Design and mechanical properties analysis of a cellular Waterbomb origami structure

Cellular structures are commonly used to design energy-absorbing structures,and origami structures are becominga prevalent method of cellular structure design.This paper proposes a foldable cellular structure based on theWaterbomb origami pattern.The geometrical configuration of this structure is described.Quasi-static compressiontests of the origami tube cell of this cellular structure are conducted,and load-displacement relationship curvesare obtained.Numerical simulations are carried out to analyze the effects of aspect ratio,folding angle,thicknessand number of layers of origami tubes on initial peak force and specific energy absorption(SEA).Calculationformulas for initial peak force and SEA are obtained by the multiple linear regression method.The degree ofinfluence of each parameter on the mechanical properties of the single-layer tube cell is compared.The resultsshow that the cellular structure exhibits negative stiffness and periodic load-bearing capacity,as well as foldingangle has the most significant effect on the load-bearing and energy-absorbing capacity.By adjusting the designparameters,the stiffness,load-bearing capacity and energy absorption capacity of this cellular structure can beadjusted,which shows the programmable mechanical properties of this cellular structure.The foldability andthe smooth periodic load-bearing capacity give the structure potential for application as an energy-absorbing structure.

目标导向的研究性实验与创新能力培养实例——超声波辅助的Fischer酯化反应条件初探

在目标导向的研究性实验与创新能力培养教学活动中,通过方案设计、实施和总结三阶段的教学过程设计,使学生在实验学习过程中体验到科学研究的全过程,培养创新能力。本文以学生未发表的实验报告论文为例,展示教学成果。该报告以苯甲酸乙酯的酯化合成反应为例,比较了超声波辅助条件下不同催化剂对Fischer酯化反应的催化效率,结果表明酸负载的蒙脱土K-10催化效果明显优于浓硫酸催化。同时还比较了负载前后蒙脱土的粉末X射线衍射谱图,并对催化机理进行了初步的讨论。该工作的研究结果表明超声波辅助的Fischer酯化反应条件温和,对小分子酯类化合物合成有一定的借鉴意义。

Precise in-situ and ex-situ study on thermal behavior of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)/graphite coin cell:From part to the whole cell

Multiple mode calorimetry and C80 micro-calorimeter are used to investigate the impact of cathode and anode on heat generation of lithium ion battery.The thermal behaviors of LiNi_(x)Co_(y)Mn_(z)O_(2)/graphite full cell are discussed under normal operating and elevating temperature.Affected by negative entropy change,lithium intercalation presents more exotherms than deintercalation for both electrode materials.The contributions of irreversible and reversible heat to the total heat generation of graphite are evaluated.The phase transitions correlated with voltages and lithium contents are determined.Based on the analysis of half-cell,the effect of two electrodes(with the same capacity)on overall heat generation is nearly the same and anode of full cell plays a key role in charging while cathode dominates in discharging.Thermal behaviors of lithiated graphite and delithiated LiNi_(x)Co_(y)Mn_(z)O_(2) electrolyte and their coexisting system are identified to further explore their influence on battery safety.The breakdown of solid electrolyte interface(SEI)at around 82℃ is considered as a crucial factor affecting the thermal stability of full cell.The oxidation of electrolyte induced by oxygen released from cathode material turns out to be one of the main heat sources.These accurate results are of great significance to improve the existing thermal management system and provide basic data for the prediction of battery performance.

Transition-metal redox evolution and its effect on thermal stability of LiNixCoyMnzO_(2) based on synchrotron soft X-ray absorption spectroscopy

Based on the synchrotron soft X-ray absorption spectroscopy experiments,the fundamental electronic structures of layered Li NixCoyMnzO_(2)(NCM)are investigated systematically and the data of transitionmetal(TM)L-and O K-edges spectra are collected.Distribution of Ni ions under different oxidation states is evaluated according to linear combination fit.It is found that the ratio of Ni^(4+)expands with the increase of Ni since it dominates in charge compensation during charging,and that the existence of Ni^(3+)is nearly negligible in delithiated NCM.The valence state of Co also strongly depends on Ni content,the perceptible position shift of Co L_(3)-edge absorption peak towards higher energy in Ni-rich material agrees well with the small voltage plateau at around 4.2 V.The stability of Mn is verified as no obvious spectral change with the Mn L-edge is observed.Moreover,as Ni content rises,the O 2p holes near the Femi level increases with higher oxidation state of Ni,indicating the enhanced hybridization of O 2p-TM 3 d.Delithiated NCMs with higher Ni content are prior to lose electron existing in highly hybridized Ni3 dO 2 p bands upon heating,which accounts for the pronounced O_(2)release in phase transitions and the deterioration in thermal stability.These detailed observation of the electronic structure evolution is one of the key ingredients to improving the electrochemical and thermal performance of NCM.

Matching characteristics of magnetic field configuration and chamfered channel wall in a magnetically shielded Hall thruster

To date, the selection of the magnetic field line used to match the chamfered inner and outer channel walls in a magnetically shielded Hall thruster has not been quantitatively studied. Hence, an experimental study was conducted on a 1.35 k W magnetically shielded Hall thruster with a xenon propellant. Different magnetic field lines were chosen, and corresponding tangentially matched channel walls were manufactured and utilized. The results demonstrate that high performance and a qualified anti-sputtering effect cannot be achieved simultaneously. When the magnetic field lines that match the chamfered wall have a strength at the channel centerline of less than 12% of the maximum field strength, the channel wall can be adequately protected from ion sputtering. When the magnetic field lines have a strength ratio of 12%–20%, the thruster performance is high. These findings provide the first significant quantitative design reference for the match between the magnetic field line and chamfered channel wall in magnetically shielded Hall thrusters.

Ecological Protection Design Strategy for Mountain Tourism Highway Slopes

Slope ecological protection technology is a form of slope protection with high ornamental and good economic value.At present,it is widely used in highways and urban streets’slope protection works.However,its use is not very common in mountain tourism highways;hence,it is necessary to implement strategies for mountain tourism highway slope ecological protection design to promote excellent development.

The Application Strategy of Tourism Highway Landscape Design

In the context of China's economic development,tourism resources have been continuously developed,and the aesthetic requirements of tourism highway are higher and higher.In order to ensure the good ecological environment and promote the sustainable development of tourism highway in the process of highway construction,it is necessary to analyze the relevant strategies of tourism highway landscape design.

The first chiral cerium halide towards circularly-polarized luminescence in the UV region

Chiral organic-inorganic hybrid metal halides(OIHMHs)have attracted broader scientific community recently in spin lightemitting diodes,and circularly polarized light-emitting diodes.However,the emission peaks of the reported chiral OIHMHs mainly locate in the visible region,and chiral OIHMH with ultraviolet(UV)circularly polarized luminescence(CPL)has been rarely reported.To fill this gap,cerium,a unique rare-earth(RE)element with tunable luminescence from UV to the visible region owing to the 4 f-related electronic transition,was introduced to construct the first RE-based chiral OIHMHs,R/S-MCC.The chirality is successfully transferred from the chiral organic cations to the inorganic cerium chloride framework in R/S-MCC,as confirmed by the single crystal structures,circular dichroism,and CPL.The emission spectra of R/S-MCC are in the UV region,originating from the characteristic d-f transition of Ce^(3+),which making the Ce-based metal halides are ideal candidates towards CPL light sources in the UV region.Notably,R-and S-MCC are the first RE-based OIHMHs,also the first chiral metalhalides with UV CPL.Our work opens a new avenue for the development of the chiral OIHMH family towards RE-based chiral OIHMH.The RE-based chiral metal halides couple the unique and superior optical,electrical,magnetic,and spintronic properties of RE elements with chirality could accelerate the development of chiral optoelectronics and spintronics toward real applications.

超声对晚发型胎儿生长受限不良围产期结局的预测价值

目的探讨超声对晚发型胎儿生长受限(FGR)不良围产期结局的预测因素,并分析其诊断效能。方法回顾性分析2015年12月至2021年5月郑州大学第三附属医院收治的149例产前诊断为晚发型FGR患者的超声声像图及临床资料,按照是否出现不良围产期结局分为不良围产期结局组(72例)和对照组(77例)。记录一般临床资料及分娩前1周内经超声测量的大脑中动脉搏动指数(MCA-PI)、脐动脉搏动指数(UA-PI)、脑胎盘比(CPR)、羊水-脐脑比(AUCR)及估计胎儿体质量(EFW)。采用两独立样本t检验、Mann-WhitneyU检验、χ^(2)检验比较组间上述指标的差异,采用单因素和多因素Logistic逐步回归分析确定晚发型FGR不良围产期结局的预测因素,构建受试者操作特征(ROC)曲线分析各超声参数对不良围产期结局的预测效能。结果与对照组相比,不良围产期结局组AUCR、EFW百分位数、CPR、MCA-PI、最大羊水暗区垂直深度均明显降低[30.63±10.33vs39.70±11.15;3.2(2.1,6.4)vs5.7(3.5,8.9);1.18±0.28vs1.37±0.21;1.22±0.26vs1.34±0.23;27.50(22.00,31.00)mmvs29.00(23.50,34.50)mm],UA-PI明显增高(1.05±0.20vs0.98±0.16),差异具有统计学意义(t=5.138,P<0.001;Z=-4.618,P<0.001;t=4.464,P<0.001;t=3.129,P=0.002;Z=-2.292,P=0.022;t=-2.504,P=0.013)。多因素Logistic逐步回归分析显示AUCR、EFW百分位数、CPR为晚发型FGR不良围产期结局的独立预测因素(OR=0.951、0.753、0.154,P=0.024、<0.001、=0.044)。经过ROC曲线分析,AUCR、EFW百分位数、CPR预测晚发型FGR不良围产期结局的界值、敏感度、特异度分别为39.64、53.2%、81.9%;4.85、66.2%、66.7%;1.19、81.8%、51.4%。AUCR、EFW百分位数、CPR 3个变量联合的多参数模型对不良围产期结局的诊断效能提升,弥补了单项参数预测晚发型FGR不良围产期结局敏感度与特异度失衡的问题,ROC曲线下面积为0.795,敏感度、特异度分别为76.6%、70.8%。结论超声检查在预测晚发型FGR不良围产期结局中具有重要价值,AUCR、EFW百分位数及CPR是晚发型FGR不良围产期结局的独立预测因素,可为产前咨询和临床处理提供依据。

A general powder dusting method for latent fingerprint development based on AIEgens

Powder dusting method is the most practically useful approach for latent fingerprint development in the crime scene. Herein, a general powder dusting method has been explored for latent fingerprint development based on aggregation-induced emission luminogens(AIEgens). A series of tetraphenylethene(TPE) derivatives with multiple diphenylamine(DPA), namely, TPE-DPA,TPE-2 DPA and TPE-4 DPA, were selected as candidates to dope with magnetic powders and applied for latent fingerprint development. After screening, the magnetic powder 3 doped with TPE-4 DPA proves to be the best, in terms of fluorescent intensity, resolution and adhesiveness. Afterwards, the magnetic powder 3 was applied for visualization of latent fingerprint on various smooth and porous substrates, including glass, stainless steel, leaf, ceram, plastic bag, lime wall, wood and paper money.Specific details, such as island, core, termination and bifurcation, can be clearly observed for the fluorescent fingerprint images.

Mathematical Representation of WECC Composite Load Model

Composite load model of Western Electricity Coordinating Council(WECC)is a newly developed load model that has drawn great interest from the industry.To analyze its dynamic characteristics with both mathematical and engineering rigors,a detailed mathematical model is needed.Although composite load model of WECC is available in commercial software as a module and its detailed block diagrams can be found in several public reports,there is no complete mathematical representation of the full model in literature.This paper addresses a challenging problem of deriving detailed mathematical representation of composite load model of WECC from its block diagrams.In particular,we have derived the mathematical representation of the new DERA model.The developed mathematical model is verified using both MATLAB and PSS/E to show its effectiveness in representing composite load model of WECC.The derived mathematical representation serves as an important foundation for parameter identification,order reduction and other dynamic analysis.

Boosting self-trapped exciton emission from Cs_(3)Cu_(2)I_(5)nanocrystals by doping-enhanced exciton-phonon coupling

Self-trapped excitons(STEs)emission from halide perovskites with strong exciton-phonon coupling has attracted considerable attention due to the widespread application in optoelectronic devices.Nevertheless,the in-depth understanding of the relationship between exciton-phonon coupling and luminescence intensity remains incomplete.Herein,a doping-enhanced exciton-phonon coupling effect is observed in Cs_(3)Cu_(2)I_(5)nanocrystals(NCs),which leads to a remarkable increasement of their STEs emission efficiency.Mechanism study shows that the hetero-valent substitution of Cu+with alkaline-earth metal ions(AE^(2+))causes a greater degree of Jahn-Teller distortion between the ground state and excited state structures of[Cu_(2)I_(5)]_(3)-clusters as evidenced by our spectral analysis and first-principles calculations.As a consequence,an X-ray detector based on these Cs_(3)Cu_(2)I_(5):AE NCs delivers an X-ray imaging resolution of up to 10 lp·mm^(-1) and a low detection limit of 0.37μGyair·s^(-1),disclosing the potential of doping-enhanced exciton-phonon coupling effect in improving STEs-emission and practical application for X-ray imaging.

Information Entropy Based Prioritization Strategy for Data-driven Transient Stability Batch Assessment

Transient stability batch assessment(TSBA)is es-sential for dynamic security check in both power system planning and day-ahead dispatch.It is also a necessary technique to generate sufficient training data for data-driven online transient stability assessment(TSA).However,most existing work suffers from various problems including high computational burden,low model adaptability,and low performance robustness.Therefore,it is still a significant challenge in modern power systems,with numerous scenarios(e.g.,operating conditions and"N-k"contin-gencies)to be assessed at the same time.The purpose of this work is to construct a data-driven method to early terminate time-domain simulation(TDS)and dynamically schedule TSBA task queue a prior,in order to reduce computational burden without compromising accuracy.To achieve this goal,a time-adaptive cas-caded convolutional neural networks(CNNs)model is developed to predict stability and early terminate TDS.Additionally,an information entropy based prioritization strategy is designed to distinguish informative samples,dynamically schedule TSBA task queue and timely update model,thus further reducing simulation time.Case study in IEEE 39-bus system validates the effectiveness of the proposed method.

Synthesis and immunological evaluation of Mincle ligands-based antitumor vaccines

The development of novel adjuvants constitutes a new strategy for the research of tumor vaccines.Immunomodulatory molecule adjuvants are one of the novel adjuvants that can effectively stimulate the pattern recognition receptors to activate the downstream pathways of immune cells.However,there are few studies on immunomodulatory molecular adjuvants associated with C-type lectin.It has been reported that GlcC_(14)C_(18)is a Mincle ligand with a relatively simple structure and strong adjuvant activity in vivo.Herein,we coupled GlcC_(14)C_(18)with MUC1 glycopeptide and evaluated its immune effect.In addition,we also synthesized α-GlcC_(14)C_(18)-MUC1 and β-GlcC_(14)C_(18)-MUC1 based on the two configurations of GlcC_14C_(18)and compared their immune effects.The results show that both of the two configurations of the vaccine have a good immune effect,but to a certain extent,the immune effect of β-GlcC_(14)C_(18)-MUC1 is better than that of α-GlcC_(14)C_(18)-MUC1.

DESI Legacy Imaging Surveys Data Release 9:Cosmological constraints from galaxy clustering and weak lensing using the minimal bias model

We present a tentative constraint on cosmological parameters Ω_(m) and σ_(8) from a joint analysis of galaxy clustering and galaxygalaxy lensing from DESI Legacy Imaging Surveys Data Release 9(DR9),covering approximately 10000 square degrees and spanning the redshift range of 0.1 to 0.9.To study the dependence of cosmological parameters on lens redshift,we divide lens galaxies into seven approximately volume-limited samples,each with an equal width in photometric redshift.To retrieve the intrinsic projected correlation function w_(p)(r_(p))from the lens samples,we employ a novel method to account for redshift uncertainties.Additionally,we measured the galaxy-galaxy lensing signal ΔΣ(r_(p))for each lens sample,using source galaxies selected from the shear catalog by applying our Fourier Quad pipeline to DR9 images.We model these observables within the flatΛCDM framework,employing the minimal bias model.To ensure the reliability of the minimal bias model,we apply conservative scale cuts:r_(p)>8 and 12 h^(-1)Mpc,for w_(p)(r_(p))and ΔΣ(r_(p)),respectively.Our findings suggest a mild tendency that S_(8)=σ_(8)√Ω_(m)/0.3increases with lens redshift,although this trend is only marginally significant.When we combine low redshift samples,the value of S8is determined to be 0.84±0.02,consistent with the Planck results but significantly higher than the 3×2 pt analysis by 2-5σ.Despite the fact that further refinements in measurements and modeling could improve the accuracy of our results,the consistency with standard values demonstrates the potential of our method for more precise and accurate cosmology in the future.

The clustering of galaxies in the DESI imaging legacy surveys DR8:I. The luminosity and color dependent intrinsic clustering

In a recent study,we developed a method that models the impact of photometric redshift uncertainty on the two-point correlation function (2PCF).Using this method,we simultaneously obtained both the intrinsic clustering strength and the photometric redshift errors by fitting the projected 2PCF with two integration depths along the line-of-sight.Herein,we apply this method to the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys Data Release 8 (LS DR8),which is the largest galaxy sample currently available.We separate the galaxies into 20 samples in eight redshift bins,from z=0.1 to z=1.0,and several z-band absolute magnitude bins,with M_(z)≤-20.These galaxies are further divided into red and blue subsamples according to their M_(r)^(0.5)-M_(z)^(0.5) colors.We measure the projected 2PCFs for all these galaxy subsamples and fit them using our photometric redshift 2PCF model.We find that the photometric redshift errors are smaller in the red subsamples than in the overall population.In contrast,some systematic photometric redshift errors exist in the blue subsamples,such that some of the subsamples show a significantly enhanced 2PCF on large scales.Therefore,separately focusing only on the red subsamples and on all the subsamples,we find that the biases of the galaxies in these subsamples exhibit clear color,redshift,and luminosity dependencies;the brighter red galaxies at higher redshift are more biased than their bluer and low-redshift counterparts.Apart from the best-fit set of parameters,σz and b,from this state-of-the-art photometric redshift survey,we obtain high-precision intrinsic clustering measurements for these 40 red-and all-galaxy subsamples.These measurements,on large and small scales,hold important information regarding cosmology and galaxy formation that will be used in our subsequent probes in this series.

Enhancing the immune response and tumor suppression effect of antitumor vaccines adjuvanted with non-nucleotide small molecule STING agonist

Vaccine adjuvants have been widely used to enhance the immunogenicity of the antigens and elicit long-lasting immune response.However,only few vaccine adjuvants have been approved by the FDA for human use so far.Therefore,there is still an urgent need to develop novel adjuvants for the potential applications in clinical trials.Herein,non-nucleotide small molecule STING agonist di ABZI was employed to construct glycopeptide antigen based vaccines for the first time.Immunological evaluation indicated di ABZI not only enhanced the production of antibodies and T cell immune responses,but also inhibited tumor growth in tumor-bearing mice in glycopeptide-based subunit vaccines.These results indicated that di-ABZI demonstrates a high potential as adjuvant for the development of cancer vaccines.