彻底改革户籍制度,实现迁徙自由

迁徙自由是公民的基本权利，是对公民追求幸福生活，实现人生价值的确认与保障。在我国，户籍制度虽历经调整，但总体上仍然是一种身份制度，是计划经济的坚固堡垒和现代化建设的绊脚石。改革户籍制度，实现迁徙自由，是我国经济持续增长和现代化发展的迫切需要。目前提出的暂缓迁徒自由的种种观点，集中表现为对农民进城的恐惧，这是对社会发展缺乏自信力的一种表现。运用多学科的观点对户籍制度改革的重大意义和改革策略进行分析，认为对户籍制度进行改革的时机已经成熟。     

Optimizing quality of dental carving by preclinical dental students through anatomy theory reinforcement

Knowledge of dental anatomy is of great importance in the practice of dentistry, especially in oral rehabilitation, because without this knowledge, professional practice is not possible. Dental carving plays a major role in training dental students as it develops their manual dexterity. This randomized controlled trial aimed to evaluate the influence of didactic‐theoretical reinforcement on the theoretical and practical knowledge of dental anatomy of preclinical students by examining the quality of the anatomical restorations performed by these students before and after a didactic‐theoretical reinforcement. For the evaluation of theoretical knowledge, a questionnaire with closed questions about dental anatomy was used. To evaluate the effect of didactic reinforcement on dental carvings, two groups of 15 preclinical students were assessed. Experimental group (G1) received a three‐hour theoretical tutoring on dental anatomy, while the control group (G2) did not. The dental carving scores obtained by the two different groups were compared using Student's t‐test. Cohen's d was used to estimate the effect sizes between groups. The frequency of correct answers given for each theoretical knowledge question was compared in each group using Fisher's exact test. T‐test was also used to compare the means of the two groups' final scores of theoretical evaluations. To compare these final scores obtained in both carving and theoretical tests, a principal component analysis was performed with different items assessed in each test to obtain factor loading scores and a final weighted score, where factor loadings were considered for each item. Weighted scores were compared using t‐test. Also, scores obtained during the head and neck course were assessed and compared using t‐test. Spearman's correlation test was used to assess the correlation between scores obtained prior to the anatomy course and scores obtained in the dental carving exercise. The theoretical evaluation revealed no significant difference between the grades (mean ± SD) of G1 (85.1 ± 6.6%) and G2 (86.2 ± 9.1%) with the grades of a baseline test that was previously obtained when students submitted to the study (P = 0.725). Regarding the tooth carving assessment, the dental carving quality by students of G1 has significantly improved, except for tooth #23 (P = 0.096). Theoretical reinforcement of dental anatomy seems to improve the students' carving performance but does not enhance their knowledge about dental anatomy. Anat Sci Educ 11: 377–384. © 2017 American Association of Anatomists.     

影响齿轮工作平稳性的加工误差分析

生产实践和理论分析表明，影响齿轮工作平稳性的主要因素是齿轮的基节偏差△fpb和齿形误差Affa基节偏差会引起一对齿过渡到另一对齿啮合传动比的突变；齿形误差会引起每对齿啮合过程中传动比的瞬时变化。两者都是齿轮一转中多次重复出现的小周期误差，会产生振动和噪音，影响齿轮传动的平稳性。滚齿时被切齿轮的基节偏差较小，而齿形误差通常较大，该文全面分析了滚齿过程中二种误差的成因及控制方法。     

楔状缺损治疗失败的原因分析

[目的]通过远期疗效的观察,分析楔状缺损治疗失败的原因.[方法]79例518颗楔状缺损牙分别用光固化复合树脂和进口玻璃离子修复,于修复后1、2年及4年根据一定指标评价其疗效.[结果]楔状缺损修复后的临床成功率从2年时的85.3%,下降为4年时的27.6%,并发现1.7%(修复后2年)和6.6%(修复后4年)的患牙原楔状缺损修复体颈缘下方出现的新"楔状缺损".疗效受多种因素影响,有咬合因素患牙组的临床失败率明显高于无咬合因素组.[结论]楔状缺损修复治疗失败率受患牙承担咬合力的大小和修复材料物理性能的影响,提示在楔状缺损的治疗中,一定要考虑咬合因素的祛除.     

自由化与律化:20世纪新诗诗体建设历史简析

百年新诗取得了较大的成绩，由于历史原因和特殊的时代背景，如20世纪有太多的战争和运动，百年新诗一直处在诗体自由化与律化多对抗少和解的特殊生态中，经历了一条十分曲折的诗体构建之路，诗体建设总是呈现“定型难”特点，没有建设起大家公认的诗体。现代时期是最重要的诗体建设期。但是整个世纪，都只有少数诗人艰难地致力于诗体建设，现在有必要加强新诗的诗体建设。     

积和式的性质与应用

积和式的计算是组合矩阵理论中一个相当困难的问题,给出了积和式的一些基本性质,并进一步讨论了某些特殊矩阵的积和式的计算.     

法制建设是反腐败的治本之策

社会转型和体制转轨时期滋生的腐败是生长在我们国家肌体上的一颗毒瘤。干部人事制度、法制、权力监督制度等方面的缺陷是腐败现象滋生蔓延的深层次原因,对症下药地加强法制建设是反腐败的治本之策。     

表面磁钢永磁无刷电机电磁转矩的解析法分析

With the air gap magnetic field distribution of surface mounted permanent magnet (PM) motors obtained using an analytical technique, the instantaneous electromagnetic torque and its corresponding components are investigated with the Maxwell stress tensor method. Accurate results can easily be achieved using the proposed method without using the tedious finite element analysis (FEA). In this paper, the electromagnetic torque of a surface mounted PM motor with two phases energized is decomposed into four torque components. This technique is useful not only for the design and optimization of the permanent magnet motor, but also for the choice of control strategy.     

基于Ansoft的自动门用永磁无刷直流电机的设计和分析

对用于自动门控制系统的永磁无刷直流电动机,采用基于等效磁路法的RMxprt软件和基于电磁场有限元分析法的Maxwell软件对样机进行设计、分析和计算,并用＂场路结合＂的设计思路,完成了一台12槽/8极无刷直流电机的电磁设计任务。     

Effects of orthodontic load on the periodontium of autogenously transplanted teeth in beagle dogs

Objective:To observe the periodontal healing of autogenously transplanted teeth loaded orthodontically after autotransplantation in Beagle dogs.Methods:Forty-eight teeth were autogenously transplanted,24 of which were loaded postoperatively with orthodontic force at different time points and for different durations.Periodontal healing was evaluated by probing pocket depth(PPD),the expression of relevant proteins,and histomorphometric analyses.Results:The dental pockets of loaded and non-loaded teeth were both much deeper after the first postoperative week than before transplantation(P<0.05).Later,the PPD,which was measured after postoperative weeks 1,3,5,9 and 13,gradually became shallow.The expressions of alkaline phosphatase(ALP)and basic fibroblast growth factor(bFGF)were higher in loaded teeth than in non-loaded teeth(P<0.05),and in groups subjected to two weeks duration of loading than in other groups at the same load time point(P<0.05).For the same load duration,the expressions of ALP and bFGF in teeth loaded after postoperative week 4 were higher than those of other treatments(P<0.05).According to histomorphometric analyses,an orthodontic force on transplanted teeth applied after postoperative weeks 4 or 8 for two weeks duration should be favorable for periodontal healing.Conclusions:It is advisable to apply an appropriate magnitude of force on autotransplanted teeth,such as orthodontic force,at appropriate time points and for a suitable duration,to achieve the optimal clinical prognosis following autogenous tooth transplantation.These results may serve as a basis for subsequent studies in humans so as to make clinical improvements.