Lowering customer’s switching cost using B2B services for telecommunication companies

A B2B transaction is a transaction between organizations. However, the ripple effects of a B2B transaction can reach the members of the organization and generate additional economic impact. Enterprise LTE (Long term evolution) is a newly introduced B2B service in the South Korean telecommunications market. While it provides secure and fast telecommunications services to businesses, it can also affect the employees’ utility in the business, since the service provider can provide a variety of additional services to employees who use the same telecommunications provider for their mobile devices. In this study, we empirically analyze how B2B and Enterprise LTE services affect consumer churn-in in the telecommunications market. We estimate consumer benefit based on the additional services provided after the introduction of the B2B service using conjoint analysis. We also estimate consumer switching cost for changing one’s mobile telecommunications service provider using contingent valuation method. By comparing these values, we analyze the switching probability of employees when B2B services are introduced at their workplace. The results show that in order to maximize revenue, considering the revenue gained from new subscribers and from fees for providing additional services, lowering service fees for additional services and maximizing market share are advisable.     

基于混合域的SAR回波快速算法

该文提出了一种基于混合域的SAR回波快速算法。该算法利用空变的系统传递函数参与计算,沿距离时域积分计算回波信号2维频谱,从而实现了回波信号的精确仿真。复杂度和性能分析表明,该算法不仅能够在保证较高相位精度情况下有效提高回波仿真速度,而且在2维时域内易于添加运动误差模型。最后针对点阵和面目标进行了仿真,验证了算法的有效性。     

Highly efficient photocatalytic treatment of mixed dyes wastewater via visible-light-driven AgI–Ag3PO4/MWCNTs

A high-performance photocatalyst of AgI–Ag₃PO₄/multi-walled carbon nanotubes (MWCNTs) was fabricated by chemical precipitation method using KI, K₂HPO₄ and AgNO₃ in the presence of MWCNTs. Its structure and physical properties were characterized by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD), UV–vis absorption spectra, X-ray photo-electron spectroscopy (XPS), photoluminescence spectra (PL) and photocurrent techniques. SEM, TEM and EDS analyses verified that AgI–Ag₃PO₄ is successfully loaded on MWCNTs. AgI–Ag₃PO₄/MWCNTs possess the absorption edge of red shift and small band gap energy, and could absorb more photons in the visible region. PL and photocurrent analyses illustrated that AgI–Ag₃PO₄/MWCNTs have the lowest emission peak intensity and the highest photoelectric current, compared with Ag₃PO₄, AgI and AgI–Ag₃PO₄. By using the photocatalytic degradation of mixed dyes wastewater of Orange II and ponceau 4R as a model reaction, the photocatalytic efficiencies of Ag₃PO₄, AgI, AgI–Ag₃PO₄ and AgI–Ag₃PO₄/MWCNTs were evaluated. The reaction results showed that AgI–Ag₃PO₄/MWCNTs have strong photocatalytic activity and excellent chemical stability in repeated and long-term applications. Therefore, the prepared AgI–Ag₃PO₄/MWCNTs could act as a high-performance catalyst for the photocatalytic degradation of mixed dyes wastewater and also suggested the promising applications.     

Simultaneous Static Testing of A/D and D/A Converters Using a Built‐in Structure

Static testing of analog‐to‐digital (A/D) and digital‐to‐analog (D/A) converters becomes more difficult when they are embedded in a system on chip. Built‐in self‐test (BIST) reduces the need for external support for testing. This paper proposes a new static BIST structure for testing both A/D and D/A converters. By sharing test circuitry, the proposed BIST reduces the hardware overhead. Furthermore, test time can also be reduced using the simultaneous test strategy of the proposed BIST. The proposed method can be applied in various A/D and D/A converter resolutions and analog signal swing ranges. Simulation results are presented to validate the proposed method by showing how linearity errors are detected in different situations.     

Ga_(1-x)Al_xP混晶的长波长光学声子谱

本文报道Ga_(1-x)Al_xP混晶的室温喇曼散射测试结果。所用的样品用液相外延方法生长在〈111〉晶向的GaP衬底上。混晶组分x值在0.16—0.65之间。实验结果表明,Ga_(1-x)Al_xP混晶的长波长光学声子谱呈现双模行为,具有类GaP和类AIP两个光学支。     

Non-interlayer and color stable WOLEDs with mixed host and incorporating a new orange phosphorescent iridium complex

In this work, we have synthesized a new phosphorescent iridium complex (Bppya)₂Ir(acac), as an orange dopant for organic light-emitting diodes (OLEDs). The device achieved an external quantum efficiency (EQE) of 22.4%, a current efficiency of 49.5 cd A⁻¹ and a power efficiency of 38.9 lm W⁻¹, which are among the highest values for orange OLEDs. Furthermore, color stable and high efficiency phosphorescent white OLED (WOLED) was demonstrated by utilizing a mixed-host in the emissive layers (EMLs) composed of a blue phosphor and the new orange phosphorescent emitter, as well as by avoiding the use of interlayers that commonly exist between different EMLs in WOLEDs. Our WOLED presented decent white emission with maximum efficiencies of 25.3 cd A⁻¹ and 12.6%. Furthermore, the 1931 Commission Internationale de l’Eclairage color coordinates exhibited extremely small variation of (0.3940 ± 0.0102, 0.4323 ± 0.0046) in a wide luminance range from 49 to 38,035 cd m⁻² when driving voltages increased from 4 V to 12 V. The root cause for this excellent color stability is the utilization of the mixed-host to obtain bipolar transport properties in EMLs as well as the eliminating of interlayer between different EMLs, which, on one hand, effectively broaden the exciton recombination zone; on the other hand, reduce the accumulation of triplet excitons at the emissive interface.     

蓝晶石和石英浮选行为的研究（待续）

通过表面张力测试、浮选试验和红外光谱的测定，研究了蓝晶石和石英在阴／阳离子混合表面活性剂系统中的浮选行为。研究结果说明了表面活性剂混合物引起的表面张力下降中的协同作用。在浮选系统中，由于这一协同作用的存在，油酸钠／十二胺的添加导致在很宽的ｐＨ范围内，浮选回收率提高。文中还分析了在阴／阳离子混合表面活性剂系统中捕收剂的吸附机理。     

某混合粗精矿铜铅分离选矿试验研究

混合粗精矿Cu品位8.51%、Pb品位15.23%;样品中黄铜矿、方铅矿包裹体较多,粒度较细,针对该样品性质,主要从浮选、重选角度进行铜铅分离试验研究,最终推荐粗精矿精选—铜铅分离(抑铅浮铜)—重选提高铅品位联合工艺流程;抑铅浮铜工艺采用自行设计的无氰、低铬、无污染组合抑制剂RBT-2,使铜、铅达到有效分离;最终可获得Cu品位21.50%、含Pb 4.57%、Cu回收率69.92%的铜精矿;Pb品位46.89%、含Cu 0.82%、Pb回收率55.39%的铅精矿。此流程中重选提高铅精矿品位工艺,使铅矿物得以富集,分离效果明显,获得了Pb品位大于40%的铅精矿。     

Improved extraction of oil from chickpea under ultrasound in a dynamic system

In this work, ultrasound-assisted dynamic extraction (UADE) is proposed. The dynamic approach allows go-and-backward circulation of solvent through the sample subjected to the action of ultrasound. The extraction efficiency of hexane, isopropanol, a hexane–isopropanol mixture as well as the comparison between static extraction and flow-through extraction with or without ultrasound were evaluated. The effects of ultrasonic power, extraction temperature, time and extractant flow rate on the yield of oil from chickpea were also investigated. Results showed that solvent type significantly influenced extraction efficiency, the combination of hexane and isopropanol obtained the highest oil yield. Dynamic system and ultrasonication dramatically enhanced the extraction of oil. Moreover, results indicated that 20 min was sufficient for UADE with lower cost to obtain higher extraction yields (10.45% and 2.06% higher) than those by 4 h conventional solvent extraction (CSE) and 30 min ultrasound-assisted extraction (UAE) for oil. Gas chromatography analysis of chickpea oil indicated that the oil was enriched with polyunsaturated fatty acids and few changes in fatty acid composition occurred in ultrasonicated oil.     

复合斜纹织物踏盘开口装置的设计与应用

论述了一上一下一上二下复合急斜纹织物踏盘开口装置的设计原理,制造及安装要点,并叙述了织机相应的技术改进措施及主要织造工艺参数的确定,为成功地开发生产仿真皮皮革基布创造了条件,为企业赢得了可观的经济效益,同时也为白织厂利用有梭织机生产特殊组织结构的产业用布开辟了一条新路。