吩嗪类衍生物用于快速充放电和长寿命的水系钾离子全电池负极

有机电极材料因具有结构多样性和可持续性,在水系钾离子电池研究领域展示出广阔的前景,但它们大多数存在导电性差、易溶于电解液的问题,导致电极活性物质利用率低、循环稳定性差.本文通过含氮苯环的共轭延申、引入氰基活性中心,获得了3CN-HATN.与经#吩嗪负极相比,3CN-HATN的最低未占据分子轨道能级更低,更容易被还原,且其能带隙较窄,改善了导电性,其共轭结构可有效抑制循环过程中3CN-HATN的溶解.3CN-HATN负极在80 C(1 C=350 mA g^(-1))下比容量高达233.8 mA h g^(-1),将其与Ni(OH)_(2)正极匹配,构建的水系钾离子全电池具备优异的循环稳定性和快充性能,30 C下循环10,000圈后容量保持率达81.5%.

Halogen-bond induced unusual polyhalogen anions formation in hydrogen-bonded frameworks to secure iodine sequestration

Safe confinement of fission iodine isotopes for long-term radioactive waste disposal remains a formidable challenge,as conventional sorbents provide inherently weak iodine-host interactions.We report here a novel halogen bond(X-bond)directed strategy to sequester volatile iodine in hydrogen-bonded(H-bonded)frameworks with unprecedented stability.Charge-assisted Hbonded frameworks bearing open halide sites are developed,showing distinctive iodine encapsulation behaviors without compromising the crystallinity.Direct crystallographic evidence indicates the formation of X-bonds,i.e.,I–I···Cl−and I–I···Br^(−),within the confined pore channels.Unusual polyhalogen anions,i.e.,[I_(2)Cl_(2)]^(2−)and[I_(2)Br_(2)]^(2−),sustained in H-bonded frameworks are identified for the first time.The X-bond reinforced host-guest interaction affords robust iodine trapping without leaking out even at elevated temperatures up to 180°C.By integrating the halogen-bond chemistry with H-bonded frameworks,this study offers fresh concepts for developing effective host reservoirs to secure fission iodine isotopes from spent fuel reprocessing off-gases.

EDGE SP1000单孔手术机器人辅助腹腔镜下猪输尿管部分切除联合端端吻合术的可行性研究

目的利用活体猪模型评估EDGE SP1000单孔机器人辅助腹腔镜输尿管部分切除联合端端吻合术的安全性和可行性。方法利用EDGE SP1000单孔机器人手术系统开展腹腔镜下猪输尿管部分切除联合端端吻合术。监测手术过程中猪的生命体征,记录手术困难点和并发症,观察术后2周猪的存活情况。结果所有猪均存活至术后两周,手术过程中未出现并发症,也未遇到技术困难。5头猪建立手术通道的平均时间为(15.0±1.2)min,安装EDGE SP1000单孔手术机器人系统时间为(5.6±0.6) min,输尿管部分切除时间为(8.8±1.3) min,输尿管端端吻合时间为(39.2±2.3) min,总手术时间为(89±5) min,术中出血量为(1.20±0.24)mL。使用该手术系统的外科医师和助手均对系统的工作给予了高度评价。结论本研究证实EDGE SP1000单孔机器人手术系统用于猪输尿管部分切除联合端端吻合术是安全可行的。下一步拟开展EDGE SP1000系统在其他外科手术中的安全性和有效性评价,提供更多可靠的临床前数据支撑。

Experimental study on NO_x emission correlation of fuel staged combustion in a LPP combustor at high pressure based on NO-chemiluminescence

Experimental investigations on NOx emissions of a single-cup,Lean Premixed Prevaporized(LPP),module combustor were carried out at elevated inlet temperature and pressure up to810 K and 2.0 MPa,close to the real operating conditions of aero-engine combustors.This LPP combustor adopts centrally staged fuel injections which could produce separated stratified swirling spray flame.In the NOx emissions measurements,the ranges of dome equivalence ratio and fuel stage ratio were from 0.55 to 0.58 and 8%to 24%,respectively.The optical diagnosis on separated stratified swirling spray flame were carried out with fuel stage ratio changing from 15%to 30%.Therefore,NO*and OH*chemiluminescence images were obtained.The results show that NOx emissions increase with the increase of the fuel stage ratio.And from the chemiluminescence images,the main flame and pilot flame are found weakly coupled.The pilot flame plays a significant role in NOx emission production because of its higher adiabatic flame temperature.Based on the results of chemiluminescence optical tests,a new NOx emission prediction model is proposed based on the Lefebvre’s single flame model The estimate of local equivalence ratio of the pilot stage’s nonpremixed flame is modified considering the characteristics of spray combustion,and a"PLUS"emission prediction model suitable for separated stratified swirling spray flame is obtained.Compared to the experimental data,the"PLUS"model exhibits a good prediction in a range of±13%of deviation.

Experimental investigations of the spray structure and interactions between sectors of a double-swirl low-emission combustor

In this paper,the spray characteristics of a double-swirl low-emission combustor are analyzed by using Particle Imaging Velocimetry(PIV)and Planar Laser Induced Fluorescence(PLIF)technologies in an optical three-sector combustor test rig.Interactions between sectors and the influence of main stage swirl intensity on spray structure are explained.The results illustrate that the swirl intensity has great effect on the flow field and spray structure.The spray cone angle is bigger when the swirl number is 0.7,0.9 than that when the swirl number is 0.5.The fuel distribution zone is larger and the distribution is more uniform when the swirl number is 0.5.The fuel concentration in the center area of the center plane of side sector(Plane 5)is larger than that of the center plane of middle sector(Plane 1).The spray cone angle in Plane 5 is larger than that in Plane 1.The width of spray cone becomes larger with the increase of Fuel-Air Ratio(FAR),whereas the spray cone angle under different fuel-air ratios are absolutely the same.The results of the mechanism of spray organization in this study can be used to support the design of new low-emission combustor.

Enhanced oxygen reduction kinetics by a porous heterostructured cathode for intermediate temperature solid oxide fuel cells

A novel porous heterostructured Nd_(0.8)Sr_(1.2)CoO_(4)±/Nd_(0.5)Sr_(0.5)CoO_(3-δ)(NSC_(214/113))cathode for intermediate tem-perature solid oxide fuel cells(IT-SOFCs)is developed to significantly enhance oxygen reduction reaction(ORR)kinetics.Compared to single-phase materials,the fabricated porous heterostructured NSC 214/113 shows optimized electrochemical properties,including a better conductivity,20 times faster surface oxygen exchange kinetics,and a comparatively lower area-specific resistance(0.065Ωcm^(2) at 800℃).The single cell with Ni-YSZ|YSZ-GDC|NSC_(214/113) configuration exhibits a high peak power density of 1.10 W cm^(−2) at 800℃,superior to other cells reported in literature with similar heterostructured cathodes.Moreover,the underlying mechanism of the ORR performance enhancement is further investigated,revealing that the formation of heterojunction can lead to a narrowed energy bandgap and a decrease of Co oxidation state,which further induce better conductivity,more available electrons and oxygen vacancies to enhance the ORR process.Taken together,our research also provides new insights into potential application of artificial intelligence(AI)method involved in materials in-telligent identification,cell state estimation,system diagnostic and optimization.The revolutionary force of AI,especially in the field of new electrode material development is now advancing in its full swing.More and greater breakthroughs are still expected.