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The aim of this study is to investigate the effect of SiC particle pretreatment, aluminum matrix particle size and sintering temperature on relative density, hardness, microstructure and wear resistance to SiC particle einforced aluminum matrix composites. To this end, the amount of 16.7 wt.% SiC with average particle sizes 20μm was used along with pure aluminum of average particle size of 75 μm and 25μm. Powder metallurgy is a method used in the fabrication of this composite in which the powders were mixed using a planetary ball mill. By analyzing SEM micrograph and the Property test, it is concluded that SiC particle pretreatment has significant effect on the morphology of pecimens. pretreatment increase the interface adhesion, improve the wettability. SiC is uniformly distributed in the matrix, with good relation to the substrate, the maximum hardness is 51.1HB, the minimum wear rate is 0.1684%, while the density is 97.3%.For the same SiC content and particle size, the smaller the particle size of aluminum matrix is, the higher wear resistance of composite materials is on condition that others are same, the higher sintering temperature and the higher the wearability of composites, the wear resistance of the composite material is significantly improved after SiC pre-processing.The relative density increases with increasing aluminum matrix particle sizes under the same pressure and the holding time. The actual density of all samples reached the theoretical density over 96%, to a maximum of 98.9%.

Affordable housing is an important part of China's housing security system. This policy is adapted to the actual situation of our country. The core advantage of the affordable housing is prices. It is to ensure the healthy development of affordable housing and a premise for the real role. How to make affordable housing for protection of the population can not only afford but also comfortable stay, developed pricing is the most important issue of its construction, it relates to the different interests of the class, a scientific and reasonable to take into account the different interests sectors of the pricing model. It helps to achieve social stability, improve the construction, regulatory and pricing mechanisms of affordable housing, and has a theoretical and practical significance.

The current two-dimensional (2-D) parameters for surface assessment (Ra and Pc) could not actually reflect functional properties of bearing and lubricant retention capabilities of steel sheets and rolls surface. Based on ARM9 development board, this paper has been working on secondary development of M1 mobile surface roughness meter, creating a model of calculating three-dimensional (3-D) functional characteristic parameters with 2-D profiles, and optimizing influence factors with Genetic Algorithms (GA). By comparing with measurement results by white-light interfering profile meter, the measurement error of the developed system is within10%, which was proved to be practical in the factory.

The objective of this study was to carry out a meta-analysis of the efficacy of gemcitabine+platinum agent regimens in the treatment of advanced biliary tract cancer (BTC). PubMed and Google Scholar were searched using the following combination of search terms: gemcitabine, oxaliplatin, cholangiocarcinoma, biliary, gallbladder, bile duct. Studies were eligible for inclusion in the meta-analysis if they were randomized trials on the use of gemcitabine plus a platinum agent for the treatment of advanced (unresectable or metastatic cancer) BTC. Outcomes of interest were response rate, overall survival, and progression-free survival. Pooled odds ratios/differences in median survival and 95% confidence intervals (CIs) were determined for each outcome. A total of 47 records were identified in the initial search. Ultimately, three open-label randomized trials (two phase 2 and one phase 3) met the eligibility criteria and were included in the meta-analysis. Two studies compared gemcitabine plus cisplatin with gemcitabine alone, whereas the other study compared gemcitabine plus oxaliplatin with fluorouracil-folinic acid. The total number of patients in the studies ranged from 54 to 410. The overall analyses revealed that all survival outcomes assessed were significantly more favorable for patients treated with gemcitabine plus platinum agents than for patients not treated with this combination. Response rates: odds ratio=2.639, 95% CI=1.210-5.757, Z=2.439, P=0.015; pooled difference in median overall survival=3.822 months, 95% CI=1.798-5.845 months, Z=3.702, P

This paper presents the data fusion survivability analysis model of wireless sensor network (WSN) based on stochastic Petri net (SPN). First, the definition of data fusion survivability is put forward, and the data fusion model of WSN is constructed. Second, the SPN modeling method of security events, which influences the WSN, is described. Lastly, simulation experiment proves the correctness and effectiveness of the modeling of WSN data fusion survivability analysis based on SPN. This model can provide the theoretical basis and guide for designing a survivable WSN.

mi-rigid base on crack resistance, using orthogonal experimental design method, arranged 16 groups of orthogonal test and conducted the water content test and drying shrinkage test that aimed at various ages from 5d to 50d respectively. The results indicated that with the increasing of waste asphalt content, the shrinkage gradually increasing and the maximum reached when the dosage of waste asphalt concrete was 55%, since then, with the increasing of waste asphalt content, the shrinkage gradually decreasing and the range was largely. Fiber has little effect on moisture loss and shrinkage, with the increasing of fiber content, the moisture loss of materials with different ages increased gradually and the maximum loss rate reached when the dosage of fiber was 4, then the moisture loss decreased gradually after that. As for shrinkage, it reached minimum value when the dosage of fiber was 2.5. Mixing waste asphalt concrete and fiber in reasonable dosage can improve the crack resistance of materials.

The tempering temperature on microstructure and mechanical properties of 35CrMnSiMo cast steel are studies in this article. Results showed that 880°C×30min 35CrMnSiMo cast steel after quenching water, hardness up to 49.6HRC, reached 39.04 J/cm2 toughness. Tempering temperature selected 200°C, 400°C and 600°C, respectively with the increase of the tempering temperature plummeting hardness and impact toughness are on the rise, but at 400°Cdecreased. Photos can be seen from your organization after quenching, which contains a lot of lath martensite, a small amount of lump some residual austenite and martensite, 200°C tempering martensite has been reduced, some of carbide precipitation into tempered martensite. Tempering of martensite quenching slats or flake, it is made of flake martensite and small ξ carbide distribution.

Objectives The aim of this study was to compare 3D accuracy of tooth image reconstruction from three kinds of CT scans using 3D superimpositional method. Methods 18 sound extracted human teeth were scanned by 3D optical system, spiral CT, micro-CT, and cone-beam CT scanner. The digital teeth images reconstructed from three kinds of CT scans were superimposed onto the standard image from optical scans respectively. Distribution patterns of shape discrepancy were presented using histogram, as well as showed in different colors on the superimposed imagines. The ratio of voluminal discrepancy versus the volume of the standard image (RVD/VS) was calculated and analyzed, using the matched-pair t-test and rank sum test. Results Compared with the standard tooth image, the average RVD/VS of digital teeth images by the micro-CT, cone-beam CT, spiral CT scans were 5.11%, 20.73%, 24.60% respectively, and there were statistically significant difference among the three kinds of CT scans (P

This paper mainly studied the high temperature quenching oil quenching, tempering temperature on the influence of high strength steel mechanical properties of wear resistant. The results show that high strength and toughness wear-resistant cast steel with 880°C× 30min after oil quenching, the hardness of 38.6HRC steel, the impact toughness value reaches 40.18J/cm2. After 200°C, 400°C and 600°C tempering, with the increase of the tempering temperature, the hardness decreased linearly, as by 600°C tempering, the hardness has been reduced to 22.3HRC. Impact toughness with the tempering temperature, the overall upward trend, the impact toughness of some reduced at 400°C, the highest impact toughness value reaches 113.34J/cm2. From the fracture morphology can be seen, with the increase of tempering temperature, ductile fracture increased, by 600°C tempering is dimple fracture, obviously can not see the traces of brittle fracture.

A secure and stable equipment management system is very important to an enterprise, the use of advanced technology in equipment management system, now the popular application of advanced distributed database operation mode, make the equipment management information system has strong practicability and high reliability. The equipment management work requirements, procurement plan, use, repair, and scrap the whole process of information recording, tracking, monitoring, both capital plan, which is the organic combination of physical and financial, and provides users with detailed and accurate information and convenient management means.

This paper proposes a kind of on-line control system for operation mode in substations, which can read data on-line from EMS, and then calculate total loss of substations in parallel operation, split operation or individual operation mode. According to the result, the system can select the most optimized way and feed the conclusion back to EMS, which can make substations operate in the most optimized way. The system is suitable for optimization of substation in rural power grid.

Trajectory planning and simulation of docking tests on the ground for space simulator is one of key technologies to complete space docking mission. A new time-optimal trajectory planning algorithm is proposed based on minimum acceleration limitation. It is realized by searching maximum acceleration to obtain the best time according to PSO (particle swarm optimization). Through calling matlab script by LabView and capturing control set points, 3D CAD model is driven to verify the rationality of the trajectory planning algorithm and model design. The simulation results show that the simulator using the proposed algorithm can move smoothly and reliably meeting the experiment requirements.

A series of N-arylmorpholines 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n was obtained by cyclocondensation of arylamines and diethylene glycol dimesylate under microwave irradiation in an aqueous potassium carbonate medium. The reaction is rapid and convenient, and a variety of functional groups are tolerated in the process.

Pharmaceutical compounds were increasingly detected in environmental matrices but little is known whether these compounds would transport to coastal zones via watersheds. Three typical tidal rivers in southeastern China were selected and 15 surface sediment samples (0-10 cm) were collected along a 50-km tidal section of each river. Surface sediment samples were frozen-drying and then extracted for pharmaceutical compounds by an accelerated solvent extraction system. The pharmaceutical compounds in extracts were scanned using a high-performance liquid chromatography/tandern mass spectrometry (HPLC-MS/MS). Three hundred and thirty compounds from nine pharmaceutical groups were detected with signal-to-noise above three (detectable level) in the surface sediments, of which 186 compounds were with a signal-to-noise above ten (measurable level). Of all, 291 and 80 compounds were detectable and measurable in all the three rivers, respectively. The Jiulong River showed a high load of pharmaceutical compounds in surface sediment than other two rivers. Of the nine pharmaceutical groups, the antihistamines and detoxification group and anti-infective drug group contributed five dominant compounds in the surface sediments in all the three rivers. Natures of pharmaceutical compounds rather than the sediment properties (pH, EC, and total carbon content) might influence their residues. The incredible number and intensity of pharmaceutical residues were detected in tidal surface sediments of the three rivers indicating that the pharmaceutical contamination should be strongly considered in China. Source identification and eco-toxicity assessment should be taken into account in the future study. Therapeutic medicine managements need to be strictly improved at a watershed scale to reduce loads of pharmaceuticals into aquatic ecosystems.

Fine zirconium diboride (ZrB2) powders with high purity were successfully prepared by combustion synthesis through magnesiothermic reduction process in Mg–B2O3–ZrO2 system. The reaction mechanism was investigated by differential thermal analysis and quenching experiment. The results show that the whole magnesiothermic reduction process includes three stages: first, molten B2O3 and Mg formed above the temperature of 650 °C, and glassy B2O3 and solid ZrO2 particles were coated on the surface of the molten Mg; thus, the hollow balls can be formed when the molten Mg was exuded under capillary function. Second, ZrO2 particles reacted with molten Mg to form Zr and MgO with dissolution–precipitation mechanism, which released a large amount of heat to induce the diffusion reaction between B2O3 and Mg to form B and MgO. Last, Zr reacted with B to form ZrB2 grains. The preparation of ZrB2 by self-propagating synthesis in Mg–B2O3–ZrO2 system is a solid–liquid-liquid reaction.

In this article, the authors use of Si, Mn, Cr as the main alloying element, developed a tough wear resistant cast 35CrMnSiMo, after casting, to obtain a wear-resistant cast steel with a hardness and impact toughness mechanical performance testing, metallurgical microscope and scanning electron microscope analysis of the microstructure. The results show that, the cast 35CrMnSiMo 850 °C austenitizing insulation 30min and then quenched, the material water hardened degrees is much larger than the oil hardened degrees. The the water hardened than oil hardened degrees up 28.5%. Metallographic photo clearly see a lot of lath martensite, the small amount of lath martensite and retained austenite, the oil quenching microstructure edge outline is somewhat vague, while clear the water quenching microstructure edge contour darker, impact toughness with hardness is inversely proportional to the sample.

This paper mainly through the experimental study on the heat treatment process and mechanical properties of cast steel 35CrMnSiMo.According to the effect of alloy elements in design of a high-toughness abrasion-resistant cast steel, Cr, Mn, Si, as the main alloy elements, supplemented by a small amount of Mo, the casting molding, for hardness and impact toughness test of mechanical properties of experimental steel. The results show that, the as-cast 35CrMnSiMo by 880 °C, quenching for 20min then, the same quenching temperature, quenching hardness of materials is far greater than the oil quenching hardness. Water quenching hardness up to 25% higher than the oil quenching hardness, The impact toughness of specimen is inversely proportional to the contrast relationship Hardness.

Columnar crystaldendriteequiaxial dendritescolumnar crystalNanosized powder was synthesized by direct-reactive precipitation process using a stoichiometrical mixture of TiCl4, BaCl2 as the reactants while NaOH as precipitant. Under the ratio of Ba to Ti is 1.02, PH=13, three reaction temperature of 70°C, 80°C and 90°C were conducted respectively. Morphology and phase structure of powder were investigated, and the influence of reaction temperature on powder morphology was discussed. The result indicates that synthesized powder is single cubic BaTiO3 and contains no impurities. BaTiO3 powders generally show spherical, and average particle size decreases with increasing reaction temperature. When reaction temperature is 80°C, BaTiO3 powder has best uniformity and dispersivity with the diameter of 80-100nm. The influence of reaction temperature on powder particle size can be attributed to the corporate contribution of nucleation and growth rate. Polyglycol as surface active agent has a significant effect in restraining agglomeration.

Nitrogen-doped TiO2 nanotubes (N-TNTs) were fabricated on the titanium foil by anodic oxidation and followed by annealing at NH3 environment. Highly ordered nanotubes, roughly 150 nm in the diameter and 20 μm in the length, were synthesized on the titanium foil. By controlling oxidation voltage, the thick TiO2 nanotubes were peeled off from the titanium substrate. In one step annealing at NH3 environment, nitrogen replaced oxygen and doped into TiO2, but anatase phase was formed.

Simple joint is a common connection in tubular structures. Local buckling occurs in panel zone when the joints bear heavy loads, and local buckling will reduce the bearing capacity and stiffness. In order to improve the bearing capacity of tubular joints, the joints need to be strengthened. In this paper, the bending performance of the joints will be enhanced by welding a tile shaped plate outside the surface of panel zone of chord member. By ANSYS finite element program, the bearing capacity of the joint with different tile shaped plate was analyzed. The results showed that the bearing capacity of the joints experience obvious change with variation of thickness, whereas the bearing capacity has no change with variation of radian.

the control strategy has a direct impact on the performance of active power filter. Creating system model in the simulation software to research and analyze. Results show that the hysteresis comparison control method can track the harmonic current accurately, and control inverter circuit generate compensation current quickly and accurately. And doing spectrum analysis for the power grid currents before, the spectrum figures show that the power grid current harmonics has been suppressed greatly, and the compensation effect is very significant.

Hard PZT (PZT4)-based composites embedded by ZnO nanoneedles (denoted as PZT/ZnOn) were fabricated by a solid state sintering technique. The characteristic diffraction peaks of the perovskite PZT and ZnO phases were identified from the studied composites, indicating the retention of ZnOn. With increasing ZnOn content, the grain size of the composites was reduced gradually. In contrast with the pure PZT, the PZT/ZnOn composites possessed more excellent mechanical properties, while the piezoelectric properties were reduced by a certain extent. The best mechanical properties of PZT/ZnOn composites were obtained by sintering at 1,150 °C with 1.5 wt% ZnO nanoneedles addition: fracture toughness K IC ~ 2.04 MPa m1/2, flexural strength σ f ~ 105.44 MPa, compressive strength σ c ~ 543.89 MPa. The piezoelectric properties of the PZT/ZnOn composites were found to be lower than that of the pure PZT with dielectric permittivity e r of 768–893, piezoelectric coefficient d 33 of 240–260pC/N, mechanical quality factor Q m of 340–650 and planar electromechanical coupling k p of 0.5–0.55.

Simple joint is a common connection type in tubular structures. In this joint, one or more tubes are welded directly on the surface of another tube. Local buckling occurs in panel zone when the joint load is heavy, and such local buckling will reduce the bearing capacity and stiffness of the joint. In order to improve bearing capacity of tubular joints, the joint needs to be strengthened. In this paper, the bending performance of the joint will be enhanced by welding two annular plates inside the surface of panel zone of chord member. By ANSYS finite element program, the bearing capacity of the joint with different inner annular plate was analyzed, including design bearing capacity and ultimate bearing capacity. The results showed that comparing to annular plate thickness variation, the width variation and interval variation have much more influence on the bearing capacity of the joint.

To assess the role of time-intensity curves (TICs) of the normal peripheral zone (PZ) in the identification of biopsy-proven prostate nodules using contrast-enhanced transrectal ultrasound (CETRUS). This study included 132 patients with 134 prostate PZ nodules. Arrival time (AT), peak intensity (PI), mean transit time (MTT), area under the curve (AUC), time from peak to one half (TPH), wash in slope (WIS) and time to peak (TTP) were analyzed using multivariate linear logistic regression and receiver operating characteristic (ROC) curves to assess whether combining nodule TICs with normal PZ TICs improved the prediction of prostate cancer (PCa) aggressiveness. The PI, AUC (p p = 0.011 and 0.040 respectively) values of the malignant nodules were significantly higher than those of the benign nodules. Incorporating the PI and AUC values (both, p p = 0.076 and 0.159 respectively), significantly improved the AUC for prediction of malignancy (PI: 0.784–0.923; AUC: 0.758–0.891) and assessment of cancer aggressiveness (p

Parthenolide (PN), a sesquiterpene lactone isolated from the herbal medicine feverfew (Tanacetum parthenium), was reported to possess neuroprotective activity. However, the neuroprotective effect of PN against cerebral ischemia/reperfusion (I/R) injury remains unclear. Therefore, the aim of the present study was to explore the neuroprotective effects of PN against oxygen-glucose deprivation (OGD)-induced apoptosis in PC12 cells and the underlying mechanisms. Our results demonstrated that PN ameliorated OGD/R-evoked neuronal injury and oxidative stress in PC12 cells. In addition, PN notably decreased HIF-1α expression, as well as inhibited apoptosis in PC12 cells after OGD/R. Furthermore, PN pretreatment significantly enhanced the phosphorylation of Akt and GSK-3β in PC12 cells exposed to OGD/R. In conclusion, the present study demonstrated that PN exhibits a neuroprotective effect against OGD/R through activation of the Akt/GSK-3β signaling pathway. Our findings suggest that PN has the potential to serve as a novel therapeutic agent for cerebral I/R injury.

Biochar application to agricultural soil is an appealing approach to mitigate nitrous oxide (N2O) and methane (CH4) emissions. However, the underlying microbial mechanisms are unclear. In this study, a paddy soil slurry was incubated anaerobically for 14 d with biochar amendments produced from rice straw at 300, 500, or 700 °C (B300, B500, and B700) to study their influences on greenhouse gas emissions. Illumina sequencing was used to characterize shift of soil bacterial and archaeal community composition. After peaking at day 1, N2O emission then sharply decreased to low levels while CH4 started to emit at day 3 then continually increased with incubation. Compared to control soil (57.9 mg kg− 1 soil), B300, B500, and B700 amendments decreased N2O peak emission to 17.9, 1.28, and 0.59 mg kg− 1, mainly due to increased soil pH. In contrast, the amendments enhanced CH4 production from 58.2 to 93.4, 62.6, and 63.4 mg kg− 1 at day 14 due to increased soil dissolved organic carbon. Abundance of denitrifying bacteria (e.g., Bacilli, 7.07–13.6 vs. 16.9%) was reduced with biochar amendments, especially with B500 and B700, contributing to the decreased N2O emissions. However, larger pore size of B500 and B700 (surface area of 68.1 and 161 m2 g− 1) than B300 (4.40 m2 g− 1) favored electron transfer between bacteria and iron minerals, leading to increased abundance of iron-reducing bacteria, (e.g., Clostridia, 48.2–50.6 vs. 33.3%), which competed with methanogens to produce CH4, thereby leading to lower increase in CH4 emission. Biochar amendments with high pH and surface area might be effective to mitigate emission of both N2O and CH4 from paddy soil.

Previous studies have shown that biochar enhances microbial reduction of iron (Fe) oxyhydroxide under anaerobic incubation. However, there is a lack of data on its influence on arsenic (As) release from As-contaminated paddy soils. In this study, paddy soil slurries (120 mg As kg −1 ) were incubated under anaerobic conditions for 60 days with and without the addition of biochar (3%, w/w) prepared from rice straw at 500 °C. Arsenic release, Fe reduction, and As fractionation were determined at 1, 10, 20, 30, and 60 d, while Illumina sequencing and real-time PCR were used to characterize changes in soil microbial community structure and As transformation function genes. During the first month of incubation, As released into soil solution increased sharply from 27.9 and 55.9 to 486 and 630 μg kg −1 in unamended and biochar amended slurries, with inorganic trivalent As (As III ) being the dominant specie (52.7–91.0% of total As). Compared to unamended slurries, biochar addition increased As and ferrous ion (Fe 2+ ) concentrations in soil solution but decreased soil As concentration in the amorphous Fe/Al oxide fraction (F3). Difference in released As between biochar and unamended treatments ( Δ As) increased with incubation time, showing strong linear relationships (R 2 = 0.23–0.33) with Δ Fe 2+ and Δ F3, confirming increased As release due to enhanced Fe reduction. Biochar addition increased the abundance of Fe reducing bacteria such as Clostridum (27.3% vs. 22.7%), Bacillus (3.34% vs. 2.39%), and Caloramator (4.46% vs. 3.88%). In addition, copy numbers in biochar amended slurries of respiratory As reducing ( arrA ) and detoxifying reducing genes ( arsC ) increased 19.0 and 1.70 fold, suggesting microbial reduction of pentavalent As (As V ) adsorbed on Fe oxides to As III , further contributing to increased As release.

BDET might be effective for the patients with OME, and proved to be an efficacious and mini-invasive treatment for OME.To evaluate the therapeutic benefits of balloon dilation eustachian tuboplasty (BDET) in the treatment of adult patients with otitis media with effusion (OME) caused by eustachian tube dysfunction (ETD).After informed consent, eight adult patients with OME were included in this study. After investigated patients' case history and oto-function, all patients underwent BDET treatment. Then four criteria including tympanic membrane, pure tone audiometry (PTA), tympanometry, and subjective symptoms were adopted to evaluate the therapeutic benefits of BDET.None of the involved patients complained of problems or complications during the post-operative period, or with absence of pain and bleeding after the operation. Prominent post-operative improvement was observed in tympanic membrane and otoscopic appearance. In addition, cure rates after 3 months and 6 months post-operatively were gradually increased.

Pollution controls were implemented to improve the air quality for the 2014 Youth Olympic Games (YOG) in Nanjing. To investigate the influence of pollution control on Pb inhalation bioaccessibility in PM2.5, samples were collected before, during, and after YOG. The objectives were to identify Pb sources in PM2.5 using stable isotope fingerprinting technique and compare Pb inhalation bioaccessibility in PM2.5 using two simulated lung fluids. While artificial lysosomal fluid (ALF) simulates interstitial fluid at pH 7.4, Gamble's solution simulates fluid in alveolar macrophages at pH 4.5. The Pb concentration in PM2.5 samples during YOG (88.2 ng m−3) was 44–48% lower than that in non-YOG samples. Based on stable Pb isotope ratios, Pb in YOG samples was mainly from coal combustion while Pb in non-YOG samples was from coal combustion and smelting activities. While Pb bioaccessibility in YOG samples was lower than those in non-YOG samples (59–79% vs. 55–87%) by ALF, it was higher than those in non-YOG samples (11–29% vs. 5.3–21%) based on Gamble's solution, attributing to the lower pH and organic acids in ALF. Different Pb bioaccessibility in PM2.5 between samples resulted from changes in Pb species due to pollution control. PbSO4 was the main Pb species in PM2.5 from coal combustion, which was less soluble in ALF than PbO from smelting activities, but more soluble in Gamble's solution. This study showed it is important to consider Pb bioaccessibility during pollution control as source control not only reduced Pb contamination in PM2.5 but also influenced Pb bioaccessibility. Keywords: Pb, Inhalation bioaccessibility, PM2.5, Stable isotope, Gamble's solution, Coal combustion

To evaluate the effect of different designs of marginal preparation on stress distribution in the mandibular premolar restored with endocrown using three-dimensional finite element method.Four models with different designs of marginal preparation, including the flat margin, 90° shoulder, 135° shoulder and chamfer shoulder, were established to imitate mandibular first premolar restored with endocrown. A load of 100 N was applied to the intersection of the long axis and the occlusal surface, either parallel or with an angle of 45° to the long axis of the tooth. The maximum values of Von Mises stress and the stress distribution around the cervical region of the abutment and the endocrown with different designs of marginal preparation were analyzed.The load parallel to the long axis of the tooth caused obvious stress concentration in the lingual portions of both the cervical region of the tooth tissue and the restoration. The stress distribution characteristics on the cervical region of the models with a flat margin and a 90° shoulder were more uniform than those in the models with a 135° shoulder and chamfer shoulder. Loading at 45° to the long axis caused stress concentration mainly on the buccal portion of the cervical region, and the model with a flat margin showed the most favorable stress distribution patterns with a greater maximum Von Mises stress under this circumstance than that with a parallel loading. Irrespective of the loading direction, the stress value was the lowest in the flat margin model, where the stress value in the cervical region of the endocrown was greater than that in the counterpart of the tooth tissue. The stress level on the enamel was higher than that on the dentin nearby in the flat margin model.From the stress distribution point of view, endocrowns with flat margin followed by a 90° shoulder are recommended.

Lead is a cumulative toxicant, which can induce severe health issues, especially in children’s case due to their immature nervous system. While realizing large-scale monitoring of children blood lead remains challenging by utilizing traditional methods, it is highly desirable to search for alternative techniques or novel sensing materials. Here we report a label-free and portable aptasensor based on graphene field effect transistor (FET) for effective children blood lead detection. With standard solutions of different Pb2+ concentrations, we obtained a dose-response curve and a detection limitation below 37.5 ng/L, which is three orders lower than the safe blood lead level (100 μg/L). The devices also showed excellent selectivity over other metal cations such as, Na+, K+, Mg2+ and Ca2+, suggesting the capability of working in a complex sample matrix. We further successfully demonstrated the detection of Pb2+ ions in real blood samples from children by using our aptasensors and explored their potential applications for quantification. Our results underscore such graphene FET aptasensors for future applications on fast detection of heavy metal ions for health monitoring and disease diagnostics.

Background To investigate the physical properties and the hydration behaviour of the fast-setting bioceramic iRoot FS Fast Set Root Repair Material (iRoot FS) and three other endodontic cements. Methods iRoot FS, Endosequence Root Repair Material Putty (ERRM Putty), gray and white mineral trioxide aggregate (G-MTA & W-MTA), and intermediate restorative material (IRM) were evaluated. The setting time was measured using ANSI/ADA standards. Microhardness was evaluated using the Vickers indentation test. Compressive strength and porosity were investigated at 7 and 28 days. Differential scanning calorimetry (DSC) was employed for the hydration test. Results iRoot FS had the shortest setting time of the four bioceramic cements (p

Using in vitro bioaccessibility assays to predict Pb relative bioavailability (RBA) in contaminated soils has been demonstrated, however, limited research was performed on urban soils having lower Pb levels. In this study, 162 soils from urban parks in 27 capital cities in China were measured for Pb bioaccessibility using the SBRC assay, with Pb-RBA in 38 subsamples being measured using a mouse-kidney assay. Total Pb concentrations in soils were 9.3-1198 mg kg-1, with 92% of the soils having Pb concentrations 100 mg kg-1. On the basis of a stable isotope fingerprinting technique, coal combustion ash was identified as the major Pb source, contributing to the increased Pb bioaccessibility with increasing soil Pb concentration. Lead-RBA in soils was 17-87%, showing a strong linear correlation with Pb bioaccessibility (r2 = 0.61), with cross validation of the correlation based on random subsampling and leave-one-out approaches yielding low prediction errors. On the basis of the large sample size of 38 soils, this study demonstrated that the Pb-RBA predictive capability of the SBRC assay can be extended from mining/smelting impacted soils to urban soils with lower Pb levels. Refereed/Peer-reviewed

Agarose gel electrophoresis (AGE) is one of the low-cost and large-scale separation techniques for the separation of metallic single-walled carbon nanotubes (m-SWCNTs) and semiconducting single-walled carbon nanotubes (s-SWCNTs). The separated m-SWCNTs were divided into several parts and characterized by the UV-visible-near infrared absorption spectra and the Raman spectra respectively. The results show that the moieties with the fastest electrophoresis migration rate contain more m-SWCNTs. Furthermore, the effects of different agarose concentrations on the separation efficiencies of SWCNTs were investigated. It was found that higher concentration of agarose gel was beneficial to the enrichment of the m-SWCNTs, and the separation efficiency of the m-SWCNTs could be realized by increasing the charge density on the surface of the SWCNTs.

Root proliferation can be stimulated in a heterogeneous nutrient patch; however, the functions of the root proliferation in the nutrient-rich soil patches are not fully understood. In the present study, a two-year field experiment was conducted to examine the comparative effects of localized application of ammonium and phosphorus (P) at early or late stages on root growth, nutrient uptake, and biomass of maize ( Zea mays L.) on a calcareous soil in an intensive farming system. Localized supply of ammonium and P had a more evident effect on shoot and root growth, and especially stimulated fine root development at the early seedling stage, with most of the maize roots being allocated to the nutrient-rich patch in the topsoil. Although localized ammonium and P supply at the late stage also enhanced the fine root growth, the plant roots in the patch accounted for a low proportion of the whole maize roots in the topsoil at the flowering stage. Compared with the early stage, fine root length in the short-lived nutrient patch decreased by 44%–62% and the shoot dry weight was not different between heterogeneous and homogeneous nutrient supply at the late growth stage. Localized supply of ammonium and P significantly increased N and P accumulation by maize at 35 and 47 days after sowing (DAS); however, no significant difference was found among the treatments at 82 DAS and the later growth stages. The increased nutrient uptake and plant growth was related to the higher proportion of root length in the localized nutrient-enriched patch. The results indicated that root proliferation in nutrient patches contributed more to maize growth and nutrient uptake at the early than late stages.

Objective To assess the three dimensional (3D) accuracy of deciduous tooth surface model reconstruction from cone-beam CT(CBCT) scans using image superimposition method. Methods 14 sound extracted human deciduous teeth were scanned by micro-CT and CBCT scanner. The digital tooth models reconstructed from CBCT scans were superimposed onto the standard model from micro-CT scans respectively. Distribution patterns of shape discrepancy were presented using histogram, as well as shown in different colors on the superimposed images. The voluminal discrepancy versus the volume of the standard image (RVD/VS) were calculated and analyzed, using t test. Results There was no statistically significant difference between deciduous anterior teeth and molars(P>0.05). The mean RVD/VS of digital tooth images obtained by CBCT scans was 3.932±4.038%, and significant difference were found (P

To decrease short-circuit current, adjusting the power network operation by breaking transmission lines is the most economic and convenient measure. For large power grid, breaking transmission lines has thousands of combinations, so it's very difficult to find the best combination in a short time. Firstly, this paper formulated the sensitivity relationship between transmission line outage and impedance change. Then preliminary combinations schemes of transmission line outage were selected according to the sensitivity. Index values of factors were given using the fuzzy control evaluation. Finally, this paper determined optimal scheme from maximum priority and accomplished the accessorial intelligent optimize system of limiting short-circuit current. The rapidity and rapidity of the proposed control strategy was verified by calculating the actual power grid.

Cylindrical shells are widely used in civil engineering. Examples include cooling towers, nuclear containment vessels, metal silos and tanks for storage of bulk solids and liquids, and pressure vessels. Cylindrical shells subjected to non-uniform wind pressure display different buckling behaviours from those of cylinders under uniform external pressure. At different aspect ratios, quite complex buckling modes occur. The geometric nonlinearity may have a significant effect on the buckling behavior. This paper presents a widely study of the nonlinear buckling behavior of cylindrical shells of uniform thickness under wind loading. The finite element analyses indicate that for stocky cylinders, the nonlinear buckling modes are the circumferential compression buckling mode, which is similar to cylinders under uniform external pressure, while for cylinders in mediate length, pre-buckling ovalization of the cross-section has an important influence on the buckling strength.

This paper focuses on a new type of 8-roll cold rolling mill with the back-up bearing roll. Compared to the traditional 6-roll cold rolling mill, a thick-walled bearing roll is used to multi-support the intermediate roll. By the rack, the fan-shaped gears, the eccentric core shaft and the servo-cylinder, the work roll can be pushed down by this screw down device on the top of the mill; By contrast with the 4(6)-roll mill, this type of mill has some characteristics, such as: the small size of rolls, lighter weight, the fast response for the screw down. The bearing roll is fixed by the supporting blocks placed on the rolling-mill housing. So this mill has large traverse rigidity, and this is propitious to the flatness control. By different means of strip flatness adjustments, such as the intermediate roll shifting, the roll bending and the bearing roll adjusting, the strip flatness can be well controlled. The oil-gas lubrication is used in the bearings of the bearing rolls, and the changing rolls equipment is designed for this type of mill too. A series of this type of mills (as 450, 800, 1250, 1450 series) have been produced since it was developed in 1997. The mills for 1250 and 1450 series have been applied in five-stand cold rolling mill and single stand reversing mill, a rolling speed of 800m/min has been achieved.

The existing research on flange focused on bearing capacity, and there were few reports on the rigidity of flange. In this paper, rigidity test was carried on for the connection of rigid flange and flexible flange in power-transformed frames. According to the test results, the axial rigidity, shear rigidity and flexural rigidity was compared. The results indicated that the axial rigidity, shear rigidity and flexural rigidity of flexible flange connection was lower than those of rigid flange connection for both the plain bolt and high strength bolt.

Test items include compressive strength, anti-breaking strength and split strength of standard concrete, rubber concrete and fiber-rubber concrete, and 43 groups test were conducted. In order to investigate the influence of the synergistic reaction between fiber and rubber powder on force-bearing performance of concrete used in subgrade, and different blended ratio effect on strength and extension of concrete were studied. The results indicated that with the increasing of content of 40 mesh rubber powder, the compressive strength of concrete decreasing regularly; with adding the blends of fiber and rubber powder, the anti-breaking strength and extension of concrete were promoted, as to fiber - 40 mesh rubber powder concrete, the content of rubber control less than 6%, and the fiber less than 0.5%，as to 60 mesh rubber powder -10mm fiber concrete, the content of rubber control less than 6%, and the fiber less than 0.5%; as to 60 mesh rubber powder -20mm fiber concrete, the appropriate adding quantity of rubber less than 2%, and the fiber less than 0.5%.

Microbial ferric iron reduction, with organic carbon or hydrogen as the electron donor, is one of the most important biogeochemical processes in anoxic paddy soils; however, the diversity and community structure of hydrogen-dependent dissimilatory iron-reducers remain unknown. Potential H2-dependent Fe(III)-reducing bacteria in paddy soils were explored using enrichment cultures with ferrihydrite or goethite as the electron acceptor and hydrogen as the electron donor. Terminal restriction fragment length polymorphism (T-RFLP) analysis and cloning/sequencing were conducted to reveal bacterial community structure. Results showed that Geobacter and Clostridium were the dominant bacteria in the enrichment cultures. Fe(III) oxide mineral phases showed a strong effect on the community structure; Geobacter and Clostridium were dominant in the ferrihydrite treatment, while Clostridium spp. were dominant in the goethite treatment. These suggested that H2-dependent Fe(III)-reducing bacteria might be widely distributed in paddy soils and that besides Geobacter, Clostridium spp. might also be an important group of H2-dependent Fe(III)-reducing microorganisms.

Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (63 μm) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous.

Four different types of full-scale slotted end plate (SEP) connection joints are tested to determine their failure modes and damage mechanisms under ultimate load, also analyze their force-displacement behaviors and developing processes of deformation and stress. The results show that ultimate bearing capacity of the I-type SEP joint is only approximate 1/2 of the other three types of SEP joints, which indicate the SEP’s type have great influence on the ultimate strength of joints. The instability of SEP is the main factor to cause the loss of bearing capacity of the connection joints, which is shown through the development of stress, that SEP enters into plastic stage and the other regions still are elastic.

Based on the experiment,the forming properties of Aluminum alloy in liquid forging was studied by adding rare-earth metal Y (Yttrium) modificatior and ternary modificatior(25% NaF +62% NaCl +13% KCl).The structure and mechanical properties of the prepared samples under two modifications were compared.The results showed that the rare-earth metal Y can modificatior liquid aluminum alloy forging a comprehensive mechanical properties of a substantial increase, the use of rare-earth metal Y (Yttrium)modificatior was better than ternary modificatior.