FAME Production and Fatty Acid Profiles from Moist Chlorella sp. and Nannochloropsis oculata Biomass

In the present study, we investigated the production of fatty acid methyl esters (FAME) from moist Chlorella sp. and Nannochloropsis oculata biomass using a hydrolysis–esterification process. Additionally, we evaluated for the first time the fatty acid profile before and after this process. Hydrolysis of the lipid fraction was performed on a moist biomass in the presence of differing amounts of an acid catalyst in both 50 and 100 % w/w water relative to the biomass. The esterification of the crude extracts of the free fatty acids (FFA) was then investigated. The experiments show that in the presence of 50 % w/w water relative to the biomass, the hydrolysis–esterification process results in higher FFA and FAME yields. The analysis of the fatty ester profiles did not reveal any degradation of the FFA from the microalgae biomass under the hydrolysis–esterification conditions. The results were compared with both extraction–transesterification and direct transesterification processes using dry biomass. The extraction–transesterification and hydrolysis–esterification processes resulted in similar FAME yields and similar profiles of the fatty esters from dry and moist biomass materials, respectively.     

交联聚丙烯酰胺纳米微球的制备及性能评价

以丙烯酰胺(AM)单体水溶液为分散相,Span80/Tween80为乳化剂,煤油为分散介质,绘制了AM/H2OSpan80/Tween80-煤油体系的拟三元相图。依据拟三元相图配制了含油相质量分数52.0%、Span80/Tween80(质量比4∶1)复合乳化剂质量分数7.8%、水相质量分数40.2%的W/O微乳液(以体系总质量计),在70℃利用反相微乳液聚合法制备了纳米级交联聚丙烯酰胺微球。结合激光衍射粒度分析仪(LPSA)探讨了交联剂、引发剂用量及搅拌速率等合成条件对交联PAM微球粒径及吸水溶胀性能的影响,并采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)对微球形貌进行了表征,确定具有较高吸水倍率的交联PAM微球的优化合成条件为:交联剂(N,N-亚甲基双丙烯酰胺)MBA用量0.60%、引发剂(过硫酸铵)APS用量0.50%(以单体质量计)、搅拌速率1 000r/min。溶胀实验显示,该条件下合成的微球在1.0×105mg/L矿化度地层水中吸水倍率为1 690,表现出良好的耐盐性,高吸水倍率。SEM和TEM结果显示,微球具有较好的球形度、单分散性好,粒径分布较为均一,约为150~200 nm。岩心封堵实验表明,聚合物微球胶乳对地层有良好的封堵性,具有封堵、突破、深入、再封堵的逐级调剖特性。     

Docosahexaenoic Acid Levels in Blood and Metabolic Syndrome in Obese Children: Is There a Link?

Prevalence of metabolic syndrome is increasing in the pediatric population. Considering the different existing criteria to define metabolic syndrome, the use of the International Diabetes Federation (IDF) criteria has been suggested in children. Docosahexaenoic acid (DHA) has been associated with beneficial effects on health. The evidence about the relationship of DHA status in blood and components of the metabolic syndrome is unclear. This review discusses the possible association between DHA content in plasma and erythrocytes and components of the metabolic syndrome included in the IDF criteria (obesity, alteration of glucose metabolism, blood lipid profile, and blood pressure) and non-alcoholic fatty liver disease in obese children. The current evidence is inconsistent and no definitive conclusion can be drawn in the pediatric population. Well-designed longitudinal and powered trials need to clarify the possible association between blood DHA status and metabolic syndrome.     

Evaluation of Antioxidant,Antidiabetic and Anticholinesterase Activities of Smallanthus sonchifolius Landraces and Correlation with Their Phytochemical Profiles

The present study aimed to investigate the phytochemical profile of leaf methanol extracts of fourteen Smallanthus sonchifolius (yacon) landraces and their antioxidant, anticholinesterase and antidiabetic activities that could lead to the finding of more effective agents for the treatment and management of Alzheimer’s disease and diabetes. For this purpose, antioxidant activity was assessed using different tests: ferric reducing ability power (FRAP), 2,2-diphenyl-1-picryl hydrazyl (DPPH), nitric oxide (˙NO) and superoxide (O₂˙⁻) scavenging and lipid peroxidation inhibition assays. Anticholinesterase activity was investigated by quantifying the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, whereas antidiabetic activity was investigated by α-amylase and α-glucosidase inhibition tests. To understand the contribution of metabolites, phytochemical screening was also performed by high performance liquid chromatography-diode array detector (HPLC-DAD) system. Among all, methanol extract of PER09, PER04 and ECU44 landraces exhibited the highest relative antioxidant capacity index (RACI). ECU44 was found to be rich in 4,5-di-O-caffeoylquinic acid (CQA) and 3,5-di-O-CQA and displayed a good α-amylase and α-glucosidase inhibition, showing the lowest IC₅₀ values. Flavonoids, instead, seem to be involved in the AChE and BChE inhibition. The results of this study revealed that the bioactive compound content differences could be determinant for the medicinal properties of this plant especially for antioxidant and antidiabetic activities.     

基于膨胀波纹管的单一井径钻井技术

随着勘探开发越来越多地进入深部地层,钻井技术面临着如何在保证井眼足够大的情况下钻至预定井深,减少钻井时间和成本等问题,而单一井径技术的发展为解决这些复杂情况提供了新的解决途径。单一井径技术是在膨胀管技术基础上发展起来的始终保持同一井径的新兴技术。介绍了膨胀波纹管技术和单一井径技术的现状,提出了一种膨胀波纹管实现单一井径技术,分析了制约膨胀波纹管技术实现单一井径的技术难题并提供了一些解决方案。     

海上稠油油藏“调驱+热采”提高采收率实验研究

渤海稠油油藏具有原油黏度高、油层渗透率高和非均质性严重等特点,常规注水开采时油井产能低,开发效果差,亟待采取强化措施来改善水驱开发效果。以油藏工程、物理化学和热力学等理论为指导,以仪器分析、化学分析和物理模拟等为技术手段,以渤海NB35-2油藏储层地质和流体为实验平台,开展了调驱、热力采油和"调驱+热力"联合作业增油效果实验研究和机理分析。结果表明,与采用蒸汽发生器向岩心内注入高温高压蒸汽的实验方法相比,通过在岩心中不同区域饱和不同黏度原油来模拟热流体注入即热采过程,不仅能够更好地模拟热采过程中储层内原油黏度分布,而且技术简单。与单独热采或调驱措施相比较,"调驱+热采"联合作业增油效果较好,并且采收率增幅大于二者之和,产生了协同效应。"调驱+热采"联合作业优化工艺参数:Cr~(3+)聚合物凝胶段塞尺寸范围为0.025PV~0.075 PV,C_P为1 200~1 600 mg/L,m(聚):m(Cr~(3+))=(180:1)~(270:1)。热流体作用范围小于3/10注采井距,作用范围内原油黏度50~120mPa·s。     

巨厚块状稠油油藏高温调剖技术研究与应用

厚块状稠油油藏往往在开发过程中油层动用程度严重不均,汽窜现象突出,开发效果差,为此,结合辽河油田巨厚块状稠油油藏特点,开展了高温调剖技术研究,确定了调剖剂配方。矿场试验表明,研制的高温调剖剂能够封堵高渗油层,同时注入驱油助排剂对低渗油层进行驱油助排,达到了改善吸汽剖面、提高油层纵向动用程度、改善蒸汽吞吐效果的目的。     

K波段宽带螺旋天线设计

从理论上分析了螺旋天线的设计原理,利用阿基米德螺旋天线实现了一款K波段的高频宽带螺旋天线,使高频天线拥有更轻的质量,更低的剖面及更好的圆极化性。最后通过仿真软件CST设计了一款带宽覆盖18.0~26.5GHz的阿基米德螺旋天线,涵盖了整个K波段。结果表明,该天线在整个频段电压驻波比<2,能很好的满足天线收发要求。     

铜柱凸块生产关键工艺技术研究

讨论了铜柱凸块生产工艺中籽晶层厚度和电镀电流密度等关键制程因素对铜柱凸块共面性、晶圆应力、凸块剖面结构和电镀效率等方面的影响.研究结果表明增加电镀籽晶层厚度可以提高凸块共面性;在相同电镀电流密度下,籽晶层越厚,晶圆应力越大;相同的籽晶层厚度下,随着电镀电流密度增加,晶圆应力增加,但增加速率逐渐变慢;低电流密度下铜柱凸块顶部形成盘碟形状的剖面结构,而高电流密度容易使铜柱顶部形成圆拱剖面结构;采用阶梯电镀速率电镀方法与均一慢电镀速率电镀出的铜柱凸块共面性一致,而采用阶梯电镀法既能够提高电镀效率又可以得到较好的铜柱顶部盘碟形剖面结构.     

基于ANMF和非线性映射距离扩展目标检测

针对距离扩展目标的检测问题,提出一种自适应归一化匹配滤波（ANMF）、非线性映射和高阶互相关积累（HOCC）相结合的目标检测方法。首先将距离像按慢时间进行脉冲维划分,得到若干脉冲子区间,再对每个脉冲子区间进行自适应归一化匹配滤波,然后利用非线性函数对滤波的输出进行非线性映射处理,最后将非线性映射的输出进行高阶互相关积累,从而获得检测统计量。仿真实验结果表明,在检测概率为80％时,所述方法比传统 ANMF 方法所需的信杂比低1 dB 左右,性能较为优越。