关长交流与企业出口——基于关长流出地视角

官员交流是具有中国特色的官员治理制度,在促进地区经济发展和提升官员治理水平上卓有成就,成为一种引人注目的现象。本文基于2007—2013年间关长交流的自然实验,利用倍差法考察关长交流对关长流出地企业出口的影响。研究发现,关长交流会显著促进关长流出地的企业出口,并且这种影响只在关长流入地是出口较多的地区时发挥作用;这种影响也会因企业出口形式、关长能力和任期的不同而存在差异;关长交流的作用会在关长交流当期就发挥作用,但随着关长交流年份的延长,这种作用逐年下降,并在关长交流后的第三年消失;关长交流的作用仅通过影响流出地出口企业目的国范围来影响企业出口数量。

Optically pumped wavelength-tunable lasing from a GaN beam cavity with an integrated Joule heater pivoted on Si

Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.

司法效率、契约密集度与出口绩效:来自高院院长异地交流的证据

法律制度的完善和司法效率的提高有助于一国在契约密集型行业形成比较优势,因而有助于出口结构转换和升级。本文采用中国2003—2012年海关库数据,将2008年省级高级法院院长的异地交流轮岗政策作为一个自然实验,利用DDD方法系统评估法官异地交流是否通过提升司法效率进而改善出口结构。我们的研究发现:(1)本文研究的法官异地交流通过三种渠道影响出口结构,即法官异地交流的净效应、法官能力的影响、法官异地交流的异质性影响。法官异地交流的净效应为负,法官能力的影响和法官异地交流的异质性影响则取决于法官的个人特征,包括年龄、之前工作性质等。(2)动态效应回归结果发现,随着法官任职时间的延长,法官异地交流对出口的负影响逐渐变小;并且越接近交流年份,前任法官对出口表现的负向影响越大。(3)法官异地交流主要从"数量"上影响出口结构,在出口产品的"质量"方面影响甚微。法官异地交流对出口关系数量、出口目的国数量、出口产品数量有显著影响,对出口产品平均价格几乎没有影响。本文的研究通过了一系列的稳健性检验,对通过推进中国司法体制改革和健全司法监督机制来实现出口结构升级具有重要政策含义。

Real-time Audio &Video Transmission System Based on Visible Light Communication

With the increasing popularity of solid sate lighting devices, Visible Light Communication (VLC) is globally recognized as an advanced and promising technology to realize short-range, high speed as well as large capacity wireless data transmission. In this paper, we propose a prototype of real-time audio and video broadcast system using inexpensive commercially available light emitting diode (LED) lamps. Experimental results show that real-time high quality audio and video with the maximum distance of 3 m can be achieved through proper layout of LED sources and improvement of concentration effects. Lighting model within room environment is designed and simulated which indicates close relationship between layout of light sources and distribution of illuminance.

Screening of Chemical Agents for Controlling Spodoptera frugiperda in Corn Fields of Panmao Township,Yunnan Province

[Objectives]The paper was to effectively prevent and control the damage of Spodoptera frugiperda and to screen effective agents.[Methods]The block test of drug control was carried out,and the insect pest situation was investigated five times.[Results]150 mL/hm^(2) of 5%emamectin benzoate+600 mL/hm 2 of 5%lufenuron had better comprehensive control effect on S.frugiperda,and the corn yield reached 10100.55 kg/hm^(2).[Conclusions]The study provides a basis for scientific control of S.frugiperda.

Design of Wireless Optical Access System using LED

This paper develops a prototype to demonstrate a full-duplex wireless visible light communication (VLC) system based on Universal Serial Bus (USB) port. Combing with a USB 2.0 port on one board, it can achieve up to 2 Mbps bit rates error free, which is mainly limited to the USB bridge circuit, between two computers for data transmission, such as text, audio and video. Hyper Terminal and self-written software are used to allow setting the transmission data rate, control bits, check bits and achieve real-time transmission between any two mobile devices with a USB port. The work is based on the research of VLC local access network. This paper also shows the experimental results and the relationship between system transmission eye diagram and bit rate.

Channel Simulation of Non-imaging Optical MIMO Communication

This paper reports a channel simulation of an indoor optical wireless multiple-input-multiple-output (MIMO) system with non-imaging receivers. The system consists of a 2×2 array of white light-emitting diodes (LEDs) and 2×2 array of PDs. An overview of the model specifications, channel impulse response and channel capacity are demonstrated in this paper. The distribution of the first reflection is analyzed. The effect of SNR and the location of receivers on non-imaging optical MIMO communications are investigated. In addition, by moving the receivers, the optimal location of the communication is found.

Size Effect of Impact Abrasive Particles on Wear and Surface Hardening Behavior of High‑Manganese Steel

The size effect of impact abrasive particles on wear and surface hardening behavior of high-manganese steel was studied.Impact wear tests were carried out on MLD-10 tester with abrasive particle sizes of 6.0–0.75 mm,respectively.The results showed that the impact wear behavior and surface hardening mechanism of high-manganese steel were affected by the size of abrasive particles.A critical size of abrasive particle might exhibit to distinguish the impact wear behavior.When the abrasive particle size was larger than 0.75 mm,the wear mass loss generally showed a decreasing trend with the decrease of the abrasive particle size.Dislocation strengthening and mechanical twinning contributed to the good work hardening behavior.However,effective surface hardening layer could not be formed for sample tested with particle size of 0.75 mm and the wear mass loss was the highest among all the conditions.The weak hardening effect led to the sharp increase of the wear mass loss.Press-in abrasives could be observed on the wear surface when the abrasive particle size was larger than 0.75 mm.The press-in abrasives were peeled off from the wear surface and broken,leaving deep grooves and peeling pits.Material exchange with the sample would occur with the flow of abrasives.A large area of furrow was formed on the wear surface.For particle size of 0.75 mm,aggregated abrasives formed a dynamic buffer layer on the surface and the stress distribution was more even.The formation of buffer layer would lower the effect of the impact load and the work hardening effect could not be fully activated.The mutual extrusion among the abrasives,friction wheel and sample caused plastic deformation of the worn surface during impact test.The present study would help guiding to select the application field of high-manganese steel more precisely.

Ice-volume and insolation influences on hydroclimate changes in central eastern China during the antepenultimate glacial period

The rainfall changes in East Asian summer monsoon(EASM)regions on the orbital timescale remain controversial due to the lack of reliable rainfall records.Here,we present new multiproxy records(δ^(18)O,δ^(13)C,Sr/Ca and Mg/Ca)of a230Thdated stalagmite from Hulu Cave in central eastern China.Multiproxy records reconstruct a regional hydroclimate history from 340 to 261 kyr BP(thousand years before present),approximately covering the antepenultimate glacial period.Theδ^(18)O record is dominated by the precessional cycles,suggesting that EASM responds to changes in Northern Hemisphere summer insolation(NHSI)on the orbital timescale.Significant correlations amongst theδ^(13)C,Sr/Ca and Mg/Ca suggest that a common factor,i.e.,the local hydrological cycle,controlled their variability,and their leading principal component can be used as a proxy linked to regional rainfall.This composite record bears a good similarity to those from the Chinese Loess Plateau,showing a gradually decreasing rainfall during the antepenultimate glacial period,consistent with changes in global ice volume.Superimposed on the long-term trend,three relative wetter intervals were responding to the higher NHSI periods,suggesting that EASM rainfall variability was induced by integrated effects of global ice volume and NHSI.The increased ice sheets and lower NHSI resulted in an increased meridional temperature gradient and southward shift of the westerlies,which shortened the duration of Meiyu and midsummer rainfall.The differences between the rainfall record and the stalagmiteδ^(18)O record indicate that the latter represents the overall EASM intensity linked to monsoon circulation,but does not directly reflect the rainfall changes at the cave sites.

Electrically pumped optomechanical beam GaN-LED accelerometer based on the quantum-confined Stark effect

Micro-nano optomechanical accelerometers are widely used in automobile,aerospace,and other industrial applications.Here,we fabricate mechanical sensing components based on an electrically pumped GaN light-emitting diode(LED)with a beam structure.The relationship between the blueshift of the electroluminescence(EL)spectra and the deformation of the GaN beam structure based on the quantum-confined Stark effect(QCSE)of the InGaN quantum well(QW)structure is studied by introducing an extra mass block.Under the equivalent acceleration condition,in addition to the elastic deformation of GaN-LED,a direct relationship exists between the LED’s spectral shift and the acceleration’s magnitude.The extra mass block(gravitational force:7.55×10^(-11)N)induced blueshift of the EL spectra is obtained and shows driven current dependency.A polymer sphere(PS;gravitational force:3.427×10^(-12)N)is placed at the center of the beam GaN-LED,and a blueshift of 0.061 nm is observed in the EL spectrum under the injection current of 0.5 mA.The maximum sensitivity of the acceleration is measured to be 0.02 m∕s^(2),and the maximum measurable acceleration is calculated to be 1.8×10^(6)m∕s^(2).It indicates the simultaneous realization of high sensitivity and a broad acceleration measurement range.This work is significant for several applications,including light force measurement and inertial navigation systems with high integration ability.

斜扩散过程的构造、性质及其应用

斜扩散过程是一类特殊的扩散过程,它所满足的随机微分方程中含有局部时项.由于这类过程具有特殊的路径性质,使得它在物理和生物等领域有着广泛的应用.本文先从斜Brown运动出发,概括总结了斜Brown运动的两种构造方式、离散逼近形式和联合概率分布.在斜Brown运动的基础上,本文给出斜Ornstein-Uhlenbeck (OU)过程和斜分支过程的定义,并展示了它们的诸如转移密度、首达时分布等概率性质.最后介绍了斜扩散过程的一些应用.

Bioptical microcycles of laminated speleothems from China and their chronological significance

Interfaces of microlayers, in most stalagmites from China, consist of opaque and organic materials. Observed with microscope, the interfaces seem dark under transmitted light and luminiferous under reflected fluorescent light. Stalagmites in which the two optical characters are unified spatially would be most suitable for cross-dating use, and can play an important role in the study on speleochronology and speleoclimatology.

On the Collision Local Time of Fractional Brownian Motions

在这篇论文，碰撞本地人时间的存在和光滑为二个独立部分 Brownian 运动被证明，通过 L^2 集中和混乱扩大。而且，碰撞本地人时间过程的整齐被学习。

TIMS U-series ages of speleothems from the Tangshan caves, Nanjing

U-series ages of a set of speleothem samples from the two caves near Tangshan Town, Nanjing, determined by thermal ionization mass spectrometry (TIMS), range from older than 500 KaBP to around 20 kaBP. These dated speleothems with unequivocal stratigraphic layers in cave sediments provide basic data to establish a geochronologic sequence for the

Perovskite light-emitting/detecting bifunctional fibres for wearable LiFi communication

Light fidelity(LiFi),which is emerging as a compelling technology paradigm shifting the common means of highcapacity wireless communication technologies,requires wearable and full-duplex compact design because of its great significance in smart wearables as well as the‘Internet of Things’.However,the construction of the key component of wearable full-duplex LiFi,light-emitting/detecting bifunctional fibres,is still challenging because of the conflicting process between carrier separation and recombination,as well as the highly dynamic film-forming process.Here,we demonstrate light-emitting/detecting bifunctional fibres enabled by perovskite QDs with hybrid components.The hybrid perovskite inks endow fibres with super-smooth QD films.This,combined with the small exciton binding energy and high carrier mobility of perovskite QDs,enables successful integration of electroluminescence and photodetection into monofilaments.The bifunctional fibres possess the narrowest electroluminescence full width at half maximum of ~19 nm and,more importantly,the capability for simultaneously transmitting and receiving information.The successful fabrication of narrow emission full-duplex LiFi fibres paves the way for the fabrication and integration of low crosstalk interoperable smart wearables.

Full-duplex light communication with a monolithic multicomponent system

A monolithic multicomponent system is proposed and implemented on a III-nitride-on-silicon platform,whereby two multiple-quantum-well diodes(MQW-diodes)are interconnected by a suspended waveguide.Both MQW-diodes have an identical low-In-content InGaN/Al0.10Ga0.90N MQW structure and are produced by the same fabrication process flow.When appropriately biased,both MQW-diodes operate under a simultaneous emission-detection mode and function as a transmitter and a receiver at the same time,forming an in-plane full-duplex light communication system.Real-time full-duplex audio communication is experimentally demonstrated using the monolithic multicomponent system in combination with an external circuit.

Optimal portfolio and consumption selection with default risk

我们与可默认的安全调查一个最佳的公事包和消费选择问题。在经过消费最大化一般水准的期望的打折的实用程序的目标下面，一个动态编程原则被使用导出一双秒顺序有坡度限制的寓言的 Hamilton-Jacobi-Bellman (HJB ) 方程。我们探索由一个粘性解决方案的方程接近并且描绘的这些 HJB 缺省以后并且预先默认作为 HJB 方程的抑制粘性答案的唯一的对珍视函数。

Non-destructive corrosion study on a magnesium alloy with mechanical properties tailored for biodegradable cardiovascular stent applications

AnMg-2Zn-0.6Zr-0.6Nd alloy for biodegradable cardiovascular stent applications was prepared through indirect extrusion. The alloy exhibited a superior combination of tensile yield strength(TYS), ultimate tensile strength(UTS) and elongation(EL) of about 269 MPa, 298 MPa and 25.6 %, respectively. In addition,the non-destructive electrochemical frequency modulation(EFM) technique was used for the first time to investigate the corrosion behavior of Mg alloys combined with electrochemical impedance spectroscopy(EIS) in Dulbecco’s Modified Eagle’s Medium(DMEM) and in Hank’s solution. Compared with the corrosion rate of 0.07 mm/year in Hank’s solution, lower corrosion rate of 0.03 mm/year was achieved in DMEM. The significant differences between the corrosion rate trends were discussed and related with the composition of the corrosion layer formed. Depending on the biomimetic fluids tested, different corrosion products were precipitated on the alloy’s surface: a compact and homogeneous layer of Mg_(x)Ca_(y)(PO_(4))_(z) and Zn(OH)_(2) and organic compounds was formed in DMEM, whereas a partial coverage of Mg_(x)Ca_(y)(PO_(4))_(z) and Zn(OH)_(2) was formed in Hank’s solution.

Jump Type Cahn-Hilliard Equations with Fractional Noises

The authors explore a class of jump type Cahn-Hilliard equations with fractional noises. The jump component is described by a (pure jump) Lévy space-time white noise. A fixed point scheme is used to investigate the existence of a unique local mild solution under some appropriate assumptions on coefficients.

Multiscale analysis of Asian Monsoon over the past 640 ka

The empirical mode decomposition(EMD) method is used to re-analyse the high-resolution and precisely-dated stalagmite record from Chinese caves over the past 640 ka. Results show that(1) the variation in the Asian Monsoon can be completely decomposed into ten quasiperiod oscillations, among which the precession and semiprecession band oscillations are the most prominent periodicities, with contribution rates of 31.1% and 30.7%, respectively;(2) the cross-spectrum analysis of the semiprecession component and bi-hemisphere insolation(BHI) are strongly correlated, indicating an amplified response of precipitation and temperature variability to the interhemispheric insolation in the low-latitude regions, thus further affecting the intensity of the Asian Monsoon;(3) on millennial timescales, obvious oscillations at the 5 ka and 1–2 ka bands roughly correspond to the classical Bond and Dansgaard-Oeschger(DO) cycles. Additionally, a strong correlation is found between the detrended stalagmite δ18 O records and Ca/Sr sequence from the North Atlantic(especially at the 5 ka band). This result means that the 5 ka cycle is characteristic of the glacial-interglacial cycle since the middle and late Pleistocene and may imply that climate change on the millennial timescale is the result of an interaction between global ice volume and insolation.