[en] A high power and alterable frequency axial acceletron is studied in this paper. By adding the middle cavity, the RF at the cathode surface is increased and the current modulation coefficient is enhanced, the first order current modulation coefficient is 140% and the second is 68%. By adjusting the output cavity, in terms of the two-dimensional fully electron-magnetic particle-in-cell (PIC) simulation, the output power of 1.25 GW at 2.2 GHz and 480 MW at 4.4 GHz have been obtained

[en] Radiation of the space charge in a magnetically insulated transmission line oscillator (MILO) is studied. The results are as follows: the gain formula in the linear regime is derived in which the gain function is symmetric with respect to the mismatch of synchronism; the radiation field formula in the saturation regime is also derived, it shows that the radiation power at saturation is approximately proportional to the harmonic current squared. The theoretical results above are partially examined by numerical simulations

[en] Design considerations of a high-power and high-frequency magnetically insulated transmission line oscillator (MILO) are proposed. By adding the end emission from the cathode, the insulated magnetic field is enhanced to reach the Hull cutoff criterion, therefore, the frequency can be increased. In terms of the two-dimensional fully electromagnetic particle-in-cell simulation, an output power of 1.16 GW at C band and 270 MW at X band in a MILO have been obtained

[en] Graphical abstract: The nanocomposites constructed from Zn-based MOFs exhibit low carbon content with super-high rate capability and long cycling life. - Highlights: • Novel ZnO@porous carbon matrix nanocomposites are constructed by pyrolysis of Zn-based MOFs. • The nanocomposites constructed with Zn-based MOFs show low carbon content. • The constructed nanocomposites exhibit high energy density, super-high rate capability and long cycling life. - Abstract: Single-C formic acid-based metal-organic frameworks (MOFs) are used to construct novel ZnO@porous carbon matrix nanocomposites by controlled pyrolysis. In the constructed nanocomposites, the porous carbon matrices act as a confined support to prevent agglomeration of the ZnO nanoparticles and create a rapid electron conductive network. Meanwhile, the well-defined, continuous porous structured MOFs provide a large specific surface area, which increases the contact of electrolyte-electrode and improves the penetration of electrolyte. Especially, the reasonable choice of formic acid-based MOFs construct the low carbon content composite, which contribute to the high energy density and long cycle life. The constructed nanocomposites show stable, ultrahigh rate lithium ion storage properties of 650 mAh g⁻¹ at charge/discharge rate of 1 C even after 200 cycles.

[en] A new compound, Ga₆(OH)₄(HPO₄)₂(PO₄)₅·C₈H₂₈N₅·3H₂O (denoted JGP-L1), with a gallophosphate layer and a Ga/P ratio of 6/7 has been synthesized hydrothermally by using tetraethylenepentamine as template. It is characterized by powder X-ray diffraction (XRD), elemental analysis, inductively coupled plasma, and TGA analysis and structurally determined by single-crystal XRD analysis. JGP-L1 crystallizes in the orthorhombic, space group Pna2₁ (no. 33), with a=16.422(3), b=11.898(2), c=18.730(4) A, V=3659.6(13) A³ and Z=4. The structure of JGP-L1 is built up by alternating of Ga(OH)₂O₄ octahedra, Ga(OH)O₄ trigonal bipyramids and PO₄ (or HPO₄) tetrahedra to form inorganic sheets. It is noteworthy that JGP-L1 was synthesized with extremely low reactant concentration, where the reaction mixture exhibits a H₂O:Ga₂O₃ molar ratio of 2220:1

[en] Two new two–dimensional (2D) dysprosium coordination polymers [Dy(2,4′-bpdc)(DMF)₂(NO₃)]_n (1) and {[Dy(2,4′–bpdc)(1,4-BDC)_0.5(DMF)(H₂O)]·1.5H₂O}_n (2) (2,4′-H₂bpdc=2,4′–biphenyldicarboxylic acid, 1,4-H₂BDC=1,4–benzenedicarboxylic acid, DMF=N,N′-dimethylformamide) were synthesized under solvothermal condition and stucturally characterized by means of single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. Single-crystal X-ray analysis revealed that the two coordination polymers possess two types of 2D layered structures. From the viewpoint of network topology, the structures of 1 and 2 can be simplified as (4,4) network. We discuss the effect of solvents and temperature on luminescence properties. The fluorescence spectra of 1 at room temperature and 77 K in the solid-state are almost the same, except the stronger emission intensities derived from ligand–centered at 77 K. It is because the quenching by O3H oscillators was protected at low temperature. Coordination polymer 2 displays characteristic Dy³⁺ ion yellow–green luminescence under 290 nm excitation in DMSO (dimethyl sulfoxide), CH₃CN, and CH₃OH solvents. The fluorescence intensities of 2 increased in the order of DMSO>CH₃CN>CH₃OH. We also studied the fluorescence lifetimes of 1 and 2, and the results revealed that the lifetime in DMSO solvent at room temperature reached to 9.53 μs. Compared with the dysprosium coordination polymers, coordination polymer 2 presents a longer lifetime. Additionally, we calculate the triplet state T₁ datum from the emission spectrum of the Gd³⁺ coordination polymer and discuss the energy transfer mechanisms. The energy transfer process from the lowest triplet state energy level of 2,4′-H₂bpdc ligand to the ⁴F_9/2 state energy level of Dy³⁺ ion is inefficient for both 1 and 2. The energy transfer process is effective after we introducing the chelating ligand 1,4-H₂BDC to the construct of coordination polymer 2, which is ascribe to 1,4-H₂BDC may participate in the process of energy transfer. -- Highlights: • Two new dysprosium coordination polymers were designed and synthesized. • The energy transfer process from ligands to Dy³⁺ ion could be happen efficiently. • The fluorescence intensities of 2 increased with the increase of solvents polarity

[en] An X-ray diffractometer system with high precisions designed for the Beijing Synchrotron radiation Laboratory is described. This system consists of goniometers with motion precision of 0.001 degree, high rating detector, fast electronics, automatic control and data acquisition system with computer. Some experimental results in the rotation anode X-ray generator are provided as well

[en] A new 3-D fluorogallophosphate Ga₇P₈O₃₂F₄(C₆H₂₀N₄)₂·3H₃O⁺·H₂O (denoted JGP-4) with a Ga/P ratio of 7/8 has been synthesized hydrothermally by using triethylenetetramine as the template. It crystallizes in the tetragonal, space group P4-bar2₁c (no. 114), with a=15.461(2), b=15.461(2), c=9.3233(1) A, V=2228.67(5) A³ and Z=2. This is the first metal phosphate with a M/P ratio of 7/8. The 3-D anionic framework of JGP-4 is built up from the vertex linkage of the 1-D chains and Ga₅P₄ building units, forming a 3-D open-framework with 8-membered and four square 4-membered rings along the c-axis direction

[en] The first measurement results of X-ray spectrum at the beam lines of synchrotron radiation are provided. The detector and spectral system, measuring method and data acquisition are described

[en] A novel donor-acceptor type conjugated polymer PTBFTPD based on two-dimensional (2D) conjugated alkylthienyl substituted thieno[2,3-f]benzofuran (TBF) and thienopyrroledione (TPD) unit, was synthesized and applied as donor material for bulk heterojunction solar cells. The novol polymer possesses a narrow bandgap of 1.83 eV, a deep HOMO energy level (-5.64 eV) and a closer π−π stacking. After conventional devices were fabricated using PTBFTPD as donor blending with PC₇₀BM as acceptor, a power conversion efficiency (PCE) of 4.33% with a high open circuit voltage (V_oc) of 1.09 V was obtained. The result indicates the promising potential of thieno [2, 3-f] benzofuran unit for high efficient polymer solar cells with a high voltage. (paper)