ISOLATION AND STRUCTURE ELUCIDATION OF A NOVEL STEROL FROM THE SOUTH CHINA SEA SPONGE DYSIDEA SP.

A novel and unusual sterol with unsaturation in the△^(5(14)) position,5α-cholesta-8(14),24(25)-diene-3β,6α-diol 1,was isolated from the South China Ses sponge Dysidea sp.The structure and relative stereochemistry of 1 was established by spectral analysis and comparison to the spectral data of known sterols.

A Novel Interface-Gate Structure for SOI Power MOSFET to Reduce Specific On-Resistance

A novel silicon-on-insulator （SOI） power metM-oxide-semiconductor field effect transistor with an interface-gate （IG SOI） structure is proposed, in which the trench polysificon gate extends into the buried oxide layer （BOX） at the source side and an IG is formed. Firstly, the IG offers an extra accumulation channel for the carriers. Secondly, the subsidiary depletion effect of the IG results in a higher impurity doping for the drift region. A low specific on-resistance is therefore obtained under the condition of a slightly enhanced breakdown voltage for the IG SOI. The influences of structure parameters on the device performances are investigated. Compared with the conventional trench gate SOI and lateral planar gate SOI, the specific on-resistances of the IG SOI are reduced by 36.66% and 25.32% with the breakdown voltages enhanced by 2.28% and 10.83% at the same SOI layer of 3 μm, BOX of 1 μm, and half-cell pitch of 5.5 μm, respectively.

“Standby” EMT and “immune cell trapping” structure as novel mechanisms for limiting neuronal damage after CNS injury

The central nervous system （CNS） contains the two most important organs, the brain and spinal cord, for the orchestration of the mental and physical activities of life. Because of its importance, the human body has evolved barrier systems to protect CNS tissue from the external environment. This barrier is a membrane composed of tightly apposed cells and is selectively permeable to specific molecules by way of membrane transporters.

A NOVEL SYNTHETIC METHOD AND STRUCTURE OF TETRAKIS(BENZOATE)BIS(TRIPHENYLPHOSPHINE OXIDE)DICOPPER(II).OXIDATIVE ADDITION OF DIBENZOYL ON METALLIC COPPER

Dibenzoyl peroxide undergoes oxidative addition on metallic copper with triphenylphosphine in a mixed solvent(acetone,dichloromethane and trichloromethane),and affords the binuclear copper complex (Cu(C_6H_5COO)_2(OPPh_3))_2.Crystals are monoclinic,space group A_2/a,with cell parameters,a=24.337(3),b=10.566(1),c=21.579(2),β= 93.18(1)°, V=5540(1)~3,Z=4,R=0.042,and Rw=0.044 for 5872 observed reflections. Each copper ion is coordinated by four bridging benzoato ligands and one triphenylphosphine oxide group to form binuclear complexes.

SYNTHESIS AND STRUCTURE OF A NOVEL INFINITE-LAYER COPPER(Ⅱ)COMPLEX BRIDGED BY OXAMIDE AND PYRIMIDINE

The complex polymer[Cu_2(oxap)(pyr)_2]_n(ClO_4)_(2n),where oxap^(2-)stands for N,N' -bis(2—aminopropyl)oxamide,have been synthesized.It crystallizes in monoclinic system, space group P2_1/C,with a=8.721(2),b=8.679(2),c=16.741(2),β=98.59(0),Z=4.The least-square refinement coverged at R=0.054,R_w=0.055 with 1869 unique reflections.The whole structure of the complcx consists of layers of two-dimensional network arraying along a-axis with perchlorate ions interspersed in the gap between layers.Inside the layer. trans-oxamide-bridged copper(Ⅱ)dimers connected by pyrimidine in an asymmetric fashion spread out along be plane to form an infinite two-dimensional network.

Multiple broadband magnetoelectric response in Terfenol-D/PZT structure

In this paper, a novel magnetoelectric（ME） composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe（1 Oe = 79.5775 A·m^（-1）） and the excitation frequency of alternating magnetic field ranging from 1 kHz to 200 kHz. The ME voltage of each PZT layer is detected. According to the measurement results, the phase differences are observed among three channels and the multi-peak phenomenon appears in each channel. Meanwhile, the results show that the ME structure can stay a relatively high ME response within a wide bandwidth.Besides, the hysteretic loops of three PZT layers are observed. When the frequency of alternating current（AC） magnetic field changes, the maximum value of ME coefficient appears in different layers due to the multiple vibration modes of the structure. Moreover, a finite element analysis is performed to evaluate the resonant frequency of the structure, and the theoretical calculating results accord well with the experimental results. The experiment results suggest that the proposed structure may be a good candidate for designing broadband magnetic field sensors.

Effect of temperature on the compressive behavior of carbon fiber composite pyramidal truss cores sandwich panels with reinforced frames

This paper focuses on the effect of temperature on the out-of-plane compressive properties and failure mechanism of carbon fiber/epoxy composite pyramidal truss cores sandwich panels （CF/CPTSP）. CFJCPTSP with novel reinforced frames are manufactured by the water jet cutting and interlocking assembly method in this paper. The theoretical analysis is presented to predict the out-of-plane compressive stiffness and strength of CFJCPTSP at different ambient temperatures. The tests of composite sandwich panels are per- formed throughout the temperature range from -90℃ to 180℃. Good agreement is found between theo- retical predictions and experimental measurements. Experimental results indicate that the low tempera- ture increases the compressive stiffness and strength of CF/CPTSP. However, the high temperature causes the degradation of the compressive stiffness and strength. Meanwhile, the effects of temperature on the failure mode of composite sandwich panels are also observed.

High-Temperature and Low-Frequency Acoustic Energy Absorption by a Novel Porous Metamaterial Structure

In this paper,we propose a novel porous metamaterial structure with an improved acoustic energy absorption performance at high-temperature and in the low-frequency range.In the proposed novel porous metamaterial structure,a porous material matrix containing periodically perforated cylindrical holes arranged in a triangular lattice pattern is applied,and additional interlayers of another porous material are introduced around these perforations.The theoretical model is established by adopting the double porosity theory for the interlayer and the cylindrical hole which form an equivalent inclusion and then applying the homogenization method to the porous metamaterial structure formed by the equivalent inclusion and the porous matrix.The temperature-dependent air and material parameters are considered in the extended theoretical model,which is validated by the finite element results obtained by COMSOL Multiphysics.The acoustic or sound energy absorption performance can be improved remarkably at very low frequencies and high temperature.Furthermore,the underlying acoustic energy absorption mechanism inside the unit-cell is investigated by analyzing the distribution of the time-averaged acoustic power dissipation density and the energy dissipation ratio of each constituent porous material.The results reveal that regardless of the temperature,the acoustic energy is mostly dissipated in the porous material with a lower airflow resistivity,while the acoustic energy dissipated in the porous material with a higher airflow resistivity also becomes considerable in the high-frequency range.The novel porous metamaterial structure proposed in this paper can be efficiently utilized to improve the acoustic energy absorption performance at high temperature.

A novel coupled quantum well structure and its excellent electro-optical properties

A novel InGaAs/InAlAs coupled quantum well structure is proposed for large field-induced refractive index change with low absorption loss. In the case of low applied electric field of 15 kV/cm and low absorption loss （α≤100 cm^-1）, a large field-induced refractive index change （for transverse electric （TE） mode, △n= 0.012; for transverse magnetic （TM） mode, △n = 0.0126） is obtained in the structure at the operation wavelength of 1.55 μm. The value is larger by over one order of magnitude than that in a rectangular quantum well. The result is very attractive for semiconductor optical switching devices.

A novel coupled quantum well structure with large field-induced refractive index change and low absorption loss at 1.55 μm

A novel coupled quantum well structure - quasi-symmetric coupled quantum well （QSCQW） is proposed. In the case of low applied electric field （F = 25 kV/cm） and low absorption loss （a ≈ 100 cm^-1）, a large field-induced refractive index change （for TE mode, △n = 0.0106; for TM mode, △n = 0.0115） is obtained in QSCQW structure at operating wavelength λ = 1550 nm. The value is larger by over one to two order of magnitude compared to that in a rectangular quantum well （RQW） and about 50% larger than that of five-step asymmetric coupled quantum well （FACQW） structure under the above work conditions.

A novel super-broadband travelling-wave modulator with nonperiodic domain inversions and ridge structure

In order to obtain large broadband, a novel travelling-wave modulator with nonperiodic domain inversions and ridge structure is proposed. The composite structure is designed to achieve velocity matching between the optical wave and the microwave, to get a 50 characteristic impedance and to reduce the loss of the microwave electrodes with finite element method (FEM). The calculation results show that the frequency response of the new device is flat up to 350 GHz with interaction length of 1 cm, characteristic impedance of 49 , and microwave refractive index of 2.5.

Crystal structure of full-length human glucagon receptor reveals novel receptor activation mechanisms

Subject Code:C05With the support by the National Natural Science Foundation of China,a team of scientists let by Profs.Wu Beili(吴蓓丽),Wang Mingwei and Jiang Hualiang from Shanghai Institute of Materia Medica,Chinese Academy of Sciences has determined the high-resolution atomic structure of a full-length class B

Structural and Biological Insights into the Hot-Spot Marine Natural Products Reported from 2012 to 2021

Comprehensive Summary The vast marine ecosystem contains a sea of natural products,which are potential model molecules for new drug development.With more than one thousand new structures been discovered each year,the past decade has become the golden time for marine natural product discovery,leading to a valuable but extra-large chemical database.Serving as an epitome of the most promising compounds,which take the ultra-new skeletons and/or excellent bioactivities,this review covers 243 hot-spot marine natural products reported from 2012 to 2021,to abstract some important chemical and/or biological inspirations for marine natural product study and marine drug development in the future.In addition,some general rules regarding to the source organism,structure-specialty,organism-structure specificity,and organism-bioactivity relationship of these outstanding compounds will also be presented.

Hierarchical coupling effect in hollow Ni/NiFe2O4-CNTs microsphere via spray-drying for enhanced oxygen evolution electrocatalysis

Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for nanostructure are complicated,low-efficient and underperform for wide-scale applications.Herein,a novel hierarchical framework of hollow Ni/NiFe2O4-CNTs compositemicrosphere forcibly-assembled by zero-dimensional(OD)Ni/NiFo204 nanoparticle(<16 nm)and one-dimensional(1D)self-supporting CNTs was fabricated successfully.Benefitted from the unique nanostructure,such monohybrids can achieve remarkable oxygen evolution reaction(OER)performance in alkaline media with a low overpotential and superior durability,which exceeds most of the commercial catalysts based on IrO/RuO2 or other non-noble metal nanomaterials.The enhanced OER performance of Ni/NiFe2OA-CNTs composite is mainly ascribed to the increased catalytic activity and the optimized conductivity induced by the effects of strong hierarchical coupling and charge transfers between CNTs and Ni/NiFe204 nanoparticles.These effects are greatly boosted by the polarized heterojunction interfaces confirmed by electron holography.The density functional theory(DFT)calculation indicates the epitaxial Ni further enriches the intrinsic electrons contents of NiFe204 and thus accelerates absorption/desorption kinetics of OER intermediates.This work hereby paves a facile route to construct the hollow composite microsphere with excellent OER electrocatalytic activity based on non-noble metal oxide/CNTs.