Traffic Engineering in Dynamic Hybrid Segment Routing Networks

The emergence of Segment Routing(SR)provides a novel routing paradigm that uses a routing technique called source packet routing.In SR architecture,the paths that the packets choose to route on are indicated at the ingress router.Compared with shortest-path-based routing in traditional distributed routing protocols,SR can realize a flexible routing by implementing an arbitrary flow splitting at the ingress router.Despite the advantages of SR,it may be difficult to update the existing IP network to a full SR deployed network,for economical and technical reasons.Updating partial of the traditional IP network to the SR network,thus forming a hybrid SR network,is a preferable choice.For the traffic is dynamically changing in a daily time,in this paper,we propose a Weight Adjustment algorithm WASAR to optimize routing in a dynamic hybrid SR network.WASAR algorithm can be divided into three steps:firstly,representative Traffic Matrices(TMs)and the expected TM are obtained from the historical TMs through ultrascalable spectral clustering algorithm.Secondly,given the network topology,the initial network weight setting and the expected TM,we can realize the link weight optimization and SR node deployment optimization through a Deep Reinforcement Learning(DRL)algorithm.Thirdly,we optimize the flow splitting ratios of SR nodes in a centralized online manner under dynamic traffic demands,in order to improve the network performance.In the evaluation,we exploit historical TMs to test the performance of the obtained routing configuration in WASAR.The extensive experimental results validate that our proposed WASAR algorithm has superior performance in reducing Maximum Link Utilization(MLU)under the dynamic traffic.

Non-volatile optical memory in vertical van der Waals heterostructures

Emulating synaptic plasticity in an artificial neural network is crucial to mimic the basic functions of the human brain.In this work,we report a new optoelectronic resistive random access memory(ORRAM)in a three-layer vertical heterostructure of graphene/Cd Se quantum dots(QDs)/graphene,which shows non-volatile multi-level optical memory under optical stimuli,giving rise to light-tunable synaptic behaviors.The optical non-volatile storage time is up to^450 s.The device realizes the function of multi-level optical storage through the interlayer changes between graphene and QDs.This work highlights the feasibility for applying two-dimensional(2D)materials in ORRAM and optoelectronic synaptic devices towards artificial vision.

Study on High-frequency Callus Induction From Aseptic Plantlets of Anthuium andraeanum

[Objectives]This study was conducted to improve the efficiency of callus induction and redifferentiation,and construct high-frequency plant regeneration techniques of tissue culture in Anthuium andraeanum.[Methods]The effects of different genotypes,explant types and hormonal conditions on callus induction and re-differentiation of A.andraeanum were studied by using the aseptic A.andraeanum test-tube plantlets as test materials.[Results]Among the four kinds of aseptic A.andraeanum plantlets,the callus induction using stem segments with leaves was the best,followed by stem segments and leaves,and the petioles were the worst;among the six A.andraeanum varieties tested,the callus production rates of four varieties reached 100%;and the callus differentiation rate reached 93.3%-100%through the organogenesis pathway,and the suitable differentiation medium was 1/2MS+ZT 0.5 mg/L+2,4-D 0.1 mg/L.[Conclusions]The research results provide a new experimental basis for optimizing the technical system of A.andraeanum rapid propagation.

Cloning and Expression Analysis of Heat Shock Protein Gene DpHsp70 in Dahlia

[Objectives]This study was conducted to investigate the relationship between HSPs and the response of high temperature stress.[Methods]Molecular biological techniques were applied to clone and analyze the gene sequence of DpHsp70 gene.The changes in the expression of DpHsp70 gene under high temperature stress and exogenous salicylic acid(SA)were observed and further analyzed by qRT PCR.[Results]The coding region of the Dahlia DpHsp70 gene was 705 bp,encoding 234 amino acid residues(GenBank accession number:MH102288).Aligned with Compositae plants,the Dahlia DpHsp70 gene shared more than 83%homology in gene sequence while 99%-100%homology in amino acid sequence.Under the 35℃high temperature stress,the expression of DpHsp70 gene in Dahlia petals significantly increased.Meanwhile,the expression of DpHsp70 gene further increased under SA at 35℃temperature,which was significantly higher than those of the control group and the 35℃high temperature stress treatment group.It was demonstrated that the Hsp70 gene in Compositae is with highly conservative property and its expression could be up-regulated in response to high temperature stress.It can also be concluded that applying exogenous SA can improve the high temperature resistance of Dahlia.[Conclusions]This study provides a new experimental basis for elucidating the physiological function and mechanism of Dahlia in response to high temperature stress.

Study on the Genetic Transformation Conditions of Begonia wallichiana L.with Leaf Disc Method and Corresponding Identification Techniques

[Objectives]This study was conducted to improve the Agrobacterium-mediated genetic transformation system of Begonia wallichiana.[Methods]With sterilized tube seedling leaves as the recipient material and GFP as the reporter gene,optimization experiments were carried out in terms of infection time and method,co-cultivation time and method,and PCR detection technology.[Results]The transformation effect was better under the conditions of shaking Agrobacterium liquid,infection time of 1-2 h,and co-cultivation on sterilized filter paper for 2 d.After co-cultivation,the recipient material was first subjected to recovery culture,and then used for Hyg gradient screening,which was conducive to obtaining resistant transformants.The designed specific PCR detection technology could quickly identify false positives in resistant regenerated plants,and the proportion of transgenic plants was 16.7%.[Conclusions]The research results provide a new technical reference for the genetic transformation of ornamental plants.

Miniaturized retractable thin-film sensor for wearable multifunctional respiratory monitoring

As extremely important physiological indicators,respiratory signals can often reflect or predict the depth and urgency of various diseases.However,designing a wearable respiratory monitoring system with convenience,excellent durability,and high precision is still an urgent challenge.Here,we designed an easy-fabricate,lightweight,and badge reel-like retractable selfpowered sensor(RSPS)with high precision,sensitivity,and durability for continuous detection of important indicators such as respiratory rate,apnea,and respiratory ventilation.By using three groups of interdigital electrode structures with phase differences,combined with flexible printed circuit boards(FPCBs)processing technology,a miniature rotating thin-film triboelectric nanogenerator(RTF-TENG)was developed.Based on discrete sensing technology,the RSPS has a sensing resolution of 0.13 mm,sensitivity of 7 P·mm^(−1),and durability more than 1 million stretching cycles,with low hysteresis and excellent anti-environmental interference ability.Additionally,to demonstrate its wearability,real-time,and convenience of respiratory monitoring,a multifunctional wearable respiratory monitoring system(MWRMS)was designed.The MWRMS demonstrated in this study is expected to provide a new and practical strategy and technology for daily human respiratory monitoring and clinical diagnosis.

Improving the Initial Coulombic Efficiency of Carbonaceous Materials for Li/Na‑Ion Batteries:Origins,Solutions,and Perspectives

Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great efforts have been devoted to developing high-performance carbonaceous materials with high capacity,long life span,and excellent rate capability,the low initial Coulombic efficiency(ICE)of high-capacity carbonaceous materials seriously limits their practical applications.Various methods have been successfully exploited,and a revolutionary impact has been achieved through the utilization of different techniques.Different carbonaceous materials possess different ion storage mechanisms,which means that the initial capacity loss may vary.However,there has rarely been a special review about the origins of and progress in the ICE for carbonaceous materials from the angle of the crystal structure.Hence,in this review,the structural differences between and ion storage mechanisms of various carbonaceous materials are first introduced.Then,we deduce the correlative factors of low ICE and thereafter summarize the proposed strategies to address these issues.Finally,some challenges,perspectives,and future directions on the ICE of carbonaceous materials are given.This review will provide deep insights into the challenges of improving the ICE of carbonaceous anodes for high-energy Li/Na-ion batteries,which will greatly contribute to their commercialization process.

Deterministic Synthesis of Pd Nanocrystals Enclosed by High-Index Facets and Their Enhanced Activity toward Formic Acid Oxidation

Noble-metal nanocrystals enclosed by high-index facets are of growing interest due to their enhanced catalytic performance in a variety of reactions.Herein,we report the deterministic synthesis of Pd nanocrystals encased by high-index facets by controlling the rate of deposition(V_(deposition))relative to that of surface diffusion(V_(diffusion)).For octahedral seeds with truncated corners,a reduction rate(and thus deposition rate)faster than that of surface diffusion(i.e.,V_(deposition)/V_(diffusion)>1)led to the formation of concave trisoctahedra(TOH)with high-index facets.When the reduction was slowed down,in contrast,surface diffusion dominated the growth pathway.In the case of V_(deposition)/V_(diffusion)≈1,truncated octahedra with enlarged sizes were produced.When the reduction rate was between these two extremes,we obtained concave tetrahexahedra(THH)without or with truncation.Similar growth patterns were also observed for the cuboctahedral seeds.When the Pd octahedra,concave TOH,and concave THH were tested for electrocatalyzing the formic acid oxidation(FAO)reaction,those with high-index facets were advantageous over the conventional Pd octahedra enclosed by{111}facets.This work not only contributes to the understanding of surface diffusion and its role in nanocrystal growth but also offers a general protocol for the synthesis of nanocrystals enclosed by high-index facets.

Analysis of the Oldest Carbonate Gas Reservoir in China——New Geological Significance of the Dengying Gas Reservoir in the Weiyuan Structure, Sichuan Basin

The Weiyuan Structure is the largest surface structure in the Sichuan Basin. However, the abundance of the Dengying Formation gas reservoir in the Weiyuan Structure is low. The height of the gas column is 244 m, but the integrated abundance is only 26.4%. After nearly 40 years of exploration, the Gaoshi1 Well and Moxi8 Well yielded gas flows that marked an important exploration success after the discovery of the Sinian Dengying Formation gas reservoir in the Weiyuan Structure, Sichuan Basin, Lower-Paleozoic in 1964. Combined with research examples of oil and gas migration and gas chimneys around the world, the authors used comprehensive geological-geophysical-geochemical research methods to provide a reasonable explanation of the low abundance of the gas reservoir in the Weiyuan Structure based on the surface and subsurface data. The latest research results show that(1) currently, the Weiyuan Structure is the apex of the Dengying Formation in the Mid-Sichuan Basin. The Guang'an, Longnüsi, Gaoshiti-Moxi, and Weiyuan structures are a series of traps in the Dengying Formation with gradual uplifting spill and closure points during the regional uplift of the Himalayan period. The natural gas of the Dengying Formation accumulated in different ways over a wide range and long distance in the Sichuan Basin.(2) At approximately 40 Ma, the Weiyuan area started to uplift and form the present structure, and it is the only outcropped area with the Triassic Jialingjiang Formation and Leikoupo Formation in the surface of the Sichuan Basin(except the steep structural belt in East Sichuan). Caused by the uplift and denudation, the core of the Weiyuan Structure has formed an escaping "skylight" for natural gas. The evidence of a gas chimney includes(1) the component percentage of non-hydrocarbon gas, which decreased from the bottom to the top,(2) the pressure coefficient is normal because the gas reservoir from the Upper Sinian to the Lower Permian commonly have a normal pressure coefficient(an average of 1.0), and(3) the isotope geochemistry of the argon mostly represents abiogenic characteristics of a deep source, and the 40 Ar/36 Ar ratio is as high as 2 855–5 222 in the Upper Permian. All of these characteristics provide sufficient evidence for a gas chimney effect. The characteristics of low abundance in the Weiyuan Structure can be a reference example for studying the late reconstruction of deep oil and gas reservoirs in the superimposed basins of western China.

Dual-comb spectroscopy resolved three-degreeof-freedom sensing

Precise and fast determination of position and orientation, which is normally achieved by distance and angle measurements, has broad applications in academia and industry. We propose a dynamic three-degree-of-freedom measurement technique based on dual-comb interferometry and a self-designed grating-corner-cube(GCC) combined sensor. Benefiting from its unique combination of diffraction and reflection characteristics, the absolute distance, pitch, and yaw of the GCC sensor can be determined simultaneously by resolving the phase spectra of the corresponding diffracted beams. We experimentally demonstrate that the method exhibits a ranging precision(Allan deviation) of 13.7 nm and an angular precision of 0.088 arcsec, alongside a 1 ms reaction time. The proposed technique is capable of precise and fast measurement of distances and two-dimensional angles over long stand-off distances. A system with such an overall performance may be potentially applied to space missions,including in tight formation-flying satellites, for spacecraft rendezvous and docking, and for antenna measurement as well as the precise manufacture of components including lithography machines and aircraftmanufacturing devices.

Regulating closed pore structure enables significantly improved sodium storage for hard carbon pyrolyzing at relatively low temperature

The closed pore has been considered as the key structure for Na ion storage in hard carbon.However,the traditional view is that closed pores can only be formed by the curling of graphite-like crystallites in the case of high temperature carbonization.Ingenious designing of closed pore structures at lower temperature is still blank.Herein,for the first time,engineering the wall thickness and number of closed pores in waste rosewood-derived hard carbon was successfully achieved at a low temperature of 1100℃ by removing the lignin and hemicellulose components in wood precursor.When applied as an anode material,the optimum sample exhibits a high capacity of 326 mAh/g at 20 mA/g and a remarkable rate capability of 230mAh/g at 5000 mA/g,significantly higher than those of the untreated sample(only 33 mAh/g at 5000 mA/g).The significantly improved Na storage performance should be attributed to abundant closed pores that provide sufficient spaces forNa storage and thin porewall structure that is beneficial to the diffusion of Na^(+)in the bulk phase.This work provides a new idea for the future application of biomass-based hard carbon for advanced Na ion batteries.

Review of the Formation Mechanisms and Control Methods of Geometrical Defects in Laser Deposition Manufacturing

Laser deposition manufacturing(LDM)is a revolutionary integrated manufacturing technology that expands numerous possibilities for producing large-scale parts in the aerospace and other industries.However,geometrical defects can severely affect the forming accuracy of parts and restrict the progress of LDM technology to large-scale components.This study summarizes the main types of geometrical defects and classifies them into four categories:flatness defects,melting collapse,distortion,cracking,and delamination.To overcome this challenge,one approach that has received considerable attention is process monitoring accompanied by mitigation strategies to improve the forming accuracy and repeatability.This study outlines the current understanding of the formation mechanism of common geometrical defects and discusses techniques to monitor the process and mitigate defects.Further,it discusses approaches for monitoring and controlling the LDM process while emphasizing the monitored melt pool,surface topography,temperature,and distortion.Next,the study focuses on procedures,including optimizing process parameters,thermal control methods,prediction,and compensation,to mitigate geometrical defects.Finally,the aim of the study is to provide a reference for researchers in this field.However,many future research hotpots for LDM precision control that require further investigation are still present.