Short communication: Effects of dietary nonstructural carbohydrates pre- and postpartum on reproduction of grazing dairy cows

The working hypothesis was that postpartum anovulatory intervals (PPAI) of grazing dairy cows are shortened by inclusion of concentrates that increase the nonstructural carbohydrate content of the transition diet. Dietary treatments were arranged as a 2 × 2 factorial, with 68 multiparous cows assigned to isoenergetic diets (114 MJ of metabolizable energy/cow per day) of pasture and pasture silage (PreP) or pasture and pasture silage supplemented with 3 kg of dry matter/cow per day a corn- and barley-based concentrate for 36 d prepartum (PreC). After calving, cows within each prepartum diet group were managed on isoenergetic diets (179 MJ of metabolizable energy/cow per day) of either pasture and pasture silage (PostP) or pasture and pasture silage supplemented with 5 kg of dry matter/cow per day a corn- and barley-based concentrate (PostC) for at least 35 d and until reestablishment of ovulatory cycles. Relative to day of calving (d 0), blood samples were collected at least weekly from d −28 to 35 and milk samples were collected twice weekly for progesterone determination to diagnose ovulatory status. The main variable of interest was PPAI, defined as the interval between calving and the first detected increase in milk progesterone (>3 ng/mL), followed by a pattern of progesterone concentrations consistent with onset of an ovulatory cycle. Subsequent mating records, pregnancy testing, and recalving data were also examined. Prepartum diet did not affect reproduction. The PPAI was 8 d shorter and the 6-wk pregnancy rate was 17% greater in PostC cows compared with PostP cows. Measured indicators of metabolic state and energy balance were poorly related to PPAI. The results support the existence of nutritional signals associated with nonstructural carbohydrates in the postpartum diet, independent of energy balance; these signals benefit the physiological mechanisms underlying the timing of first ovulation and possibly subsequent breeding performance.     

重质调合油替代重油在加热炉上的应用与开发

重质调合油在加热炉上燃料使用，使轧钢的燃料成本有了一定幅度的下降，同时解决了废油的污染问题，取得了较好的经济效益和环境效益。     

纯天然功能性橘子纤维在食品品质提升,成本节约和营养强化方面的应用

橘子纤维作为纯天然功能性食品原料源白美国佛罗里达橘子原浆,目前行销世界各国并已经开始进入中国市场.独创的纯天然加工工艺赋予橘子纤维独特的功能性包括持水性,乳化性,脂肪替代,黏度控制等.其强大的功能性和纯天然绿色食品的本质使其在各个食品行业尤其是烘培业,肉制品,乳产品,方便食品,酱料和饮料方面得到广泛的应用.本文旨在用科学的数据从生产科技,产品组分和具体应用来阐明橘子纤维的特点和优势,从而帮助广大中国食品生产商了解产品如何帮助提升产品品质,节约成本和强化营养.     

金沙江梯级水库群供水发电联合调度研究

为使金沙江下游梯级水库群在不同典型年、不同调度期下的实际调度中发挥最大效益,以梯级总发电量最大和缺水量平方和最小为目标,建立金沙江下游水库群优化调度模型,采用NSGA-II算法对其进行求解,得到不同典型年和分周期下的非劣解集,并引入置换率的概念分析两目标间的竞争关系,最后分析了枯水年不同偏好下的水位过程。结果表明：发电与供水目标间的竞争关系主要体现在水库蓄水期与供水期,在汛期与汛前消落期为协同关系;供水-发电目标置换率随梯级发电量呈递增趋势,依据置换率曲线得到不同梯级发电量情况下提高单位发电量对供水造成的影响,在实际调度中设置合理发电量可以使得发电、供水目标效益最大化。     

本体ABS用橡胶国产化替代分析及评价

以3种本体丙烯腈?丁二烯?苯乙烯聚合物（ABS）牌号树脂胶液配比和工艺参数为基准,从橡胶的种类、结构、活性官能团数量、黏度、分子量及其分布等方面进行参照对比,选用1种适合本体ABS合成用国产橡胶,代替专利商指定配方用胶（720AX和565T橡胶）,在4釜串联平推流本体ABS小试装置上进行试验。通过对原橡胶与替代橡胶在结构、性能上的差异对比,结合相应ABS树脂的试样性能表征分析,对选用替代橡胶的可行性做出分析和评价。结果表明,国产编号BR?A胶与720AX胶在试验过程中表现的性能差异性较小,可相互替代;国产编号BR?B胶中的1,2?乙烯基含量偏低,橡胶分子量偏大,若替代565T胶,还需进一步进行性能优化。     

Influence of heat treatment temperature on the properties of the lithium disilicate-fluorcanasite glass-ceramics

This study aims to investigate the influence of heat treatment temperatures on the mechanical properties and chemical solubility (CS) of lithium disilicate-fluorcanasite glass-ceramics and to develop new dental materials. The glasses and glass-ceramics were prepared using CaF₂-SiO₂-CaO-K₂O-Na₂O-Li₂O-Al₂O₃-P₂O₅-based glass system using a conventional melt quenching method followed by a two-stage crystallization process. This two-stage method involves two heating temperature steps: first at a constant temperature (T_S1) of 600°C and second step at varying temperatures (T_S2) of 650, 700, 750, and 800°C. The crystallization behavior, phase formation, microstructure, translucency characteristic, density, hardness, fracture strength, and CS were investigated. It was found that the lithium disilicate crystal acted as the main crystalline phase, and the crystalline phase of fluorcanasite occurred at the heat treatment temperatures of 750 and 800°C. In addition, it was found that density, hardness, fracture strength, and CS increased while the translucency values decreased with increasing heat treatment temperatures. Furthermore, the CS increased dramatically when the fluorcanasite phases occurred in the glass-ceramic samples. The maximum density values, Vickers hardness, fracture toughness, and flexural strength are 2.56 g/cm³, 6.73 GPa, 3.38 MPa.m^1/2, and 259 MPa, respectively. These results may offer a possibility to design a new material for dental applications based on lithium disilicate-fluorcanasite glass-ceramics.     

Caching strategy based on node’s importance to community in information-centric networks

In-network caching is one of the most important features of ICN (information-centric networks).A caching strategy based on node’s importance to community was proposed to make content objects cached more reasonable in temporal and spatial distribution.Within each community,the strategy not only caches content objects in those nodes where users are easy to access the content,but also makes different popularity of content objects more reasonable in temporal distribution.The CSNIC strategy was implemented under a variety of experimental conditions,and compare it with the previous strategies CEE-LRU,Betw-LFU and Opportunistic.The simulation results show that the strategy can yield a significant performance improvement,such as,cache hit ratio,hop reduction ratio,content diversity ratio and number of replacement.Furthermore,the additional overhead of CSNIC is small.     

Design,simulation and testing of an isotropic compliant mechanism

In this paper, the concept of isotropic compliance is extended to the field of compliant mechanisms. Starting from the design of a rigid-body mechanism, a planar compliant system is determined by applying the rigid-body replacement method. The static behaviour of the isotropic compliant mechanism is validated by finite element simulations and experimental tests. The extension of the proposed method to the Euclidean Space E(3) is discussed.     

Empirical Circuit Breaker Failure Rate Assessment and Modeling in a Preventive Maintenance Application

This article presents an analysis of the failure rates of SF6 puffer circuit breakers in the 230-kV voltage class. Historical failure recorded data for existing power circuit breakers in high-voltage substations in Thailand from 1992 to 2011 were retrieved. Subsequently, the data were analyzed and classified based on the causes of failure related to circuit breaker sub-components. The failure rates of the individual circuit breaker sub-components were determined. These failure rates were then categorized into three main circuit breaker component categories based on their functionality, which includes the live part and insulation, operating mechanism, and control part. The failure rates of the individual circuit breaker sub-components were calculated, and their associated probability distributions were estimated using Weibull distribution functions. The resulting Weibull distribution parameters were subsequently utilized in a circuit breaker preventive maintenance application to aid in the decision-making process for setting the maintenance schedule of the circuit breaker components. Finally, circuit breaker reliability is also monitored. This proposed method can also be applied to other high-voltage equipment in power systems.     

计算架空线路分布参数的新方法

提出一种考虑土壤电阻率影响的架空输电线路分布参数计算新方法。介绍和分析了Carson公式和Dubanton公式,提出用函数代替的方法简化Carson校正项来避免Carson公式计算困难、Dubanton公式误差较大的问题,总结出一种计算精度较高的架空线路分布参数计算新方法。误差分析表明,该方法的计算公式简单、计算值连续、计算结果较精确。该方法可替代Dubanton公式进行相应的计算和分析,在电力系统分析、仿真及计算中具有很强的实用价值。