高温超导滤波器应用在移动通信基站中的优势

由于高温超导滤波器应用到移动基站前端可以提高基站的性能,因此受到了广泛的重视。该文介绍了高温超导滤波器的发展状况,研究了高温超导薄膜材料的微波性能。与普通的金属滤波器相比,高温超导滤波器在移动通信基站的应用中显示出了它的优越性能:其具有接近于理想的频率响应特性;能很好地抑制带外信号的干扰;可以节约频率资源、增加基站覆盖面积和通话容量;还能够提高通话质量和降低功率辐射等。文中还进一步介绍了国内外高温超导滤波器在移动通信基站中的应用情况。     

Nonabsorbable Iron(III) binding polymers: Synthesis and evaluation of the chelating properties

Iron is a key micronutrient essential for many biological events. While iron deficiency can lead to anemia, supplementation with oral iron often ends up with enteral iron overload, a critical gastrointestinal (GI) burden linked to the increased risk of dysbiosis, infections and often associated with colorectal cancer. Iron chelation therapy is clinically used to reduce pathological systemic iron overload by established low molecular weight iron chelators. As drawbacks, these drugs present low pharmacokinetic profiles and several toxicities, leading to relatively high rates of adverse effects. To overcome these issues, the prevention of iron accumulation in the GI tract by non-absorbable iron binding polymers could represent an alternative still underexploited approach. Here, we present the development of a series of insoluble polymeric Fe(III) chelators. These innovative compounds have been obtained by the conjugation of 3-hydroxypyridin-4-one Fe(III) chelating moiety with branched Polyethyleneimine (PEI) and Carboxymethyl cellulose (CMC). In vitro binding studies indicated that the Fe(III) chelating capacity depends on the nature of the polymer. In particular, PEI derivatives possess higher selectivity toward Fe(III) in simulated intestinal fluid preserving the integrity of intestinal enterocytes, representing thus promising compounds in the development of iron chelators.     

Context matters: The impact of product type,emotional attachment and information overload on choice quality

We show that contextual variables in a Multiple Criteria Decision Making task influence choice quality. Based on an experiment we investigate the effects of product type, emotional attachment, and the amount and structure of information provided. We measured choice quality with nondominance, which is a desirable property of good choices. Regarding the product type effect, we distinguish between hedonic products that primarily are desirable due to affect, and utilitarian products, which are desirable because they are useful. When subjects with high emotional attachment make choices with hedonic products, they make fewer dominated choices than with utilitarian products. Further, we show that information overload is a relevant phenomenon in MCDM experiments. However, what matters is the quality of information, not just the quantity. When we add information that does not change the dominance relations between products, choice quality is not degraded.     

Influence on Emulsification in Binary Flooding of Oil Displacement Effect

As one of the important mechanisms of EOR for SP binary flooding, emulsification attracts much attention of researchers. But there have not yet unified methods or clear understandings of evaluation of the emulsion function on flooding system and emulsification's impact on enhanced oil recovery. A comprehensive evaluation method of emulsifying properties is established in this paper for the first time. It characterizes the emulsifying properties of different flooding system by using the emulsifying integrated index, and examines the corresponding core flooding results of different emulsifying properties. Results of Berea core test show that the flooding system runs better with a higher emulsifying composite index in cores whose permeability is 300 ～ 400 mD. When emulsifying integrated index increases from 23.9% to 80.2%, the corresponding oil displacement efficiency reaches 12%. When emulsifying integrated index is under the medium level of 50% or less, the SP flooding system efficiency increases rapidly with the index changes, then increases slowly. The influencing rule of emulsification of SP binary flooding is obtained in this paper, which is important to optimize the formulation of SP binary flooding system, provide an important basis and technical support for the design of field experiments and SP flooding promotion.     

Application of capability indices and control charts in the analytical method control strategy

In this study, we assessed the usefulness of control charts in combination with the process capability indices, C _pm and C _pk, in the control strategy of an analytical method. The traditional X‐chart and moving range chart were used to monitor the analytical method over a 2‐year period. The results confirmed that the analytical method is in‐control and stable. Different criteria were used to establish the specifications limits (i.e. analyst requirements) for fixed method performance (i.e. method requirements). If the specification limits and control limits are equal in breadth, the method can be considered “capable” (C _pm = 1), but it does not satisfy the minimum method capability requirements proposed by Pearn and Shu (2003). Similar results were obtained using the C _pk index. The method capability was also assessed as a function of method performance for fixed analyst requirements. The results indicate that the method does not meet the requirements of the analytical target approach. A real‐example data of a SEC with light‐scattering detection method was used as a model whereas previously published data were used to illustrate the applicability of the proposed approach.     

Design and fabrication of liquid crystal-based lenses

ABSTRACT

Liquid crystal (LC)-based lenses are promising for a wide range of applications from optical communications and signal processing to three-dimensional displays. Among a variety of the LC-based lenses, several classes including the Fresnel type and the lenticular type are comprehensively reviewed from the standpoints of the basic concepts and the device architectures. The underlying mechanisms for the focusing effect and the tuning capability inherent to the lens configuration are described. Recent progress on the LC-based lenses for reconfigurable optical processing and autostereoscopic displays is also presented. The lens architecture combined with the intrinsic anisotropy of the LC provides a versatile platform to build up high-performance LC-based lenses with the tuning capability.     

基于裂纹闭合效应的高载迟滞预测模型修正

裂纹闭合效应通常是导致I 型裂纹扩展在高载作用下发生迟滞效应的主要因素之一．本文采用汽车薄板QSTE340TM 材料，针对不同应力比，高载比条件下疲劳裂纹扩展行为进行了实验研究．论文通过断面分析，针对各参数对裂纹闭合效应的具体影响进行了分析讨论，认为裂纹作用区域随裂纹扩展而动态变化，从而提出了一种对有效应力强度因子幅的修正方法．通过在原有模型中引入幂函数形式的动态变量α，表征裂纹闭合效应的作用比例随裂纹长度的动态变化，取得了较好的效果．     

新型Li_4Ti_5O_(12)@石墨烯的微波辅助合成及电化学性能研究

将钛酸四丁酯和氧化石墨超声分散于叔丁醇,微波辐射下加入醋酸锂溶液制备尖晶石Li4Ti5O12(LTO)前驱体/氧化石墨烯。一方面,微波作用促进了钛酸四丁酯水解,前驱体的形成能在15 min内完成。另一方面,叔丁醇的"软模板"限域作用导致形成粒子极小且形貌单一的LTO前驱体。同时,细小的LTO前驱体粒子通过二次团聚将氧化石墨烯纳米片完全包埋。最后,LTO前驱体/氧化石墨烯在800℃下煅烧8 h得到尖晶石LTO@石墨烯(LTO@G)。研究表明,LTO@G晶体尺寸在0.2~1.5μm之间,其振实密度达到1.7 g·cm-3。石墨烯位于晶体内部,并显著提高了材料的电子传导性。LTO@G的电导率为1.84×10-3 S·m-1,远高于纯相LTO(1.1×10-7 S·m-1)。1C和4C下,LTO@G首次充放电容量分别是170.1和97.5 m Ah·g-1。可见,LTO@G具有高倍率性能和振实密度,可广泛应用于各种商品锂离子电池。