脂肪醇对环氧乙烷环氧丙烷嵌段共聚物破乳效果的影响—Ⅰ.W/O型乳状液的破坏

现时国内外的原油破乳剂品种繁多,但就其组成而言,主体都是环氧乙烷(EO)和环氧丙烷(PO)的嵌段共聚物。我们曾对这类破乳剂的破乳规律进行过较系统的研究。为了进一步寻找提高破乳效果的途径,本文研究了正构脂肪醇对EO-PO共聚物破乳效果的影响。结果表明,加入适量的脂肪醇能大幅度提高破乳效率,效果最好的是正戊醇。     

磁性阳离子交换树脂的结构与性能分析

利用古埃磁天平法、扫描电镜、粉末Ｘ射线衍射以及分光光度法等检测了化学转化法制备的磁性阳离子交换树脂。结果表明,所制备的树脂内部磁性物质为Ｆｅ３Ｏ４,且在 树脂内部的孔道及表面分布均匀,均被封锁在树脂内部,因而,这类磁性树脂在碱性和中性盐溶液中具有较高的稳定性。此外,树脂的磁化过程并不影响其交换容量。     

The role of exosomal lncRNAs in cancer biology and clinical management

Exosomes play a vital role in cell–cell communication within the cancer microenvironment. Exosomal long noncoding RNAs (lncRNAs) are important regulators in cancer development and are involved in multiple processes, including cancer cell proliferation, angiogenesis, metastasis, drug resistance, and immunomodulation. Changes in the levels of exosomal lncRNAs often appear with the occurrence and development of cancer. Therefore, exosomal lncRNAs can be used as biomarkers for cancer diagnosis and prognosis. Exosomal lncRNAs can also indicate the treatment response of patients receiving chemotherapy. Moreover, exosomal lncRNAs are potential therapeutic targets for cancer treatment. In this review, we summarize the role of exosomal lncRNAs in cancer biology as well as in clinical management. A more comprehensive and in-depth understanding of the role of exosomal lncRNAs in cancer may help us better understand the mechanism of cancer development and clinically manage cancer patients.Subject terms: Cancer, Molecular biology     

Mindlin中厚板的辛求解方法

在Mindlin板混合能函数的基础上,通过引入混合变量及对混合能变分原理的修正,在全状态下建立了Mindlin板的Hamilton正则方程,进而采用直接法给出了两对边简支板的解析解,并通过具体例题说明了方法的有效性．     

Limit cycles in a food-chain with inhibition responses

In this paper, by constructing a Lyapunov function, we show the global asymptotical stability of a three-dimensional food-chain model with inhibition response. We then using a corollary to center manifold theorem to show that the system undergoes a 3-D Hopf bifurcation, and obtain the existence of limit cycles for the three-dimensional model. The methods used here can be extended to many other 3-D differential systems.     

基于MSP430的直线导轨定位装置的设计与实现

直线导轨是数控技术的重要组成部件,它的精确程度非常重要。以MSP430单片机为核心,设计了一个直线导轨精确定位装置。此装置采用两相四线的ST57型步进电机和60CM的螺纹丝杆组成一个直线导轨组,选用M7128驱动器驱动步进电机,使用PWM波精确定位算法程序精确控制电机转速。MSP430的IO端口控制步进电机的正反转,使得步进电机带动螺纹丝杆转动,让滚动丝杠上的物体往复移动,并在电脑上显示当前位移值。试验证明,其定位精度为0.01cm,具有较高的可靠性和准确性,低成本,稳定性好。     

多元统计分析在塔里木瓦吉里塔格钒钛磁铁矿床多元素相关性及成矿预测研究中的应用

塔里木巴楚县瓦吉里塔格地区出露有与塔里木早二叠世大火成岩省的形成密切相关的大型钒钛磁铁矿床. 基于多元统计分析对该矿区露头和大量钻孔岩心样品中Fe-Ti-V元素和部分主量元素数据开展了元素地球化学相关性研究. 采用SPSS软件对大量数据进行相关分析和回归分析,计算各元素间的相关系数,Fe、Ti、V 3种元素的相关性分析结果表明： 矿床中Fe、Ti和V之间均呈正相关, 成矿元素与造岩元素之间存在负相关关系;建立伴生钒元素与铁和钛元素之间关系的回归方程V=-4.984+0.360 Fe+0.984Ti,由Fe和Ti元素质量分数可以估算伴生组分V的质量分数.利用Matlab软件的可视化功能,绘制了Fe-Ti-V元素质量分数的三维立体图,建立空间模型,发现Fe₂O_3T、TiO₂和V₂O₅品位较高的位置相对一致,均主要分布于研究区北部中间一带,富集在辉石岩中. 该空间模型的建立有助于识别矿体和非矿体的分布范围和富集趋势,并进行成矿预测. 此项研究对钒元素含量的精确估算和矿藏勘探有一定的指导意义.     

Ultrasound line-by-line scanning method of spatial–temporal active cavitation mapping for high-intensity focused ultrasound

This paper presented an ultrasound line-by-line scanning method of spatial–temporal active cavitation mapping applicable in a liquid or liquid filled tissue cavities exposed by high-intensity focused ultrasound (HIFU). Scattered signals from cavitation bubbles were obtained in a scan line immediately after one HIFU exposure, and then there was a waiting time of 2 s long enough to make the liquid back to the original state. As this pattern extended, an image was built up by sequentially measuring a series of such lines. The acquisition of the beamformed radiofrequency (RF) signals for a scan line was synchronized with HIFU exposure. The duration of HIFU exposure, as well as the delay of the interrogating pulse relative to the moment while HIFU was turned off, could vary from microseconds to seconds. The feasibility of this method was demonstrated in tap-water and a tap-water filled cavity in the tissue-mimicking gelatin–agar phantom as capable of observing temporal evolutions of cavitation bubble cloud with temporal resolution of several microseconds, lateral and axial resolution of 0.50 mm and 0.29 mm respectively. The dissolution process of cavitation bubble cloud and spatial distribution affected by cavitation previously generated were also investigated. Although the application is limited by the requirement for a gassy fluid (e.g. tap water, etc.) that allows replenishment of nuclei between HIFU exposures, the technique may be a useful tool in spatial–temporal cavitation mapping for HIFU with high precision and resolution, providing a reference for clinical therapy.     

67.9W高功率全光纤白光超连续谱激光器

利用自主研发的全光纤被动锁模激光器以及高功率光纤模场匹配器,将145 W的皮秒脉冲耦合进国产光子晶体光纤,实现了67.9 W的高功率全光纤结构白光超连续谱输出,光谱范围为500~1700nm,10dB光谱宽度大于1000nm(泵浦波长除外)。整个激光器系统的光-光(半导体泵浦源输出激光-超连续谱输出激光)转化效率达到33.8%。     

Analysis of capacity and outage probability for intersatellite optical communications in the presence of random pointing jitter

This work is motivated by the need to achieve the Shannon channel capacity for intersatellite optical communication with intensity modulation and direct detection. In this paper, we investigate the tradeoff between the channel capacity and the outage probability in the presence of random pointing jitter for intersatellite optical links. First, we derive an analytical expression of the outage probability in the absence of bias error, and then the bias error is taken into account. By minimizing the outage probability, we obtain analytically the optimum design of the beam half-width divergence angle $ w_0^{\text{opt}} $ for a given channel code rate. Furthermore, we discuss the tradeoff between the outage probability and the channel capacity and illustrate the results by adopting $ w_0^{\text{opt}} $ in the presence of random pointing jitter. The results obtained are useful for the parametric-estimation optimization of intersatellite optical communication systems.