Phonon transport properties of Janus Pb_(2)XAs(X=P,Sb,and Bi)monolayers:A DFT study

Grasping the underlying mechanisms behind the low lattice thermal conductivity of materials is essential for the efficient design and development of high-performance thermoelectric materials and thermal barrier coating materials.In this paper,we present a first-principles calculations of the phonon transport properties of Janus Pb_(2)PAs and Pb_(2)SbAs monolayers.Both materials possess low lattice thermal conductivity,at least two orders of magnitude lower than graphene and h-BN.The room temperature thermal conductivity of Pb_(2)SbAs(0.91 W/m K)is only a quarter of that of Pb_(2)PAs(3.88 W/m K).We analyze in depth the bonding,lattice dynamics,and phonon mode level information of these materials.Ultimately,it is determined that the synergistic effect of low group velocity due to weak bonding and strong phonon anharmonicity is the fundamental cause of the intrinsic low thermal conductivity in these Janus structures.Relative regular residual analysis further indicates that the four-phonon processes are limited in Pb_(2)PAs and Pb_(2)SbAs,and the three-phonon scattering is sufficient to describe their anharmonicity.In this study,the thermal transport properties of Janus Pb_(2)PAs and Pb_(2)SbAs monolayers are illuminated based on fundamental physical mechanisms,and the low lattice thermal conductivity endows them with the potential applications in the field of thermal barriers and thermoelectrics.

Crustal and uppermost mantle structure of the northeastern Qinghai-Xizang Plateau from joint inversion of surface wave dispersions and receiver functions with P velocity constraints

Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.

Milestone progress of the HEPS booster commissioning

The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring.The full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target values.These milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam commissioning.As measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,respectively.This paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.

割集功率空间上静态电压稳定域的实用边界

提出了电力系统在割集功率空间上静态电压稳定域边界的实用表达方法。用临界割集将系统分为地理上互不连通的两部分,即相对集中的弱节点区域和非弱节点区域,利用连续潮流,搜索大量的电压稳定临界点,以临界割集上线路的有功和无功潮流为坐标,并通过最小二乘法,将获得的临界点以超平面的形式拟合出电压稳定域的边界,其误差可满足工程应用的要求。这种方法既达到了使复杂电力系统降维的目的,又方便了运行人员监视系统稳定性。同时,电压稳定域边界以超平面形式表示,为电力系统的在线安全分析、评估和优化提供了简明、方便的解析工具。该方法在IEEE 14节点、IEEE 39节点、IEEE 118节点等系统和EPRI 1000节点系统的算例中得到了很好的验证,均以较小误差满足工程需要。

基于有功功率小扰动分析的动态安全域求解

动态安全域(DSR)的暂态稳定边界可以近似表示为超平面,由此提出了一种DSR的快速求解方法。该方法分别对事故前系统的稳定运行点、事故中系统的故障轨迹和事故后系统的暂态稳定性进行有功功率的小扰动分析,然后依据整个暂态响应过程中状态变量的连续性,将不同阶段的分析结果联系起来,最终推导出了超平面形式的DSR解析表达式。应用暂态能量函数分析给出了注入空间上的实用动态安全判据,以此来量化暂态稳定性指标,从而实现对事故后系统的有功功率小扰动分析。该方法的有效性在New England 10机39节点系统上得到了验证。

Primary Malignant Melanoma of the Larynx:Case Report and Literature Review

Primary malignant melanoma of the larynx is extremely rare.This paper reports a case of a patient with primary malignant melanoma of the larynx.Preoperative laryngoscopy revealed a cauliflower-like mass in the supraglottic region,and a CT scan of the pharynx suggested laryngeal cancer with cervical lymph node metastasis.The patient underwent a total laryngectomy with lymph node dissection,and postoperative pathology confirmed a malignant melanoma in the supraglottic region of the larynx.

液滴在超疏水植物叶面的沉积:实验和分子动力学模拟

农药液滴在靶标植物叶面的动态沉积对于提高农药利用率具有重要的意义,特别是在超疏水植物叶面的动态沉积。在本文中,我们利用生物基表面活性剂和甘油之间的氢键作用来增强液滴在超疏水植物叶面的有效沉积。在较低浓度的山梨醇-烷基胺表面活性剂溶液中,添加0.001%的甘油,可有效抑制液滴在不同超疏水/疏水植物叶片表面的弹跳和飞溅行为。结果表明,甘油的加入并没有显著改变山梨醇-烷基胺表面活性剂溶液的表面张力、粘度和聚集体的形态。核磁共振波谱(DOSY)显示,甘油加速了山梨醇-烷基胺表面活性剂分子的扩散速度。利用分子动力学模拟,对山梨醇-烷基胺表面活性剂/甘油体系的能量演化及表面活性剂相对于固体表面距离的分布进行了研究。这项目工作不仅为抑制液滴在植物叶面的弹跳飞溅提供了一种建设性的方法,而且为选择农用表面活性剂提供了理论基础。

生物聚氨酯/羟基磷灰石微相分离与形状记忆性能

形状记忆功能化生物聚氨酯在医用植入体材料中备受关注,而聚氨酯的形状记忆性能与其微相分离结构密切相关。文中以可降解聚己内酯二醇(PCL-diol)、脂环形异佛尔酮二异氰酸酯(IPDI)、1,4-丁二醇(BDO)为单体通过两步法合成生物聚氨酯(PU),以溶液共混的方式加入PU基体中,制备了一系列聚氨酯/羟基磷灰石(PU/HA)复合材料。通过场发射扫描电子显微镜、傅里叶变换红外光谱、热失重分析和动态力学热分析等不同表征方法研究了HA的引入对PU基体微相分离的影响,及其与宏观形状记忆性能的关系,并考察了材料的生物安全性。结果表明,HA的引入明显促进了PU的微相分离,随着HA含量的增加,硬段与软段的玻璃化转变温度差值越大,表明微相分离程度越高。在HA质量分数低于15%时,HA的含量越高,形状回复越快,表明微相分离程度越高,形状记忆性能越好。L929细胞毒性测试结果显示,PU/HA具有良好的细胞安全性,在医用骨修复领域有潜在的应用价值。

基于UPLC-Q-TOF-MS/MS快速鉴定腰康宁汤中化学成分

目的采用超高效液相色谱串联四级杆飞行时间质谱联用(UPLC-Q-TOF-MS/MS)技术对腰康宁汤中化学成分进行快速鉴定。方法采用ACQUITY UPLC BEH C_(18)色谱柱(150 mm×2.1 mm,1.7μm),流动相为0.2%甲酸水溶液-甲醇,梯度洗脱,流速:0.5 mL·min^(-1),柱温:40℃,进样量:3μL;电子喷雾离子源,在正、负离子模式下对色谱流出物质进行质谱检测。结果通过与对照品对照和结合文献,从腰康宁汤中鉴定出山奈苷、宝藿苷Ⅰ、葛根素、毛蕊异黄酮苷、芍药苷、夏佛塔苷、芒柄花苷、丹酚酸B、二十八烷酸、2-乙氧羰基-5,7-二羟基-4-甲氧基异黄酮10种成分。结论建立的定性分析方法能快速、系统地分析腰康宁汤中的化学成分,为该方的质量控制及药效物质基础研究提供了理论基础。

动态能力视角下制造企业数字化转型路径——基于步科公司的案例研究

加快制造业数字化转型是当前我国的重大发展战略,本文采用扎根理论编码方法对一家制造企业展开纵向案例研究,试图打开制造企业数字化转型过程的数字能力"黑箱"。研究发现:(1)制造企业的数字化转型需要构建的动态能力包括数字感知能力、数字获取能力和数字转化能力,并进一步细化为七个子能力;(2)数字获取能力是数字化转型过程中的关键能力,只有实现数据可采集,连通不同业务场景的数字化,实现数据的协同,数据才具有穿透力,从而发现生产过程中的"瓶颈";(3)制造端触发的数字化转型影响,显性且短期可实现的是供应链效率的提升,其中改善生产过程的触发机制发生显著变化,由此引发管理模式革新和商业模式创新。研究揭示了数字工厂建设过程中动态能力变化与重构的内在机理,拓展和丰富了数字时代企业动态能力的理论情境和内涵。

失稳模态识别方法及其在动态安全域中的运用

提出了一种快速识别初始运行点附近失稳模态的方法,该方法基于大量计算观察到的初始运行点附近不同运行点注入下模型的可达性格纳姆矩阵元素近乎不变的性质,将基于K-中心点算法的同调识别和初加速度法相结合,快速识别初始运行点附近的失稳模态,为实用动态安全域(PDSR)直接法提供了临界点搜索建议,改善了PDSR法。该方法的有效性在New England 10机39节点系统得到了验证。

电力系统实用动态安全域的降维与还原

提出了一种在注入功率空间中求取电力系统实用动态安全域(PDSR)的超平面形式的临界稳定边界的新方法。通过对电力系统进行数值仿真搜索到大量临界点,并通过最小二乘法拟合得到临界超平面的方法精确但费时,难以实际应用。为了在重要的预想事故下快速、准确地求取电力系统的临界超平面,文中提出首先将高维的电力系统通过基于相关的动态等值化简为低维的等值系统,再对其进行数值仿真,拟合出等值系统的临界超平面,然后根据动态等值逆过程推导出超平面还原的解析表达式,最后修正还原得到超平面的系数,使所得到的超平面通过一个由对原系统的详细模型进行仿真得到的临界点,可以在一定程度上改善临界超平面的精度。算例结果证明这种方法兼顾了临界超平面求取的速度与精度,使PDSR在实时安全性分析中的应用更易实现。

长链非编码RNA MALAT1在大肠癌中的表达及其临床意义:基于多基因表达数据库分析

背景结直肠癌(colorectal cancer, CRC)是临床中最为常见的消化系统恶性肿瘤,近年来长链非编码RNA(longchainnon-coding RNA, LncRNA)在CRC发生、发展及侵袭转移中发挥重要作用. MALAT1为新近发现的LncRNA,其在CRC中的作用及与患者预后的关系并不十分清楚.目的应用生物信息数据挖掘技术探讨LncRNA MALAT1在大肠癌中的差异表达及其临床意义.方法应用BioGPS数据库分析正常肠上皮中MALAT1的表达情况.在肿瘤芯片表达数据库Oncomine中荟萃分析大肠癌组织与正常肠上皮组织MALAT1的差异表达并分析MALAT1高、低表达与患者生存期是否存在相关性.在STRING数据库中应用蛋白相互作用网络分析与MALAT1相互作用及共表达的相关蛋白.结果MALAT1在正常大肠癌组织中的相对表达量较低.Oncomine数据库中,大肠癌差异表达的研究8项,其中6项在大肠癌中高表达, 2项低表达.比较大肠癌与对应正常组织的相关芯片数据为18个.大肠癌组织中MALAT1表达水平显著高于正常组织(P = 0.027).按结肠癌与直肠癌进亚组分析,结肠癌组织与正常组织MALAT1表达水平无统计学差异(P = 0.149),而直肠癌组织中MALAT1表达水平明显高于对应正常组织(P = 1.04 E-5).在Kaplan-Meier Plotter数据平台中分析MALAT1高、低表达组总生存期分别为41.93mo和52.2 mo,差异无统计学意义(HR = 0.64, 95%CI:0.29-1.39, P = 0.25). String数据库中分析与MALAT1可能相互作用的蛋白,结果显示MALAT1与TP53, SUZ12,CDK4, KDMA,等具有相互作用关系.共表达分析显示MALAT1与EZH2, TP53, SRSF1等基因具有共表达关系,提示这些基因在功能上可能具有相似性.结论大肠癌组织中MALAT1基因表达表达水平明显上调,但MALAT1表达水平与患者预后并无相关性.MALAT1与TP53, SUZ12, CDK4, KDMA蛋白相互作用,上述相互作用蛋白包括多梳蛋白家族,周期蛋白依赖性蛋白激酶等,与肿瘤的基因表达、转录调控及细胞分裂有关.

天然气压缩机仿真测试平台的设计

结合榆林站天然气压缩机组实际运行工况,在Uni Sim仿真平台上搭建以压缩机为核心设备的虚拟工厂,使该仿真平台与西门子的控制系统软件PCS7建立通讯,组成天然气压缩机仿真测试平台。通过操控虚拟工厂或改变虚拟设备的设定参数,模拟天然气压缩机不同运行工况下的机组状态,从而实现对改造后的控制系统进行逻辑验证、性能测试和人员培训。

Neuroprotectants attenuate hypobaric hypoxia-induced brain injuries in cynomolgus monkeys

Hypobaric hypoxia (HH) exposure can cause serious brain injury as well as life-threatening cerebral edema in severe cases. Previous studies on the mechanisms of HH-induced brain injury have been conducted primarily using non-primate animal models that are genetically distant to humans, thus hindering the development of disease treatment. Here, we report that cynomolgus monkeys (Macaca fascicularis) exposed to acute HH developed human-like HH syndrome involving severe brain injury and abnormal behavior. Transcriptome profiling of white blood cells and brain tissue from monkeys exposed to increasing altitude revealed the central role of the HIF-1 and other novel signaling pathways, such as the vitamin D receptor (VDR) signaling pathway, in co-regulating HH-induced inflammation processes. We also observed profound transcriptomic alterations in brains after exposure to acute HH, including the activation of angiogenesis and impairment of aerobic respiration and protein folding processes, which likely underlie the pathological effects of HH-induced brain injury. Administration of progesterone (PROG) and steroid neuroprotectant 5α-androst-3β,5,6β-triol (TRIOL) significantly attenuated brain injuries and rescued the transcriptomic changes induced by acute HH. Functional investigation of the affected genes suggested that these two neuroprotectants protect the brain by targeting different pathways, with PROG enhancing erythropoiesis and TRIOL suppressing glutamate-induced excitotoxicity. Thus, this study advances our understanding of the pathology induced by acute HH and provides potential compounds for the development of neuroprotectant drugs for therapeutic treatment.

Discrete Particle Simulation of Gas-Solid Flow in Air-Blowing Seed Metering Device

In this paper,the gas and seed flow characters in the air-blowing seed metering device are investigated by using the coupled computational fluid dynamics and discrete element method(CFD-DEM)in three dimensions(3D).The method of establishing boundary model based on the computer-aided design(CAD)drawing,has been used to build the boundary model of seed metering device.The 3D laser scanning technique and multi-element method are adopted to establish the particle model.Through a combined numerical and experimental effort,using 3D CFD-DEM software,which is based on the in-house codes,the mechanisms governing the gas and solid dynamic behaviors in the seed metering device have been studied.The gas velocity field and the effect of different rotational speeds and air pressures on the seeding performance and particle velocity have been studied,similar agreements between numerical and experimental results are gained.This reveals that the 3D CFD-DEM model established is able to predict the performance of the air-blowing seed metering device.It can be used to design and optimize the air-blowing seed metering device and other similar agriculture devices.

Joint Optimization of Satisfaction Index and Spectrum Efficiency with Cache Restricted for Resource Allocation in Multi-Beam Satellite Systems

Dynamic resource allocation(DRA) is a key technology to improve system performances in GEO multi-beam satellite systems. And, since the cache resource on the satellite is very valuable and limited, DRA problem under restricted cache resources is also an important issue to be studied. This paper mainly investigates the DRA problem of carrier resources under certain cache constraints. What's more, with the aim to satisfy all users' traffic demands as more as possible, and to maximize the utilization of the bandwidth, we formulate a multi-objective optimization problem(MOP) where the satisfaction index and the spectrum efficiency are jointly optimized. A modified strategy SA-NSGAII which combines simulated annealing(SA) and non-dominated sorted genetic algorithm-II(NSGAII) is proposed to approximate the Pareto solution to this MOP problem. Simulation results show the effectiveness of the proposed algorithm in terms of satisfaction index, spectrum efficiency, occupied cache, and etc.

Enhancement of spatial resolution of ghost imaging via localizing and thresholding

In ghost imaging, an illumination light is split into test and reference beams which pass through two different optical systems respectively and an image is constructed with the second-order correlation between the two light beams. Since both light beams are diffracted when passing through the optical systems, the spatial resolution of ghost imaging is in general lower than that of a corresponding conventional imaging system. When Gaussian-shaped light spots are used to illuminate an object, randomly scanning across the object plane, in the ghost imaging scheme, we show th√at by localizing central positions of the spots of the reference light beam, the resolution can be increased by a factor of 2^(1/2) same as that of the corresponding conventional imaging system. We also find that the resolution can be further enhanced by setting an appropriate threshold to the bucket measurement of ghost imaging.

Genomic Epidemiology of ST34 Monophasic Salmonella enterica Serovar Typhimurium from Clinical Patients from 2008 to 2017 in Henan,China

Salmonella enterica serovar 4,[5],12:i:-(S.4,[5],12:i:-)is a monophasic variant of Salmonella enterica serovar Typhimurium that has emerged as a global serovar causing public health concern.To date,the epidemiology and genomic characterization of this pathogen in China have not been well described.We investigated the prevalence,antimicrobial resistance(AMR)phenotypes,and population genomics of sequence type 34(ST34)S.4,[5],12:i:-among cases of human salmonellosis in Henan Province,China.A total of 100 ST34 S.4,[5],12:i:-isolates were studied from 2008 to 2017 and found mostly resistant to ampicillin(AMP),streptomycin(STR),sulfonamides(SUL),and tetracycline(TET)(ASSu T).Bayesian phylogenetic analysis demonstrated that isolates identified in China were mostly related to the European lineage and evolved into two major clades with different resistance genes and plasmid profiles.Notably,clade 1 showed a significantly higher rate of mutations in gyr A and plasmid-mediated quinolone resistance genes.The carrying of the resistance-containing region(encoding R-type ASSu T),including bla(conferring resistance to AMP),str AB(STR),sul2(SUL),and tet(B)(TET)inserted into the flj BA operon,was responsible for most of the monophasic variants in clade 2.Inc HI2 plasmids were the dominant multi-drug resistance mobile genetic elements accounting for the transmission of acquired resistance genes in this serovar,and these were more prevalent in clade 1.Our findings highlighted the increasing prevalence of multi-drug resistant S.4,[5],12:i:-in China,along with the differential characteristics of resistance gene acquisition among various lineages.Based on our data,control measures are required to address the spread of this zoonotic pathogen.Further owing to its potential origin in food-producing animals,a"One Health"approach,should be implemented to support surveillance whilst informing interventional strategies.

Responsiveness and minimal clinically important difference of the Chinese version of the Low Vision Quality of Life Questionnaire after cataract surgery

AIM: To investigate the Chinese version of the Low Vision Quality of Life Questionnaire(CLVQOL) as an instrument for obtaining clinically important changes after cataract surgery.METHODS: Patients underwent cataract surgery in Shanghai General Hospital, Shanghai Jiao Tong University, who fit the inclusion criteria were recruited. Two CLVQOLs were administered, including a preoperative CLVQOL and a CLVQOL at the end of the 3 mo follow-up period, and were completed using face-to-face interviews or phone interviews conducted by trained investigators. The minimal clinically important difference(MCID) was calculated using an anchor-based method and a distribution method. In addition, the responsiveness of the questionnaire was measured.RESULTS: A total of 155 residents were enrolled. The average visual acuity(VA) preoperatively was 0.08(SD=0.05), and it increased to 0.47(SD=0.28) at the end of followup. Statistically significant positive changes in the CLVQOL scores indicated significant improvement of vision related quality of life after cataract surgery. With the larger value between the two results as the final value, the MCID values of the CLVQOL(scores of the four scales as well as the total score) were 8.94, 2.61, 4.34, 3.10 and 17.63, respectively. The CLVQOL has both good internal and external responsiveness.CONCLUSION: CLVQOL scores are appropriate instruments for obtaining clinically important changes after cataract surgery. This study is an effective exploration for establishingcataract surgery efficacy standards, which helps clinical and scientific research workers in ophthalmology to gain a more in-depth understanding when using CLVQOL.