飞机灵活温度减推力起飞技术设计与应用

为了提高发动机的使用寿命、降低维护成本,以达到提高飞机训练和投送经济性的目的,参考民航设计规范和要求,确定了一型飞机的灵活温度减推力起飞的设计原则,提出了一种采用灵活温度方式的减推力起飞技术在该飞机上的具体设计和实施方案,该方案能够从飞行员对发动机实际工作状态的掌控、起飞性能余度等方面,最大限度地保障起飞安全性。根据该机的典型使用场景,对该飞机在日常运输任务的起飞重量下实施灵活温度减推力起飞时的实际起飞性能进行了分析。根据分析结果,该飞机在日常运输剖面的起飞重量下,在某海平面高度机场、温度T 0下起飞时,允许设定的最大灵活温度值为(T 0+20)℃,此时实际起飞性能较最低安全要求仍有一定的余量,能够保证起飞安全,此时对应的起飞推力减小至最大值的85%,用于日常运输时可以使发动机寿命延长约13%。研究结果对灵活温度起飞技术在国内飞机上的设计和应用具有较高的工程参考价值。

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

Design of A Hydraulic Power Take-off System for the Wave Energy Device with An Inverse Pendulum

This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.

Capture Performance of A Multi-Freedom Wave Energy Converter with Different Power Take-off Systems

Among the wave energy converters (WECs), oscillating buoy is a promising type for wave energy development in offshore area. Conventional single-freedom oscillating buoy WECs with linear power take-off (PTO) system are less efficient under off-resonance conditions and have a narrow power capture bandwidth. Thus, a multi-freedom WEC with a nonlinear PTO system is proposed. This study examines a multi-freedom WEC with 3 degrees of freedom: surge, heave and pitch. Three different PTO systems (velocity-square, snap through, and constant PTO systems) and a traditional linear PTO system are applied to the WEC. A time-domain model is established using linear potential theory and Cummins equation. The kinematic equation is numerically calculated with the fourth-order Runge–Kutta method. The optimal average output power of the PTO systems in all degrees of freedom are obtained and compared. Other parameters of snap through PTO are also discussed in detail. Results show that according to the power capture performance, the order of the PTO systems from the best to worst is snap through PTO, constant PTO, linear PTO and velocity-square PTO. The resonant frequency of the WEC can be adjusted to the incident wave frequency by choosing specific parameters of the snap through PTO. Adding more DOFs can make the WEC get a better power performance in more wave frequencies. Both the above two methods can raise the WEC’s power capture performance significantly.

Problems and Barriers Impeding the Implementation of MagLev Assisted Aircraft Take-Off and Landing Concept

Nowadays, the success of the new technology development and deployment process depends not only on technical, technological solutions, but also on solving the non-technological problems and crossing the societal and psychological barriers. A large international European projects, GABRIEL1 had developed a maglev assisted aircraft take-off and landing, that was applied to conceptual design of aircraft and required on-board and ground systems, had analysed all impacts (effects of concept deployment on effectiveness, safety, security, noise, emissions) and had demonstrated the safe applicability by concept validation. The applied methodology, used methods and the results of the Gabriel projects had been described and discussed by 55 project deliverables. This paper has a special goal: investigating the problems and barriers of possible implementing of the radically new technology, aircraft MagLev assisted take-off and landing. The study was started by identification and classification of the problems and barriers. After it, the problems were systematically analysed by use of special methodology containing the understanding (description) of the problems, investigation of the possible solutions and discussing their applicability (mainly by use of the Gabriel project results). The paper has three major sections: 1) description of the Gabriel concept and project results, 2) introducing some related thoughts on general aspects of new technology developments, and 3) discussion on the problems and their solutions. The major classes of the problems are the 1) technical, technological problems as developing a radically new solution, landing the undercarriage-less aircraft on the magnetic tracks, 2) stakeholders’ problems as decision makers kicking against supporting the developments of so radically new technologies and 3) society barriers like society worrying on and fear of future passengers on flying by aircraft have not conventional undercarriage systems. The paper will show that these problems have safe and cost-effective solutions.

Research of Power Take-off System for “Sharp Eagle Ⅱ” Wave Energy Converter

The " Sharp Eagle” device is a wave energy converter of a hinged double floating body. The wave-absorbing floating body hinges on the semi-submerged floating body structure. Under the action of wave, the wave-absorbing floating body rotates around the hinge point, and the wave energy can be converted into kinetic energy. In this paper, the power take-off system of " Sharp Eagle Ⅱ” wave energy converter (the second generation of " Sharp Eagle”) was studied, which adopts the hydraulic type power take-off system. The 0-1 power generation mode was applied in this system to make the " Sharp Eagle Ⅱ” operate under various wave conditions. The principle of power generation was introduced in detail, and the power take-off system was simulated. Three groups of different movement period inputs were used to simulate three kinds of wave conditions, and the simulation results were obtained under three different working conditions. In addition, the prototype of " Sharp Eagle Ⅱ” wave energy converter was tested on land and in real sea conditions. The experimental data have been collected, and the experimental data and simulation results were compared and validated. This work has laid a foundation for the design and application of the following " Sharp Eagle” series of devices.

Power Absorption of A Two-Body Heaving Wave Energy Converter Considering Different Control and Power Take-off Systems

This study proposed a wave power system with two coaxial floating cylinders of different diameters and drafts.Wavebob’s conceptual design has been adopted in the wave power system.In this study,a basic analysis of the wave energy extraction by the relative motion between two floats is presented.The maximum power absorption was studied theoretically under regular wave conditions,and the effects of both linear and constant damping forces on the power take-off(PTO)were investigated.A set of dynamic equations describing the floats’displacement under regular waves and different PTOs are established.A time-domain numerical model is developed,considering the PTO parameter and viscous damping,and the optimal PTO damping and output power are obtained.With the analysis of estimating the maximum power absorption,a new estimation method called Power Capture Function(PCF)is proposed and constructed,which can be used to predict the power capture under both linear and constant PTO forces.Based on this,energy extraction is analyzed and optimized.Finally,the performance characteristics of the two-body power system are concluded.

The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance;a Case Study of the Abeid Amani Karume International Airport-Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA);however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated;i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft;ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories;however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temperatures. Therefore, the study concludes that the changing climate has significantly affected aircraft by increasing the TODR and decreasing the MTOM, while the climate variability has significantly affected landing performance by influencing the diversion and missed approach events. Thus, the study recommends (i) further research works including the feasibility study on runway extension for the safety of future aircraft operations at the AAKIA and (ii) proper maintenance and improvement of the Instrumental Landing Systems (ILS) as an adaptation measures to the landing aircraft during bad weather events.

Hydraulic Power Take-off and Buoy Geometries Charac-terisation for a Wave Energy Converter

In the past few decades, world energy consumption grew considerably. Regarding this fact, wave energy should not be discarded as a valid alternative for the production of electricity. Devices suitable to harness this kind of renewable energy source and turn it into electricity are not yet commercially competitive. The work described in this paper aims to contribute to this field of research. It is focused on the design and construction of robust, simple and affordable hydraulic Power Take-Off using hydraulic commercial components.

REWARDING COOPERATION BETWEEN CAS AND YUNNAN TRIGGERS A SOCIO-ECONOMIC TAKE-OFF

Ⅰ. THE SUGGESTION OF THE STRATEGIC MEASURE Situated at the junction between the vast Eurasian landmass and the south Asian subcontinent, Yunnan Prov-

组合式输尿管软镜一期治疗双侧<1.5cm肾结石的安全性及有效性分析

目的评价组合式输尿管软镜钬激光碎石术一期治疗双侧<1.5 cm肾结石的安全性及有效性。方法回顾性分析2014年8月-2016年3月采用组合式输尿管软镜一期治疗的双侧<1.5 cm肾结石24例患者的临床资料,分析手术时间、结石清除率及并发症发生情况。结果该组24例患者均一期顺利置入双侧输尿管软镜鞘,并顺利进镜碎石,手术时间40~105(71.0±21.5)min,碎石成功率为100.00%,1个月结石清除率为89.58%(43/48),5侧结石残留直径7~10 mm,给予体外冲击波碎石,3个月结石清除率93.75%(45/48),3侧残余结石5~7 mm,且位于下盏,定期复查。术后发热4例,抗炎治疗好转,术中无大出血、输尿管穿孔和撕脱等并发症,术后无肾功能不全、无感染性休克发生。结论组合式输尿管软镜碎石术可一期治疗双侧<1.5 cm肾结石,具有安全、有效的优势。

输尿管软镜与微通道经皮肾镜在输尿管上段结石治疗中的对比研究

目的 通过对输尿管软镜与微通道经皮肾镜碎石术（mini-PCNL）治疗输尿管上段结石的对比研究,探讨两种术式的安全性及有效性.方法 选取该院2012年12月-2014年12月60例输尿管上段结石患者为研究对象.按入院病历单双号分为奇、偶数,奇数为输尿管软镜组（A组）,偶数为mini-PCNL（B组）.右侧28例,左侧32例,结石直径为0.9～2.0 cm,平均（1.50±0.25） cm;比较两组患者手术时间、术中出血量、结石清除率及并发症.结果 该研究60例手术均成功完成,手术时间分别为A组（86.50±12.81） min、B组（81.83±12.76） min,差异无统计学意义（P＞0.05）.出血量分别为A组（2.20±0.58） ml、B组（12.53±2.12） ml,A组明显低于B组,差异有统计学意义（P＜0.05）.术后即刻清石率,A组90.00％（27/30）、B组96.67％（29/30）,1个月结石清除率分别为A组100.00％（30/30）、B组100.00％（30/30）,两组间差异无统计学意义（P＞0.05）.两组均无大出血、严重感染和输尿管损伤等并发症.结论 输尿管软镜碎石术治疗输尿管上段结石较mini-PCNL操作简单、创伤更小、更安全和疗效确切,是目前治疗输尿管上段结石较理想的手术方式,值得临床进一步推广应用.

高分子量聚对二氧环己酮改进聚DL-乳酸柔韧性的研究

为了提高DL-聚乳酸(PDLLA)的柔韧性,将10～20wt%不同比例的由本课题组自主合成的高分子量聚对二氧环己酮(PPDO)加入到PDLLA基体中,对共混物的微观两相形态、力学性能、热学性能和表面性质、降解性能等物化性质进行了研究。实验结果表明,PPDO加入后,在PDLLA/PPDO共混物的柔韧性得到显著提高的同时,共混物表面亲水性相应提高,降解速率也随之加快。

挠盘式栽植器的运动分析与设计准则

根据挠盘式栽植器的工作原理,分析了挠盘式栽植器挠盘的运动轨迹,提出了挠盘夹持点运动特征参数iλ≥1是挠盘式栽植器设计的基本依据和正常工作的必要条件;探讨了苗体在输送带和挠盘之间的传递条件,得出了夹持角β<90°是合适的投苗区间;推算出了拖拉机前进速度、输送带秧槽间距、输送带速度和栽植株距之间的关系表达式。

抗蛇行减振器安装刚度对弹性构架车辆动力学性能影响

基于减振器简化等效模型分析了某动车组车辆系统动力学性能随抗蛇行减振器安装刚度不同的变化情况,并且比较了考虑构架结构弹性振动对这种变化的影响。结果表明,抗蛇行减振器安装刚度对车辆系统动力学性能具有一定影响,尤其是当车辆运行速度达到250 km/h时影响较大;此外,构架的弹性振动也影响着抗蛇行减振器安装刚度的选择。

输尿管负压吸引鞘在输尿管软镜碎石术中的价值探讨

目的探讨输尿管负压吸引鞘在输尿管软镜碎石术治疗肾结石中的安全性及有效性。方法回顾性分析96例行输尿管软镜碎石术治疗肾结石患者的临床资料,应用输尿管负压吸引鞘46例(治疗组),未应用50例(对照组),比较两组患者的结石清除率、手术时间、肾盂内压、术后肾绞痛、石街形成情况、术后全身炎症反应综合征(SIRS)、降钙素原(PCT)浓度、白细胞计数、住院时间、住院费用和治疗有效率。结果治疗组肾盂内压在最小值、最大值和平均值方面均明显小于对照组(P<0.05);在1个月后检查发现,对照组患者治疗有效率为70.0%,清除率为82.0%,而治疗组患者治疗有效率为84.7%,清除率95.6%,治疗组患者结石治疗有效率和清除率明显优于对照组(P<0.05);治疗组和对照组手术时间分别为(86.3±5.2)和(108.6±3.5)min,治疗组明显短于对照组(P<0.05);对照组和治疗组术后肾绞痛例数分别为13和2例(P<0.05);对照组和治疗组术后石街形成例数分别为11和2例(P<0.05);对照组和治疗组术后SIRS分别为10和2例,治疗组术后肾绞痛和石街形成、SIRS例数均明显低于对照组(P<0.05);对照组和治疗组住院时间分别为(8.8±1.1)和(7.7±1.2)d,住院费用分别为(23 067.5±392.8)和(21 957.3±378.6)元,治疗组住院时间和住院费用与对照组比较差异无统计学意义(P>0.05);对照组和治疗组术后PCT分别为(1.5±0.3)和(0.3±0.1)ng/ml,白细胞计数分别为(14.6±0.5)×109/L和(6.4±0.6)×109/L,术后治疗组患者PCT和白细胞计数明显低于对照组(P<0.05)。结论输尿管负压吸引鞘在输尿管软镜碎石术治疗肾结石中安全、有效,缩短手术时长,同时提高结石清除率,减少不良反应发生,应当推广。

输尿管软镜碎石术围手术期肾彩色多普勒超声血流动力学评价

目的 彩用彩色多普勒超声(CDFI)对单发肾结石患者输尿管软镜碎石术围手术期肾血流动力学的评价。方法 分析2016年7月至2018年6月共61例输尿管软镜碎石手术的单发肾结石患者,应用CDFI观察围手术期术侧肾叶间动脉血流参数,记录术前1 d、术后1 h内及术后5 d叶间动脉血流参数,并进行统计学分析。结果 围手术期肾叶间动脉血流参数整体分析,收缩期峰值流速(Vmax)、舒张末期流速(Vmin)及阻力指数(RI)数值差异分别具有统计学意义(P<0.05)。与术前血流参数相比,术后1h叶间动脉Vmax及Vmin均减低,RI增高(P<0.017),术后5 d复查,Vmax及Vmin较术后1 h升高、RI较术后1 h减低(P<0.017),与术前测值相比差异无统计学意义(P>0.017)。结论 CDFI可以观察并量化输尿管软镜碎石术围手术期肾内动脉灌注,快速评价术侧肾血流动力学变化,手术后会出现短期、可逆性肾叶间动脉流速减低、RI增高。

纳米石墨化碳在锂离子电池中的应用进展

纳米石墨化碳因其优异的导电、导热及力学性能近年来备受重视,并在锂离子电池体系中得到广泛运用。纳米石墨化碳具有的优异电学性能及纳米尺度结构特征使其在解决锂离子电池中高导电性、导热性、充放电过程中的柔性及结构稳定性等方面发挥了重要作用。本文综述了近年来纳米石墨化碳在锂离子电池应用中的最新进展和研究热点,包括纳米石墨化碳在锂离子电池中直接充当高容量负极材料,纳米石墨化碳作为高性能骨架材料为电极提供导电及力学网络,与硅、金属氧化物等高容量电极材料复合形成同轴、核壳等结构的高容量电极材料甚至柔性电极等。如何进一步认识纳米石墨化碳储锂机制,发展其精确可控制备科学和工程技术,进而在三维尺度上构建高效的锂离子电池电极材料结构仍是未来的重点研究方向。

基于ADAMS和ANSYS的高速冲床导轨仿真分析

高速精密数控冲床导轨可靠性关系到整机的动态精度和加工质量,通过对高速冲床传动系统曲柄滑块机构进行运动学分析,同时运用SOLIDWORKS软件建立机构的简化模型,并导入ADAMS软件中施加约束、驱动和冲击载荷,然后进行运动学仿真验证计算的准确性;再运用ANSYS软件对导轨进行柔性体转换,之S后对曲柄滑块机构进行柔性体动力学仿真,获取导轨在实际加工过程中的载荷谱、实体应力分布和柔性变形量,为机床可靠性设计分析和寿命预测的准确性提供了必要的基础。

地市级可再生资源能源利用优化

对地市级可再生能源管理问题,建立了在确保有限的传统能源和可再生能源能满足地区各个部门在规划期内的能源总需求条件下,使整个系统的运作成本最低的可再生能源利用优化模型,并根据实际情况假设模型中除太阳能和风能的可利用量为随机变量外,其他参数均为区间数时,利用处理区间数的可能度方法和满意度方法推导该类问题的确定性等价模型.