微晶石墨与无烟煤浮沉特性研究

对内蒙古某无烟煤共伴生型微晶石墨采用酸法脱灰,根据浮沉法研究了微晶石墨与无烟煤的浮沉分离密度及不同密度级产物的产率分布,采用X射线衍射和拉曼光谱特征分析了浮沉分离后微晶石墨与无烟煤的矿物组成及拉曼特征.结果表明:以拉曼光谱参数AD/(AD +AG)值表征无烟煤基微晶石墨中无烟煤含量,并将AD/(AD+AG)值与浮沉试验中浮物累积产率比对,二者变化趋势具有较好的一致性,但受解离度影响.     

小胶质细胞对阿尔兹海默病发生发展的影响作用

阿尔兹海默病(老年性痴呆,AD)是由β淀粉样蛋白(Aβ)和微管相关蛋白(Tau)聚集形成的具有毒性作用的寡聚物而引起的老年人主要以记忆力下降和脑部形成老年斑、神经纤维缠绕为特征的神经退行性疾病. 小胶质细胞作为中枢神经系统中的固有免疫细胞,是脑内免疫监视的关键成分,发挥内源性免疫防御作用. 正常生理状态的小胶质细胞能有效吞噬和清除毒性Aβ寡聚体,阻止AD发生. 在AD病理过程中,过度激活的小胶质细胞通过补体依赖途径过度吞噬突触,导致突触丧失,同时大量释放炎症因子,促进Tau相关病理变化,对神经元造成直接损伤,导致认知功能下降. 由此可见,小胶质细胞在AD发生发展过程中起着双刃剑的作用,探明小胶质细胞的极化状态及其在AD疾病机理中的作用将为攻克AD的药物研发提供突破性思路.     

铜盐和碳黑对微烟NEPE推进剂燃烧性能的影响

通过测定不同压力下推进剂的燃烧性能及熄火表面元素分析,研究了两种铜盐（AD和BC）和3种碳黑对微烟NEPE推进剂燃烧性能的影响.结果表明,适量AD可改善推进剂的燃烧性能,使推进剂在3～20 MPa压力范围内的压强指数降至0.45以下;AD在12～18 MPa压力范围内比等量BC对微烟NEPE推进剂燃烧性能的催化作用弱,这可能与AD所含铜元素在燃面的富集程度小于BC有关.3种碳黑均能改变微烟NEPE推进剂在3～18 MPa压力范围内的燃速.增加乙炔碳黑含量可使推进剂在3～20 MPa压力范围内的燃速提高,压力指数降低.     

Amyloid cross-seeding between Aβ and hIAPP in relation to the pathogenesis of Alzheimer and type 2 diabetes

Amyloid cross-seeding of different amyloid proteins is considered as a highly possible mechanism for exacerbating the transmissible pathogenesis of protein misfolding disease(PMDs) and for explaining a molecular link between different PMDs, including Alzheimer disease(AD) and type 2 diabetes(T2D),AD and Parkinson disease(PD), and AD and prion disease.Among them, AD and T2D are the most prevalent PMDs, affecting millions of people globally, while Aβ and hIAPP are the causative peptides responsible for AD and T2D, respectively.Increasing clinical and epidemiological evidences lead to a hypothesis that the cross-seeding of Aβ and hIAPP is more biologically responsible for a pathological link between AD and T2D.In this review, we particularly focus on(i) the most recent and important findings of amyloid cross-seeding between Aβ and h IAPP from in vitro, in vivo, and in silico studies,(ii) a mechanistic role of structural compatibility and sequence similarity of amyloid proteins(beyond Aβ and hIAPP)in amyloid cross-seeding, and(iii) several current challenges and future research directions in this lessstudied field.Review of amyloid cross-seeding hopefully provides some mechanistic understanding of amyloidogenesis and inspires more efforts for the better design of next-generation drugs/strategies to treat different PMDs simultaneously.     

提高FTF12E3+AD型加弹机自动落筒成功率

介绍FTF12E3+AD型加弹机自动落筒系统,分析其优势和目前存在的设计缺陷,分别对自动络筒系统的皮辊轴、废丝管歧管等部件的设计形式、材质提出新的改进思路,并进行了实际的改造,总结了改造效果。     

响应面法优化阳离子Gemini表面活性剂的微波合成工艺

以溴代十四烷和四甲基乙二胺为原料,以无水乙醇为溶剂,用微波辐射法合成一种双(二甲基十四烷基)乙撑-双季铵盐双子表面活性剂。通过响应面分析法得出了拟合方程式:Y=64.00+0.70A+4.04B+0.34C+3.87D+0.42AB-0.30AC+0.72AD+4.13BC+1.58BD+0.00CD-6.37A~2-4.38B~2-3.78C~2-6.34D~2。结果表明合成反应的最佳工艺条件为:溴代十四烷与四甲基乙二胺的摩尔比为2.7∶1,反应时间为25 min,反应温度为82℃,微波功率为270 W时,产率为64.50%,与预测值(66.41%)相比,相对误差为2.88%。     

基于ATmega16的AD7705多通道模拟量采集系统设计

设计了以单片机ATmega 16为控制核心,以AD7705为前端采集芯片,以CPLD芯片EPM3064为逻辑开关阵列的32通道模拟量采集系统.给出了相应的硬件电路、驱动程序以及应用软件,指出了AD7705在实际应用中应当注意的一些问题.该采集系统结合测量仪器可以完成多点多参数的测量.     

相图与耐火材料(Ⅵ)

(接上期)7三元交互(交换)体系0*如果四种物质存在互换反应:AB+CD幑幐AD+CB,则这种体系称为三元交互(或交换)体系,其相图称为四角相图。对于这种互换反应体系,只要确定其中两种物质的浓度变量,就可算出其全部组元的组成。7.1三元交互体系的组成表示方法三元交互体系在恒压时的最大自由度f=C-P     

新型集成仪表放大器及其应用

介绍了ADI公司最新推出的新型高性能仪表放大器OP7X7,AD623（AD627）,AD629,AD855X／AD857X的性能特点、主要技术指标及应用电路。     

基于FPGA与AD7985的脉冲电源数据采集设计

为了满足精密电镀的控制需求,设计了一种基于FPGA和AD7985的高速高精度的数据采集系统,该数据采集系统可应用于高精度的脉冲电镀电源中,用于采集输出脉冲的电流和电压参数并用于电流调控.首先设计分析了采集系统的主要硬件电路,包括隔离放大电路、电压跟随电路和AD转换电路;然后对AD7985的控制时序进行了研究,给出了控制...     

浅谈AD特殊单立管排水系统

为研究AD型特殊单立管排水系统的优势,对它和普通的排水系统进行了比较分析,结果表明AD型特殊单立管排水系统提高了通水能力具有良好的水力工况,且节省了管材,缩小管道井面积.因此它符合当前节能,节水,节地,节材的国策,具有良好的使用前景.     

四角相图及其应用

如果四种物质存在离子互换反应(互易反应):AB+CD(?)AD+CB,则这四种物质可以用其中任意三种来表示。因为第四种物质可由反应方程确定。这种系统叫互易三元系(Reciprocal Ternary System)或准三元系(Quasi-ternary System),其相图习惯上称四角相图。四角相图作为描述熔盐的相平衡关系,早已得到广泛、普遍的应用。但在陶瓷材料     

响应曲面法优化锡酸钠合成工艺

以锡为原材料，温度、碱质量分数、氧化剂质量分数和氧化剂滴速为考察因素，采用Box-Behnken的中心组合试验设计和响应曲面分析法对锡酸钠合成工艺进行研究，并建立关于锡转化率的预测模型。结果表明：锡反应转化率(Y)=16.02-1.53A+1.58B-6.91C+2.64D-0.0067AB-0.021AC+0.021AD+0.085BC-0.014BD+0.047CD+0.0022A²-0.022B²+0.21C²-0.019D²,模型决定系数R²=0.7291,拟合度较为显著。锡酸钠合成最佳反应工艺参数为温度79℃、碱质量分数17%、氧化剂质量分数16%、氧化剂滴加速度4mL/min,此条件试验锡转化率达到99.17%。因素分析表明：温度和碱质量分数对锡酸钠合成锡的转化率影响较为显著。     

静注人免疫球蛋白在治疗阿尔茨海默病中的应用

阿尔茨海默病(Alzheimer disease,AD)是最常见的神经退行性疾病。AD已经造成了严重的社会负担,而且目前仍无有效的方法可以治疗。近年来,使用静注人免疫球蛋白(intravenous immunoglobulin,IVIg)治疗AD被认为是一种有潜力的疗法。本文对AD、Aβ级联假说、IVIg治疗AD的作用机制以及临床试验等作一综述,并对未来IVIg治疗AD的研究进行了展望。     

Effect on anaerobic digestion performance of corn stover by freezing–thawing with ammonia pretreatment

In order to enhance the biomethane production from corn stover, choosing effective pretreatment is one of the necessary steps before starting anaerobic digestion(AD).This study was aimed to analyze the effectiveness of freezing–thawing with ammonia pretreatment on substance degradation and AD performance of corn stover.Three ammonia concentrations(2%, 4%, and 6%) with two different moisture contents(50% and 70%) were used to pretreat the corn stover at two temperatures(-20 ℃ and 20 ℃).The result showed that an optimum pretreatment condition for corn stover was at the temperature of -20 ℃, moisture content of 70% and ammonia concentration of 2%.Under the optimum pretreatment condition, the maximum biomethane yield reached 261 ml·(g VS)~(-1), which was 41.08% higher than that of the untreated.Under different pretreatment conditions,the highest loss of lignin at -20 ℃ with 2% ammonia concentration was 63.36% compared with the untreated.The buffer capacity of AD system was also improved after the freezing–thawing with ammonia pretreatment.Therefore, the freezing–thawing with ammonia pretreatment can be used to improve AD performance for corn stover.This study provides further insight for exploring an efficient freezing–thawing with ammonia pretreatment strategy to enhance AD performance for the practical application.     

基于中试规模条件分枝杆菌降解甾醇侧链的初步研究

微生物降解甾醇侧链得到的产物雄甾4-烯-3,20-二酮(AD)和雄甾1,4-二烯-3,17-二酮(ADD),是多数甾类药物的中间体,有着广阔的发展前景.本文在500 L发酵罐的中试规模上,对分枝杆茵降解(Mycobacterium SP MB 3683)大豆甾醇侧链至AD的种子pH、移种时机及发酵过程pH控制进行了初步研究,结果表明:在投料浓度2%,转化时间96 h的条件下,AD的含量达1.153%,转化率为57.6%.     

多通道热电阻精密测量中温度漂移的补偿法

针对温度测量过程中的温度漂移问题,分别从温度传感器的选取、测量方案的设计、实际测量电路和滤波算法4个方面给出了具体的解决方案.详细阐述了后级两级AD623信号放大及调理电路和AD转换电路的设计方案,并给出了它与微控制器的应用接口电路.实际应用表明,该方案满足分辨率为±0.1℃、准确度为±0.2℃的设计要求.     

Kinetic parameter estimation for cooling crystallization process based on cell average technique and automatic differentiation

In this paper, a cell average technique(CAT) based parameter estimation method is proposed for cooling crystallization involved with particle growth, aggregation and breakage, by establishing a more efficient and accurate solution in terms of the automatic differentiation(AD) algorithm. To overcome the deficiency of CAT that demands high computation cost for implementation, a set of ordinary differential equations(ODEs) entailed from CAT based discretized population balance equation(PBE) are solved by using the AD based high-order Taylor expansion. Moreover, an AD based trust-region reflective(TRR) algorithm and another interior-point(IP) algorithm are established for estimating the kinetic parameters associated with particle growth, aggregation and breakage. As a result, the estimation accuracy can be further improved while the computation cost can be significantly reduced, compared to the existing algorithms. Benchmark examples from the literature are used to illustrate the accuracy and efficiency of the AD-based CAT, TRR and IP algorithms in comparison with the existing algorithms. Moreover, seeded batch cooling crystallization experiments of β form L-glutamic acid are performed to validate the proposed method.     

阿尔兹海默症药物研究进展

阿尔兹海默症的高发病率及全球人口老龄化使其成为亟待解决的重大问题。近年来,对AD的发病机制研究显著增多,通过研发新型AD治疗药物对AD发病进程进行延缓和治愈的研究也愈发增多。总结近五年来AD药物的相关文献,并结合目前AD药物的研发情况,对AD药物研究进展及药物研发情况进行综述,以期为后续该病的药物研发提供一定的参考。     

天然产物治疗阿尔茨海默病的研究进展

阿尔茨海默病(Alzheimer's disease, AD)是一种致死性的慢性神经退行性疾病,迄今尚无有效的治愈方法。多种从中药中提取到的天然产物被报道有很好的抗AD活性,包括黄酮类、萜类、生物碱和蒽醌等,它们从多方面可以有效缓解AD的症状。本文主要综述了这些类型的天然产物对抗AD的药理活性及作用机制,为今后研究者进一步研究它们的抗AD活性提供依据。