碎屑岩中长石蚀变形成次生孔隙的试验研究

次生孔隙发育带是深层寻找有利油气勘探目标区的基础,酸性地层水是含油气盆地内部物质迁移和能量交换的主要介质。利用含乙酸溶液,模拟地层水,对济阳坳陷的长石砂岩进行高温高压条件下溶蚀试验,使用扫描电镜、X-衍射分析设备对实验产物进行对比检测。实验证明：（1）高温高压条件下乙酸对长石矿物有很强的溶蚀作用。（2）斜长石比钾长石更容易遭到溶蚀。结合济阳坳陷深层勘探实际,认为深层长石溶蚀耗水作用导致岩石孔隙度变大,形成次生孔隙,从而改善深层储层物性。同时长石溶蚀耗水作用是油气运移成藏活动一种驱动力。     

A novel CMOS charge-pump circuit with current mode control 110 mA at 2.7 V for telecommunication systems

This paper presents a novel organization of switch capacitor charge pump circuits based on voltage doubler structures. Each voltage doubler takes a DC input and outputs a doubled DC voltage. By cascading voltage doublers the output voltage increases up to 2 times. A two-phase voltage doubler and a multiphase voltage doubler structures are discussed and design considerations are presented. A simulator working in the Q-V realm was used for simplified circuit level simulation. In order to evaluate the power delivered by a charge pump, a resistive load is attached to the output of the charge pump and an equivalent capacitance is evaluated. To avoid the short circuit during switching, a clock pair generator is used to achieve multi-phase non-overlapping clock pairs. This paper also identifies optimum loading conditions for different configurations of the charge pumps. The proposed charge-pump circuit is designed and simulated by SPICE with TSMC 0.35-μm CMOS technology and operates with a 2.7 to 3.6 V supply voltage. It has an area of 0.4 mm2; it was designed with a frequency regulation of 1 MHz and internal current mode to reduce power consumption.     

一种低功耗64倍降采样多级数字抽取滤波器设计

经典多级结构的数字抽取滤波器占用系统大量的功耗与面积资源,文章设计的改进型64倍降采样数字抽取滤波器采用由级联积分梳状滤波器、补偿FIR滤波器和半带滤波器组成,在保持Σ-ΔADC转换精度的约束下,实现了最大程度降低系统功耗与面积的设计目标。在多级级联积分梳状(CIC)滤波器的设计中,充分运用置换原则以优化各级级数并采用非递归结构实现方式,同时将多相结构运用到补偿滤波器与半带滤波器中,获得电路功耗与面积的明显降低。将Σ-Δ调制器输出信号作为测试激励,通过Matlab系统仿真、FPGA验证与FFT信号分析,得到的输出数据信噪比达到15bit有效位数精度,且系统速度满足要求。     

Evolution of dispersive liquid–liquid microextraction method

Dispersive liquid–liquid microextraction (DLLME) has become a very popular environmentally benign sample-preparation technique, because it is fast, inexpensive, easy to operate with a high enrichment factor and consumes low volume of organic solvent. DLLME is a modified solvent extraction method in which acceptor-to-donor phase ratio is greatly reduced compared with other methods. In this review, in order to encourage further development of DLLME, its combination with different analytical techniques such as gas chromatography (GC), high-performance liquid chromatography (HPLC), inductively coupled plasma-optical emission spectrometry (ICP-OES) and electrothermal atomic absorption spectrometry (ET AAS) will be discussed. Also, its applications in conjunction with different extraction techniques such as solid-phase extraction (SPE), solidification of floating organic drop (SFO) and supercritical fluid extraction (SFE) are summarized. This review focuses on the extra steps in sample preparation for application of DLLME in different matrixes such as food, biological fluids and solid samples. Further, the recent developments in DLLME are presented. DLLME does have some limitations, which will also be discussed in detail. Finally, an outlook on the future of the technique will be given.     

基于无人机无线能量传输的边缘计算系统能耗优化方法研究

无线能量传输(WPT)和移动边缘计算(MEC)可以为无线设备提供能量供应和任务计算,有效提高设备的能量效率。该文提出一种基于无人机无线能量传输的边缘计算系统能耗优化方法,在所提方法中,通过联合优化能量收集(EH)时间、用户发射功率和卸载决策,最小化系统总能耗。利用块坐标下降法(BCD),将优化问题分解为两个子问题,通过交替优化来获得最优能量收集时间、用户发射功率和卸载决策。仿真结果表明,该文提出的系统能耗优化方法优于其他基准方案,并且系统所需能量可以显著减少。     

基于PS021微小电容低功耗测量电路的设计

提出一种微小电容低功耗测量电路的设计方案。该电路具有功耗低、体积小、抗干扰性强、分辨力高、刷新率高的特点。阐述了测量电路的基本原理、具体实现和各模块功能,并且通过测量0~5 pF范围的动态电容验证了电路的性能。提高了微小电容的测量精度,具有良好的应用前景。     

投资性消费:一个不可忽视的现象

从近些年来我国居民消费不足但住房消费明显增加的事实引出了投资性消费的概念,并运用理论模型揭示了投资性消费兴起的原因.分析表明,投资性消费是我国近年来居民消费率持续走低的一个重要原因.投资性消费产生于人们规避损失、追逐利益的内在冲动,在商品价格显著上涨、货币利率较低、通货膨胀预期强烈之时,投资性消费的需求弹性较大.住房投资性消费具有较强的不确定性和风险性,在一定程度上放大了真实的需求.由于房地产涉及的行业广泛,因而也加大了宏观经济的风险性及对经济准确判断的难度.本文运用我国住房领域相关数据,对居民消费率进行了修正,揭示了住房投资消费削弱居民一般商品消费的事实.认为应及时遏制房地产价格过快上涨以及住房投资性消费过度增加的状况,避免其对经济的损害.     

Endogenous Fluctuations in Two-Sector Models: Role of Preferences

We consider a discrete-time two-sector CES (constant elasticity of substitution) economy with sector specific external effects and nonlinear preferences. Our goal is to examine carefully the influence of the utility curvature on the occurrence of multiple equilibria. We show that local indeterminacy depends on an interplay between factor substitutability and the elasticity of intertemporal substitution in consumption. Moreover, considering that, when the external effects are set equal to zero, we get a two-sector optimal growth model, we study also the role of the utility curvature on the occurrence of competitive equilibrium cycles. We show that persistent endogenous fluctuations and macroeconomic volatility require a strong enough elasticity of intertemporal substitution in consumption. We thank two anonymous referees for helpful comments and suggestions. External effects are feedbacks from the other agents in the economy who face also identical maximizing problems. See Benhabib and Farmer (Ref. 1) for a survey. Global indeterminacy based on a finite number of equilibria is associated with the existence of thresholds and multiple steady states. See Deissenberg, Feichtinger, Semmler, and Wirl (Ref. 2).     

一种低功耗原边反馈AC/DC转换器

低待机功耗、高效率的绿色电源已成为未来电源技术发展的方向,国际上已经正式提出六级能效标准。提出了一种采用常规工艺实现的原边反馈AC/DC转换器电路,解决了传统原边反馈AC/DC转换器元器件多、待机功耗大以及用高压特殊工艺实现低待机功耗的成本昂贵等问题。该原边反馈AC/DC转换器能够满足六级能效标准。     

一种高电源抑制比低温漂系数带隙基准电路

设计了一种用于DC-DC开关电源芯片的高电源抑制比、低温漂系数带隙基准电路。基于0.5μm BCD工艺,仿真结果表明,在不显著增加电路面积损耗的前提下,该电路的电源抑制比在低频下接近110dB,100kHz时约为50dB,1MHz时约为40dB;通过高温时的高阶温度补偿,0℃~100℃范围内的温度系数低于1.0×10-5/℃。此外,电流温度补偿的运用可有效地减小电流温度系数,从而使得芯片中的振荡器的频率输出更加稳定。