陆域大地电磁基础网规划与展望

阵列式大地电磁测深是区域地球物理调查的重点发展方向之一,对标国外先进水平和国家社会的基础性需求,中国阵列式大地电磁测深工作程度依然较低,缺乏整体规划,开展全国性观测计划亟需提上日程。系统总结了当前区域地球物理学的发展趋势及国内外大地电磁网建设现状,提出了合作共建陆域多层级大地电磁基础网和大数据中心的顶层设计和规划布局,并对中国大地电磁基础网未来的重点发展方向进行了展望和思考。相关工作的顺利开展将为中国的区域地球物理调查拓展一项新属性参数,推动构建物性地球、结构地球和地球物理场四维模型,进而变革区域地球物理研究范式和工作模式,支撑中国深地探测走向世界前列。

Evaluation and Analysis for Survey of Tea Production Quality Safety Management and Control

[Objectives]This study was conducted to investigate and evaluate the quality safety of tea production in China.[Methods]With the production of famous and high-quality green tea in the western Sichuan tea areas as the investigation object,the practice survey and comprehensive evaluation analysis method were adopted to conduct research on tea production quality safety management and control,and a comprehensive evaluation was carried out in combination with the survey.[Results]Statistical analysis and scoring were carried out according to relevant indices,and the current situation of tea production quality safety was comprehensively evaluated.Four hazards were found,including pesticide residues,heavy metal residues,harmful microorganisms and non-tea impurities,and improvement measures were proposed.[Conclusions]This study provides a theoretical reference for improving the quality safety of tea production in China.

应用样条拟合与插值法抑制航空电磁运动噪声

呈现低频特性的运动感应噪声源于电磁感应接收线圈在地磁场中的运动变化,在固定翼时间域航空电磁测量数据中,其幅值往往达到有用信号的成百上千倍,原始数据中运动噪声的精确估计是目前时间域航空电磁法数据去噪技术的重点研究方向。针对电磁感应接收信号的特点,首先应用三次样条拟合法在截取的半周期晚期信号中压制高频干扰,提取低频运动噪声信息,然后用一维样条插值法估计连续的全周期运动噪声,最后从观测信号中减去估计信号,从而实现对运动噪声的抑制。对模拟数据和实测数据的应用研究结果表明,样条拟合与插值法对低于发射基频运动噪声的抑制效果显著,选用较小的均衡参数可以提高噪声压制能力,选用较大的延迟取样点,可以减轻对晚期有用信号的损伤,提高深部探测能力。

航空电磁时间域数据工频干扰研究与去除

时间域航空电磁系统在飞行作业过程中,信号受人文噪声中的高压输电线影响,导致测得的响应中含有工频干扰信息而不能真实地反映地下介质分布情况,因此本文开展了工频干扰噪声去除研究,提出一种可直接在时间域中对数据进行处理的梳状滤波器,该滤波器的提出不仅节省了时—频和频—时转换的时间,也避免了繁琐的转换步骤,降低了转换过程中可能出现误差的风险。利用梳状滤波器的关键点是通过理想阻带来抑制工频频率信号及其k次谐波,达到对工频干扰压制的目的。本文不仅研究了IIR型和FIR型梳状滤波器,同时对比了单一陷波滤波器对工频干扰的去除效果,期望通过该研究可以为时间域航空电磁数据处理提供一种高效的工频干扰去除手段。

航空地球物理装备研发与技术发展回顾

21世纪以来,我国航空地球物理从理论方法技术研究到装备研发快速发展,这里简要回顾了近15年中国地质科学院地球物理地球化学勘查研究所(物化探所)航空地球物理装备研发和方法技术研究历程。为满足国家战略及市场需求,尤其“十一五”以来,时间域航空电磁测量系统、无人机航空物探综合测量系统、直升机航空物探(磁/放)综合测量系统等大型航空物探装备的研发和应用取得了突破性进展,航空物探资料的处理与解释工作得到了加强,在基础地质调查、水文地质调查油气及矿产资源勘查等领域成果显著。为满足国家在地下水资源勘查、生态环境与灾害监测、战略性矿产勘查等领域的需求,物化探所将进一步加强航空地球物理装备研发及方法技术研究工作,促进各类系统的实用性、经济性、稳定性,扩展应用领域,广泛服务于社会、生态、民生、经济、军事等领域。

“十一五”以来勘查地球物理发展回顾与展望

随着现代先进的计算机技术、传感技术以及新材料、新工艺等科学技术的进步,我国勘查地球物理工作得到了快速发展。近15年来,物化探所在地球物理仪器装备研发、方法技术创新,服务国家需求等方面取得了显著成果:构建了“航空-地面-地下”地球物理立体勘查方法技术体系,自主研发了固定翼时间域航空电磁测量系统、无人机航磁测量系统,大功率多功能三维电磁测量系统、高精度磁传感器和高温超导磁强计,创新了全区多源电磁测量方法。同时,在固体矿产和油气资源勘查,页岩气、陆域天然气水合物、干热岩及地热等清洁能源调查,基础地质调查、工程环境调查监测等方面取得了一系列新进展,建立了地球物理勘查技术标准体系和信息化平台。

油气地球物理勘探回顾与展望

地球物理勘探是获取地下油气资源信息的重要手段和核心技术,是油气勘探开发部署决策的重要依据。聚焦国家关于能源资源安全保障的决策部署,近二十年来,在国家科技专项、地质调查项目等的支持下,物化探所先后在青藏高原、东北、长江下游、柴达木等地区开展了一系列油气、页岩气地球物理勘查工作,在构建重要盆地地层和构造格架、油气资源评价和有利区优选等方面取得重要进展,支撑服务了多口地质调查井井位优选,在重要断裂的位置和空间展布、重要盆地的形成演化、沿江对冲带空间位置、郯庐断裂是否南延等基础地质问题研究方面取得新认识,形成了青藏高原、火山岩覆盖区、双复杂区等油气地球物理勘探关键技术。通过总结近二十年的油气地球物理勘探工作,提出了物化探所今后油气地球物理工作的发展趋势和主要研究方向,强调应重点探索新领域、新类型、新深度、老区新层系油气勘探潜力,攻关重磁电震联合反演等关键地球物理勘探技术,致力于构建复杂构造带油气地球物理探测体系。

Role of Notch signaling pathway in gastric cancer: A meta-analysis of the literature

AIM: To perform a meta-analysis to quantitatively summarize the evidence for the association between the Notch signaling pathway and gastric cancer ( GC). METHODS: An electronic search of the MEDLINE, EMBASE and Chinese National Knowledge Infrastructure, which contain articles published from 1966 onwards, was conducted to select studies for this meta-analysis. RESULTS: Fifteen studies with a total of 1547 gastric cancer cases and 450 controls were included in this meta-analysis. Overall, the expression of Notch1, Notch2, Delta-like 4 and Hes1 was significantly higher in tumor tissues of GC compared to normal tissues. Specifically, stratified analyses showed that significantly increased expression of Notch1 was associated with non-cardia location, > 5 cm size, diffuse type, positive lymphovascular invasion and distal metastasis. Statistically significant higher expression of Notch3 was found in diffuse type GC. Jagged1 was also significantly over-expressed in diffuse type and poor differentiation type of GC. DLL4 was significantly over-expressed in advanced T stage, N stage and TNM stage in GC patients. However, the stratified analysis showed that there was no statistically significant difference in Hes1 expression between different subgroups. Sporadic reports showed that Notch1 and Jagged1 were independent poor prognostic predictors in GC. CONCLUSION: The Notch signaling pathway plays an important role in tumor progression of gastric cancer. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.

Hierarchical sulfur and nitrogen co-doped carbon nanocages as efficient bifunctional oxygen electrocatalysts for rechargeable Zn-air battery

Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hierarchical sulfur and nitrogen co-doped carbon nanocages(hSNCNC) as a promising bifunctional oxygen electrocatalyst by an in-situ MgO template method with pyridine and thiophene as the mixed precursor. The as-prepared h SNCNC exhibits a positive half-wave potential of 0.792 V(vs. reversible hydrogen electrode, RHE) for ORR, and a low operating potential of 1.640 V at a 10 mA cm-2 current density for OER. The reversible oxygen electrode index is 0.847 V, far superior to commercial Pt/C and IrO2,which reaches the top level of the reported bifunctional catalysts. Consequently, the hSNCNC as air cathodes in an assembled Zn-air battery features low charge/discharge overpotential and long lifetime. The remarkable properties arises from the introduced multiple heteroatom dopants and stable 3D hierarchical structure with multi-scale pores, which provides the abundant uniform high-active S and N species and efficient charge transfer as well as mass transportation. These results demonstrate the potential strategy in developing suitable carbon-based bi-/multi-functional catalysts to enable the next generation of the rechargeable metal-air batteries.

Application of ionic liquids in CO_(2)capture and electrochemical reduction:A review

As a new type of green solvent with non-volatility,high thermal stability,high conductivity and various adjustable properties,ionic liquid(IL)has been widely used in the capture and electrochemical reduction of carbon dioxide(CO_(2)).To date,many studies have been made to investigate CO_(2)capture by using different types of ILs and CO_(2)electrochemical reduction(CO_(2)ER)with ILs as either electrolyte or other catalytic active components.Some structure-activity relationships between the structure and adsorption or catalytic properties of ILs have been found.Herein,the absorption performances and mechanisms of conventional ILs,amino-functionalized ILs,non-amino functionalized ILs and supported ILs for CO_(2)capture,as well as the performances and action mechanisms of ILs as the electrolyte,electrolyte additive,and/or electrode modifier in the process of CO_(2)ER are summarized.Many researches indicate that the unique interaction between the anion or cation of IL and CO_(2)has a significant contribution to promote the absorption and conversion of CO_(2).However,the ILs used for CO_(2)capture and electrochemical reduction should be further explored.Especially,a more in-depth investigation of the adsorption and catalytic mechanisms with the help of quantum chemical calculation,molecular simulation,and in situ characterization techniques is necessary.It is expected to design and develop more efficient ILs used for CO_(2)capture and conversion on a large scale.

Power Distribution Strategy Considering Active Power Loss for DFIGs Wind Farm

With the development of concentrated wind power areas, new energy’s dispatching problems are more prominent with its fast expansion. However, we can maximize the utilization of wind power under power curtailment conditions by optimal wind power dispatching. The paper studies on the basic theories of wind power turbines, and analyses the power’s control and output characteristics of wind turbine, which analyses the double-fed inductor generator’s excellent decoupling control of power and its excellent reactive power output capability. By studying the characteristics of wind power output, this paper provides a strategy for optimal dispatch in wind power generation. The calculation results show that the total active and reactive power output of the wind farm match the request of dispatch center. And the total active loss and total reactive loss is the least in the meantime.

A Motion and Counting Based-Routing Algorithm for Delay Tolerant Network

Considering the characteristics of Vehicular Ad-hoc Network (VANET), we here propose a Delay-Tolerant Networks (DTN) routing algorithm called Motion and Counting Based-Spray and Seek Routing algorithm (MNCBSS). This algorithm is based upon Spray and Wait Router and describes the method of optimization and specific procedures of the algorithm. Whereafter we perform the simulation over several classic DTN routing algorithms and MNCBSS algorithm, compare the routing algorithms by sketching the statistics and then give the analysis of the different performance of each scheme and eventually demonstrate effectiveness and reliability of the MNCBSS algorithm.

Simulation of gas-solids heat transfer in cyclone pyrolyzer using CFD-DEM model

Fast heat transfer in the pyrolyzer can increase the yield of pyrolysis gas and tar,and improve the quality of tar.Compared with the downer pyrolyzer,the cyclone pyrolyzer can simultaneously achieve high solids holdup and violent turbulence,and correspondingly faster heat transfer.In this work,the heat transfer behavior in the cyclone pyrolyzer is specifically studied using the computational fluid dynamics-discrete element method.The simulation results reveal that the gas-solids heat convection contributes mainly to the heat transfer process,and the heat radiation and conduction are relatively small and almost negligible,respectively.Compared with the downer pyrolyzer under the same operating conditions,the heating rate is significantly increased in the cyclone pyrolyzer.By analyzing the flow characteristics in the cyclone pyrolyzer,it is found that the region of high convective heat transfer rate coincides with that of natural cyclone length.Additionally,the final coal temperature increases with the increase of gas velocity and exists a maximum value.These results can offer some qualitative understanding of the heat transfer behavior in the cyclone pyrolyzer.

Don先生

一、董先生。他戴着口罩,坐在你对面。“董先生您好,”你讲英文,“我是谭律师,艾米的朋友。”“谭律师您好,”他也用英文回答,“谢谢您过来,谢谢您做我的律师。”他穿一身灰色囚服,胸前绣着Correctional Facility of Derby County。该怎么翻译?德比郡惩教所?劳教所?教养所?或干脆就是德比郡监狱?你还是习惯把county译成县:在国内的县城长大,在这边的县城老去。

中国野球与美国官司

作为群体,中国人何其庞大。作为个体,中国人何其多样。在我看来,由多样而带来的参差多态,未必是幸福的本源,但肯定是写作的不二源泉。所以当笔落在稿纸上,中国人的个体让我激动。除了体量相当,中美两国在许多方面截然不同,甚至相反。当中国人来到这个迥异的环境,需要面对怎样的落差?这落差又会给我们彼此间的多样带来什么影响?我们是会被美国的环境同化成美国人,还是反倒活得更像中国人?

Construction of nitrogen-doped carbon cladding LiMn_(2)O_(4) film electrode with enhanced stability for electrochemically selective extraction of lithium ions

Reducing the dissolution of Mn from LiMn_(2)O_(4)(LMO)and enhancing the stability of film electrodes are critical and challenging for Li+ions selective extraction via electrochemically switched ion exchange technology.In this work,we prepared a nitrogen-doped carbon cladding LMO(C-N@LMO)by polymerization of polypyrrole and high-temperature annealing in the N2 gas to achieve the above purpose.The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode.The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42%compared to the LMO film electrode after 10 cycles.The cladding layer not only acted as a protective layer but also functioned as a conductive shell,accelerating the migration rate of Li+ions.The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li+ions,which was 33%less compared to the pure LMO film electrode.Meanwhile,the C-N@LMO film electrode retained evident selectivity toward Li+ions,and the separation factor was 118.38 for Li+toward Mg2+in simulated brine.Therefore,the C-N@LMO film electrode would be a promising candidate for the recovery of Li+ions from salt lakes.

Coercivity enhancement of hot-deformed Nd-Fe-B magnets with Pr-Cu alloy addition

Effects of low-melting Pr-Cu alloy addition on the microstructure and magnetic properties of the hot-deformation Nd-Fe-B magnets were investigated.A small amount of Pr-Cu addition enhances the coercivity of the hot-deformation Nd-Fe-B magnets obviously.The coercivity of the hotdeformation Nd-Fe-B magnets with 4.0 wt%Pr_(85)Cu_(15)addition increases to 1271 kA·m^(-1),75.69%higher than that of Pr-Cu-free magnet(723 kA·m^(-1)),and then decreases with5 wt%Pr_(85)Cu_(15)addition.It is observed that there a uniform RE-rich phase is formed wrapping the Nd2Fe14B main phase in the sample with 4.0%Pr_(85)Cu_(15)addition by scanning electron microscopy(SEM),which promotes the coercivity.The angular dependence of coercivity for the hot-deformation Nd-Fe-B magnets indicates that the coercivity mechanism is nucleation combined with domain wall pinning.The domain wall pinning is weakened,while the nucleation is enhanced after Pr-Cu addition.Theremanence,intrinsic coercivity,and maximum magnetic energy product of the original Nd-Fe-B magnet are 1.45 T,723 kA·m^(-1),and 419.8 kJ·m^(-3),respectively,and those of the sample with 4.0%Pr_(85)Cu_(15)alloy addition are 1.30 T,1271 kA·m^(-1),and 330.0 kJ·m^(-3),respectively.

电控离子(交换)膜分离技术——从ESIX到ESIPM

电控离子膜(Electrically Switched Ion Membrane,ESIM)分离是近年来发展起来的一种新型离子选择性高效分离技术,已被用于多种金属阳离子及阴离子的选择性分离与回收。电控膜分离源于电控离子交换(Electrically Switched Ion Exchange,ESIX)技术,其高效运行依赖于具有离子交换功能的电活性材料(Electroactive Ion Exchange Material,EIXM)。EIXM既能传递电子又能传递离子,通过调节其氧化/还原电位可以控制离子的可逆置入/释放,同时实现目标离子的高效分离和EIXM的再生,因而不产生二次污染。本文从EIXM简介、结构设计与可控合成、各种电控离子选择性分离机制的研究进展以及新型ESIX-ESIM膜组件开发和应用几个方面,分析总结了从最初的ESIX技术到基于ESIX原理的电控离子选择渗透膜(Electrically Switched Ion Permselective Membrane,ESIPM)分离的发展历程。展望未来ESIM分离技术,应针对目标离子的选择性分离要求,设计合成新型结构ESIM材料和研发相关膜组件系统,可望最终实现ESIM技术的工业应用。

Adjustable-free and movable Nd:YVO_(4) thin disk laser based on the telecentric cat's eye cavity

In this paper, we propose and demonstrate an adjustable-free and movable Nd:YVO_(4)thin disk laser based on the telecentric cat’s eye cavity. We design a V-shaped laser cavity containing two reflectors with Nd:YVO_(4)thin disks as the gain medium.The experimental results from the traditional plane-plane cavity, plane-telecentric cat’s eye cavity, and double telecentric cat’s eye cavity are compared. They show that plane-telecentric cat’s eye cavity laser can keep operating at the adjustablefree range of -6° to +6°, which is up to 60 times better than that of traditional plane-plane cavity. In the double telecentric cat’s eye case, the adjustable-free range is improved to-13° to +13°. Additionally, in the case of the double telecentric cat’s eye cavity, the output telecentric cat’s eye can achieve free movement within the horizontal range of ±20 mm.

High-power operation of double-pass pumped Nd:YVO4 thin disk laser

A simple,compact,double-pass pumped Nd:YVO4 thin disk laser is demonstrated.Its continuous-wave performance with different Nd doping concentrations and thicknesses is investigated experimentally.The maximum output power of 17.7 W is achieved by employing a 0.5 at.%doped sample,corresponding to an optical-to-optical efficiency of 46% with respect to the absorbed pump power.In addition,a numerical analysis and an experimental study of the temperature distribution,and thermal lens effect of the Nd:YVO4 thin disk,are presented considering the influence of the energy transfer upconversion effect and the temperature dependence of the thermal conductivity tensor.The simulated results are in good agreement with the experimental results.