High-gain planar TEM horn antenna fed by balanced microstrip line

A printed TEM horn antenna with high gain fed by balanced microstrip line is proposed. The radiation part of the antenna consists of two symmetrical triangular metal slice branches printed on the FR-4 substrate with 15 mm thickness. The two branches are fed by balanced microstrip line. The antenna is simulated by software CST MICROWAVE STUDIO and the equivalent adopted dipole model is proposed to describe the radiation characteristic of the antenna. The simulation results indicate that the frequency range is from 164 GHz to 5 GHz with reflection coefficient less than -6 dB, and the typical gain value is 8 dB in the operating bandwidth. In order to improve antenna gain without influencing the bandwidth, the length of the dielectric slab should be extended appropriately in the main radiation direction. By extending the length of the dielectric slab appropriately in the main radiation direction, the antenna gain can be improved significantly without the influence on the bandwidth. Besides, a metal disc loaded in the radiation direction makes the gain in band be more stable. The prototype has been fabricated and measured in microwave anechoic chamber which is coincident with the simulation results. This antenna can be widely applied in the UWB field.

Glacier mass balance in High Mountain Asia inferred from a GRACE release-6 gravity solution for the period 2002–2016

We provide estimates of glacier mass changes in the High Mountain Asia (HMA) area from April2002 to August 2016 by employing a new version of gravity solutions of the Gravity Recovery and ClimateExperiment (GRACE) twin-satellite mission. We find a total mass loss trend of the HMA glaciers at a rateof –22.17 (±1.96) Gt/a. The largest mass loss rates of –7.02 (±0.94) and –6.73 (±0.78) Gt/a are found forthe glaciers in Nyainqentanglha Mountains and Eastern Himalayas, respectively. Although most glaciers inthe HMA area show a mass loss, we find a small glacier mass gain of 1.19 (±0.55) and 0.77 (±0.37) Gt/a inKarakoram Mountains and Western Kunlun Mountains, respectively. There is also a nearly zero massbalance in Pamirs. Our estimates of glacier mass change trends confirm previous results from the analysisof altimetry data of the ICESat (ICE, Cloud and Land Elevation Satellite) and ASTER (AdvancedSpaceborne Thermal Emission and Reflection Radiometer) DEM (Digital Elevation Model) satellites inmost of the selected glacier areas. However, they largely differ to previous GRACE-based studies which weattribute to our different post-processing techniques of the newer GRACE data. In addition, we explicitlyshow regional mass change features for both the interannual glacier mass changes and the 14-a averagedseasonal glacier mass changes. These changes can be explained in parts by total net precipitation (netsnowfall and net rainfall) and net snowfall, but mostly by total net radiation energy when compared to datafrom the ERA5-Land meteorological reanalysis. Moreover, nearly all the non-trend interannual masschanges and most seasonal mass changes can be explained by the total net radiation energy data. The massloss trends could be partly related to a heat effect due to increased net rainfall in Tianshan Mountains, QilianMountains, Nyainqentanglha Mountains and Eastern Himalayas. Our new results for the glacier mass changein this study could help improve the understanding of glacier variation in the HMA area and contribute tothe study of global change. They could also serve the utilization of water resources there and in neighboringareas.

CFD simulation of gas–liquid flow in a high-pressure bubble column with a modified population balance model

In this study,based on the Luo bubble coalescence model,a model correction factor C_e for pressures according to the literature experimental results was introduced in the bubble coalescence efficiency term.Then,a coupled modified population balance model(PBM) with computational fluid dynamics(CFD) was used to simulate a high-pressure bubble column.The simulation results with and without C_e were compared with the experimental data.The modified CFD-PBM coupled model was used to investigate its applicability to broader experimental conditions.These results showed that the modified CFD-PBM coupled model can predict the hydrodynamic behaviors under various operating conditions.

Spatial variability between glacier mass balance and environmental factors in the High Mountain Asia

High Mountain Asia(HMA) region contains the world’s highest peaks and the largest concentration of glaciers except for the polar regions, making it sensitive to global climate change. In the context of global warming, most glaciers in the HMA show various degrees of negative mass balance,while some show positive or near-neutral balance. Many studies have reported that spatial heterogeneity in glacier mass balance is strongly related to a combination of climate parameters. However, this spatial heterogeneity may vary according to the dynamic patterns of climate change at regional or continental scale. The reasons for this may be related to non-climatic factors. To understand the mechanisms by which spatial heterogeneity forms, it is necessary to establish the relationships between glacier mass balance and environmental factors related to topography and morphology. In this study, climate, topography,morphology, and other environmental factors are investigated. Geodetector and linear regression analysis were used to explore the driving factors of spatial variability of glacier mass balance in the HMA by using elevation change data during 2000–2016. The results show that the coverage of supraglacial debris is an essential factor affecting the spatial heterogeneity of glacier mass balance, followed by climatic factors and topographic factors, especially the median elevation and slope in the HMA. There are some differences among mountain regions and the explanatory power of climatic factors on the spatial differentiation of glacier mass balance in each mountain region is weak, indicating that climatic background of each mountain region is similar. Therefore, under similar climatic backgrounds, the median elevation and slope are most correlated with glacier mass balance. The interaction of various factors is enhanced, but no unified interaction factor plays a primary role. Topographic and morphological factors also control the spatial heterogeneity of glacier mass balance by influencing its sensitivity to climate change. In conclusion,geodetector method provides an objective framework for revealing the factors controlling glacier mass balance.

Optimization of Anti-Collapse Drilling Fluid Systems with High Potassium Content

The ash mudstone in some oil formations is highly water-sensitive.The oil formation is fractured,and the risk of well leakage and collapse is not negligible.This study presents a countermeasure for well collapse prevention,based on a“force-chemistry synergistic balance”approach and the utilization of environmentally friendly and efficient hydration inhibitors.The relevance of this approach is demonstrated considering a drilling fluid system with the high potassium content.The analysis shows that the system can maintain good rheological properties,filtration loss and suspension stability even after aging at 130℃ for 16 h.The primary roll recovery of rock chips is better than 98%.The secondary rolling recovery rate is 89%.The rapid water loss is close to zero.The effects of carrying rock,sand,hydration inhibition and dispersion of drill chips are all noticeable.

A STUDY ON MASS BALANCE OF HIGH ASIAN GLACIERS

Glaciers play an important role in the global water cycling especially in the balance of fresh water on our planet, which exhibits a significant impact on global changes. This paper describes the role of glaciers in the water cycle and global changes and that of High Asian glaciers and their fluctuations, and introduces the global monitoring project on glacier mass balance and the progress in corresponding research in China.

新质生产力的时代内涵、战略价值与实现路径

加快形成新质生产力,是新时代背景下中国经济社会发展从传统要素驱动向创新驱动转型,提升生产效率和质量,促进经济增长持续健康发展,把握新工业革命浪潮,构筑新竞争优势、赢得发展主动权的题中应有之义。本文明确新质生产力的概念及内涵,揭示其理论逻辑、战略价值和实现路径。结合新质生产力的提出背景与相关论述,文章认为新质生产力必须具有“科技创新驱动”“产业高效低耗和环境可持续”“高品质生活和社会服务均等化”“数字赋能”和“国家治理能力现代化”等特征。解构改革开放以来中国新质生产力发展所积累的物质技术基础和政策环境保障,对比分析中国与全球主要国家数字经济发展水平与高科技产品的出口现状,以客观把握中国新质生产力的发展优势与不足。分析在内部面临产业升级滞后与创新能力不足、资源与环境约束、区域城乡发展不平衡、人口结构老龄化与劳动力成本上升、政府治理效率还需提升等“中等收入陷阱”的挑战,外部遭受贸易争端、技术封锁、人权和意识形态威胁、国家领土争端等“修昔底德陷阱”的压力下,新质生产力破解经济高质量发展难题的战略指导意义。进一步地,指出新质生产力的提升是实现国家安全的重要基础,为国家提供了强大的安全保障,有助于构建坚固的国家安全体系。在此基础上,国家安全稳定也是发展新质生产力的必要条件,两者相得益彰。最后,提出为发展新质生产力,尤其注重新质生产力的均衡布局;从内部加强自我建设,释放新质生产力的发展潜能,破除“中等收入陷阱”魔咒;打造安全稳定的外部环境,给新质生产力的发展提供基础保障,破除“修昔底德陷阱”魔咒,支撑构建强劲有力的“双循环”新发展格局。

高质量发展视域下的中国人口均衡发展

在人口形势发生重要转折性变化之际,高质量发展要求更加重视人口素质,以“提质”替代“增量”,以“人才”替代“人力”,充分发挥凝结在人口自身的素质要素的作用,使更多民众更好地享受高质量发展的成果,享受高品质生活。长期均衡发展是人口发展的主要目标,也是人口高质量发展的内在要求。人口均衡发展不仅体现在人口系统内部要素间的依存制约以及人口系统与社会经济系统之间的协调适应,还体现在代际间的传承永续。年龄结构失衡是当前人口非均衡发展的突出表现,应聚焦结构失衡,弥补制约人口均衡发展的短板;同时充分发挥作为人口结构中坚力量的劳动年龄人口的作用,通过与经济高质量发展相协调以及推动人口均衡分布,促进人口均衡发展,助力实现人口高质量发展。

数字技术赋能城乡义务教育一体化发展路径研究——数字技术促进乡村教育高质量发展

城乡义务教育一体化发展是党中央、国务院促进教育公平和教育事业协调发展的重大决策。2021年底,尽管全国2895个县级行政单位均通过了国家义务教育基本均衡发展督导评估,但是乡村地区仍存在师生流失、学校萎缩、教育教学条件相对滞后、教育资源配置不足等问题。文章通过文献和调查研究,分析了城乡义务教育一体化演进中存在的问题,并在数字技术赋能机理分析的基础上,主要针对城乡义务教育一体化发展中政策落实不到位、教育质量低下、乡村教师专业发展薄弱、工学矛盾和数字鸿沟等根本性问题,从教育数字化政策的顶层设计、结对帮扶、国家和地方中小学智慧教育平台应用、以校为本的教师培训、智能终端和数字化教学辅助工具完善等层面,提出了数字技术赋能城乡义务教育一体化发展的路径。

高地层倾角油藏高低部位油井液量配比研究

在高倾角断块油藏中,受重力作用影响,高、低部位油井开发效果差异大。运用物理模拟实验分析了地层倾角对高、低部位油井开发效果的影响,推导了考虑均衡驱替的水驱断块倾角油藏高、低部位油井产液量配比计算方法,并通过与数值模拟结果对比,验证了油井产液量配比计算方法的准确性。研究发现:随着储层倾角的增加,高部位流线变少、水驱波及区域变小、采出程度变低。随着储层倾角增加,达到均衡动用所需的油井产液量配比(高部位油井产液量与低部位油井产液量比)增加。在相同储层倾角的情况下,随着原油密度和注水强度增加,倾角对达到均衡驱替所需的油井产液量配比的影响变弱,油井产液量配比降低。该研究对高倾角断块油藏均衡开发具有指导意义。

高超声速大动压下整流罩分离测力风洞试验

针对高超声速试验模型整体式整流罩的反推火箭拔罩分离问题,开展了反推火箭喷流模拟方法和风洞测力试验装置设计研究,试验模拟了马赫数5、动压33 kPa时整流罩反推喷流干扰效应和分离距离影响,获得了反推喷流和分离距离影响下的整流罩气动特性。试验研究表明:反推火箭拔罩分离过程中,喷流干扰作用主导了整流罩的气动特性,使得法向力系数、轴向力系数和俯仰力矩系数分别出现了44.5%、32.4%和198.6%的最大变化量;在负迎角下,整流罩压心前移显著,使得静稳定设计的整流罩呈现出静不稳定性,不利于整流罩安全分离;分离距离越大,分离距离变化对整流罩气动特性的影响越弱;将分离初始迎角限定为小的正迎角,整流罩在分离过程中容易保持姿态稳定,有利于整流罩安全分离。

数字经济赋能消费升级:微观机制和关联效应

数字经济发展是高质量建设共同富裕示范区的重要动力。居民消费升级是实现共同富裕目标的重要成果之一。供需双侧在数字化转型的过程中产生新的增量,推动供需双侧实现更高水平的平衡。通过逻辑推演,阐释消费升级是高质量发展实现共同富裕的逻辑终点,是共同富裕实现程度的重要参照;分析数字经济对深化供给侧结构性改革和增加有效需求的驱动作用。通过理论分析,以市场经济一般均衡理论为基础,阐释数字经济在创造新的供需动态平衡,追求市场最优的过程中实现消费升级的微观机制。同时,以浙江省为例进行有限的实证分析,通过灰色关联度分析和中介效应分析验证数字经济赋能下,供需双侧驱动消费升级的路径有效性和存在的阻滞点。

如何优化乡村小规模学校布局

乡村小规模学校布局优化是城乡教育一体化发展的重点和难点,更是确保乡村儿童接受公平优质教育的重要基础。但现实中,小规模学校布局仍存在诸多问题:布局分散程度高;决策中缺少科学的程序和技术;布局规划中学校教育资源不足、弱势学生入学机会不均等;校际空间隔离,跨校资源共享难以稳定持续等。因此,应进一步明确小规模学校布局优化的逻辑理路:以教育规划理论引领布局优化的教育功能发挥;以“公平、效率、质量”框架重构布局规划目标;以“集中+分散”布局结构为乡村振兴奠定教育服务基础;以“入学可达性提升”促进乡村儿童入学机会均等;以资源均衡配置促进城乡学校一体化发展。同时,围绕“空间可达、服务范围、学校规模、校际发展优质均衡程度、能否促进学校传承乡土文化”等维度因地制宜设置学校布局标准,并提供支持性策略,主要包括:综合区位因素,构建小规模学校布局与乡村振兴规划融合系统;以参与式GIS技术为基础,优化学校布局规划程序;强化各级政府责任,妥善处理好布局规划中的伴生问题;共享教育资源,促进小规模学校与县镇学校一体化发展。

高铁内外部效益平衡理论

本文构建高铁内外部效益平衡理论,阐释高铁内外部效益平衡的必然性、必要性及其实现路径。研究认为:高铁内外部效益平衡是高铁可持续发展的重要内涵,应重视密度经济的关键指针作用;高铁内外部效益的不平衡与高铁经济行为主体目标的多元性和不相容相关;高铁内外部效益平衡可通过高铁运输需求增加、铁路产业打破经济垄断和行政垄断引入竞争、构建有责政府广义补贴机制进行动态调整。高铁内外部效益平衡理论对于降低基础设施投资风险,支持经济高质量发展意义明显。

义务教育从基本均衡转向优质均衡的价值基础、逻辑理路和实践路径

着力推进义务教育基本均衡向优质均衡转变,是新时代新征程办好人民满意教育的重要部署之一,需要从价值基础、逻辑理路和实践路径3方面厘清基本均衡和优质均衡,以更好地促进义务教育优质均衡发展。对历史走向的梳理和政策分析表明,义务教育均衡发展的价值起点在于坚持人民立场,要在过程中注重深化义务教育质量的改革,以办好人民满意的教育为落脚点。在基本均衡向优质均衡转变的过程中,以起点公平、过程公平和结果公平3个过程梳理其逻辑理路,首先是要深入贯彻以学生为本的思想,确保受教育权的平等;其次是在过程中要调和教育公平和效率之间错综复杂的关系,推动兼顾效率和公平的特色化发展;最后是关注教育结果公平,让每个孩子都有出彩的机会。在实践逻辑方面,从学校、社会和国家3个不同层面来推动优质均衡发展:简政放权以激发学校办学活力,构建正义的教育问责制以保障社会公平,借鉴国外经验、坚持本土特色以探寻中国式优质均衡的策略和方法。

在发展中推进共同富裕:非均衡系统视角

共同富裕与发展内在联系紧密,两者之间的均衡性关系需要深入探索。非均衡发展强调差异性、特殊性,共同富裕强调共性、一致性。对于特定时空环境(如阶段、周期、区域、群体、领域等)而言,如何通过发展,把差异性、特殊性调整成共性、一致性,以达成共同富裕,是应该重点关注的。也就是说,由非均衡发展达成广义的系统均衡或者动态均衡,构成了共同富裕是否能够实现的关键。大系统的特殊性主要体现在小系统、子系统内,在小系统、子系统内部,这些特殊性表现为小范围的共性。先在小范围内部开始推进共同富裕,再在大范围内拓展衔接;先在小系统内部实现共同富裕,再在更大系统、更高层级系统实现共同富裕。应紧扣发展特殊性和富裕共同性矛盾,在共性基础上,把握个性,夯实共同富裕基础,不断向共同富裕目标迈进。切忌不区分发展类型,忽视发展的特殊性,以理想化的均衡模式推进脱离实际的共同富裕计划。研究的主要创新在于:结合了系统论,深化了非均衡理论分析,提出大系统的特殊性即小系统的共性,从而为共同富裕逐步推开,一部分人先富起来提供了坚实的理论依据。

考虑实时备用率的中长时间尺度新能源发电备用的方法

在新型电力系统中,考虑到中长期时间尺度下新能源出力具有较强规律性,提出了中长时间尺度新能源纳入备用的实时备用率的确定方法。根据实时备用率将新能源可信出力纳入备用,建立多电源电力生产模型。所建模型以生产成本最小为目标函数,考虑电源运行成本、新能源弃电成本、切负荷惩罚成本及机组出力、功率平衡、逻辑变量等约束条件。采用时间迭代将中长时间生产模拟化简为短期优化问题,利用CPLEX求解。以改进IEEE-24节点系统作为算例,优化结果表明新能源电源采用实时备用率的方法纳入备用时,电力系统生产运行总成本更低;新能源渗透率越高,纳入新能源为备用的经济效益越明显;风电和光伏独立确定备用率时,备用成本和污染排放更低。

150MW等级双超汽轮机高压缸前轴封结构优化

150MW等级双超机组为超高温进汽方式,高压缸前轴封漏汽温度较高,若轴封结构设计不当,会导致轴封蒸汽外漏、轴承油中带水、端部汽缸变形、汽封动静碰磨或转子弯曲等安全事故,而且较大的高品质蒸汽泄漏也会影响机组的经济性。通过优化高压缸前轴封结构,对数十种漏汽组合模型进行了计算分析,推荐合理运行方式,解决了端汽封漏汽温度高带来的影响,达到了预期效果,提高了经济性,在同类机组中具有较高的应用推广价值。

义务教育信息化优质均衡发展的系统动力机制研究

从系统视角研究义务教育信息化优质均衡发展的演化规律和驱动力,对优质均衡发展失衡风险的预警和治理具有重要意义。使用系统动力学方法,构建义务教育信息化优质均衡发展仿真模型,结构化分析优质均衡发展的驱动因子和内在动力机制,明确义务教育信息化优质均衡发展的动力和未来趋势。研究表明:义务教育信息化优质均衡发展的动力依次为信息化应用、信息化组织与管理、信息化保障机制、数字化教育资源平台、信息化基础设施,应该提升以教师信息技术应用能力为主的应用性投入,巩固以信息化组织与管理队伍、信息化激励与考评制度建设为主的管理性投入,以及完善以数字化教育资源平台、信息化基础设施建设满意度为主的建设性投入,以此来促进义务教育信息化优质均衡发展。

高质量发展视域下城市群空间网络联系与人口长期均衡发展——基于成渝城市群的实证分析

在人口规模巨大的背景下,促进人口长期均衡发展、深入实施区域协调发展是我国高质量发展的必由之路。采用2006—2020年16个城市的面板数据,使用耦合协调度模型和修正引力模型分别测度成渝城市群16个城市在2006—2020年间的空间网络联系度与人口长期均衡发展水平,运用空间杜宾模型实证分析城市群空间网络联系对人口长期均衡发展的影响及其时空异质性和网络外部效应,发现:(1)城市群空间网络联系可促进本地人口长期均衡发展,但将在周边形成“集聚阴影”,产生不利于周边城市人口长期均衡发展的网络负外部效应。(2)成渝城市群空间网络联系对成都市、重庆市双核心城市以及绵阳市、宜宾市和泸州市三个副中心城市的人口长期均衡发展水平产生促进作用。随着行政级别的提升,城市网络联系逐渐由不利于周边城市人口长期均衡发展的负外部效应转变为促进周边城市人口长期均衡发展的正外部效应。(3)城市空间网络联系所产生的外部效应呈现先负后正,最后趋于收敛的倒S型,且在0-100公里的范围内形成“集聚阴影”,150-200公里范围内为城市网络联系发挥正外部效应的最优半径。(4)科技创新和创业活跃度的提升是城市空间网络联系促进人口长期均衡发展的关键渠道。