Exploration on Ecological Restoration Model for the Improvement of Ecosystem Services of Yellow River Floodplains —A Case Study of Zhengzhou Yellow River Floodplain Park Planning and Design

The Yellow River Basin is one of the greatest and most important ecological barrier and economic belt in China. When the Yellow River Basin is seen as an ecosystem in whole, the floodplains in the lower reaches are critical to the basin’s health and biodiversity. However, due to the extreme complexity of the natural environment of the floodplains, current flood control policies, long-term agricultural activities, and extensive rural construction and production dikes, the river ecosystem has suffered from considerable damage and a serious decline of ecosystem services. In the planning and design project of the Zhengzhou Yellow River Floodplain Park, the characteristics of the lower, intermediate, and higher floodplains have been carefully identified, site-specific ecological restoration measures for each floodplain type were implemented, highlighting the authenticity and natural qualities and improving the overall ecosystem services. In addition, a slow traffic system and innovative industries along the Yellow River are introduced to enable high-quality cultural perception and recreational experience of the improved ecosystem services, promote green production and lifestyle. These measures help make the Yellow River a river that truly benefit the locals. In the context of ecological protection and high-quality development of the Yellow River, as a national agenda, the ecological restoration planning strategies proposed in this article provides a reference for the development of ecological management and green economy in other sections of the lower reaches of the Yellow River.     

自动称过冲现象分析及其抑制

本文对自动称的过冲现象做了详细的分析说明,并提出了具体的解决方法,对从事自动称的设计、调试及使用人员有一定的参考价值。     

Influence of surface martensite layer on hydrogen embrittlement of Fe-Mn-C-Mo steels in wet H2S environment

This study investigated the effect of thermally induced surface martensite layer on hydrogen embrittlement of Fe-16Mn-0.4C-2Mo (wt.%) (16Mn) and Fe-25Mn-0.4C-2Mo (wt.%) (25Mn) steels through slow strain rate stress corrosion cracking testing and proof ring testing in wet H₂S environment. The 16Mn steel had a surface layer of less than 150 μm in depth containing ε-martensite, α′-martensite and austenitic twins. The martensite layer is found to reduce the hydrogen embrittlement resistance of the steel. In comparison, the 25Mn steel developed a full α′-martensite surface layer, which exhibited practically nil effect on the hydrogen embrittlement resistance of the steel. The ε-martensite provides much larger interface areas with the mechanical twins of the austenite in the 16Mn steel than the α′-martensite/austenite interfaces in the 25Mn steel. These interfaces are hydrogen trapping sites and are prone to initiate surface cracks, as observed in the scanning electron microscope. The formation of the cracks is attributed to hydrogen concentration at the ε-martensite and austenitic twin interfaces, which accelerates material fracture.     

Multi-Objective Optimization of Slow Moving Inventory System Using Cuckoo Search

This paper focuses on the development of a multi-objective lot size–reorder point backorder inventory model for a slow moving item. The three objectives are the minimization of (1) the total annual relevant cost, (2) the expected number of stocked out units incurred annually and (3) the expected frequency of stockout occasions annually. Laplace distribution is used to model the variability of lead time demand. The multi-objective Cuckoo Search (MOCS) algorithm is proposed to solve the model. Pareto curves are generated between cost and service levels for decision-makers. A numerical problem is considered on a slow moving item to illustrate the results. Furthermore, the performance of the MOCS algorithm is evaluated in comparison to multi-objective particle swarm optimization (MOPSO) using metrics, such as error ratio, maximum spread and spacing.     

DP980冷轧高强钢连续退火工艺及强韧性行为研究

采用连续退火模拟试验机研究了连续退火工艺中缓冷及过时效温度对DP980冷轧高强钢组织性能的影响规律,并利用扫描电镜、透射电镜及拉伸试验机进行了显微组织及力学性能检测。研究结果表明：缓冷温度降低有利于新生铁素体及富碳岛状马氏体的生成,且实验钢屈服强度基本不变,抗拉强度先下降后升高,伸长率逐渐上升。缓冷温度为650 ℃时,强塑积（PSE）达到最大值15.55 GPa·%。随着过时效温度的升高,实验钢抗拉强度及屈服强度略有下降,断后伸长率显著升高。工业试制HC550/980DP成品的屈服强度不小于570 MPa,抗拉强度不小于1 080 MPa,伸长率不小于7%,达到应用标准。     

缓/控释肥对小麦增产与提高氮肥利用率的效果研究

以不施氮肥、尿素基施和尿素基追比5∶5等3个处理做对照,对3种包膜缓/控释肥处理冬小麦产量、产量相关因子、不同时期植株含氮量及肥料利用率进行了分析比较。结果表明,缓/控释肥处理的以上几个指标均接近于尿素基追比5∶5处理。与尿素基施相比,包膜缓/控释肥增产10.03%~11.17%,有效穗数和穗粒数增加,返青-拔节期植株含氮量明显提高,氮肥利用率提高了6.18%~11.57%。3种缓/控释肥相比较,产量、产量因子、植株含氮量及肥料利用率没有显著性差异。     

矩形螺旋线慢波电路高频特性的数值分析

介绍了用ANSOFT公司提供的HFSS 10.0软件模拟计算色散特性和耦合阻抗的理论方法,并对矩形螺旋线慢波结构的高频特性进行了数值模拟.结果表明:和传统的圆螺旋线结构相比,矩形结构具有更高的耦合阻抗,能有效减小器件体积;在横截面厚度和螺旋角一定的情况下,当矩形螺旋线的宽高比大于4时,相速几乎不变,但是耦合阻抗随着宽度的增加而下降;同时螺旋角的减小可以降低系统的相速,减小工作电压.由于可利用微电子机械系统(MEMS)印制技术制作,具有可与带状电子束作用,提高效率等优点,矩形螺旋线在紧凑型行波管(TWT)领域有广阔的应用前景.     

Effect of high-pressure hydrogen environment in elastic and plastic deformation regions on slow strain rate tensile tests for iron-based superalloy A286

To investigate the effects of a high-pressure hydrogen environment in the elastic and plastic deformation regions, we performed slow strain-rate tensile tests of iron-based superalloy A286 at 150 °C by switching the atmosphere from 70 MPa hydrogen to air during the tests. The relationship between the nominal strain exposed to a hydrogen environment and the relative reduction in area (RRA) revealed that in the plastic deformation region, the RRA value decreased gradually depending on the nominal strain exposed to hydrogen, but in the elastic deformation region, the RRA value decreased rapidly. The RRA value further decreased when the stress cycle was applid in the elastic region. The fracture surface exhibited an intragranular slip plane fracture similar to that of the hydrogen-charged specimen. These phenomena suggest that the lattice decohesion theory is dominant in the elastic region, where hydrogen embrittlement occurs owing to an increase in the content of dissolved hydrogen.     

Energy consumption mode identification and monitoring method of process industry system under unstable working conditions

Process industry systems under unstable working conditions are prone to potential anomalies, deviating from the original transition trajectory, and taking longer than expected to return to stability due to persistent disturbances from uncertainties and experience-based regulation errors. The energy waste caused by this situation has not received sufficient attention, and cannot be addressed by existing energy consumption monitoring methods. Herein, an energy consumption mode (ECM) identification and monitoring method under unstable working conditions is proposed, consisting of ECM identification model and multi-mode dynamic monitoring model, focusing on the variation rules of the correlation between energy consumption and other states of the system. In the ECM identification stage, the ECM correlation parameters that reflect the comprehensive production information are selected. Then, given the transfer characteristics of ECM, a Hidden Semi-Markov Model (HSMM) is constructed to fit the migration between modes and the duration within modes. The Variational Bayesian Gaussian Mixture Model is introduced to improve the HSMM, which solves the problem of lacking prior knowledge of ECM and achieves the automatic classification and online identification of ECM. In the dynamic monitoring stage of multi-ECMs, a series of dynamic kernel principle component analysis models are established, and the corresponding monitoring thresholds are set for each ECM. By calculating the maximum of the posteriori probability and the mode thresholds, the ECMs under unstable conditions can be accurately identified and automatically monitored. Compared with previous methods, the proposed method reduces the false detection rate and missed detection rate of abnormal ECM identification to 1.04% and 1.31% in the actual slag grinding production process, which proves its effectiveness.     

Crack growth rate in hydrogen pre-charged martensitic steels during slow strain rate tests

Crack growth rate in two high strength martensitic steels with the Mo contents of 0.43 wt.% and 1.06 wt.% was investigated by means of slow strain rate tests (SSRT) on compact tensile specimens after hydrogen pre-charging. It was found that the crack growth rate increased and the values of stress intensity factors K_IH and K_Imax decreased with the increase of pre-charged hydrogen concentration. The steel with higher Mo content showed much lower crack growth rate than the steel with lower Mo content. It could be attributed to more nano-sized precipitates that can act as the hydrogen trapping sites and mitigate hydrogen deleterious effects on crack growth rate and the K_IH and K_Imax values.