material needed through the use of sophisticated cryoprobes and hyphenated LC-NMR techniques, make NMR attractive for the arts analyst, in view of its rapid nature and experimental simplicity. PACS 82.56.Dj; 82.56.Fk; 82.56.Hg; 82.56.Ub     

Multivariate analysis of combined Raman and fibre‐optic reflectance spectra for the identification of binder materials in simulated medieval paints

The non‐invasive identification of paint materials used in works of art is essential, both for preserving and restoring them, and also for understanding and verifying the history surrounding their creation. As such, the development of suitable non‐invasive techniques has received much interest in recent years. We have investigated the use of Fourier transform (FT)‐Raman spectroscopy and fibre‐optic reflectance spectroscopy (FORS), together with multivariate principal‐component analysis (PCA) techniques, in order to identify the pigment and binding materials used in made‐up samples representative of real artwork. We demonstrate that both types of spectroscopy provide complementary information which can be used to identify the pigments and binders in paint samples. We show that PCA with FT‐Raman spectra can be used to assist in the identification of oil‐based binders, and that the additional data provided by FORS spectra enables PCA on combined spectra to identify more complex proteinaceious and polysaccharide‐based binding media. The results presented here demonstrate that multivariate analyses of lead‐based paints, using data measured by FT‐Raman and FORS in conjunction, have much potential for identifying individual pigments and binders in paint samples. This provides a path towards computer‐assisted characterisation of paint materials on artwork. Copyright © 2013 John Wiley & Sons, Ltd.     

The case of the missing delay lines: synthetic delays obtained by cross-channel phase interaction

Temporal models of pitch and harmonic segregation call for delays of up to 30 ms to cover the full range of existence of musical pitch. To date there is little anatomical or physiological evidence for delays that long. We propose a mechanism by which delays may be synthesized from cross-channel phase interaction. Phases of adjacent cochlear filter channels are shifted by an amount proportional to frequency and then combined as a weighted sum to approximate a delay. Synthetic delays may be used by pitch perception models such as autocorrelation, segregation models such as harmonic cancellation, and binaural processing models to explain sensitivity to large interaural delays. The maximum duration of synthetic delays is limited by the duration of the impulse responses of cochlear filters, itself inversely proportional to cochlear filter bandwidth. Maximum delay is thus frequency dependent. This may explain the fact, puzzling for temporal pitch models such as autocorrelation, that pitch is more salient and easy to discriminate for complex tones that contain resolved partials.     

Development and Application of WC-Based Alloys Bonded with Alternative Binder Phase

WC–Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability (the major incentive for alternative binder development), toxicity and properties degeneration. Thus, the current study applies towards summarize the current knowledge of the impacts of different binders partial or total substitution of the traditional cobalt binder highlighting the influences of metal, intermetallic compound, ceramics (metal oxide) binders on the sintering behavior as well as mechanical properties of WC-based alloys, so as to provide reference for those who would like to enhance the performance of cemented carbides with better reliability advancing them to further wide applications and prepare the alloys in a way that is environment friendly, harmless to human health and low in production cost. It is concluded that the alternative for cobalt in tungsten carbide cemented carbide is economically and technically feasible. Strict control of the chemical composition of the binder coupled with taking into careful account the effects of sintering process and subsequent treatments is of great importance to improve the sintering behavior and tailor mechanical properties of tungsten carbide-based hardmetals.     

固体核磁共振技术在水泥基材料研究中的应用

水泥基材料组分、结构复杂,其水化过程、水化产物组成和结构表征是研究中的难点.一维固体核磁共振谱图可定性或定量分析胶凝材料（水泥及矿物掺合料）的水化程度、水化产物（特别是非晶相）的种类和结构,从而揭示胶凝材料的组成、外加剂和环境等因素对水泥基材料水化过程的影响.而二维核磁共振谱可进一步研究不同或同种原子核之间的连接情况,从而明确水化产物中的掺杂、取代,以及有机外加剂在水泥浆体中的分散情况.因此,固体核磁共振技术可获取其它方法难以获得的信息,有力促进水泥水化及其微观结构的研究.     

Influence of binder viscosity on the control of infrared emissivity in low emissivity coating

Low emissivity is the complex system and polymer binder is one of the most important factors that affect optical and mechanical properties of the coating. Low infrared emissivity coatings were prepared by using flake aluminum particles and three types of polymer resins as fillers and binders, respectively. The influence of polymer binder viscosity on pigment particles distribution, surface morphology and infrared emissivity of the coating was systematically investigated. The results indicate that infrared emissivity of the coating can be strongly affected by the resin viscosity at the same preparation condition, which induces different aluminum particles distribution and surface morphology of the coating. Low resin viscosity is helpful for aggregating pigments and reducing the top polymer layer thickness near the surface, thus the infrared emissivity is reduced. If the resin viscosity value is decreased by two orders of magnitude, the infrared emissivity values would be reduced as much as 0.2. Additionally, a theoretical model is proposed to account for this mechanism, which indicates that sedimentation, evaporation and diffusion play important roles in forming different aluminum particles distribution during the drying process of the coating.     

Collagen-based proteinaceous binder-pigment interaction study under UV ageing conditions by MALDI-TOF-MS and principal component analysis

This study focuses on acquiring information on the degradation process of proteinaceous binders due to ultra violet (UV) radiation and possible interactions owing to the presence of historical mineral pigments. With this aim, three different paint model samples were prepared according to medieval recipes, using rabbit glue as proteinaceus binders. One of these model samples contained only the binder, and the other two were prepared by mixing each of the pigments (cinnabar or azurite) with the binder (glue tempera model samples). The model samples were studied by applying Principal Component Analysis (PCA) to their mass spectra obtained with Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS). The complementary use of Fourier Transform Infrared Spectroscopy to study conformational changes of secondary structure of the proteinaceous binder is also proposed. Ageing effects on the model samples after up to 3000?h of UV irradiation were periodically analyzed by the proposed approach. PCA on MS data proved capable of identifying significant changes in the model samples, and the results suggested different aging behavior based on the pigment present. This research represents the first attempt to use this approach (PCA on MALDI-TOF-MS data) in the field of Cultural Heritage and demonstrates the potential benefits in the study of proteinaceous artistic materials for purposes of conservation and restoration.     

Pressure-induced ferroelectric-antiferroelectric phase transitions in lead zirconate-tatanate-based solid solutions

The ferroelectric-antiferroelectric phase transitions induced by hydrostatic pressure in solid solutions based on lead zirconate-titanate (PZT) with introducing 20 at % tin into B sites and composites based on these ceramics have been studied. In the composites with the same composition of solid solution, the transition pressure can be varied within wide ranges depending on the type of binders. The latter is due to the vitrification of the binder and, consequently, the formation of a rigid framework preventing the transmission of pressure to the ceramic matrix.