A Hybrid Genetic Algorithm for the Traveling Salesman Problem with Pickup and Delivery

In this paper, a hybrid genetic algorithm （GA） is proposed for the traveling salesman problem （TSP） with pickup and delivery （TSPPD）. In our algorithm, a novel pheromone-based crossover operator is advanced that utilizes both local and global information to construct offspring. In addition, a local search procedure is integrated into the GA to accelerate convergence. The proposed GA has been tested on benchmark instances, and the computational results show that it gives better convergence than existing heuristics.

Corrosion-wear behavior of nanocrystalline Fe88Si12 alloy in acid and alkaline solutions

The corrosion-wear behavior of a nanocrystalline Fe_（88）Si_（12） alloy disc coupled with a Si_3N_4 ball was investigated in acid（pH 3） and alkaline（pH 9） aqueous solutions. The dry wear was also measured for reference. The average friction coefficient of Fe_（88）Si_（12） alloy in the pH 9 solution was approximately 0.2, which was lower than those observed for Fe_（88）Si_（12） alloy in the pH 3 solution and in the case of dry wear. The fluctuation of the friction coefficient of samples subjected to the pH 9 solution also showed similar characteristics. The wear rate in the pH 9 solution slightly increased with increasing applied load. The wear rate was approximately one order of magnitude less than that in the pH 3 solution and was far lower than that in the case of dry wear, especially at high applied load. The wear traces of Fe_（88）Si_（12） alloy under different wear conditions were examined and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The results indicated that the tribo-chemical reactions that involve oxidation of the worn surface and hydrolysis of the Si_3N_4 ball in the acid solution were restricted in the pH 9 aqueous solution. Thus, water lubrication can effectively improve the wear resistance of nanocrystalline Fe_（88）Si_（12） alloy in the pH 9 aqueous solution.

A strange star scenario for the formation of eccentric millisecond pulsar PSR J1946+3417

PSR J1946+3417 is a millisecond pulsar(MSP)with a spin period P?3.17 ms.Harbored in a binary with an orbital period Pb?27 days,the MSP is accompanied by a white dwarf(WD).The masses of the MSP and the WD were determined to be 1.83 M⊙,and 0.266 M⊙,respectively.Specially,its orbital eccentricity is e?0.134,which is challenging the recycling model of MSPs.Assuming that the neutron star in a binary may collapse to a strange star when its mass reaches a critical limit,we propose a phase transition(PT)scenario to account for the origin of the system.The sudden mass loss and the kick induced by asymmetric collapse during the PT may result in the orbital eccentricity.If the PT event takes place after the mass transfer ceases,the eccentric orbit cannot be re-circularized in the Hubble time.Aiming at the masses of both components,we simulate the evolution of the progenitor of PSR J1946+3417 via MESA.The simulations show that an NS/main sequence star binary with initial masses of 1.4+1.6 M⊙in an initial orbit of 2.59 days will evolve into a binary consisting of a 2.0 M⊙MSP and a 0.27 M⊙WD in an orbit of~21.5 days.Assuming that the gravitational mass loss fraction during PT is 10%,we simulate the effect of PT via the kick program of BSE with a velocity ofσPT=60 km s-1.The results show that the PT scenario can reproduce the observed orbital period and eccentricity with higher probability than other values.

Silencing of transcription factor E93 inhibits adult morphogenesis and disrupts cuticle, wing and ovary development in Locusta migratoria

Ecdysone-induced protein 93F(E93)plays important roles during the metamorphosis process in insects.In this study,a cDNA of the LmE93 gene was identified from the transcriptome of Locusta migratoria,which consists of the 3378-nucleotide open-reading frame(ORF)and encodes 1125 amino acids with helix–turn–helix(HTH)motifs.Reverse transcription quantitative polymerase chain reaction analysis revealed that LmE93 was highest expressed in ovary.The LmE93 expression level was markedly low from the 3rd to 4th instar nymphs,and greatly increased in 1-day-old 5th instar nymphs with a peak on middle nymphal days,then declined in the late nymphal days.Moreover,injected dsLmE93 into 4th and 5th instar nymphs greatly reduced LmE93 transcripts,respectively,and prevented the process of metamorphosis,causing supernumerary nymphal stages.Hematoxylin–eosin staining of the integument showed that the apolysis occurred in advance in 4th instar nymphs,and old cuticle degradation was decreased in dsLmE93-injected locusts of 5th instar nymphs.Smaller and no fully developed wings with reduced columns between the anterior and posterior regions were found in N6 and N7 supernumerary nymphs.In addition,the development of the ovary in dsLmE93-injected locusts was severely blocked,the yolk was almost not formed and there was no development of ovarioles.The results indicated that LmE93 play key roles in the metamorphosis,cuticle,wing and ovarian development of locusts.

Compressive Tracking Based on Online Hough Forest

Existing tracking algorithms often suffer from the drift and lost problems caused by factors such as pose variation, illumination change, occlusion and motion. Therefore, developing a robust and effective tracker is still a challenging task. In this paper, we propose a real-time compressive tracking based on online Hough forest. The gray and texture features of discrete samples are extracted and compressed via the random measurement matrix. Online Hough forest classifier is used to vote the location probability of the target, and it optimizes the confidence map estimation for the target detection. The location of target being tracked is determined by combining the upper frame of the target center location and the probability confidence map of the incremental Hough forest. Finally, the classifier parameters are updated online by introducing the illumination variation and target occlusion feedback mechanism adaptively. The experiments with state-of-the-art algorithms on challenging sequences demonstrated that the proposed algorithm can effectively enhance the robustness and accuracy, and inherit the real-time performance of the compressive tracking algorithm.

Dry-sliding tribological properties of AlCoCrFeNiTi_(0.5)high-entropy alloy

High-entropy alloys(HEAs),with a new alloying concept,could possess many unique mechanical and functional properties.The current work investigated whether one such alloy offers potential for bearing surfaces under dry conditions.The dry,reciprocating sliding wear characteristics of AlCoCrFeNiTi0.5alloy were investigated under various applied loads and sliding speeds.Transmission electron microscopy(TEM) and scanning electron microscopy(SEM) were utilized to characterize internal structure and wear surfaces of the alloy,respectively.It is found that the AlCoCrFeNiTi0.5alloy preserves better wear resistance than Fe77Ni23solid solution alloy,Ti-46Al-2Cr-2Nb intermetallic alloy,or a wear-resistant steel AISI52100,especially under higher loads.The wear rate increases slowly with the applied loads increasing and keeps steady under different sliding speeds.The wear mechanisms are abrasive wear,adhesive wear and oxidative wear.The nano-sized Fe-Cr solid solution and Al-NiTi rich intermetallic phase precipitated in the dendritic regions and the formation of oxidation play important roles in the good wear resistances of this high-entropy alloy.

Lmlntegrinβ-PS is required for wing morphogenesis and development in Locusta migratoria

Wings are an important flight organ of insects and their morphogenesis depends on a series of cell-to-cell and cell-to-extracellular matrix interactions.Integrin as a transmembrane protein receptor mediates cell-to-cell adhesion,cell-to-extracellular matrix interactions and signal transduction.In the present study,we characterized an integrin gene that encodes integrinβ-PS protein in Locusta migratoria.Lmlntegrinβ-PS is highly expressed in the wing pads and the middle stages of 5th instar nymphs.Immunohisto-chemical analysis revealed that the Lmlntegrinβ-PS protein was localized at the cell base of the two layers of wings.After suppression of Lmlntegrinβ-PS by RNA interference,the wing pads or wings were unable to form normally,with a blister wing appearance during nymph to nymph transition and nymph to adult transition.We further found that the dorsal and ventral epidermis of the wings after dsLmlntegrinβ-PS injection were improperly connected and formed huge cavities revealed by hematoxylin and eosin staining.Furthermore,the morphology and structure of the wing cuticle was significantly disturbed which affected the stable arrangement and attachments of the wing epidermis.Moreover,the expression of related cell adhesion genes was significantly decreased in LmIntegrinβ-PS-suppressed L.migratoria,suggesting that Lmlntegrinβ-PS is required for the morphogenesis and development of wings during molting by stabilizing cell adhesion and maintaining the cytoskeleton of these cells.

Tribological properties of plasma-sprayed nickel alloy matrix self-lubricating coating at elevated temperatures

A nickel alloy matrix high-temperature self-lubricating coating(77.5 wt%(Ni-Cr-Mo-Al)-12.5 wt%Ag-10 wt%BaF2/CaF2)was prepared by plasma spraying technique.Results show that the Vickers microhardness of coating is(2.9±0.5)GPa,and the average bonding strength is about(35.6±0.5)MPa.The coating rubbing against Inconel 718 superalloy pin exhibits superior tribological performance with coefficient of friction(COF)of below 0.25 and wear rate of 8.2×10^(-5)-15.2×10^(-5)mm^(3)·N^(-1)·m^(-1)at a wide temperature range from 25 to 800℃,and the COF and the wear rate are slightly reduced with temperature increasing.The low COF and wear rate were attributed to the synergistic effects of Ag,BaF_(2)/CaF_(2),Ag2MoO_(4)and BaMoO_(4).

Roles of LmCDA1 and LmCDA2 in cuticle formation in the foregut and hindgut of Locusta migratoria

Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular intima of the foregut and hindgut are unclear.Here,we investigated the roles of their respective genes LmCDAI and Lm-CD42 in this process,in the hemimetabolous insect Locusta migratoria.Transcripts of LmCDAI and LmCDA2 were highly expressed both before and after molting in the foregut.In the hindgut,their expression was high only before molting.In both the foregut and hindgut,LmCDA1 protein was localized in the basal half of the chitin matrix(procuti-cle),whereas LmCDA2 was detected in the upper half of the procuticle.K nockdown of LmCDAI by RNA interference(RNAi)in 5th-instar nymphs caused no visible defcts of the hindgut cuticle.By contrast,the chitinous lamellae of the cuticular intima in the foregut of knockdown animals were less compact than in control animals.RNAi against LmCDA2 led to thickening of both the foregut and hindgut cuticles,with a greater number of thinner laminae than in the respective control cuticles.Taken together,our results show that LmCDAI and LmCDA2 have distinct,but overlapping,functions in chitin organization in the foregut cuticle.However,in the hindgut,this process seems independent of LmCDA1 activity but requires LmCDA2 function.Thus,the CDAs reflect tissue-specific differences in cuticular organization and function,which need further detailed molecular and histological analyses for full comprehension.

Porphyrin-based Nanosonosensitizers Combined with Targeting Peptides for Sonodynamic Therapy of Glioma

Traditional cancer treatments have disadvantages of large trauma area and toxic side effects while killing cancer cells.Peptide-targeted sonodynamic therapy(SDT)can effectively improve specificity of cancer treatment and overcome the problem of low tissue penetration depth caused by a photo-driven therapy.Herein,we developed a porphyrin-based sonosensitizer with a water-soluble polymer as a biological carrier and a cRGD peptide for tumor targeting,which constituted a nano sonosensitizer(T-cRGD NPs)for fluorescence imaging-guided sonodynamic therapy.A comparable sonosensitizer(T-PEG NPs)without the targeting unit was also prepared for illustration of therapeutic performance.Attribute to the role of peptide targeting,T-cRGD NPs can accumulate and enter tumor cells for fluorescence imaging and show a superior SDT effect than T-PEG NPs in vitro.The imaging in vivo reveals that T-cRGD NPs can enrich in tumor tissues within 14 h with a good biocompatibility.