Progress on the application of graphene-based composites toward energetic materials:A review

Carbon material is an important additive in energetic materials.Graphene is a monolayer carbon material in which carbon atoms are arranged in two-dimensional honeycomb structure,who has special optical,electrical,and mechanical properties.Recently,the application of graphene-based composites in energetic materials has received extensive attention.This review mainly summarizes the applications of graphene and graphene-based nanomaterials in energetic materials.The effects of these materials on the thermal stability,sensitivity,mechanical property,ignition and combustion of energetic materials were discussed.Furthermore,the progress of functionalized modification of graphene has been summarized,including covalent bonding modification and doping modification.These studies show that graphenebased materials exhibit excellent performances and might emerge as promising candidate for energetic materials.

0D/2D碳氮量子点(CNQDs)/BiOBr复合的S型异质结高效光催化降解和产H_(2)O_(2)

光生载流子的快速复合制约着BiOBr的光催化性能,通过构建界面紧密结合的异质结可以有效地解决这个问题。在本研究中,通过采用简单的高温高压水热法,首次在二维(2D)BiOBr表面上成功复合了零维(0D)的g-C3N4量子点(CNQDs),并形成了具有紧密接触界面的0D/2D CNQDs/BiOBr S型异质结,主要原因是CNQDs杂环中的π电子与BiOBr产生了相互作用。CNQDs/BiOBr-1.50%复合材料在光照下降解四环素(TC)、环丙沙星(CIP)和产H_(2)O_(2)的表观反应速率常数k值分别是BiOBr的2.02、2.91和1.54倍。在循环测试中,CNQDs/BiOBr-1.50%显示出相对较高的光催化活性和结构稳定性。通过X射线光电子能谱(XPS)分析,明确CNQDs中的π电子与BiOBr具有相互作用,确认了异质结中光生电子的转移方向。CNQDs/BiOBrS型异质结的成功构建使其具有非凡的光催化稳定性和活性。更多活性物质的产生和稳定的催化活性归因于电子和空穴的独特转移机制。CNQDs/BiOBrS型异质结的特殊的电子-空穴转移机理实现了载流子在空间的有效分离和转移,且在光照条件下,催化剂上产生了更多的活性自由基,CNQDs/BiOBr复合材料的光催化活性和产H_(2)O_(2)的能力显著增强。这项工作将为构建用于降解有机污染物和原位产H_(2)O_(2)的0D/2D S型异质结提供借鉴与参考。

Accurate design of spatially separated double active site in Bi_(4)NbO_(8)Cl single crystal to promote Z-Scheme photocatalytic overall water splitting

The efficiency of photocatalytic overall water splitting was mainly limited by the slow reaction kinetics of water oxidation.How to design effective surface active site to overcome the slow water oxidation reaction was a major challenge.Here,we propose a strategy to accelerate surface water oxidation through the fabrication spatially separated double active sites.FeCoPi/Bi_(4)NbO_(8)Cl-OVs photocatalyst with spatially separated double active site was prepared by hydrogen reduction photoanode deposition method.Due to the high matching of the spatial loading positions of FeCoPi and OVs with the photogenerated charge distribution of Bi_(4)NbO_(8)Cl and corresponding reaction mechanisms of substrate,the FeCoPi and OVs on the(001)and(010)crystal planes of Bi_(4)NbO_(8)Cl photocatalyst provided surface active site for water oxidation reaction and electron shuttle reaction(Fe^(3+)/Fe^(2+)),respectively.Under visible light irradiation,the evolution O_(2)rate of FeCoPi/Bi_(4)NbO_(8)Cl OVs was 16.8μmol h^(-1),as 32.9 times as Bi_(4)NbO_(8)Cl.Furthermore,a hydrogen evolution co-catalyst PtRu@Cr_(2)O_(3)was prepared by sequential photodeposition method.Due to the introduction of Ru,the Schottky barrier between PbTiO_(3)and Pt was effectively reduced,which promoted the transfer of photogenerated electrons to PtRu@Cr_(2)O_(3)thermodynamically,the evolution H_(2)rate on PtRu@Cr_(2)O_(3)/PbTiO_(3)increased to 664.8 times.On based of the synchronous enhancement of the water oxidation performance on FeCoPi/Bi_(4)NbO_(8)Cl-OVs and water reduction performance on PtRu@Cr_(2)O_(3)/PbTiO_(3),a novel Z-Scheme photocatalytic overall water splitting system(FeCoPi/Bi_(4)NbO_(8)Cl-OVs)mediated by Fe^(3+)/Fe^(2+)had successfully constructed.Under visible light irradiation,the evolution rates of H_(2)and O_(2)were 2.5 and 1.3μmol h^(-1),respectively.This work can provide some reference for the design of active site and the controllable synthesis of OVs spatial position.On the other hand,the hydrogen evolution co catalyst(PtRu@Cr_(2)O_(3))and the co catalyst FeCoPi for oxygen evolution contributed to the construction of an overall water splitting system.

Desulfurization of liquid hydrocarbon fuels via Cu_2O catalyzed photooxidation coupled with liquid–liquid extraction

By combining the photochemical reaction and liquid–liquid extraction(PODS), we studied desulfurization of model fuel and FCC gasoline. The effects of air flow, illumination time, extractants, volume ratios of extractant/fuel, and catalyst amounts on the desulfurization process of PODS were analyzed in detail. Under the conditions with the air as oxidant(150 ml·min^(-1)), the mixture of DMF–water as extractant(the volume ratio of extractant/oil of 0.5) and photo-irradiation time of 2 h, the sulfur removal rate reached only 42.63% and 39.54% for the model and FCC gasoline, respectively. Under the same conditions, the sulfur removal rate increased significantly up to79% for gasoline in the presence of Cu_2O catalyst(2 g·L^(-1)). The results suggest that the PODS combined with a Cu_2O catalyst seems to be a promising alternative for sulfur removal of gasoline.

Research on Key Technologies of Precise InSAR Surveying and Mapping Applications Using Automatic SAR Imaging

Precise interferometric synthetic aperture radar (InSAR) is a new intelligent photogrammetric technology that uses automatic imaging and processing means. Precise InSAR has become the most efficient satellite surveying and mapping (SASM) method that uses the interferometric phase to create a global digital elevation model (DEM) with high precision. In this paper, we propose the application of systematic InSAR technologies to SASM. Three key technologies are proposed: calibration technology, data processing technology and post-processing technology. First, we need to calibrate the geometric and interferometric parameters including the azimuth time delay, range time delay, and atmospheric delay, as well as baseline errors. Second, we use the calibrated parameters to create a precise DEM. One of the important procedures in data processing is the determination of phase ambiguities. Finally, we improve the DEM quality through the joint use of the block adjustment method, long and short baseline combination method and descending and ascending data merge method. We use 6 sets of TanDEM-X data covering Shanxi to conduct the experiment. The root mean square error of the final DEM is 5.07 m in the mountainous regions. In addition, the low coherence area is 0.8 km 2. The result meets the China domestic SASM accuracy standard at both the 1∶50 000 and 1∶25 000 measurement scales.

Macro-superlubricity in sputtered MoS_(2)-based films by decreasing edge pinning effect

To date,MoS_(2) can only be achieved at microscale.Edge pinning effect caused by structure defects is the most obvious barrier to expand the size of structural superlubricity to macroscale.Herein,we plan to pin edge planes of MoS_(2) with nanospheres,and then the incommensurate structure can be formed between adjacent rolling nanoparticles to reduce friction.The sputtered MoS_(2) film was prepared by the physical vapor deposition(PVD)in advance.Then enough Cu_(2)O nanospheres(~40 nm)were generated in situ at the edge plane of MoS_(2) layers by liquid phase synthesis.An incommensurate structure(mismatch angle(θ)=8°)caused by MoS_(2) layers was formed before friction.The friction coefficient of the films(5 N,1,000 r/min)was~6.0×10^(−3) at the most.During friction,MoS_(2) layers pinned on numerous of Cu_(2)O nanoparticles reduced its edge pinning effect and decreased friction.Moreover,much more incommensurate was formed,developing macro-superlubricity.

CLE Peptides in Plants:Proteolytic Processing,Structure-Activity Relationship,and Ligand-Receptor Interaction

Ligand-receptor signaling initiated by the CLAVATA3/ENDOSPERM SURROUNDING REGION （CLE） family peptides is critical in regulating cell division and differentiation in meristematic tissues in plants. Biologically active CLE peptides are released from precursor proteins via proteolytic processing. The mature form of CLE ligands consists of 12-13 amino acids with several post-translational modifications. This review summarizes recent progress toward understanding the proteolytic activities that cleave precursor proteins to release CLE peptides, the molecular structure and function of mature CLE ligands, and interactions between CLE ligands and cor- responding leucine-rich repeat （LRR） receptor-like kinases （RLKs）.

Magnetically Driven Superhydrophobic Polyurethane Sponge for High Efficiency Oil/Water Mixtures Separation

Magnetically driven super-hydrophobic materials were prepared by Fe3O4 nanoparticles and stearic acid,which were deposited on the surface of polyurethane sponges.The presence of the Fe3O4 nanoparticles makes the sponge have the magnetic,and the micro-nano hierarchical structure and hydrophobic functional groups lead to the sponge have excellent superhydrophobicity.The as-prepared sponge exhibited excellent absorption capacities for various oils and organic solvents ranging from 23.8 times to 86.7 times of its own weight.Moreover,the oil separation capacities still keep a high value after 50 cycles of squeezing the saturated absorbed as-prepared sponge.All of these satisfactory properties make the as-prepared sponge as a candidate of ideal absorbents for oily industrial wastewater and oil spills in oceans.

Bi and S Co-doping g-C_(3)N_(4)to Enhance Internal Electric Field for Robust Photocatalytic Degradation and H_(2) Production

By adjusting the type and proportion of doping elements in the g-C_(3)N_(4)-based photocatalyst,the internal electric field(IEF)strength of the semiconductor can be regulated.This can effectively enhance the driving force of charge separation in the photocatalytic process.It is found that the introduction of appropriate concentration of Bi and S into the skeleton structure of g-C_(3)N_(4)can achieve efficient degradation of tetracycline(TC)and other pollutants in the liquid environment and excellent photocatalytic H_(2)evolution performance(1139μmol·L^(-1)·h^(-1)).Since the prepared samples have similar crystal structures,the relative strength of IEF can be calculated.It can be used as the basis for adjusting the IEF strength of g-C_(3)N_(4)-based semiconductor by element doping.In addition,the Bi and S co-doped g-C_(3)N_(4)samples after solvothermal reflux show good chemical stability and can reduce the nanostructure defects caused by co-doping of heteroatoms,thus it provides a novel solution for the construction of g-C_(3)N_(4)-based dual-function photocatalyst with high activity and stability.

Novel organic/inorganic PDI-Urea/BiOBr S-scheme heterojunction for improved photocatalytic antibiotic degradation and H_(2)O_(2) production

The matched energy band structure and efficient carrier separation efficiency are the keys to heterogeneous photocatalytic reactions.A novel organic/inorganic step scheme(S-scheme)heterojunction PDI-Urea/BiOBr composite photocatalyst was constructed by simple solvothermal reaction combined with in-situ growth strategy.The composite photocatalyst not only has high chemical stability,but also can generate and accumulate a large number of active species(h^(+),·O_(2)^(-),·OH,H_(2)O_(2)).PDI-Urea/BiOBr showed higher photocatalytic activity for the degradation of antibiotic such as ofloxacin(OFLO),tetracycline(TC)and the production of H_(2)O_(2) in the spectral range of 400-800 nm.The apparent rate constant of 15%PDI-Urea/BiOBr for photocatalytic degradation of TC(or OFLO)was 2.7(or 2.5)times that of pure BiOBr and 1.7(or 1.8)times that of pure PDI-Urea.The H_(2)O_(2) evolution rate of 15%PDI-Urea/BiOBr was 2.5 times that of PDI-Urea and 1.5 times that of BiOBr,respectively.This work has formed a mature S-scheme heterojunction design thought and method,which offers new visions for the development of heterogeneous photocatalysts.

Dyngo-4a protects mice from rotavirus infection by affecting the formation of dynamin 2 oligomers

Rotavirus is the most common etiologic agent of severe diarrhea in infants and young children and causes more than 200,000 deaths annually worldwide[1,2].Licensed rotavirus vaccines can provide more than 50%protection against rotavirus infection,and currently available etiological treatments for rotavirus gastroenteritis mainly involve the use of oral rehydration solution and zinc supplementation[3].However,targeted interventions are in great need for rotavirus-induced gastroenteritis control.