Semi-interpenetrating-network all-solid-state polymer electrolyte with liquid crystal constructing efficient ion transport channels for flexible solid lithium-metal batteries

The development of the solid-state polymer electrolytes (SPEs) for Li-ion batteries (LIBs) can effectively address the hidden safety issues of commercially used liquid electrolytes.Nevertheless,the unsatisfactory room temperature ion conductivity and inferior mechanical strength for linear PEO-based SPEs are still the immense obstacles impeding the further applications of SPEs for large-scale commercialization.Herein,we fabricate a series of semi-interpenetrating-network (semi-IPN) polymer electrolytes based on a novel liquid crystal (C6M LC) and poly(ethylene glycol) diglycidyl ether (PEGDE) via UV-irradiation at the first time.The LCs not only highly improve the mechanical properties of electrolyte membranes via the construction of network structure with PEGDE,but also create stable ion transport channels for ion conduction.As a result,a free-standing flexible SPE shows outstanding ionic conductivity(5.93×10^(-5) S cm^(-1) at 30℃),a very wide electrochemical stability window of 5.5 V,and excellent thermal stability at thermal decomposition temperatures above 360℃ as well as the capacity of suppressing lithium dendrite growth.Moreover,the LiFePO_(4)/Li battery assembled with the semi-IPN electrolyte membranes exhibits good cycle performance and admirable reversible specific capacity.This work highlights the obvious advantages of LCs applied to the electrolyte for the advanced solid lithium battery.

Mechanism of back siltation in navigation channel in Dinh An Estuary, Vietnam

The Dinh An Estuary is one of the Nine Dragon estuaries of the Mekong River. An international navigation channel was built in the estuary for vessels traveling from the South China Sea to the southwestern area of Vietnam and then to Phnom Penh, Cambodia. The morphological evolution of the navigation channel is complicated and unstable. The back siltation intensity in the navigation channel has largely increased and been concentrated in the curvature segments of the channel since 1980. In this study, based on simulation results and measured data, five key factors that influence the back siltation in the navigation channel were systematically analyzed. These factors included the increasing elevation gap between the channel and the nearby seabed, the disadvantageous hydrodynamic conditions, sediment transport, mixing of saltwater and freshwater, and wave effects in the navigation channel. It is shown that the back siltation to a large extent results from the low current velocity of the secondary ocean circulation, which often occurs in the curvature segments of the channel. Suspended sediment also settles in the channel due to the decrease of the current velocity and the sediment transport capacity when flow passes through the channel. The changes of hydrodynamic conditions are responsible for the majority of the severe siltation in the curvature segments of the navigation channel.

Mitigating adjacent channel interference in vehicular communication systems

In the last few decades, dedicated wireless channels were specifically allocated to enable the development and implementation of vehicular communication systems. The two main protocol stacks, the WAVE stan- dards proposed by the IEEE in the United States and the ETSI ITS-G5 in Europe, reserved 10 MHz wide channels in the 5.9 GHz spectrum band. Despite the exclusive use of these frequencies for vehicular com- munication purposes, there are still cross channel interference problems that have been widely reported in the literature. In order to mitigate these issues, this paper presents the design of a two-stage FIR low-pass filter, targeting the integration with a digital baseband receiver chain of a custom vehicular communications platform. The filter was tested, evaluated and optimized, with the simulation results proving the effectiveness of the proposed method and the low delay introduced in the overall operation of the receiver chain. 2016 Chongqing University of Posts and Telecommunications. Production and Hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license

Highly Conductive Proton Selectivity Membrane Enabled by Hollow Carbon Sieving Nanospheres for Energy Storage Devices

Ion conductive membranes(ICMs)with highly conductive proton selectivity are of significant importance and greatly desired for energy storage devices.However,it is extremely challenging to construct fast proton-selective transport channels in ICMs.Herein,a membrane with highly conductive proton selectivity was fabricated by incorporating porous carbon sieving nanospheres with a hollow structure(HCSNs)in a polymer matrix.Due to the precise ion sieving ability of the microporous carbon shells and the fast proton transport through their accessible internal cavities,this advanced membrane presented a proton conductivity(0.084 S·cm^(-1))superior to those of a commercial Nation 212(N212)membrane(0.033S·cm^(-1))and a pure polymer membrane(0.049 S·cm^(-1)).The corresponding proton selectivity of the membrane(6.68×10^(5) S·min·cm^(-3))was found to be enhanced by about 5.9-fold and 4.3-fold,respectively,compared with those of the N212 membrane(1.13×10^(5) S·min·cm^(-3))and the pure membrane(1.56×10^(5) S·min·cm^(-3)).Low-field nuclear magnetic resonance(LF-NMR)clearly revealed the fast protonselective transport channels enabled by the HCSNs in the polymeric membrane.The proposed membrane exhibited an outstanding energy efficiency(EE)of 84%and long-term stability over 1400 cycles with a0.065%capacity decay per cycle at 120 mA·cm^(-2) in a typical vanadium flow battery(VFB)system.

Construction of biomimetic proton transport channels in metal-organic framework

Construction of proton transport channels in metal-organic frameworks(MOFs)with simple synthesis processes,high proton conductivities and good performance stabilities has been of great interest for proton exchange membrane fuel cell(PEMFC).Herein,we mimic the proton transport behavior of amino acid residues in bacteriorhodopsin,select UiO-66-COOH as the host,glycine and aspartic acid as the functional guest molecules,and then functionalize the MOF framework with amino acids to obtain biomimetic proton transport channels.This strategy endows UiO-66-COOH-Asp a high proton conductivity of 1.19×10^(-2)S/cm at 70℃and 98%RH,excellent cycle stability of performances and performance durability,which can be comparable to the reported MOFs-based proton conductors.Moreover,the proton conduction mechanism in UiO-66-COOH-Asp is elaborated in detail due to its visual structure,which is also one of the advantages of adopting MOFs as research platform,making it possible to optimize the structure-activity relationship of advanced materials.Notably,this strategy has clear objectives and simple synthesis,which has made certain contributions to both theoretical research and future industrial production of proton conductors.

Potassium sulphate induces resistance of rice against the rootknot nematode Meloidogyne graminicola

Potassium(K),an important nutrient element,can improve the stress resistance/tolerance of crops.The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nematode diseases and increase crop yield.However,data on K_(2)SO_(4)induced rice resistance against the root-knot nematode Meloidogyne graminicola are still lacking.In this work,K_(2)SO_(4)treatment reduced galls and nematodes in rice plants and delayed the development of nematodes.Rather than affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites,such an effect is achieved by rapidly priming hydrogen peroxide(H_(2)O_(2))accumulation and increasing callose deposition.Meanwhile,galls and nematodes in rice roots were more in the potassium channel OsAKT11 and transporter OsHAK5 gene-deficient plants than in wild-type,while the K_(2)SO_(4)-induced resistance showed weaker in the defective plants.In addition,during the process of nematode infection,the expression of jasmonic acid(JA)/ethylene(ET)/brassinolide(BR)signaling pathway-related genes and pathogenesis-related(PR)genes OsPR1 a/OsPR1 b was up-regulated in rice after K_(2)SO_(4)treatment.In conclusion,K_(2)SO_(4)induced rice resistance against M.graminicola.The mechanism of inducing resistance was to prime the basal defense and required the participation of the K^(+)channel and transporter in rice.These laid a foundation for further study on the mechanism of rice defense against nematodes and the rational use of potassium fertilizer on improving rice resistance against nematodes in the field.

Engineering two-dimensional pores in freestanding TiO_2/graphene gel film for high performance lithium ion battery

As the key component of electrochemical energy storage devices, an electrode with superior ions transport pores is the important premise for high electrochemical performance. In this paper, we developed a unique solution process to prepare freestanding TiO_2/graphene hydrogel electrode with tunable density and porous structures. By incorporating room temperature ionic liquids（RTILs）, even upon drying, the non-volatile RTILs that remained in the gel film would preserve the efficient ion transport channels and prevent the electrode from closely stacking, to develop dense yet porous structures. As a result, the dense TiO_2/graphene gel film as an electrode for lithium ion battery displayed a good gravimetric electrochemical performance and more importantly a high volumetric performance.

Molecular coordination-doping engineering enables adjustable ion transport channel based on MOFs-derived UIOLiTF-LLZTO ionic conductor

The inferior ionic conductivity of composite polymer electrolytes(CPEs)caused by grain boundary impedance is one of the critical issues.Adjustable ion transport channels at the molecular level can improve ionic conductivity and lithium-ion transference number.Herein,UIO-66-NSO_(2)CF_(3)LiLi_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(UIOLiTF-LLZTO)ionic conductor derived from metal-organic frameworks(MOFs)was designed by a covalent grafted strategy of trifluoromethylsulfonyl(TF)group on UIOLiTF and a doping process of LLZTO,showing two new lithium-ion transfer channels driven by molecular coordinationdoping engineering.The first channel along UIOLiTF-UIOLiTF was constructed due to the existence of the TF group on UIOLiTF.The second channel along UIOLiTF-LLZTO was constructed due to the direct nanometer contact interface between the opened channel of UIOLiTF and LLZTO.Then TF group acts as“claws”to capture and transfer lithium-ion along the different channels,facilitating improving ionic conductivity and reducing grain boundary impedance.Benefiting from the molecular coordination-doping engineering,UIOLiTF-LLZTO exhibits high ionic conductivity of 9.86×10^(-4)S cm^(-1),a large lithium-ion transference number of 0.79,and a wide electrochemical window of 5.35 V.Meanwhile,all-solid-state Li|UIOLiTF-LLZTO|LiFePO4 batteries show a high specific capacity of 164.5 mAh g^(-1)and 155.6 mAh g^(-1)at 0.2 C and 0.5 C,respectively.Therefore,UIOLiTF-LLZTO demonstrates the way towards the development of MOFs-based CPEs for all-solid-state lithium batteries with high performance.

Stability of Tokamak Equilibrium with Internal Transport Barrier against High n MHD Ballooning Mode

Internal transport barriers （ITBs） are phenomena associated with improved confinement mode of tokamak plasmas. Within the region where the ITB locates, the plasma pressure has a large gradient while the magnetic shear s has a minimum so that within and near the ITB, the absolute value of the shear is very low. Physics involved is plentiful, from the macroscopic （ MHD ） stability, to the suppression of microscopic instabilities thought to be responsible for anomalous transport. The treatment of very low shear also poses some theoretical difficulties.

Ion Transport Mechanism in ClC-Type Channel Protein under Complex Electrostatic Potential

In order to illustrate the ion transport mechanism of chloride channel（Cl C） protein,a type of Cl C protein,Cl C-ec1,from Escherichia coli is embedded into an explicit membranewater system by using software VMD. Then a parallel molecular dynamics（MD） simulation is employed to equilibrate the Cl C-ec1 structure for 27.5 ns at temperature 298.15 K. Based on this equilibrated structure,we compute the channel geometric size variation and electrostatic potential distribution along the channel. Meanwhile,Cl^- transport process is simulated using oriented random walk method under variable external potential. The simulation result shows that Cl^- transport velocity depends on the width of the narrowest channel region. Mutation of negative glutamate E148 can produce positive potential,which is beneficial for Cl^- transport,around external Cl^- binding region in the channel. The simulated current-voltage curves about Cl^- transporting in Cl C-ec1 protein agree with Jayaram＇s experimental results.

Promoted Li+ conduction in PEO-based all-solid-state electrolyte by hydroxyl-modified glass fiber fillers

In the polyoxyethylene(PEO)-based solid-state electrolytes,the low ionic conductivity of lithium ions limits its application in solid-state lithium batteries,so optimizing the conduction path of lithium ions is beneficial to improve the ionic conductivity.In this work,we report the use of hydrothermal carbon nano-sphere(HCS)modified glass fibers(GF)as a functional filler(GF@HCS)to improve the ionic conductivity of PEO composite solidstate electrolytes.The oxygen atoms in the hydroxyl groups on the surface of HCS can be complexed with Li ions as its transport sites,which means that it can promote the longdistance transport of Li ions along the glass fiber surface.With addition of 2 wt%GF@HCS fillers,the degree of crystallinity of PEO composite solid-state electrolyte is the smallest,and the ionic conductivity is significantly increased from 8.9×10^(-5) to 4.4×10^(-4) S·cm^(-1) at 60℃.Moreover,the PEO composite solid-state electrolyte exhibits better lithium-metal interface stability in symmetric lithium batteries and superior rate performance in LiFePO4 solid-state batteries.

Calcium signaling in plant mineral nutrition:From uptake to transport

Plant mineral nutrition is essential for crop yields and human health.However,the uneven distribution of mineral elements over time and space leads to a lack or excess of available mineral elements in plants.Among the essential nutrients,calcium(Ca^(2+))stands out as a prominent second messenger that plays crucial roles in response to extracellular stimuli in all eukaryotes.Distinct Ca^(2+)signatures with unique parameters are induced by different stresses and deciphered by various Ca^(2+)sensors.Recent research on the participation of Ca^(2+)signaling in regulation of mineral elements has made great progress.In this review,we focus on the impact of Ca^(2+)signaling on plant mineral uptake and detoxification.Specifically,we emphasize the significance of Ca^(2+)signaling for regulation of plant mineral nutrition and delve into key points and novel avenues for future investigations,aiming to offer new insights into plant ion homeostasis.

NUMERICAL TEST OF AN EARLY-SUMMER EXPLOSIVE CYCLONE EVENT IN EAST ASIA

A series of ten numerical tests are carried out using smoothing techniques in the PSU/NACR mesoscale model MM5 initial field in order to study the development reasons of a pre-summer uncommon explosive event which took place in East Asia from 1—2 June.1993.The integration fields are compared with that of original results obtained by non-smoothed initial field.The results show that:(1)After the northern trough is smoothed,its corresponding cold air can not move downward and southward.Only a weak cyclone system forms south of 25°N after 24 h integration. (2)After the southern strong moisture transportation channel is smoothed,the northem trough system can only form a weak trough along the east coast of China after 24 h integration.(3)These two separate low trough systems in the southern and northern jet systems,with strong warm moisture transportation channel and cold air respectively,are both necessary for explosive cyclone development.In such an unfavorable season and location for explosive cyclone to take place,only after these two low troughs merged into a strong low vortex can the surface cyclone he developed explosively.Both the northern trough system and the southern moisture transportation channel are all indispensable for the explosive cyclone development.This explosive cyclone event is the result of the interaction of northern and southern systems.

Electrolyte-mediated dense integration of graphene-MXene films for high volumetric capacitance flexible supercapacitors

High conductivity two-dimensional(2D)materials have been proved to be potential electrode materials for flexible supercapacitors because of its outstanding chemical and physical properties.However,electrodes based on 2D materials always suffer from limited electrolyte-accessible surface due to the restacking of the 2D sheets,hindering the full utilization of their surface area.In this regard,an electrolyte-mediated method is used to integrate dense structure reduced graphene oxide/MXene(RGM)-electrolyte composite films.In such composite films,reduced graphene oxide(RGO)and MXene sheets are controllable assembly in compact layered structure with electrolyte filled between the layers.The electrolyte layer between RGO and MXene sheets forms continuous ion transport channels in the composite films.Therefore,the RGM-electrolyte composite films can be used directly as self-supporting electrodes for supercapacitors without additional conductive agents and binders.As a result,the composite films demonstrate enhanced volumetric specific capacity,improved volumetric energy density and higher power density compared with both pure RGO electrode and porous composite electrode prepared by traditional methods.Specifically,when the mass ratio of MXene is 30%,the electrode delivers a volumetric specific capacity of 454.9 F·cm^(−3) with a high energy density of 39.4 Wh·L^(−1).More importantly,supercapacitors based on the composite films exhibit good flexibility electrochemical performance.The investigation provides a new approach to synthesize dense structure films based on 2D materials for application in high volumetric capacitance flexible supercapacitors.

A benzo[ghi]-perylene triimide based double-cable conjugated polymer for single-component organic solar cells

Single-component organic solar cells(SCOSCs)with high stability and simplified fabrication process are supposed to accelerate the commercialization of organic photovoltaics.However,the types of photo-active materials and photovoltaic performance of SCOSCs are still far lagging behind the bulk-heterojunction type organic solar cells(BHJ OSCs).It is still an arduous task to introduce new photo-active materials into SCOSCs,aiming to improve the efficiencies of SCOSCs.One feasible way is to construct double-cable polymers with new structures and tune conformation,morphology and mobility for the improvement in power conversion efficiencies(PCEs).Hence,in this work,we constructed a new double-cable polymer PBTT-BPTI by introducing fused core 5,7-dibromo-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c’]dithiophene-4,8-dione(TTDO)into the main backbone and benzo[ghi]-perylene triimide(BPTI)unit into the side chain.Both of the two units show strong electron-withdrawing property,which are expected to broaden absorption spectra and enhance intermolecular interaction.The double-cable polymer exhibited a broad absorption in the range of 300-700 nm with an optical band gap(E_(g))of 1.79 eV.The PCE of PBTT-BPTI-based SCOSCs was 2.15%,which may be limited by the unconstructed efficient electron transporting channels.

Experimental Investigations on Fiber Motion within Rotor Spinning Unit

An experimental platform is constructed to photograph fibers＇ motion within rotor spinning unit, which is mainly composed of a transparent rotor and a transport channel based on the similarity theory. The fibers will stretch and gather into a fiber bundle in the transport channel. The velocity of fibers is increasing along the inlet to the outlet of the transport channel, and the fibers＇ maximum velocity appears at the outlet of transport channel. The straightness of the fiber bundle is related to the convergence degree of the transport channel, and the greater the convergence degree is, the straighter the fiber bundle stretches. The results will provide a useful insight to the yam-forming mechanism of rotor spinning.