Cooperatively assembled liquid crystals enable temperature-controlled Förster resonance energy transfer

Balancing the rigidity of a π-conjugated structure for strong emission and the flexibility of liquid crystals for self-assembly is the key to realizing highly emissive liquid crystals (HELCs). Here we show that (1) integrating organization-induced emission into dual molecular cooperatively-assembled liquid crystals, (2) amplifying mesogens, and (3) elongating the spacer linking the emitter and the mesogen create advanced materials with desired thermal–optical properties. Impressively, assembling the fluorescent acceptor Nile red into its host donor designed according to the aforementioned strategies results in a temperature-controlled Förster resonance energy transfer (FRET) system. Indeed, FRET exhibits strong S-curve dependence as temperature sweeps through the liquid crystal phase transformation. Such thermochromic materials, suitable for dynamic thermo-optical sensing and modulation, are anticipated to unlock new and smart approaches for controlling and directing light in stimuli-responsive devices.

A temperature-sensitive Förster resonance energy transfer system was constructed using a highly emissive liquid crystal co-assembled with Nile red, enabling thermo-optical modulation for controlling and directing light in stimuli-responsive devices.     

Security of decoy states QKD with finite resources against collective attacks

The number of transmitted signals in practical quantum key distribution (QKD) protocol is always finite. We discuss the security of decoy states QKD protocol with finite resources by considering the statistical fluctuation for the yield and error rate of the quantum state in different sources of pulses (signal sources and decoy sources). The number of exchanged quantum signals vs positive key generation rate is given with experiment results.     

Lower bounds for the security of modified coherent-one-way quantum key distribution against one-pulse-attack

Upper bounds for the security of coherent-one-way (COW) quantum key distribution protocols have been analyzed by considering the one-pulse-attack [Branciard C, Gisin N and Scarani V (BGS) New J.Phys. (2008) 10 013031]. However, their security analysis was based on long distance case, and the typical value of the transmission distance is larger than 50 km. Applying the sharp continuity for the von Neumann entropy and some basic inequalities, we provide lower bounds for the security of modified coherent-one-way quantum key distribution protocol against the most general one-pulse-attack by only considering photon number resolved detectors that will be used in the receiver's side. Comparing with BGS's security analysis, our security analysis can be satisfied with arbitrary distance case.     

Hollow nanospheres based on the self-assembly of alginate-graft-poly(ethylene glycol) and α-cyclodextrin

This article studies the self-assembly of alginate-graft-poly(ethylene glycol) (Alg-g-PEG) and α-cyclodextrin (α-CD) in aqueous solution. It was found that they could form hollow spheres because of the formation of coil-rod Alg-g-PEG/α-CD inclusion complexes. In these Alg-g-PEG/α-CD complexes, the α-CDs are stacked along the PEG side chains to form a rod block, and alginate main chains act as a coil block. More rod-like blocks in Alg-g-PEG/α-CD favor the formation of small assemblies. The assemblies of Alg-g-PEG/α-CD show a dependence on concentration, temperature, pH, and salt concentration. At low concentration (below 0.125%) or high temperature (above 32 °C), Alg-g-PEG/α-CD particles were unstable and disrupted. Increasing the salt or decreasing the pH resulted in the aggregation of Alg-g-mPEG/α-CD particles, as detected by the increase in the recorded hydrodynamic diameter (D(h)).     

Synthesis and Crystal Structure of[Cu（dppb）（NO_3）]_2（dppb=1,4-Bis（diphenylphosphino）butane）

The synthesis and molecular structure of a new dinuclear copper(Ⅰ) complex [Cu(dppb)(NO 3)] 2 are reported.The compound crystallizes in the monoclinic system,space group P2 1 /n with a=12.830(3),b=10.899(2),c=19.666 (4),β=104.69(3)°,V=2660.1(9)3,Z=4,D c=1.378 g/cm 3,F(000)=1144,the final R=0.0600 and wR=0.0668 for 2951 observed reflections with I > 2σ(Ⅰ).The complex contains a folded Cu 2 P 4 core structure,with two Cu(Ⅰ) atoms being bridged by a pair of dppb ligands to form a 14-membered Cu 2 P 4 C 8 zigzag ring.The ligand sphere of each metal center is completed by a nitrate anion in a chelating fashion.     

Three new biflavonoids from the branches and leaves of Cephalotaxus oliveri and their antioxidant activity

Three new biflavonoids, named oliveriflavones A-C (1–3), together with two known flavonoids (quercetin (4) and rutin (5)), were isolated from the endangered plant Cephalotaxus oliveri. The chemical structures of these compounds were elucidated by comprehensive spectroscopic methods including NMR, HRESIMS, IR, UV, and CD spectra. Compounds 1–5 were first isolated from the genus Cephalotaxus. All the compounds were tested for their antioxidant activity. Compounds 4 and 5 showed excellent activity with IC₅₀ values of 0.03 ± 0.06 μM and 0.02 ± 0.10 μM, respectively.     

HIGH ENERGY DEUTERON-DEUTERON SCATTERING

The differential cross section of deuteron-deuteron elastic scattering at P_d=5.76 GeV/c is calculated based on the Glauber multiple scattering theory in nucleus-nucleus collision. The theoretical result is compared with the experimental data and the agreement is satisfactory. In addition, the influence of the input amplitude is discussed.     

Antiproton-Nucleus Interaction and Coulomb Effect at High Energies

The Coulomb effect in high energy antiproton-nucleus elastic and inelastic scattering from ¹²C and ¹⁶O is studied in the framework of Glauber multiple scattering theory for five kinetic energies ranged from 0.23 to 1.83 GeV. A microscopic shell-model nuclear wave functions, Woods-Saxon single-particle wave functions, and experimental pN amplitudes are used in the calculations. The results show that the Coulomb effect is of paramount importance for filling up the dips of differential cross sections. We claim that the present result for inelastic scattering of antiproton-¹²C is sufficiently reliable to be a guide for measurements in the very near future. We also believe that antiproton nucleus elastic and inelastic scattering may produce new information on both the nuclear structure and the antinucleon-nucleon interaction, in particular the p-neutron interaction.     

石墨烯的声子热学性质研究

声子是石墨烯导热过程中的主要载体,而声子的弛豫时间又是其中最基本、最重要的物理量.本文采用简正模式分解法研究了石墨烯声子的弛豫时间,并且借此分析了不同声子在导热过程中的贡献.该方法通过平衡分子动力学模拟实现,首先通过模拟得到单个声子的能量自相关函数衰减曲线,并进一步采用拟合和积分两种方法得到单个声子的弛豫时间.然后,研究了弛豫时间与波矢、频率和温度的关系.结果发现,弛豫时间随波矢的变化与对应的色散关系相近,弛豫时间与频率和温度的关系符合理论模型:1/τ=νnTm,其中声学支的n为1.56,而光学支结果较为发散,指数m对于不同声子支结果略有不同.最后,还研究了不同频率声子对导热的贡献,发现低频声子在态密度上占有绝对优势,并且其弛豫时间整体高于高频声子,所以低频声子对导热的贡献占据主导地位.     

Puberunine and puberudine, two new C18-diterpenoid alkaloids from Aconitum barbatum var. puberulum

Two C(18)-diterpenoid alkaloids, puberunine (1) and puberudine (2), together with four other new alkaloids, including the first examples having β-oriented substitution at C-3 and a rare chloro-substituent were isolated from Aconitum barbatum var. puberulum. Their structures were elucidated by spectroscopic methods. Puberunine and puberudine, which possess a unique rearranged E ring and an opened A ring, respectively, represent new subtypes of the C(18)-diterpenoid alkaloids. A plausible biosynthetic pathway of 1 and 2 was proposed.