The mechanical properties and fracture behavior of a mock polymer bonded explosives (PBX) material were studied using the split Hopkinson pressure bar (SHPB) apparatus. The compressive response of the material is measured from strain rate 110–500 s−1. A dynamic Brazilian test, in which a disc-shaped specimen is loaded diametrically, was chosen to investigate the tensile properties of the material. The fracture behavior of the material was performed on a notched semi-circular bending (SCB) specimen. With a high speed camera and the digital image correlation (DIC) technique, the displacement and strain field history of specimen during loading were observed. The results exhibit that the compressive, tensile and fracture behaviors of the material are all dependency on loading rate, and the DIC technique provides a quantified and non-contact measurement of displacement field and strain field of the specimen under high strain rate loading.

A new 3D noncentrosymmetric mixed-metal sulfate iodate, AgBi(SO4)(IO3)2, has been designed based on a 2D iodate of AgBi(IO3)4via the aliovalent substitution of [IO3]- groups by [SO4]2- groups. Enhancement of the second harmonic generation response (3.0 × KDP to 3.9 × KDP) has been achieved while retaining a favorable NLO framework. This is a novel strategy to upgrade structural dimensions.

通过等价金属离子同位替换的分子设计策略,合成了五个含有重质稀土元素的碘酸钠盐NaRE(IO3)4(RE=Dy,Ho,Er,Yb,Lu),采用单晶衍射技术测定了它们的晶体结构,该系列化合物互为异质同构体,隶属于非中心对称的单斜晶系,Cc空间群.采用紫外-可见吸收光谱、红外光谱、热失重分析、倍频效应测试等手段表征了它们的线性和非线性光学性质及其热稳定性.该系列化合物的二阶非线性光学效应表现出非常明显的差异,倍频效应在0.1 ～3.3×KDP之间且能够相位匹配;它们的光学带隙均大于3.85 eV,热分解温度达到520℃以上.

For upcoming nuclear fusion energy reactors, like the China Fusion Engineering Test Reactor (CFETR) and EUDEMO, the superconducting Cable-In-Conduit Conductors (CICC) are in the design phase, and the operating conditions like electromagnetic forces can be higher than in previous devices like ITER. The prototype conductors for the Central Solenoid (CS) coils in the CFETR, for example, are designed to produce a peak field of 19.9 T and are expected to be made of high current density Nb3Sn strands. Investigations are also ongoing on the application of bismuth strontium calcium copper oxide (BSCCO) and MgB2 strands for CICCs in fusion reactors. The latter material, MgB2, could be applied for superconductors subjected to lower magnetic fields, such as Poloidal Field coils, Correction Coils, and Feeders. The performance of all these strands is sensitive to strain, and the mechanical strength of the brittle filaments is relatively weak. This requires a thorough analysis of the cable pattern in terms of the mechanical support of the strands along their length in combination with the minimization of the interstrand coupling currents and strand indentation. As an initial step to finding the most appropriate cable pattern for CICCs, three prototype CICCs made of ITER type Nb3Sn strands with significantly different cable twist patterns are tested experimentally for AC coupling loss, interstrand contact resistance, and strand indentation. The three cabling patterns referred to as the Twente, CWS (copper wound superconducting strand), and CFETR-CSMC (CFETR Central Solenoid Model Coil) design. The numerical code JackPot ACDC developed at the University of Twente is used to analyze the interstrand coupling loss and contact resistance. The new ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) triplet modified CWS design is aimed at reducing strand pinching during cabling, which causes degradation of transport properties during compaction and cyclic loading. The Twente design has the same objective but also aims at reducing the coupling loss while maximizing the mechanical lateral support for the strands by making the twist pitch ratio of the sequential cabling stages close to one. The CFETR-CSMC, taken as a reference for comparison, has cable a pattern mostly similar to the ITER CS cable design.

Infrared (IR) nonlinear optical (NLO) materials are of current interest owing to their technological applications in many military and civil fields. Metal halides are among the most favorable candidates for IR laser frequency conversion owing to their relatively large NLO effects, wide IR transparency and high laser damage thresholds (LDT). However, the comprehensive review for metal halides NLO materials is absent. Herein, we focus on the relationship between the structural features and NLO performances in the reported metal halide NLO materials. In particular, metal halides are classified according to the NLO-active [MXK] anionic units and NLO-active cations, i.e., they are sorted into traditional metal halides containing linear units, triangle pyramidal units, tetrahedral units, rectangular pyramidal units, five coordinated pseudo-octahedra, six- and more-coordinated polyhedral units, organic-inorganic and supramolecular metal halides. The determination rules of these microscopic structures on NLO properties in metal halides are summarized and analyzed on the basis of the combination of available experimental data and first-principles results. From the deduced structure-property relationship, the development prospects for NLO metal halides are discussed. (C) 2018 Elsevier B.V. All rights reserved.

A series of germanium iodates with a gradual change in polar [IO3]−arrangements have been searched as potential mid-IR nonlinear optical materials.

Boson sampling is a well-defined task that is strongly believed to be intractable for classical computers, but can be efficiently solved by a specific quantum simulator. However, an outstanding problem for large-scale experimental boson sampling is the scalability. Here we report an experiment on boson sampling with photon loss, and demonstrate that boson sampling with a few photons lost can increase the sampling rate. Our experiment uses a quantum-dot-micropillar single-photon source demultiplexed into up to seven input ports of a 16×16 mode ultralow-loss photonic circuit, and we detect three-, four- and fivefold coincidence counts. We implement and validate lossy boson sampling with one and two photons lost, and obtain sampling rates of 187, 13.6, and 0.78 kHz for five-, six-, and seven-photon boson sampling with two photons lost, which is 9.4, 13.9, and 18.0 times faster than the standard boson sampling, respectively. Our experiment shows an approach to significantly enhance the sampling rate of multiphoton boson sampling.

In this work, a series of germanium iodates with different A-site cations A2Ge(IO3)6 (A = Li, K, Rb and Cs) and BaGe(IO3)6·H2O have been synthesized and further explored as potential mid-IR nonlinear optical (NLO) materials. It is found that the change of the alkali metal ionic radius from Li+ to K+–Cs+ greatly affects the coordination environment that alters the arrangement of polar [IO3]− anionic groups, thus leading to the crystal structural shift from the noncentrosymmetric (NCS) structure of P63 for Li2Ge(IO3)6 to the centrosymmetric (CS) structure of R for A2Ge(IO3)6 (A = K, Rb and Cs). The substitution of two alkali ions by one alkali-earth metal ion of Ba2+ with different ionic radius and valence produces another germanium iodate, BaGe(IO3)6·H2O, which contains a crystal water molecule to participate in coordination and crystallizes in another polar space group R3. Li2Ge(IO3)6 and BaGe(IO3)6·H2O with the NCS structure possess second-order NLO properties, in which Li2Ge(IO3)6 shows a very strong second harmonic generation (SHG) response of about 20 × KDP (KH2PO4) under laser irradiation at 1064 nm and 1.95 × KTP (KTiOPO4) under laser irradiation at 1950 nm with type-I phase-matching characteristics, while BaGe(IO3)6·H2O only exhibits a moderate SHG response of 1.5 × KDP with non-phase-matching characteristics. Especially, Li2Ge(IO3)6 shows a large bandgap of 3.60 eV with a laser damage threshold over 12 times that of AgGaS2 under the same measured conditions, and it also shows a relatively wide mid-IR transparent window up to 10 μm and a good crystal growth habit with a high decomposition temperature over 360 °C, suggesting that it will be a promising mid-IR NLO crystal.

Using an ion-substitution strategy, herein, a new polar material, Pb3(SeO3)Br4, with a greatly enhanced SHG response has been successfully designed and synthesized through a hydrothermal reaction. Pb3(SeO3)Br4 crystallizes in the NCS space group P212121 and consists of a three-dimensional framework formed by interconnecting one-dimensional chains, with a good thermal stability up to 230 °C. This compound exhibits a phase-matchable SHG response as strong as that of KH2PO4 (KDP) and a relatively wide mid-infrared (mid-IR) transparent window. Moreover, the optical band gap of Pb3(SeO3)Br4 reaches about 3.35 eV, thus leading to a high laser damage threshold (LDT) of 67 MW cm-2, which is over 12 times that of AgGaS2 (<5 MW cm-2) measured under the same condition. All these findings suggest that Pb3(SeO3)Br4 would be a candidate for an NLO material in the mid-IR region.

Searching for new nonlinear optical (NLO) crystals to be used in the infrared (IR) region is still a challenge. This paper presents the synthesis, crystal structure and properties of a new halide, RbHgI3. Its non-centrosymmetric single crystal can be grown in solution. In its crystal structure, all the polar [HgI4]2− groups align in such a way that brings a favorable net polarization. The measurement by Kurtz–Perry powder technique indicates that RbHgI3 shows a phase-matchable second harmonic generation (SHG) property seven times stronger than that of KH2PO4 (KDP). RbHgI3 displays excellent transparency in the range of 0.48–25 μm with relatively good thermal stability. The UV absorption implies that this yellow compound’s band gap is about 2.56 eV, close to that of AgGaS2. A preliminary measurement indicates that the laser-induced damage threshold of the crystal is about 28.3 MW/cm2. These preliminary experimental data reveal that RbHgI3 is a new candidate as nonlinear optical material in the infrared region.

In this communication, a new series of multibranched second-order nonlinear optical (NLO) chromophores T1-T3 are prepared using triphenylamine moiety as the core to link different number of pentafluorobenzene groups modified chromophores. Upon increasing the number of branched chromophore arms attached to the triphenylamine core, the NLO coefficients (d(33)) can be significantly improved accordingly, due to an integrated effect of enhanced site isolation and Ar-Ar-F self-assembly. As a result, the star-shaped T3 consisting of three-branched chromophore arms realizes an impressive d(33) value, up to 191.8 pm V-1, making it an excellent potential material candidate for second-order NLO applications.

In this paper, BT (( E )-2-(4-(4-(bis(pyridin-2-ylmethyl)amino)styryl)-3-cyano-5,5-dimethylfuran-2(5H)-ylidene)malononitrile) with strong donor–π-acceptor structure was synthesized, which showed both colorimetric and fluorescent sensing ability toward Cu 2+ with high selectivity and sensitivity. Job plot and mass spectra measurement revealed a 1 : 1 coordination mode between Cu 2+ and probe BT in ethanol/HEPES (1 : 4 v/v) buffer (pH 7.2) solution, and the binding constant was calculated to be 3.6 × 10 4 M –1 . The colour of BT solution (10 µM) immediately turned from purple red to yellow and the red fluorescence was quenched obviously when a certain amount of Cu 2+ was added, which enabled a dual-channel detection of Cu 2+ . A paper strip pre-stained with BT solution was further fabricated and it also showed excellent sensing ability toward Cu 2+ with a detection limit as low as 10 −6 M with the naked eye, which represents better portability and operation simplicity that is favourable for on-site analysis of Cu 2+ in water.

A family of nonlinear optical materials that contain the halide, oxide, and oxyhalide polar units simultaneously in a single structure, namely ABi2 (IO3 )2 F5 (A=K (1), Rb (2), and Cs (3)), have been designed and synthesized. They crystallize in the same polar space group (P21 ) with a two-dimensional double-layered framework constructed by [BiF5 ]2- and [BiO2 F4 ]5- units connected to each other by four F atoms, in which two [IO3 ]- groups are linked to [BiO2 F4 ]5- unit on the same side. A hanging Bi-F bond of [BiF5 ]2- unit is located on the other side via ionic interaction with the layer-inserted alkali metal ions to form three-dimensional structure. The well-ordered alignments of these polar units lead to a very strong second-harmonic generation response of 12 (1), 9.5 (2), and 7.5 (3) times larger than that of potassium dihydrogen phosphate under 1064 nm laser radiation. All of them exhibited a wide energy bandgap over 3.75 eV, suggesting that they will have a high laser damage threshold.

对一个含Pb的混合卤化物Pb 7 F 12 Br 2 进行了合成及单晶结构与性能测试,并首次对它的各种与非线性光学材料相关的主要性能进行了研究。发现该化合物的光学带隙宽达4.32 e V,粉末激光损伤阈值为25 MW·cm-2,远高于同等测试条件下商品化红外非线性光学晶体材料AgGaS 2 的粉末激光损伤阈值（＜5.2 MW·cm-2）,它的粉末倍频效应为KDP（KH2PO4）的1.5倍并能够实现相位匹配,粉末透光范围宽为0.3~14μm,热分解温度超过650℃,展示了较好的综合性能。

A family of nonlinear optical materials that contain the halide, oxide and oxyhalide polar units simultaneously in a single structure, namely, ABi2(IO3)2F5 (A = K, 1;Rb,2 and Cs,3), have been designed and synthesized. They crystallize in the same polar space group of P21 with a two-dimensional double-layered framework constructed by [BiF5]2- and [BiO2F4]5- units connected to each other by four F atoms, in which two [IO3]- groups are linked to [BiO2F4]5- unit on the same side, and a hanging Bi-F bond of [BiF5]2- unit is located on the other side via ionic interaction with the layer-inserted alkali metal ions to form three-dimensional structure. The well-ordered alignments of these polar units lead to a very strong second harmonic generation response of 12 (1), 9.5 (2) and 7.5 (3) times larger than that of KDP under 1064 nm laser radiation. All of them exhibited wide bandgap over 3.75 eV, indicating that they will possess high laser damage threshold.

The designed two-photon dye with a β-diketone moiety can undergo a keto-enol equilibrium and thus impart ultrahigh polarity sensitivity. The enol form, as the main component in aprotic environments with a long conjugated chain, displays much stronger two-photon fluorescence, while the keto form in protic environments with negligible fluorescence shows good water-solubility and cell membrane permeability. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

In this work, all-atom molecular dynamics simulations were employed to study the influence of the side alkyl chain on glass transition behavior of several carbazole trimers (CT) in a temperature range from 423 to 183 K. The glass transition temperatures were obtained from the break in the slope of the volume-temperature curves and found to agree with the experimental values. The short time dynamics of four CT molecules were probed by using velocity autocorrelation functions and mean-square displacements. The current studies showed that the dynamics of CT systems can be easily interpreted through the cage effect. Furthermore, the investigation of the torsional autocorrelation function and P2-state/P3-state functions showed that the rotational barriers of side chains can slow down the conformational relaxation and lead to stronger temperature dependence of conformational relaxation. The relaxation time, characteristic time of P2-state(t) and P3-state(t) functions were all found to have Arrhenius-type temperature dependence.

A Pb-containing mixed halide, Pb7F12Br2, was synthesized and confirmed by single X-ray diffraction. Its nonlinear optical (NLO) and related properties have been studied systematically for the first time. It shows much wide energy band gap of 4.32 eV with large laser damage threshold (LDT) value of 25 MW.cm(-2) that is higher than that of the currently commercialized infrared (IR) NLO material AgGaS2 measured at the same conditions (<5.2 MW.cm(-2)). Second harmonic generation (SHG) effect test shows that its powders exhibit phase-matching SHG response of about 1.5 times as strong as that of KDP (KH2PO4). Its powders also show good transparence in the region of 0.3 similar to 44 mu m and exhibit excellent thermal stability with the decomposition temperature up to 650 degrees C. Thus, it shows good comprehensive properties. CCDC: 1559715.

This paper systematically studied the influence of mainchain and sidechain variations on optical, electronic and charge transport properties of polymers.