履带车辆静态轮荷计算与距地高实现

在履带式车辆总体设计过程中,结合车辆质心位置合理布置行动系统、分配和调整各轮负荷是确保车辆距地高要求准确实现、具有良好静态姿态的前提.本文提出一种计算办法来确保履带式车辆静态距地高的实现,并给出了采用油气弹簧悬挂形式下的计算办法.

GNSS同步法确定验潮站深度基准面大地高研究

为了解决沿海大范围无验潮水深测量中远离海岸的验潮站深度基准面大地高的确定问题,研究基于GNSS PPK和自容式压力验潮仪同步进行潮位观测,获取验潮站深度基准面大地高。构建了基于GNSS同步法确定深度基准面大地高的解算方法,并采用沿岸长期站和短期验潮站进行成果精度检核。结果表明,GNSS同步法确定深度基准面的大地高测量精度优于10cm,精度满足测量规范要求。

变“水低地高”为“水高地低” 重塑黄河上游水土关系

甘肃生态环境脆弱、脱贫攻坚任务重的省情,直接或间接与水土关系的不协调有关,水不养土、土不涵水导致水土流失严重、削弱了土地的生产力,而这一省情的病根源于甘肃特有的地形地貌所决定的水土空间布局,即“水低地高”的基本形态。借鉴我国古代水利工程都江堰将岷江一分为二、造福成都平原人民的奇迹,基于南水北调西线工程新增水量调水线路必经甘肃的实际,提出在刘家峡水库上游海拔1800~1900 m之间将黄河也一分为二,分为自然河道和人工河道,形成弦弧双路循环的格局,其中人工河道即弦线自西南向西北沿海拔1800 m左右的等高线以0.04%左右的比降缓慢自流至景泰台塬地区海拔最高点1773 m处,然后再分几个方向自流灌溉后回归黄河天然河道,从而变“水低地高”为“水高地低”。这一弦弧双路方案的实施,不仅可促进黄河刘家峡至黑山峡之间1万多km2生态脆弱区和石羊河下游的生态保护和高质量发展,也可惠及规划的大柳树灌区,使其成为国家重要的粮食安全储备基地,而且有利于减缓沿黄灌区的盐碱化危害,减轻下游宁蒙河段河道淤积及防洪、防凌压力。

维吾尔族与汉族心力衰竭患者地高辛治疗效果及血药浓度对比观察

目的比较地高辛治疗维吾尔族(以下称维族)、汉族心力衰竭患者的临床效果及血药浓度的差异。方法选取100例维族、100例汉族心力衰竭患者,分别为维族组、汉族组。两组均于心力衰竭常规治疗,在此基础上给予地高辛0.125 mg,1次/d,疗程均为12周。分别检测治疗前后血清BNP、6 min步行试验、左室舒张末内径(LVEDD)、左心室射血分数(LVEF)、HR及地高辛血药浓度(SDC),并观察临床疗效及安全性。结果与治疗前比较,治疗后两组血清BNP、HR、LVEDD降低,6 min步行距离、LVEF增加,P均<0.05;但两组治疗后上述指标及临床疗效比较,P均>0.05。维族组治疗后1、12周SDC明显低于汉族组,P均<0.05;SDC正常范围出现中毒症状8例(维族组6例),高于正常范围未出现中毒症状15例(汉族组11例)。结论地高辛治疗维族及汉族心力衰竭的疗效相当,但维族组SDC显著高于汉族组。

目标等大地高飞行时高度与2D雷达系统误差联合估计

实际应用背景中,许多目标均做等大地高飞行,但飞行高度值未知。探测中高空目标时,2D雷达系统误差估计需要同时对目标高度进行估计。针对这种情形,首先,建立地球球处理模型,并验证这种近似处理模型的可行性;其次提出将目标高度与2D雷达系统误差进行联合估计的思想,并建立ECEF坐标系下的联合估计模型;仿真结果验证该方法的有效性,经过系统误差修正和高度补偿后,各2D雷达探测航迹精度得到大幅提高。

复杂海域高精度海底地形测量关键问题研究

为实现复杂海域高精度海底地形测量,本文研究了软质海底无依托验潮站的布设、远距离GNSS PPK测量,GNSS同步法确定验潮站深度基准面大地高和区域无缝垂直基准的构建等关键问题。以苏北浅滩海域为例,通过一系列关键技术的应用,解决了远距离大范围潮汐复杂海域的高精度海底地形测量问题,实际应用结果表明:基线距离在92 km时,GNSS PPK大地高的解算精度优于10 cm;与GNSS同步法计算出的深度基准面大地高进行对比分析,距离在100 km内,结果互差小于5 cm,两者精度具有一致性;区域无缝垂直基准模型的精度优于5 cm,综合精度优于10 cm。本文提出的方法可以满足远距离复杂海域的高精度海底地形测量的需要。

GPS高程在隧道高程控制中的应用研究

在野外水准控制点遭到破坏,缺乏足够高程数据的情况下进行高程控制测量,可以先布设GPS控制网,GPS控制点应包括稳定的可用高程控制点。然后以一个高程控制点为起算点,实施三角高程闭合水准导线测量,水准路线包含所有的GPS控制点。在小区域范围内,假设该区域高程异常值为常数;从而可以在实施三角高程测量外业时使用高精度的WGS84大地高数据对测量数据进行实时的检核。实践表明:该方法测量精度高且工作效率令人满意,完全能满足山区的工程测量需要。

Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field

Due to the long-term plate tectonic movements in southwestern China,the in-situ stress field in deep formations is complex.When passing through deep soft-rock mass under non-hydrostatic high in-situ stress field,tunnels will suffer serious asymmetric deformation.There is no available support design method for tunnels under such a situation in existing studies to clarify the support time and support stiffness.This study first analyzed the mechanical behavior of tunnels in non-hydrostatic in-situ stress field and derived the theoretical equations of the ground squeezing curve(GSC)and ground loosening curve(GLC).Then,based on the convergence confinement theory,the support design method of deep soft-rock tunnels under non-hydrostatic high in-situ stress field was established considering both squeezing and loosening pressures.In addition,this method can provide the clear support time and support stiffness of the second layer of initial support.The proposed design method was applied to the Wanhe tunnel of the China-Laos railway in China.Monitoring data indicated that the optimal support scheme had a good effect on controlling the tunnel deformation in non-hydrostatic high in-situ stress field.Field applications showed that the secondary lining could be constructed properly.

基于SpringBoot的地方高校软件工程专业建设管理系统的设计与实现

信息技术的飞速发展提升了各行各业的管理运行效率,地方高校专业建设管理也可借鉴。由于整理繁杂的专业建设资源、评估专业成果水平的工作耗时耗力,文章以地方高校软件工程专业为研究对象,以省级特色高水平专业建设要求为目标,以规范管理为目的研发本系统。系统采用SpringBoot、MyBatis-plus作为后台开发框架,模板引擎Beetl进行前端开发,MySQL关系型数据库作为数据持久库,功能涵盖培养模式及目标、教学资源、课程体系建设、师资队伍、教学质量保障、培养效果和产教融合等,既方便整合、检索专业历年来建设资料,也有助于从数据分析角度出发,精准获取专业在人才培养过程中存在的不足,为科学管理和特色发展服务。系统运行稳定、健壮性强,响应时间快,满足设计要求。

高速公路项目地方政府隐性债务风险化解研究

基础设施项目建设从来都是关系国计民生、地方福祉的重大事项,也是支撑地方GDP最主要的来源。各省在全力发展基础设施项目建设的同时,不可避免地会与金融机构产生一定联系。该文以地方高速公路建设项目为例,围绕地高项目融资过程中遇到的融资难问题,地方政府在协助解决融资难问题中向金融机构出具的各种承诺函、说明函等形成的地方政府隐性债务以及如何有效化解地方政府隐性债务进行深入研究。

Design and implementation of low-cost geomagnetic field monitoring equipment for high-density deployment

The observation of geomagnetic field variations is an important approach to studying earthquake precursors.Since 1987,the China Earthquake Administration has explored this seismomagnetic relationship.In particular,they studied local magnetic field anomalies over the Chinese mainland for earthquake prediction.Owing to the years of research on the seismomagnetic relationship,earthquake prediction experts have concluded that the compressive magnetic effect,tectonic magnetic effect,electric magnetic fluid effect,and other factors contribute to preearthquake magnetic anomalies.However,this involves a small magnitude of magnetic field changes.It is difficult to relate them to the abnormal changes of the extremely large magnetic field in regions with extreme earthquakes owing to the high cost of professional geomagnetic equipment,thereby limiting large-scale deployment.Moreover,it is difficult to obtain strong magnetic field changes before an earthquake.The Tianjin Earthquake Agency has developed low-cost geomagnetic field observation equipment through the Beijing–Tianjin–Hebei geomagnetic equipment test project.The new system was used to test the availability of equipment and determine the findings based on big data..

Simulation of Start-Up Process of Turbofan Engine Based on Full-State Characteristics of Fan

Difficulties in obtaining component characteristics in the sub-idle state of rotor constrain the simulation capabilities of ground and windmill start-up processes for turbofan engines.This paper proposes a backbone feature method based on conventional characteristics parameters to derive the full-state characteristics of fan.The application of the fan’s full-state characteristics in component-level model of turbofan engine enables zero-speed iterative simulation for ground start-up process and windmill simulation for windmill start-up process,thereby improving the simulation capability of sub-idle state during turbofan engine start-up.

Climate state of the Three Gorges Region in the Yangtze River basin in 2022–2023

Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.

论创新人才培养及地方高校课程建设

近些年国家不断调整产业结构与经济发展方式,地方高校也在逐渐向应用技术型方向转变,地方高校原有的课程体系难以满足培养创新人才的需求,需要对课程体系进行优化与完善。本文以地方高校为着眼点,阐述如何建设课程体系以培养社会所需的创新人才,提升地方高校的人才培养水平,为社会输送大量高素质的创新人才,推动区域经济发展。

Biomechanical Characteristics of Rape Stalks

[Objective] To study the correlation between the biomechanical properties of rape stalks and rape stem lodging. [Method] Through axial compression tests to the stalks of 4 different rape varieties, the change rules of maximum stem bearing ca- pacity, maximum compressive strength, elastic modulus and moment of inertia along plant height were analyzed, as well as the effect of different varieties and water contents on the biomechanical property indices of rape stalks. [Result] The maximum loads of rape stalks presented liner decrease trend along with the increase of stem height, and all reached the maximums below the height of 50 cm. The maximum stem compressive strength and elastic modulus of the 4 varieties were increased with ascending height, but in a slow rate with small change, thus the modulus of e- lasticity could be considered as unchanged. The maximum bearing capacity, maxi- mum compressive strength and elastic modulus of dry rape stalks were higher than wet stalks, indicating that the water contents of rape stalks had significant effect on their mechanical properties. According to the actual lodging situations in filed, stalks of variety No. 1 owned the worst biomechanical properties and lodging degree, while the biomechanical properties of No. 6 and F5 were better than No. 1 and No. 9, and they also had stronger lodging-resistance. [Conclusion] The study provides parameters and bases for the design of mechanized production and mechanical deep processing of crops, and can better reveal the physical natures of organisms. The methods used in this study can also be used to screen excellent crop stalks.

Effects of Temperature and Nitrogen Input on Nitrogen Mineralization in Alpine Soils on Tibetan Plateau

[Objective] The study aimed to investigate the effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau.[Method]An incubation experiment in the laboratory was conducted using three alpine soils.These soils were collected from the top 10 cm depth in three grassland types：alpine meadow in Haibei,alpine steppe in Naqu and alpine wetland in Dangxiong.[Result] Temperature significantly affected nitrogen mineralization in alpine soils of three grassland types.The mineralization rate in alpine steppe soil rose with the rise of temperature,while the mineralization rate in the alpine meadow soil and alpine wetland soil decreased with the rise of temperature.Nitrogen input had no significant effect on nitrogen mineralization in the alpine meadow soil,but significantly increased nitrogen mineralization in the alpine steppe soil and the alpine wetland soil.Grassland types significantly affected nitrogen mineralization in alpine grasslands.[Conclusion] The effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau were significant.And those different effects depended on different types of grassland.

Effects of Shading Degree on Storage Rate and Growth of Phoebe bournei Seedlings in Fields

In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.

Advances in Grassland Ecosystem Research in Northern Tibetan Plateau

With the aggravation of global change, the response and adaptation of the unique ecosystem in Qinghai-Tibet Plateau to global change have been increasingly concerned by scientific community day by day, which makes the sensitivity and fragility of this ecosystem in response to global change widely recognized by scholars. On the basis of introducing the present research process on the degenerate mechanisim, measures of and approaches to recovery, carbon cycle and primary productivity toward global change, we put forward several propositions on studying the alpine grassland ecosystem in Northern Tibetan Plateau.

Effects of Enhanced Ultraviolet Radiation-B on Maize in Arid Regions of Middle-high Elevation

[Objective] The experiment aimed to explore the influence of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation for correct assessing the influence of enhanced ultraviolet radiation-B on maize and providing scientific reference to make proper countermeasures. [ Method] The location test in field and lift lamp of UV-B were used to observe the changes of maize height, leaf area and number of green leaves under influences of different UV-B radiation. [ Result] In arid regions of middle-high elevation, enhanced ultraviolet radiation-B could dwarf maize plant, decrease leaf area, decline number of green leaves and yield. The reason of decreasing leaf area was that enhanced ultraviolet radiation-B shortened leaf length and leaf width while the reason of declining yield was that yield components were all negatively influ- enced and with the increase of ultraviolet radiation-B, the yield declined dramatically. [ Concluslonl The result of this experiment would be good for maize production in arid regions of middle-high elevation.