Breeding of high malate‐producing diploid sake yeast with a homozygous mutation in the VID24 gene

Malate is an important taste component of sake (a Japanese alcoholic beverage) that is produced by the yeast Saccharomyces cerevisiae during alcoholic fermentation. A variety of methods for generating high malate‐producing yeast strains have been developed to date. We recently reported that a high malate‐producing strain was isolated as a mutant sensitive to dimethyl succinate (DMS), and that a mutation in the vacuolar import and degradation protein (VID) 24 gene was responsible for high malate productivity and DMS sensitivity. In this work, the relationships between heterozygous and homozygous mutants of VID24 and malate productivity in diploid sake yeast were examined and a method was developed for breeding a higher malate‐producing strain. First a diploid yeast was generated with a homozygous VID24 mutation by genetic engineering. The homozygous integrants produced more malate during sake brewing and grew more slowly in DMS medium than wild‐type and heterozygous integrants. Thus, the genotype of the VID24 mutation influenced the level of malate production and sensitivity to DMS in diploid yeast. Then a homozygous mutant from a heterozygous mutant was obtained without genetic engineering by ultraviolet irradiation and culturing in DMS with nystatin enrichment. The non‐genetically modified sake yeast with a homozygous VID24 mutation exhibited a higher level of malate productivity than the parent heterozygous mutant strain. These findings provide a basis for controlling malate production in yeast, and thereby regulating malate levels in sake. Copyright © 2016 The Institute of Brewing & Distilling     

T700/6421复合材料层板低速冲击后损伤特性

对未增韧及增韧后的T700/6421复合材料层板进行了低速冲击实验,讨论了表面凹坑深度(D)、表面凹坑直径(R)、冲击后压缩强度(CAI)及冲击能量(E)的关系,并通过记录冲击过程中的接触力与时间的变化分析了冲击时的损伤过程。实验结果表明,增韧后的复合材料其更容易出现深凹坑及更大的表面凹坑直径,更容易实现目视明显可见损伤(VID)的效果,并通过分析冲击历程响应发现:低速冲击过程中复合材料层板起始产生分层损伤时的时间与冲击能量并没有必然的联系。     

基于VMD和LSTM模型的航空液压管路卡箍故障诊断

航空发动机液压管路-卡箍系统中卡箍振动信号具有非线性和非平稳性的特点,难以从卡箍故障信号中准确识别出其故障类型。针对该问题,提出了一种基于变分模态分解(Variational Mode Decomposition,VMD)-长短时记忆(Long Short-Term Memory,LSTM)神经网络模型的智能故障诊断方法。首先,利用遗传算法对VMD的模态分量k值和惩罚因子α进行参数优化;然后,将优化后的VMD对卡箍故障振动信号进行分解处理;最后,将分解后的模态分量输入LSTM网络中进行特征学习,从而实现卡箍故障的识别。实验表明:该方法实现了对卡箍螺栓松动状态、根部断裂状态、衬垫磨损等3种典型故障的精准识别,故障总体识别准确率能够达到98.5%以上,有效地提高了航空液压管路卡箍故障识别的准确率。     

基于视频图像分析的火燃检测及其应用

综合分析了目前视频火焰检测技术中几个主要方面,包括可视探测技术的优势,火燃事件的特性分类和视觉特征的描述,具有代表性的检测算法,典型的系统解决方案及其发展趋势等,同时也探讨了其中涉及的若干关键问题,并展望了相关研究的应用前景.     

提升预测框定位稳定性的视频目标检测

目的 目前视频目标检测（object detection from video）领域大量研究集中在提升预测框定位准确性,对于定位稳定性提升的研究则较少。然而,预测框定位稳定性对多目标跟踪、车辆行驶控制等算法具有重要影响,为提高预测框定位稳定性,本文提出了一种扩张性非极大值抑制（expanded non-maximum suppression,Exp_NMS）方法和帧间平滑策略（frame bounding box smooth,FBBS）。方法 目标检测阶段使用YOLO（you only look once）v3神经网络,非极大值抑制阶段通过融合多个预测框信息得出结果,增强预测框在连续视频流中的稳定性。后续利用视频相邻帧信息关联的特点,对预测框进行平滑处理,进一步提高预测框定位稳定性。结果 选用UA-DETRAC（University at Albany detection and tracking benchmark dataset）数据集进行分析实验,使用卡尔曼滤波多目标跟踪算法进行辅助验证。本文在MOT（multiple object tracking）评价指标基础上,设计了平均轨迹曲折度（average track-tortuosity,AT）来直观、量化地衡量预测框定位稳定性及跟踪轨迹的平滑度。实验结果表明,本文方法几乎不影响预测框定位准确性,且对定位稳定性有大幅改善,相应跟踪质量得到显著提升。测试视频的MOTA（multiple object tracking accuracy）提升6.0%、IDs（identity switches）减少16.8%,跟踪FP（false positives）类型错误下降45.83%,AT下降36.57%,mAP（mean average precision）仅下降0.07%。结论 从非极大值抑制和前后帧信息关联两个角度设计相关策略,经实验验证,本文方法在基本不影响预测框定位准确性的前提下,可有效提升预测框定位稳定性。     

Identification of a novel gene controlling homothallism in the yeast Kazachstania naganishii isolated in Japan

A novel gene controlling homothallic life cycle was identified in the yeast Kazachstania naganishii isolated in Japan. This gene was isolated by means of complementing a mutation, mti1, which had led to heterothallism from original homothallism in the yeast. The configuration of original mutation in MTI1 gene revealed that a truncated product is formed due to occurrence of a stop codon by a nucleotide insertion. When the gene was disrupted with a marker, the disruptant spore clone was haploid and stably heterothallic. Disfunction of the gene caused inability to self‐diploidize due to defect of mating‐type interconversion. The gene MTI1 (for Mating Type Interconversion) is a weak homolog of the Saccharomyces cerevisiae VID22/ENV11, which has been reported to function in vacuolar protein processing. K. naganishii has a gene representing significant homology with the HO gene of S. cerevisiae on chromosome V, which has not been clarified to be involved in regulation of life cycle in K. naganishii. The MTI1 gene defined in this study is located on K. naganishii chromosome IV and does not represent significant homology to the above ScHO‐like gene and any other genes concerning life cycles of yeasts. From the viewpoint of gene evolution, it is extremely interesting that the MTI1 gene is a new type of gene controlling homothallism in addition to an HO‐type gene, leading to discovery of an unknown mechanism regulating life cycles in yeasts.     

计算机微处理器VRD11电源方案的研究与开发

本文以INTEL VRD11处理器核电源规范为基础，提出一项支持INTEL新核心处理器的计算机主板处理器电源设计方案．并构建一个符合新一代处理器供电规范的模型，结合实际电路研究其实现方法．     

基于PMBus和VID技术的电源电路设计

针对高速嵌入式系统对自动调节输出电压的电源系统的需求,本文采用PMBus总线为电源芯片之间,电源芯片和控制器之间的通信提供标准,通过重点分析基于PMBus总线的数字可编程电源的内部结构和电压识别的技术实现方法,设计了一支持电压识别(VID)技术的带两路独立电压输出的数字可编程电源系统。经PMBus总线进行配置后,该电源系统可以满足高速嵌入式系统的多种电压需求,取得了良好的效果。     

产品开发过程中的VID技术

本文介绍了虚拟工业设计技术出现的必然性,探讨了VID在当今信息时代的作用和应用前景,并讨论了VID的关键技术,结合加油车实例介绍了VID技术的开发应用过程。