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The kinetics of isothermal austenite (γ)-to-ferrite (α) transformation at various temperatures in Fe–2Mn and Fe–2Mn–0.5Mo (wt%) alloys is investigated via dilatometry experiments and phase-field modeling. It was interestingly found that Mo addition has a marginal effect on the transformation kinetics. Besides the well-known partitioning and partitionless transformation modes, a new kinetic mode, in which interface migration is controlled by interfacial diffusion, was identified. The phase-field model with considering interfacial segregation could well predict the transformation kinetics and the kinetic mode transition.

Aerodynamic noise generated by 1:8 scale three carriages high-speed train was investigated by numerical simulation and wind tunnel test. The difference of far-field noise below 1600 Hz between simulation based on dense mesh and test is less than 3 dB(A), which indicates that the current simulation method has reasonable accuracy. It is found that dipole source can be used as the only sound source to calculate the far-field noise because its intensity is more significant than that of the quadrupole source. The subdomain method is applied to investigate the noise contribution and coherence analysis of full-scale head shape. It is found that the far-field noise contributions of the frame, bogie cavity and wheel set are significant, and the peak frequency occurs at the frequency of 630 Hz. Coherence analysis indicates that the far-field noise with the train body as the sound source has a relatively high correlation with the pressure pulsation caused by the vortex structure generated at the wiper housing and the bogie. Also, the side vortex near the front wheel has a higher correlation with the far-field noise at a higher frequency, while a stronger correlation between that near the rear wheel and the far-field noise occurs at a lower frequency.

The service performance of heat resistance steels is largely determined by the precipitation kinetics. The nucleation–growth–coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-term aging at 650 °C have been systemically investigated. The microstructural characteristics, precipitate morphology and alloying element distribution were studied by scanning electron microscopy, transmission electron microscopy and scanning transmission electron microscopy. The lognormal distribution fitting combined with the multiple regression analysis was adopted to evaluate the precipitate size distributions. Laves phase has longer incubation time, and its coarsening rate is almost one order of magnitude higher in comparison with that of M23C6carbide. Furthermore, the nucleation rate, number density, average radius, and volume fraction of two precipitates are simulated based on the classical nucleation theory and the modified Langer-Schwartz model. The precipitation behavior of Laves phase can be well explained with the Fe–W system as the interfacial energy takes 0.10 J/m2. In contrast, the simulation results of M23C6carbide in the Fe–Cr–C system are significantly overestimated, which results from the inhibitory effect of boron on coarsening.

The aim of this study was to evaluate left ventricular (LV) myocardial involvement in connective tissue disease (CTD) patients using multiparemetric imaging derived from cardiovascular magnetic resonance (CMR). CMR was performed on 146 CTD patients (comprising of 74 with idiopathic inflammatory myopathy (IIM) and 72 with non-IIM) and 72 healthy controls and included measures of LV global strains [including peak strain (PS), peak systolic (PSSR) and diastolic strain rate (PDSR)], myocardial perfusion [including upslope, max signal intensity (MaxSI), and time to maximum signal intensity (TTM)], and late gadolinium enhancement (LGE) parameters. Univariable and multivariable linear regression analyses were performed to determine the association between LV deformation and microvascular perfusion, as well as LGE. Our results indicated that CTD patients had decreased global longitudinal PS (GLPS), PSSR, PDSR, and myocardial perfusion (all p < 0.017) compared with normal controls. Non-IIM patients exhibited lower LV global strain and longer TTM than IIM patients. The presence of LGE was independently associated with global radial PS (GRPS: β = − 0.165, p = 0.011) and global circumferential PS (GCPS: β =  − 0.122, p = 0.022). TTM was independently correlated with GLPS (β = − 0.156, p = 0.027). GLPS was the best indicator for differentiating CTD patients from normal controls (area under curve of 0.78). This study indicated that CTD patients showed impaired LV global myocardial deformation and microvascular perfusion, and presence of LGE. Cardiac involvement might be more severe in non-IIM patients than in IIM patients. Impaired microvascular perfusion and the presence of LGE were independently associated with LV global deformation.

Based on mechanism of ECH (Electrocatalytic Hydrogenation),the Pa/PPy/Foam-Ni (Pd/PPY/Ni) prepared by electrical depositing was used as cathode to detoxifythree kinds of dichlorophenol (DCP) and improve their biodegradability. According to the dechloridation ability of electrodes prepared under different conditions, the factors were optimized. The removal efficiency of 2,4-dichlorophenol（2,4-DCP）reaches 64.45% when the supporting electrolyte is p-toluenesulfonic acid and the voltage is 0.6V and polymerizing time is 20mins. Analyzing the photograph from SEM (Scanning Electron Microscope), it shows that PPy (PolyPyrrole) changes depositing properties of Pa on foam-Ni substrate, which increases specific surface area and special ductility so as to benefit Pd to deposite on Ni substrate and improve ECH.

The sulfate reducing bacteria (SRB) bactericide was synthesized using KNO3, isothiazolinone, quaternary ammonium salt, and additives as main components, and the optimal ratio and critical concentration of the bactericide were determined. Weight loss method, potentiodynamic polarization curve, compatibility study were used to investigate the changes of corrosion rate and corrosion current density and compatibility after adding the bactericide. The results showed that the optimal formula ratio of the bactericide was: KNO3: isothiazolinone: quaternary ammonium salt: additive is 20:1:2:3, and the critical concentration of the bactericide was 50 mg/L. The addition of bactericides reduced the corrosion rate of pipes by 67% to 88%, and the electrochemical corrosion current density of pipes was significantly reduced, indicating that the presence of bactericides under the given media conditions significantly slowed down the corrosion process of metals. The bactericide was used in conjunction with commonly used oilfield chemicals such as corrosion inhibitors, scale inhibitors, flocculants, without obvious changes in appearance, no reduction in efficacy. Therefore, it may be concluded that the bactericide has good compatibility.

The influence of temperature, flow rate, PH value, and oxygen content on the corrosion law in the carbon dioxide salt solution of J55 oil casing was investigated by the corrosion weight loss method. The results showed that with the increase of temperature, the corrosion rate of J55 steel first increased and then decreased and the corrosion rate reached the maximum at 100°C. The corrosion rate was closely related to the formation of corrosion products. The increase of the flow rate speeded up the transfer rate of the corrosive medium to the metal surface and hindered the formation of FeCO3 on the metal surface. The corrosion rate was significantly higher than the corrosion rate under static conditions, and as the flow rate increased, the corrosion rate of J55 steel increased accordingly. The increase of the pH value gradually reduced the concentration of hydrogen ions, and cathodic reaction of hydrogen ion depolarization during metal corrosion process was inhibited, and the tendency to form an oxidizing protective film on the surface of carbon steel increased, thereby reducing the corrosion rate of metals. With the increase of oxygen content, there were both hydrogen evolution reaction of CO2 and oxygen absorption reaction caused by O2 in the cathode process. The corrosion rate of J55 steel gradually increased, and at the same oxygen content, the higher the carbon dioxide content, the greater the corrosion rate is.

Commercial F91 steel was exposed to atmospheric pressure CO2 and laboratory air at 550 °C for exposure times up to 1000 h. In both atmospheres, a Fe-rich duplex oxide scale formed, but with different morphology, oxide phases and growth rates. In CO2, the duplex morphology was observed at the onset of oxidation and it was found that the cooling rate affect the oxide phases formed on the outer scale. In air, the alloy initially formed a protective chromium rich oxide layer, followed by the nucleation and growth of duplex iron-rich oxide nodules at random locations, leading to breakaway oxidation. Alloy carburization was also observed in CO2 but not in air environment.

Microstructure evolution or degradation has been well recognized to be closely related to the formation of microcracks in pearlitic rails and wheels. The rolling contact fatigue machine was employed to simulate the rail–wheel contact, and the microstructure evolution and crack formation of pearlitic steels subjected to rolling–sliding contact loading were then experimentally characterized. To further quantitatively predict the fracture behaviors, a phase-field model was herein established to investigate the cyclic loading-driven microstructure evolution and the microstructure-dependent fracture resistance in pearlite. The coupling of microstructure evolution and crack propagation was realized through the introduction of two-set order parameters, i.e., the crack field and the microstructure field, and the microstructure-dependent fracture toughness. The proposed model can predict the fracture resistance of microstructure at different depths from the contact surface, after different rolling cycles and with different initial pearlitic microstructures, which can shed light on the design of damage-resistant microstructure of pearlitic steels.

The investigated alloys are newly developed Tribaloy alloys with enhanced crack and oxidation resistance over the traditional Tribaloy alloys. The cyclic oxidation performance and effects of complex oxides on the hardness of cobalt-based Tribaloy alloys T-401 (hypoeutectic) and T-900 (hypereutectic) were assessed. The results showed that T-900 alloy has a lower oxidation rate as compared to T-401 alloy at 800 and 1000 °C, which attributed to the formation of dense continuous Cr2O3layer with an upper thinner continuous layer of CoCr2O4and NiCr2O4oxides. At 1000 °C, T-401 alloy exhibited poor oxidation resistance due to severe spallation after 3 cycles (45 h). After oxidation, T-900 alloy exhibits 98% and 18% lower mass gain than T-401 alloy at 1000 and 800 °C, respectively. For T-900 alloy, relationship between mass gain and thickness of oxide layer revealed that mass will increase 0.162 mg/cm2for every 1-µm increase in the oxides thickness. Internal SiO2oxide was observed at 800 and 1000 °C for both alloys. However, the extent of internal Si oxides increased with increasing oxidation temperature from 800 to 1000 °C. Consequently, internal oxidation of Si led to the formation of Laves phase-depleted region near oxide/alloy interface in T-900 alloy at 1000 °C. Thus, hardness of T-900 alloy decreased from 618 to 392 HV beneath the oxide/alloy interface at 1000 °C, whereas hardness of T-900 and T-401 alloys after cyclic oxidation test at 800 °C increased from 618 to 855 and 519 to 685 HV, respectively.

A numerical investigation of flow past a square cylinder with a circular bar upstream and a splitter plate downstream is carried out in this paper by lattice Boltzmann method (LBM). The combination of the three obstacles and LBM is the main novelty of the present study. The flow patterns are analyzed by a uniform flow of Reynolds number 100 based on the side length of the square cylinder, D. Numerical simulations are performed in the range of 1 ≤ Ds/D≤ 5, 0 ≤ G/D≤ 7 and 1 ≤ L/D≤ 6, where Ds, Gand Lare the center-to center distance, surface-to-surface distance and the splitter plate length, respectively. Six flow patterns are observed in the present study. The maximum percentage reduction in mean drag coefficient is 68.76% at (ds, g, l) = (2.5, 0, 3) which is in pattern VI. The vortex shedding from the square cylinder and the circular bar can be completely suppressed in pattern VI. The small distance between the square cylinder and the splitter plate plays a more vital role in suppression of vortex shedding as compared with large distance and length.

Hot roll bonding was carried out between commercially pure titanium TA2 and high-strength low-alloy steel Q390 using no interlayer and Fe interlayer at temperatures of 850, 900, 950 and 1000 °C with a total reduction ratio of 86.7%. Interfacial microstructure and bonding property of clad plates were investigated by electron microscopy and shear test. The results showed that with the increase in heating temperature, the shear strength of titanium clad steel plates decreases obviously. Compared with that of titanium clad steel plates with no interlayer, inserting Fe interlayer between titanium and steel can improve the shear strength at 850 and 900 °C but deteriorate the shear strength at 950 and 1000 °C. The reason for this consequence was that Fe interlayer prevented the reaction diffusion of C in titanium to form a thinner TiC layer at 850 and 900 °C, while Fe interlayer promoted the reaction diffusion of Fe in titanium to generate thicker Fe2Ti and FeTi intermetallic compound layers at 950 and 1000 °C.

The oxidation behaviors of CrMoV, F91, and 310S alloys in CO2at 550 °C for up to 1000 h were studied by weight change measurements, scanning electron microscopy, X-ray diffraction, Raman microscopy, optical microscopy, and glow discharge optical emission spectroscopy. 310S showed the best oxidation resistance followed by F91 and then CrMoV. Both CrMoV and F91 formed a duplex oxide layer, consisted of Fe2O3, Fe3O4, and Fe–Cr spinel, while 310S formed NiFe2O4spinel and Cr2O3. Carburization was only observed in F91 and 310S alloys. The rates of metal loss were evaluated for long-term applications in power plants.

The service environment of Yanchang oilfield was researched. The corrosion environment of the oil and gas area of Yanchang group is different, the summer rainstorm is frequent and the landslide debris flow is easy to occur. The theoretical analysis and pilot test of pipeline performance have been carried out. We suggest that the steel pipeline, t FRP pipeline and the flexible composite pipe for high pressure transmission can be used in Yanchang group. The combined application strategy of steel pipeline, FRP pipeline and flexible composite pipe for high pressure transmission was proposed and verified. The results show that the combined application strategy effectively slows down the pipeline corrosion problem, reduces pipeline leakage accidents caused by accidental landslides, and reduces environmental pollution accidents caused by accidents such as pipeline corrosion and leakage. The tracking and analysis of pipeline combined application strategy for up to 5 years, the results show that the pipeline combined application strategy is more economical. It is concluded that the combined application strategy of steel pipelines, FRP pipelines and Flexible Composite Pipe for High Pressure Transmissions can ensure smooth operation of pipelines and save costs in the development of oil and gas fields, and it is recommended to popularize.

Cost factors must be considered in the development of Yan'an gas field. In order to evaluate the applicability of economical 80S steel in the sulfur gas reservoir environment of Yan'an gas field, the indoor corrosion test was conducted to evaluate the resistance of 80S steel to uniform corrosion and SCC resistance in CO2/H2S coexisting corrosion environment, and combined with relevant standards. The security was analyzed. The results show that the uniform corrosion rate of 80S steel is the largest at 50 °C, and it decreases first and then increases with the increase of temperature. When the loading stress is 496.8MPa (552MPa×90%),the test duration was 720h. One sample cracked and the other two parallel samples did not cracked Comprehensive anti-uniform corrosion performance and anti-SCC performance, it is believed that 80S steel has certain risks in the corrosive environment of Yan'an gas field. It needs to cooperate with other anti-corrosion measures and monitor the service of the well string at any time.

The corrosion resistance of P110S steel in CO2 and H2S coexistence corrosion environment under different temperature and PCO2/PH2S was investigated by high temperature and high pressure (HTHP) reaction kettle combined with SEM, EDS and XRD analysis methods. The stress corrosion cracking (SCC) resistance of P110S steel was studied under loading pressure of 682.2MPa (758MPa×90%) in simulated conditions after 720 hours test. The results show that the P110S steel has serious corrosion in the range of simulative temperature and H2S partial pressure. With the increase of temperature, the corrosion rate decreases first and then increases. With the increase of H2S partial pressure, the corrosion rate increases first and then decreases. The P110S steel has the highest corrosion rate when the temperature is 50 °C and H2S partial pressure is 0.1%. After the anti-SCC test, the specimens did not fracture, and cracks perpendicular to the tensile stress were not found on the surface. That is, P110S has good SCC resistance in the corrosive environment.

Hot roll bonding was carried out between commercially pure titanium TA2 and high-strength low-alloy steel Q390 using pure Nb or Mo interlayer at 950 °C with a total reduction ratio of 86.7%. Interfacial microstructure and bonding properties of titanium clad steel plates were investigated by electron microscopy and mechanical tests. The results showed β-Ti, TiC and Fe2Ti reaction phases were generated at Ti/steel interface for the clad plates with no interlayer. Inserting Nb or Mo interlayer can effectively suppress the formation of brittle phases, while the weak bonding joint transferred to Nb/steel or Mo/steel interface. And some micro-voids were found at the interface of Nb/steel and Mo/steel. The improved shear strength of clad plates with Nb interlayer might be attributed to the elimination of brittle phases at bonding interface. The small size and little quantities of the micro-voids at Nb/steel interface had a relatively weak effect on shear strength. However, the large number and big size of micro-voids were responsible for the degradation of shear strength for the clad plates with Mo interlayer.

As the increasing need of the steels with both high strength and hydrogen embrittlement resistance ability, carbide precipitation and element distribution in high Co–Ni secondary hardening steel were concerned. Carbide precipitation and element distribution in M54 were observed using carbon replicas method. Both simulation and observation results showed that MC and M2C formed in the steel. MC was round particle, which would act as grain refiners. And M2C was needle-like phase, which would be remarkable strengthening phases. Nb and V were main metallic elements in MC phase. Mo and Cr were main metallic elements in M2C phase. W, Co, and Ni were probably mainly dissolved in the matrix. As the carbide precipitation in AerMet100 was M2C, which had similar size and shape with M2C in M54, the tensile strength and yield strength of AerMet100 and M54 were similar. Compared with traditional high Co–Ni secondary hardening steel, M54 had higher hydrogen embrittlement resistance ability, probably because of element W in the matrix.

The different solution and migration behaviors of tetrahedral and octahedral interstitial helium in bcc iron have been investigated by using first principles calculations. We showed that the tetrahedral site has less charge transfer and less redistribution of the density of states but stronger bonding and a lower solution energy. This is due to the coupling between the symmetrical facts of the two interstitial atoms and the 3dorbitals of Fe atoms. The solution energies of both sites are not significantly influenced by applied normal strains of 2% and 4%. In contrast, the migration barriers have the reverse trends for different migration directions under strain, which can be explained by an anisotropic elastic energy change and charge transfer. The lower migration energy along certain directions under strain can facilitate the segregation of helium and the formation of helium bubbles.

Morphology observation and crystallographic analysis of lath martensite in 13Cr-5Ni steel were investigated by electron backscattering diffraction (EBSD) in a scanning electron microscope. The pole figures of the microstructure measured by EBSD showed that the martensite in this steel held the Kurdjumov–Sachs (K–S) orientation relationship, and the boundary misorientations after the austenite–martensite transformation were also analyzed. However, not all the 24 possible variants in the K–S relationship were observed in a single prior austenite grain. Sub-blocks with special combinations were observed, which can be explained by the minimization of the total shape strain between the adjacent variants introduced during the martensite transformation and relatively low carbon content in the 13Cr-5Ni steel.

To evaluate the association between IL-6 in prostatic tissue/blood sample and BPH-LUTS, so as to preliminarily discover an indicator of inflammation that could show the severity of LUTS.

Three kinds of high Co-Ni secondary hardening steels with different Ni contents were studied. The nanoscale austenite layers formed at the interface of matensite laths were observed. Both observation and diffusion kinetic simulation results showed that both Ni and Co did not obtain enough time to get the equilibrium content in this system. The Ni content in austenite layers decreased significantly, and Co content increased slightly with the decrease of Ni content in overall composition. The austenite stability was estimated by Olson-Cohen model, in which both chemical and mechanical driving force could be calculated by equilibrium thermodynamic and Mohr's circle methods, respectively. Simulation and mechanical test results showed that the decrease of Ni content in austenite layers would cause the change of austenite stability and decrease the fracture toughness of the steels. When the Ni content in the overall composition was lower than 7 wt. %, the Ni content in yphase would be lower than 20 wt. %.And the simulation value of Msσ(stress-induced critical martensite transformation temperature) would be up to 80 °C, which was about 60 °C higher than room temperature. Based on the analysis, the Ni content in the overall composition of high Co-Ni secondary hardening steels should be higher than 8 wt. %in order to obtain a good fracture toughness.

Three kinds of high Co-Ni secondary hardening steels with different Ni contents were studied. The nanoscale austenite layers formed at the interface of matensite laths were observed. Both observation and diffusion kinetic simulation results showed that both Ni and Co did not obtain enough time to get the equilibrium content in this system. The Ni content in austenite layers decreased significantly, and Co content increased slightly with the decrease of Ni content in overall composition. The austenite stability was estimated by Olson-Cohen model, in which both chemical and mechanical driving force could be calculated by equilibrium thermodynamic and Mohr’s circle methods, respectively. Simulation and mechanical test results showed that the decrease of Ni content in austenite layers would cause the change of austenite stability and decrease the fracture toughness of the steels. When the Ni content in the overall composition was lower than 7 wt. %, the Ni content in γphase would be lower than 20 wt. %. And the simulation value of $M_{\rm{S}}^\sigma $(stress-induced critical martensite transformation temperature) would be up to 80 °C, which was about 60 °C higher than room temperature. Based on the analysis, the Ni content in the overall composition of high Co-Ni secondary hardening steels should be higher than 8 wt. % in order to obtain a good fracture toughness.

Due to the heterogeneity of anatomic anomalies in Ebstein's anomaly (EA), particularly in the subset of patients with atrial septal defect (ASD), hemodynamic changes, which ultimately cause left ventricular (LV) deterioration remain unclear. The current study aimed to investigate the effect of concomitant ASD on LV function using cardiovascular magnetic resonance (CMR) imaging in patients with EA.

To study the microstructural evolution of pearlite steel subjected to pure rolling and rolling-sliding contact loading, a hypoeutectoid pearlite steel with composition and microstructure similar to BS11 was designed and twin-disc tests of this pearlite steel were performed to simulate the wheel/rail system. After a series of twin-disc tests, optical microscope (OM) observation, scanning electron microscope (SEM) observation, X-ray diffraction (XRD), and micro-hardness tests were conducted to characterize the microstructure. Under the pure rolling contact condition, a large amount of reticular cracks emerged within 60 μm below the contact surface of the samples after 120000 revolutions. The largest deformation was approximately 200 μm below the contact surface. Under the rolling-sliding contact condition, the nodularization of pearlite within 100 μm below the contact surface was obvious. The microstructure and stress-strain distribution of the area within 2 mm below the contact surface were investigated. The distribution of micro-hardness under the contact surface varied with contact conditions. Finite element method (FEM) was used to simulate the stress-strain distribution. The results of SEM, FEM, and micro-hardness tests indicated that under the pure rolling contact condition, the maximum plastic strain was approximately 200–400 μm below the contact surface. Conversely, under the rolling-sliding contact condition, the maximum plastic strain emerged on the contact surface. Under the pure rolling contact condition, the distribution of micro-hardness was almost identical to that of the equivalent plastic strain. Under the rolling-sliding contact condition, the distribution of micro-hardness was affected by the equivalent plastic strain and tangential stress.

To study the microstructural evolution of pearlite steel subjected to pure rolling and rolling-sliding contact loading, a hypoeutectoid pearlite steel with composition and microstructure similar to BS11 was designed and twindisc tests of this pearlite steel were performed to simulate the wheel/rail system. After a series of twin-disc tests, optical microscope (OM) observation, scanning electron microscope (SEM) observation, X-ray diffraction (XRD), and micro-hardness tests were conducted to characterize the microstructure. Under the pure rolling contact condition, a large amount of reticular cracks emerged within 60 µm below the contact surface of the samples after 120 000 revolutions. The largest deformation was approximately 200 µm below the contact surface. Under the rolling-sliding contact condition, the nodularization of pearlite within 100 µm below the contact surface was obvious. The microstructure and stress-strain distribution of the area within 2 mm below the contact surface were investigated. The distribution of micro-hardness under the contact surface varied with contact conditions. Finite element method (FEM) was used to simulate the stress-strain distribution. The results of SEM, FEM, and micro-hardness tests indicated that under the pure rolling contact condition, the maximum plastic strain was approximately 200 – 400 µm below the contact surface. Conversely, under the rolling-sliding contact condition, the maximum plastic strain emerged on the contact surface. Under the pure rolling contact condition, the distribution of micro-hardness was almost identical to that of the equivalent plastic strain. Under the rolling-sliding contact condition, the distribution of micro-hardness was affected by the equivalent plastic strain and tangential stress.

The working conditions of the ceramic cores are extremely harsh with the development of the preparation technology and improvement of the use conditions in the hollow blades, which brings forward high request for the preparation and properties of the ceramic cores. In this paper, silica ceramic powders were firstly coated by the silicon resin. The obtained composite powders were used to prepare the ceramic cores by the dry pressing method. And the phase compositions, microstructure and properties of the ceramic cores with the sintering temperatures were investigated. The results showed that the composite powders prepared by the coating showed good formability. The sintering temperature promoted the formation of the cristobalite. With the increase of the sintering temperature, the porosity of ceramic cores gradually decreased, the shrinkage rate and bulk-density increased. The prepared ceramic cores at 1250°C had highest bend strength of 19.25Mpa.

A piezoelectric stack with its large output force and small displacement cannot satisfy the requirement of the opening of the cone valve core of the actual situation. Piezoelectric hydraulic actuator AMESIM model was established, and the influence on the output displacement and the driving force factors related to simulation and analysis was determined. The results show that the area of the piezoelectric stack has no effect on the output displacement of piezoelectric hydraulic actuator, but with the increase of the area of the maximum output of the piezoelectric hydraulic actuator drive led to nonlinear growth. In the simulation range of 0~60 Hz, the former has better vibration suppression effect than the latter. At some frequencies, the body vibration suppression ability can reach 6.4 times that of the latter.

In this paper, the textured Si3N4ceramics were prepared by adding seed particles during gel-casting in the magnetic field of 6 T, followed by pressureless sintering. The effect of pH on the stability and dispersibility of Si3N4slurry and the effect of seed particles content on texture formation of Si3N4ceramics were both studied. Those results showed that the slurry with good stability and dispersibility was obtained when pH was about 11.6. Theaor b-axis of Si3N4particles or crystals was aligned parallel to the direction of the magnetic field in the magnetic field of 6 T. The degree of texture of Si3N4ceramics further increased during sintering. With the increasing of additional β-Si3N4particles in the magnetic field of 6 T, the degree of texture increased from 0.19 without seed particles to 0.76 with 9% (mass fraction) seed particles. The increase of seed particles content promoted the texture formation of Si3N4ceramics.

In this study, the precipitation behavior of a new austenitic heat-resistant steel (Fe–20Cr–30Ni–2Nb, in at%) was investigated. The effects of alloying addition of boron (B) and lanthanum (La) on the microstructure of the austenitic steel were scrutinized using SEM, EPMA, TEM, and XRD. The results showed that the addition of B enhanced the precipitation of bar-type Laves phase. A small precipitate with high La concentration was observed at the grain boundary in the alloy without aging; similar precipitates without La also presented in region adjacent to the La single phase. This result indicates that La can exist independently and does not contribute to the formation of new compounds. However, in both B- and La-modified alloy, B appeared in the precipitate free zone. In the alloy containing both B and La, only Fe2Nb Laves-phase precipitates, as indicated by the XRD result.

By analyzing two Polycarboxylate cement admixture of different polymerization process adaptability, the cement paste experiment is carried out to show the influence of Polycarboxylate superplasticizer, slump agent and the cement synthesis process on cement adaptability. Through orthogonal design method, result is drawn from the comparison of the influence of initial liquidity and an hour liquidity under different conditions,which is base on treating Polymeric acid process parameters as effecting factor within a certain range. It is shown that the preferably optimized process parameters of Polycarboxylic acid exist in the same kind of cement.The system error caused by the impact of cement composition is indicated in different kinds of cement.The adaptability of Polycarboxylic acid cement admixture of the mother liquor is available in the process optimization of the parameters.

In this paper, the method to adjust the production process of polycarboxylic admixtures mother liquid is researched according to the production of polycarboxylic admixtures. One polycarboxylic admixture cannot be adapted to all cements because of the influence of the mother liquid, although it could be adjusted by composite stabilizer. This paper studies the method of parameter adjustment on the level of factor analysis according to the process of polycarboxylic admixtures. The fluidity of cement slurry test is carried out when the type of cement is changed. On the basis of the test results the parameters are analyzed to design the molecular structure of the polycarboxylic admixtures, which could solve the problem of compatibility between polycarboxylic admixture and cement fundamentally.

For the study of fracture characteristics of ultra-high performance cementitious composites(ECC),16 different sizes of three-point bending beams were made and ultimate load, ultimate deflection and crack mouth opening displacement ,the curve andcurve of ECC were contructed,with the method of fracture work recommendedby RILEM , the external work was respectively calculated by the curve ofand, which determined the fracture energy of ECC.Results show that two kinds of calculation result are roughly equal;The influence of size effect on fracture character was: fracture energy increased with the increasing of the crack-depth ratio, the fracture energy of concrete specimen is the maximum when the crack-depth ratio is 0.4 ; is proportional to the initial crack-depth of the specimen, but there is no relationship betweenand crack-depth ratio. This paper would have great significance for the study of fracture characteristics of ECC.

To compare the characteristics of tubercular vs. leukemic involvement of abdominopelvic lymph nodes using multidetector computed tomography (CT).

Most of studies on transcriptional regulation mainly focus on upstream regions of genes. More and more recent researches indicate that introns may have important biological functions in transcription regulation of genes. The characterization of words in DNA sequences can be facilitated by the sequences’ functions. Using U-score and Z-score statistic, respectively, we extracted some over-represented words in intron 1s of ribosomal protein genes. A majority of them are accordance with known transcriptional factor binding sites and are potential regulatory elements. And, the detected over-represented words are more likely to form wider potential sequences and are denser in intron 1s of RP genes. We speculate the properties of these words may be associated with the transcriptional regulation of RP genes.