与铁电,弛豫铁电变及畴界有关的内耗和介电损耗

在ＫＤＰ，ＴＧＳ中，Ｔｃ附近分别观不则到两个人耗（Ｑ＾－＾１）和介电损耗（Ｄ）峰，在ＬＮＰＰ中观测到相应的两个内耗峰，Ｐ１峰起源于二级相变的涨落效应，而Ｐ２与畴有关，考虑到Ｔｃ附近序参量以及由之而引起的畴界密度和畴界运动的粘滞系数随温度的著变化，计算了与畴界运动有关的内耗和介电损耗，并和实验结果进行了比较，在弛豫铁电体ＰＭＮ－ＰＴ中，Ｔｃ以下也观测到相应于Ｐ２峰的内耗和介电损耗峰，考虑到畴界运动和     

偏铌酸铅陶瓷低频内耗的研究

用低频倒置扭摆对改性偏铌酸铅铁电陶瓷的内耗进行了研究．在新加工的样品中发现了六个内耗峰,分别位于７０℃（Ｐ_１峰）、 ９０℃（Ｐ_２峰）、２００℃（Ｐ_３峰）、２６０℃（Ｐ_４峰）、４３０℃（Ｐ_５峰）和５１０℃（Ｐ_６峰）处．对引起Ｐ_３、Ｐ_１、Ｐ_２和Ｐ_４峰的物理机制进行了详细探讨．分析结果表明,Ｐ_３峰的本质是一定化的 Ｄｅｂｙｅ弛豫内耗峰。相应的激活能和指前因子分别为１．０１４Ｖ和 ２．４×１０^－１４ｓ．它源于氧空位与畴壁的相互作用． Ｐ_１、 Ｐ_２和 Ｐ_４峰与试样的切割加工密切相关,可归结为点缺陷与位错的交互作用．     

动态力学及介电法研究蓖麻油丙烯酸酯共聚网络悬挂链的弛豫运动

用动态力学（内耗）和介电方法研究了由蓖麻油（ｃａｓｔｏｒｏｉｌ）、甲苯二异氰酸酯（ＴＤＩ）、丙烯酸羟乙酯（ＨＥＭＡ）组成的网络（Ａｉ）和由正己醇取代Ａ网络中部分ＨＥＭＡ组成的网络Ｂｉ（ｉ＝０，１，２，３）两种网络的内耗及介电损耗，内耗峰强度随悬挂链数目增加而升高，证实了网络破坏后形成的悬挂链的运动对内耗及介电损耗峰高有明显的贡献。     

非晶态PdCuSi的内耗和DSC研究

用葛摆测量了ａ－ＰｄＣｕＳｉ合金的内耗－温度曲线，证明在该合金的Ｔｇ和Ｔｘ温度附近有两个内耗峰Ｐ１和Ｐ２．Ｐ２峰是与非晶晶化有关的内耗峰，而Ｐ１峰可能是弛豫型的内耗峰．分析了倒扭摆和Ｃｏｌｌｅｔｔｅ摆的灵敏度，阐述了这两种摆不适用于测量ａ—ＰｄＣｕＳｉ类合金的内耗峰．     

非晶态PdCuSi的内耗和DCS研究

用葛摆测量了ａ－ＰｄＣｕＳｉ合金的内耗－温度曲线，证明在该合金的Ｔｇ和Ｔｘ温度附近有两个内耗峰Ｐ１和Ｐ２．Ｐ２峰是与非晶晶化有关的内耗峰，而Ｐ１峰可能是弛豫型的内耗峰，分析了倒扭摆和Ｃｏｌｌｅｔｔｅ摆的灵敏度，阐述了这责任中摆不适用于测量ａ－ＰｄＣｕＳｉ类合金的内耗峰。     

动态力学及介电法研究蓖麻油丙烯酸酯共聚网络悬挂链的弛…

用动态力学（内耗）和介电方法研究了由蓖麻油、甲苯二异氰酸酯（ＴＤＩ）、丙烯酸羟乙酯（ＨＥＭＡ）组成的网络（Ａｉ）和由正己醇取代Ａ网络中部分ＨＥＭＡ组成的网络Ｂ１（ｉ＝０，１，２，３）两种网络的内耗及介电损耗，内耗峰强度随悬挂链数目增加而升高，证实了网络破坏后形成的悬挂链的运动对内耗及介电损耗峰高有明显的贡献。     

曝光时对DCG中Cr2P3／2XPS谱的影响的研究

通过对不同曝光量的重络酸盐明胶（ＤＣＧ）中的Ｃｒ２Ｐ３／２ＸＰＳ（Ｘ射线光电子能谱）的测定发现，Ｃｒ２Ｐ３／２ＸＰＳ谱随曝光量呈规律性的变化；在０￣１９５ｍＪ／ｃｍ＾２曝光量范围内，它的１／５高密度（ＦＷＦＭ，即：ｔｈｅ ｆｕｌｌ ｗｉｄｔｈ ａｔ ｆｉｆｔｈ ｍａｘｉｍｕｍ）和５７６．４ｅＶ附近的峰的相对强度先随曝光量的增加而减小；相反，它的５７９．４ｅＶ和５７７．４ｅＶ附近的两个峰的相对强度却     

超高压处理HDPE的微硬度及DSC研究

用维氏微硬度测定仪和ＤＳＣ对超高压自理的ＨＤＰＥ进行了研究。发现随着处理压力的增大,ＨＤＰＥ的微硬度ＨＶ）提高,在处理时升高温度（ＴＣ）,更有利于ＨＶ的提高。当Ｐｃ＝４．０ＧＰａ,Ｔｃ＝１８０℃时,ＨＶ达最大值１７８．４ＭＰａ,比处理前的的７２．５ＭＰａ提高了１４６％,ＤＳＣ结果表明,ＨＤＰＥ经超高压处理后,结晶度增大,而且除了在１３２℃出现１个普通的强度较大的融吸热峰外,还在１３４℃处附近出现１     

ATS／PEEK共混物的结晶熔融行为

用ＤＳＣ研究了ＰＥＥＫ和ＡＴＳ／ＰＥＥＫ共混物的结晶熔融行为。ＰＥＥＫ的结晶熔融行为取决于其物理状态、熔融、退火结晶和固相处理条件。ＡＴＳ的加入使ＰＰＳ的冷结晶温度Ｔ∝提高，Ｔｃ和Ｔｍ降低。固相处理引起ＰＥＥＫ无定形区热氧化交联，淬火样品退火结晶后出现双熔融峰，随退火温度提高，高温峰Ｔｍ２基本不变，低温峰Ｔｍ１移向高温，最后与Ｔｍ２重迭成单峰。ＡＴＳ对ＰＥＥＫ的Ｔｍ１影响不大，但使其Ｔｍ２降低。     

淬火温度对聚氯乙烯动态力学性能的影响

研究了非晶聚氯乙烯（ＰＶＣ）在橡胶区的淬火温度对α内耗峰的影响。样品分别在橡胶区三个不同的温度退火，然后在冰水混合物中淬火。退火温度分别为８０℃，在玻璃化转变温度Ｔｇ的附近；９０℃，高于Ｔｇ的温度；以及１３０℃，远高于Ｔｇ的温度，动态力学测量的结果表明，在橡胶区的淬火温度对ＰＶＣ的α内耗峰有显著的影响，同时，物理老化的温度范围并不仅仅局限在α内耗峰的峰温Ｔα以下。     

N-Heterocyclic Olefin Type Ionic Liquid with Innate Soft Lewis-Base Character as an Effective Additive for Hybrid Quasi-2D and 3D Perovskite Solar Cells

In optimizing perovskites with ionic liquid (IL), the comparative study on Lewis acid-base (LAB) and hydrogen-bonding (HB) interactions between IL and perovskite is lacking. Herein, methyl is substituted for hydrogen on 2-position of imidazolium ring of N-heterocyclic carbene (NHC) type IL IdH to weaken HB interactions, and the resulting N-heterocyclic olefin (NHO) type IL IdMe with softer Lewis base character is studied in both hybrid quasi-2D (Q-2D) and 3D perovskites. It is revealed that IdMe participates in constructing high-quality Q-2D perovskite (n = 4) and provides stronger passivation for 3D perovskite compared with IdH. Power conversion efficiency (PCE) of Q-2D PEA₂MA₃Pb₄I₁₃ perovskite solar cells (PVSCs) is boosted to 17.68% from 14.03%. PCE and device stability of 3D PVSCs enhances simultaneously. Both theoretical simulations and experimental results show that LAB interactions between NHO and Pb²⁺ take the primary optimization effects on perovskite. The success of engineering LAB interactions also offers inspiration to develop novel ILs for high-performance PVSCs.     

Effect of first-dimension undersampling on effective peak capacity in comprehensive two-dimensional separations

The objective of this work is to establish a means of correcting the theoretical maximum peak capacity of comprehensive two-dimensional (2D) separations to account for the deleterious effect of undersampling first-dimension peaks. Simulations of comprehensive 2D separations of hundreds of randomly distributed sample constituents were carried out, and 2D statistical overlap theory was used to calculate an effective first-dimension peak width based on the number of observed peaks in the simulated separations. The distinguishing feature of this work is the determination of the effective first-dimension peak width using the number of observed peaks in the entire 2D separation as the defining metric of performance. We find that the ratio of the average effective first-dimension peak width after sampling to its width prior to sampling (defined as ) is a simple function of the ratio of the first-dimension sampling time (t(s)) to the first-dimension peak standard deviation prior to sampling (1sigma): = square root1+0.21(t /(s)(1) sigma(2) This is valid for 2D separations of constituents having either randomly distributed or weakly correlated retention times, over the range of 0.2 on t(s)/1 sigma from this expression is in qualitative agreement with previous work based on the effect of undersampling on the effective width of a single first-dimension peak, but predicts up to 35% more broadening of first-dimension peaks than is predicted by previous models. This simple expression and accurate estimation of the effect of undersampling first-dimension peaks should be very useful in making realistic corrections to theoretical 2D peak capacities, and in guiding the optimization of 2D separations.     

Unexpected Giant Microwave Conductivity in a Nominally Silent BiFeO3 Domain Wall

Nanoelectronic devices based on ferroelectric domain walls (DWs), such as memories, transistors, and rectifiers, have been demonstrated in recent years. Practical high-speed electronics, on the other hand, usually demand operation frequencies in the gigahertz (GHz) regime, where the effect of dipolar oscillation is important. Herein, an unexpected giant GHz conductivity on the order of 10³ S m⁻¹ is observed in certain BiFeO₃ DWs, which is about 100 000 times greater than the carrier-induced direct current (dc) conductivity of the same walls. Surprisingly, the nominal configuration of the DWs precludes the alternating current (ac) conduction under an excitation electric field perpendicular to the surface. Theoretical analysis shows that the inclined DWs are stressed asymmetrically near the film surface, whereas the vertical walls in a control sample are not. The resultant imbalanced polarization profile can then couple to the out-of-plane microwave fields and induce power dissipation, which is confirmed by the phase-field modeling. Since the contributions from mobile-carrier conduction and bound-charge oscillation to the ac conductivity are equivalent in a microwave circuit, the research on local structural dynamics may open a new avenue to implement DW nano-devices for radio-frequency applications.     

Evaluation of poly(3-hexylthiophene)/polymeric insulator interface by charge modulation spectroscopy technique

We have investigated the sub-band gap states behaviors in P3HT MIS diodes and P3HT Schottky diode by the combination of C–V characteristics and the charge modulation spectroscopy (CMS) measurements. Single-layered heat-treated P3HT film sandwiched by ITO and Al electrodes behaves as a dielectric film, whereas it behaves as Schottky diode when oxygen molecules were doped. The thickness of depletion layer at Al/P3HT interface is controlled by external voltage, and there are two peaks at around 1.3 eV and 1.95 eV in CMS curves. On the other hand, P3HT MIS diodes deposited on polymeric gate insulators have three peaks in CMS curves at around 1.3, 1.6 and 1.95 eV respectively in accumulation. The first peak observed was attributed to the optical transition of polarons in isolated (1D) P3HT chain, and it was related to the field effect mobility and conjugation length in lamellae chains. The second peak observed was attributed to the optical transition of delocalized polarons in π-stacked (2D) P3HT chains, and the peak intensity became strong for highly crystallized P3HT film. The third peak was attributed to the deeply trapped charges in amorphous P3HT region, respectively.     

Magneto-elastic interchange in ferromagnetic alloys

The internal friction δ, exchange integral A, magnetocrystalline anisotropic constant K_I and saturation magnetization M_s of Fe–Cr–Al and Fe–Cr–Al–Si alloys annealed at 1373 and 1473 K are measured. The energy density and volume fraction of domain walls (DWs) of these alloys are calculated based on the theories of ferromagnetism and the magnetic parameters measured. The physical process of irreversible movement of 90° DWs is suggested. The results indicate the dissipated elastic energy per unit volume due to the irreversible movements of 90° DWs is equal in value to the energy density of DWs, that is γ_w/δ_w=λ_sE/2. It is an effect of magneto-elastic interchange in ferromagnetic alloys.     

Control of magnetic domain-wall polarization by means of angled Oersted field writing

We propose a method to control the polarization of the magnetic domain walls (DWs) in ferromagnetic nanowires. Two neighboring DWs with antiparallel polarization alignment rather than parallel alignment are found to exhibit better stability with a helical magnetic structure that can be hardly be detangled. To achieve such an antiparallel alignment, two co-planar current lines with an angle to the nanowire are designed, from which the Oersted field creates a domain in between the current lines while keeping the polarization of the DWs beneath the current lines, as confirmed by a micromagnetic calculation for ferromagnetic nanowires with perpendicular magnetic anisotropy.     

Isotope and affinity tags in photoreactive substance P analogues to identify the covalent linkage within the NK-1 receptor by MALDI-TOF analysis

Photoreactive analogues of substance P (biotin sulfone-spacer (amino pentanoic or Gly(3))-Arg-Pro-Lys-Pro-(pBzl)Phe-Gln-Phe-Phe-Gly-Leu-Met(O(2))NH(2)) with or without isotope (deuterium) labeling have been synthesized. Deuteriums were present on (d)-biotin or epibiotin sulfone (D(3)), on the Gly(3) spacer linker (D(6)), or on the Gly in position 9 of SP (D(2)). Therefore, peptide analogues could be either unlabeled or tri-, penta-, or hexadeuterated. Results obtained with the use of these peptide analogues show that (d)-biotin sulfone and epibiotin sulfone are not recognized with the same affinity by streptavidin, with (d)-biotin sulfone displaying better affinity for the protein. Photolabeling of the human NK-1 receptor with a 1:1 molar ratio of nondeuterated and deuterated photoreactive substance P (SP) analogues in position 5, followed by combined digestions, purification, and MALDI-TOF mass spectrometry analysis, made the identification of the domain of the receptor covalently linked by the photoreactive SP analogue easier. Indeed, doublets in mass spectra were specific for the covalent complex whereas single peaks could be attributed to contaminating species. This method is particularly suitable when minute amounts of complex have to be analyzed, as in the case of highly hydrophobic G-protein coupled receptors.     

B2 Fe-Al合金中与空位有关的弛豫

利用内耗方法对空冷B2 Fe-Al合金中原子缺陷的运动特征进行了研究.在210℃(称为P1峰)和410℃(称为P2峰)附近观察到两个与样品热空位浓度密切相关的弛豫型内耗峰.研究表明,P1峰产生于应力作用下双空位(V_(Fe)V_(Al))的重新取向,而P2峰起源于反位置原子与Fe空位之间的相互作用.对于富Fe的B2 Fe-Al合金,P2峰产生于应力作用下三倍体缺陷(2V_(Fe)Fe_(Al))的重新取向;而对于富Al的B2 Fe-Al合金,P2峰则产生于应力诱导下Al反位置原子在Fe空位之间的运动.