摘要：瘤胃是反刍动物特有的消化器官,其错综复杂的微生物区系在整个消化过程中扮演核心角色,通过一系列厌氧代谢途径对饲料中的有机物质进行降解,同时生成甲烷(CH_(4))。作为一种强效温室气体,CH_(4)的产生不仅导致能量的损失,还会加剧全球气候变暖。因此,寻找更多更有效的措施来抑制瘤胃CH_(4)排放对于提高动物生产性能及缓解气候变化具有重要意义。瘤胃微生物和饲粮营养是影响反刍动物CH_(4)排放的两大因素。文章阐述了产甲烷菌、细菌、原生动物和厌氧真菌在瘤胃CH_(4)生成过程中发挥的作用,归纳总结了调整饲粮组成、添加化学抑制剂、植物性饲料添加剂和直接饲喂微生物等方法在降低CH_(4)排放方面的作用效果,为反刍动物CH_(4)减排策略的实施与应用提供参考。

摘要：亚麻作为园林景观植物在园林造景方面有很大的应用潜力,进行亚麻表型多样性分析并确定适宜进行园林造景的亚麻材料,能够为亚麻花卉的合理配植提供参考,为其在园林造景的科学合理性提供数据支撑。以新培育的200个亚麻品系为试验材料,测定其观赏性状指标,调查和统计花瓣色、花柱色、花药色、花丝色、株高、工艺长、分枝、蒴果等相关指标,进行表型多样性分析,同时结合园林造景特点,分析亚麻花卉在景观应用中的配置设计,探究亚麻作为园林景观植物的观赏潜力。结果表明,200份亚麻品系的8个观赏表型性状间的变异性较大;亚麻花色在主成分分析中贡献率最高,其中花瓣色和蒴果特征值较大;R型聚类分析将亚麻的8个性状聚为3类,观花性状聚为一类,观株性状聚为一类,观果性状聚为一类;Q型聚类分析将200份亚麻材料聚为6类,第Ⅰ类群(176个亚麻品系)、第Ⅱ类群(KJ054、KJ117、KJ118、KJ127、KJ138、KJ153、KJ154、KJ191、KJ192、KJ197)、第Ⅲ类群(KJ002、KJ006、KJ007、KJ010、KJ014、KJ016)和第Ⅴ类群(KJ094、KJ115、KJ189、KJ193、KJ199、KJ200)的亚麻材料表型性状表现优异,适合作观花或观株花卉。综上所述,200份亚麻材料具有丰富的表型多样性,在园林中有良好的应用前景,亚麻可作为一种观赏性与实用性相结合的新型园林花卉。

摘要：In the process of unprecedented urbanization in contemporary China, a great many of Chinese cities have witnessed a rapid expansion of urban scale to different degrees. With the continuous compilation, amendment and enforcement of urban planning, the functional structure, spatial environment, street patterns and textures and even the social aspect of cities have changed conspicuously, all of which have directly happened to the spatial forms of the dimension, or even the multi-dimension of a certain city. By describing and analyzing the structure, evolution and explicit tokens of the spatial forms of cities, this thesis attempts to set up a model of factors that affect urban forms, as well as discuss the attributes, protection, adjustment and development-potential of urban land closely associated with forms. In addition, on the basis of the professional features for urban design to participate in the modeling and construction-management of desirable spatial forms of cities, the author has put forward technical measures for quantitatively appraising and analyzing the large-scaled spatial forms of cities, thus offering technical support to municipal governments and management departments of planned construction.

摘要：A model for conceptual design of mechanical devices is studied based onqualitative simulation. In this model, the desired functions are expressed bystate-transit-diagrams(ST-diagrams) and design space is represented byqualitative-state-curves(QS-curves). The first design idea, called seeds idea, is proposed by thedesigner and then is abstracted into QS-curves. The qualitative simulation is implemented based onthe QS-curves. By changing the motion of acting parts, the connection of parts and the motion ofdriving part, new design ideas are generated. With this model, a series of new design ideas derivedfrom the seeds idea can be achieved.

摘要：Four optimal approaches of high-order finite-impulse response(FIR) digital filters were developed for designing four types filters using neural network algorithms. The solutions were presented as parallel algorithms to approximate the desired frequency response specification. Therefore, these methods avoid matrix inversion, and make a fast calculation of the filter’s coefficients possible. The convergence theorems of these proposed algorithms were presented and proved to illustrate them stable, and the implementation of these methods was described together with some design guidelines. The simulation results show that the ripples of the designed FIR filters are significantly little in the pass-band and stop-band, and the proposed algorithms are of fast convergence.

摘要：全景式情境是核心素养导向课程改革等的应然期待,旨在解决当前教学情境创设存在的情境设计主体错位、过于关注知识功用、结构化无度、情境拼接问题。教师进行全景式情境创设,不仅要紧扣核心大概念,匠心独运精选情境,还要结构化设计情境,科学理性巧构情境,做到巧设入胜之境、彰显有我之境、构建全景之境。

摘要：为了提高定向井硬质地层中的机械钻速,设计了一种短长度全金属的复合脉冲钻井提速工具。该工具能同时产生高频低幅的扭转冲击和轴向脉动冲击,且两种冲击为串联结构。基于所设计的工具特点及工作原理,利用理论分析与数值模拟相结合的方式,分析了扭转冲击压降及水力脉冲结构内部流场域,并对工具样机进行了性能试验。研究表明,该工具中扭转冲击喷嘴尺寸越小,扭转冲击压降越大,近似成二次函数关系;试验中,摆锤两端面会产生压差波动,两端面的压力呈正压差、负压差交替波动趋势,表明扭转冲击能够及时完成换向,推动摆锤往复运动;该工具中水力脉冲能产生轴向脉动冲击,且压降随流量增加而增大,近似呈二次函数关系,同时明确了轴向水力脉冲产生轴向冲击的原理。该工具的研制为定向井的提速提效提供了一种新手段。

摘要：以11个理化指标为品质指标,采用权重法构建综合得分模型,再以超声波的温度、时间和功率为因素,通过正交设计优化适用于火锅刷煮的速冻牦牛酸醡肉片的腌制工艺。同时,以未腌制和传统工艺腌制的牦牛酸榨肉片为对照,结合电子鼻、电子舌与GC-IMS技术,分析其速冻前后风味特征的变化。结果表明:超声波辅助腌制的最佳条件为超声温度30℃、超声时间25 min、超声功率400 W。经超声波辅助腌制的牦牛酸醡肉片,速冻前后色泽、质构、气味和滋味的差异不大,超声冷冻后风味物质种类和浓度均有所增加,说明超声辅助腌制能带来较好的风味特征。

摘要：本文重点开展PCCP受载响应分析中三种预应力模拟施加方法的比较研究。将等效荷载法、等效降温法和缠丝模型这三种PCCP的预应力模拟施加方法应用于南水北调中线4m内径的埋置式PCCP,模拟施加其预应力场,并对其进行受载响应的数值模拟分析,还对该PCCP进行了原型压力试验,并将试验结果与计算结果进行综合对比分析。结果表明,计算结果与试验吻合较好,均能反映PCCP的受载响应规律;但等效荷载法不能考虑钢丝的刚度贡献和承载作用,给出的PCCP的起裂荷载和爆管荷载偏低;等效降温法不能反映钢丝的实际应力应变状态;缠丝模型不仅能考虑钢丝刚度贡献和承载作用,反映钢丝的实际应力应变状态,还能描述钢丝与其余部件的相互作用,具有更好的适用性。说明今后更适合以缠丝模型作为PCCP数值模拟分析的基础,进一步对PCCP的断丝响应以及结构安全性进行深入研究。

摘要：The paper presents a dynamic model intervened by urban design for the decision-making of land development intensity, which expresses the inherent interaction mechanism between lands based on the evaluation of land attributes and their similarity relationship. Each land unit is described with several factors according to their condition and potential for development, such as land function, accessibility, historical site control, landscape control, and so on. Then, the dynamic reference relationship between land units is established according to the similarity relationship between their factors. That means lands with similar conditions tend to have similar development intensities, which expresses the rule of the spontaneous urban development. Therefore, the development intensities of the pending lands can be calculated by the confirmed ones. Furthermore, the system can be actively intervened by adjusting the parameters according to urban design or planning intentions. And the reaction of the system offers effective support and reference for reasonable decision. The system with multiple intervention input is not only a credible tool for deriving development intensities, but also a platform to activate urban design conception. Above all, the system as a socio-technical tool integrates the optimization of form, function and environment, and embodies the principle of impersonality, justice and flexibility in the decision of land development intensity.