Superconducting state in Ba_((1-x)) Sr_(x)Ni_(2)As_(2) near the quantum critical point

In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the mechanism is still under debate.Here,we report a detailed investigation of the superconducting properties near the QCP(x≈0.7) by utilizing scanning tunneling microscopy and spectroscopy.The temperature-dependent superconducting gap and magnetic vortex state were obtained and analyzed in the framework of the Bardeen-Cooper-Schrieffer model.The ideal isotropic s-wave superconducting gap excludes the long-speculated nematic fluctuations while preferring strong electron-phonon coupling as the mechanism for T_(C) enhancement near the QCP.The lower than expected gap ratio of Δ/(k_(B) T_(C)) is rooted in the fact that Ba_(1-x)Sr_(x)Ni_(2)As_(2) falls into the dirty limit with a serious pair breaking effect similar to the parent compound.

Performance Framework for Virtual Machine Migration in Cloud Computing

In the cloud environment,the transfer of data from one cloud server to another cloud server is called migration.Data can be delivered in various ways,from one data centre to another.This research aims to increase the migration performance of the virtual machine(VM)in the cloud environment.VMs allow cloud customers to store essential data and resources.However,server usage has grown dramatically due to the virtualization of computer systems,resulting in higher data centre power consumption,storage needs,and operating expenses.Multiple VMs on one data centre manage share resources like central processing unit(CPU)cache,network bandwidth,memory,and application bandwidth.Inmulti-cloud,VMmigration addresses the performance degradation due to cloud server configuration,unbalanced traffic load,resource load management,and fault situations during data transfer.VMmigration speed is influenced by the size of the VM,the dirty rate of the running application,and the latency ofmigration iterations.As a result,evaluating VM migration performance while considering all of these factors becomes a difficult task.Themain effort of this research is to assess migration problems on performance.The simulation results in Matlab show that if the VMsize grows,themigration time of VMs and the downtime can be impacted by three orders ofmagnitude.The dirty page rate decreases,themigration time and the downtime grow,and the latency time decreases as network bandwidth increases during the migration time and post-migration overhead calculation when the VMtransfer is completed.All the simulated cases of VMs migration were performed in a fuzzy inference system with performance graphs.

“软件需求分析”实验教学研究与实践

以金陵科技学院软件工程学院"软件需求分析"课程实验教学开展为例,探讨该课程教育教学模式。该课程实验环境为USDM平台系统的"需求/设计管理工具";实验内容从项目的准备、启动、展开、定型、评审五个环节开展,各环节采用CMMI标准管理,量化考核。学生自行组队,提出Dirty Example,角色轮换,团队协力工作,课中讨论、评审,课后复查、修正,高质量完成文档。并配套实验教材,直观指导,过程化实验环节,提出知识能力与职业能力一体培养的工程教育模式。

“软件需求分析”实验教学研究和实践

以金陵科技学院软件工程学院"软件需求分析"实验课程开展为例,研究探讨该课程教学模式。以USDM平台环境的"需求/设计管理工具"为实验平台,从软件需求项目准备、项目启动、项目展开、项目定型、项目评审五个环节开展实验,项目分组,角色轮换。学生自行提出Dirty Example,通过课后团队协力工作,课中讨论和评审,辅以及时的检查考核,并配套实验教材,细化各环节,提出融知识能力培养与职业能力培养于一体的工程教育教学模式。

Preparing for a “dirty bomb” attack: The optimum mix of medical countermeasure resources

Background: In radiological emergencies with radionuclide incorporation, decorporation treatment is particularly effective if started early. Treating all people potentially contaminated("urgent treatment") may require large antidote stockpiles. An efficacious way to reduce antidote requirements is by using radioactivity screening equipment. We analyzed the suitability of such equipment for triage purposes and determined the most efficient mix of screening units and antidote daily doses.Methods: The committed effective doses corresponding to activities within the detection limits of monitoring portals and mobile whole-body counters were used to assess their usefulness as triage tools. To determine the optimal resource mix, we departed from a large-scale scenario(60,000 victims) and based on purchase prices of antidotes and screening equipment in Germany, we calculated efficiencies of different combinations of medical countermeasure resources by data envelopment analysis. Cost-effectiveness was expressed as the costs per life year saved and compared to risk reduction opportunities in other sectors of society as well as the values of a statistical life.Results: Monitoring portals are adequate instruments for a sensitive triage after cesium-137 exposure with a high screening throughput. For the detection of americium-241 whole-body counters with a lower daily screening capacity per unit are needed. Assuming that 1% of the potentially contaminated patients actually need decorporation treatment, an efficient resource mix includes 6 monitoring portals and 25 mobile whole-body counters. The optimum mix depends on price discounts and in particular the fraction of victims actually needing treatment. The costeffectiveness of preparedness for a "dirty bomb" attack is less than for common health care, but costs for a life year saved are less than for many risk-reduction interventions in the environmental sector.Conclusion: To achieve economic efficiency a high daily screening capacity is of major importance to substantially decrease the required amount of antidote doses. Among the determinants of the number of equipment units needed, the fraction of the potentially contaminated victims that actually needs treatment is the most difficult to assess. Judging cost-effectiveness of the preparedness for "dirty bomb" attacks is an issue of principle that must be dealt with by political leaders.

Estimation of radiation-induced health hazards from a“dirty bomb”attack with radiocesium under different assault and rescue conditions

In the case of a terrorist attack by a“dirty bomb”,blast injuries,external irradiation and the incorporation of radioactivity are to be expected.Departing from information about the radiological attack scenario with cesium-137 in the U.S.National Scenario Planning Guide,we estimated the radiological doses absorbed.Similar calculations were performed for a smaller plume size and a detonation in a subway.For conditions as described in the U.S.scenario,the committed effective dose amounted to a maximum of 848 mSv,even for very unfavorable conditions.Red bone marrow equivalent doses are insufcient to induce acute radiation sickness(ARS).In the case of a smaller plume size,the ARS threshold may be exceeded in some cases.In a subway bombing,doses are much higher and the occurrence of ARS should be expected.The health hazards from a dirty bomb attack will depend on the location and the explosive device.The derived Haddon matrix indicates that preparing for such an event includes education of all the medical staff about radiation effects,the time lines of radiation damages and the treatment priorities.Further determinants of the outcome include rapid evacuation even from difficult locations,the availability of a specific triage tool to rapidly identify victims at risk for ARS,the availability of an antidote stockpile and dedicated hospital beds to treat seriously irradiated victims.

Direct observation of the scaling relation between density of states and pairing gap in a dirty superconductor

Theories and experiments on dirty superconductors are complex but important in terms of both theoretical fundamentals and practical applications.These activities are even more challenging when magnetic fields are present because the field distribution,electron density of states,and superconducting pairing potentials become nonuniform.Here,we present tunneling microspectroscopic experiments on NbC single crystals and demonstrate that NbC is a homogeneous dirty superconductor.When applying magnetic fields to the samples,we found that the zero-energy local density of states and the pairing energy gap followed the explicit scaling relation proposed by de Gennes for homogeneous dirty superconductors in high magnetic fields.More significantly,our experimental findings indicate that the validity of the scaling relation extends to magnetic field strengths far below the upper critical field,calling for a new nonperturbative understanding of this fundamental property in dirty superconductors.On the practical side,we used the observed scaling relation to derive a simple and straightforward experimental scheme for estimating the superconducting coherence length of a dirty superconductor in magnetic fields.

Performance of Block Diagonalization Broadcasting Scheme for Multiuser MIMO System Operating in Presence of Spatial Correlation and Mutual Coupling

In this paper, the capacity of a multiuser Multiple Input Multiple Output (MIMO) system employing the block diagonalization broadcasting scheme in presence of spatial correlation and mutual coupling is investigated. It is shown by computer simulations that, in general, the presence of spatial correlation decreases the capacity of a multiuser MIMO system. However, for some particular antenna element spacing mutual coupling decreases the spatial correlation rendering an increased capacity. The optimized diagonalization broadcasting technique with a two-stage power allocation scheme is proposed and verified. The presented simulations results confirm the advantage of the proposed broadcasting scheme.

增加表达委婉程度的英语动词

英语中有些动词,只要运用适当,可让表达更趋委婉,让对方更乐意接受。 1.建议对方别干某事时,可使用thank,allow,trouble(bother),suppose等。 I’ll thank you not to dirty my new bike. 求你别弄脏我的新自行车。句中的thank you not to…意思是“求你别……”,并不表示“感谢”,说话人或许有些不耐烦了,使用了thank可不致失礼。

绚丽多彩的颜色表达法

阅读英文原著,常见到对情景、人物的描写,如dirty greyclouds,pale yellow sunlight,vivid red lips和purplish browuface等。如果我们对颜色词的搭配关系不甚了解,就不能正确把握词义,还会影响对原文的理解,更不要说准确翻译了。自然界的颜色没有“肮脏”、“苍白”、“生动”的区别,却有浓、淡、明、暗之分,

与狗有关的习语

众所周知,西方人喜好养狗.因此英语中也就出现了许多与狗有关的习语.今年适逢又是中国人农历的狗年.在狗年谈狗更有一番情趣.Dog一词来自古英语里的docga、请看它的用法和习惯表述.1.指人(preceded by an adj)fellow or chap;a man or boy regarded asunpleasaht or wretchcd:e.g.a bird dog 搜罗人材的人:招揽生意的人.a clever dor 聪明伶俐的人dirty dog 坏小子;下流坯:卑污之人.a dumb dog

Medical management of victims contaminated with radionuclides after a “dirty bomb” attack

A wide spectrum of scenarios may lead to radiation incidents and the liberation of radioactive material. In the case of a terrorist attack by a "dirty bomb", there is a risk of mechanical and thermal trauma, external irradiation, superficial contamination and incorporation of radioactive material. The first treatment priority must be given to the care of trauma patients with life-threatening injuries, as the health effects of radiation occur with latency. Radionuclide incorporation will lead to a longer-lasting irradiation from inside the body, associated with a higher risk of stochastic radiation effects(e.g., occurrence of tumors) in the long run. It must be expected that victims with potentially incorporated radionuclides will far outnumber trauma patients. The elimination of radionuclides can be enhanced by the administration of decorporation agents such as(Ca) Diethylenetriaminepentaacetic acid(DTPA) or Prussian blue,reducing the radiological burden of the body. There is still no consensus whether decorporation treatment should be started immediately based only on a suspicion of radionuclide incorporation("urgent approach") or if the results of internal dosimetry confirming the necessity of a treatment should be awaited, accepting the delay caused by the measurements and computations("precautionary approach"). As the therapeutic effectiveness may be substantially decreased if treatment initiation is delayed only by several days, depending on the radionuclide, the physicochemical properties of the compounds involved and the route of absorption, we favor an "urgent approach" from a medical point of view. In doubt, it seems justified to treat victims by precaution, as the adverse effects of the medication seem minimal. However, in the case of a high number of victims, an "urgent treatment approach" may require a large number of daily doses of antidotes, and therefore, adequate investments in preparedness and antidote stockpiling are necessary.

Capacity Region of a Class of Gaussian Cognitive Degraded Broadcast Channel

This paper studies the cognitive broadcast channel in which the primary user communicates to the primary receiver, while the secondary user has noncausal knowledge of the primary radio's codeword and expects to communicate to two secondary receivers. Comparing with the existing cognitive radio channel which considers only one secondary receiver, cognitive broadcast channel studies the case that there are multiple secondary receivers.To this end, we investigate the fundamental limits of the performance of the Gaussian cognitive broadcast channel from the information theoretic perspective. Specifically, we derive the capacity region of the Gaussian cognitive degraded broadcast channel with weak interference.

Gaussian broadcast channel with lossy state reconstruction

We consider a state reconstruction problem where the additive state process of a Gaussian Broadcast Channel (GBC) is to be reconstructed at both receivers, subject to some distortion constraints. The state process we consider is Gaussian, independently and identically distributed, and known fully a-priori at the encoder. Each receiver has to perform a lossy estimation, to within some prescribed distortion tolerance under a squared error distortion criterion. The set-up also involves communicating messages across to the receivers, in addition to the estimation. The optimal trade-off between the distortions incurred at the receivers and the rates at which messages can be communicated, is of interest. We provide a complete characterization of the optimal rate vs. distortion performance.

Joint Transceiver Design for OFDM Systems

Orthogonal Frequency Division Multiplexing(OFDM) is an effective technique to deal with a frequency selective channel since it can convert the channel into some flat fading subchannels.However,very different output SNR values of the subchannels will lead to poor bit error performance when a linear equalizer and Equal Bit Allocation(EBA) are adopted in OFDM systems.So,we proposed three novel nonlinear Joint Transceiver(JT) schemes based on Zero-Forcing(ZF) criterion and Minimum Mean Square Error(MMSE) criterion respectively,which can transform all subchannels of an OFDM system into subchannels with identical channel gain.Thus,EBA is equivalent to the Optimum Bit Allocation(OBA) for these subchannels.Numerical analysis helps us to obtain the theoretical approximate BER values of the JT scheme.Simulation results verify the numerical analysis and confirm that the performance of our proposed JT scheme greatly outperforms the traditional linear equalizer with EBA at moderate and high SNR values.

Power duality for multi-antenna OFDM system in broadcast channel with user scheduling

This paper deals with design and analysis of user scheduling and power allocation for multi-antenna OFDM systems with DPC,ZF-DPC,ZF-BF and TDMA transmit strategies.We consider the general multi-user downlink scheduling problem and power minimization with multi-user rate constraints.According to the channel state,it is shown that there is a power optimal policy which selects a subset of users in each scheduling interval.We present user selection algorithms for DPC,ZF-DPC,ZF-BF and TDMA for multi-antenna OFDM system in broadcast channels,and we also present the practical water-filling solution in this paper.By the selected users with the consideration of fairness,we derive the power optimization algorithm with multi-user rate constraints.We also analyze the power duality of uplink-downlink for the transmit strategies of DPC,ZF-DPC and ZF-BF.Simulation results show that the present user-scheduling algorithm and power minimization algorithm can achieve good power performance,and that the scheduling algorithm can guarantee fairness.

Diagnostic Sign of Terra Firma-Forme Dermatosis

Background: Terra Firma-Forme Dermatosis (TFFD), a benign skin condition which presents with asymptomatic brown to black plaques which resemble dirty skin. Aim: To document a new case presentation with TFFD in the Arab region which is considered as one of the differential diagnoses of dirty neck. Case presentation: A 15-year-old girl presented with a history of asymptomatic brownish dirt-like lesion on the nape and sides of the neck for 4-years duration, not resolved by wash with water and soap and confused with other dermatoses like acanthosis nigricans or atopic dermatitis. The diagnosis of TFFD was confirmed when the lesions were completely resolved after gentle swabbing with 70% isopropyl alcohol. Conclusion: TFFD is rarely reported in Arab region and should be considered when evaluating cases of dirty neck-like presentation of atopic dermatitis or acanthosis nigricans.

Where’s that Great Society?

The other day I visited some folks who live on the near-northwest side of Chicago. Their home is uithin walking dictance of downtown①. but few things are like downtown in this home. It is on a tiny street lined with② old, dirty buildings.

浅谈同义形容词的语义程度及修饰语

英语同义形容词虽然同义,但在语义程度上存在着一定差别。使用同义形容词时,只有准确地把握其度,才能恰如其分地表达其意。在此,就同义形容词在程度上的差异及其程度状语的正确运用作一探讨。一、同义形容词在语义程度上的差异根据英国语言学家John & Liz Soars的观点。

浅谈英语习语中的“Dog”

1.a dirty dog行为无耻、卑鄙自私的家伙 You have finished all the whisky.you dirty dog. 你喝完了威士忌酒,你这卑鄙的家伙.2.a dog in the manger 占着茅坑不拉屎的人 Since you don’t know how to skate,why don’t you give your skates to me?Don’t be a dog in the manger.