Composition optimization and performance prediction for ultra-stable water-based aerosol based on thermodynamic entropy theory

Water-based aerosol is widely used as an effective strategy in electro-optical countermeasure on the battlefield used to the preponderance of high efficiency,low cost and eco-friendly.Unfortunately,the stability of the water-based aerosol is always unsatisfactory due to the rapid evaporation and sedimentation of the aerosol droplets.Great efforts have been devoted to improve the stability of water-based aerosol by using additives with different composition and proportion.However,the lack of the criterion and principle for screening the effective additives results in excessive experimental time consumption and cost.And the stabilization time of the aerosol is still only 30 min,which could not meet the requirements of the perdurable interference.Herein,to improve the stability of water-based aerosol and optimize the complex formulation efficiently,a theoretical calculation method based on thermodynamic entropy theory is proposed.All the factors that influence the shielding effect,including polyol,stabilizer,propellant,water and cosolvent,are considered within calculation.An ultra-stable water-based aerosol with long duration over 120 min is obtained with the optimal fogging agent composition,providing enough time for fighting the electro-optic weapon.Theoretical design guideline for choosing the additives with high phase transition temperature and low phase transition enthalpy is also proposed,which greatly improves the total entropy change and reduce the absolute entropy change of the aerosol cooling process,and gives rise to an enhanced stability of the water-based aerosol.The theoretical calculation methodology contributes to an abstemious time and space for sieving the water-based aerosol with desirable performance and stability,and provides the powerful guarantee to the homeland security.

Oxygen functionalization-assisted anionic exchange toward unique construction of flower-like transition metal chalcogenide embedded carbon fabric for ultra-long life flexible energy storage and conversion

The metal-organic framework(MOF)derived Ni–Co–C–N composite alloys(NiCCZ)were“embedded”inside the carbon cloth(CC)strands as opposed to the popular idea of growing them upward to realize ultrastable energy storage and conversion application.The NiCCZ was then oxygen functionalized,facilitating the next step of stoichiometric sulfur anion diffusion during hydrothermal sulfurization,generating a flower-like metal hydroxysulfide structure(NiCCZOS)with strong partial implantation inside CC.Thus obtained NiCCZOS shows an excellent capacity when tested as a supercapacitor electrode in a three-electrode configuration.Moreover,when paired with the biomass-derived nitrogen-rich activated carbon,the asymmetric supercapacitor device shows almost 100%capacity retention even after 45,000 charge–discharge cycles with remarkable energy density(59.4 Wh kg^(-1)/263.8μWh cm^(–2))owing to a uniquely designed cathode.Furthermore,the same electrode performed as an excellent bifunctional water-splitting electrocatalyst with an overpotential of 271 mV for oxygen evolution reaction(OER)and 168.4 mV for hydrogen evolution reaction(HER)at 10 mA cm−2 current density along with 30 h of unhinged chronopotentiometric stability performance for both HER and OER.Hence,a unique metal chalcogenide composite electrode/substrate configuration has been proposed as a highly stable electrode material for flexible energy storage and conversion applications.

Highly Thermally Conductive and Structurally Ultra‑Stable Graphitic Films with Seamless Heterointerfaces for Extreme Thermal Management

Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.

Transportable 1555-nm Ultra-Stable Laser with Sub-0.185-Hz Linewidth

We present two cavity-stabilized lasers at 1555 nm, which are built to be the frequency source for a transportable photonic microwave generation system. The frequency instability reaches the thermal noise limit （7 ×10-16） of the 10-cm ultra-low expansion glass cavity at 1-10s averaging time and the beat signal of the two lasers reveals a remarkable linewidth of 185mHz.

Industrial Preparation and Acid Resistance of Ultra-stable Y Zeolite with Small Cell Size Produced by Gas-phase Method

Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resistance of industrially prepared HSY-S was investigated by acid solutions with different pH values.The structures and properties of HSY-S and its acid-treated samples were characterized by XRD,XRF,BET,and IR.Results show that the HSY-S samples have the characteristics of high crystallinity,good stability,large specific surface area,and good acid resistance.

Ultra-stable and High-rate Lithium Ion Batteries Based on Metal-organic Framework-derived ln2O3 Nanocrystals/Hierarchically Porous Nitrogen-doped Carbon Anode

Exploring electrode materials with attractive specific capacity and prominent cyclic durability is of the essence for promoting lithium ion batteries(LIBs).In2O3 has shown an extraordinary promise for LIBs with advantageous gravimetric capacity(theoretically 965 mA h g-1) and low working voltage.However,In2O3 still suffers from the inherent weaknesses of metal oxides in practical application,especially low conductivity and incorrigible volume expansion upon the cycling process.Here,we demonstrate the architecture of metal-organic framework(MOF)-derived In2O3 nanocrystals/hierarchically porous nitrogen-doped carbon composite(In2O3/HPNC) for ultra-stable LIBs anode.This hierarchically porous structure(micro/meso/macro-pores) with nitrogen doping not only ensures exceptional mechanical strength and accommodates the volume expansion of In2O3 nanocrystals,but also offers electrons and lithium ions efficient interpenetrating pathways to migrate rapidly during charge/discharge processes.Thus,In2O3/HPNC exhibits excellent cyclic stability with a high specific capacity of 623 mA h g-1 over2000 cycles at 1000 mA g-1,corresponding to an ultra-low specific capacity decay of 0.017% per cycle(the best among the ln203-based anode for LIBs),and outstanding rate performance,suggesting a critical step toward achieving long-life and high-rate LIBs in practical devices.

Ultra-stable near-infrared Tm^(3+)-doped upconversion nanoparticles for in vivo wide-field two-photon angiography with a low excitation intensity

Two-photon luminescence with near-infrared(NIR)excitation of upconversion nanoparticles(NPs)is of great importance in biological imaging due to deep penetration in high-scattering tissues,low auto-luminescence and good sectioning ability.Unfortunately,common two-photon luminescence is in visible band with an extremely high exciation power density,which limits its application.Here,we synthesized NaYF_(4):Yb/Tm@NaYF_(4)upconversion NPs with strong twophoton NIR emission and a low excitation power density.Furthermore,NaYF_(4):Yb/Tm@NaYF_(4)@SiO_(2)@OTMS@F127 NPs with high chemical stability were obtained by a modified multilayer coating method which was applied to upconversion NPs for thefirst time.In addition,it is shown that the as-prepared hydrophillic upconversion NPs have great biocompatibility and kept stable for 6 hours during in vivo whole-body imaging.The vessels with two-photon luminescence were clear even under an excitation power density as low as 25mW/cm^(2).Vivid visualizations of capillaries and vessels in a mouse brain were also obtained with low background and high contrast.Because of cheaper instruments and safer power density,the NIR two-photon luminescence of NaYF_(4):Yb/Tm@NaYF_(4)upconversion NPs could promote wider application of two-photon technology.The modified multilayer coating method could be widely used for upconversion NPs to increase the stable time of the in vivo circulation.Our work possesses a great potential for deep imaging and imaging-guided treatment in the future.

Niobium Tungsten Oxide in a Green Water‑in‑Salt Electrolyte Enables Ultra‑Stable Aqueous Lithium‑Ion Capacitors

Aqueous hybrid supercapacitors are attracting increasing attention due to their potential low cost,high safety and eco-friendliness.However,the narrow operating potential window of aqueous electrolyte and the lack of suitable negative electrode materials seriously hinder its future applications.Here,we explore high concentrated lithium acetate with high ionic conductivity of 65.5 mS cm−1 as a green“water-in-salt”electrolyte,providing wide voltage window up to 2.8 V.It facilitates the reversible function of niobium tungsten oxide,Nb18W16O93,that otherwise only operations in organic electrolytes previously.The Nb18W16O93 with lithium-ion intercalation pseudocapacitive behavior exhibits excellent rate performance,high areal capacity,and ultra-long cycling stability.An aqueous lithium-ion hybrid capacitor is developed by using Nb18W16O93 as negative electrode combined with graphene as positive electrode in lithium acetate-based“water-in-salt”electrolyte,delivering a high energy density of 41.9 W kg−1,high power density of 20,000 W kg−1 and unexceptionable stability of 50,000 cycles.

Water‑Dispersible CsPbBr_(3) Perovskite Nanocrystals with Ultra‑Stability and its Application in Electrochemical CO_(2) Reduction

Thanks to the excellent optoelectronic properties,lead halide perovskites(LHPs)have been widely employed in highperformance optoelectronic devices such as solar cells and lightemitting diodes.However,overcoming their poor stability against water has been one of the biggest challenges for most applications.Herein,we report a novel hot-injection method in a Pb-poor environment combined with a well-designed purification process to synthesize water-dispersible CsPbBr_(3) nanocrystals(NCs).The as-prepared NCs sustain their superior photoluminescence(91%quantum yield in water)for more than 200 days in an aqueous environment,which is attributed to a passivation effect induced by excess CsBr salts.Thanks to the ultra-stability of these LHP NCs,for the first time,we report a new application of LHP NCs,in which they are applied to electrocatalysis of CO_(2) reduction reaction.Noticeably,they show significant electrocatalytic activity(faradaic yield:32%for CH4,40%for CO)and operation stability(>350 h).

Study of optical clocks based on ultracold ^171Yb atoms

The optical atomic clocks have the potential to transform global timekeeping,relying on the state-of-the-art accuracy and stability,and greatly improve the measurement precision for a wide range of scientific and technological applications.Herein we report on the development of the optical clock based on 171Yb atoms confined in an optical lattice.A minimum width of 1.92-Hz Rabi spectra has been obtained with a new 578-nm clock interrogation laser.The in-loop fractional instability of the 171Yb clock reaches 9.1×10-18 after an averaging over a time of 2.0×104 s.By synchronous comparison between two clocks,we demonstrate that our 171Yb optical lattice clock achieves a fractional instability of 4.60×10-16/√τ.

Photonic generation of RF and microwave signal with relative frequency instability of 10^(-15)

We demonstrate the ultra-stable frequency sources aiming to improve the short-time instability of primary frequency standards. These sources are realized by using photonic generation approach, and composed of ultra-stable lasers, optical- frequency-combs, optical signal detecting parts, and synthesizers. Preliminary evaluation shows that the sources produce fixed-frequency at 9.54（/9.63） GHz, 10 MHz, and tunable-frequency around 9.192 GHz with relative frequency instability of 10^-15 for short terms.

Progress on the use of satellite technology for gravity exploration

In this paper, the technological progress on Chinese gravity exploration satellites is presented. Novel features such as ultra-stable structure, high accurate thermal control, drag-free and attitude control, micro-thrusters, aerodynamic configuration, the ability to perform micro-vibration analyses, microwave ranging system and mass center trimmer are described.

3D uniform nitrogen-doped carbon skeleton for ultra-stable sodium metal anode

Sodium metal batteries are arousing extensive interest owing to their high energy density,low cost and wide resource.However,the practical development of sodium metal batteries is inherently plagued by the severe volume expansion and the dendrite growth of sodium metal anode during long cycles under high current density.Herein,a simple electrospinning method is applied to construct the uniformly nitrogen-doped porous carbon fiber skeleton and used as three-dimensional(3D)current collector for sodium metal anode,which has high specific surface area(1,098 m^2/g)and strong binding to sodium metal.As a result,nitrogen-doped carbon fiber current collector shows a low sodium deposition overpotential and a highly stable cyclability for 3,500 h with a high coulombic effciency of 99.9%at 2 mA/cm^2 and 2 mAh/cm^2.Moreover,the full cells using carbon coated sodium vanadium phosphate as cathode and sodium pre-plated nitrogen-doped carbon fiber skeleton as hybrid anode can stably cycle for 300 times.These results illustrate an effective strategy to construct a 3D uniformly nitrogen-doped carbon skeleton based sodium metal hybrid anode without the formation of dendrites,which provide a prospect for further development and research of high performance sodium metal batteries.

Optically actuating ultra-stable radicals in a large π-conjugated ligand constructed photochromic complex

Producing ultra-stabilized radicals via light irradiation has raised considerable concern but remains a tremendous challenge in functional materials. Herein, optically actuating ultra-stable radicals are discovered in a sterically encumbered and large π-conjugated tri(4-pyridyl)-1,3,5-triazine(TPT) ligands constructed photochromic compound Cu_(3)(H-HEDP)_(2)TPT_(2)·2H_(2)O(QDU-12;HEDP=hydroxyethylidene diphosphonate). The photogeneration of TPT· radicals is the photoactive behavior of electron transfer from HEDP motifs to TPT units. The ultra-long-lived radicals are contributed from strong interchain π-π interactions between the large π-conjugated TPT components, with the radical lifetime maintained for about 18 months under ambient conditions. Moreover, the antiferromagnetic couplings between TPT· radicals and Cu^(2+)ions plummeted the demagnetization to 35% of its original state after light irradiation, showing the largest room temperature photodemagnetization in the current radicalbased photochromic materials.

A multimode-fused sensory memory system based on a robust self-assembly nanoscaffolded BaTiO_(3):Eu_(2)O_(3) memristor

Biologically inspired neuromorphic sensory memory systems based on memristor have received a lot of attention in the booming artificial intelligence industry due to significant potential to effectively process multi-sensory signals from complex external environments.However,many memristors have significant switching parameters disperse,which is a great challenge for using memristors in bionic neuromorphic sensory memory systems.Herein,a stable ferroelectric memristor based on the Pd/BaTiO_(3):Eu2O_(3)/La0.67Sr0.33MnO_(3)grown on Silicon structure with SrTiO_(3)as buffer layer is presented.The device possesses low coercive field voltage(-1.3-2.1 V)and robust endurance characteristic(~10^(10)cycles)through optimizing the growth temperature.More importantly,an ultra-stable artificial multimodal sensory memory system with visual and tactile functions was reported for the first time by combining a pressure sensor,a photosensitive sensor,and a robotic arm.Utilizing the above system,the sensitivity value of the system is expressed by the conductance of the memristor to realize the gradual change of external stimulus,and multi signals inputs at the same time to this system have faithfully achieved sensory adaptation to multimodal sensors.This work paves the way for future development of memristor-based perception systems in efficient multisensory neural robots.

High Li^(+)coordinated solvation sheaths enable high-quality Li metal anode

An advance Li-sphere possessing a definitely regular morphology in Li deposition enables a well-defined more robust structure and superior solid-electrolyte interphase(SEI)to achieve high-efficiency long-term cycles in Li metal anode.Here,a new sight of high Li^(+)cluster-like solvation sheaths coordinated in a localized high-concentration NO_(3)^(-)(LH-LiNO_(3))electrolyte fully clarifies for depositing advanced Li spheres.Moreover,we elucidate a critical amorphouscrystalline phase transition in the nanostructure evolution of Li-sphere deposits during the nucleation and growth.Li-sphere anode exhibits ultrastable structural engineering for suppressing Li dendrite growths and rendering ultralong life of 4000 cycles in symmetrical cells at 2 mAcm^(-2).The as-constructed Li spheres/3DCMjLiFePO_(4)(LFP)full cell delivers a high capacity retention of 90.5%at 1 C after 1000 cycles,and a robust dendrite-free structure also stably exists in Li-sphere anode.Combined with high-loading LFP cathodes(6.6 and 10.9 mg cm^(-2)),superb capacity retentions are up to 96.5%and 92.5%after 800 cycles at 1 C,respectively.Cluster-like solvation sheaths with high Li^(+)coordination exert significant influence on depositing a highquality Li-sphere anode.

Twistor-based synchronous sliding mode control of spacecraft attitude and position

A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter（MRP）.To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative（PD） control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances.

Oil-polluted water purification via the carbon-nanotubes-doped organohydrogel platform

Solar-driven evaporators are promising for tackling freshwater scarcity but still challenged in simultaneously realizing comprehensive performances at one platform for sustainable and efficient application in real-world environments,such as stablefloating,scalability,salt-resistance,efficient vaporization,and anti-oil-fouling property.Herein,we design a hybrid organohydrogel evaporator to achieve the enduring oil contamination repulsion with maintaining accelerated evaporation process,and integrate capacities of ultra-stable floating,hindered salt-crystallization,large-scale fabrication for practical purification of seawater and polluted solutions.The raised water surface surrounding evaporators,induced by low density of organogel-phase,results in oil contamination resistance through the lateral capillary repulsion effect.Meanwhile,the organogel-phase containing photo-thermal carbon-nanotubes with low thermal capacity and conduction can form locally confined hot dots under solar irradiation and reduce heat dissipation on heating excessive water.Therefore,based on this approach,accelerated long-term practical purification of oilcontaminated solutions without any extra disposal is realized.Considering other properties of ultra-stable floating,large-scale fabrication,and anti-salt crystallization,these innovative organohydrogel evaporators open pathways for purifying oil-slickpolluted water via interfacial evaporation and are anticipated accelerating industrialization of efficient and sustainable solar-driven water purification.

Ultrasensitive and stable all graphene field-effect transistor-based Hg^(2+)sensor constructed by using different covalently bonded RGO films assembled by different conjugate linking molecules

As"molecular bridge,"coupling agents can not only realize the covalent connection of composites,but also affect their properties,thus affecting the properties of devices based on them.Herein,leveraging differences in charge conduction properties of the(3-aminopropyl)trimethoxysilane and 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphine caused by conjugacy structural differences,two kinds of layerby-layer assembled smart carbon materials with different electrical properties are obtained at the same reduction temperature.The two graphene ultrathin films are then“planted”on Si/SiO2 substrates,respectively,as semiconductor layer and source/drain electrodes to fabricate an ultra-stable all-graphene field effect transistor(AG-FET).Enabled by the covalent functionalized configuration and the functionally diverse of coupling agents,the AG-FET obtained by this simple method won the high electrical characteristics,the hole,electron mobility,and the shelflife could reach 3.79 cm2/(V·s),3.78 cm2/(V·s),and 18months,respectively.In addition,good material stability and excellent device structure endow the device exceptional stability,electrical stability,and solvent resistance,improving its application prospect in solution phase sensing/detection.Such characteristics could be used to sense,transduce,and respond to external stimuli,especially in solution phase to monitor the important analytes,such as Hg^(2+)in a flowing sewage environment.We believe that such easy-to-manufacture AG-FETs with ultrahigh performance and ultrahigh stability could also show great application prospects in other significant fields.

All-fiber-based photonic microwave generation with 10^(-15) frequency instability

We demonstrate an all-fiber-based photonic microwave generation with 10^(-15) frequency instability.The system consists of an ultra-stable laser by optical fiber delay line,an all-fiber-based"figure-of-nine"optical frequency comb,a high signal-tonoise ratio photonic detection unit,and a microwave frequency synthesizer.The whole optical links are made from optical fiber and optical fiber components,which renders the whole system compactness,reliability,and robustness with respect to environmental influences.Frequency instabilities of 3.5×10^(-15) at 100 s for 6.834 GHz signal and 4.3×10^(-15) at 100 s for9.192 GHz signal were achieved.