Stipe Trimming at Harvest Increases Shelf Life of Fresh Mushrooms (Agaricus bisporus)

Trimming the stipe of cultivated mushrooms, Agaricus bisporus, from 35 mm to 5 mm from the cap immediately after harvest resulted in improved shelf life as indicated by reduced browning and slower cap opening. This effect was evident after 3 days storage at 12°C, and became more pronounced after 6 days. Trimming the stipes had no significant effect on postharvest respiration rate or bacterial growth; thus, the shelf life improvement was due to other factors. Stipe trimming reduced the weight (yield) of saleable mushrooms by about 10%; thus, shelf life improvement would need to offset any economic loss to growers to make this practice commercially feasible.     

Design of a trimmed current reference with a low temperature drift

Component tolerances and mismatches due to process variations severely degrade the performance of bandgap reference circuits. Based on device mismatch models, a current reference I_ref with adjustable output current from 15μA to 80μA is designed. A compensated circuit is used to reduce the temperature drift. To achieve more accurate current reference, an 8bit bi-directional trimming array with 127 current levels is proposed. This digitally programmable array is binary weighted for accuracy and flexibility. Simulation shows that the temperature coefficient is 26ppm/℃ over the wide range of -40℃ to 120℃when the output current is 15μA. Based on the CMOS 0.13μm technology, the measurement results show that the trimmed range and precision for current reference are -14.3％·I_ref～14.3％·I_ref and 0.11％·I_ref, respectively. The circuit could be applied to high precision A/D and D/A converters.     

基于激光刻蚀技术石英晶振频率微调系统的设计

根据石英晶振频率微调机理及激光刻蚀特性,设计软件、硬件实现了一个基于PC机和激光器的石英晶振频率微调装置,并提出了一种实用刻蚀方案,可实现对多片晶片同时微调,能有效地消除微调过程中出现的温漂等问题,同时讨论了提高微调速度及合格率的方法．     

微机械振动陀螺模态耦合误差分析与激光修形方法研究

较大的模态耦合误差严重影响陀螺仪的零偏稳定性。研究了一种微机械振动陀螺仪的模态耦合误差形成机理,仿真分析了结构加工误差对模态耦合误差的影响规律。仿真结果表明:振动结构支撑梁上的加工误差是引起结构刚度不对称并产生模态耦合误差的主要因素,在与该加工误差对称的位置去除相应的材料可以减小甚至消除模态耦合误差。采用紫外激光微细加工技术,对微陀螺样机进行了结构平衡实验,激光修形后在没有输入角速度时,微陀螺样机模态耦合误差信号的峰峰值从2.88 V降低到0.24 V,取得了明显的修形效果。     

红旗轿车装饰板左右支柱注射成型过程

借用塑料模ＣＡＥ分析软件Ｃ－ＭＯＬＤ分析了红旗轿车装饰板左右支柱在成型过程中和实际装车中所遇到的问题及其原因，并提出相应的解决办法。     

三轴传动滚切式双边剪的设计特点

阐述了滚切式双边剪的高精度、高效率等优点,并着重对其自主设计的三轴三偏心滚切式双边剪的结构特点及工作原理做了详细论述     

适力压边式落料拉伸切边复合模设计

介绍了筒形类零件的落料、拉伸、切边复合模 ,该模具采用特殊压边结构使压边力随拉伸行程的增加而增大 ,当达到最大值后又逐渐减小 ,以符合拉伸变形规律 ,并且该模具在拉伸结束的同时进行切边 ,减少了工序 ,提高了生产效率     

壳体工艺分析及模具设计

对壳体的冲压工艺进行了分析,介绍了拉伸、切边模具结构设计的要点。对类似冲压零件的模具设计具有一定的参考作用。     

Short communication: Use of lameness scoring to genetically improve claw health in Austrian Fleckvieh,Brown Swiss,and Holstein cattle

The specific objective of this study was to evaluate the use of lameness scoring to genetically improve claw health in Austrian Fleckvieh, Brown Swiss, and Holstein cows based on data from the “Efficient Cow” project. In 2014, a 1-yr data collection was carried out. Data from 6,519 cows kept on 161 farms were recorded. At each time of milk recording, lameness scores were assessed by trained staff of the milk recording organizations. Hoof trimming on these farms was documented and recorded as well. Veterinarian diagnoses and culling due to foot and leg problems from these farms were available from the routine recording system. As repeated lameness records per cow and lactation were available, an overall lactation lameness score was calculated. Estimated heritabilities for lameness were 0.11, 0.05, and 0.09 for Fleckvieh, Brown Swiss, and Holstein, respectively; however, only heritability estimates for Fleckvieh were significantly different from zero. Breeding values for lameness were obtained, reversed in sign, and cows were ranked according to their breeding value. A low breeding value for lameness resistance (the bottom 10% of the cows) was associated with a significantly higher frequency of trimmed cows, which indicates that the cows selected by the farmer to be trimmed are not completely random. Additionally, a high breeding value for lameness resistance (the top 10% of the cows) was associated with lower frequencies of claw diseases recorded at trimming, claw and leg diagnoses, and culling due to foot and leg problems, which highlights the usefulness of lameness scoring for genetic improvement of claw health. Overall, selecting for a better lameness score has the potential to reduce claw diseases, especially the frequency of severe claw diseases that lead to culling.     

红军东征总指挥部旧址建筑群研究

介绍了红军东征总指挥部旧址“立体交融式”的布局特征,通过对砖木结构的东西厢房和全院青砖贴面的外部装修进行的分析,阐述了该建筑群从总体上脱离了“浓郁”的黄土文化特征,并指出建筑群的细部装饰有近代特征,且建筑群的设计思想有近代新思想与传统文化的融合。