多孔薄壁扁管连续挤压模的研制

介绍了连续挤压模的生产工艺过程 ,模具主要结构及设计参数 ,分析了生产中存在的问题以及采取的措施 ,充分发挥了连续挤压设备的潜力 ,扩大了产品品种     

20CrMnTi螺旋锥齿轮中出现圆鼓泡问题的分析

在对机车转向架螺旋锥齿轮的粗、精加工中发现其表面鼓起许多小泡，将其剖开酸洗后呈现为小裂纹状，该现象在实际生产中较为罕见，对此进行分析，探讨，查找原因，确定这是钢材内气泡未能焊合的结果，为此制定了改进措施。     

亭子口水电站跌坎消力池减压模型试验研究

采用1:40减压模型,通过测试流态、水下噪声和脉动压力等水力参数,对亭子口水电站闸墩尾部跌坎式底流消力池的空化空蚀特性进行了研究。成果表明：闸墩尾部区域存在强度为发展阶段的剪切流空化,采用8.00 m高度的跌坎消力池后,消力池底板空蚀破坏的可能性较小;但消力池边墙与闸墩内壁侧扩距离较小时,边墙空蚀破坏的可能性较大;消力池边墙与闸墩内壁侧扩距离增至4.20 m时,边墙空蚀破坏的可能性显著降低。     

Microalgae-Based Biohybrid Microrobot for Accelerated Diabetic Wound Healing

A variety of wound healing platforms have been proposed to alleviate the hypoxic condition and/or to modulate the immune responses for the treatment of chronic wounds in diabetes. However, these platforms with the passive diffusion of therapeutic agents through the blood clot result in the relatively low delivery efficiency into the deep wound site. Here, a microalgae-based biohybrid microrobot for accelerated diabetic wound healing is developed. The biohybrid microrobot autonomously moves at velocity of 33.3 µm s⁻¹ and generates oxygen for the alleviation of hypoxic condition. In addition, the microrobot efficiently bound with inflammatory chemokines of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) for modulating the immune responses. The enhanced penetration of microrobot is corroborated by measuring fibrin clots in biomimetic wound using microfluidic devices and the enhanced retention of microrobot is confirmed in the real wounded mouse skin tissue. After deposition on the chronic wound in diabetic mice without wound dressing, the wounds treated with microrobots are completely healed after 9 days with the significant decrease of inflammatory cytokines below 31% of the control level and the upregulated angiogenesis above 20 times of CD31⁺ cells. These results confirm the feasibility of microrobots as a next-generation platform for diabetic wound healing.     

超低碳钢夹杂物控制技术探讨

本文综述了超低碳钢的夹杂物起源,并以日本等先进钢厂的实践经验为基础,对Al2O3夹杂物的产生的工艺过程、影响因素重点进行了讨论,包括渣钢间二次氧化行为、RH处理中夹杂物行为、夹杂物的上浮行为以及铸坯的皮下气泡等.钢包渣改质是控制二次氧化的重要手段,RH加铝前自由氧含量尽可能降低,将浇铸时的氩气量降低均为控制超低碳钢的Al2O3类夹杂物的有效措施.     

Bubble Formation through Reaction at Liquid‐Liquid Interfaces

Slag foaming is an important phenomenon in steelmaking processes with both beneficial as well as negative effects. The present work is part of the wider project on the modelling of slag foaming, with special reference to dynamic conditions. Since bubble formation is the first step to foam formation, the present work was carried out in an attempt to simulate the bubble formation in slag/metal reactions in steelmaking processes by water‐modelling experiments. The bubble formation due to the gas produced through chemical reaction at the interface between oleic acid and sodium bicarbonate solution was systematically monitored. The chemical reaction rate was varied by varying the concentration of sodium bicarbonate. The bubbles were observed to be generated in the heavier aqueous phase just below the water‐oil interface. The bubbles penetrated the interface and escaped through the oil phase. The rate of the reaction was estimated from the volume of the gas that passed the water/oil interface. It was observed that the bubble formation and bubble growth mechanism were influenced by the reaction rate while the bubble size seemed to be unaffected by the reaction rate.     

钢包内气泡行为的数值模拟

气泡行为是钢水精炼过程中最重要的现象之一,用数值方法计算气泡在钢液中的运动,运用拉格朗日法跟踪气泡的运动轨迹,且应用四阶龙格库塔法求解气泡的速度变化,气泡的长大过程.     

流动沸腾条件下窄通道内的汽泡生长和冷凝

针对过冷沸腾条件下窄通道内的汽泡生长和冷凝进行实验研究。实验中观察到了两类汽泡的生长和冷凝,分别称为第1类汽泡和第2类汽泡。其中第1类汽泡生长速度较快,且在滑移离开核化点之后迅速冷凝消失。而第2类汽泡的生长速度较慢,且滑移很长一段距离后也不会冷凝消失,具有更长的存活时间。两类汽泡的生长可采用不同的关系式进行预测,且生长冷凝特性均表现出很强的随机性,体现出汽泡周围环境的微小变化对汽泡行为的影响。     

贫化电炉气液混合顶吹的气泡群形态及搅拌效果

针对贫化电炉还原油枪中气、油混合顶吹对渣层搅拌效果的研究,等比例制作贫化电炉水模型,进行气液混合喷吹实验。实验结果表明：顶吹气液两相混合射流在熔池中形成大小不一的气泡或气泡群,气泡本身的形变、破裂以及气泡间的团聚运动决定了油枪对熔池的搅拌效果。通过测量不同流量下气泡群尺寸的变化,分析气液流量混合比对熔池搅拌效果的影响。     

Biomimetic Engineering of a Scavenger‐Free Nitric Oxide‐Generating/Delivering System to Enhance Radiation Therapy

Nitric oxide (NO) is a potent tumor‐cell radiosensitizer but it can be readily scavenged by hemoglobin (Hb) in vivo. A biomimetic incubator that can generate and deliver NO in a scavenger (Hb)‐free environment to enhance its radiosensitizing effect to maximize its efficacy in radiotherapy is proposed. This NO incubator comprises a poly(lactic‐co‐glycolic acid) (PLGA) hollow microsphere (HM) that contains an NO donor (NONOate) and a surfactant molecule (sodium caprate, SC) in its aqueous core. In acidic tumorous environments, the PLGA shell of the HM allows the penetration of protons from the outside, activating the hydrolytic cleavage of NONOate, spontaneously generating NO bubbles, which are immediately trapped/stabilized by SC. The SC‐stabilized NO bubbles in the HM are then squeezed through the spaces of its PLGA matrices by the elevated internal pressure. Upon leaving the HM, the entrapped NO molecules may passively diffuse through their SC‐stabilized/protected layer gradually to the tumor site, having a long‐lasting radiosensitizing effect and inhibiting tumor growth. The entire process of NO generation and delivery is conducted in a scavenger (Hb)‐free environment, mimicking the development of young ovoviviparous fish inside their mothers' bodies in the absence of predators before birth.