基于微型振子阵列的可穿戴触觉电视的研发

盲人因视觉障碍无法通过光学获取信息,本文基于换能原理设计了一种触觉电视,可把图像数据转换为振动数据,使人体通过皮肤触觉作为媒介接收信息,可帮助盲人使用触觉感知周围事物和图像信息。

反馈寻求行为对制造业服务化的跨层次影响机制

基于制造业企业301份调查问卷数据提出并验证反馈寻求、双元创新、组织整合惯性、组织结构特性、组织公平感和制造业服务化的跨层次有中介的调节模型。实证结果表明反馈寻求行为正向影响制造业服务化,并以组织双元创新为中介;此外,组织整合惯性,组织结构特性和组织公平感在其中产生正向和负向的调节作用。研究结论对我国整体制造业企业如何有效的利用反馈寻求行为和双元创新促进制造业服务化具有现实借鉴意义。

高分数GNFs/6061Al基复合材料的放电等离子体烧结制备及其显微组织与性能

采用放电等离子体烧结(SPS)工艺在610℃制备30%~50%(质量分数)纳米石墨片(GNF)/6061Al基复合材料,研究烧结压力及GNF含量对复合材料显微组织和力学、热学性能的影响。结果表明,SPS有效抑制GNFs/6061Al基复合材料中Al4C3等界面反应产物的生成。随着GNF含量的增加,GNFs团聚程度增加,取向分布程度降低,复合材料致密度、抗弯强度及热膨胀系数(CTE)下降,X−Y方向热导率(TC)增大。提高烧结压力,有助于降低GNFs团聚程度,GNFs沿X−Y方向择优分布越明显,复合材料致密度、抗弯强度及TC增大,CTE下降。在610℃、55 MPa下烧结的50%GNFs/6061Al基复合材料的性能最佳,抗弯强度为72 MPa,TC及CTE分别为254 W/(m·K)和8.5×10^(−6) K^(−1)(室温~100℃,X−Y方向),以及55 W/(m·K)和9.7×10^(−6) K^(−1)(Z方向)。

基于AI和3D扫描技术的VR全息直播系统的设计实现与应用

世界由三维空间构成,但传统摄像机只能拍摄二维画面,为实现全息传输,本文对全息直播系统进行设计与实现,使平面视听跃升为VR全息视听。同时还介绍了3D扫描立体成像技术、VR技术、全息节目采编制作技术、测试与分析、AI与多应用场景。

百万千瓦级核电厂升压站继电保护设备状态的智能检修方法研究

随着核电厂装机容量的不断扩大及智能技术的发展,传统的继电保护设备检修模式效率较低,矛盾日益突出。针对上述问题,文中对百万千瓦级核电厂升压站继电保护设备状态的智能检修方法进行了深入的研究。基于继电保护系统二次回路、断路器回路的基本原理,设计了继电保护设备状态智能检修方案。分别从基础数据分析、状态量的确定、状态评价标准、状态评价体系4个方面对继电保护设备状态进行评价,最后实现该智能检修方案并进行测试。结果表明,该智能检修方法具备良好的预期经济效益,可提高升压站的供电可靠性,降低核电厂的运维成本。

Micro-impulse and plasma plume produced by irradiating aluminum target with nanosecond laser pulses in double-pulse scheme

The micro-impulse generated by ablating an aluminum target in double-pulse laser bursts with different interpulse delays was investigated using a torsion pendulum.The plasma plume was simultaneously visualized using high-speed photography to analyze the coupling mechanism of the ablation impulse.The experiment was carried out using a pulsed laser with a pulse width of 8 ns and a wavelength of 1064 nm.The experimental results show that an impulse with an interpulse delay of 60 ns is roughly 60%higher than that with no delay between the two pulses,when the energy of both laser pulses is 50 m J.Therefore,double-pulse schemes could enhance the ablation impulse under certain conditions.This is because the ablation of the first laser pulse changes the optical properties of the aluminum target surface,increasing the absorptivity.However,the ablation impulse is reduced with a time delay of 20 ns when the energy of both laser pulses is100 mJ or 150 mJ.It can be concluded that the plasma produced by ablating the aluminum with the first pulse shields the second laser pulse.To summarize,the experimental results show that different delay times in a double-pulse scheme have a significant effect on the ablation impulse.The study provides a reference for the optimization of the parameters when laser ablation propulsion with a double-pulse scheme is applied in the fields of space debris removal,laser ablation thrusters,and so on.

General seismic wave and phase detection software driven by deep learning

We developed an automatic seismic wave and phase detection software based on PhaseNet,an efficient and highly generalized deep learning neural network for P-and S-wave phase picking.The software organically combines multiple modules including application terminal interface,docker container,data visualization,SSH protocol data transmission and other auxiliary modules.Characterized by a series of technologically powerful functions,the software is highly convenient for all users.To obtain the P-and S-wave picks,one only needs to prepare threecomponent seismic data as input and customize some parameters in the interface.In particular,the software can automatically identify complex waveforms(i.e.continuous or truncated waves)and support multiple types of input data such as SAC,MSEED,NumPy array,etc.A test on the dataset of the Wenchuan aftershocks shows the generalization ability and detection accuracy of the software.The software is expected to increase the efficiency and subjectivity in the manual processing of large amounts of seismic data,thereby providing convenience to regional network monitoring staffs and researchers in the study of Earth's interior.

维生素D补充与儿童哮喘的系统评价及meta分析

目的探讨维生素D补充与儿童哮喘的相关性。方法纳入对象为基于社区、学校和医疗机构的儿童,暴露因素为维生素D补充,观察哮喘相关结局的随机病例对照研究。计算机检索PubMed、Embase、Cochrane Library数据库,检索截止日期为2018年12月30日。对纳入的文献行筛选、资料提取及方法学质量评价,采用Cochrane风险偏倚评估工具,应用Revman5.3软件进行meta分析。结果共有11项符合纳入标准的随机对照试验,最终纳入9项研究,其中干预组共361例,对照组共341例。meta分析结果显示:2组血清25(OH)D水平比较差异无统计学意义(P=0.13);以是否联合特异性免疫治疗进行亚组分析,合并效应均数差(MD)分别为9.44nmol/L和15.23nmol/L;干预组哮喘发作次数显著低于对照组,差异有统计学意义(P<0.0001);2组肺功能和哮喘症状评分比较,差异无统计学意义(P>0.05)。结论补充维生素D可以减少哮喘发作,对血清25(OH)D水平、肺功能和哮喘症状评分的作用有限;由于有其他潜在的混杂因素,未来需要进行大规模、长时间、精心设计的随机对照试验来了解维生素D对儿童哮喘的治疗作用。

继电保护装置自动化检测系统的研究及应用

电力系统中所涉及到的继电保护装置可以在系统运行发生特殊情况时发出报警信号,让工作人员接收到故障信息,并及时采取科学、合理的解决措施,以此确保整个系统的稳定运行。在当前科学技术不断发展的背景下,对电力系统继电保护装置应用的过程中出现了一种自动化检测系统。若是在系统运行过程中电路元件发生故障问题,这一自动化装置就会自动检测到故障,并将这一信息发送给工作人员。装置也会启动跳闸命令,从而保护好系统中的各个电路元件和设备。这一自动化检测系统具有调节和调控监测的功能,能够及时对故障进行有效感应和判断。本文主要分析了在继电保护过程中经常会出现的故障,探究了自动化检测系统对继电保护的重要意义,并对这一系统的检测技术方案、检测步骤以及控制方法进行分析。

Defined Contribution Pension Planning with the Return of Premiums Clauses and HARA Preference in Stochastic Environments

This paper studies a defined contribution(DC)pension fund investment problem with return of premiums clauses in a stochastic interest rate and stochastic volatility environment.In practice,most of pension plans were subject to the return of premiums clauses to protect the rights of pension members who died before retirement.In the mathematical modeling,we assume that a part of pension members could withdraw their premiums if they died before retirement and surviving members could equally share the difference between accumulated contributions and returned premiums.We suppose that the financial market consists of a risk-free asset,a stock,and a zero-coupon bond.The interest rate is driven by a stochastic affine interest rate model and the stock price follows the Heston’s stochastic volatility model with stochastic interest rates.Different fund managers have different risk preferences,and the hyperbolic absolute risk aversion(HARA)utility function is a general one including a power utility,an exponential utility,and a logarithm utility as special cases.We are concerned with an optimal portfolio to maximize the expected utility of terminal wealth by choosing the HARA utility function in the analysis.By using the principle of dynamic programming and Legendre transform-dual theory,we obtain explicit solutions of optimal strategies.Some special cases are also derived in detail.Finally,a numerical simulation is provided to illustrate our results.

Blade bowing effects on radial equilibrium of inlet flow in axial compressor cascades

The circumferentially averaged equation of the inlet flow radial equilibrium in axial compressor was deduced. It indicates that the blade inlet radial pressure gradient is closely related to the radial component of the circumferential fluctuation（CF） source item. Several simplified cascades with/without aerodynamic loading were numerically studied to investigate the effects of blade bowing on the inlet flow radial equilibrium. A data reduction program was conducted to obtain the CF source from three-dimensional（3D） simulation results. Flow parameters at the passage inlet were focused on and each term in the radial equilibrium equation was discussed quantitatively. Results indicate that the inviscid blade force is the inducement of the inlet CF due to geometrical asymmetry. Blade bowing induces variation of the inlet CF, thus changes the radial pressure gradient and leads to flow migration before leading edge（LE） in the cascades. Positive bowing drives the inlet flow to migrate from end walls to mid-span and negative bowing turns it to the reverse direction to build a new equilibrium. In addition, comparative studies indicate that the inlet Mach number and blade loading can efficiently impact the effectiveness of blade bowing on radial equilibrium in compressor design.

Ultrafast,accurate,and robust localization of anisotropic dipoles

The resolution of single molecule localization imaging techniques largely depends on the precision of localization algorithms.However,the commonly used Gaussian function is not appropriate for anisotropic dipoles because it is not the true point spread function.We derived the theoretical point spread function of tilted dipoles with restricted mobility and developed an algorithm based on an artifi cial neural network for estimating the localization,orientation and mobility of individual dipoles.Compared with fi tting-based methods,our algorithm demonstrated ultrafast speed and higher accuracy,reduced sensitivity to defocusing,strong robustness and adaptability,making it an optimal choice for both two-dimensional and threedimensional super-resolution imaging analysis.

Commuting variety of Witt algebra

Let g = W1 be the Witt algebra over an algebraically closed field k of characteristic p 〉 3, and let ∮（g） = {（x,y） ∈ g×g [x,y] = 0} be the commuting variety of g. In contrast with the case of classical Lie algebras of P. Levy [J. Algebra, 2002, 250： 473-484], we show that the variety ∮（g） is reducible, and not equidimensional. Irreducible components of ∮（g） and their dimensions are precisely given. As a consequence, the variety ∮（g） is not normal.

Azure-winged magpies solve string-pulling tasks by partial understanding of the physical cognition

String-pulling is one of the most widely used paradigms in an imal cog nition research. We in vestigated how azure-wi nged magpies Cyanopica cyan us solve multiple-string problems that they have never encountered before. In Experiment 1, the strings were arranged in parallel, slanted, or crossed to investigate what rules azure-winged magpies use to solve multiple spatial relations of strings. Experiment 2 assessed whether the subjects understood the connection between the string and the bait while taking advantage of broken strings. In Experiment 3, the subjects were confronted with strings of different lengths attached to rewards in order to explore whether the string length, as a proxy for the pulling efficiency or reward distanee, was crucial for the birds' choice of which string to pull. Gen erally, the birds were successful in tasks where the reward was close to the correct string's end, and they relied on a "proximity rule" in most cases. The results showed that azure-winged magpies had a partial understanding of the physical principles underlying the string-pulling but were stumped by complex spatial relations. They likely relied on simple strategies such as the proximity rule to solve the tasks. The effects of in dividual difference and experiential learning on string-pulling performance are also discussed.

Light-induced protein translocation by genetically encoded unnatural amino acid in Caenorhabditis elegans

Dear Editor,Living systems such as Caenorhabditis elegans are organized by interaction networks of biopolymer and small mol-ecules.The molecular engineering of specifi c targets to monitor and control these biological molecules has led to significant advances in our understand-ing of how biological systems are organ-ized,maintain themselves and disin-tegrate(Prescher and Bertozzi,2005).For instance,green fl uorescent protein(GFP)derived from jellyfi sh Aequorea Victoria helps us to accurately locate and observe proteins over long term periods.In addition,many novel LOV(light,oxy-gen,or voltage)domains such as LOV2-Jαand Vivid offer the possibility of cell-based motility management and tissue-based gene expression control(Wu et al.,2009;Wang et al.,2012).

C13C4.5/Spinster, an evolutionarily conserved protein that regulates fertility in C. elegans through a lysosome-mediated lipid metabolism process

Lipid droplets, which are conserved across almost all species, are cytoplasmic organelles used to store neutral lipids. Identification of lipid droplet regulators will be conducive to resolving obesity and other fat-associated diseases. In this paper, we selected 11 candidates that might be associated with lipid metabolism in Caenorhabditis elegans . Using a BODIPY 493/503-based flow cytometry screen, 6 negative and 3 positive regulators of fat content were identified. We selected one negative regulator of lipid content, C13C4.5 , for future study. C13C4.5 was mainly expressed in the worm intestine. We found that this gene was important for maintaining the metabolism of lipid droplets. Biochemical results revealed that 50% of triacylglycerol (TAG) was lost in C13C4.5 knockout worms. Stimulated Raman scattering (SRS) signals in C13C4.5 mutants showed only 49.6% of the fat content in the proximal intestinal region and 86.3% in the distal intestinal region compared with wild type animals. The mean values of lipid droplet size and intensity in C13C4.5 knockout animals were found to be significantly decreased compared with those in wild type worms. The LMP-1-labeled membrane structures in worm intestines were also enlarged in C13C4.5 mutant animals. Finally, fertility defects were found in C13C4.5 ( ok2087 ) mutants. Taken together, these results indicate that C13C4.5 may regulate the fertility of C. elegans by changing the size and fat content of lipid droplets by interfering with lysosomal morphology and function.

Advanced Process and Electron Device Technology

This article reviews advanced process and electron device technology of integrated circuits,including recent featuring progress and potential solutions for future development.In 5 years,for pushing the performance of fin field-effect transistors(FinFET)to its limitations,several processes and device boosters are provided.Then,the three-dimensional(3 D)integration schemes with alternative materials and device architectures will pave paths for future technology evolution.Finally,it could be concluded that Moore’s law will undoubtedly continue in the next 15 years.

Portfolio Selection with Random Liability and Affine Interest Rate in the Mean-Variance Framework

This paper studies a dynamic mean-variance portfolio selection problem with random liability in the affine interest rate environment, where the financial market consists of three assets: one risk-free asset, one risky asset and one zero-coupon bond. Assume that short rate is driven by affine interest rate model and liability process is described by the drifted Brownian motion, in addition, stock price dynamics is affected by interest rate dynamics. The investors expect to look for an optimal strategy to minimize the variance of the terminal surplus for a given expected terminal surplus. The efficient strategy and the efficient frontier are explicitly obtained by applying dynamic programming principle and Lagrange duality theorem. A numerical example is given to illustrate our results and some economic implications are analyzed.

Ultrastable low-cost colloidal quantum dot microlasers of operative temperature up to 450 K

Quantum dot microlasers,as multifunaional optical source components,are of great importance for full-color highpixel display,miniaturized coherent lighting,and on-chip integrated photonic and electronic circuits.Since the first synthesis of colloidal quantum dots(CQD)in the 1990s,motivation to realize high-performance low-cost CQD micro-/nanolasers has been a driving force for more than three decades.However,the low packing density,inefficient coupling of CQDs with optical cavities,and the poor thermal stability of miniaturized complex systems make it challenging to achieve practical CQD microVnanolasers,especially to combine the continuous working ability at high temperatures and the low-cost potential with mass-produced synthesis technologies.Herein,we developed closepacked CQD-assembled microspheres and embedded them in a silica matrix through the rapid self-aggregation and solidification of CdSe/ZnS CQD.This technology addresses the core issues of photoluminescence(PL)quenching effect and low optical gain in traditional CQD laser research.High-efficiency low-threshold CQD microlasers are demonstrated together with long-playing(40 min)working stability even at 450 K under pulsed laser excitation,which is the highest operational temperature for CQD lasers.Moreover,single-mode CQD microlasers are obtained with tunable wavelengths across the entire visible spectral range.The chemosynthesis process supports the mass-produced potential of high-density integrated CQD microlasers,promoting CQD-based low-cost high-temperature microdevices.

基于DNA条形码的红翅大小蠹和黄杉大小蠹分子鉴定

外来有害生物的快速准确鉴定有助于提高口岸检疫效率。红翅大小蠹(Dendroctonus rufipennis)和黄杉大小蠹(D. pseudotsugae)作为大小蠹属的非中国种是我国口岸原木检疫中频繁截获的检疫性有害昆虫。本研究以mtDNA COI基因5′端和3′端序列为标记对红翅大小蠹与黄杉大小蠹的11个样本开展分子鉴定有效性评价。结果显示,当以COI基因5′端和3′端为靶标时,两种大小蠹间的平均遗传距离分别为0.181和0.144,是种内遗传距离的60.3和48倍,且种内、种间遗传距离间无重叠现象,在系统发育树上都能聚为独立的分支,表明mtDNA COI基因5′端和3′端序列均可有效区分红翅大小蠹与黄杉大小蠹。