Mitigating Lattice Distortion of High‑Voltage LiCoO_(2)via Core‑Shell Structure Induced by Cationic Heterogeneous Co‑Doping for Lithium‑Ion Batteries

Inactive elemental doping is commonly used to improve the structural stability of high-voltage layered transition-metal oxide cathodes.However,the one-step co-doping strategy usually results in small grain size since the low diffusivity ions such as Ti^(4+)will be concentrated on grain boundaries,which hinders the grain growth.In order to synthesize large single-crystal layered oxide cathodes,considering the different diffusivities of different dopant ions,we propose a simple two-step multi-element co-doping strategy to fabricate core–shell structured LiCoO_(2)(CS-LCO).In the current work,the high-diffusivity Al^(3+)/Mg^(2+)ions occupy the core of single-crystal grain while the low diffusivity Ti^(4+)ions enrich the shell layer.The Ti^(4+)-enriched shell layer(~12 nm)with Co/Ti substitution and stronger Ti–O bond gives rise to less oxygen ligand holes.In-situ XRD demonstrates the constrained contraction of c-axis lattice parameter and mitigated structural distortion.Under a high upper cut-off voltage of 4.6 V,the single-crystal CS-LCO maintains a reversible capacity of 159.8 mAh g^(−1)with a good retention of~89%after 300 cycles,and reaches a high specific capacity of 163.8 mAh g^(−1)at 5C.The proposed strategy can be extended to other pairs of low-(Zr^(4+),Ta^(5+),and W6+,etc.)and high-diffusivity cations(Zn^(2+),Ni^(2+),and Fe^(3+),etc.)for rational design of advanced layered oxide core–shell structured cathodes for lithium-ion batteries.

Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air atmosphere.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/mol.The endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high temperatures.The cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating rate.Additionally,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data

We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)satellite.Owing to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan Mountains.The land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper stratosphere.At 40°N/S,the peaks were mainly above the topographic regions during the winter.At 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain waves.Near the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from convection.Our results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic distributions.We found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.

Tailoring local structures of atomically dispersed copper sites for highly selective CO2 electroreduction

Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains challenging.Here,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal precursor.Edge‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm–2 at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus RHE.Computational studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH binding.This research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.

Functionally graded structure of a nitride-strengthened Mg_(2)Si-based hybrid composite

The ex-situ incorporation of the secondary SiC reinforcement,along with the in-situ incorporation of the tertiary and quaternary Mg_(3)N_(2) and Si_(3)N_(4) phases,in the primary matrix of Mg_(2)Si is employed in order to provide ultimate wear resistance based on the laser-irradiation-induced inclusion of N_(2) gas during laser powder bed fusion.This is substantialized based on both the thermal diffusion-and chemical reactionbased metallurgy of the Mg_(2)Si–SiC/nitride hybrid composite.This study also proposes a functional platform for systematically modulating a functionally graded structure and modeling build-direction-dependent architectonics during additive manufacturing.This strategy enables the development of a compositional gradient from the center to the edge of each melt pool of the Mg_(2)Si–SiC/nitride hybrid composite.Consequently,the coefficient of friction of the hybrid composite exhibits a 309.3%decrease to–1.67 compared to–0.54 for the conventional nonreinforced Mg_(2)Si structure,while the tensile strength exhibits a 171.3%increase to 831.5 MPa compared to 485.3 MPa for the conventional structure.This outstanding mechanical behavior is due to the(1)the complementary and synergistic reinforcement effects of the SiC and nitride compounds,each of which possesses an intrinsically high hardness,and(2)the strong adhesion of these compounds to the Mg_(2)Si matrix despite their small sizes and low concentrations.

A hierarchically structured tin-cobalt composite with an enhanced electronic effect for high-performance CO_(2) electroreduction in a wide potential range

Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.

Analyses of Reaction Mechanisms among Different Sulfonation Reagents and m-Diphenylamine and Crystal Structures of the Formed Compounds

In the traditional process, m-phenylenediamine reacts with fuming sulfuric acid at high temperature to get intermediates, and then after dehydration occurs intramolecular rearrangement to get 2,4-diaminobenzenesulfonic acid. Traditional methods need to consume a lot of fuming sulfuric acid or concentrated sulfuric acid, resulting in high industrial large-scale production cost, more waste, and posing a serious environmental pollution risk. In this thesis, three different sulfonation reagents were used for the sulfonation reaction of m-phenylenediamine, and the reaction mechanisms and crystal structures of the three pathways were investigated. The three routes are: 1) one-step synthesis of monosulfonated compound 1 from raw material and sulfur trioxide (SO3);2) rapid reaction of raw material and chlorosulfonic acid to synthesize bisulfonated compound 2;3) direct eutectic crystallization of raw material and ordinary sulfuric acid to obtain compound 3. The crystal structure of the compounds synthesized by three paths was analyzed by X-ray single crystal diffraction, and compound 1 was characterized by NMR, Fourier infrared spectra, UV-visible spectrum and Mass spectrometry. The one-step synthesis of SO3 as a sulfonation reagent has the advantages of mild reaction conditions, simple operation and low cost.

Synergy mechanism of defect engineering in MoS_(2)/FeS_(2)/C heterostructure for high-performance sodium-ion battery

MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Herein,a unique MoS_(2)/FeS_(2)/C heterojunction with abundant defects and hollow structure(MFCHHS)was constructed.The synergy of defect engineering in MoS_(2),FeS_(2),and the carbon layer of MFCHHS with a larger specific surface area provides multiple storage sites of Na^(+)corresponding to the surface-controlled process.The MoS_(2)/FeS_(2)/C heterostructure and rich defects in MoS_(2) and carbon layer lower the Na^(+) diffusion energy barrier.Additionally,the construction of MoS_(2)/FeS_(2) heterojunction promotes electron transfer at the interface,accompanying with excellent conductivity of the carbon layer to facilitate reversible electrochemical reactions.The abundant defects and mismatches at the interface of MoS_(2)/FeS_(2) and MoS_(2)/C heterojunctions could relieve lattice stress and volume change sequentially.As a result,the MFCHHS anode exhibits the high capacity of 613.1 mA h g^(-1)at 0.5 A g^(-1) and 306.1 mA h g^(-1) at 20 A g^(-1).The capacity retention of 85.0%after 1400 cycles at 5.0 A g^(-1) is achieved.The density functional theory(DFT)calculation and in situ transmission electron microscope(TEM),Raman,ex-situ X-ray photon spectroscopy(XPS)studies confirm the low volume change during intercalation/deintercalation process and the efficient Na^(+)storage in the layered structure of MoS_(2) and carbon layer,as well as the defects and heterostructures in MFCHHS.We believe this work could provide an inspiration for constructing heterojunction with abundant defects to foster fast electron and Na^(+) diffusion kinetics,resulting in excellent rate capability and cycling stability.

Inverse-opal structured TiO_(2) regulating electrodeposition behavior to enable stable lithium metal electrodes

Lithium metal anode is almost the ultimate choice for high-energy density rechargeable batteries, but its uneven electrochemical dissolution-deposition characteristics lead to poor cycle stability and lithium dendrites safety problems. The fundamental solution to the problems is to interfere electrodeposition process of lithium metal so that it can be carried out reversibly and stably. In this work, an inverse-opal structured TiO2membrane with a thickness of only ~1 μm is designed to regulate the electrodeposition behavior of lithium metal, in which the ordered channels homogenize mass transfer process, the anatase TiO_(2)walls of the ion channels reduce desolvation barrier of solvated lithium-ions, and the spherical cavities with a diameter of ~300 nm confine migration of the adsorbed lithium atoms during electrocrystallization to diminish overpotential of lithium. These systematic effects cover and essentially change the whole process of electrodeposition of lithium metal and eliminate the possibility of lithium dendrite formation. The as-obtained lithium metal electrode delivers a Coulombic efficiency of 99.86% in the 100th cycle, and maintains a low deposition overpotential of 0.01 V for 800 h.

Binary molten salt in situ synthesis of sandwich-structure hybrids of hollowβ-Mo2C nanotubes and N-doped carbon nanosheets for hydrogen evolution reaction

Focused exploration of earth-abundant and cost-efficient non-noble metal electrocatalysts with superior hydrogen evolution reaction(HER)performance is very important for large-scale and efficient electrolysis of water.Herein,a sandwich composite structure(designed as MS-Mo2C@NCNS)ofβ-Mo2C hollow nanotubes(HNT)and N-doped carbon nanosheets(NCNS)is designed and prepared using a binary NaCl–KCl molten salt(MS)strategy for HER.The temperature-dominant Kirkendall formation mechanism is tentatively proposed for such a three-dimensional hierarchical framework.Due to its attractive structure and componential synergism,MS-Mo2C@NCNS exposes more effective active sites,confers robust structural stability,and shows significant electrocatalytic activity/stability in HER,with a current density of 10 mA cm-2 and an overpotential of only 98 mV in 1 M KOH.Density functional theory calculations point to the synergistic effect of Mo2C HNT and NCNS,leading to enhanced electronic transport and suitable adsorption free energies of H*(ΔGH*)on the surface of electroactive Mo2C.More significantly,the MS-assisted synthetic methodology here provides an enormous perspective for the commercial development of highly active non-noble metal electrocatalysts toward efficient hydrogen evolution.

Probing microstructure of solid-state synthesized LiCoO_(2)with MAS NMR spectroscopy

LiCoO_(2)is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density,good thermal stability,and stable voltage platform.Recent works on LiCoO_(2)have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity.However,an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation.Here we employ highresolution solid-state nuclear magnetic resonance(NMR)spectroscopy to study the local atomic environments in LiCoO_(2)synthesized with three common sintering methods.While one-dimensional 7Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry,both 7Li and 59Co relaxation times are highly dependent on the sintering method.We prove that the two-step sintering method favors the elimination of unreacted Co3O4,thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO_(2)/LGPS/LiIn,which is in accordance with its narrowest 7Li linewidth and the longest 7Li/59Co T1.

Constructing BaTiO_(3)/TiO_(2)@polypyrrole composites with hollow multishelled structure for enhanced electromagnetic wave absorbing properties

BaTiO_(3)/TiO_(2)@polypyrrole(PPy)composites with hollow multishelled structure(HoMS)were constructed to enhance the electromagnetic wave absorbing properties of BaTiO_(3)-based absorbing material.BaTiO_(3)/TiO_(2)HoMSs were prepared by hydrothermal crystallization using TiO_(2)Ho MSs as template.Then,FeCl3 was introduced to initiate the oxidative polymerization of pyrrole monomer,forming BaTiO_(3)/TiO_(2)@PPy HoMSs successfully.The electromagnetic wave absorbing properties of BaTiO_(3)/TiO_(2)HoMSs and BaTiO_(3)/TiO_(2)@PPy Ho MSs with different shell number were investigated using a vector network analyzer.The results indicate that BaTiO_(3)/TiO_(2)@PPy HoMSs exhibit improved microwave absorption compared with BaTiO_(3)/TiO_(2)HoMSs.In particular,tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS has the most excellent absorbing performance.The best reflection loss can reach up to-21.80 dB at 13.34 GHz with a corresponding absorber thickness of only 1.3 mm,and the qualified absorption bandwidth of tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS is up to 4.2 GHz.This work paves a new way for the development of high-performance composite microwave absorbing materials.

Surface plasmon assisted high-performance photodetectors based on hybrid TiO_(2)@GaO_(x)N_(y)-Ag heterostructure

In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visible light detection perfor-mance of the heterojunction device.At 380 nm,the responsivity and detectivity of TiO_(2)@GaO_(x)N_(y)-Ag were 0.94 A/W and 4.79×109 Jones,respectively,and they increased to 2.86 A/W and 7.96×1010 Jones at 580 nm.The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s,respectively.Uniquely,at 580 nm,the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO_(2),Ga_(2)O_(3),and other heterojunctions.The excellent optoelectronic characteristics of the TiO_(2)@GaO_(x)N_(y)-Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱband structure of the metal-semiconductor-metal heterojunction and the plasmon resonance effect of Ag,which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate.It is fur-ther illuminated by finite difference time domain method(FDTD)simulation and photoelectric measurements.The TiO_(2)@GaO_(x)N_(y)-Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communica-tion,imaging,and sensing networks.

Li_(2)O/Na_(2)O对YAS微晶玻璃结构、析晶与力学性能的影响

透明微晶玻璃由于优异的力学性能被广泛应用于电子领域。本文采用熔融法制备了不同质量分数Li_(2)O和Na_(2)O的Y_(2)O_(3)-Al_(2)O_(3)-SiO_(2)(YAS)微晶玻璃,通过Raman、DSC、XRD、FESEM、UV-VIS-NIR等测试方法研究了其结构特征、析晶与力学性能。结果表明:当碱金属氧化物R_(2)O(R=Li,Na)总量保持不变,随着Li_(2)O取代Na_(2)O含量的增加,YAS微晶玻璃的转变温度、软化温度和结晶峰温度逐渐降低,Q^(4)基团对应的含量逐渐减少,说明Li_(2)O作为网络外体使YAS微晶玻璃结构逐步解聚,玻璃的析晶能力逐渐增强。在同一热处理制度下,随着Li_(2)O取代量的增加,YAS微晶玻璃维氏硬度显著提升,而透过率明显下降。在680℃/10 h+750℃/1 h热处理制度下,可以制备出晶体大小一致且分布均匀的以钇稳定氧化锆为主晶相的透明YAS微晶玻璃,此时2%(质量分数,下同)Na_(2)O+4%Li_(2)O YAS微晶玻璃具有良好的综合性能,如维氏硬度为646 HV,断裂韧性为1.07 MPa·m^(1/2),透过率为85.7%,在诸多领域具有巨大的应用潜力。

基于Structure2vec算法的网络欺诈风险特征选择与评估

现有特征选择算法往往只能处理简单的拓扑结构图形,对复杂的拓扑结构图形无能为力,为此选择Structure2vec算法对网络欺诈风险进行研究。在梳理相关文献基础上,对Structure2vec的数学原理进行分析,给出其对应的卷积神经网络模型;选择网络用户的信用历史、身份特质、行为偏好、履约能力和社会关系等5种类型特征数据,构建Stucture2vec关系图;利用Structure2vec算法编写Python程序,对样本数据进行训练,获得模型;利用测试数据对模型进行测试,获得特征向量和对应的风险评估值。结果表明,利用Structure2vec算法对网络欺诈风险进行特征选择和评估,效果优于一般卷积神经网络。

基于哨兵-2数据的白岗岩型铀矿构造蚀变特征研究——以纳米比亚罗辛矿区为例

白岗岩型铀矿是重要的铀矿资源,但针对该类铀矿典型矿床遥感特征的研究还十分薄弱。文章以纳米比亚罗辛铀矿区为研究对象,获取了该矿区哨兵-2遥感影像,总结了矿区典型蚀变矿物的光谱吸收特征,建立了针对矿区地质体的增强与构造解译方法。在此基础上,对获取的遥感影像进行了大气校正与几何校正,并应用主成分分析、波段比值等方法,提取了铁染、羟基和碳酸盐化蚀变信息。结果表明,罗辛铀矿中碳酸盐化蚀变在空间上与卡里毕比组的分布较为一致。通过选取合理的阈值,识别出与铀成矿相关的含大理岩地层。同时,对图像进行增强,并利用建立的构造解译方法,对罗辛铀矿的构造进行了识别。经野外查证,发现遥感识别构造、蚀变与野外查证结果一致,说明利用哨兵-2数据可以对白岗岩型铀矿的成矿条件与控矿要素进行识别,进而为铀矿勘查提供参考。

ZnO/TiO_(2)核-壳纳米结构的低温制备及其光电性能研究

ZnO因其自身的高电荷复合、化学性质活泼,导致其应用受到限制,通过表面修饰进行复合可实现电子-空穴的分离并提高其化学稳定性。以二水合醋酸锌、六水合硝酸锌、六氟钛酸铵为原料,采用溶胶-凝胶、水热和液相沉积相结合的方法,在低温条件下制备出ZnO/TiO_(2)单异质结。采用XRD、SEM、EDS、TEM、PL等对样品进行表征并对其光电性能进行测试。结果表明,在沉积时间为20 min时,ZnO/TiO_(2)核-壳结构形貌最规整,其中ZnO直径约115 nm,TiO_(2)薄膜厚度约7.6 nm;TiO_(2)的负载,降低了电极中光生电荷的复合,提高了ZnO对光子的收集能力,光电流密度提升大约10倍,达到0.21μA/cm^(2),表现出优异的光电化学性能。

核壳结构C-TiO_(2)纳米复合材料用于高效光催化降解有机染料

化工、纺织印染与农药化肥等产业的蓬勃发展推动着人类社会的进步,但同时也给环境治理带来了巨大难题。目前,光催化降解局限于在特定波长下针对单一有机污染物进行降解,然而现实中的情况往往更复杂。因此,开发一种多功能光催化材料用于光催化降解不同有机污染物显得尤为重要。采用一步无模板溶剂热法合成了核壳结构的C-TiO_(2)复合材料前驱体,并在氩气气氛下煅烧得到高结晶度的C-TiO_(2)复合光催化材料。运用SEM、TEM、XRD和TG等表征手段对材料进行表征,结论如下:550℃煅烧时的样品为包含少量碳的高结晶度的锐钛矿相TiO 2,且550℃煅烧时的样品依然保持了完整的核壳结构。此外,C-TiO_(2)复合材料的比表面积高达85.69 m 2·g^(-1),平均孔径为16.4 nm以及孔体积为0.423 m 3·g^(-1)。在UV-Vis光照射下,C-TiO_(2)复合材料分别对罗丹明B(RhB)、亚甲基蓝(MB)和刚果红(CR)3种染料显示出增强的光催化降解活性。

赤眼鳟LGP2序列结构、组织表达及与MDA5互作特征

为探究赤眼鳟遗传学和生理学实验室蛋白2(laboratory of genetics and physiology 2,LGP2)的功能特征及抗草鱼呼肠孤病毒(grass carp reovirus,GCRV)育种参考潜力,实验克隆获得了2940 bp的赤眼鳟lgp2(Sclgp2)全长cDNA和721 bp的5′端上游序列。Sclgp2 cDNA编码680个氨基酸,包含DEXDc(DExD/H-box helicase domain)、HELICc(helicase superfamily C-terminal domain)和CTD(C-terminal regulatory domain)结构域;其5′端上游序列含有MafB(muscle aponeurosis fibromatosis B)和IRF3(interferon regulatory factor 3)等转录因子结合位点。不同物种LGP2的功能结构域、磷酸化修饰位点数具有相似性,同时也存在结构域排布位置及序列的差异。赤眼鳟和草鱼lgp2 cDNA序列比较初步发现2个位于RNA结合功能区的GCRV抗性关联位点。系统进化分析显示,赤眼鳟LGP2先与草鱼、鲫和青鱼聚在一起,再与鲤科鱼类等聚为一大支。荧光定量表达分析显示,赤眼鳟脾脏中sclgp2表达水平显著高于其他组织,肌肉、心脏中表达量次之,而肠中表达量最低。GCRV感染后,肝脏中ifn1表达水平在24~72 h显著下降,其他组织sclgp2和ifn1表达水平未有显著变化。相关性分析结果显示,赤眼鳟肌肉sclgp2与ifn1表达水平呈极显著正相关(0.999)。酵母双杂交互作检测发现,赤眼鳟LGP2与MDA5存在弱相互作用,而其DEXDc(1~201 aa)、HELICc(390~476 aa)以及CTD(553~668 aa)结构域与MDA5无互作。该研究成功获得了sclgp2全长cDNA及5′端上游序列,明确了其序列结构、免疫表达及与MDA5的互作特征,为赤眼鳟LGP2免疫功能属性研究奠定了基础,并为草鱼抗GCRV育种提供了参考。

液态CO_(2)-水循环作用下煤体的物理改性规律及增润减尘效应

煤层注水是预防煤矿粉尘危害的主动性、治本性措施,也是防治瓦斯突出、冲击地压等灾害的重要手段之一。但我国大量煤层具有高地应力、低孔隙率、低渗透性的特点,传统方法和技术面临水注入难、注水周期长、煤体假性润湿等瓶颈。为此,利用液态CO_(2)具有的低温冷冻、高渗透性、相变自增压、酸化解堵等优异特性,提出液态CO_(2)-水循环作用致裂增润煤体的新思路,研制了液态CO_(2)循环冷浸试验系统,联合低场核磁共振仪研究了液态CO_(2)-水循环作用对煤孔隙结构的影响规律,联用电液伺服压力实验机探究了循环作用对煤体力学特性的改变机理,运用截齿破碎煤岩产尘试验系统研究了循环作用后煤体破碎过程的产尘特性。结果表明:液态CO_(2)-水循环作用使煤体有效孔隙度(φ_(NF))增加,增幅与循环作用次数呈正相关,煤体内部束缚流体变少,自由流体增多,T2截止值(T_(2cutoff))随之降低,结合分形理论发现基于渗流孔隙的分形维数Ds具有明显的分形特征,煤体原生孔隙经历了“扩容”的过程,微裂隙与原始裂隙形成贯通,循环作用增强了有效渗流通道连通性,优化了煤的孔隙网络与渗流条件。随着循环次数的增加,煤的最大应力σ_(c)呈指数衰减至4.93 MPa,应变ε_(c)线性增加至2.29×10^(-2),煤的抗压强度减弱,变形能力增加,循环作用改变了煤基质间联结状态,产生的冻胀力对煤体施加挤压作用加剧了裂隙的扩展,脆性指数B5最大降幅为34.71%,显著减弱了煤体脆性,具有了更好的抗动载荷或冲击能力;煤体对外加能量的存储能力弱化,改变了煤在截割过程中的破坏形式,试验条件下煤体破碎过程全尘产尘率降低了74%,呼吸性粉尘占比下降至2%,大幅减弱了粉尘危害性。