High-Temperature Superconductivity in La_(3)Ni_(2)O_(7)

Motivated by the recent discovery of high-temperature superconductivity in bilayer La_(3)Ni_(2)O_(7) under pressure,we study its electronic properties and superconductivity due to strong electron correlation.Using the inversion symmetry,we decouple the low-energy electronic structure into block-diagonal symmetric and antisymmetric sectors.It is found that the antisymmetric sector can be reduced to a one-band system near half filling,while the symmetric bands occupied by about two electrons are heavily overdoped individually.Using the strong coupling mean field theory,we obtain strong superconducting pairing with B_(1g)symmetry in the antisymmetric sector.We propose that due to the spin-orbital exchange coupling between the two sectors,B_(1g)pairing is induced in the symmetric bands,which in turn boosts the pairing gap in the antisymmetric band and enhances the high-temperature superconductivity with a congruent d-wave symmetry in pressurized La_(3)Ni_(2)O_(7).

Recent progress about transmission electron microscopy characterizations on lithium-ion batteries

With the rapid development of portable electronics,new energy vehicles,and smart grids,ion batteries are becoming one of the most widely used energy storage devices,while the safety concern of ion batteries has always been an urgent problem to be solved.To develop a safety-guaranteed battery,the characterization of the internal structure is indispensable,where electron microscopy plays a crucial role.Based on this,this paper summarizes the application of transmission electron microscopy(TEM)in battery safety,further concludes and analyzes the aspects of dendrite growth and solid electrolyte interface(SEI)formation that affect the safety of ion batteries,and emphasizes the importance of electron microscopy in battery safety research and the potential of these techniques to promote the future development of this field.These advanced electron microscopy techniques and their prospects are also discussed.

热氧老化对聚醚醚酮结构与性能的影响

聚醚醚酮(PEEK)作为工程材料广泛应用于多个领域,研究其热氧老化规律对其材料服役优化具有重要意义。采用傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、X射线衍射、差示扫描量热和万能拉力机等测试了PEEK片在310℃高温环境中热氧老化不同时间后化学结构及性能的变化。结果表明,在实验老化时间范围内,FT-IR谱图中未出现新的红外吸收峰;XPS谱图显示样品表面形成了氧化产物,且老化168 h的氧化程度达到最大;样品的结晶温度、熔融焓及结晶度均随着热老化时间的延长而减小,在老化504 h后结晶度降为9.7%;老化样品的断裂伸长率随着热老化时间的延长而减小,断裂应力在热老化96 h范围内呈上升趋势,随后逐渐降低。

Research progress in electrospinning engineering for all-solid-state electrolytes of lithium metal batteries

Owing to safety issue and low energy density of liquid lithium-ion batteries(LIBs),all-solid-state lithium metal batteries(ASLMBs)with unique all-solid-state electrolytes(SEs)have attracted wide attentions.This arises mainly from the advantages of the SEs in the suppression of lithium dendrite growth,long cycle life,and broad working temperature range,showing huge potential applications in electronic devices,electric vehicles,smart grids,and biomedical devices.However,SEs suffer from low lithiumion conductivity and low mechanical integrity,slowing down the development of practical ASLMBs.Nanostructure engineering is of great efficiency in tuning the structure and composition of the SEs with improved lithium-ion conductivity and mechanical integrity.Among various available technologies for nanostructure engineering,electrospinning is a promising technique because of its simple operation,cost-effectiveness,and efficient integration with different components.In this review,we will first give a simple description of the electrospinning process.Then,the use of electrospinning technique in the synthesis of various SEs is summarized,for example,organic nanofibrous matrix,organic/inorganic nanofibrous matrix,and inorganic nanofibrous matrix combined with other components.The current development of the advanced architectures of SEs through electrospinning technology is also presented to provide references and ideas for designing high-performance ASLMBs.Finally,an outlook and further challenges in the preparation of advanced SEs for ASLMBs through electrospinning engineering are given.

Low-content Pt-triggered the optimized d-band center of Rh metallene for energy-saving hydrogen production coupled with hydrazine degradation

Utilizing the hydrazine-assisted water electrolysis for energy-efficient hydrogen production shows a promising application, which relies on the development and design of efficient bifunctional electrocatalysts. Herein, we reported a low-content Pt-doped Rh metallene(Pt-Rhene) for hydrazine-assisted water electrolysis towards energy-saving hydrogen(H_(2)) production, where the ultrathin metallene is constructed to provide enough favorable active sites for catalysis and improve atom utilization.Additionally, the synergistic effect between Rh and Pt can optimize the electronic structure of Rh for improving the intrinsic activity. Therefore, the required overpotential of Pt-Rhene is only 37 mV to reach a current density of-10 mA cm^(-2) in the hydrogen evolution reaction(HER), and the Pt-Rhene exhibits a required overpotential of only 11 mV to reach a current density of 10 mA cm^(-2) in the hydrazine oxidation reaction(HzOR). With the constructed HER-HzOR two-electrode system, the Pt-Rhene electrodes exhibit an extremely low voltage(0.06/0.19/0.28 V) to achieve current densities of 10/50/100 mA cm^(-2) for energy-saving H_(2) production, which greatly reduces the electrolysis energy consumption. Moreover,DFT calculations further demonstrate that the introduction of Pt modulates the electronic structure of Rh and optimizes the d-band center, thus enhancing the adsorption and desorption of reactant/intermediates in the electrocatalytic reaction.

Direct observation of the scaling relation between density of states and pairing gap in a dirty superconductor

Theories and experiments on dirty superconductors are complex but important in terms of both theoretical fundamentals and practical applications.These activities are even more challenging when magnetic fields are present because the field distribution,electron density of states,and superconducting pairing potentials become nonuniform.Here,we present tunneling microspectroscopic experiments on NbC single crystals and demonstrate that NbC is a homogeneous dirty superconductor.When applying magnetic fields to the samples,we found that the zero-energy local density of states and the pairing energy gap followed the explicit scaling relation proposed by de Gennes for homogeneous dirty superconductors in high magnetic fields.More significantly,our experimental findings indicate that the validity of the scaling relation extends to magnetic field strengths far below the upper critical field,calling for a new nonperturbative understanding of this fundamental property in dirty superconductors.On the practical side,we used the observed scaling relation to derive a simple and straightforward experimental scheme for estimating the superconducting coherence length of a dirty superconductor in magnetic fields.

A 40 Gb/s SerDes Transceiver Chip with Controller and PHY in a 65 nm CMOS Technology

A 40 Gb/s full serializer and deserializer (SerDes) transceiver with controller and physical layer (PHY) is presented.The controller mainly contains protocol transmission, forward error correction and user layer build-in self-test (BIST).The physical coding sub-layer (PCS) provides the functions of 64/66 encoder/decoder, PHY BIST, and polarity control.In the physical medium attachment (PMA), both transmitter (TX) and receiver (RX) adopt quarter-rate architecture to relax the timing constraint and reduce power dissipation.The receiver utilizes the phase interpolator (PI) based clock and data recovery (CDR) with bang-bang phase detector (BBPD) to extract the synchronic clock for retiming and de-multiplexing.The multiple-MUX based 4-tap FFE and a two-stage cascade CTLE are employed to mitigate the inter-symbol interference (ISI).In addition, a proposed 4∶1 MUX is used to improve the output jitter performance and reduce the power consumption.Fabricated in a 65 nm CMOS technology, the full transceiver consumes 890 mW at 40 Gb/s and occupies 12 mm 2 .The measurement results show that this transceiver can achieve bit error rate (BER)< 10 -12 after a 15.3 dB loss channel at 20 GHz.

A High-Order Scheme for Fractional Ordinary Differential Equations with the Caputo-Fabrizio Derivative

In this paper, we consider numerical solutions of fractional ordinary diferential equations with the Caputo-Fabrizio derivative, and construct and analyze a high-order time-stepping scheme for this equation. The proposed method makes use of quadratic interpolation function in sub-intervals, which allows to produce fourth-order convergence. A rigorous stability and convergence analysis of the proposed scheme is given. A series of numerical examples are presented to validate the theoretical claims. Traditionally a scheme having fourth-order convergence could only be obtained by using block-by-block technique. The advantage of our scheme is that the solution can be obtained step by step, which is cheaper than a block-by-block-based approach.

Ensifer adhaerens CAS22-03发酵工艺优化及D-p-HPG的酶法制备

为了研究Ensifer adhaerens CAS22-03来源的D-海因酶(D-Hase)与N-氨甲酰水解酶(D-Case)表达活性的影响因素,提高Ensifer adhaerens CAS22-03全细胞催化制备D-对羟基苯甘氨酸(D-p-HPG)的效率,本工作采用单因素试验和正交试验优化了Ensifer adhaerens CAS22-03发酵培养基的碳源、氮源,建立了Ensifer adhaerens CAS22-03的分批补料发酵工艺,分析了DHase和D-Case的酶学特性,开发了基于Ensifer adhaerens CAS22-03全细胞催化的D-p-HPG酶促生产工艺。结果表明,Ensifer adhaerens CAS22-03的最适碳源和氮源为蔗糖和酵母浸粉,分批补料发酵过程中,D-Hase和D-Case的活性高达243.6和55.8 U/g,分别提高了56.9%和46.4%。D-Hase和D-Case的最适反应温度均为45℃,最适反应pH分别为9和8。Ensifer adhaerens CAS22-03全细胞催化制备D-p-HPG的过程中,当底物浓度为40 g/L、酶用量为底物:菌体=5:1时,40℃,200 r/min条件下反应10 h,底物转化率达到95%以上,本工作的研究结果为D-p-HPG的工业酶法生产奠定了基础。

Construction of functional neural network tissue combining CBD-NT3-modified linear-ordered collagen scaffold and TrkC-modified iPSC-derived neural stem cells for spinal cord injury repair

Induced pluripotent stem cells(iPSCs)can be personalized and differentiated into neural stem cells(NSCs),thereby effectively providing a source of transplanted cells for spinal cord injury(SCI).To further improve the repair efficiency of SCI,we designed a functional neural network tissue based on TrkC-modified iPSC-derived NSCs and a CBD-NT3-modified linear-ordered collagen scaffold(LOCS).We confirmed that transplantation of this tissue regenerated neurons and synapses,improved the microenvironment of the injured area,enhanced remodeling of the extracellular matrix,and promoted functional recovery of the hind limbs in a rat SCI model with complete transection.RNA sequencing and metabolomic analyses also confirmed the repair effect of this tissue from multiple perspectives and revealed its potential mechanism for treating SCI.Together,we constructed a functional neural network tissue using human iPSCs-derived NSCs as seed cells based on the interaction of receptors and ligands for the first time.This tissue can effectively improve the therapeutic effect of SCI,thus confirming the feasibility of human iPSCs-derived NSCs and LOCS for SCI repair and providing a valuable direction for SCI research.

Dynamic 3D holographic projection of vectorial images with a multimode fiber

An optical multimode fiber(MMF)is capable of delivering structured light modes or complex images with high flexibility.Here,we present a holographic approach to enable the MMF as a 3D holographic projector with the capability of complete polarization control.By harnessing the strong coupling of the spatial and polarization degrees of freedom of light propagating through MMFs,our approach realizes active control of the output intensity and polarization in 3D space by shaping only the wavefront of the incident light.In this manner,we demonstrate MMF-based holographic projection of vectorial images on multiple planes via a phase-only hologram.Particularly,dynamic projection of polarization-multiplexed grayscale images is presented with an averaged Pearson correlation coefficient of up to 0.91.Our work is expected to benefit fiber-based holographic displays,data transmission,optical imaging,and manipulation.

多带笼目超导体CsV_(3)Sb_(5)衍生体系的可调磁通涡旋束缚态

Vortices and bound states offer an effective means of comprehending the electronic properties of superconductors.Recently,surface-dependent vortex core states have been observed in the newly discovered kagome superconductors CsV_(3)Sb_(5).Although the spatial distribution of the sharp zero energy conductance peak appears similar to Majorana bound states arising from the superconducting Dirac surface states,its origin remains elusive.In this study,we present observations of tunable vortex bound states(VBSs)in two chemically-doped kagome superconductors Cs(V_(1-x)Tr_(x))_(3)Sb_(5)(Tr=Ta or Ti),using low-temperature scanning tunneling microscopy/spectroscopy.The CsV_(3)Sb_(5)-derived kagome superconductors exhibit full-gap-pairing superconductivity accompanied by the absence of long-range charge orders,in contrast to pristine CsV_(3)Sb_(5).Zero-energy conductance maps demonstrate a field-driven continuous reorientation transition of the vortex lattice,suggesting multiband superconductivity.The Ta-doped CsV_(3)Sb_(5)displays the conventional cross-shaped spatial evolution of Caroli-de Gennes-Matricon bound states,while the Tidoped CsV_(3)Sb_(5)exhibits a sharp,non-split zero-bias conductance peak(ZBCP)that persists over a long distance across the vortex.The spatial evolution of the non-split ZBCP is robust against surface effects and external magnetic field but is related to the doping concentrations.Our study reveals the tunable VBSs in multiband chemically-doped CsV_(3)Sb_(5)system and offers fresh insights into previously reported Y-shaped ZBCP in a non-quantum-limit condition at the surface of kagome superconductor.

大孔树脂吸附法提取羟基钴胺素

比较了8种大孔树脂对费氏丙酸杆菌发酵提取液光解转化后形成的羟基钴胺素的吸附性能,考察了上柱料液pH值对吸附量的影响,分析了不同浓度和pH下乙醇溶液作为洗脱剂的解吸情况,研究了上柱速率对吸附量和解吸率的影响。结果表明,静态实验中,LX-50B型大孔树脂对羟基钴胺素的吸附性能最好,当上柱溶液pH为6时,LX-50B树脂饱和吸附量最高,为203.87mg/g。用pH为2的60%乙醇溶液作洗脱剂时解吸效果最好,羟基钴胺素提取液以2 BV(床柱体积)/h速度上柱吸附饱和,用60%乙醇溶液以0.5 BV/h速度洗脱后,羟基钴胺素浓度提高至1863.32 mg/L,为原提取液浓度的35倍,纯度由0.38%提升至15.73%,提取纯化效果良好。

Presenilin 2 deficiency facilitates Aβ-induced neuroinflammation and injury by upregulating P2X7 expression

Accumulating evidence suggests that β-amyloid （Aβ）-induced neuroinflammation plays a prominent and early role in Alzheimer＇s disease （AD）. In this study, we demonstrated that Presenilin 2 （PS2） deficiency facilitates Aβ-induced neuroinflammation and injury by upregulating P2X7 expression both in vitro and in vivo. PS2 knockout mice demonstrated increased cognitive impairments and cerebral injury. PS2 deficiency increased the expression of P2X7 both in neurons and microglial cells. Furthermore, extracellular ATP also increased in both Aβ-treated and untreated PS2 knockout microglial cells. Notably, Aβ-induced classical proinflammatory cytokines such as IL-113, IL-1α and TNF-α were increased in PS2 knockout microglial cells, suggesting a potential role for PS2 in the regulation of neuroinflammation. The expression of P2X7 clearly increased in PS2 knockdown BV2 cells. Consistent with in vivo data, Aβ-induced IL-1βproduction was also clearly enhanced in PS2 knockdown BV2 cells. Additionally, expression of the transcription factor Sp was increased in PS2 knockdown cells. When we treated PS2 knockdown ceils with the specific Spl inhibitor MIT, we observed that enhanced P2X7 expression was significantly rescued. Taken together, these data suggests that PS2 plays a protective role during Aβ-induced neuroinflammation and injury through down-regulation of P2X7 expression.

Long-term clinical observation of patients with acute and chronic complete spinal cord injury after transplantation of Neuro Regen scaffold

Spinal cord injury(SCI)often results in an inhibitory environment at the injury site.In our previous studies,transplantation of a scaffold combined with stem cells was proven to induce neural regeneration in animal models of complete SCI.Based on these preclinical studies,collagen scaffolds loaded with the patients’own bone marrow mononuclear cells or human umbilical cord mesenchymal stem cells were transplanted into SCI patients.Fifteen patients with acute complete SCI and 51 patients with chronic complete SCI were enrolled and followed up for 2 to 5 years.No serious adverse events related to functional scaffold transplantation were observed.Among the patients with acute SCI,five patients achieved expansion of their sensory positions and six patients recovered sensation in the bowel or bladder.Additionally,four patients regained voluntary walking ability accompanied by reconnection of neural signal transduction.Among patients with chronic SCI,16 patients achieved expansion of their sensation level and 30 patients experienced enhanced reflexive defecation sensation or increased skin sweating below the injury site.Nearly half of the patients with chronic cervical SCI developed enhanced finger activity.These long-term follow-up results suggest that functional scaffold transplantation may represent a feasible treatment for patients with complete SCI.

Titanium doped kagome superconductor CsV_(3-x)Ti_(x)Sb_(5)and two distinct phases

The vanadium-based kagome superconductor CsV_(3)Sb_(5) has attracted tremendous attention due to its unexcepted anomalous Hall effect(AHE),charge density waves(CDWs),nematicity,and a pseudogap pair density wave(PDW)coexisting with unconventional strong-coupling superconductivity.The origins of CDWs,unconventional superconductivity,and their correlation with different electronic states in this kagome system are of great significance,but so far,are still under debate.Chemical doping in the kagome layer provides one of the most direct ways to reveal the intrinsic physics,but remains unexplored.Here,we report,for the first time,the synthesis of Ti-substituted CsV_(3)Sb_(5) single crystals and its rich phase diagram mapping the evolution of intertwining electronic states.The Ti atoms directly substitute for V in the kagome layers.CsV_(3-x)Ti_(x)Sb_(5) shows two distinct superconductivity phases upon substitution.The Ti slightly-substituted phase displays an unconventional V-shaped superconductivity gap,coexisting with weakening CDW,PDW,AHE,and nematicity.The Ti highly-substituted phase has a U-shaped superconductivity gap concomitant with a short-range rotation symmetry breaking CDW,while long-range CDW,twofold symmetry of in-plane resistivity,AHE,and PDW are absent.Furthermore,we also demonstrate the chemical substitution of V atoms with other elements such as Cr and Nb,showing a different modulation on the superconductivity phases and CDWs.These findings open up a way to synthesise a new family of doped CsV_(3)Sb_(5) materials,and further represent a new platform for tuning the different correlated electronic states and superconducting pairing in kagome superconductors.

Effect of Heat Treatment on the Wear Properties of Selective Laser Melted Ti–6Al–4V Alloy Under Different Loads

As is well known,titanium alloy precipitates when subjected to aging treatment,which poses great influence on its mechanical properties.Thus,solution and solution-aging treatments were conducted in this work,and the wear performance was investigated under diff erent normal loads.The results showed that acicularα′martensite in the original selective laser melted Ti–6 Al–4 V was decomposed intoα+βphases after the solution treatment,and then Ti;Al nanoparticles clusters were further formed in theα-matrix after the solution-aging treatment.The coefficient of friction decreased straightly as the normal load was increased from 20 to 100 N,and the wear mechanisms were characterized by abrasion,adhesive and oxidative wears.The wear rate of solution and solution-aging treated samples increased significantly comparing to the as-built counterpart,but the increment of the solution-aging treated sample was smaller than that of the solution-only treated sample,because of the Ti;Al precipitation in the solution-aging treated sample.These particles provided ball-like effect,reduced material losses and stabilized the wear process.All these factors contributed to the improvement in wear properties of the parts made by selective laser melting.

Chiral flux phase in the Kagome superconductor AV_(3)Sb_(5)

We argue that the topological charge density wave phase in the quasi-2D Kagome superconductor AV3Sb5 is a chiral flux phase.Considering the symmetry of the Kagome lattice,we show that the chiral flux phase has the lowest energy among those states which exhibit 2×2 charge orders observed experimentally.This state breaks the time-reversal symmetry and displays anomalous Hall effect.The explicit pattern of the density of state in real space is calculated.These results are supported by recent experiments and suggest that these materials are new platforms to investigate the interplay between topology,superconductivity and electron–electron correlations.

Establishment of a pseudovirus neutralization assay based on SARS-CoV-2 S protein incorporated into lentiviral particles

The coronavirus disease 2019(COVID‐19)is still causing a wide range of infections and deaths due to the high variability of the severe acute respiratory syndrome coronavirus 2(SARS‐CoV‐2).Therefore,it is necessary to establish a reliable and convenient pseudovirus‐based neutralization assay to develop drug targeted variants of SARS‐CoV‐2.Based on the HIV‐1 backbone,we generated a high titer luciferase(Luc)‐expressing pseudovirus packaging system.Three dominant S mutant substitution pseudovirus were also established and identified compared to wide type in hACE2‐overexpressingHEK‐293T cells(293T‐ACE2 cells).Compared to serine protease inhibitor camostat mesylate,the cysteine protease inhibitor E‐64d could significantly block all SARS‐CoV‐2 mutant S pseudovirus infection in 293T‐ACE2 cells.Furthermore,the neutralization ability of two antibodies targeted receptor‐binding domain(RBD)of SARS‐CoV‐2 spike protein(S)was evaluated,which showeddifferent inhibition dose–effect curves among four types of S pseudovirus.Overall,we developed a pseudovirus‐based neutralization assay for SARS‐CoV‐2,which would be readily adapted to SARS‐CoV‐2 variants for evaluating antibodies.

Colorectal cancer-derived extracellular vesicles induce liver premetastatic immunosuppressive niche formation to promote tumor early liver metastasis

Dear Editor,To date,the effect of colorectal cancer(CRC)-derived extracellular vesicles(EVs)on liver pre-metastatic niche(PMN)remain incompletely understood.1 To investigate the role of CRC-derived EVs in the remodeling of the liver PMN,we isolated EVs from CT26 cell culture supernatant.The characteristics of EVs(the morphology,size,and markers)were identified by transmission electron microscopy(TEM),Nanoparticle Tracking Analysis(NTA),and western blotting(Supplementary Fig.S1a–e).Then,BALB/c mice with an intact liver immune status were pretreated with CRCderived EVs and phosphate-buffered saline(PBS)for one month,and a liver metastasis model was established via spleen injection of tumor cells to determine whether EVs influence liver metastasis(Fig.1a).Two hours after the operation,in vivo imaging indicated that the animal model was successfully established,and the tumor fluorescence intensity in the liver was consistent between the two groups(Supplementary Fig.S2a,b).Amazingly,the liver tumor fluorescence intensity in the EVs group was significantly stronger than that in the PBS group after 24 h(Fig.1b;Supplementary Fig.S2c,d).The number of liver tumor nodules in the EVs group was also significantly higher than that in the PBS group on day 4(Fig.1c;Supplementary Fig.S2e,f).