Search

This paper presents an experimental study on the effects of lateral tension and loading rate on the local bond performance of ribbed bars in concrete. The results show that, up to a loading rate of 10 mm/s, the mode of bond failure is independent of the loading rate but is closely related to the cover depth, concrete grade and level of lateral tension. It is also shown that the bond strength of ribbed bars increases with the increase of loading rate but decreases with an increase in lateral tension. The increase or decrease ratio becomes larger when splitting failure occurs. Specifically, for pull-out and splitting failure, the bond strength decreases by 8% and 22% when the lateral tension increases from 0.0 to 0.6 times the tensile strength of concrete but increases by 22% and 28% when the loading rate increases from 0.01 to 10 mm/s, respectively. The slip at peak bond stress is rate-insensitive. It can be taken as 0.18 times the rib spacing for pull-out failure but decreases linearly with the increase of lateral tension for splitting failure. Finally, a bond stress–slip model with three parameters is suggested for different levels of lateral tension and loading rates.

Based on the extended hadronic transport model of relativistic heavy-ion collisions, the incompressibility of dense hadronic matter created in relativistic Au+Au heavy-ion collisions at $\sqrt{s_{NN}} = 3$ GeV is studied. By comparing experimental proton directed flow, productions of strange hadrons $\phi$, $K^{-}$ as well as their ratio $\phi/K^{-}$, proton high-order cumulants to the model calculations, a large incompressibility of dense hadronic matter is obtained from nucleon observabels while a rather small incompressibility is needed to fit the data of strange hadrons. This may indicate hadronic matter possesses different incompressibilities in different density regions, i.e., the incompressibility may become stiffer from saturation density to a certain baryon density and then turn to soft before reaching hadron-quark phase transition. The study also shows that the incompressibility significantly affects the critical baryon density of hadron-quark phase transition., Comment: 5 pages, 4 figures, accepted by PRC, in production

OBJECTIVE: To study the clinical features and prognosis of children and their family members with family clusters of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection under the admission mode of parent-child ward. METHODS: A retrospective analysis was performed on the medical data of 190 children and 190 family members with SARS-CoV-2 Omicron variant infection who were admitted to Shanghai Sixth People's Hospital, the designated hospital for coronavirus disease 2019 (COVID-19), April 8 to May 10, 2022. RESULTS: Both the child and adult groups were mainly mild COVID-19, and the proportion of mild cases in the child group was higher than that in the adult group (P

Cyclocarya paliurus (CP) extracts have been shown to lower sugar and lipid levels in blood, but the material basis is not clear. We analyzed CP aqueous extracts using high-performance liquid chromatography "fingerprinting", checked their pharmacological parameters using virtual screening, and undertook molecular docking and molecular dynamics simulations. Also, the inhibitory effects of CP components upon α-glucosidase in vitro were evaluated. Fingerprinting and virtual screening showed that the aqueous extract of CP contained the active components protocatechuic acid, chlorogenic acid, caffeic acid and rutin, which were safe and had no side effects in vivo. Molecular docking and molecular dynamics simulations showed that chlorogenic acid and rutin might have a potent inhibitory effect on α-glucosidase. An enzyme-activity assay in vitro showed that the half-maximal inhibitory values of chlorogenic acid and rutin were 398.9 and 351.8 μg/ml, respectively. Chlorogenic acid and rutin had an inhibitory effect on α-glucosidase. Cyclocarya paliurus could be developed as a natural α-glucosidase inhibitor.

Poria cocos is a traditional Chinese medicine (TCM) that can clear dampness, promote diuresis, and strengthen the spleen and stomach. Poria cocos has been detected in many TCM compounds that are used for COVID-19 intervention. However, the active ingredients and mechanisms associated with the effect of Poria cocos on COVID-19 remain unclear. In this paper, the active ingredients of Poria cocos, along with their potential targets related to COVID-19, were screened using TCMSP, GeneCards, and other databases, by means of network pharmacology. We then investigated the active components, potential targets, and interactions, that are associated with COVID-19 intervention. The primary protease of COVID-19, Mpro, is currently a key target in the design of potential inhibitors. Molecular docking techniques and molecular dynamics simulations demonstrated that the active components of Poria cocos could bind stably to the active site of Mpro with high levels of binding activity. Pachymic acid is based on a triterpene structure and was identified as the main component of Poria cocos; its triterpene active component has low binding energy with Mpro. The pachymic acid of Mpro activity was further characterized and the IC50 was determined to be 18.607 μmol L−1. Our results indicate that pachymic acid exhibits a certain inhibitory effect on the Mpro protease.

Antifungalmycin N2 (3-methyl-3,5-amino-4-vinyl-2-pyrone, C6H7O2N) was a novel metabolite produced from Streptomyces sp. strain N2, and the present study aimed to evaluate its antibacterial and cytotoxic properties. By using Oxford cup method, the obtained results revealed that antifungalmycin N2 exhibited a significant antibacterial activity against the pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, and Micrococcus kristinae, especially the Gram-positive S. aureus. Meanwhile, the MTT assay showed that antifungalmycin N2 could exert a marked inhibitory action on tumor cell lines, such as the cell lines of BEL-7402 (human hepatocellular carcinoma), Hela (human cervical carcinoma), HCT116 (human colon cancer), and SW620 (human colon cancer). And the IC50 values antifungalmycin N2 against the above cell lines ranged from 11.23 to 15.37 μg/mL. In conclusion, the antibacterial and cytotoxic activities suggested that the novel antifungalmycin N2 was a promising active structure to be developed as new drug for treating infectious diseases and cancers.

Cervical cancer is one of the leading causes of cancer-associated mortality among females; however, the underlying molecular mechanisms of its carcinogenesis remain largely unclear. Previous comprehensive genomic studies have revealed prevalent estrogen receptor 1 (ESR1) mutations in breast cancer, which are rare in certain other types of cancer. To the best of our knowledge, it is unknown whether ESR1 mutations also exist in cervical cancer. Considering the evidence that cervical cancer shares certain genetic aberrations with breast cancer, and that the progression of both breast and cervical cancers can be affected by estrogen, it is possible that cervical cancer may also harbor ESR1 mutations. In the present study, a total of 260 Chinese cervical cancer samples with distinct subtypes were tested for the presence of ESR1 mutations. A total of three heterozygous missense ESR1 mutations, p.K303R (c.908A>G), p.T311M (c.932C>T) and p.Y537C (c.1610A>G), were identified in 3/207 (1.4%) cervical squamous cell carcinoma samples, which were absent in 27 adenosquamous carcinomas and 26 adenocarcinomas samples. Of the three individuals with an ESR1mutation, 1 patient was also diagnosed with ovarian endometriosis and the other 2 patients were diagnosed with a uterine fibroid. A bioinformatics analysis suggested that these ESR1 mutations may be pathogenic by promoting the development of cervical cancer. Furthermore, a previous comprehensive study confirmed that individuals with cervical squamous cell carcinoma possessed ESR1 mutations. These combined studies indicate that ESR1 mutations may participate in the carcinogenesis of cervical squamous cell carcinoma, albeit at a low frequency. In conclusion, the present study identified three potentially pathogenic ESR1 mutations in Chinese cervical squamous cell carcinoma samples, but not in other subtypes.

Liupao tea, a drink homologous to medicine and food. It can treat dysentery, relieve heat, remove dampness, and regulate the intestines and stomach. The objective of this study is to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. We used high performance liquid chromatography to analyze the extract of Liupao tea and establish its fingerprint. The main index components of the fingerprint were determined using SARS-COV-2 3-chymotrypsin-like protease (3CLpro ), and an in vitro drug screening model based on fluorescence resonance energy transfer was used to evaluate its inhibitory activity in vitro. The fingerprint results showed that the alcohol extract of Liupao tea contained gallic acid, epigallocatechin gallate (EGCG), caffeine, epicatechin gallate, rutin, and ellagic acid. The molecular docking binding energies of the six index components of SARS-CoV-2 3Clpro were all less than -5.0 kJ/mol and showed strong binding affinity. The results of in vitro activity showed that the IC50 of EGCG was 8.84 µmol/L, which could inhibit SARS-CoV-2 3Clpro to a certain extent. This study unleashed that EGCG has a certain inhibitory effect on SARS-CoV-2 3CLpro , and Liupao tea has a certain significance as a tea drink for the prevention of COVID-19. PRACTICAL APPLICATIONS: The objective of this study was to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. The molecular docking binding energies of the six index components of Liupao tea with SARS-CoV-2 3CLpro were all less than -5.0 kJ/mol, among them, the enzyme activity experiment shows that EGCG has a certain inhibitory effect on SARS-CoV-2 3CLpro , it can be used as a potential SARS-CoV-2 3CLpro inhibitor. We predicted that the understandings gained in the current research may evidence that Liupao tea has a certain significance as a tea drink for the prevention of COVID-19.

Liupao tea, a drink homologous to medicine and food. It can treat dysentery, relieve heat, remove dampness, and regulate the intestines and stomach. The objective of this study is to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. We used high performance liquid chromatography to analyze the extract of Liupao tea and establish its fingerprint. The main index components of the fingerprint were determined using SARS-COV-2 3-chymotrypsin-like protease (3CL

The parameter γ∗ we previously defined has been proved to be valid in predicting the better glass former in several binary alloy systems, but is hard to be applied in the multi-component alloys because the phase diagrams of these alloys are usually not well constructed. In the present work, we attempt to extend the application of parameter γ∗ to a ternary alloy system and predict the better glass former in the Ni62Nb38-xTax (x = 5, 10, 15, 20, 25, 30, 35) alloys based on the systematic investigation on the phase evolution from Ni62Nb38 to Ni62Ta38. The prediction has been confirmed by the experimental results, indicating the validity of the parameter γ∗ in the Ni62(Nb, Ta)38 ternary alloys.

Antifungalmycin N2 (3-methyl-3,5-amino-4-vinyl-2-pyrone, C

The development of intelligent oral drug delivery carrier aiming at efficiently bring insulin to intestine is of great significance for diabetes mellitus therapy. In the present study, a series of amphiphilic pH-sensitive block copolymer poly(methyl methacrylate-co-methacrylicacid)-b-poly(2-amino ethyl methacrylate) [P(MMA-co-MAA)-b-PAEMA] was synthesized via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and further self-assembled into pH-responsive cationic polymeric micelles (PCPMs) for oral insulin delivery. The structure and molecular weight were confirmed by proton nuclear magnetic resonance (1H-NMR), Fourier transforming infrared spectrum (FT-IR) and gel permeation chromatography (GPC), respectively. The critical micelle concentration (CMC) values of these copolymers were measured by fluorescent probe method at pH 1.2 (8–15 μg/mL) and pH 7.4 (22–42 μg/mL), respectively, demonstrating high stability at acidic environment. A decrease in the particle size of PCPMs was associated with an increased pH at beginning, which reached around 200 nm at neutral pH, while the particle size increased obviously with pH increase, indicating the pH-sensitivity of PCPMs. The insulin was entrapped into the core of PCPMs (Ins-loaded PCPMs) with high loading efficiency via diafiltration method. The in vitro experiments show Ins-loaded PCPMs have low toxicity and exhibit pH-triggered release profile with remitted initial burst release. The results indicate that the PCPMs self-assembled from P(MMA-co-MAA)-b-PAEMA may be potential carriers for efficient oral delivery of insulin with controlled release property.

The frustrated spin-1/2 J1a–J1b–J2 antiferromagnet with anisotropy on the two-dimensional square lattice was investigated, where the parameters J1a and J1b represent the nearest neighbor exchanges and along the x and y directions, respectively. J2 represents the next-nearest neighbor exchange. The anisotropy includes the spatial and exchange anisotropies. Using the double-time Green’s function method, the effects of the interplay of exchanges and anisotropy on the possible phase transition of the Neel state and stripe state were discussed. Our results indicated that, in the case of anisotropic parameter 0 ≤ η ≤ 1, the Neel and stripe states can exist and have the same critical temperature as long as J2 = J1b/2. Under such parameters, a first-order phase transformation between the Neel and stripe states can occur below the critical point. For J2 ≠ J1b/2, our results indicate that the Neel and stripe states can also exist, while their critical temperatures differ. When J2 > J1b/2, a first-order phase transformation between the two states may also occur. However, for J2 < J1b/2, the Neel state is always more stable than the stripe state.

The melting and crystallization with two different cooling rates of large sized CuN (N = 1956, 2112, 2208, and 2340) nanoclusters are simulated by using molecular dynamics technique with the frame work of embedded atom method. The potential energy as a function of temperatures is obtained and the structural details are analyzed. The results reveal that the melting and freezing temperatures increase almost linearly with the atom number of the clusters slowly. All the copper nanoclusters have negative heat capacity around the phase transition temperature, and the clusters with slow cooling rates have icosahedral structure at 300 K.

A Pb(II)-based coordination polymer, namely Pb-BSDC, has been synthesized by the reaction of 2,2′-bis(sulfomethyl)-[1,1′-biphenyl]-4,4′-dicarboxylic acid (H4BSDC) and lead nitrate through solvothermal self-assembly strategy. With the protophilic sulfonic groups and hydrogen-bonding interactions, Pb-BSDC exhibits efficient water-assisted proton conduction. Importantly, single-crystal Pb-BSDC shows a high proton conductivity of 1.71 ​× ​10-2 ​S ​m-1 at 90 ​°C and 85% RH (relative humidity), suggesting a promising candidate for proton-conductor. Further mechanism investigation indicates that proton conduction in bulk sample of Pb-BSDC follows the Vehicle mechanism (Ea ​= ​0.63 ​eV) while single-crystal state follows the Grotthuss mechanism (Ea ​= ​0.35 ​eV). In addition, the luminescent property of Pb-BSDC was also studied and it showed a broad band emission with the maximum at 502 ​nm under the irradiation of 310 ​nm UV light.

The compatibility of an amphiphilic pH-sensitive polymer (docosahexaenoic acid–histidine–lysine, DHA–HisXLys10) and hydrophobic drug (doxorubicin, DOX) was investigated using multiscale simulations at different pH conditions, including Blends and dissipative particle dynamics simulations. Some important elements obtained from the computer simulations were analyzed, such as Flory–Huggins interaction parameters, binding energy distributions, phase diagrams and radius distribution function. In conclusion, the pH values and the number of pH-sensitive segments (histidine) significantly influence the compatibility of DHA–HisXLys10 and DOX, resulting in different drug loading capacity and system structural stability. According to the simulation results, the compatibility of the systems at pH > 6.0 is better than that at pH 6.0. Using DPD simulation, the compatibility of DHA–HisXLys10 (X = 10 or 15) and DOX is optimal when the pH is higher than 6.0, which falls in line with the results obtained from Blends simulation. Overall, when the number of histidine residues is 10 or 15 and the pH is larger than 6.0, DOX and DHA–HisXLys10 have better compatibility. So it is obvious that polymeric micelles self-assembled from DHA–His10Lys10/DHA–His15Lys10 as an ideal drug carrier have higher drug-loading capacity and more excellent stability. This work has demonstrated that multiscale simulations could be a powerful method to investigate the compatibility between polymers and drugs.

In this work, the formation of polymeric micelles as drug delivery vehicles in an aqueous environment is investigated by dissipative particle dynamics (DPD) simulations. Doxorubicin (DOX) is selected as the model drug, whereas docosahexaenoic acid (DHA) conjugated His10Lys10 (DHA-His10Lys10) as the drug carrier. It is shown from DPD simulation that drug molecules and DHA-His10Lys10 molecules could aggregate and form micelles under a defined composition recipe; drug molecules are homogeneously distributed inside the carrier matrix, on whose surface the stabilizer lysine segments are absorbed. Under different compositions of drug and water, aggregate morphologies of polymeric micelles are observed as spherical, columnar, and lamellar structures. We finally proposed the formation mechanism of drug loaded polymeric micelles and apply it in practice by analyzing the simulated phenomena. All the results can effectively guide the experimental preparation of drug delivery system with desired properties or explore a novel polymeric micelle with high performance.

The microstructures of doxorubicin-loaded micelles prepared from block polymers His(x)Lys10 (x = 0, 5, 10) conjugated with docosahexaenoic acid (DHA) are investigated under different pH conditions, using dissipative particle dynamics (DPD) simulations. The conformation of micelles and the DOX distributions in micelles were obviously influenced by pH values and the length of the histidine segment. At pH6.0, the micelles self-assembled from the polymers were dense and compact. The drugs were entrapped well within the micellar core. The particle size increases as the histidine length increases. With the decrease of pH value to be lower than 6.0, there was no distinct difference for the micelles self-assembled from the polymer without histidine residues. However, the micelles prepared from the polymers with histidine residues shows a structural transformation from dense to swollen conformation, leading to an increased particle size from 10.3 to 14.5 DPD units for DHD-His10Lys10 micelles. This structural transformation of micelles can accelerate the DOX release from micelles under lower pH conditions. The in vitro drug release from micelles is accelerated by the decrease of pH value from 7.4 (physiological environment) to 5.0 (lysosomal environment). The integration of simulation and experiments might be a valuable method for the optimization and design of biomaterials for drug delivery with desired properties.

The two-dimensional doped mixed-spin anisotropic ferromagnets is investigated by means of the double-time Green׳s function based on the random phase approximation and Anderson–Callen׳s decoupling approximation. The analytic expressions of the critical temperature and the high-temperature zero-field susceptibility are obtained. The phase diagrams in which the critical temperature, the reorientation temperature and the reorientation magnetic field are shown as a function of single-ion anisotropic parameter are discussed.

Chimera states consisting of spatially coherent and incoherent domains have been observed in different topologies such as rings, spheres, and complex networks. In this paper, we investigate bipartite networks of nonlocally coupled FitzHugh–Nagumo (FHN) oscillators in which the units are allocated evenly to two layers, and FHN units interact with each other only when they are in different layers. We report the existence of chimera states in bipartite networks. Owing to the interplay between chimera states in the two layers, many types of chimera states such as in-phase chimera states, antiphase chimera states, and out-of-phase chimera states are classified. Stability diagrams of several typical chimera states in the coupling strength–coupling radius plane, which show strong multistability of chimera states, are explored.

The composition and working principles of the constructed Hybrid Electric Vehicle’s Electronic Throttle Control System are introduced. This paper presents the control strategy, and implements the Electronic Throttle Control System based on Fuzzy PID algorithm. It analyzes the resolution, react characteristics and dynamic tracking performance of the control system, and also discusses the anti-jamming measures under the automotive complex operation condition. The real vehicle test results demonstrate that this electronic throttle control system features better tracking and robustness.

The efficient hydroxyalkylation of phenol with formaldehyde to bisphenol F over a thermoregulated phase-separable reaction system containing a water-soluble Bronsted acidic ionic liquid was studied. The reaction system containing the water-soluble IL showed thermoregulated biphasic behavior with change of the alkyl chain length of IL, temperature and water amount. Four types of imidazolium-, ammonium-, phosphonium- and pyridinium-based water-soluble ionic liquids with different anions of dihydrogen phosphate [H2PO4]−, acetate [CH3COO]− and hydrogen sulfate [HSO4]− were used as both Bronsted acidic catalysts and thermoregulated solvents. Among them, [C6MIM][HSO4] gave a high yield of 80.5% and a selectivity of 96.9% for bisphenol F, and the optimal reaction conditions were stirring speed 450 rpm, phenol–formaldehyde ratio 6:1, IL catalyst molar concentration 12.5%, reaction temperature 90 °C and reaction time 1 h. [C6MIM][HSO4] could be recovered by simple decantation and could retain its original activity even after six recycling-uses [CnMIM][HSO4] with the alkyl chain length n = 6 found to be the most suitable for the synthesis of bisphenol F because of both the formation of a thermoregulated monophasic reaction system at 90 °C to enhance the reaction efficiency and as a thermoregulated phase-transition solvent to facilitate its recovery from the reaction system.

Several experimental investigations were conducted on the autogenous shrinkage and creep performances of two types of designed self-compacting lightweight concrete (SCLC). In order to explore the difference in long-term performance between SCLC and normal aggregate concrete, normal aggregate self-compacting concrete (SCC) and normal concrete (NC) are also designed in this study. The results indicate that the designed SCLC exhibits lower autogenous shrinkage at early age, even slight expansion during the first 10 days. After 6 months, the autogenous shrinkage of SCLC increases nearly equal to those of normal aggregate concrete. Compared with the reference concretes NC and SCC, the 360-day creep coefficient of SCLC is lower, but the specific creep is higher. It is also found that long-term creep coefficient and specific creep decrease with the increase of compressive strength of SCLC.

Aqueous solutions of N-methyldiethanolamine (MDEA) are widely used in the sweetening process of sour gases, but the solutions deteriorate due to the contamination in their use process, and the deficiencies of the technologies for the regeneration of disabled solution restrict their development. A vacuum membrane distillation (VMD) technique for the regeneration of MDEA solutions was proposed and experimentally investigated.It is studied the effect of change in solution temperature on its regeneration efficiency and the distillation flux. From the chromatograms it is known that the best temperature for regenerating waste solution by VMD is 70 °C,and the regeneration efficiency can be up to 98% at this experimental conditions.

The pH-sensitive nanoparticles are selected as the potentially promising oral protein and peptide drug carriers due to their excellent performance. With the poly (lactic-co-glycolic acid)/hydroxypropyl methylcellulose phthalate (PLGA/HP55) nanoparticle as a model nanoparticle, the structure-property relationship of nanoparticles with different conditions is investigated by dissipative particle dynamics (DPD) simulations in our work. In the oral drug delivery system, the poly (lactic-co-glycolic acid) (PLGA) is hydrophobic polymer, hydroxypropyl methylcellulose phthalate (HP55) is pH-sensitive enteric polymer which used to protect the nanoparticles through the stomach and polyvinyl alcohol (PVA) is hydrophilic polymer as the stabilizer. It can be seen from DPD simulations that all polymer molecules form spherical core-shell nanoparticles with stabilizer PVA molecules adsorbed on the outer surface of the PLGA/HP55 matrix at certain compositions. The DPD simulation study can provide microscopic insight into the formation and morphological changes of pH-sensitive nanoparticles which is useful for the design of new materials for high-efficacy oral drug delivery.

This study is to determine five naphthaquinones (acetylshikonin, β-acetoxyisovalerylalkannin, isobutylshikonin, β,β'-dimethylacrylalkannin,α-methyl-n-butylshikonin） by quantitative analysis of multi-components with a single marker (QAMS). β,β'-Dimethylacrylalkannin was selected as the internal reference substance, and the relative correlation factors (RCFs) of acetylshikonin, β-acetoxyisovalerylalkannin, isobutylshikonin and α-methyl-n-butylshikonin were calculated. Then the ruggedness of relative correction factors was tested on different instruments and columns. Meanwhile, 16 batches of Arnebia euchroma were analyzed by external standard method (ESM) and QAMS, respectively. The peaks were identifited by LC-MS. The ruggedness of relative correction factors was good. And the analytical results calculated by ESM and QAMS showed no difference. The quantitative method established was feasible and suitable for the quality evaluation of A. euchroma.

Based on European Standard EN441-2, an experiment system for measuring the thermal properties of refrigerated display cabinet is designed and constructed. Considering the practice requirements from user, the air distribution analysis is doing under various air-flow form in the testing room. This paper uses the FLUENT, which is one of the CFD simulation software, to verify the design method of air movement. Finally a series of tests required for laboratory quality regulation have been done and the data of velocity or temperature is under the new requirement.

The melting and crystallization with two different cooling rates of Au N (N = 140, 360, 532, 784, and 952) nanoclusters are simulated by using molecular dynamics technique with the frame work of embedded atom method. The potential energy as a function of temperature is obtained and the structural details are analyzed. The results reveal that the melting and freezing temperature increases almost linearly with the atom number of the clusters. All the gold nanoclusters have negative heat capacity around the phase transition temperature, and the clusters with slow cooling rate have icosahedral structure at 300 K.

The maximum fracture load of a notched concrete beam has been related to the local fracture energy at the cohesive crack tip region analytically in this paper, and then the correlation between the size effects on the maximum fracture loads and the RILEM specific fracture energy is established. Two extreme conditions have been established, namely zero crack-tip bridging with zero local fracture energy and maximum crack-tip bridging with the maximum size-independent fracture energy. It is concluded that the local fracture energy at the crack tip region indeed varies with the initial crack length and the size of specimen. The tri-linear model for the local fracture energy distribution is confirmed by using the proposed simple analytical solution.

This paper presents an experimental investigation on the properties of the fracture process zone (FPZ) in concrete using the digital image correlation (DIC) technique. Based on the experimental results, it is found that the FPZ length increases during crack propagation but decreases after the FPZ is fully developed. The FPZ length at the peak load and the maximum FPZ length increase with an increase in specimen height, but decrease by increasing the notch depth to specimen height ratio. It is also found that the crack extension length at the peak load is about 0.25 times the ligament length.

The use of externally bonded fibre reinforced polymer (EB-FRP) composites is becoming popular for the repair of understrengthened or damaged reinforced concrete members. However, the EB-FRP strengthened members often fail owing to fibre reinforced polymer (FRP) debonding, reducing the strength utilisation ratio of FRP and leading to catastrophic structural failure. To solve the problem, an improved hybrid bonded FRP (IHB-FRP) technique is developed in this paper. The pull-out test was conducted to select an appropriate mechanical fastener for the technique and IHB-FRP strengthened reinforced concrete beams were tested under three-point bending to examine the effectiveness of the technique. Experimental results show that the selected fastener is suitable for the IHB-FRP technique and the IHB-FRP strengthened beam fails owing to FRP rupture even for seven plies of FRP strips. Finally, the required tightening force in the fastener is estimated to ensure the effectiveness of the IHB-FRP technique.

This paper bases on the prototype of the actual shed tunnel structure, study on contact force, displacement, damage, energy of shed tunnel under impact of rock-fall. By ABAQUS finite element software to simulate the process of roll-fall impact knowable: Rock-fall at different speeds and incident angle shocks on shed tunnel has great influence to concrete protective structure of contact force and displacement; Concrete protective structure damage the worst hit area of occurred with roll-fall contact area, the second is inclined leg column top and in connection with the pillars of the beam damage is also very serious, In practical projects first should pay attention to strengthen the intensity of the pillars with beam joints and prevent damage; From the angle of energy we can see that shed tunnel is mainly through the concrete protective structure to absorb and consumption impact energy, soil cushion absorption and consumption impact energy is very limited, to alleviate the impact of concrete protective layer rolling damage, and suggestions in shed tunnel bearing place additional energy shock absorber to increases protection structure system soft degrees under the condition of minimize the shed tunnel weight, achieve the purpose of decrease shock energy.