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Kandelia obovata (S., L.) Druce and Sonneratia caseolaris (L.) Engl. are two dominant mangrove species in the subtropical coastlines of the Pearl River Estuary, China. The main aim of this study was to investigate the specific causes of K. obovata mortality versus S. caseolaris vitality on the west coast of Bao’an, Shenzhen, China and to propose sustainable management strategies for mangrove protection and future ecological planting restoration. Results showed that although both mangroves possessed simple and unstable community structures, S. caseolaris had a more tenacious vitality than the native species K. obovata, indicating that the former possesses stronger adaptability under adversity conditions. Moreover, the salinity of the seawater collection point 5 from the K. obovata plot was found to be lower than that of seawater collection point 1–3 from the S. caseolaris sample plots, indicating that no hydrologic connectivity existed in the K. obovata plots. In addition, the location of the drain outlet (seawater collection point 8) might be another potential risk factor for the dead of near K. obovata forests, implying that they were badly affected by poor oxygen and serious inorganic pollution, such as ammonium nitrogen, total phosphorus, and other inorganic substances. Depending on local circumstances, we should consider strengthening infrastructure construction to activate hydrological connectivity, reinforcing the stability of man-made mangrove communities, and controlling the pollution sources for sustainable mangrove protection and management on the western coast of Bao’an, Shenzhen, China.

Reforestation has been commonly adopted to increase the mangrove areas lost due to developments. A diverse phytoplankton community is critical to mangrove ecosystem functions; however, its compositions in planted mangrove habitats have seldom been reported. The present study, based on the temporal and spatial variations of phytoplankton community and water parameters, evaluated their relationships in a 20-year old artificially planted fringing mangrove in South China. Thirty-one phytoplankton taxa were identified from tidal water collected from three sites along a planted mangrove shoreline: within, and at the edge of mangroves, and at bare shoreline without mangroves. In all three sites, Bacillariophyta (diatom) was the most abundant phylum, dominated by Navicula and Nitzschia at 9.82-83.76% and 2.57-33.97%, respectively. The overall diversity ranged between 0.41 and 1.94. The temporal variations of phytoplankton and water parameters were more obvious than site differences. Higher phytoplankton diversity was found in summer, with increased green algae and cyanobacteria abundance accompanied by riverine discharge. There was site-specific dominance in some phyla between June and January, noticeably Chlorophyta, Cyanophyta, Dinophyta, and Euglenophyta. A potential toxic dinoflagellate Peridinium sp. was identified during fall and winter, serving as a warning to probable harmful bloom events. Multivariate statistical analyses revealed the abundance of major phytoplankton taxa significantly related to water physiochemical parameters, especially nitrate, ammonium, total phosphorous and orthophosphate. The present study suggests that mangrove vegetation may influence water quality and shape phytoplankton composition, but temporal differences were more significant. Compared with the protected natural mangroves in the National Nature Reserve nearby, this planted fringing mangrove habitat not only had lower nutrients, especially total nitrogen in tidal water, but also had different dominant phytoplankton species and lower species richness. The 20-year old artificially planted mangroves may still not serve the same ecological function as the protected natural mangrove forest.

Race and sex differences in the mathematical proportions of maxillary anterior teeth have been evaluated. However, studies exploring the relationship between the mathematical proportion of maxillary anterior teeth and maxillary dental arch form are lacking.The purpose of this clinical study was to determine if a correlation exists between the mathematical proportions of maxillary anterior teeth and 3 dental arch forms.Three hundred young participants were recruited according to predefined criteria, and images and maxillary casts were obtained. The perceived width and length of the maxillary anterior teeth were measured on the images by using a software program, and mathematical proportions, including width ratios and width-to-length ratios, were calculated for each. The casts were used to categorize each specimen into tapered, ovoid, or square groups by using a specific classification method, and the width ratios and width-to-height ratios of the 3 dental arch forms were compared. Statistical analysis was performed by using analysis of variance (ANOVA) or the Kruskal-Wallis H test to compare the mathematical proportions of maxillary anterior teeth among the 3 dental arch forms (α=.05). The intraclass correlation coefficient (ICC) was used to test the reliability of the investigators.Except for the width-to-length ratios of the central incisor, mathematical proportions were affected by the dental arch form. The perceived width ratios of the maxillary lateral incisor-to-central incisor gradually increased from the tapered arch to the ovoid arch and from the ovoid arch to the square arch, with mean ±standard deviation values of 0.71 ±0.04, 0.73 ±0.05, and 0.79 ±0.06, respectively. For the maxillary perceived width ratios of canine-to-lateral incisor, the ovoid arch had the maximum perceived width ratios (0.86 ±0.10), followed by the tapered (0.82 ±0.10) and square arches (0.77 ±0.11). The width-to-length ratios of the central incisor were not affected by the arch form (P=.075), and the width-to-length ratios of the lateral incisor increased as the arch form became flat, with respective values of 0.70 ±0.10, 0.74 ±0.10, and 0.76 ±0.10. For the width-to-length ratios of the canine, the ovoid arch had the maximum perceived width ratios (0.58 ±0.10), followed by the tapered (0.53 ±0.10) and square arches (0.52 ±0.10).The mathematical proportions varied among the 3 dental arch forms, and the dental arch form should be considered during the prosthodontic design of maxillary anterior teeth.

Salt stress is one of the major factors affecting plant growth and yield in soybean under saline soil condition. Despite many studies on salinity tolerance of soybean during the past few decades, the detailed signaling pathways and the signaling molecules for salinity tolerance regulation have not been clarified. In this study, a proteomic technology based on two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) were used to identify proteins responsible for salinity tolerance in soybean plant. Real-time quantitative PCR (qRT-PCR) and Western blotting (WB) were used to verify the results of 2-DE/MS. Based on the results of 2-DE and MS, we selected glucosyltransferase (GsGT4), 4-coumarate, coenzyme A ligase (Gs4CL1), mitogen-activated protein kinase 4 (GsMAPK4), dehydration responsive element binding protein (GsDREB1), and soybean cold-regulated gene (GsSRC1) in the salinity tolerant soybean variety, and GsMAPK4 for subsequent research. We transformed soybean plants with mitogen-activated-protein kinase 4 (GsMAPK4) and screened the resulting transgenics soybean plants using PCR and WB, which confirmed the expression of GsMAPK4 in transgenic soybean. GsMAPK4-overexpressed transgenic plants showed significantly increased tolerance to salt stress, suggesting that GsMAPK4 played a pivotal role in salinity tolerance. Our research will provide new insights for better understanding the salinity tolerance regulation at molecular level.

With the premise of investigating mechanical properties, the thermal conductivity of autoclaved aerated concrete (AAC) is a key index of self-insulation block walls for building energy conservation. This study focused on the effect of pore structures on the mechanical performance and thermal conductivity of AAC with the comparison of AAC base materials. Different kinds of AAC and their base materials were prepared and experimentally investigated. While maintaining a consistent mix proportion of the AAC base material, the pore structure of AAC was changed by the dosage of aluminum power/paste, foam stabilizer, and varying the stirring time of aluminum paste. The steam curing systems of AAC and the base material were determined based on SEM (Scanning Electronic Microscopy) and XRD (X-Ray Diffraction) tests. With almost the same apparent density, the pore size decreased with the increasing content of foam stabilizer, and the mixing time of aluminum paste and foam stabilizer has a great influence on pore size. The thermal conductivity test and compressive test results indicated that that pore size had an effect on the thermal conductivity, but it had little effect on the compressive strength, and the thermal conductivity of sand aeration AAC was 8.3% higher than that of fly ash aeration AAC, the compressive strength was 10.4% higher, too. With almost the same apparent density, the regression mathematical model indicates that the thermal conductivity of AAC increased gradually with the increase of pore size, but it had little effect on the compressive strength. From the test results of basic mechanical properties, the mechanical model of cubic compressive strength, elastic modulus, axial compressive strength, and splitting tensile strength was obtained. The proposed stress&ndash, strain relationship model could well describe the relationship of AAC and the base material at the rising section of the curve.

Autoclaved aerated concrete (AAC) self-insulation block masonry is often used for the infill walls in steel and concrete frame structures. To work together with the frame under earthquake action, it is essential to understand the seismic behavior of AAC self-insulation block masonry walls. In this paper, six AAC self-insulation block masonry walls were experimentally studied under the pseudo static test. The load-displacement hysteretic curves were drawn with the test data. The failure characteristics, loading capacity, stiffness degeneration, energy dissipation capacity and hysteretic behavior are analyzed. The results indicate that the blocks underwent internal failure due to the lower strength with a larger size, but the walls had good energy dissipation capacity with a rational bearing capacity. Accompanied by the influence of vertical compressive stress on the top surface of the walls, the cracking resistance, ultimate bearing capacity, deformability and energy dissipation capacity of the walls were affected by the masonry mortar joints. Comparatively, the walls with thin-layer mortar joints had better seismic performance than those with insulation mortar joints or with vertical joints filled by mineral wool plates. Finally, the shear capacity of the walls under seismic load is evaluated referring to the formulas of current design codes for masonry walls.

The pore structure has great influence on the mechanical properties and thermal conductivity of autoclaved aerated concrete(AAC). In this study, through the binary processing of the surface image of AAC, the pore diameter and number of AAC were obtained. Based on Monte Carlo method, the spherical coordinates of the air pores of AAC were generated by MATLAB software, and then they were imported into ANSYS software for modeling and grid generation. By comparing the pore size distribution and thermal conductivity between the finite element model and AAC product, to some extent, the finite element model in this paper is feasible. By the finite element analysis, the thermal conductivity is inversely proportional to the porosity and directly proportional to the pore diameter. Based on the thermal conductivity prediction model of porous materials, the mathematical models of porosity and thermal conductivity, pore diameter and thermal conductivity of AAC were established.

To promote the engineering application of recycled aggregate for concrete production with good adaptability and economic efficiency, this paper performed a campaign to investigate the flexural performance of steel fiber reinforced composite-recycled aggregate concrete (SFR-CRAC) beams matched with 500 MPa longitudinal rebars. The composite-recycled aggregate has features of the full use recycled fine aggregate and small particle recycled coarse aggregate, and the continuous grading of coarse aggregate ensured by admixing the large particle natural aggregate about 35% to 45% in mass of total coarse aggregate. The properties of SFR-CRAC have been comprehensively improved by using steel fibers. With a varying volume fraction of steel fiber from 0% to 2.0%, 10 beam specimens were produced. The flexural behaviors of the beams during the complete loading procedure were experimentally studied under a four-point bending test. Of which the concrete strain at mid-span section, the appearance of cracks, the crack distribution and crack width, the mid-span deflection, the tensile strain of longitudinal rebars, and the failure patterns of the beams were measured in detail. Results indicated that the assumption of plane cross-section held true approximately, the 500 MPa longitudinal rebars worked at a high stress level within the limit width of cracks on reinforced SFR-CRAC beams at the normal serviceability, and the typical failure occurred with the yield of 500 MPa longitudinal rebars followed by the crushed SFR-CRAC in compression. The cracking resistance, the flexural capacity, and the flexural ductility of the beams increased with the volume fraction of steel fiber, while the crack width and mid-span deflection obviously decreased. Finally, by linking to those for conventional reinforced concrete beams, formulas are suggested for predicting the cracking moment, crack width, and flexural stiffness at normal serviceability, and the ultimate moment at bearing capacity of reinforced SFR-CRAC beams.

With the premise of ensuring workability on a fresh mixture, the volume stability of hardened self-compacting steel fiber reinforced concrete (SFRC) becomes an issue due to the content of cementitious materials increased with the volume fraction of steel fiber. By using the expansive agent to reduce the shrinkage deformation of self-compacting SFRC, the strength reduction of hardened self-compacting SFRC is another issue. To solve these issues, this paper performed an experimental investigation on the workability, shrinkage, and mechanical properties of self-compacting SFRC compared to the self-compacting concrete (SCC) with or without an expansive agent. The calcium-sulfoaluminate expansive agent with content optimized to be 10% mass of binders and the steel fiber with a varying volume fraction from 0.4% to 1.2% were selected as the main parameters. The mix proportion of self-compacting SFRC with expansive agent was designed by the direct absolute volume method, of which the steel fibers are considered to be the distributed coarse aggregates. Results showed that rational high filling and passing ability of fresh self-compacting SFRC was ensured by increasing the binder to coarse-aggregate ratio and the sand ratio in the mix proportions, the autogenous and drying shrinkages of hardened self-compacting SFRC reduced by 22.2% to 3.2% and by 18.5% to 7.3% compared to those of the SCC without expansive agent at a curing age of 180 d, although the expansion effect of expansive agent decreased with the increasing volume fraction of steel fiber, the mechanical properties, including the compressive strength, the splitting tensile strength, and the modulus of elasticity increased with the incorporation of an expansive agent and steel fibers, which met the design requirements.

In this paper, experimental studies on compressive strength development of concrete with manufactured sand were carried out. Influences of stone powder content on long-term compressive strength of concrete with different water-to-cement ratios were analyzed. Tests results showed that when content of stone powder was less than 13%, it basically had positive correlation with the long-term compressive strength of MSC. Based on tests data, forecast model of long-term compressive strength of MSC considering curing age, water-to-cement ratio and cement’s compressive strength and density are proposed.

Graph partitioning is widely used in many diverse domains. Incremental graph is a member of Graph which evolves with time. Traditional static graph partitioning methods can not meet the requirement with the incremental graph partitioning due to expensive computational cost and long off-line processing time. In this paper, we propose a distributed incremental graph partitioning algorithm to partition the incremental Graphs into smaller components with Hadoop. Our method considers four different modification events of incremental graph partitioning. Moreover, we evaluate our method in Metis and the experimental results show our method is more effective in terms of different measurements than baselines.

Tapetal programmed cell death (PCD) is a prerequisite for pollen grain development in angiosperms, and cysteine proteases are the most ubiquitous hydrolases involved in plant PCD. We identified a papain-like cysteine protease, CEP1, which is involved in tapetal PCD and pollen development in Arabidopsis thaliana. CEP1 is expressed specifically in the tapetum from stages 5 to 11 of anther development. The CEP1 protein first appears as a proenzyme in precursor protease vesicles and is then transported to the vacuole and transformed into the mature enzyme before rupture of the vacuole. cep1 mutants exhibited aborted tapetal PCD and decreased pollen fertility with abnormal pollen exine. A transcriptomic analysis revealed that 872 genes showed significantly altered expression in the cep1 mutants, and most of them are important for tapetal cell wall organization, tapetal secretory structure formation, and pollen development. CEP1 overexpression caused premature tapetal PCD and pollen infertility. ELISA and quantitative RT-PCR analyses confirmed that the CEP1 expression level showed a strong relationship to the degree of tapetal PCD and pollen fertility. Our results reveal that CEP1 is a crucial executor during tapetal PCD and that proper CEP1 expression is necessary for timely degeneration of tapetal cells and functional pollen formation.

To meet the requirement of machine-made sand application in concrete structures, it is necessary to understand the bond properties of steel bar with machine-made sand concrete (MSC). Therefore, the experimental studies were carried out on the bond of plain steel bar with MSC by the central pull-out test method. Three specimens were cast as one group, 6 groups were tested considering the changes of strength grade of MSC and ordinary concrete. The bond-slip curves were measured and analyzed. The results show that the bond slip begins at the tensile side and transfers gradually to the free end before the entire slip turns up along the interface of plain steel bar and surrounded concrete, the largest average bond stress, i. e. the bond strength of plain steel bar corresponds to the initial entire slip of plain steel bar. With the increasing strength grade of MSC and ordinary concrete, the difference of slip at tensile side and free end becomes greater. Comparing that only appears in ordinary concrete with higher strength, the larger slips turn up while the bond stress reaches the largest for the plain steel bar in MSC. Larger scatter of bond strength is between specimens in the same group. Some plain steel bars yields with the beginning of entire slip along the interface.

Tests were carried out to study the durability of fine aggregate concrete and composite concrete simultaneously provided by the wet-sieving technique for the thermal insulation composite wall as building envelops. The workability of every concrete satisfied the basic requirement of cast quality. The composition analyses of concrete showed that compared with the ordinary concrete, the volume percent of coarse aggregate was increased and the volume percent of cement mortar was decreased due to that the residual coarse aggregate stayed on the sieve was blended with ordinary concrete, which increased the resistances of composite concrete to chloride penetration, water penetration and carbonization. Meanwhile, the resistances of fine aggregate concrete to chloride penetration, water penetration and carbonization were reduced due to the obvious increase of the volume percent of cement mortar.

A large impaired reinforced concrete beam with cracks was strengthened under self-weight action by the externally bonded steel frame composed with bottom steel plate and side hoop steel belts. The normal service loading behaviors of this beam were tested to verify the effectiveness of this strengthening method specified in current Chinese design code. Based on the analyses of test results, it can be concluded that: the deformation of flexural cross section of this beam fitted the assumption of plain cross section, the steel plate could effectively enhance the flexural stiffness and decrease the deflection of this beam, no new cracks appeared under the normal service loads, the cracks at bottom of this beam were more confined by the steel frame than those at web zone. Therefore, other measure should be taken to avoid the opening of web cracks.

Combined with the typical prestressed concrete continuous-beam bridge with 17m+28m+17m span over the main channel of the Central Line of South-to-north Water Transfer Project, two finite element models of this bridge, one considering and another without considering the pile-soil action, were built by the specialist bridge analysis software MIDAS/Civil 2011. The main vibration mode and its frequency were calculated by the self-vibration analysis, and the seismic response of the bridge was given out by the SRSS method of response spectrum method. Based on the calculations, the effect of pile-soil action on the dynamic characteristics and seismic behaviors of the bridge was studied. The results show that the pile-soil action brought the bridge structure into flexible, which led to the smaller vibration frequency but had no influence on the top two vibration modes. It also led to the larger displacement at top of piers and midspan of continuous-beam and the smaller internal forces of brake pear under the seismic action.

The paper introduces the experiments of sulfate attack on concrete under stress state. The concrete (MSFAC) was made with machine-made sand and fly ash. Before immersed in sodium solution with sulfate-ion concentration of 50000mg/L, the concrete beams with 100mm×100mm ×400mm dimension were in flexural tensile stress at levels of 20%, 40% and 60% of flexural tensile strength by the special designed stress devices. The sulfate-ion content in different erosion depths of concrete was measured at attack age of 30, 90, 180, 270, 360, 540 and 720 days by the chemical titration method. The results show that the apparent damage such as rough surface and cement past peeling off became more serious with the increasing tensile stress level and the prolongation of attack age, while much more obvious crystallization of gypsum was in surface cracks, the sulfate-ion content in the first layer near surface did not reflect the real status of concrete affected by tensile stress levels. The sulfate-ion contents of inside layers increased basically with the attack age at stress levels lower than 60% of tensile strength of concrete. In conditions of the experiment, the sulfate-ion content reduced when the attack age was longer than 540 days at the stress level of 60%.

The wavelet and EMD method are taken in order to accurately extract the fault information from the audio signal with a lot of noise. The bearings were studied for the object. This paper proposed a method based on wavelet and EMD frequency characteristics of the acoustic signal information extraction, and the method used in bearing fault feature extraction. The experimental results show that: the method can effectively extract the fault characteristic frequency of bearing.

Three-dimensional digital model of hot rolling-mill housing was built. The natural frequency and vibration mode shape of the first 10 order modes of hot rolling mill housing were calculated using ANSYS software. The vibration mode shape was studied in detail. The striking vibration signal and subsequently the natural frequencies were measured by placing two 3-Dimensional accelerators in the key points of the rolling mill horsing. Theoretical calculations and experimental results verified each other，high agreement was shown between the experimental results and the theoretical results. The first 10 mode frequency all appeared in the experiment signal with low error. The main mode frequency (117.3Hz) of the experimental signal has the lowest error down to 0.07%.

Tests were carried out to study the concrete attacked by magnesium sulfate solution. The concrete specimens were exposed in the magnesium sulfate solution with three different concentrations for 360 days. At the exposure times of 90 days, 180 days, 270 days and 360 days, the properties of concrete such as the mass change, the compressive strength and the tensile strength were measured, and the contents of sulfate-ion diffusing into different depths of concrete were determined. Their changes with the solution concentration and the exposure time are analyzed in this paper, which could be used as reference for the protecting of concrete against the attack of magnesium sulfate.

Combined with the design of a bridge with prestressed concrete continuous box-girder, and in accordance with the Chinese guidelines of seismic design for highway bridge, the numerical models with and without considering the pile-soil action were built using Midas Civil software. The response spectrum method was used to analyze the seismic response of the bridge under E1 and E2 seismic actions. The vibration characteristics such as frequency, period and mode as well as the internal forces and displacements of piers are discussed in view of the effect of the pile-soil action.

Cuscuta campestris , a dodder, can parasitize and suppress a scrambling herbaceous to semi-woody perennial vine, Mikania micrantha , one of the most destructive weeds in the world. To assess the effects of the mixed residue of C. campestris and M. micrantha on the subsequent plant community, we conducted a one-year experiment on the germination and seedling growth of subsequent plant community after the application of C. campestris. Seven treatments of varying proportions of C. campestris and M. micrantha residue on 21 subject trees and shrubs, which were commonly found in South China, resulted in a germination rate of 35.3% for all 8 715 seeds from 18 species, ranging from 5.7 to 81.9%; the remaining 3 species failed to germinate. ANOVA analysis showed that the residue did not affect the germination, growth, or mortality of the trees and shrubs. The germinated C. campestris seeds from the residue coiled the seedlings of most of the species, but less than 4% host death caused by C. campestris. In addition, the residue did not affect the germination of the herbaceous seedlings originating from the loam, and the similarity coefficients of the germinated seedlings between the treatments were very high. These results suggested that the residue had no negative impact on the germination and early seedling stages of the tree, shrub and grass species of the subsequent plant community. The use of C. campestris residue had a positive effect on the growth of M. micrantha , but it did not change the trend of M. micrantha being suppressed because re-parasitization occurred soon after the growth restarted. No negative effect was detected on the other species as a result of the parasitization of C. campestris or by the use of the mixed residue. This suggests that C. campestris is likely to be an effective and promising ecologically safe native herbaceous agent for controlling M. micrantha.

This paper introduces the design of a small-size single-pylon cable-stayed bridge to be built in Xingtai city, China. The main structural members of this bridge including box-girder, stayed cables and pylon were selected to meet the requirement of bearing properties and artistic display. The numerical model for analyzing the static properties of the bridge structure was made by the design software MIDAS/Civil. The distribution and ultimate value of internal forces, stress and displacement of these main members are summarized, which provide the basis for calculating the reinforcement and prestressed strands of the bridge.

A lumped mass model with two degrees of freedom for the vertical vibration system of four roller hot strip rolling mill stand is proposed, and then the parameters of dynamic model , include the equivalent mass , equivalent stiffness and its natural frequencies, were calculated by MATLAB package. The correctness of the model is verified via field vibration testing and signal analysis in the strip rolling process. Comparative the six degrees freedom model, the two degrees freedom model of our proposed is simplified reasonability and the model accuracy is maintained certainly . The two degrees freedom model is critical for the research of digital simulation of the strip rolling process. The research result have important theoretical and practical significance for the parameter optimization of the AGC system , vertical vibration control, the product quality improvement and the rolling speed increase for the rolling mill system.

Combined with the practical design of a prestressed concrete continuous box-girder bridge with changed sections, the effect of side-web slope on the loading properties of this bridge was analyzed. The numerical modes of this bridge were built using the specialist FEM software, 5 side-web slopes were considered by changing the width of box floor. The results show that the changes of side-web slope influence the mid-span deflection of box-girder in a small range under vehicle load, but affect obviously on the transversal loading properties such as crack width and flexural resistance of the box roof. Based on this, the suitable side-web slope is selected. It may be referenced by the similar design of this kind of bridges.

Fly ash (FA) is always used as the pulverized admixture of concrete with machine-made sand to improve the bad workability of fresh concrete such as lower flowing and serious bleeding. According to the specification of Chinese standard, there are three ways of admixing FA into concrete including the additional admixing, the equal-mass replacing cement and the over-mass replacing cement. This paper researches the possibility for unifying these three ways in the mix proportion design of concrete with machine-made sand by fitting the test data with the formula of water to cement ratio. The regression coefficients are given out corresponding to these three ways, the influences of FA on concrete are discussed. The issues in current mix proportion design methods are pointed out. To efficiently play the function of FA as the beneficial admixture of concrete, the activity of FA should be considered as a key factor in the mix proportion design of concrete.

Due to many different characteristics such as irregular polygon particle with pointed edges, rough surface and larger content of stone powder, machine-made sand has ignorable effects on the properties of concrete. As the basis for the design of concrete structures, the relations among the basic mechanical properties of concrete such as compressive strength, tensile strength, flexural strength and elastic modulus should be clearly understood. This paper summarizes the test data from the published references, and discusses the relations among these properties by statistical analyses compared with those of ordinary concrete. The results show that the axial compressive strength and the tensile strength can be prospected by the same formulas of ordinary concrete specified in current Chinese design code, but the prospected tensile strength should multiply a reducing coefficient when the strength grade of concrete is lower than C30. The elastic modulus of concrete with machine-made sand is larger than that of ordinary concrete, which should be prospect by the formula in this paper. Meanwhile, the formula of flexural strength is suggested.

Experiments were conducted to study the mechanical properties and water permeability of recycled aggregate porous concrete. The orthogonal test was designed considering four parameters including water to cement ratio, cement content, grain series of recycled aggregate and aggregate to cement ratio, each parameter was set at three levels. Performances of porous concrete were measured such as cubic compressive strength, flexural strength, continuous porosity and water penetration coefficient. Test results are analyzed on the basis of orthogonal test method, the optimum proportions corresponding to every test parameters are given out. The ranges of every test parameters are also proposed. It provides a reference for constructing porous concrete roads by recycled aggregate made of old concrete from dismantled buildings.

A lumped mass model with six degrees of freedom for the vertical vibration of four roller hot strip rolling mill stand was proposed, while its natural frequencies were calculated by MATLAB software. The numerical calculation results were proved more accurate through field vibration test. This vertical vibration model can be applied for dynamic simulation and structural dynamic modification with important theoretical and practical significance in mastering the vibration characteristics of four-roll mill, avoiding vertical self-excited vibration and improving production efficiency.

Experiments were conducted to study fly ash concrete (FAC) attacked by sulphuric acid. The cubes with dimensions of 100 mm were cast and immersed in sulphuric acid solution with different pH values of 2, 3 and 4, and tested at exposure times of 28 d, 56 d, 90 d, 150 d and 365 d respectively. The compressive strengths of concrete were tested, and the SO42- contents of concrete at different depths were measured with powder samples by the chemical titration method. The results show that FAC has certain ability to resist corrosion of sulphuric acid though exposed surfaces were damaged at long-term exposure times, the concrete strength at same exposure time decreases with the increasing density of sulphuric acid solution, the SO42- mainly contains in shallow layer of concrete while the content decreases obviously with the increasing depth of concrete. With the increasing density of sulphuric acid solution, phenomena of surface cement paste peeling off surface of concrete and crystal CaSO4 separated out of concrete became seriously. The deterioration mechanisms of FAC attacked by sulphuric acid are discussed.

Experiments were carried out to investigate the dry-shrinkage of masonry mortar affected by mass content of polypropylene fiber. The results show that proper content of polypropylene fiber is helpful to effectively reduce dry-shrinkage of mortar especially in early age, the reduction relates to water to cement ratio of mortar. Meanwhile, the relationships of water to cement ratio and content of polypropylene fiber in affecting dry-shrinkage of masonry mortar are analyzed, which can be as reference for selecting such optimum values as water to cement ratio and content of polypropylene fiber in practices.

Experiments were carried out to investigate such basic properties as workability and strength of masonry cement mortar affected by mass content of polypropylene fiber. The results show that proper mass content of polypropylene fiber is helpful for effectively adjusting consistency and layering to bring better workability of fresh mortar, the relative higher bending strength of mortar can be got by admixing reasonable mass content of polypropylene fiber while slight improved compressive strength reaches. The relationships of water to cement ratio and mass content of polypropylene fiber in affecting these basic properties of masonry mortar are analyzed, which can be as reference for selecting optimum water to binder ratio and mass content of polypropylene fiber in practices.

Experiments were carried out to study such basic properties as workability and strength of masonry cement mortar affected by mass content of cement equally replaced by stone powder. The mortar was designed in strength grade of M20 with three kinds of mix proportions, three replacing ratios of cement by stone powder. The results show that part of cement equally replaced by stone powder irregularly influences consistency and layering of fresh mortar but still brings fresh mortar into better workability; the optimum mass content of cement equally replaced by stone powder relates to the water to binder ratio of mortar, which are 5 %, 10 % and 15 % successively corresponding with 1.0, 0.9 and 0.8 water to binder ratio. Comprehensively concerned about the ratio of bending to compressive strengths of mortar, the referenced mix proportions of mortar with stone powder are proposed for application in practices.

The behaviors of linkage of built-in insulation reinforced concrete composite wall subjected to gravity load were experimental studied in this paper. The gravity load was computed as the sum of self-weights of thermal insulation layer, external concrete cover and surface decoration materials. Steel tube with square section was designed as the linkage. Two specimens modeling practical RCCW were cast and tested in Lab, many rectangular steel plates were used to simulated the uniformly distributed load on surface of external concrete cover. The relative displacement between inside structural reinforced concrete wall and external concrete cover, the strains of surface concrete and steel tube walls were measured. Tests were finished when load was over 3.24 times of design value, no relative displacement and only smaller concrete strains were observed, maximum tensile and compressive stresses of steel tube walls were only 6.3 % of design strength. It is concluded that the linkages are safe and the entirety of RCCW is good enough to satisfy the design requirements.

Based on a series tests, the properties of proto-machine-made sand of gravel such as grain feature, fineness modulus, grading, density, void ratio and MB value as well as the fineness distribution of stone powder were studied, the influences of content of stone powder on these properties of sand and strength of cement mortar were investigated. The results are introduced in the paper, some of them contribute to explain the special properties of concrete mixed with proto- machine-made sand.

Experiments were conducted to study the workability of fresh concrete and basic mechanical properties of hardened concrete with gravel-crushed proto-machine-made sand. Effects of water to cement ratio and content of stone powder were mainly considered. Based on the test and before, the values of practical parameters in formula are obtained for calculating mixed strength of concrete, and the beneficial range of water to cement ratio is proposed. Meanwhile, the reasonable water content, sand ratio and content of stone powder are also suggested.

The behaviors of linkage of built-in insulation reinforced concrete composite wall subjected to wind load were experimental studied in this paper. Three specimens modeling practical RCCW were cast and tested under static and repeated loads. The relative displacement between inside structural reinforced concrete wall and external concrete cover, the strains of steel tube walls were measured. The results show that specimens damaged with cracks at interface between external concrete cover and thermal insulation layer when load was up to 11.3 times of design value, the maximum stress of steel tube walls reached 25.3 % design strength, the safety factor is 1.67 when concrete cracked at steel tube. Therefore, the linkages are reliable to bear wind load on external concrete cover.

A novel covert communication method of digital image is presented, based on generalized fuzzy c-means clustering (GFCM), human visual system (HVS) and discrete cosine transform (DCT). Therefore, the original image blocks are classified into two classes according to specified characteristic parameters. So one block is suited for embedding security information, but the other block is not. Hence the appropriate blocks can be selected in an image to embed the security information by selectively modifying the middle-frequency part of the original image in conjunction with HVS and DCT. Furthermore the maximal information strength is fixed based to the frequency masking. Also to improve performances of the proposed algorithm, the security information is modulated into the chaotic modulation array. The simulation results show that we can remarkably extract the hiding security information and can achieve good robustness with common signal distortion or geometric distortion and the quality of the embedded image is guaranteed.

The mechanical properties of concrete mixed with composite coarse-aggregate were studied by the orthogonal test method, in which the four factors such as the cement content, the percent of cement replaced by fly ash, the percent of crushed limestone with grain size of 16-25 mm replaced by lightweight aggregate with the same grain size and the water to binder (cement + fly ash) ratio were considered. The results show that the water to binder ratio is the most effective factor influencing all of the mechanical properties, the mechanical properties except the splitting tensile strength are less influenced by the cement content, the elastic modulus and axial compressive strength as well as flexural tensile strength is largely affected by the replacement of cement by fly ash. The effect of the replacement of crushed limestone by lightweight aggregate is much more obvious on the cubic compressive strength than on the axial compressive strength, and larger on the flexural tensile strength than the splitting tensile strength.

To improve the application of the new proto-machine-made sand in structural engineering, tests are carried out to study the drying shrinkage of concrete affected by stone powder in proto- machine-made sand. The target cubic compressive strength of concrete is 55 MPa, the main factor varied in mix proportion of concrete is the contents of stone powder by mass of proto-machine-made sand from 3 % to 16 %. The drying shrinkage strains of concrete are measured by the standard method at the ages of 1 d, 3 d, 7 d, 14 d, 28 d, 60 d, 90 d, 120 d, 150 d and 180 d. Based on test results, the drying shrinkage of concrete affected by the contents of stone powder in proto-machine-made sand is analyzed and compared with that of similar test of concrete with traditional machine-made sand, which shows that there is the optimum content of stone powder resulting in the lower drying shrinkage of concrete. The formula for predicting drying shrinkage strain of concrete is proposed.

The new reinforced concrete composite wall (RCCW) with inner insulating layer of polystyrene panel was developed to improve the durability of external thermal insulation plate on walls. The composite structure and construction method of the RCCW is briefly introduced in this paper. The thermal insulation behaviors such as conduct heat coefficient and total heat resistance of RCCW are tested by the protection chest method, the measured and calculated results of thermal insulation properties of the RCCW are compared with each other, the effect of heat-bridge resulted from connected concrete supports of specimen and bottom side concrete of specimen covering inner insulating layer on the test results is discussed.