基于 PFC -PID 的锅炉汽包水位控制系统

根据预测函数控制（Predictive Functional Control,PFC）的基本原理和应用特点,在分析其一般算法的基础上,设计了余热锅炉汽包水位控制系统的预测函数控制器。通过内回路采用传统 PID,外回路采用预测函数控制———预测函数控制与PID 串级控制相结合,取代传统的汽包水位三冲量串级 PID 控制。MATLAB 仿真结果表明,与传统 PID 控制策略相比,PFC PID 控制策略能快速消除给水流量的扰动,且具有较强的鲁棒性,动态品质良好。     

英汉词义宽窄对比

英汉两种语言中的相应词汇所涵盖的语义范围往往各不相同，到底是“英宽汉窄”还是“汉宽英窄”，从宏观角度来下判断往往不能导出科学的结论，但若从微观角度、从不同的层面分析，可发现英汉词义各有宽窄。从英汉上义词、下义词、同义词及多义词的角度入手探讨对比，可找到英汉词义宽窄的某些规律；而从词汇学、词源学、语义学及社会文化因素等方面也可找到其相应的理据。     

The concepts of 'sameness' and 'difference' in an insect

Insects process and learn information flexibly to adapt to their environment. The honeybee Apis mellifera constitutes a traditional model for studying learning and memory at behavioural, cellular and molecular levels. Earlier studies focused on elementary associative and non-associative forms of learning determined by either olfactory conditioning of the proboscis extension reflex or the learning of visual stimuli in an operant context. However, research has indicated that bees are capable of cognitive performances that were thought to occur only in some vertebrate species. For example, honeybees can interpolate visual information, exhibit associative recall, categorize visual information and learn contextual information. Here we show that honeybees can form 'sameness' and 'difference' concepts. They learn to solve 'delayed matching-to-sample' tasks, in which they are required to respond to a matching stimulus, and 'delayed non-matching-to-sample' tasks, in which they are required to respond to a different stimulus; they can also transfer the learned rules to new stimuli of the same or a different sensory modality. Thus, not only can bees learn specific objects and their physical parameters, but they can also master abstract inter-relationships, such as sameness and difference.     

Macaque monkeys categorize images by their ordinal number

The recall of a list of items in a serial order is a basic cognitive skill. However, it is unknown whether a list of arbitrary items is remembered by associations between sequential items or by associations between each item and its ordinal position. Here, to study the nonverbal strategies used for such memory tasks, we trained three macaque monkeys on a delayed sequence recall task. Thirty abstract images, divided into ten triplets, were presented repeatedly in fixed temporal order. On each trial the monkeys viewed three sequentially presented sample stimuli, followed by a test stimulus consisting of the same three images and a distractor image (chosen randomly from the remaining 27). The task was to touch the three images in their original order without touching the distractor. The most common error was touching the distractor when it had the same ordinal number (in its own triplet) as the correct image. Thus, the monkeys' natural tendency was to categorize images by their ordinal number. Additional, secondary strategies were used eventually to avoid the distractor images. These included memory of the sample images (working memory) and associations between sequence triplet members. Thus, monkeys use multiple mnemonic strategies according to their innate tendencies and the requirements of the task.     

Neuronal basis of age-related working memory decline

Many of the cognitive deficits of normal ageing (forgetfulness, distractibility, inflexibility and impaired executive functions) involve prefrontal cortex (PFC) dysfunction. The PFC guides behaviour and thought using working memory, which are essential functions in the information age. Many PFC neurons hold information in working memory through excitatory networks that can maintain persistent neuronal firing in the absence of external stimulation. This fragile process is highly dependent on the neurochemical environment. For example, elevated cyclic-AMP signalling reduces persistent firing by opening HCN and KCNQ potassium channels. It is not known if molecular changes associated with normal ageing alter the physiological properties of PFC neurons during working memory, as there have been no in vivo recordings, to our knowledge, from PFC neurons of aged monkeys. Here we characterize the first recordings of this kind, revealing a marked loss of PFC persistent firing with advancing age that can be rescued by restoring an optimal neurochemical environment. Recordings showed an age-related decline in the firing rate of DELAY neurons, whereas the firing of CUE neurons remained unchanged with age. The memory-related firing of aged DELAY neurons was partially restored to more youthful levels by inhibiting cAMP signalling, or by blocking HCN or KCNQ channels. These findings reveal the cellular basis of age-related cognitive decline in dorsolateral PFC, and demonstrate that physiological integrity can be rescued by addressing the molecular needs of PFC circuits.     

高空风力发电机组预测函数控制研究

风筝发电机组是一种新型风力发电技术.采用yo-yo结构对风筝的动态进行建模,通过作用在两风筝线上的拉力控制风筝的飞行.风筝的一个发电周期可分为发电状态和电动状态,要求在发电阶段发电量最大、在电动阶段耗电量最小,每一个阶段的控制器设计均可归结为一个约束优化问题.为解决非线性实时优化的困难,采用预测函数控制原理设计风筝发电机组的最大发电控制器,具体分析了风筝发电机组一个发电周期各阶段的控制目标,给出了闭环控制系统的实现方案.仿真结果验证了控制策略的正确性和有效性,可以满足对控制算法速度的要求.     

Neural organization for the long-term memory of paired associates

Most of our long-term memories of episodes or objects are organized so that we can retrieve them by association. Clinical neuropsychologists assess human memory by the paired-associate learning test, in which a series of paired words or figures is presented and the subject is then asked to retrieve the other pair member associated with each cue. Patients with lesions of the temporal lobe show marked impairment in this test. In our study, we trained monkeys in a pair-association task using a set of computer-generated paired patterns. We found two types of task-related neurons in the anterior temporal cortex. One type selectively responded to both pictures of the paired associates. The other type, which had the strongest response to one picture during the cue presentation, exhibited increasing activity during the delay period when the associate of that picture was used as a cue. These results provide new evidence that single neurons acquire selectivity for visual patterns through associative learning. They also indicate neural mechanisms for storage and retrieval in the long-term memory of paired associates.     

Invariant visual representation by single neurons in the human brain

It takes a fraction of a second to recognize a person or an object even when seen under strikingly different conditions. How such a robust, high-level representation is achieved by neurons in the human brain is still unclear. In monkeys, neurons in the upper stages of the ventral visual pathway respond to complex images such as faces and objects and show some degree of invariance to metric properties such as the stimulus size, position and viewing angle. We have previously shown that neurons in the human medial temporal lobe (MTL) fire selectively to images of faces, animals, objects or scenes. Here we report on a remarkable subset of MTL neurons that are selectively activated by strikingly different pictures of given individuals, landmarks or objects and in some cases even by letter strings with their names. These results suggest an invariant, sparse and explicit code, which might be important in the transformation of complex visual percepts into long-term and more abstract memories.     

文化遗产价值论析

文化遗产,包括物质文化遗产和非物质文化遗产,其价值诚如人们所确认的那样,主要体现在历史的、艺术的（审美的）和科技的三大方面。不过,这三大方面的价值并非笼统而抽象的,而是明晰而具体的,在不同文化遗产对象上有着侧重不同或程度不同的体现。另外,文化遗产的价值也不限于这三大方面,而是体现在许多方面,特别是其思想的、经济的价值不可忽略。只有全面深刻地认识到文化遗产价值的多元性和具体性,才能针对具体文化遗产做出恰切的价值评估,从而对之进行适当、有效的保护和充分、合理的利用。     

Picture encoding and retrieval： An event-related potentials study

A study-test paradigm was used to investigate the Dm (Differential memory) effect and the old/new effect of pictures. The participants were asked to judge whether the pictures were previously studied or not when they were presented with a series of pictures during the test phase. The event-related potentials (ERPs) were recorded during encoding and retrieval phases. The results showed that (1)during 400-700 ms of encoding, the remembered old pictures elicited more positive waveforms than the forgotten old pictures at frontal and central areas; (2) during 500-600 ms of retrieval, the correctly judged old pictures elicited more positive waveforms than the correctly judged new pictures at medial-midline in both hemispheres; (3) the duration of Dm effect was longer than that of old/new effect for picture. The present results suggest that the Dm effect of pictures is different from that of words and faces in spatial and temporal distributions. The neural mechanisms of picture encoding and picture retrieval are also different, which indicates that retrieval is not the simple recovery of encoding.     

新中国文艺政策产生的理论背景和文化背景

文艺政策是执政党、国家或政府对于文化艺术领域进行管理所采取的一整套制度性规定、规范、原则和要求的总称。建国以来,我们党根据不同历史时期社会发展、文艺建设的具体情况和要求,相应地制定、调整了党和国家的文艺政策,为社会主义文化领导权的建立和巩固提供了有效保障,也有力地促进了社会主义文艺事业的繁荣和发展。而马克思主义文艺观则是新中国文艺政策产生的理论背景,传统文化则是其产生的文化背景。     

基于视频和三维技术的微机原理及应用的CAI课件设计与开发

在高校教学中,CAI课件辅助教学基本普及,主要解决课程内容比较抽象、难以理解、教师用语言不易描述、某些规律难以捕捉、需要学习者反复练习的内容等,但是目前大部分的CAI课件功能比较单一,只停留在PPT里面的文字描述,简单的动画和简单的链接功能.本文分析了目前CAI课件的一些特点,介绍使用PowerPoint软件作为课件主要开发平台,综合运用Photoshop、Video Studio、3DS MAX等软件,利用软件的新技术制作基于视频和三维技术的微机原理与应用的CAI课件,提出总体思路与设计方案,并介绍制作课件的一些具体实现方法和技术技巧.     

Reducing Inconsistent Rules Based on Irregular Decision Table

In this paper, we study the problem of rule extraction from data sets using the rough set method. For inconsistent rules due to improper selection of split-points during discretization, and/or to lack of information, we propose two methods to remove their inconsistency based on irregular decision tables. By using these methods, inconsistent rules are eliminated as far as possible, without affecting the remaining consistent rules. Experimental test indicates that use of the new method leads to an improvement in the mean accuracy of the extracted rules.     

分子佐剂PHA增强小鼠特异性体液免疫的效应

目的:探讨PHA对小鼠特异性体液免疫的作用和应用价值.方法:经SRBC腹腔免疫昆明种小鼠30只,并随机等量分两组,实验组每只腹腔注射PHA 0.1ug/g,对照组注入等量N.S.5d后,两组均眼球取血,并颈椎离断处死取脾脏制备脾细胞悬液.用体外抗体形成细胞实验.(Plaque forming cell,PFC)和定量溶血分光光度测定法(Quantitativehemolysisspectrophotomentry,QHS),分别测取两组的抗体形成细胞率和QHS(495nm)OD值,经X±SD组间比较的t检验,观察有无差异性.结果:实验组的PFC形成率和QHS的OD值均显著高于对照组(p<0.01).结论:PHA有增强小鼠PFC的形成率和特异性抗体的表达.提示:PHA为分子佐剂在提高体液免疫应答的应用有较高参考价值.     

Induction of protective immunity against experimental infection with malaria using synthetic peptides

Synthetic peptides are potential vaccine candidates because they may be able to induce high antibody titres and specific cellular immune responses against native proteins and thus the whole invading organism. In a previous study we showed that immunization with molecules of relative molecular mass (Mr) 155,000 (155K) 83K, 55K and 35K, specific for the late schizont and merozoite stages of Plasmodium falciparum, could elicit either partial or total protection in Aotus trivirgatus monkeys experimentally infected with P. falciparum. Here we have chemically synthesized 18 peptides corresponding to different fragments of these proteins to immunize Aotus trivirgatus monkeys. Some peptides gave partial protection from challenge with P. falciparum parasites, but none provided complete protection individually. A combination of three partially protective peptides gave complete or almost complete protection, however, suggesting that this particular combination of peptides is a good candidate for a malaria vaccine.     

基于微观结构量化的SBS改性沥青分析

针对SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)改性沥青显微结构的量化研究方法,以SBS改性沥青偏光400倍显微结构图为研究对象,在已有量化分析方法的基础上,提出一种定量评价SBS改性沥青微观结构新方法.结果表明:新方法操作相对简单,可从微观角度量化分析不同改性剂对SBS改性沥青性能的影响,结论与试验结果一致.     

The Modeling Strategies for Open SOftware Architecture of Robot Controller

Although the modeling technologies for open robot controllers have been discussed widely,not much literature is devoted to the actual general modeling principles and strategies.The reason is that many researches focus on specific application fields.This paper accommodates for this lacuna and provides some general modeling principles and strategies.At last,the actual new modeling method-Hierarchical Object-Oriented Petri net (HOONet)which has been proved to be an effective modeling methodology,is used to illustrate the modeling strategies.     

多媒体在物理化学教学中的应用

多媒体手段具有其它教学方法不可比拟的优势 ,将其运用于物理化学教学中 ,使多媒体的图、文、声、屏与教学活动有机融合 ,就能使抽象难学的物理化学内容形象生动 ,易于被学生接受 仅对多媒体在物理化学教学中的应用进行了讨论     

新型单级功率因数校正AC/DC变换器

提出一种新型带抽头电感的单级功率因数校正AC／DC变换器。该变换器与采用两个电感的单级功率因数校正变换器同样可实现电流连续导通模式(CCM),若合理利用抽头电感的漏感有进一步减少器件的可能。对所设计的电路进行工作原理分析,并对电路进行了仿真和实验研究。实验结果证明,输入电压在宽范围内(100～240V),均满足高次谐波IEC61000—3-2 Class D国际标准,最高效率可达到87％。     

The primate amygdala represents the positive and negative value of visual stimuli during learning

Visual stimuli can acquire positive or negative value through their association with rewards and punishments, a process called reinforcement learning. Although we now know a great deal about how the brain analyses visual information, we know little about how visual representations become linked with values. To study this process, we turned to the amygdala, a brain structure implicated in reinforcement learning. We recorded the activity of individual amygdala neurons in monkeys while abstract images acquired either positive or negative value through conditioning. After monkeys had learned the initial associations, we reversed image value assignments. We examined neural responses in relation to these reversals in order to estimate the relative contribution to neural activity of the sensory properties of images and their conditioned values. Here we show that changes in the values of images modulate neural activity, and that this modulation occurs rapidly enough to account for, and correlates with, monkeys' learning. Furthermore, distinct populations of neurons encode the positive and negative values of visual stimuli. Behavioural and physiological responses to visual stimuli may therefore be based in part on the plastic representation of value provided by the amygdala.