多孔网状HMX的制备与表征

将奥克托今(HMX)溶于二甲基亚砜(DMSO)中,获得HMX/DMSO络合物晶体,再将其分别加入蒸馏水和含聚乙烯吡咯烷酮(PVP)的溶液中,制备了A类多孔网状HMX(PHMX-A)和B类多孔网状HMX(PHMX-B)。用扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)、压汞分析仪及TG-DSC热分析仪对多孔网状HMX进行了表征。结果表明:多孔网状HMX由众多的孔和均匀连续的骨架构成,具有高的比表面积和孔隙率。PHMX-A全部为型晶体,其比表面积为5.3m2·g-1,平均孔径为501nm,孔隙率为56.1%;而PHMX-B有80%为型晶体,含少量的γ型晶体,其比表面积为19.0m2·g-1,平均孔径为75nm,孔隙率为37.2%。与HMX原料相比,PHMX-A和PHMX-B的相转变温度分别提前了2.8℃和17.5℃,其热分解温度分别提前了0.3℃和1.3℃,而其热失重开始温度分别提前了4℃和14℃。     

热采井网状胶结复合防砂技术研究

热采井网状胶结复合防砂技术是在不下筛管的情况下,在携砂液中填加纤维胶结砂和网络剂的方法,充填油层后,在充填层中靠其接触压力和摩擦力的相互作用,达到力学平衡,进而形成网状纤维阻挡,以此防止砂子返排,达到防砂的目的。热采井网状胶结复合防砂技术研究的关键是筛选出优质纤维和网络剂,并建立与其配套的工艺流程,纤维必须具备耐高温,具有良好的机械强度,同时兼备良好的分散性。应用表明,该技术具有很好的防砂效果,且对地层伤害小,有利于提高油井产量。     

双曲网壳地震作用下的双参数破坏准则

考虑网格形式和高跨比的变化,用有限元软件ANSYS对多个单层双曲抛物面网壳算例进行地震时程分析。采用全过程动力响应分析方法研究其失效特点,利用建筑结构基于位移和能量的双参数破坏准则的模式,将结构最大位移与塑性累积耗能进行组合建立了动力强度破坏的双参数准则,以动力破坏指标判定结构的动力破坏程度。与原有网壳结构动力破坏准则相比,应用双参数准则和动力破坏指标可以更有效地评价单层双曲抛物面网壳在地震作用下的动力强度破坏程度。     

Palmitic Acid-Induced Neuron Cell Cycle G2/M Arrest and Endoplasmic Reticular Stress through Protein Palmitoylation in SH-SY5Y Human Neuroblastoma Cells

Obesity-related neurodegenerative diseases are associated with elevated saturated fatty acids (SFAs) in the brain. An increase in SFAs, especially palmitic acid (PA), triggers neuron cell apoptosis, causing cognitive function to deteriorate. In the present study, we focused on the specific mechanism by which PA triggers SH-SY5Y neuron cell apoptosis. We found that PA induces significant neuron cell cycle arrest in the G₂/M phase in SH-SY5Y cells. Our data further showed that G₂/M arrest is involved in elevation of endoplasmic reticular (ER) stress according to an increase in p-eukaryotic translation inhibition factor 2α, an ER stress marker. Chronic exposure to PA also accelerates beta-amyloid accumulation, a pathological characteristic of Alzheimer’s disease. Interestingly, SFA-induced ER stress, G₂/M arrest and cell apoptosis were reversed by treatment with 2-bromopalmitate, a protein palmitoylation inhibitor. These findings suggest that protein palmitoylation plays a crucial role in SFA-induced neuron cell cycle G₂/M arrest, ER stress and apoptosis; this provides a novel strategy for preventing SFA-induced neuron cell dysfunction.     

新型立体式网状宫内节育器初步临床观察

为了观察新型立体式网状宫内节育器(3-DR-IUD)的避孕效果及副反应,将152例志愿受试者随机分为两组,即接受3-DR-IUD组和放置元宫药铜宫内节育器(2-D-IUD)组,每组各76例,常规放置3-DR-IUD和2-D-IUD。分别于术后1个月、3个月、6个月和12个月进行随访,了解放置宫内节育器(IUD)后副反应(如腹痛、腰痛、阴道出血持续时间及出血量、白带等)的发生率、带器妊娠率、IUD脱落率、因症取出率、续用率及避孕效果,并利用B超、X光腹部平片检查3-DR-IUD位置等。两组各76例均成功放置了IUD,术中均无明显疼痛。3-DR-IUD组术后出现白带增多、月经期延长、不规则出血、月经量增多及腰腹部疼痛等副反应6例(7.9%),而2-D-IUD组出现31例(40.8%),两组比较差异有统计学意义(P0.0001)。3-DR-IUD组无脱落,无带器妊娠者,3个月时因对硅橡胶过敏取出1例,12个月时终止率为1.3%,续用率为98.7%(75/76);2-DIUD组终止率为13.2%,续用率为86.8%(66/76),两组比较差异有统计学意义(P=0.009)。实验结果表明,3-DR-IUD具有很好的避孕效果,术后副反应轻微,可为育龄妇女提供新的、安全、高效的IUD。     

铝合金网状材料抑爆作用的试验验证

通过试验证明，爆炸容器内在充填铝合金网状材料后，可改变容器内腔形状。遏制压力波的传播；同时，也可吸收燃烧释放出的大部分热能，从而达到抑爆作用。     

面向少样本网状结构体的候选区域自适应检测方法

在仅有少量标签数据的图像网状结构检测任务中,需要大量训练数据的目标检测模型检测性能大幅下降。基于区域候选的目标检测模型在预测时,检测目标越多,检测时间越长。若基于区域候选的目标检测模型产生候选框的数量固定不变,而不同图像中网状结构目标数量不同,造成目标检测中额外的时间消耗。针对该问题,通过对训练样本中网状结构目标在图片中的密度分析以及根据网状结构体在图片中的特征分布,提出一种面向少样本网状结构体的候选区域自适应检测方法。该方法通过基于二值标签图标注方法得到大量训练样本,由候选区域自适应方法选取合理的候选框数量。与未改进的模型相比,在几乎不损失准确率的情况下,其加快了检测速度,尤其在目标数量稀少的数据中优势更为明显。     

Reviewing Rare Earth Succinate Frameworks from the Reticular Chemistry Point of View: Structures,Nets, Catalytic and Photoluminescence Applications

The intense development that Metal-Organic Frameworks have experienced along the last two decades, reflects the interest on these compounds as a new generation of multifunctional materials with diverse applications. The first works of Prof. Omar Yaghi devoted to obtain open frameworks by combining rigid aromatic linkers and a variety of metal centers, encouraged the creativity of the scientific community to designcoordination polymers employing aliphatic ligands as multitopic building blocks . Here, a revision of the literature dedicated to rare earth coordination networks mainly based in succinate ligand and derivatives is performed. A structural analysis of 2D and 3D frameworks based on rare earth elements and succinate, was carried out considering their inner connectivities and topologies with focus on those compounds with potential photoluminescent and catalytic technological applications. Thus, a variety of optical behaviours regarding the emission mechanisms, colours, lifetimes, quantum yields as well as chemical/thermal sensing properties are presented and compared with related phases found in literature. The catalytic performance of several rare earth-succinates in three important reactions is discussed in terms of their acidity, dimensionality and available active centers towards the formation of the desired products analysing parameters such as selectivity, yields and TOFs.     

球面网壳结构在强震下的失效机理

研究了球面网壳结构在地震等动力荷载作用下两种可能的失效机理 :由于几何非线性起主要作用导致的动力失稳和由于塑性变形过度发展导致的强度破坏。提出了统一的基于响应分析的关于网壳结构失效机理的理论框架。对单层球面网壳在简谐荷载和地震荷载作用下的失效机理进行了较系统的分析 ,提出了具体的动力失稳和强度破坏判别准则 ,求得了相应的极限荷载。取得的结果具有良好的规律性 ,验证了所提出的理论框架的合理性和实用性     

Increased GABAergic activity in the region of the pedunculopontine and deep mesencephalic reticular nuclei reduces REM sleep and impairs learning in rats.

Newly formed memories are initially fragile and require consolidation to be transformed into an enduring state. Memory consolidation may occur during increased postlearning REM sleep. REM deprivation during these periods (termed REM sleep windows [RSWs]) impairs subsequent performance. The pedunculopontine nucleus (PPT) and adjacent deep mesencephalic reticular nuclei (DpMe) have been implicated in the generation of REM sleep. Following 24-hr baseline recording, rats were trained on the 2-way avoidance task for 50 trials/day over 2 days and retested on Day 3. EEG was recorded 22 hr after training on training Days 1 and 2. Rats were injected with the GABAB agonist baclofen or saline into the PPT/DpMe region at 0300 to coincide with the start of a known RSW. Based on shuttle performance, saline rats were assigned post hoc to a learning group (LG) that avoided the footshock at least 60% at retest or nonlearning group (NLG) that performed below this criterion. Baclofen-injected rats were not assigned post hoc into separate groups as all rats performed below the learning criterion. PPN/DpMe infusions of the inhibitory GABAB agonist baclofen decreased REM and impaired subsequent memory performance. Normal GABAergic transmission in the PPN/DpMe may be necessary for REM to occur and for the consolidation of incentive learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)