微波和黄金微针治疗腋臭的临床疗效比较

目的 比较微波和黄金微针治疗腋臭的临床疗效及安全性.方法 2018年5月至2019年3月在第四军医大学西京医院皮肤科门诊收集不同程度的腋臭患者116例,分别用miraDry微波仪(56例)和黄金微针(60例)治疗,术后随访12个月,观察临床疗效、并发症和复发率.结果 经12个月随访,微波组有效率为94.64％(53例)...     

仿生脉冲电磁场对大鼠骨密度下降预防治疗作用的实验研究

目的观察仿生脉冲电磁场（bionics pulsed electromagnetic fields,BEMF）对Wistar大鼠骨质疏松发生的预防性治疗作用。方法本实验取32只3月龄雌性Wistar大鼠,随机分成4组：正常对照组（A组）8只,地塞米松组（B组）8只,降钙素组（C组）8只,电磁场组（D组）8只。A组常规喂养,同时给予注射等量生理盐水;B组仅给予地塞米松肌肉注射（1mg/kg,2次/w）,C组及D组在给予地塞米松（1mg/kg,2次/w）肌肉注射的同时分别给予降钙素皮下注射（2IU/kg,1次/d）及电磁场照射（1h/1次,1次/d）预防性治疗,以上各组均分别于第4、8、12周不同时间点在麻醉状态下测取腰椎及股骨的骨密度值,以观察各不同时间点各组大鼠骨密度的改变。结果BEMF预防性治疗4周,各组大鼠骨密度无显著性差异（P〉0.05）;8周D组较B组骨密度高（P〈0.01）,12周D组较B组骨密度高（P〈0.01）,D组较C组股骨骨密度亦显著增高（P〈0.05）。结论BEMF有预防骨质疏松发生的作用,并随着预防治疗时间的延长,BEMF的预防作用较降钙素有更显著的效果。     

Behavior of Mold Electromagnetic Stirring for Round Bloom Castings and Its Eccentric Stirring Problem

In this paper, a mold electromagnetic stirring (M-EMS) model was established to investigate the behavior of M-EMS for round bloom castings under different conditions, and an electromagnetic-flow-heat transfer-solidification coupling model was established to explore the problem of eccentric stirring for various formats of round blooms. The results show that the magnetic flux density decreased with the increase in the current frequency, but the electromagnetic torque increases first and then decreases with it, and the same structure of M-EMS for round blooms has the same optimal current frequency at any current intensity. The electromagnetic torque and electromagnetic force both increase as a quadratic function of the current intensity, and the electromagnetic torque, which drives the steel flow, can directly characterize the real M-EMS performance. The mold copper tube has a significant magnetic shielding effect on M-EMS, the stirring intensity decreases rapidly as the tube thickness increases, and the optimal stirring frequency decreases as well. In fact, the deviation between the stirrer center and the geometric center of the strand can result in the eccentric stirring phenomenon. When blooms with a section size of Φ350 mm are produced by Φ650 mm SMS-Concast casting machine, the upper region of the inner arc side and the lower region of the outer arc side are subject to a stronger washing effect, which makes the temperature of the inner and outer arcs show alternating differences. The jet flow from the five-port nozzle can suppress the difference in initial solidification symmetry between the inner and outer arcs of round blooms caused by eccentric stirring. This paper reveals the magnetic shielding effect of the mold copper tube and the magnetic field loss of the air between the stirrer and the inner and outer arcs of the copper, which lead to the stirring intensity and the eccentric stirring phenomenon.     

Highly accurate retinotopic maps of the physiological blind spot in human visual cortex

The physiological blind spot is a naturally occurring scotoma corresponding with the optic disc in the retina of each eye. Even during monocular viewing, observers are usually oblivious to the scotoma, in part because the visual system extrapolates information from the surrounding area. Unfortunately, studying this visual field region with neuroimaging has proven difficult, as it occupies only a small part of retinotopic cortex. Here, we used functional magnetic resonance imaging and a novel data‐driven method for mapping the retinotopic organization in and around the blind spot representation in V1. Our approach allowed for highly accurate reconstructions of the extent of an observer’s blind spot, and out‐performed conventional model‐based analyses. This method opens exciting opportunities to study the plasticity of receptive fields after visual field loss, and our data add to evidence suggesting that the neural circuitry responsible for impressions of perceptual completion across the physiological blind spot most likely involves regions of extrastriate cortex—beyond V1.     

生物3D打印的研究进展

3D打印技术是基于计算机三维数字成像技术及多层次连续打印的一种新兴应用技术。生物3D打印技术则是基于3D打印的基础上,以活细胞为原料结合生物材料、生命体材料的拓展延伸,打印活体组织与器官的一种技术。生物3D打印技术已在再生医学及器官移植方面取得了一定的成果,被应用于骨骼、皮肤、人造血管、心脏组织等再生与重建领域。本文主要从生物3D打印技术的方式及特点,生物3D打印技术的研究现状与应用,生物3D打印的发展前景的展望等几个方面进行简要的综述。     

视野半侧缺损的原发性开角型青光眼视网膜微循环改变的研究

目的:研究视野半侧缺损的原发性开角型青光眼（POAG）视盘旁和黄斑区血管密度的改变及其与视网膜神经纤维层（RNFL）厚度及视野指标的关系。方法:横断面研究。收集2015年10月至2018年10月于复旦大学附属眼耳鼻喉科医院眼科应用Humphery视野计30-2程序检测为视野半侧缺损的POAG患者（POAG组）28例（2...     

某部密闭舱室军事作业环境和人员健康调查评价

目的 评价特殊军事作业人工环境影响因素特征及其对人员健康的影响,为进一步开展控制措施的研究提供依据.方法 采用电磁辐射场强仪、声级计、温湿度计、风速仪、一氧化碳检测仪和二氧化碳分析仪,分别对某部军事作业密闭环境的微波辐射、噪声、温度、湿度、风速、一氧化碳和二氧化碳进行监测分析;采用自觉症状问卷,调查评价作业人员健康...     

电磁场促进骨折愈合的研究进展

目的:探讨电磁场促进骨折愈合的研究进展。方法:阅读、研究国内外有关文献并进行综述。结果与结论:从实验研究、临床应用及作用机理3方面证实电磁场对骨折愈合有促进作用。     

Effects of Electromagnetic Fields on the Microstructure of Laser Cladding

The fast heating and quenching of laser cladding increase the internal stresses in the cladding layer. Moreover, the quick condensation of the molten pool leads to an uneven distribution of the internal elements and coarse grains of the structure. To address the above defects and increase the molding quality of laser cladding, an electromagnetic field was introduced into the laser cladding technique, and the effects of the external assisted electromagnetic field on the mixed metal fluid in the molten pool were explored. On this basis, the action of the electromagnetic field on the flow states of the molten pool was further analyzed. The results demonstrate that after introducing electromagnetic assistance, the material flow in the molten pool accelerated as a response to the periodic changes in electromagnetic forces and the influences of the electromagnetic field on crystallization, thus refining the grains and improving the grain distribution uniformity in the cladding layer. The dendritic crystals in the cladding layer decreased, while the isometric crystals and the cellular-like dendrites increased. The element distribution in the cladding layer increased in uniformity. Additionally, this method can decrease the dilution rate of the cladding layer and improve its overall hardness. A laser-cladding test of the Ni-based powder was carried out on the AISI 1045 steel surface under the coaxial powder-feeding mode. Moreover, the influences of the electromagnetic field on the microstructure of the laser-cladding layer were compared, and the causes of the changes were disclosed.     

Development of a Flexible Metamaterial Film with High EM Wave Absorptivity by Numerical and Experimental Methods

The present study is intended to develop and test a cost-effective and efficient printing method for fabricating flexible metamaterial film with high electromagnetic wave absorptivity. The film can be easily applied to the surfaces with curved aspects. Firstly, numerical parametric study of the absorption characteristics of the film is performed for the range of frequency varying from 2.0 to 9.0 GHz based on commercial software package. Secondly, the flexible metamaterial films are fabricated, and experiments are conducted. The flexible metamaterial film consists of a flexible dielectric film made of polyimide (PI) and an array of split-ring resonators. The split-ring resonators of different geometric dimensions are fabricated on the PI film surface by using a silver nanoparticles ink jet printer. The performance of the flexible structure is then measured and dependence of operation frequency with higher absorptivity on the dimensions of the split-ring resonators is investigated. A comparison between the numerical and experimental data shows that the numerical predictions of the operation frequency with higher absorptivity closely agree with the experimental data.