科创中国

The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant's thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant's local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc(ASHRAE) Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant's thermal responses, including the skin temperature and the thermal sensation. The skin temperature and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in real life traffic is presented. The investigation result indicates that the skin temperature is a robust index to evaluate the thermal sensation. Applying the skin temperature to designing and controlling parameters of the heating, ventilation and air conditioning(HVAC) system may benefit the thermal comfort and reducing energy consumption.

In the field of aerospace, high-speed trains and automobile, etc, analysis of temperature filed and scuffing failure of tapered roller bearings are more important than ever, and the scuffing failure of elements of such rolling bearings under heavy load and high speed still cannot be effectively predicted yet. A simplified model of tapered roller bearings consisted of one inner raceway, one outer raceway and a tapered roller was established, in which the interaction of several heat sources is ignored. The contact mechanics model, temperature model and model of scuffing failure are synthesized, and the corresponding computer programs are developed to analyze the effects of bearings parameters, different material and operational conditions on thermal performance of bearings, and temperature distribution and the possibility of surface scuffing are obtained. The results show that load, speed, thermal conductivity and tapered roller materials influence temperature rise and scuffing failure of bearings. Ceramic material of tapered roller results in the decrease of scuffing possibility of bearings to a high extent than the conventional rolling bearing steel. Compared with bulk temperature, flash temperature on the surfaces of bearing elements has a little influence on maximum temperature rise of bearing elements. For the rolling bearings operated under high speed and heavy load, this paper proposes a method which can accurately calculate the possibility of scuffing failure of rolling bearings.

报告1例播散型皮肤假性淋巴瘤.患者男,48岁.因躯干及头面部丘疹、结节伴瘙痒3年余就诊.皮损组织病理检查:表皮基本正常,真皮内见致密结节状、以淋巴细胞为主的浸润,还可见嗜酸性粒细胞、浆细胞及组织细胞,淋巴细胞形状大小较为一致,无非典型性核,病变以真皮上半部为主,皮下组织未见异常.免疫组化检查:部分细胞cD4(++),CD8(++),CD3(++),CD45Ro(++),细胞毒颗粒相关蛋白(TIA)-1(+),穿孔素(perforin)(-),CD56(-);少数细胞CD20(++),CD79a(++);S-100蛋白部分(+),CDla部分(+)提示朗格汉斯细胞增生,特殊染色示:结核杆菌及麻风杆菌抗酸染色均(-).诊断:播散型皮肤假性淋巴瘤(以T细胞增生为主).

There is less research on vertical sculptured grinding technology.Especially in high vertical surface grinding process with the cup abrasive wheel,the thermal damage is prone to happen and undermine the grinding surface integrity.This problem limits to improve the grinding efficiency and the grinding ratio greatly.Through the analysis of vertical surface grinding process and features in depth,this paper revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel.Based on the previous research achievements,the grinding experiments on TC4(Ti-6Al-4V)and GH4169 are carried out utilizing the self-inhaling internal cooling wheel.The experimental results show that the self-inhaling internal cooling wheel can efficiently reduce the grinding surface temperature.Moreover,the inherent mechanism of reducing the grinding temperature using the internal cooling method is revealed.Meanwhile,under the same grinding conditions,the grinding ratio during the experiments on GH4169 using self-inhaling internal cooling method is about 3 times as high as using conventional external cooling method.And the grinding forces can be reduced by about 20%.This research revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel,which provides theoretical basis for the design and application of self-inhaling internal cooling wheel.At the same time,an efficient and non-invasive surface grinding method of TC4 and GH4169 is presented.

Many researches on drilling force and temperature have been done with the aim to reduce the labour intensiveness of surgery, avoid unnecessary damage and improve drilling quality. However, there has not been a systematic study of mid- and high-speed drilling under dry and physiological conditions(injection of saline). Furthermore, there is no consensus on optimal drilling parameters. To study these parameters under dry and physiological drilling conditions, pig humerus bones are drilled with medical twist drills operated using a wide range of drilling speeds and feed rates. Drilling force and temperature are measured using a YDZ-II01 W dynamometer and a NEC TVS-500 EX thermal infrared imager, respectively, to evaluate internal bone damage. To evaluate drilling quality, bone debris and hole morphology are observed by SEM(scanning electron microscopy). Changes in drilling force and temperature give similar results during drilling such that the value of each parameter peaks just before the drill penetrates through the osteon of the compact bone into the trabeculae of the spongy bone. Drilling temperatures under physiological conditions are much lower than those observed under dry conditions, while a larger drilling force occurs under physiological conditions than dry conditions. Drilling speed and feed rate have a significant influence on drilling force, temperature, bone debris and hole morphology. The investigation of the effect of drilling force and temperature on internal bone damage reveals that a drilling speed of 4500 r/min and a feed rate of 50 mm/min are recommended for bone drilling under physiological conditions. Drilling quality peaks under these optimal parameter conditions. This paper proposes the optimal drilling parameters under mid- and high-speed surgical drilling, considering internal bone damage and drilling quality, which can be looked as a reference for surgeons performing orthopedic operations.

以某拱坝为例,深入分析了不同固结灌浆阶段拱坝出现裂缝的成因和机理.高温季节控制固结灌浆上抬压力是避免开裂的关键;低温季节固结灌浆时表面温度应力是主导因素,尤其是出现长间歇期时.结合反馈分析与预报仿真结果,提出高温季节固结灌浆时应合理控制盖重厚度、灌浆压力以及灌浆开始的龄期;低温季节固结灌浆时,要做好保温工作.此外还可考虑采用无盖重灌浆来减小长间歇时间.

电机温升对电机的性能有重要影响,是电机设计的关键.基于流体动力学原理,对矿用防爆电机的热流耦合场进行数值计算,得到了电机内部流场特性、电机整体温度分布、电机各部件峰值温度及所在位置.通过方案比较,确定定、转子铁心长度;然后进行结构优化,采用电机内置风扇、定转子铁心增设通风孔两种方法增强电机内部冷却效果,并验证数值计算的可行性.所得结论为电机设计提供了一定的理论参考.

基于计算流体力学(Computational Fluid Dynamics,CFD)通用计算程序Fluent,研究了模块化熔盐冷却球床堆(Pebble Bed Advanced High Temperature Reactor,PB-AHTR)中心热通道稳态热工水力行为.利用已开发的多孔介质流固两相局域非热平衡模型计算了球床堆中的压降、冷却剂的温场分布以及固相球床的温场分布,计算并比较了不同的多孔介质阻力因子(Ergun与KTA)对通道内的冷却剂流动以及温场分布的影响,并对丧失部分冷却剂情况下通道内的冷却剂及燃料温度进行了计算分析.结果表明使用不同的阻力因子对堆芯压降计算结果和流场的分布影响较大:而冷却剂温场及固相球床温场和球心的温度分布在不同的阻力因子下的差别较小,在PB-AHTR的设计参数下堆芯产生的热量能够被有效的输出,设计具有较大的安全裕度.计算结果对于球床堆的优化设计提供了一定的参考价值.

基于室内标定试验得到的混凝土内部温湿度对于钢筋锈蚀速率的影响关系以及现场混凝土内部温湿度的实时监测数据,提出了一种用于实时监测混凝土内钢筋锈蚀速率的新方法,并设计了相关试验进行验证.结果表明:通过该监测方法得到的钢筋锈蚀速率数据能较为可靠地计算钢筋锈蚀量.