多相感应电机任意非正弦气隙磁密的磁动势分析与应用

多相感应电机转矩密度的提高依赖于非正弦气隙磁密行波的合理构建,由于传统的电流相位、幅值控制策略无 法给出期望的非正弦磁密行波,因此文章研究了控制多相感应电机定子相电流中基波和谐波幅值、相位、频率的大小来 构建期望的气隙磁密波形的方法、首先基于单根载流导体产生的气隙磁动势波形,推导了任意相数、不对称、包含任意 高次谐波电流波形激励的具有典型绕组结构的多相感应电机的磁动势分布表达式。根据以上磁动势分析结论,多相电 机可通过变电流相序变极。针对气隙磁密行波逼近方波波形的案例,根据所提出的磁动势分析方法分析和预测了理想 空载励磁电流的波形。将预测波形和方波供电下的励磁电流波形进行了比较,从FFT分析结果来看,仍需微调各次谐波 电压相位,从而实现各次电流相位完全一致。     

Robust Inference for Near-Unit Root Processes with Time-Varying Error Variances

The autoregressive Cauchy estimator uses the sign of the first lag as instrumental variable (IV); under independent and identically distributed (i.i.d.) errors, the resulting IV t-type statistic is known to have a standard normal limiting distribution in the unit root case. With unconditional heteroskedasticity, the ordinary least squares (OLS) t statistic is affected in the unit root case; but the paper shows that, by using some nonlinear transformation behaving asymptotically like the sign as instrument, limiting normality of the IV t-type statistic is maintained when the series to be tested has no deterministic trends. Neither estimation of the so-called variance profile nor bootstrap procedures are required to this end. The Cauchy unit root test has power in the same 1/T neighborhoods as the usual unit root tests, also for a wide range of magnitudes for the initial value. It is furthermore shown to be competitive with other, bootstrap-based, robust tests. When the series exhibit a linear trend, however, the null distribution of the Cauchy test for a unit root becomes nonstandard, reminiscent of the Dickey-Fuller distribution. In this case, inference robust to nonstationary volatility is obtained via the wild bootstrap.     

模具钢干铣削试验及参数优化研究

为了对铣削力做进一步的研究,以及预测铣削参数的改变对铣削力变化的影响,文章建立了铣削力预测模型,引 入了PSO优化算法。试验采用正交设计方法,干式铣削SKD61模具钢;KISTLER测力仪测量铣削力;HRsoft_DW数采软 件采集试验数据,并对数据进行极差分析。研究结果表明每齿进给量是铣削参数中影响铣削力最为主要的因素。研究 验证了PSO算法对铣削参数优化问题具有有效性。     

搅拌釜内双层改进型INTER-MIG桨流场实验研究

为得到双层INTER-MIG桨搅拌釜内流场特征,文章采用粒子图像测速技术(PIV)对直径为430 mm的双层改进 型INTER-MIG桨搅拌槽内流场进行了实验研究。分析了搅拌转速、相位角及轴向位置对搅拌槽内流场分布的影响。结 果表明：整个流场表现出较强轴流特性,底桨右端形成一个漩涡;转速增加引起桨叶附近湍动增强,但整体流型变化不 大;当r/R <0.48时,桨叶间轴流效果显著,有利于釜底流体向上抬升,增强整体混合效果;当r/R>0.48时,桨叶右端在 近壁面处会形成上下2股流动流体,有助于形成局部区域循环。实验结果可为工业搅拌过程提供工艺参考。     

口述史的复调价值及其实现

布罗代尔认为,理想的历史应该是多声部的。现代意义上的口述史的出现使基于文献书写的历史的单声部特征显露无遗。口述史不再是现代社会“沉默的大多数”发出的声音。以口头陈述为基础的口述史的叙事和以文献为基础的历史的书写都同样是有关历史事实的观念的反映。各具独立旋律的叙事与书写理应建立起和谐的关系而形成复调历史。这种复调历史并非杜赞奇基于话语分析方法,以解构民族国家单线叙事为目的的复线历史。口述史与历史二者之间互补互益的差异使反思性知识与批判性知识可以对过去的历史进行检讨并对历史事实进行更为深刻的理解。借鉴历史研究方法及滥觞于研究无文字民族的民族志方法是解决口述史实践中存在的诸多问题的重要路径。     

魏晋六朝“自然”论文学观的确立——论《文心雕龙》的“文道自然”观

以"自然"论文学,汉朝<淮南子>已有记载,但只言片语,语焉不详,直到魏晋鸿篇<文心雕龙>才有了真正意义上的"自然"论文学观.刘勰以"自然之道"来阐释文学创作的根本原则,从哲学本体论高度论证"文"之产生与存在的必然性、"文"与"质"的本质统一关系,并以此为核心探讨了文学创作之发生、文学风格之生成、创作自由之实现等一系列重要问题,建立了相当系统化的"文道自然"观.     

利益分割时期的安全事故与政府改进问题

政府在事故预防和处置中居于主导地位.心理学的"华生模式"和"皮亚杰模式"实现"社会学转向",可用以分析政府的责任问题.而安全事故的"强刺激"和"弱刺激"对政府改进效应是不同的.中国当前社会转型中逐步出现了城乡、单位、地方之间而主要表现为阶层之间的利益分割局面.因而政府的责任一方面不仅仅在于对某一事故的"强刺激"进行反应性改进,更应该在于包括"弱刺激"在内逐步把内化以人为本的责任伦理和信念伦理结合起来,对事故进行事前预知和防范,同时另一方面需要抑制精英阶层对整个社会利益的割据,保障社会底层的安全权益,引导底层进行安全维权,乃至抗争上层"官商秩序(结构)"的利益勾结,打破"资(方)强劳(方)弱"、"上(层)强下(层)弱"结构,从消极的"华生模式"转向积极反应的"皮亚杰模式",不断提升政府效率,保障个体生命安全和社会安全.     

"三元"说之宗宋及其诗学价值指向

"三元"说是陈衍针对今人强分唐宋诗与扬唐抑宋的诗学观所提出的诗学纠偏策略.它以三元皆盛之论,将唐宋诗并列,同时又立足于宋诗,特别以杜、韩、黄为重心,突出宋诗对唐诗的创变与突破,从而确立宋诗地位与特征,对扬唐抑宋诗学观进行纠偏.这一诗学之根本,不在纠缠于诗歌诗艺形式上的高下判别,而关注内容精神之追求.以提倡变风变雅、振兴诗教为旨归,寄寓着关注现实人生的重要的诗学思想.     

The politics of the face: the scopic regime and the (un-)masking of the political subject

Face is commonly seen as a feature exclusive to each person. It expresses subject’s feelings, thoughts and in turn represents knowledge that is otherwise deemed personal. However, face is mistakenly seen as pure expression of subject’s thoughts. This article aims to show that face is a product of governing practices of seeing and knowing. It is thus not a unique individual expression, but a mask that the socio-political order attaches to individuals as they are turned into political subjects. The article begins with a discussion of the two governing practices: the seeing (or the spectre of the visible) and the knowing (or the practice of locating faces in the socio-political field) with an aim to unveil the role face plays in the socio-political reality. The first interrogation looks at how face creates a field of recognition and opens a distinct form of political visibility: who, what and how one sees and what remains unseen. Whereas the second interrogation discusses how appearances produce meaning and how knowledge is taken off the face. Finally, the face as a knowledge producer and a mean of subject’s social recognition (identity) is put in the encounter with the idea of the anxious gaze and the work of Marlene Dumas. Instead of recognition, here a subject is met with dissociation and displacement of subject’s socio-political image. The three presented studies paint the politics of the face as an obscene governing strategy caught between endless attempts to create the face as a known, seen and governed space and illusive attempts to grasp the actual meaning of a pre-symbolised face.     

Engagement strategies and change: an intentional practice response for the child welfare worker in cases of domestic violence

In order to engage mothers who are victims of domestic abuse, the child welfare worker needs to be challenged to develop an intentional practice response that includes knowledge and skill concerning the complexities of domestic violence, as well as the process of change. Developing a supportive relationship, understanding the stages of change (SOC) and engaging mothers as leaders in the change process are essential to successful child protection outcomes. Within the context of the SOC model, this practice‐based paper focuses on the importance of engaging mothers who are victims of domestic violence in conversations about their own unique dilemmas, challenges and barriers regarding change. Through the inclusion of engagement strategies such as signs of safety, active listening and cost/benefit analysis, in concert with the SOC theory, the child welfare worker would be equipped with an approach to successfully assist mothers through their change journey, ultimately keeping children safe.