Preparation of Human Milk Fat Substitutes from Lard by Lipase‐Catalyzed Interesterification Based on Triacylglycerol profiles

Human milk fat substitutes (HMFSs) with triacylglycerol profiles highly similar to those of human milk fat (HMF) were prepared from lard by physical blending followed by enzymatic interesterification. Based on the fatty acid profiles of HMF, different vegetable and single‐cell oils were selected and added to the lard. Blend ratios were calculated based on established physical blending models. The blended oils were then enzymatically interesterified using a 1,3‐regiospecific lipase, Lipozyme RM IM (RML from Rhizomucor miehei immobilized on Duolite ES562; Novozymes A/S, Bagsværd, Denmark), to approximate HMF triacylglycerol (TAG) profiles, particularly with respect to the distribution of palmitic acid in the sn?2 position. The optimized blending ratios were determined to be: lard:sunflower oil:canola oil:palm kernel oil:palm oil:algal oil:microbial oil = 1.00:0.10:0.50:0.13:0.12:0.02:0.02. The optimized reaction conditions were determined to be: enzyme load of 11 wt%, temperature of 60 °C, water content of 3.5 wt%, and reaction time of 3 hours. The resulting product was evaluated for total and sn?2 fatty acids, polyunsaturated fatty acids, and TAG composition. A high degree of similarity was obtained, indicating the great potential of the product as a fat alternative for use in infant formulas.     

相对分子质量对等规聚丙烯性能的影响

选取了6个相对分子质量不同的等规聚丙烯(i PP),研究了相对分子质量对i PP特性黏数和熔体流动速率的影响,并探讨了相对分子质量对i PP力学性能的影响规律。结果表明:i PP的特性黏数和熔体流动速率分别与重均分子量成0.78,-3.84次方关系,特性黏数与熔体流动速率成-0.200次方关系。随着i PP相对分子质量的减小,其弯曲强度、弯曲模量和拉伸强度先增大后减小,而断裂拉伸应变和悬臂梁缺口冲击强度单调递减。     

气相色谱法检测液化石油气中各组分和二甲醚含量分析

本文采用二甲醚专用分析柱对二甲醚和液化石油气组分含量进行气相色谱法分析。实验表明,该方法对二甲醚、C2、C3、C4以及C5各组分都有良好的分离效果,测定结果回收率在98.46%~102.36%,有较好的准确度和精密度;同时能够满足标准《SH/T 0230-1992》对色谱柱的分离要求和实验结果的精密度要求。     

形变组织对水电用高强度贝氏体钢再加热奥氏体晶粒长大的影响

对某水电用800 MPa调质贝氏体高强钢进行了热变形-热处理晶粒长大的实验室联合试验。采用Gleeble-3500热力模拟试验机对钢试样进行不同工艺热压缩变形后冷却至室温,随后对试样进行模拟淬火再加热,在900～1200℃不同温度和保温时间条件下奥氏体化,研究热变形组织的差异对重新奥氏体化晶粒长大的影响规律。结果表明,不同应变速率(0.01～10 s^-1)、变形温度(900～1150℃)和60%工程应变下,试验钢获得的变形组织大致可分为3类：带有明显变形特征的组织、均匀细小的完全再结晶组织和已长大粗化的再结晶组织。3类组织再加热过程中其晶粒长大趋势基本相同,起始晶粒尺寸越大则最终奥氏体晶粒尺寸越大;但在950℃等温时,带有明显变形特征组织的变形试样奥氏体晶粒先缓慢长大后又迅速长大粗化。经评估验证,所建立的Sellars模型、Beck模型和Hillert模型晶粒长大动力学方程对于试验钢的奥氏体晶粒长大行为均有比较满意的预测效果。3类变形组织对应的Hillert模型及Sellars模型中奥氏体长大激活能基本相同,说明同一成分钢种的初始组织的差异并未显著影响晶粒长大机制...     

从新农村建设到乡村振兴的广东省实践探索

乡村的规划建设在我国具有重要的政治、经济、社会、文化、生态意义,是全面建成小康社会、美丽中国的关键一环。通过对乡村政策的梳理,整体分析了国家从“社会主义新农村建设”到“乡村振兴”政策演进的脉络和要求,从广东省的层面剖析了乡村规划建设政策推进的全过程,重点分析了从乡村规划编制到乡村振兴实施路径的实践探索。提出,广东省的乡村建设实践在村庄规划编制、乡村特色挖掘与塑造,以及共建共享共治机制等方面都有重要经验,形成了一系列可推广的新农村“组合抱团”规划建设、规划设计建设运营一体化建设、以“道”兴村的模式。同时指出,未来乡村振兴应该结合文化、产业进行更多的思考和总结,实现真正的城乡融合和美丽乡村。     

不同类型地震波作用下堆积体边坡动力响应及#br# 失稳特征研究

准确理解地震作用下堆积体边坡的动力响应及失稳特征,可以为边坡抗震设计及稳定性分析方法提供依据。为了探讨不同类型地震荷载作用下堆积体边坡的失稳特征及动力响应,该文开展室内振动台模型试验。分析不同加载波形条件下边坡失稳特征以及加速度放大系数随相对高程、无量纲加速度幅值和频率参数的变化规律。探讨堆积体边坡的典型失稳特征和相关的物理机制。结果表明,正弦波作用下堆积体边坡加速度放大系数沿相对高程增长而变化较小;汶川清平波和El-Centro波作用下边坡加速度放大系数沿边坡相对高程呈较明显增大趋势。无量纲参数对放大系数影响较弱。当振动荷载达到边坡破坏的临界荷载时,边坡在短时间内即出现失稳破坏,破坏具有突发性,失稳模式具有典型的震裂-溃散型滑坡模式。在地震动力荷载作用下边坡位移变形可分为两个典型阶段：微变形阶段和急速上升大变形阶段。就该文3种波而言,在相同波峰幅值条件下,相同持续时间内正弦波所携带的总能量最大,最易使边坡失稳。     

Rare Variants in Genes Encoding MuRF1 and MuRF2 Are Modifiers of Hypertrophic Cardiomyopathy

Modifier genes contribute to the diverse clinical manifestations of hypertrophic cardiomyopathy (HCM), but are still largely unknown. Muscle ring finger (MuRF) proteins are a class of muscle-specific ubiquitin E3-ligases that appear to modulate cardiac mass and function by regulating the ubiquitin-proteasome system. In this study we screened all the three members of the MuRF family, MuRF1, MuRF2 and MuRF3, in 594 unrelated HCM patients and 307 healthy controls by targeted resequencing. Identified rare variants were confirmed by capillary Sanger sequencing. The prevalence of rare variants in both MuRF1 and MuRF2 in HCM patients was higher than that in control subjects (MuRF1 13/594 (2.2%) vs. 1/307 (0.3%), p = 0.04; MuRF2 22/594 (3.7%) vs. 2/307 (0.7%); p = 0.007). Patients with rare variants in MuRF1 or MuRF2 were younger (p = 0.04) and had greater maximum left ventricular wall thickness (p = 0.006) than those without such variants. Mutations in genes encoding sarcomere proteins were present in 19 (55.9%) of the 34 HCM patients with rare variants in MuRF1 and MuRF2. These data strongly supported that rare variants in MuRF1 and MuRF2 are associated with higher penetrance and more severe clinical manifestations of HCM. The findings suggest that dysregulation of the ubiquitin-proteasome system contributes to the pathogenesis of HCM.     

逐级加载下浅埋软岩隧道动力破坏振动台试验

浅埋隧道围岩的质量普遍较低,整体稳定性差,隧道震害表明强震作用下浅埋隧道极易发生震动破坏。通过开展V级围岩条件下浅埋隧道在小震下的震动响应和逐级加载下的震动垮塌振动台试验,研究了小震作用下围岩加速度沿地层的分布、衬砌结构的内力变化和围岩内部的水平位移变化规律,强震作用下衬砌结构裂缝开展和围岩震动垮塌。结果表明:围岩加速度随距地表距离的减小而增加,地表加速度约为拱顶处加速度的1.63倍,相同高度平面内靠近隧道的围岩振动具有一定的加强;隧道拱顶围岩内部的水平位移大约是拱腰围岩内部的1.23倍,围岩内部位移随着远离隧道而逐渐减小,随着震动烈度的增加而不断增加;隧道拱顶上方垮塌区形状近似漏斗,震动引起隧道衬砌结构拱脚处的轴力和弯矩变化最大,且拱肩和拱脚处裂缝分布最多,应加强拱肩和拱脚处结构的抗震性能。     

掺防冻剂水泥净浆、砂浆、混凝土间减水率关系研究

用流变学原理探讨了掺防冻剂新排水泥净浆、砂浆、混凝土之间的减水率关系,将黑龙江省防冻剂分为高、中、低减水率型,建立了三种浆体的水布比与减水率间的回归方程。