Comparative review of corrosion-resistant coatings on metal bipolar plates of proton exchange membrane fuel cells

In the realm of proton exchange membrane fuel cells(PEMFCs),the bipolar plates(BPs)are indispensable and serve pivotal roles in distributing reactant gases,collecting current,facilitating product water removal,and cooling the stack.Metal BPs,characterized by outstanding manufacturability,cost-effectiveness,higher power density,and mechanical strength,are emerging as viable alternatives to traditional graphite BPs.The foremost challenge for metal BPs lies in enhancing their corrosion resistance and conductivity under acidic conditions,necessitating the application of various coatings on their surfaces to ensure superior performance.This review summarizes and compares recent advancements in the research of eight distinct types of coatings for BPs in PEMFCs,including noble metal,carbide,ni-tride,and amorphous carbon(a-C)/metal compound composite coatings.The various challenges encountered in the manufacturing and fu-ture application of these coatings are also delineated.

Polypyrrole-coated triple-layer yolk-shell Fe_(2)O_(3)anode materials with their superior overall performance in lithium-ion batteries

Iron oxide(Fe_(2)O_(3))emerges as a highly attractive anode candidate among rapidly expanding energy storage market.Nonethe-less,its considerable volume changes during cycling as an electrode material result in a vast reduced battery cycle life.In this work,an ap-proach is pioneered for preparing high-performance Fe_(2)O_(3)anode materials,by innovatively synthesizing a triple-layer yolk-shell Fe_(2)O_(3)uniformly coated with a conductive polypyrrole(Ppy)layer(Fe_(2)O_(3)@Ppy-TLY).The uniform polypyrrole coating introduces more reac-tion sites and adsorption sites,and maintains structure stability through charge-discharge process.In the uses as lithium-ion battery elec-trodes,Fe_(2)O_(3)@Ppy-TLY demonstrates high reversible specific capacity(maintaining a discharge capacity of 1375.11 mAh·g^(−1)after 500 cycles at 1 C),exceptional cycling stability(retaining the steady charge-discharge performance at 544.33 mAh·g^(−1)after 6000 ultrafast charge-discharge cycles at a 10 C current density),and outstanding high current charge-discharge performance(retaining a reversible ca-pacity of 156.75 mAh·g^(−1)after 10000 cycles at 15 C),thereby exhibiting superior lithium storage performance.This work introduces in-novative advancements for Fe_(2)O_(3)anode design,aiming to enhance its performance in energy storage fields.

An Asymmetric Galactic Stellar Disk Traced by OB-type Stars from LAMOST DR7

Using 9943 OB-type stars from LAMOST DR7 in the solar neighborhood,we fit the vertical stellar density profile with the model including a single exponential distribution at different positions(R,Φ).The distributions of the scale heights and scale length show that the young disk traced by the OB-type stars is not axisymmetric.The scale length decreases versus the azimuthal angleΦ,i.e.,from.■kpc withΦ=-3°to■kpc withΦ=9°.Meanwhile we find signal of non-symmetry in the distribution of the scale height of the north and south of the disk plane.The scale height in the north side shows signal of flaring of the disk,while that of the south disk stays almost constant around h_(s)=130 pc.The distribution of the displaceeent of the disk plane Z_(0)also shows variance versus the azimuthal angleΦ,which displays significant differences with the warp model constrained by the Cepheid stars.We also test different values for the position of the Sun,and the distance between the Sun and the Galactic center affects the scale heights and the displacement of the disk significantly,but that does not change our conclusion that the disk is not axisymmetric.

铁改性酚醛树脂的合成与结构表征

通过配位反应在热固性酚醛树脂中引入三价铁离子,合成了铁改性酚醛树脂。通过红外光谱仪、X射线光电子能谱仪以及利用电导率测定配位数的方法表征了铁改性酚醛树脂的结构,分析得到三价铁离子与酚醛树脂形成六配位的结构,4个氧原子来自亚氨基二乙酸的羧酸基,2个氧原子来自游离的酚羟基。与普通树脂相比,铁改性酚醛树脂的固含量和残炭率明显提高,分别达到89. 16%和51. 41%;通过热重分析表明,铁改性酚醛树脂的耐热性能明显提高。

Rearrangement on surface structures by boride to enhanced cycle stability for LiNi0.80Co0.15Al0.05O2 cathode in lithium ion batteries

The side reaction between the active material and liquid-electrolyte cause structural damage and particle pulverization is one of the important factors leading to the capacity decay of LiNi0.80Co0.15Al0.05O2(NCA)materials in Li ion batteries(LIBs).Surface modification is an effective strategy for NCA cathodes,which could alleviate the degradation associated with surface processes.Herein,a surface structure rearrangement of NCA cathode secondary particles was reported by in-situ forming a solid electrolyte LiBO2.The LiBO2 is beneficial for alleviating the stress during charge/discharge process,thereby slowing down the rate of cracks formation in the secondary particles,which facilitates the Li+de-intercalation as well as prevents penetration of the liquid-electrolyte into the interior of the particles.As a result,the surface structure rearrangement NCA(RS-NCA)delivers a high discharge capacity of 202.5 m Ah g^-1 at 0.1 C,and exhibits excellent cycle stability with discharge capacity retaining 148 m Ah g^-1 after 200 cycles at 2 C.This surface structure rearrangement approach provides a new viewpoint in designing high-performance high-voltage LIBs.

Cancer risk in relatives of BRCA1/2 pathogenic variant carriers in a large series of unselected patients with breast cancer

Objective:The spectrum and risk of cancer in relatives of BRCA1/2 pathogenic variant carriers in the Chinese population have not been established.Methods:A family history of cancer in 9903 unselected breast cancer patients was retrospectively analyzed.BRCA1/2 status was determined for all patients and relative risks(RRs)were calculated to evaluate cancer risk in relatives of the patients.Results:The incidences of breast cancer in female relatives of BRCA1 carriers,BRCA2 carriers,and non-carriers were 33.0%,32.2%,and 7.7%,respectively.The corresponding incidences of ovarian cancer were 11.5%,2.4%,and 0.5%,respectively.The incidences of pancreatic cancer in male relatives of BRCA1 carriers,BRCA2 carriers,and non-carriers were 1.4%,2.7%,and 0.6%,respectively.The corresponding incidences of prostate cancer were 1.0%,2.1%,and 0.4%,respectively.The risks of breast and ovarian cancers in female relatives of BRCA1 and BRCA2 carriers were significantly higher than female relatives of non-carriers(BRCA1:RR=4.29,P<0.001 and RR=21.95,P<0.001;BRCA2:RR=4.19,P<0.001 and RR=4.65,P<0.001,respectively).Additionally,higher risks of pancreatic and prostate cancers were noted in male relatives of BRCA2 carriers than non-carriers(RR=4.34,P=0.001 and RR=4.86,P=0.001,respectively).Conclusions:Female relatives of BRCA1 and BRCA2 carriers are at increased risk for breast and ovarian cancers,and male relatives of BRCA2 carriers are at increased risk for pancreatic and prostate cancers.

An Enhanced Sensorless Control Scheme for PMSM Drives Considering Self-inductance Asymmetry

Inductance asymmetry,which is brought by inherent asymmetric parameters,manufacture tolerance,winding fault,cables with unequal lengths,etc.,of permanent-magnet synchronous machines(PMSMs)can cause current harmonics and inaccurate position estimation.This paper proposes an enhanced fundamental model based sensorless control strategy for PMSMs with asymmetric inductances.The proportional-integral-resonant current regulator is introduced to reduce the second-order harmonics of currents,but there are still negative sequence components in the estimated back-electromotive forces(EMFs),which can cause the position estimated error.Differing from conventional methods in which negative sequences are filtered out before the phase-locked loop(PLL)module,the proposed method directly applies the estimated back-EMF with negative sequences as the reference input of PLL.An improved PLL with a bi-quad filter is proposed to attenuate the arising second harmonic position error and heighten the steady-state accuracy.Then,this position error is used for asymmetric inductance identification and its result is utilized to update the observer model.Furthermore,the dynamic performance is improved by the output limitation on the bi-quad filter as well as the implementation of a fast-locking technique in the PLL.The effectiveness of the proposed scheme is verified by experimental results.

Research of an Efficient LED Lighting Driver Based on Boost-Buck Converter

Boost-Buck converter is widely used in LED lighting drivers. In this paper, Boost-Buck main circuit related characteristics are firstly discussed, and then a new Boost-Buck high power efficient double loop control strategy is built by adopting error amplifier and integrator control method. It is demonstrated that the new system has many advantages such as high efficiency, fast response, strong anti-interference, good stability after analyses and simulations of its working dynamic characteristics.

Corrigendum to“Rearrangement on surface structures by boride to enhanced cycle stability for LiNi_(0.80)Co_(0.15)Al_(0.0)5O_(2) cathode in lithium ion batteries”[J.Energy.Chem.45(2020)110-118]

The authors regret that the printed version of the above article contained some errors.The funding number in acknowledgments of this paper was incorrectly marked,and we hope to correct it.We thank the National Natural Science Foundation of China(51764048,51703118 and 51474191),Yunnan Province Thousand Youth Talents Plan,the Application Basis Research Project of Yunnan Province Science and Technology Department(2017FD144)and Key Natural Science Foundation of Yunnan Province China(2018FA28)for providing the financial support.

CEPC Technical Design Report

The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.

Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders

Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders.These people store fat in subcutaneous adipose tissue(SAT)rather than in visceral adipose tissue(VAT).However,the molecules participating in this specific scenario remain elusive.Rab18,a lipid droplet(LD)-associated protein,mediates the contact between the endoplasmic reticulum(ER)and LDs to facilitate LD growth and maturation.In the present study,we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice.Rab18 adipocyte-specific knockout(Rab18 AKO)mice had a decreased volume ratio of SAT to VAT compared with wildtype mice.When subjected to high-fat diet(HFD),Rab18 AKO mice had increased ER stress and inflammation,reduced adiponectin,and decreased triacylglycerol(TAG)accumulation in SAT.In contrast,TAG accumulation in VAT,brown adipose tissue(BAT)or liver of Rab18AKO mice had a moderate increase without ER stress stimulation.Rab18 AKO mice developed insulin resistance and systematic inflammation.Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT,similar to the counterpart mice.Furthermore,Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress,indicating the involvement of Rab18 in alleviating lipid toxicity.Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT.In conclusion,our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.

Three-dimensional porous In_(2)O_(3) arrays for self-powered transparent solar-blind photodetectors with high responsivity and excellent spectral selectivity

Transparent solar-blind ultraviolet photodetectors(SBUV PDs)have extensive applications in versatile scenarios,such as optical communication.However,it is still challenging to simultaneously achieve high responsivity,high transparency,and satisfying self-powered capability.Here,we demonstrated high-performance,transparent,and self-powered photoelectrochemical-type(PEC)SBUV PDs based on vertically grown ultrathin In_(2)O_(3) nanosheet arrays(NAs)with a three-dimensional(3D)porous structure.The 3D porous structure simultaneously improves the transmittance in the visible light region,accelerates interfacial reaction kinetics,and promotes photogenerated carrier transport.The performance of In_(2)O_(3) NAs photoanodes exceeds most reported self-powered PEC SBUV PDs,exhibiting a high transmittance of approximately 80%in the visible light region,a high responsivity of 86.15 mA/W for 254 nm light irradiation,a fast response speed of 15/18 ms,and good multicycle stability.The In_(2)O_(3) NAs also show excellent spectral selectivity with an ultrahigh solar-blind rejection ratio of 1319.30,attributed to the quantum confinement effect induced by the ultrathin feature(2-3 nm).Furthermore,In_(2)O_(3) NAs photoanodes show good capability in underwater optical communication.Our work demonstrated that a 3D porous structure is a powerful strategy to synchronously achieve high responsivity and transparency and provides a new perspective for designing high-performance,transparent,and self-powered PEC SBUV PDs.

Centrifuge study on behavior of raft foundation after tunnelling in soft clay

Ground losses due to tunneling would induce settlement of nearby raft foundations.To study the change in behavior of the raft foundations over time due to tunnel excavation in soft clay,a series of centrifuge model tests were conducted.The results reveal that the raft stiffness has a significant influence on the development of the gap between the raft and the ground.The width of the gap beneath the flexible foundation would increase over time,leading to a further increase in tensile strain after excavation,whereas the gap for raft foundations with a large stiffness would reduce with time,causing a gradual decrease in tensile strain.The modification factor(MF)design approach is also evaluated with the test results and demonstrates that the MF design approach would underestimate the tensile strain of the flexible raft and provide a relatively conservative prediction for larger stiffnesses.

Bioinspired integrated triboelectric electronic tongue

An electronic tongue(E-tongue)comprises a series of sensors that simulate human perception of taste and embedded artificial intelligence(AI)for data analysis and recognition.Traditional E-tongues based on electrochemical methods suffer from a bulky size and require larger sample volumes and extra power sources,limiting their applications in in vivo medical diagnosis and analytical chemistry.Inspired by the mechanics of the human tongue,triboelectric components have been incorporated into E-tongue platforms to overcome these limitations.In this study,an integrated multichannel triboelectric bioinspired E-tongue(TBIET)device was developed on a single glass slide chip to improve the device’s taste classification accuracy by utilizing numerous sensory signals.The detection capability of the TBIET was further validated using various test samples,including representative human body,environmental,and beverage samples.The TBIET achieved a remarkably high classification accuracy.For instance,chemical solutions showed 100%identification accuracy,environmental samples reached 98.3%accuracy,and four typical teas demonstrated 97.0%accuracy.Additionally,the classification accuracy of NaCl solutions with five different concentrations reached 96.9%.The innovative TBIET exhibits a remarkable capacity to detect and analyze droplets with ultrahigh sensitivity to their electrical properties.Moreover,it offers a high degree of reliability in accurately detecting and analyzing various liquid samples within a short timeframe.The development of a self-powered portable triboelectric E-tongue prototype is a notable advancement in the field and is one that can greatly enhance the feasibility of rapid on-site detection of liquid samples in various settings.

Non-destructive 3D geometric modeling of maize root-stubble in-situ via X-ray computed tomography

No-tillage seeding has become an important approach to improve crop productivity,which needs colters of high performance to cut the root-stubble-soil composite.However,the difficulty of maize root-stubbles three-dimensional(3D)modeling hinders finite element(FE)simulation to improve development efficiency of such colters because of maize root system complexity and opaque nature of the soil.Fortunately,the non-destructive 3D geometric model of the maize root-stubble in-situ can be established via X-ray computed tomography(CT)following by a systematic procedure.The whole procedure includes CT scanning of the maize root-stubble-soil composite sample,image reconstruction via filtered back-projection(FBP)with the Hanning filter,segmentation of root-stubble via a variational level set method,and post-processing via morphological operations.The 3D reconstruction model of the maize root-stubble in-situ presents a complete,complex and in-situ geometrical morphology,which cannot be realized via other methods,including the destructive modelling after washing via CT.This study is the first to build a 3D geometric model of a maize root-stubble in-situ via CT,which opens up new possibilities for simulation of root-stubble-soil cutting using FEM,and much other research related to plant root-stubbles.

Piezoelectric pump with flexible venous valves for active cell transmission

The development of organ-on-a-chip systems demands high requirements for adequate micro-pump performance,which needs excellent performance and effective transport of active cells.In this study,we designed a piezoelectric pump with a flexible venous valve inspired by that of humans.Performance test of the proposed pump with deionized water as the transmission medium shows a maximum output flow rate of 14.95 mL/min when the input voltage is 100 V,and the pump can transfer aqueous solutions of glycerol with a viscosity of 10.8 mPa·s.Cell survival rate can reach 97.22%with a yeast cell culture solution as the transmission medium.A computational model of the electric-solid-liquid multi-physical field coupling of the piezoelectric pump with a flexible venous valve is established,and simulation results are consistent with experimental results.The proposed pump can help to construct the circulating organ-on-a-chip system,and the simple structure and portable application can enrich the design of microfluidic systems.In addition,the multi-physical field coupling computational model established for the proposed piezoelectric pump can provide an in-depth study of the characteristics of the flow field,facilitating the optimal design of the micro-pump and providing a reference for the further study of active cell transport in organ-on-a-chip systems.

Detecting molecular vibrational modes of side chains and endpoints in nanoscale proteins with graphene plasmon

Monitoring the chemical and structural changes in protein side chains and endpoints by infrared(IR)spectroscopy is important for studying the chemical reaction and physical adsorption process of proteins.However,the detection of side chains and endpoints in nanoscale proteins is still challenging due to its weak IR response.Here,by designing a double layered graphene plasmon sensor on MgF2/Si substrate in the IR fingerprint region,we detect the vibrational modes in side chains and endpoints(1397 cm^-1 and 1458 cm^-1)of monolayer protein.The sensor could be applied on biochemistry to investigate the physical and chemical reaction of biomolecules.

Role of let-7 family in the invasion and metastasis of osteosarcoma

To the Editor:Osteosarcoma(OS),a disease seriously endangering the health of young people,is the eighth most common primary malignant bone tumor affecting children and adolescents.Typically occurring in the metaphysis of long tubular bone,OS develops from mesenchymal cells and accounts for 20%of primary bone tumors.About 70%to 80%of patients are 8 to 9 years.

Amplitude gradient-based metasurfaces for off-chip terahertz wavefront shaping

Metasurfaces provide an effective technology platform for manipulating electromagnetic waves,and the existing design methods all highlight the importance of creating a gradient in the output phase across light scattering units.However,in the emerging research subfield of meta-waveguides where a metasurface is driven by guided modes,this phase gradient-oriented approach can only provide a very limited emission aperture,significantly affecting the application potential of such meta-waveguides.In this work,we propose a new design approach that exploits the difference between meta-atoms in their light scattering amplitude.By balancing this amplitude gradient in the meta-atoms against the intensity decay in the energy-feeding waveguide,a large effective aperture can be obtained.Based on this new design approach,three different wavefront shaping functionalities are numerically demonstrated here on multiple devices in the terahertz regime.They include beam expanders that radiate a plane wave,where the beam width can increase by more than 900 times as compared to the guided wave.They also include a metalens that generates a Bessel-beam focus with a width 0.59 times the wavelength,and vortex beam generators that emit light with a tunable topological charge that can reach-30.This amplitude gradient design approach could benefit a variety of off-chip light shaping applications such as remote sensing and 6G wireless communications.

TaNRAMP3 is essential for manganese transport in Triticum aestivum

Manganese(Mn)is an essential trace element for almost all living organisms.In plants,Mn deficiency,which is occurs in calcareous soils or alkaline soils,severely limiting crop yields.However,the potential mechanism of Mn transport in Triticum aestivum is still obscure.Here,we found that TaNRAMP3,a member of the naturally resistant macrophage protein(NRAMP)family in Triticum aestivum,is located in the plasma membrane of protoplasts and functions as an influx transporter for Mn in yeast(Δsmf1).The expression of TaNRAMP3 was induced under Mn-deficiency condi-tions.Furthermore,TaNRAMP3-RNAi plants exhibited a sensitive phenotype,while transgenic plants overexpressing TaNRAMP3 showed a tolerant phenotype.In addition,TaNRAMP3 rescued the sensitive phenotype of Arabidopsis nramp1 mutant under Mn deficiency condition.In summary,our study reveals the key role of TaNRAMP3 in Mn transport in Triticum aestivum,allowing it to adapt to Mn-deficiency stress.These findings provide new insights for the cultivation of Mn-deficiency tolerant wheat varieties.