Novel storage technologies for raw and clarified syrup biomass feedstocks from sweet sorghum (Sorghum bicolor L. Moench)

Attention is currently focused on developing sustainable supply chains of sugar biomass feedstocks for new, flexible biorefineries. Fundamental processing needs identified by industry for the large-scale manufacture of biofuels and bioproducts from sweet sorghum (Sorghum bicolor L. Moench) include stabilization and concentration of juice into syrup for long-term storage, year-round supply, efficient transport, and acceptable end-product yields. Pilot plant studies were conducted to evaluate the storage (up to 160 days at ∼25 °C) of raw and clarified syrups from sweet sorghum hybrid and commercial cultivars. Clarified syrups were manufactured after clarification of juice (80 °C; 5 ppm polyanionic flocculant) at various target limed pHs (6.1–6.8) followed by vacuum evaporation. All 70 Brix raw syrups were susceptible to microbial deterioration on the surface during storage, and raw syrups were more susceptible than clarified syrups. Surface deterioration was mainly fungal since bacterial growth was inhibited by low water activity. Juice clarification reduced the loss of fermentable sugars during the evaporation stage and, generally, allowed for better storage of syrup up to 80 days. Target clarification pH had a dramatic effect on the storage of clarified 70 Brix syrups with more acidic pHs reducing fungal deterioration. Further studies are now warranted on the post-evaporation pH adjustment of raw and clarified syrups to <6.1 for long-term storage. Inexpensive soy bean oil and candellila wax showed promise as surface sealants to preserve syrups for at least 80 days of storage at ∼25 °C, also warranting further investigation.     

抽油机光杆电控加载及功图再现系统的研制

针对当前抽油机出厂检验和型式试验中采用在驴头悬点加载重锤的方法进行试验的问题,研发了抽油机光杆电控加载及功图再现系统,解决了抽油机光杆弹性变形带来的功图形变的问题,使抽油机上下冲程的载荷得到控制,并可将现场抽油机的功图完整再现到试验抽油机的工作上,保证了抽油机检验试验的准确性。该系统能够在非井场实现真实油井的光杆载荷和位移,得到与现场抽油机同样工况,便于抽油机出厂前的检验以及示功图设备的实际检测,为实现油田数字化管理技术的进步提供保障。     

[设计与优化]动车组车体端墙粒子阻尼器减振的数值分析与实验研究

动车组车体端墙的振动及其带来的辐射噪声会直接影响动车乘坐的舒适性以及列车高速运行时的平稳性,甚至造成结构疲劳失效。针对端墙结构在40 Hz激励频率处异常振动的问题,提出一种基于粒子阻尼技术的端墙减振方法。建立端墙粒子阻尼器的离散元模型,并根据粒子系统耗能大小,对阻尼器布置方案和分层数进行优化,通过实验分析了各减振方案下端墙的加速度响应。实验数据表明,安装粒子阻尼器后,端墙在40 Hz激励频率处主振方向的减振率可达80%以上,该结果也验证了理论和仿真模型的正确性。     

抽水蓄能机组空载工况分数阶PID调节控制

抽水蓄能机组运行在低水头空载工况易进入"S"特性区域,进而引起机组频率大范围波动和运行不稳定。针对传统比例—积分—微分(PID)控制在低水头空载工况下不能较好地调节抽水蓄能机组频率波动的不足,基于全特性曲线对数曲线投影变换的水泵水轮机数学模型,提出了适用于抽水蓄能机组低水头空载工况运行的分数阶PID(FOPID)调节系统模型,并运用粒子群优化算法优化FOPID控制参数,重点讨论了FOPID控制在低水头空载开机和空载频率扰动时的应用。仿真分析表明:相较于传统PID控制,FOPID控制使得低水头空载运行时机组频率和导叶开度的过渡过程有了明显的改进,提高了抽水蓄能机组调节系统的速动性与稳定性。     

温度对高速动车组侧窗抗风压载荷性能的影响

通过测量分析-50℃~40℃范围内不同温度下高速动车组侧窗玻璃和铝合金窗框的应力变化及整体车窗的密封性,研究温度对高速动车组侧窗抗风压载荷性能的影响。结果表明,温度对高速动车组侧窗的应力分布具有一定影响,在低温下侧窗玻璃的角点位置应力最大,在高温下侧窗玻璃的长边中部位置应力最大。在-50℃~40℃范围内,现有设计的侧窗可以承受±6000Pa风压载荷作用,保持车窗结构完好,密封性能良好。     

含有分子筛次级结构的多孔支撑体的制备及表征

以丝光沸石(MOR)分子筛为原料,采用冷等静压-固态粒子烧结法制备分子筛膜用含有MOR次级结构的多孔支撑体。分别采用氮气渗透通量、开孔孔隙率、抗压强度、平均孔径及孔径分布、热膨胀系数、X射线衍射(XRD)、拉曼(Raman)光谱、扫描电镜(SEM)等表征多孔支撑体的性能。结果表明,氮气渗透通量、开孔孔隙率随煅烧温度升高和煅烧保温时间延长而降低;抗压强度则与之相反;平均孔径随煅烧温度升高变大,孔径分布随原料粒径分布变窄而变窄;保留了原料中MOR的四、五和八元环等次级结构;次级结构的存在及较低的热膨胀系数(10-6℃-1级别)使得在其表面制备的MOR分子筛膜具有良好的耐热稳定性。     

IV‐BASED COINTEGRATION TESTING IN DEPENDENT PANELS WITH TIME‐VARYING VARIANCE

The distributions of cointegration tests are affected when the innovation variance varies over time. In panels, one must also pay attention to dependence among units. To obtain a panel cointegration test robust to both heteroskedasticity and dependence, we adapt the nonlinear instruments method proposed for the Dickey–Fuller test by Chang (2002, J Econometrics 110, 261–292) to an error‐correction framework. We show that IV‐based testing of the no error‐correction null in individual equations yields standard normal test statistics when computed with heteroskedasticity‐robust standard errors. The result holds under endogenous regressors, irrespective of the number of integrated covariates and for any variance profile. A non‐cointegration test combining single‐equation tests retains these nice properties. In panels of fixed cross‐sectional dimension, such test statistics from individual units are shown to be asymptotically independent even under dependence, leading to panel tests robust to dependence and heteroskedasticity. The tests perform well in finite panels.     

BETES:一种中文长文档抽取式摘要方法

文本摘要在自然语言处理领域是最重要的研究工作之一,并随着深度学习的兴起成为研究热点,而中文长文本的摘要抽取面临更大的挑战,存在长文本-摘要语料库不足、摘要抽取信息不准确、目标摘要冗余、摘要句缺失等问题.本文以中文长文本的摘要抽取为研究对象,提出一种BETES方法,基于规则和人工辅助筛选构建中文长文本-摘要语料库;利用B...     

房地产品牌传播中的人文关怀意识

房地产品牌传播中关注的不仅仅是房子,而是要以人文关怀的眼光去发掘、发现全新的更有价值的方式。文章通过对房地产广告进行分析,从房屋建筑设计、房地产广告设计和房地产销售三个方面分别阐述了"人文关怀"的理念,最后从四个方面论述了应如何将"人文关怀"的理念更好地融入房地产品牌传播之中。     

空调室外机与旧建筑立面改造设计

为空调室外机制约下的旧建筑立面改造设计提供一些方法,通过对分体式空调特点研究以及相关设计实践的总结,归纳出适应空调室外机的旧建筑立面改造方法。