基于半静态调度与资源竞争的uRLLC业务时延分析

超可靠低时延通信(ultra Reliable and Low Latency Communication,uRLLC)是未来移动通信中的一种重要应用场景,是工业自动化、智能交通和远程医疗等众多新兴领域的技术基础。重点研究了无线通信系统中uRLLC业务的上行时延。建立了uRLLC业务的上行无线传输系统模型;从初传时延与单次重传时延2个角度分别进行问题建模与业务流时延分析,初传数据包采用半静态调度,重传数据包采用资源竞争调度;推导获得了包含多次重传的uRLLC业务的时延上界以及对应的概率分布。在理论分析的基础上,开发了基于NS3的uRLLC业务传输仿真平台,获得了uRLLC业务时延的仿真结果,并将其与时延上界理论计算结果对比,验证了时延上界理论分析的准确性。

新时代“国培计划”项目实施质量提升策略——以A学院为例

“国培计划”项目实施质量直接关系到教师专业素养,对推动我国教育事业的优质均衡发展具有至关重要的意义。A学院作为一所地方性高校,在“国培计划”实施方面取得了一定的成功经验。但在新时代下,也面临着不少新的困难,表现在国培地位、特色学科、数智化、服务与竞争意识、持续反馈机制等多个方面。对此,A学院可从确保国培的示范和领航地位、打造富有特色的优势学科方向、推动培训和管理工作的数智化、强化国培项目竞争和服务意识、提高国培项目申报的竞争力、完善持续跟踪评价机制等六个方面入手施以改革。

Prediction and quantification of effective gas source rocks in a lacustrine basin:Western Depression in the Liaohe Subbasin,China

Due to limited data on the geochemical properties of natural gas,estimations are needed for the effective gas source rock in evaluating gas potential.However,the pronounced heterogeneity of mudstones in lacustrine successions complicates the prediction of the presence and geochemical characteristics of gas source rocks.In this paper,the Liaohe Subbasin of Northeast China is used as an example to construct a practical methodology for locating effective gas source rocks in typical lacustrine basins.Three types of gas source rocks,microbial,oil-type,and coal-type,were distinguished according to the different genetic types of their natural gas.A practical three-dimensional geological model was developed,refined,and applied to determine the spatial distribution of the mudstones in the Western Depression of the Liaohe Subbasin and to describe the geochemical characteristics(the abundance,type,and maturation levels of the organic matter).Application of the model in the subbasin indicates that the sedimentary facies have led to heterogeneity in the mudstones,particularly with respect to organic matter types.The effective gas source rock model constructed for the Western Depression shows that the upper sequence(SQ2)of the Fourth member(Mbr 4)of the Eocene Shahejie Formation(Fm)and the lower and middle sequences(SQ3 and SQ4)of the Third member(Mbr 3)form the principal gas-generating interval.The total volume of effective gas source rocks is estimated to be 586 km^(3).The effective microbial,oil-type,and coal-type gas source rocks are primarily found in the shallow western slope,the central sags,and the eastern slope of the Western Depression,respectively.This study provides a practical approach for more accurately identifying the occurrence and geochemical characteristics of effective natural gas source rocks,enabling a precise quantitative estimation of natural gas reserves.

Experimental study and numerical simulation of the impact of under-sleeper pads on the dynamic and static mechanical behavior of heavy-haul railway ballast track

Laying the under-sleeper pad(USP)is one of the effective measures commonly used to delay ballast degradation and reduce maintenance workload.To explore the impact of application of the USP on the dynamic and static mechanical behavior of the ballast track in the heavy-haul railway system,numerical simulation models of the ballast bed with USP and without USP are presented in this paper by using the discrete element method(DEM)-multi-flexible body dynamic(MFBD)coupling analysis method.The ballast bed support stiffness test and dynamic displacement tests were carried out on the actual operation of a heavy-haul railway line to verify the validity of the models.The results show that using the USP results in a 43.01%reduction in the ballast bed support stiffness and achieves a more uniform distribution of track loads on the sleepers.It effectively reduces the load borne by the sleeper directly under the wheel load,with a 7.89%reduction in the pressure on the sleeper.Furthermore,the laying of the USP changes the lateral resistance sharing ratio of the ballast bed,significantly reducing the stress level of the ballast bed under train loads,with an average stress reduction of 42.19 kPa.It also reduces the plastic displacement of ballast particles and lowers the peak value of rotational angular velocity by about 50%to 70%,which is conducive to slowing down ballast bed settlement deformation and reducing maintenance costs.In summary,laying the USP has a potential value in enhancing the stability and extending the lifespan of the ballast bed in heavy-haul railway systems.

往复压缩机进气阀气量无级调节技术现状及展望

往复压缩机供气与需求不匹配是导致能耗高的主要原因,进气阀气量无级调节技术是解决该问题的有效手段,其实现方式包括直线网状部分行程顶开式调节系统和旋转杯状全程可控式调节系统。直线网状部分行程顶开式调节系统可以实现对压缩气量的精准连续调节,本质为液压传动控制,但存在通流面积小、阻力损失大、撞击严重、执行系统复杂及故障点多等缺陷。旋转杯状全程可控式调节系统是一种新型气量无级调节技术,其本质为机电一体化,原理是通过伺服电机对杯状阀进行精准调控,具有通流面积大、阻力损失小、开阀无摩擦、关阀摩擦行程小及运动部件无撞击等优点。对2种调节系统的理论、结构、控制系统、能效进行了全面的综述,指出旋转杯状全程可控式调节系统是未来的发展方向,应从旋转杯状全程可控式调节系统的理论研究、结构优化、材料研制及智能系统开发等方面开展深入研究。

Bonding enhancement of cold rolling TA1 P-Ti/AA6061 composite plates via surface oxidation treatment

TA1 P-Ti/AA6061 composite plate was produced by oxidizing the surface of the titanium plate and adopting a cold roll bonding process.The results revealed that the oxide film(Ti6O)prepared on the surface of TA1 pure titanium was easy to crack during the cold roll bonding,thereby promoting the formation of an effective mechanical interlock at the interface,which can effectively reduce the minimum reduction rate of the composite plates produced by cold rolling of titanium and aluminium plates.Moreover,the composite plate subjected to oxidation treatment exhibited high shear strength,particularly at a 43%reduction rate,achieving a commendable value of 117 MPa.Based on oxidation treatment and different reduction rates,the annealed composite plates at temperatures of 400,450,and 500°C displayed favorable resistance to interface delamination,highlighting their remarkable strength-plasticity compatibility as evidenced by a maximum elongation of 31.845%.

Influence of wind-blown sand content on the mechanical quality state of ballast bed in sandy railways

During the operation of sandy railways, the challenge posed by wind-blown sand is a persistent issue. An in-depth study on the influence of wind-blown sand content on the macroscopic and microscopic mechanical properties of the ballast bed is of great significance for understanding the potential problems of sandy railways and proposing reasonable and adequate maintenance and repair strategies. Building upon existing research, this study proposes a new assessment indicator for sand content. Utilizing the discrete element method(DEM) and fully considering the complex interactions between ballast and sand particles, three-dimensional(3D) multi-scale analysis models of sandy ballast beds with different wind-blown sand contents are established and validated through field experiments. The effects of varying wind-blown sand content on the microscopic contact distribution and macroscopic mechanical behavior(such as resistance and support stiffness) of ballast beds are carefully analyzed. The results show that with the increase in sand content, the average contact force and coordination number between ballast particles gradually decrease, and the disparity in contact forces between different layers of the ballast bed diminishes. The longitudinal and lateral resistance of the ballast bed initially decreases and then increases, with a critical point at 10% sand content. At 15% sand content, the lateral resistance is mainly shared by the ballast shoulder. The longitudinal resistance sharing ratio is always the largest on the sleeper side, followed by that at the sleeper bottom, and the smallest on the ballast shoulder. When the sand content exceeds 10%, the contribution of sand particles to stiffness significantly increases, leading to an accelerated growth rate of the overall support stiffness of the ballast bed, which is highly detrimental to the long-term service performance of the ballast bed. In conclusion, it is recommended that maintenance and repair operations should be promptly conducted when the sand content of the ballast bed reaches or exceeds 10%.

Codelivery of anti-CD47 antibody and chlorin e6 using a dual pH-sensitive nanodrug for photodynamic immunotherapy of osteosarcoma

Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.

基于目标检测算法的历史建筑清水砖墙劣化特征智能识别与评估诊断

通过深度学习和计算机视觉技术的融合应用,结合迁移学习优化神经网络架构,基于目标检测算法,实现对历史建筑清水砖墙劣化损伤特征的自动识别及精确评估。建立清水砖墙劣化特征样本数据库,选用PP-PicoDet算法进行模型训练与特征增量叠加训练,实现对损伤类型、位置和程度的快速且精确的自动识别。相较传统人工勘查模式,大幅提高了作业效率及结果准确性,为历史建筑保护修缮提供了新的智能化高效勘察工具和方法。

动力髋螺钉加防旋螺钉及股骨颈系统内固定治疗GardenⅡ-Ⅳ型股骨颈骨折的比较

背景:动力髋螺钉加防旋螺钉内固定治疗股骨颈骨折的生物力学强度高于空心螺钉,但未能体现微创原则;股骨颈系统采用微创手术治疗股骨颈骨折,手术并发症少、术后稳定性强、预后较好,可减少术后内固定失效、骨折移位等并发症的发生率。目的:对比动力髋螺钉加防旋螺钉与股骨颈系统内固定治疗GardenⅡ-Ⅳ型股骨颈骨折的近期疗效。方法:选择贵州省骨科医院2019年1月至2021年2月收治的GardenⅡ-Ⅳ型股骨颈骨折患者,共纳入93例,年龄24-79岁,采用随机数字表法分为对照组(n=43)和试验组(n=50),对照组置入动力髋螺钉加防旋螺钉进行骨折固定与复位,试验组应用股骨颈系统进行骨折固定与复位。记录两组切口大小、出血量、手术时间、透视次数及骨折复位情况。术后随访观察骨折愈合时间、目测类比评分、Harris评分、并发症发生及再次手术情况。结果与结论:①试验组切口长度、出血量、手术时间、透视次数均少于对照组(P<0.05),两组患者骨折复位良好,复位等级比较差异无显著性意义(P>0.05);②两组患者均完成6个月术后随访,两组内固定失败、骨折不愈合、股骨头坏死的发生率比较差异无显著性意义(P>0.05),术后并发症的总发生率、再次手术率比较差异无显著性意义(P>0.05);③两组骨折愈合时间比较差异无显著性意义(P>0.05);两组治疗后6个月的Harris评分、目测类比评分均较治疗前明显改善(P<0.05),两组间治疗后6个月的Harris评分、目测类比评分比较差异均无显著性意义(P>0.05);④结果表明,动力髋螺钉加防旋螺钉与股骨颈系统治疗股骨颈骨折的力学性能均良好,但股骨颈系统内固定的优势体现在操作简便、透视次数少、手术时间短、创伤小、出血量少。

2022 HP special volume:Interdisciplinary high pressure science and technology

High pressure science and technology is a vast area of inter-disciplinary research that encompasses the fields of physics,chem-istry,geoscience,and materials science and in which the science of ordinary matter is only a special case under ambient condi-tions.Pressure,the physical variable of force exerted on the chem-ical bonding of a material,directly controls the material’s phys-ical and chemical properties.

女性艾滋病风险感知及安全套使用相关因素的调查研究

目的全球范围内中老年女性人类免疫缺陷病毒(human immunodeficiency virus,HIV)阳性病例有明显增加趋势。本研究旨调查湖南省40岁及以上女性对HIV感染风险的感知、艾滋病相关知识和态度、安全套使用情况及关联因素。方法2019年7月至2020年8月,对湖南省4个地区的958名40岁及以上女性进行横断面调查。收集其社会人口学特征、HIV感染风险感知、艾滋病知识和态度、安全套使用和其他安全性行为的相关资料。使用单因素和多因素logistic回归分析来确定安全套使用的关联因素。结果在958名调查对象中,60.6%认为自己没有感染艾滋病毒的风险,46.8%报告他们在过去的性生活中从未使用过安全套。年龄较大、家庭月收入较低、在过去1年没有接受过艾滋病相关教育、不愿意使用避孕套或无法在性行为时决定安全套的使用、对艾滋病态度更消极的女性在性行为过程中使用安全套的可能性较小。结论调查显示多数40岁及以上的女性认为自己感染HIV的风险很低,性行为过程中安全套使用率也很低。未来应针对这一群体加强艾滋病预防和控制相关知识教育。

Shape Memory Polymer Composite Booms with Applications in Reel-Type Solar Arrays

Solar arrays are the primary energy source for spacecraft.Although traditional rigid solar arrays improve power supply,the quality increases proportionally.Hence,it is difficult to satisfy the requirements of high-power and low-cost space applications.In this study,a shape-memory polymer composite(SMPC)boom was designed,fabricated,and characterized for flexible reel-type solar arrays.The SMPC boom was fabricated from a smart material,a shape-memory polymer composite,whose mechanical properties were tested.Additionally,a mathematical model of the bending stiffness of the SMPC boom was developed,and the bending and buckling behaviors of the boom were further analyzed using the ABAQUS software.An SMPC boom was fabricated to demonstrate its shape memory characteristics,and the driving force of the booms with varying geometric parameters was investigated.We also designed and manufactured a reel-type solar array based on an SMPC boom and verified its self-deployment capability.The results indicated that the SMPC boom can be used as a deployable unit to roll out flexible solar arrays.

Anisotropy of 2H-NbSe_(2)in the superconducting and charge density wave states

Anisotropy is an important feature of layered materials,and a large anisotropy is usually related to the two-dimensional charac teristics.We investigated the anisotropy of the layered transition metal dicalcogenide 2H-NbSe_(2)in the superconducting and charge density wave(CDW)states using magnetotransport measurements.In the superconducting state,the normalized H_(c2)^(‖c)/H_(p)is independent of the thickness of 2H-NbSe_(2),while H_(c2)^(‖ab)/H_p increases significantly with decreasing thickness,where H_p is the Pauli limiting magnetic field and H_(c2)^(‖c)anu H_(c2)^(‖ab)are the upper critical fields in the c and ab directions,respectively.It is found that the superconducting anisotropy parameterγH_(c2)=H_(c2)^(‖ab)/H_(c2)^(‖c)increases with reduction in the thickness of 2H-NbSe_(2).In the CDW state,the angular(θ)dependence of magnetoresistance,R(H,θ)scales with H(cos^(2)θ+γ_(CDW)^(-2)sin^(2)θ)^(1/2),which decreases with increasing temperature and disappears at about 40 K.It is found that the CDW anisotropy parameterγ_(CDW)is much larger than the effective mass anisotropy but does not change a lot for ultrathin and bulk samples.Our results suggest the existence of three-dimensional superconductivity and quasi-two dimensional CDWs in bulk 2H-NbSe_(2).

Thermal transport properties of two-dimensional boron dichalcogenides from a first-principles and machine learning approach

The investigation of thermal transport is crucial to the thermal management of modern electronic devices.To obtain the thermal conductivity through solution of the Boltzmann transport equation,calculation of the anharmonic interatomic force constants has a high computational cost based on the current method of single-point density functional theory force calculation.The recent suggested machine learning interatomic potentials(MLIPs)method can avoid these huge computational demands.In this work,we study the thermal conductivity of two-dimensional MoS_(2)-like hexagonal boron dichalcogenides(H-B_(2)VI_(2);V I=S,Se,Te)with a combination of MLIPs and the phonon Boltzmann transport equation.The room-temperature thermal conductivity of H-B_(2)S_(2)can reach up to 336 W·m^(-1)·K^(-1),obviously larger than that of H-B_(2)Se_(2)and H-B_(2)Te_(2).This is mainly due to the difference in phonon group velocity.By substituting the different chalcogen elements in the second sublayer,H-B_(2)VIV I′have lower thermal conductivity than H-B_(2)VI_(2).The room-temperature thermal conductivity of B2STe is only 11%of that of H-B_(2)S_(2).This can be explained by comparing phonon group velocity and phonon relaxation time.The MLIP method is proved to be an efficient method for studying the thermal conductivity of materials,and H-B_(2)S_(2)-based nanodevices have excellent thermal conduction.

3D Free-Standing Carbon Nanofibers Modified by Lithiophilic Metals Enabling Dendrite-Free Anodes for Li Metal Batteries

Li metal with high-energy density is considered as the most promising anode for the next-generation rechargeable Li metal batteries;however,the growth of Li dendrites seriously hinders its practical application.Herein,3D free-standing carbon nanofibers modified by lithiophilic metal particles(CNF/Me,Me=Sn,Fe,Co)are obtained in situ by the electrospinning method.Benefiting from the lithophilicity,the CNF/Me composite may effectively prevent the formation of Li dendrites in the Li metal batteries.The optimized CNF/Sn–Li composite electrode exhibits a stable cycle life of over 2350 h during Li plating/stripping.When matched with typical commercial LiFePO_(4)(LFP)cathode,the LFP//CNF/Sn–Li full cell presents a high initial discharge specific capacity of 139 mAh g^(−1)at 1 C,which remains at 146 mAh g^(−1)after 400 cycles.When another state-of-the-art commercial LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM(811))cathode is used,the assembled NCM//CNF/Sn–Li full cell shows a large initial specific discharge capacity of 206 mAh g^(−1)at substantially enhanced 10 C,which keeps at the good capacity of 99 mAh g^(−1)after 300 cycles.These results are greatly superior to the counterparts with Li as the anodes,indicating the great potential for practical utilization of the advanced CNF/Sn–Li electrode.

《小娘惹》在新加坡和中国的生产、传播和接受

2020年版的中国电视剧《小娘惹》受到2008年版的新加坡同名电视剧的影响,沿袭了前者优秀的故事讲述和别具特色的娘惹文化。但由于不同的文化语境,在传播、接受和再生产过程中也存在差异。首先,前者的制作定位是电视艺术精品,后者则按照传奇剧套路改编。其次,同是对于娘惹文化的宣传,但有各自不同的意识形态宣传目的。前者在去属地化和重新属地化的过程中,强调娘惹文化与中华文化的相近与不同,强调新加坡的历史和独特性;后者强调两种文化的相同处和中华根文化。再次,同是对传统文化的叙说,但不同的语境使得前者的文化寻根意识更浓,强调严格遵守儒家文化礼仪,弘扬追远和宽恕精神,提倡集体和家庭意识等传统道德。后者对传统文化的优点有弘扬,但对其糟粕(比如男尊女卑、盲目愚孝)进行了更激烈的批判。可见,电视剧的成功出口仅仅只是掌握流行文化的通行符码还不够,还要在内容上精心打磨,探讨和塑造共通的人性和共同的价值观念。

Mineralogy and element geochemistry of the Sohnari rocks of Early Eocene Laki Formation in the Southern Indus Basin,Pakistan:Implications for paleoclimate,paleoweathering and paleoredox conditions

The Sohnari Member of the Early Eocene Laki Formation is massively deposited in the Southern Indus Basin of Pakistan and is considered a potential source rock to generate hydrocarbons.However,the detailed paleoclimatic,paleoweathering,and depositional conditions of the Sohnari Member have not been studied earlier.This research mainly discusses the detailed mineralogical(bulk and clay)and elemental geochemistry of the Laki Formation from two outcrop sections(Jhimpir and Lakhra)in the Southern Indus Basin,Pakistan.The bulk minerals,including quartz(low),hematite,calcite,halite,gypsum,and clay minerals such as kaolinite,chlorite,smectite and illite have been discussed here.These results demonstrate the paleo-environment of studied area was arid with enhanced saline and weak to strong oxidizing depositional conditions.The chemical index of alteration(CIA)values in Jhimpir and Lakhra sections are in the ranges of 41.30-97.93 and 22.30-96.19,respectively,indicating that the Sohnari sediments experienced weak to intense chemical weathering in the source area.The interpretation of the A-CN-K ternary diagram is consistent with the clay mineral contents in the studied sediments,which is characterized by the predominance of kaolinite,gibbsite and chlorite,demonstrating the weak to strong weathering state under warm and humid climatic conditions.The chemical indices such as Sr/Ba,δU,V/Cr,Ni/Co,and Cu/Zn,U/Th and Ba/Ga show that Sohnari rocks of Early Eocene Laki Formation underwent strong evaporation,oxic water column with warm to humid and minor contact of cold climatic conditions.Based on our present data,it can be concluded that the sediments of Sohnari Member of Laki Formation from Jhimpir and Lakhra areas of Southern Indus Basin in Pakistan are related to Indio-Eurasian collision and came from the Indian shield rocks that were deposited in a brackish water body with a minor contact of the freshwater oxidizing paleo-environment depositional conditions.

静脉输液自动加药混合调配系统在我院静脉用药调配中心的开发与应用

目的:介绍静脉输液自动加药混合调配系统在我院静脉用药调配中心(PIVAS)的开发与应用情况。方法:基于现有的PIVAS条码管理系统,结合自动混合调配设备,我院开发并设计了可实现药品实时扫描计费、混合调配参数设置以及静脉输液自动加药混合调配的静脉输液自动加药混合调配系统。通过与人工调配模式比较,考察5名工作人员共调配注射用复合辅酶、注射用卡络磺钠各300袋静脉输液的加药效率和空瓶内药液残留量,评价该系统的应用效果。结果:该系统实现了静脉输液的自动化混合调配,且在人工调配与系统自动调配模式下,注射用复合辅酶的加药效率分别为(96.6±10.0)、(193.5±20.0)袋/h(P<0.001),空瓶内药液残留量分别为(0.09±0.02)、(0.11±0.01)mL;注射用卡络磺钠的加药效率分别为(83.8±12.9)、(118.8±6.7)袋/h(P<0.001),空瓶内药液残留量分别为(0.08±0.02)、(0.12±0.01)mL;残留量均低于注入溶剂体积不超过5%(≤0.15 mL)的内控标准。结论:我院静脉输液自动加药混合调配系统可提高静脉输液调配工作效率,减少工作人员的强度。

基于实时电价的电动汽车充放电优化策略和经济调度模型

实时电价为优化电动汽车(EV)充放电负荷提供了手段,从而实现经济调度。首先建立用户最优充放电策略模型:以计及EV电池退化成本的用户成本最小为目标,以满足EV行驶荷电状态和充放电荷电状态等为约束。在此基础上建立电动汽车用户实时电价响应模型,通过实时电价计算用户充电成本,使电动汽车充放电负荷与电价联动调整,并将该模型嵌入电动汽车充放电策略优化目标函数。求解过程中,用"停泊时长"确定单车一日可多次充放电的时段和行驶时段,从而在EV可充放电时长范围内优化每时段充放电负荷。最后建立经济调度模型:目标中计及机组阀点效应、约束中考虑EV充放电负荷以及机组爬坡速率等限制的多目标经济调度模型,提出一种改进模式搜索算法求解该时间耦合、非线性、非凸模型。以IEEE 39节点为例,验证了所建立模型和求解算法的有效性。