Temperature effect on nanotwinned Ni under nanoindentation using molecular dynamic simulation

Temperature effect on atomic deformation of nanotwinned Ni (nt-Ni) under localized nanoindentation is investigated in comparison with nanocrystalline Ni (nc-Ni) through molecular simulation.The nt-Ni exhibits enhanced critical load and hardness compared to nc-Ni,where perfect,stair-rod and Shockley dislocations are activated at (111),(111) and (111) slip planes in nt-Ni compared to only SSockley dislocation nucleation at (111) and (111) slip planes of nc-Ni.The nt-Ni exhibits a less significant indentation size effect in comparison with nc-Ni due to the dislocation slips hindrance of the twin boundary.The atomic deformation associated with the indentation size effect is investigated during dislocation transmission.Different from the decreasing partial slips parallel to the indenter surface in nc-Ni with increasing temperature,the temperaturedependent atomic deformation of nt-Ni is closely related to the twin boundary:from the partial slips parallel to the twin boundary (~10 K),to increased confined layer slips and decreased twin migration(300 K–600 K),to decreased confined layer slips and increased dislocation interaction of dislocation pinning and dissociation (900 K–1200 K).Dislocation density and atomic structure types through quantitative analysis are implemented to further reveal the above-mentioned dislocation motion and atomic structure alteration.Our study is helpful for understanding the temperature-dependent plasticity of twin boundary in nanotwinned materials.

分析延续性护理对糖尿病肾病患者服药依从性及负性情绪的影响

目的分析糖尿病肾病患者实施延续性护理的影响。方法选取2021年9月—2023年6月巨野县人民医院收治的66例糖尿病肾病患者为研究对象,按护理方法不同分为对照组、观察组,各33例。对照组行常态性护理,观察组行延续性护理。比较两组服药依从性、负性情绪(焦虑自评量表、抑郁自评量表)、自护能力、血糖指标(空腹血糖、餐后2 h血糖)。结果观察组服药依从率(93.94%)高于对照组(72.73%),差异有统计学意义(χ^(2)=5.346,P<0.05)。施护后,观察组焦虑自评量表、抑郁自评量表评分均低于对照组,观察组自护优良率高于对照组,观察组各血糖指标均低于对照组,差异有统计学意义(P均<0.05)。结论延续性护理方案对服药依从性可产生正面影响,能减轻糖尿病肾病患者的情绪问题,提升自护能力,改善其在院外的生活状态。

民办院校英语教师科研能力现状与对策研究

民办院校教师科研能力是一个值得探讨的研究课题。文章以贵州某民办高校的英语教师为调研对象,主要采用了对比分析法、深度访谈法、文献资料法等,具体分析了该校英语教师在“转设”前后科研能力的发展现状。我们建议从内外两个层面优化该校英语教师的科研能力:外部层面,增加科研经费投入,落实对科研管理人员的考评和提倡唯物主义优良传统作风;内部层面,引入人性化管理模式,吸引外部可利用的资源和促进英语教师自身科研素质的提高。这对民办院校如何重视科研、如何实现学校的可持续发展具有重大的现实意义。

Stress drop assessment of the August 8, 2017, Jiuzhaigou earthquake sequence and its tectonic implications

By using a broadband Lg attenuation model developed for the Tibetan Plateau,we isolate source terms by removing attenuation and site effects from the observed Lg-wave displacement spectra of the M 7.0 earthquake that occurred on August 8,2017,in Jiuzhaigou,China,and its aftershock sequence.Thus,the source parameters,including the scalar seismic moment,comer frequency and stress drop,of these events can be further estimated.The estimated stress drops vary from 47.1 kPa to 7149.6 kPa,with a median value of 59.4 kPa and most values falling between 50 kPa and 75 kPa.The estimated stress drops show significant spatial variations.Lower stress drops were mainly found close to the mainshock and on the seismogenic fault plane with large coseismic slip.In contrast,the highest stress drop was 7.1 MPa for the mainshock,and relatively large stress drops were also found for aftershocks away from the major seismogenic fault and at depths deeper than the zone with large coseismic slip.By using a statistical method,we found self-similarity among some of the aftershocks with a nearly constant stress drop.In contrast,the stress drop increased with the seismic moment for other aftershocks.The amount of stress released during earthquakes is a fundamental characteristic of the earthquake rupture process.As such,the stress drop represents a key parameter for improving our understanding of earthquake source physics.

Surgery-first for a patient with mild hemifacial microsomia: A case report and review of literature

BACKGROUND Hemifacial microsomia(HFM)is the second most common craniofacial congenital anomaly following cleft lip and palate.Because of the various phenotypic spectra and the severity of the deformity,a wide range of treatment approaches have been proposed.Recently,the surgery-first approach(SFA)was introduced to treat mild to moderate HFM,and it yielded a balanced facial appearance.The SFA not only promotes rapid improvement in facial aesthetics but also considerably reduces the overall treatment time.CASE SUMMARY A female patient,aged 25 years old,sought orthodontic treatment with the chief complaint of dental and facial asymmetry.After a comprehensive physical examination and imaging analysis were performed,the patient was diagnosed with mild HFM that was primarily attributed to unilateral abnormal development of the maxilla-mandibular.The SFA was carried out to correct the skeletal deformity.The palatal suture was used as the midline of the maxilla in the surgical plan to center the maxilla,and the chin was also properly positioned to obtain a relatively symmetrical facial appearance.Four weeks after the surgery,the patient was referred for postsurgical orthodontics to decompensate the dentition and stabilize the occlusion.After 20 mo of treatment,all orthodontic appliances were removed.The posttreatment photographs of the patient and her smile confirmed good aesthetic and occlusal results.CONCLUSION Mild HFM can be corrected by SFA,which not only promotes rapid improvement in facial aesthetics but also considerably reduces the overall treatment time.

Electrochemical behaviors of silicon wafers in silica slurry

The electrochemical behaviors of n-type silicon wafers pH value and solid content of the slurry on the corrosion of silicon in silica-based slurry were investigated, and the influences of the wafers were studied by using electrochemical DC polarization and AC impedance techniques. The results revealed that these factors affected the corrosion behaviors of silicon wafers to different degrees and had their suitable parameters that made the maximum corrosion rate of the wafers. The corrosion potential of （100） sttrface was lower than that of（111）, whereas the current density of （100） was much higher than that of（111）.

The testis-specifically expressed gene Trim69 is not essential for fertility in mice

Protein ubiquitination is essential for diverse cellular functions including spermatogenesis.The tripartite motif(TRIM)family proteins,most of which have E3 ubiquitin ligase activity,are highly conserved in mammals.They are involved in important cellular processes such as embryonic development,immunity,and fertility.Our previous studies indicated that Trim69,a testis-specific expressed TRIM family gene,potentially participates in the spermatogenesis by mediating testicular cells apoptosis.In this study,we investigated the biological functions of Trim69 in male mice by established Trim69 knockout mice with CRISPR/Cas9 genomic editing technology.Here,we reported that the male Trim69 knockout mice had normal fertility.The adult knockout mice have shown that the appearance of testes,testis/body weight ratios,testicular histomorphology,and the number and quality of sperm were consistent with wild-type mice.These results indicated that the E3 ubiquitin ligase protein Trim69 was not essential for male mouse fertility,and it might be compensated by other TRIM family members such as Trim58 in Trim69-deficiency testis.This study would help to elucidate the functions of tripartite motif protein family and the regulation of spermatogenesis.

Pleomorphic adenoma of the trachea:A case report and review of the literature

BACKGROUND Pleomorphic adenoma(PA)is the most common benign tumor that occurs in the salivary glands;however,tracheobronchial PA is rarely observed.To the best of our knowledge,fewer than 50 cases have been reported in the literature.We report a 49-year-old woman who had been treated for asthma for 2 years before being diagnosed with PA of the trachea.CASE SUMMARY A 49-year-old woman was referred to our hospital due to dyspnea upon exertion and chronic cough with wheezing for 2 years.Laboratory tests showed an elevated white blood cell count,absolute neutrophil count,and percentage of neutrophils.A chest computerized tomography scan showed a well-defined,softtissue density lesion measuring 2.4 cm×2.1 cm in the lower trachea.Flexible bronchoscopy revealed that nearly 90%of the tracheal lumen was obstructed.The histopathological and immunohistochemistry features suggested PA of the trachea.Furthermore,we review the characteristics of 29 patients with tracheobronchial PA over the last 30 years.CONCLUSION Tracheobronchial PA occurs without gender predominance,mostly in the lower or upper trachea,and has a low recurrence rate.The median age at diagnosis is 48 years.The most common symptoms are cough,stridor,dyspnea,and wheezing.

Influence of Reading Behavior of Entrepreneurs on Their Entrepreneurial Performance: Empirical Study of Chongqing

In the context of economic downward and industrial structural adjustment,cultural level of entrepreneurs exerts direct influence on entrepreneurial results,while reading behavior of entrepreneurs is closed connected with cultural level of entrepreneurs. Therefore,it is of utmost importance to analyze the relation between reading behavior and entrepreneurial performance. Based on the survey data of 200 enterprises in one- hour economic circle of Chongqing,this paper analyzed three dimensions of reading behavior of entrepreneurs: reading subjects,reading media,and reading environment. It analyzed the relation between these three indicators and entrepreneurial performance. It further divided entrepreneurial performance into survival performance and financial performance. Finally,it came up with following conclusions:( i) good reading exerts significantly positive effect on survival performance of entrepreneurial enterprises;( ii) suitable reading environment plays a positive role in financial performance of entrepreneurial enterprises.

Recent Advances in Electrolytes for High-Voltage Cathodes of Lithium-Ion Batteries

With the increasing scale of energy storage,it is urgently demanding for further advancements on battery technologies in terms of energy density,cost,cycle life and safety.The development of lithium-ion batteries(LIBs)not only relies on electrodes,but also the functional electrolyte systems to achieve controllable formation of solid electrolyte interphase and high ionic conductivity.In order to satisfy the needs of higher energy density,high-voltage(>4.3 V)cathodes such as Li-rich layered compounds,olivine LiNiPO_(4),spinel LiNi_(0.5)Mn_(1.5)O_(4) have been extensively studied.However,high-voltage cathodebased LIBs fade rapidly mainly owing to the anodic decomposition of electrolytes,gradually thickening of interfacial passivation layer and vast irreversible capacity loss,hence encountering huge obstacle toward practical applications.To tackle this roadblock,substantial progress has been made toward oxidation-resistant electrolytes to block its side reaction with high-voltage cathodes.In this review,we discuss degradation mechanisms of electrolytes at electrolyte/cathode interface and ideal requirements of electrolytes for high-voltage cathode,as well as summarize recent advances of oxidation-resistant electrolyte optimization mainly from solvents and additives.With these insights,it is anticipated that development of liquid electrolyte tolerable to high-voltage cathode will boost the large-scale practical applications of high-voltage cathode-based LIBs.

Discrete element modeling and verification of the simulation parameters for chopped hybrid Broussonetia papyrifera stems

In this study,the discrete element software EDEM was applied to establish a simulation model of non-uniform-sized particle units for Broussonetia papyrifera stalks,which aimed to address the low utilization rate of existing Broussonetia papyrifera harvesting machinery,the significant variation between the simulated model of Broussonetia papyrifera stalks and their actual appearance,as well as the absence of contact parameter calibration.Through a combination of the free-fall collision method,inclined plane sliding method,and inclined plane rolling method,numerical simulation was conducted to analyze the pattern of variations in contact parameters between Broussonetia papyrifera stalks and the steel material of the machinery.Accordingly,these parameters were calibrated.The results showed that the coefficient of restitution between Broussonetia papyrifera stalks and steel materials was 0.321,the static friction factor was 0.589,and the rolling friction factor was 0.078.With the parameters of contact between Broussonetia papyrifera stalks as variables and the experimentally measured pile angle as the objective of optimization,the steepest ascent experiment and the three-factor five-level rotation combination experiment were conducted.In this way,a second-order response model was constructed to analyze the relationship between the contact parameters and the pile angle.Through the optimization analysis of experimental data,it was determined that the coefficient of restitution between Broussonetia papyrifera stalks was 0.21,the static friction factor was 0.24,and the rolling friction factor was 0.03.Furthermore,the calibration results were validated through experimentation to show that the relative error between the obtained pile angle under the context of optimal parameter combination and the actual one was 4.11%.In addition,the relative error of mass flow rate in spiral transport was within a reasonable range,this study lays a foundation both theoretically and statistically for the simulation of contact parameters for Broussonetia papyrifera stalk harvesting processing,mechanical harvesting,and so on.

PEG400-mediated nanocarriers improve the delivery and therapeutic efficiency of mRNA tumor vaccines

Dendritic cell(DC)-targeted delivery of mRNA is a prominent method to boost the efficacy of mRNA tumor vaccines.The targeting ligands are often modified on nanocarriers by polyethylene glycol(PEG)linker in mRNA delivery systems.Whether the PEG linker length influences the targeting delivery efficiency of mRNA nanocarrier in vivo remains unclear.Here,we designed and constructed DC-targeted mRNA delivery systems modified by mannose via different PEG linker lengths(100/400/1000/2000)(MPn-LPX).The top candidate MP_(400)-LPX(the linker was PEG400)showed the optimal mRNA expression and antigen presentation owing to the highly efficient uptake by DCs.Furthermore,MP_(400)-LPX could better inhibited tumor growth and extended survival in the E.G7-OVA lymphoma and TC-1 cervical tumor mouse model.Collectively,these results demonstrated that PEG400 was the optimal linker for the PEGylated DC-targeted mRNA vaccines.Our findings provided a new platform for the rational design of targeted mRNA nanovaccines with shorter-length PEG.

温度-应力耦合条件下聚四氟乙烯的压缩蠕变行为与寿命预测

利用自行设计搭建的人工加速老化实验装置,研究了聚四氟乙烯(PTFE)在温度-应力耦合作用下的压缩蠕变行为。结果表明,随温度或应力上升,平衡压缩应变呈增加趋势,该过程以物理老化为主,并伴随晶区分子链螺旋程度降低和片层滑移。以典型实验条件下聚四氟乙烯的非线性蠕变数据为依据,通过构建合适的位移因子,建立了符合广义蠕变柔度曲线的寿命预测模型。进一步选择应变量作为失效判据,合理预测了不同温度条件下材料的压缩蠕变寿命。通过与实验结果比对,证实该模型对聚四氟乙烯寿命预测准确可靠,且对于有类似蠕变行为的高分子材料寿命预测具有一定的普适性和指导性。

基于谐响应分析的水环境下核主泵叶轮动应力研究

准确计算核主泵叶轮在流体介质中的动应力对核主泵安全可靠运行具有十分重要的意义。本文开展了基于谐响应分析的叶轮动应力的研究,完成了叶轮模态分析、阻尼比分析,压力脉动分析以及动应力分析。得到了叶轮各阶模态频率、叶轮阻尼比以及压力荷载,并对比了缩尺模型实验与数值模拟水力性能,计算了叶轮动应力。结果表明,叶轮湿模态频率比干模态频率低;叶轮流体介质阻尼比比材料阻尼比大一个数量级,并且基本不随着振幅变化;缩尺模型试验与数值模拟水力性能最大误差为2.8%;叶片表面压力脉动主要表现为转频及其谐频振动;叶轮共振模态为1节径1模态,最大动应力为2.02MPa。本文通过分析叶轮模态、阻尼比、压力荷载以及动应力,提供了水环境下叶轮动应力分析方法。

含间位取代吡啶端基的新型pH荧光探针的合成与性能

设计并合成了一种适用于酸性条件的新型pH荧光探针2,8-双((E)-2-(吡啶-3-基)乙烯基)-6H,12H-5,11-甲二苯并[b,f][1,5]重氮(TBMP)。探针TBMP以朝格尔碱为骨架,两翼引入间位取代的吡啶端基,其结构经1H NMR、13C NMR和HR-MS(ESI)表征。并利用pH滴定实验和DFT理论计算探索了探针的pH值变化响应机理。结果表明:探针TBMP由于其间位取代的取代位置效应,显示出独特的两步质子化过程以及特殊的紫外和荧光响应。此外,该探针可以有效地探测酸性pH值(6.5~3.11),并具有良好的稳定性、选择性和较大的斯托克斯位移(127 nm)。

Numerical simulation of Gurney flap on SFYT15thick airfoil

A two-dimensional steady Reynolds-averaged Navier-Stokes （RANS） equation was solved to investigate the effects of a Gurney flap on SFYT15 thick airfoil aerodynamic performance. This airfoil was designed for flight vehicle operating at 20 km altitude with freestream velocity of 25 m/s, The chord length （C） is 5 m and the Reynolds number based on chord length is Re = 7.76 × 10^5. Gurney flaps with the heights ranging from 0.25%C to 3%C were investigated. The shear stress transport （SST） k-ω turbulence model was used to simulate the flow structure around the airfoil. It is showed that Gurney flap can enhance not only the prestall lift but also lift-to-drag ratio in a certain range of angles of attack. Specially, at cruise angle of attack （ω = 3°）, Gurney flap with 0.5%C height can increase lift-to-drag ratio by 2.7%, and lift coefficient by 12.9%, respectively. Furthermore, the surface pressure distribution, streamlines and trailing-edge flow structure around the airfoil are illustrated, which are helpful to understand the mechanisms of Gurney flap on airfoil aerodynamic performance. Moreover, it is found that the increase of airfoil drag with Gurney flap can be attributed to the increase of pressure drag between the windward and the leeward sides of Gurney flat itself.

Promoting the protonation step on the interface of titanium dioxide for selective photocatalytic reduction of CO_(2)to CH_(4)by using red phosphorus quantum dots

Enhancing the selectivity of hydrocarbon in CO_(2)is a great challenge.Herein,taking widely-used and highly-stable TiO_(2)as an example,we found that the protonation step,the key step for CH_(4)production,can change from endoergic to exoergic by using red phosphorus quantum dots.Consequently,the main product in CO_(2)reduction can be shifted from CO into CH_(4).The preparation method is very simple,which just ultrasonically treating the red P in the presence of TiO_(2).With an initial rate of CH_(4)production of 4.69μmol·g^(-1)·h^(-1),under simulated solar light,it manifests a significant 49.4-fold enhancement of CH_(4)yield over TiO_(2).Density functional calculation indicates that the red P optimizes the surface electronic structure.The Gibbs free energy for CHO^(*)formation(^(-1).12 eV)becomes lower than the desorption energy of the CO(-0.01 eV)when red P is introduced.This indicates that the CO intermediates on the surface are rapidly protonated to produce CHO^(*).Subsequently,the CHO^(*)will be converted into CH_(4)instead of being desorbed from the surface to produce CO.This study demonstrates that red P quantum dot is a promising candidate for the development of efficient photocatalyst for CO_(2)photoreduction to CH_(4)under solar light irradiation.

Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process

BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate （Ba（CH3COO2） and tetrabutyl titanate （Ti（OC4H9）4） as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry （TG/DSC）, X-ray diffraction （XRD） and transmission electron microscope （TEM）. The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.

Isolation and Screening of Oenococcus oeni and Its Medium Optimization

[Objectives] This study was conducted to further improve the application of Oenococcus oeni in the wine brewing industry. [Methods] O. oeni was isolated, screened, and identified, and medium optimization was performed to determine the best medium, temperature and oxygen conditions. [Results] O. oeni grew better in mFT80 medium, and the culture conditions were 25 ℃ and an anaerobic condition. [Conclusions] This study provides a reference for the development of China’s wine industry.

A novel heterologous receptor-binding domain dodecamer universal mRNA vaccine against SARS-CoV-2 variants

There are currently approximately 4000 mutations in the SARS-CoV-2 S protein gene and emerging SARS-CoV-2 variants continue to spread rapidly worldwide.Universal vaccines with high efficacy and safety urgently need to be developed to prevent SARS-CoV-2 variants pandemic.Here,we described a novel self-assembling universal mRNA vaccine containing a heterologous receptorbinding domain(HRBD)-based dodecamer(HRBD^(dodecamer))against SARS-CoV-2 variants,including Alpha(B.1.1.7),Beta(B.1.351),Gamma(B.1.1.28.1),Delta(B.1.617.2)and Omicron(B.1.1.529).HRBD containing four heterologous RBD(Delta,Beta,Gamma,and Wild-type)can form a stable dodecameric conformation under T4 trimerization tag(Flodon,FD).The HRBD^(dodecamer)-encoding mRNA was then encapsulated into the newly-constructed LNPs consisting of a novel ionizable lipid(4N4T).The obtained universal mRNA vaccine(4N4T-HRBD^(dodecamer))presented higher efficiency in mRNA transfection and expression than the approved ALC-0315 LNPs,initiating potent immune protection against the immune escape of SARS-CoV-2 caused by evolutionary mutation.These findings demonstrated the first evidence that structure-based antigen design and mRNA delivery carrier optimization may facilitate the development of effective universal mRNA vaccines to tackle SARS-CoV-2 variants pandemic.