Application and optimization of frequency converter in the elevator control system

随着现代化城市的高速发展，一幢幢高楼拔地而起，在这些高层建筑中每天都有大量的人和物品需要由电梯来进行垂直输送。在超高层建筑里，电梯的作用在一定程度上比建筑物本身更为重要。随着全国乡镇城市化进程的不断推进，电梯已经走进了大部分人的生活。无论是去商场、超市、酒店、办公楼还是公寓楼都要用到电梯，电梯己经成为人们用的最多的交通工具。正因为如此，电梯的安全性以及舒适感己经成为人们最关心的话题。 此外由于社会经济的快速发展，电梯的在用数量急剧增长，电梯的耗电量巨大。随着国家能源政策对耗能产品提出新的要求，属于建筑中高耗能特种设备的曳引式电梯，其能耗的研究成为电梯能效评价、节能监管、电梯设计、选配电梯的基...With the increasingly rapid development of modernized city, more and more tall buildings are sprawling everywhere. Among these high-rise buildings, a great number of people and goods are vertically conveyored by elevators every day. And in the extra-high building, the role of an elevator is more important than a building itself in a sense. With the continuous advancement of national towns urbaniat...学位：工程硕士院系专业：信息科学与技术学院自动化系_控制工程学号：X200722302

慢性阻塞性肺疾病患者脑灰质密度变化的初步研究

目的利用基于体素的形态测量学(VBM)方法,分析慢性阻塞性肺疾病(COPD)患者脑灰质密度与健康人的差异。方法选取COPD患者18例为COPD组和民族、年龄、性别和教育程度相匹配的16例健康体检者为对照组。比较两组间心肺功能、血气分析指标及日常生活能力(ADL)评分。磁共振成像(MRI)行全脑扫描,运用VBM分析影像数据,比较两组被试脑区灰质密度改变。结果 COPD组1秒最大呼气量、用力肺活量及二者的比值、脉血氧饱和度、血氧分压、及ADL评分明显低于对照组,而脉搏次数及二氧化碳分压均明显高于对照组(P均<0.05)。VBM结果显示,与对照组相比,COPD组的右脑(舌回、中央后回、颞上回、海马旁回、海马、杏仁复合体和扣带前回),左脑(颞下回、颞中回和尾状核),双侧岛叶和双侧丘脑灰质密度均显著降低(P均<0.001)。结论 COPD患者慢性缺氧导致了局部脑灰质密度的降低。局部脑区的损害可能参与了COPD患者病理性心肺功能的调节,并可能与其认知和情绪改变有关

Field map-based rectification of susceptibility distortion and signal compensation in diffusion tensor imaging

目的采用基于体素的场图对磁共振弥散张量成像(diffusion-tensor; imaging,DTI)进行几何变形矫正及信号补偿研究,扩大DTI临床研究及应用价值。材料与方法获取29名健康人脑场图,分别对其DTI进行相位反; 卷积计算及信号校准补偿,将结果配准到3D结构图像。选择对磁场敏感的双侧颅底额叶和颞叶作为观察脑区,对磁场不敏感的丘脑作为对照脑区,对部分各向异性; (fractional; anisotropy,FA)值及信号的差异及其与结构像的形态差异进行统计分析。结果在颅底额叶和颞叶,DTI的磁敏感变形得到了矫正,因场不均性导致; 的信号损失得到了补偿。结论高场中DTI的畸变及体素信号丢失可应用场图的校准得到明显矫正,有利于进一步扩大高场DTI在临床中的应用价值。Objective: This study was designed to employ the voxel-based field map; to rectify the geometric deformation and compensate the signal loss of; diffusion tensor imaging (DTI), and thus facilitate the studies and; clinical applications of DTI. Materials and Methods: Brain field maps; from 29 healthy persons were first used to get B1 field heterogeneous; signals, and then the compensation and phase disconsolation of signals; were performed. Finally, the geometry deformations of DTI were rectified; and registered to 3D images. Magnetic sensitive bilateral temporal lobes; and frontal lobes were selected as regions of interesting and meanwhile,; magnetic insensitive thalamus was selected as control area. Results:; Geometry deformations of DTI produced by different susceptibilities; between specific tissues were completely rectified, and thus the signal; loss was compensated and the accuracy of DTI was significantly enhanced.; Conclusion: Signal compensations and deformation rectifications can be; well achieved using field map, which may improve the applications of DTI; in neurosurgery.国家自然科学基金面上项

Effects of Different Concentrations of Alcohol On Spatial Learning and Memory Ability and Hippocampal GFAP/NEUN in Mice

目的 探究长期饮酒对小鼠行为学能力以及空间学习记忆能力的影响。方法 雄性KM小鼠45只,随机分成对照组（Con）,低剂量组（Low）和高剂量组（High）。分别每天对照组0.10 ml/10 g自来水,低剂量组0.05 ml/10 g的56度红星二锅头,高剂量组0.10 ml/10 g的56度红星二锅头进行灌胃。连续灌胃13 d后进行衣架实验测行为学能力,最后取海马做免疫荧光染色观察海马神经元和星形胶质细胞。结果衣架实验得分,自主活动数值总体显示Low组高于其他两组,而且与Con组差异显著;免疫荧光结果显示无论是CA3区,还是DG区,海马的星形胶质细胞含量与神经元细胞含量比值上Con,Low,High三组依次升高,而且Con,High之间对比,P〈0.05,差异有统计学意义。结论 长期大量饮酒会损伤学习记忆能力,但适量饮酒可以促进机体兴奋性和活动度。Objective To investigated the effects of long-term alcohol drinking on the ability of learning and memory in mice. Methods 45 male KM mice were randomly divided into control group （Con）, low dose group （Low） and high dose group （High）. The control group were daily 0.10 ml/10 g tap water, low dose group 0.05 ml/10 g, 56 degree star erguotou, high dose group 0.10 ml/10 g, 56 degree star Erguotou by intragastric administration. After 13 days of continuous feeding, the experiment was conducted to test the behavior of the horse＇s tail, and the hippocampus was observed by immunofluorescence staining. Results The hanger score, numerical display Low overall locomotor activity was higher than the other two groups, and group Con; immunofluorescence results showed that both the CA3 region or DG region, astrocytes and neurons of hippocampus content ratio on Con, Low, High three group were significantly increased, and Con, High had significant difference, Conclusion A large number of long-term drinking will damage the ability of learning and memory, but moderate alcohol consumption can promote the body excitability and activity

税收优惠对企业全要素生产率的激励作用研究——基于供给侧结构性改革背景

本文在供给侧结构性改革背景下,以税收调查数据为切入点,使用前沿计量方法估计微观企业全要素生产率,发现中国实施供给侧结构性改革后,企业全要素生产率水平得到显著提升,契合了改革的初衷;同时也发现税收优惠对企业全要素生产率水平有正向激励作用,但过度的税收优惠反而会助长企业"惰性",影响其研发和创新的主动性。基于以上研究,本文针对如何提升企业全要素生产率水平提出政策性建议和意见

三学期制运行效果问卷调查与教学建议——以厦门大学为例

自2004年9月厦门大学再次推行三学期制以来,恢复短学期制而进行的改革措施是否达到预期效果,教师和学生对第三学期又有怎样的看法与建议,等等这些一直是教育学界关注和探讨的焦点问题。文章以厦门大学在校师生为主要调查对象,采用问卷访问的形式,总结并剖析了厦门大学第三学期的运行效果,并结合实际提出一些建议,以期对教学改革有所裨益

The morphological study of brain cortical in chronic obstructive pulmonary disease

目的研究应用基于体素的形态学分析(VbM)方法,观察慢性梗阻性肺部病变(COPd)患者的大脑皮质变化。材料与方法搜集在住院中的COPd患者(患者组)25例和年龄、性别、文化背景等相似的志愿者(对照组)25例进行肺功能、精神状态检查及血气分析。二组均行3d T1WI检查,采用VbM、fSl分析软件(簇体积减少>70体素)。应用一般线性模型进行统计学分析,计算两组的全脑灰质总体积,基于体素比较两组全脑灰质各个体素体积的差异。结果COPd患者日常生活活动性、简易精神状态测试、视觉重建及数字记忆测试预测值明显低于正常人。患者额叶的双侧眶回、双侧额下回三角区(brOCA区),以及双额内側回、右侧前岛回及深部核团等局部灰质体积较正常对照组减少(P值均70 voxel).Statistical analysis was performed using the general linear model to detect whole brain gray matter volume differences between the two groups.Results: Compared with the control group, the patients with COPD had markedly lower scores in the activities of daily life, the Mini-Mental State Examination, and Visual Reproduction, and Figure Memory tests.Statistical correlation between two groups showed significant gray matter volume loss in the regions of frontal lobe(bilateral orbital gyros, bilateral inferior frontal gyrus triangle), medial frontal gyrus, right anterior insular gyrus, and deep nuclei(P<0.01).According to the statistics of t value maximum voxels in coordinate of MNI, the Brodmann regions of the brain, which obviously atrophy, were mainly in 47 brain regions(superior frontal gyrus), the bilateral 13 brain regions(insular cortex), 22 brain regions(superior temporal gyrus), bilateral 32 and 24 brain regions.Conclusions: In COPD patients, the cortex volume of multiple brain areas can reduce, the damage regions mainly relate to bilateral prefrontal cortex, medial frontal gyrus, and right anterior insular gyrus.The regions of brain cortex injury are consistent with other diseases, such as obstructive sleep apnea, congenital central expiratory deficiency syndrome, and the cerebral injury of people living in high altitude areas.国家自然科学基金面上项目(编号:31071041

脑型肝豆状核变性脑皮层及皮层下核团体积的磁共振研究

目的探索脑型肝豆状核变性患者脑灰质的损害。材料与方法采集30例初发且未经治疗的脑型肝豆状核变性患者脑3D T1WI图像,利用FSL软件,运用基于体素的形态学测量(voxel_based morphometry,VBM)对脑皮层...国家自然科学基金项目(编号:81671674、81871519)~

The Effects of High-altitude on Human Brain

全世界有大量人群生活在高原上。高原具有低氧、低压、寒冷、强紫外线辐射和湿度低等特殊环境。不同高原人群的低氧适应涉及高原环境与人类进化、遗传、生长发育、生理功能和疾病状态等许多问题。已有的研究在呼吸、心血管和血液系统揭示了高原适应的机制。呼吸和心血管系统受中枢神经系统的调控，它们功能的适应性改变必然反馈作用于脑内调节中枢和相关环路。另一方面，大脑皮质对低氧十分敏感，低氧直接影响脑细胞的代谢，导致结构和功能的改变。然而，目前为止，世居高原人类适应的脑调节机制目前尚不清楚。高原环境脑适应后，它的高级功能的改变也有待阐明。另外，中度海拔是高原人口最密集的地区，每年有许多人到这些地区旅行或工作。因此，了解高原环境低氧对人类认知能力有何影响也显得十分重要。 本研究运用活体结构和功能磁共振成像和分析技术，包括基于像素的形态测量CVoxel-based Morphometry, VBM)、弥散张量成像(Diffusion tensor imaging, DTI )结合定量各向异性分数(fractional anisotropy } FA)的分析、基于血氧水平依赖(BOLD)的任务刺激功能磁共振(fMRI )和静息状态fMRI扫描和细胞活动分析，选择世居海拔2616-4200米高原的汉族人群为研究对象，通过与海平而对照人群比较，对世居高原环境人类脑结构、神经细胞活动和功能连接进行了观察。对世居高原和长期慢性中度海拔高原生活人群的认知能力测试包括长时(内隐和外显)和短时记忆、反应时和视觉空间构建。 结果发现，高原环境适应后脑因灰质丢失而导致局部密度降低。这些区域集中在双侧前额叶、双侧岛叶前下端、右侧扣带前回和枕计卜皮质。通过计算FA值发现，右侧扣带后部FA值显著降低，而双侧内囊前支FA值明显升高。高原人群脑神经细胞在没有任务刺激的静息状态下低频活动的同步性在不同脑区表现增加或降低。通过最大吸气任务刺激的功能磁共振研究发现，与平原对照组比较，呼吸相关中枢岛叶前下端的激活在高原人群显著降低。进一步研究揭示，岛叶前下端与中央前后回皮质的功能连接增强。与平原人群比较，世居高原人群在工作记忆，执行能力，反应时和内隐记忆方面能力降低。脑结构和功能的改变是这些认知能力下降的神经基础。长期慢性高原暴露人群仅在视觉构建能力方面轻微减弱。 本研究提示，高原环境适应伴随着局部脑结构和功能的改变。其中，岛叶的结构改变可能参与高原呼吸的适应调节。这种脑的适应性变化以认知能力的损害作为代价。长期慢性中度高原暴露仅轻微影响认知能力。</p