Application Layer Multicast Model with Low Delay and High Stability

As an alternative of Internet protocol(IP)multicast,application layer multicast(ALM)is widely used with the advantage of simplicity and flexibility.However,the existing problems of large transmission delay and poor stability limit the application and development.In this article,to solve these problems,an ALM model based on node potential(NP)and topological index(TI)is proposed.The proposed model considers the factors of node capability and node distance in constructing and maintaining multicast tree to reduce transmission delay and increase stability,and thus it improves the application level in real-time multimedia multicast.The computer simulations prove that the proposed model reduces the ALM transmission delay,increases multicast tree stability effectively,and improves the ALM performance,and therefore it is suitable to apply in large-scale real-time multimedia environment.

Novel photoelectric material of perovskite-like(CH_(3))_(3)SPbI_(3) nanorod arrays with high stability

Organometallic halide perovskite materials make great achievements in optoelectronic fields,especially in solar cells,in which the organic cations contain amine components.However,the amine with NàH bonds is easily hydrolyzed with moisture in the air,weakening the perovskite materials stability.It is desirable to develop other non-amine stable perovskite materials.In this work,sulfur-based perovskite-like(CH_(3))_(3)SPbI_(3) nanorod arrays were fabricated by a solution-processed method,which can be indexed hexagonal crystal structure in the space group P63 mc.The binding force is exceptionally strong between the non-amine(CH_(3))_(3) S+and[PbI_(6)]_(4)-octahedral,leading to high stability of(CH_(3))_(3)SPbI_(3).The(CH_(3))_(3)SPbI_(3) nanorod arrays can keep the morphology and crystal structure in an ambient atmosphere over 60 days.In addition,the(CH_(3))_(3)SPbI_(3) nanorod arrays can offer direct charge transfer channels,which show excellent optoelectronic properties.The(CH_(3))_(3)SPbI_(3) nanorod arrays-based solar cells with VOx hole transfer layers achieved a power conversion efficiency of 2.07%with negligible hysteresis.And the(CH_(3))_(3)SPbI_(3) nanorod arrays were also effectively applied in photodetectors with interdigitated gold electrodes.This work demonstrates that sulfur-based perovskite-like(CH_(3))_(3)SPbI_(3) is a novel promising stable compound with great potential for practical optoelectronic applications.

1-Methyl-3-octylimidazolium Polyoxomolybdate Ionic Liquid with Low Melting Point and High Stability:Preparation and Photocatalytic Activity

The polyoxometalate（POM）-imidazole ionic liquid（IL） [C8mim]2[Mo6O19]（C8mim=1-methyl-3-octylimi- dazolium） with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, TG and so on. The polyoxomolybdate-based IL has high stability, and its decomposing temperature reaches 321 °C, which is higher than that of 1-alkyl-3-methylimidazolium halides IL. Further photocatalytic performances of the IL were measured via degrading dye rhodamine B（RB） in aqueous solution under the UV light irradiation. The experiments show that the conversion of RB reaches 80.5% after 90 min under UV-light and the degradation efficiency depends on the pH value of the solution, irradiation time and the dosage of the IL and so on.

Constructing energetic covalent organic frameworks with high stability and low sensitivity

Developing new functional explosives that display high stability,good energy performance,and low sensitivity are one of the key directions of energetic materials research.In this work,two-dimensional(2D)Schiff-based energetic covalent organic frameworks(COFs)are prepared based on triaminoguanidine salts with different anions as building blocks.Benefiting from the robust covalent bond in 2D extended polygons and strongπ-πinteractions in the eclipsed interlayers,the synthesized energetic COFs showed higher thermal stability and lower mechanical sensitivity than their precursor salts.More importantly,incorporating triaminoguanidine salts into COFs effectively increase the corrosion resistance to metal under high humidity conditions,which is due to the imine moieties in COFs functioning asπacceptors and offering strong bonding with metallic ions.This work provides a new pathway for the development of high-performance energetic materials.

Effects of Al and Co doping on the structural stability and high temperature cycling performance of LiNi_(0.5)Mn_(1.5)O_(4) spinel cathode materials

The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.

A high-power high-stability Q-switched green laser with intracavity frequency doubling using a diode-pumped composite ceramic Nd:YAG laser

We successfully obtain a high-average-power high-stability Q-switched green laser based on diode-side-pumped composite ceramic Nd：YAG in a straight piano-concave cavity. The temperature distribution in composite ceramic Nd：YAG crystal is numerically analyzed and compared with that of conventional Nd：YAG crystal. By using a composite ceramic Nd：YAG rod and a type-II high gray track resistance KTP （HGTR-KTP） crystal, a green laser with an average output power of 165 W is obtained at a repetition rate of 25 kHz, with a diode-to-green optical conversion of 14.68%, and a pulse width of 162 ns. To the best of our knowledge, both the output power and optical-to-optical efficiency are the highest values for green laser systems with intracavity frequency doubling of this novel composite ceramic Nd：YAG laser to date. The power fluctuation at around 160 W is lower than 0.3% in 2.5 hours.

Two lanthanide(Ⅲ)-copper(Ⅱ) chains based on[Cu_2Ln_2]clusters exhibiting high stability,magnetocaloric effect and slow magnetic relaxation

Two 3d-4f heterometallic one-dimensional chains with neutral 4,4＇-bipyridine ligands as linkers and[Cu2Ln2] clusters （Ln = Gd for 1, Dy for 2） as nodes have been hydrothermally synthesized and structurally characterized. Magnetic studies indicate that complex 1 exhibits a relatively large magnetocaloric effect, with an entropy change -△Smax m= 24.8 J kg 1 K^-1, whilst, complex 2 features slow magnetic relaxation at low temperature.

Excellent Terahertz shielding performance of ultrathin flexible Cu/graphene nanolayered composites with high stability

Electromagnetic interference(EMI)shielding at Terahertz(THz)frequency range attracts increasing attention due to the rapid development of THz science and technologies.EMI shielding materials with small thickness,high shielding effectiveness(SE),good flexibility and stability are highly desirable.Herein,an ultrathin flexible copper/graphene(Cu/Gr)nanolayered composite are prepared,which can reach the average EMI SE of 60.95 dB at 0.1–1.0 THz with a thickness of only 160 nm,indicating that more than 99.9999%of the THz wave power can be shielded.Furthermore,the Cu/Gr nanolayered composite also exhibits excellent oxidation resistance,with a 93.09%maintenance rate for EMI SE value after heating at 120℃for 3 h in air,far higher than that of the bare Cu film(62.15%).Besides,the Cu/Gr nanolayered composite exhibits good mechanical flexibility and flexural fatigue resistance.The EMI SE value of the Cu/Gr nanolayered composite shows a maintenance rate of 98.87%even after 1500 times bending cycles,obviously higher than that of multilayer Cu film(93.07%).These results demonstrate that the ultrathin flexible Cu/Gr nanolayered composites with excellent shielding performance and good stability have a broad application prospect in THz shielding for wearable devices and next generation mobile communication equipment.

In-situ growth of polypyrrole on aramid nanofibers for electromagnetic interference shielding films with high stability

Flexible electromagnetic interference(EMI)shielding films with high stability have shown promising prospect in harsh working conditions such as military,communication,and special protection fields.Herein,flexible aramid nanofibers@polypyrrole(ANF@PPy)films with high stability were easily achieved by the in-situ growth of PPy on the surface of ANF and the subsequent pressured-filtration film-forming process.When the amount of pyrrole(Py)monomer is 40μL,the ANF@PPy(AP40)film exhibited excellent EMI shielding performance with shielding effectiveness(SE)of 41.69 dB,tensile strength of 96.01 MPa,and fracture strain of 21.95%at the thickness of 75.76μm.Particularly,the anticipated EMI shielding performance can be maintained even after being heated at 200℃in air,soaked in 3.5%NaCl solution,repeated folding for one million times,or burned directly,indicating superior environmental durability in harsh conditions.Therefore,it is believed that the ANF@PPy films with high stability offer a facile solution for practical protection for high-performance EMI shielding applications.

A high stability high voltage power supply design for HEPS injection system

Purpose The high energy photon source(HEPS)uses the on-axial injection scheme.There are two designs in this injection scheme that are critical to the performance of the HEPS injection system.One is the strip line kicker and another is the high voltage fast pulse power supply system.In the high voltage fast pulse power supply system,the design of high voltage power supply is very important.The output voltage stability of high voltage power supply directly affects the stability of the pulse amplitude of the injection system.Methods A high voltage power supply with high output voltage stability is designed in this paper,and the scheme is given.The correctness of the design scheme is verified by simulation experiments.Result A prototype is built for full test.The test results showed that the output voltage stability is lower than 58 ppm.The output voltage is 6.4 mV(f≤3 kHz)/113.2 mV(f>3 kHz).Conclusions The designed high voltage power supply can fully meet the requirements of the HEPS injection system.

High Stability Multi-Wavelength Source by Using Synchronized Etalon Filter in Superfluorescent Fiber Source

We demonstrate a new technique to generate a high stability multi-wavelength fiber source by inserting a synchronized etalon filter in superfluorescent fiber source. Multi-wavelength source can easily be obtained over the EDF gain region with the proposed schedule. By partially feedback diffracted spontaneous emission into erbium doped fiber medium, greater output power, extinction ration and narrower linewidth for each channel than that simply using the spectrum slicing technique is easy obtained. Stab...

High-entropy L1_(2)-Pt(FeCoNiCuZn)_(3) intermetallics for ultrastable oxygen reduction reaction

Enhancing the stability of Pt-based electrocatalysts for the sluggish cathodic oxygen reduction reaction(ORR)is critical for proton exchange membrane fuel cells(PEMFCs).Herein,high-entropy intermetallic(HEI)L1_(2)-Pt(FeCoNiCuZn)3is designed for durable ORR catalysis.Benefiting from the unique HEI structure and the enhanced intermetallic phase stability,Pt(FeCoNiCuZn)3/C nanoparticles demonstrate significantly improved stability over Pt/C and PtCu_(3)/C catalysts.The Pt(FeCoNiCuZn)3/C exhibits a negligible decay of the half-wave potential during 30,000 potential cycles from 0.6 to 1.0 V,whereas Pt/C and PtCu_(3)/C are negatively shifted by 46 and 36 m V,respectively.Even after 10,000 cycles at potential up to 1.5 V,the mass activity of Pt(FeCoNiCuZn)3/C still shows~70%retention.As evidenced by the structural characterizations,the HEI structure of Pt(FeCoNiCuZn)3/C is well maintained,while PtCu_(3)/C nanoparticles undergo severe Cu leaching and particle growth.In addition,when assembled Pt(FeCoNiCuZn)3/C as the cathode in high-temperature PEMFC of 160℃,the H_(2)-O_(2)fuel cell delivers almost no degradation even after operating for 150 h,demonstrating the potential for fuel cell applications.This work provides a facile design strategy for the development of high-performance ultrastable electrocatalysts.

Rational Design of Porous N-Ti3C2 MXene@CNT Microspheres for High Cycling Stability in Li–S Battery

Herein,N-Ti3C2@CNT microspheres are successfully synthesized by the simple spray drying method.In the preparation process,HCl-treated melamine(HTM)is selected as the sources of carbon and nitrogen.It not only realizes in situ growth of CNTs on the surface of MXene nanosheets with the catalysis of Ni,but also introduces efficient N-doping in both MXene and CNTs.Within the microsphere,MXene nanosheets interconnect with CNTs to form porous and conductive network.In addition,N-doped MXene and CNTs can provide strong chemical immobilization for polysulfides and effectively entrap them within the porous microspheres.Above-mentioned merits enable N-Ti3C2@CNT microspheres to be ideal sulfur host.When used in lithium–sulfur(Li–S)battery,the N-Ti3C2@CNT microspheres/S cathode delivers initial specific capacity of 927 mAh g−1 at 1 C and retains high capacity of 775 mAh g−1 after 1000 cycles with extremely low fading rate(FR)of 0.016%per cycle.Furthermore,the cathode still shows high cycling stability at high C-rate of 4 C(capacity of 647 mAh g−1 after 650 cycles,FR 0.027%)and high sulfur loading of 3 and 6 mg cm−2 for Li–S batteries.

Enhanced Anion-Derived Inorganic-Dominated Solid Electrolyte Interphases for High-Rate and Stable Sodium Storage

It is highly desirable for the promising sodium storage possessing high rate and long stable capability,which are mainly hindered by the unstable yet conventional solvent-derived organic-rich solid electrolyte interphases.Herein,an electrolyte solvation chemistry is elaborately manipulated to produce an enhanced anion-derived and inorganic components-dominated solid electrolyte interphases by introducing a low permittivity(4.33)bis(2,2,2-trifluoroethyl)ether diluent into the sodium bis(trifluoromethylsulfonyl)imidedimethoxyethane-based high concentration electrolyte to obtain a localized high concentration electrolyte.The bis(2,2,2-trifluoroethyl)ether breaks the balance of original cation solvation structure and tends to interact with Na^(+)-coordinated dimethoxyethane solvent rather than Na^(+)in high concentration electrolyte,leaving an enhanced Coulombic interaction between Na^(+)and(FSO_(2))_(2)N^(-),and more(FSO_(2))_(2)N^(-)can enter the Na^(+)solvation shell,forming a further increased number of Na^(+)-(FSO_(2))_(2)N^(-)-dimethoxyethane clusters(from 82.0%for high concentration electrolyte to 94.3%for localized high concentration electrolyte)at a low salt dosage.The preferential reduction of this(FSO_(2))_(2)N^(-)-enriched clusters rather than the dimethoxyethane-dominated Na^(+)solvation structure produces an enhanced anion-derived and inorganic components-dominated solid electrolyte interphases.The reversible charge storage process of Na is decoupled by operando Raman along with a shift of D and G peaks.Benefiting from the enhanced anion-derived electrode-electrolyte interface,the commercial hard carbon anode in localized high concentration electrolyte shows a well rate capability(5 A g^(−1),70 mAh g^(−1)),cycle performance and stability(85%of initial capacity after 700 cycles)in comparison to that of high concentration electrolyte(68%)and low concentration electrolyte(only 5%after 400 cycles),indicative of uniqueness and superiorities towards stable Na storage.

High thermal stability of diamond-cBN-B_4C-Si composites

Improving the thermal stability of diamond and other superhard materials has great significance in various applications. Here, we report the synthesis and characterization of bulk diamond–cBN–B4C–Si composites sintered at high pressure and high temperature（HPHT, 5.2 GPa, 1620–1680 K for 3–5 min）. The results show that the diamond, cBN, B4C,BxSiC, SiO2 and amorphous carbon or a little surplus Si are present in the sintered samples. The onset oxidation temperature of 1673 K in the as-synthesized sample is much higher than that of diamond, cBN, and B4C. The high thermal stability is ascribed to the covalent bonds of B–C, C–N, and the solid-solution of BxSiC formed during the sintering process. The results obtained in this work may be useful in preparing superhard materials with high thermal stability.

LaB6 Work Function and Structural Stability under High Pressure

The work functions of the （110） and （10（3） surfaces of LaB6 are determined from ambient pressure to 39.1 GPa. The work function of the （110） surface slowly decreases but that of the （100） surface remains at a relatively constant value. To determine the reason for this difference, the electron density distribution （EDD） is determined from high-pressure single-crystal x-ray diffraction data by the maximum entropy method. The EDD results show that the chemical bond properties in LaB6 play a key role also investigated by single-crystal x-ray diffraction. In observed from ambient pressure to 39.1 GPa. The structural stability of LaB6 under high pressure is this study, no structural or electronic phase transition is

Highly sensitive and stable probe refractometer based on configurable plasmonic resonance with nano-modified fiber core

A dispersion model is developed to provide a generic tool for configuring plasmonic resonance spectral characteristics.The customized design of the resonance curve aiming at specific detection requirements can be achieved.According to the model,a probe-type nano-modified fiber optic configurable plasmonic resonance(NMF-CPR)sensor with tip hot spot enhancement is demonstrated for the measurement of the refractive index in the range of 1.3332-1.3432 corresponding to the low-concentration biomarker solution.The new-type sensing structure avoids excessive broadening and redshift of the resonance dip,which provides more possibilities for the surface modification of other functional nanomaterials.The tip hot spots in nanogaps between the Au layer and Au nanostars(AuNSs),the tip electric field enhancement of AuNSs,and the high carrier mobility of the WSe_(2)layer synergistically and significantly enhance the sensitivity of the sensor.Ex-perimental results show that the sensitivity and the figure of merit of the tip hot spot enhanced fiber NMF-CPR sensor can achieve up to 2995.70 nm/RIU and 25.04 RIU^(−1),respectively,which are 1.68 times and 1.29 times higher than those of the conventional fiber plasmonic resonance sensor.The results achieve good agreements with numerical simulations,demonstrate a better level compared to similar reported studies,and verify the correctness of the dispersion model.The detection resolution of the sensor reaches up to 2.00×10^(−5)RIU,which is obviously higher than that of the conventional side-polished fiber plasmonic resonance sensor.This indicates a high detection accuracy of the sensor.The dense Au layer effectively prevents the intermediate nanomaterials from shedding and chemical degradation,which enables the sensor with high stability.Furthermore,the terminal reflective sensing structure can be used as a practical probe and can allow a more convenient operation.

Highly active and stable Co nanoparticles embedded in nitrogen-doped mesoporous carbon nanofibers for aqueous-phase levulinic acid hydrogenation

Developing a highly active and durable non-noble metal catalyst for aqueous-phase levulinic acid(LA)hydrogenation to g-valerolactone(GVL)is an appealing yet challenging task.Herein,we report well-dispersed Co nanoparticles(NPs)embedded in nitrogen-doped mesoporous carbon nanofibers as an efficient catalyst for aqueous-phase LA hydrogenation to GVL.The Co zeolitic imidazolate framework(ZIF-67)nanocrystals were anchored on the sodium dodecyl sulfate modified wipe fiber(WF-S),yielding one-dimensional(1-D)structured composite(ZIF-67/WF-S).Subsequently,Co NPs were uniformly embedded in nitrogen-doped mesoporous carbon nanofibers(Co^(R)NC/SMCNF)through a pyrolysis-reduction strategy using ZIF-67/WF-S as the precursor.Benefiting from introducing modified wipe fiber WF-S to enhance the dispersion of Co NPs,and Co^(0) with Co-N_xdual active sites,the resulting Co^(R)NC/SMCNF catalyst shows brilliant catalytic activity(206 h^(-1) turnover frequency).Additionally,the strong metal-support interactions greatly inhibited the Co NPs from aggregation and leaching from the mesoporous carbon nanofibers,and thus increasing the reusability of the Co^(R)NC/SMCNF catalyst(reusable nine times without notable activity loss).

Overcoming the Na-ion conductivity bottleneck for the cost-competitive chloride solid electrolytes

Chloride solid electrolytes possess multiple advantages for the construction of safe,energy-dense allsolid-state sodium batteries,but presently the chlorides with sufficiently high cost-competitiveness for commercialization almost all exhibit low Na-ion conductivities of around 10^(-5)S cm^(-1)or lower.Here,we report a chloride solid electrolyte,Na_(2.7)ZFCl_(5.3)O_(0.7),which reaches a Na-ion conductivity of 2.29×10^(-4)S cm^(-1)at 25℃without involving overly expensive raw materials such as rare-earth chlorides or Na_(2)S.In addition to the efficient ion transport,Na_(2.7)ZrCl_(5.3)O_(0.7)also shows an excellent deformability surpassing that of the widely studied Na_(3)PS_(4),Na_(3)SbS_(4),and Na_(2)ZrCl_(6)solid electrolytes.The combination of these advantages allows the all-solid-state cell based on Na_(2.7)ZrCl_(5.3)O_(0.7)and NaCrO_(2)to realize stable room-temperature cycling at a much higher specific current than those based on other non-viscoelastic chloride solid electrolytes in literature(120 mA g^(-1)vs.12-55 mA g^(-1));after 100 cycles at such a high rate,the Na_(2.7)ZFCl_(5.3)O_(0.7)-based cell can still deliver a discharge capacity of 80 mAh g^(-1)at25℃.

Effect of yttrium and manganese addition on catalytic soot combustion activity and anti-high-temperature stability of CeO_(2) catalyst

In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO_(2) catalyst,a series of Y/Mn-modified CeO_(2) catalysts were prepared.The effects of structural properties,textural properties,oxygen vacancies,Ce^(3+),surface adsorbed oxygen species,reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods.The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity,while the addition of yttrium increases the amount of reactive oxygen species,but decreases the activity.After aging at 700℃,the activity of the CeMn catalyst decreases most sharply,while the catalytic activity of the CeY catalyst can be maintained to a certain extent.Interestingly,the addition of yttrium and manganese at the same time can stabilize the activity.The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging,which increases the reduction performance of the catalyst,thus contributing to the increase of activity.Although the activity of CeYMn catalyst decreases after aging at 800℃,it is still higher than that of other catalysts aged at 700℃.