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Maternal high-fat diet (HFD) is associated with metabolic syndrome and cardiovascular diseases in adult offspring. Our previous study demonstrated that maternal HFD enhances pressor responses to ANG II or a proinflammatory cytokine (PIC), which is associated with increased expression of brain renin-angiotensin system (RAS) components and PICs in adult offspring. The present study further investigated whether inhibition of angiotensin-converting enzyme (ACE) or tumor necrosis factor-α (TNF-α) blocks sensitization of ANG II hypertension in offspring of HFD dams. All offspring were bred from dams with normal fat diet (NFD) or HFD starting two weeks before mating and maintained until weaning of the offspring. Then the weaned offspring were treated with an ACE inhibitor (captopril) or a TNF-α inhibitor (pentoxifylline) in the drinking water through the end of testing with a slow-pressor dose of ANG II. RT-PCR analyses of the lamina terminalis and paraventricular nucleus revealed upregulation of mRNA expression of several RAS components and PICs in male offspring of HFD dams when compared with age-matched offspring of NFD dams. The enhanced gene expression was attenuated by blockade of either RAS or PICs. Likewise, ANG II administration produced an augmented pressor response in offspring of HFD dams. This was abolished by either ACE or TNF-α inhibitor. Taken together, this study provides mechanistic evidence and a therapeutic strategy that systemic inhibition of the RAS and PICs can block maternal HFD-induced sensitization of ANG II hypertension, which is associated with attenuation of brain RAS and PIC expression in offspring.

This paper describes a proper low cost way to fabricate defects free porous carbon preforms with interconnect pore structure for making reaction formed SiC (RFSC). Taking charcoal , poplar powder, camphene and polymer dispersant together, making slurries by milling under 55 °C for several hours, controlling the content of charcoal and poplar powder, after casting, sublimating and carbonizing, the porous carbon performs with a series density (0.66 g/cm3-0.78 g/cm3) and porosity (62.9 vol.%-68.6 vol.%) were prepared; through the Si infiltrating process under a vacuum condition (~5.0 Pa) at 1500°C for about 0.5 hour, the RFSCs with fine mechanic performance were fabricated, one RFSC sample has the density, Weibull modulus, and the max three points flexural strength is 2.91 g/cm3, 9.5 and 505.0 MPa respectively.

In this paper, high volume fraction SiCp/Al composite was fabricated by pressureless technique with silicon carbide porous preform which fabricated through gel casting process. The effects of solid loading on the rheological properties of SiC slurry were discussed. High solid loading SiC slurry of 65vol% with low viscosity and high stability was fabricated. Also microstructure, flexural strength of the SiC preform and SiCp/Al composite were studied, the results showed gel casting process and pressureless infiltration technique were suitable for fabricating high volume fraction, homogeneous structure and high performance SiCp/Al composite.

The 3D printing ceramic body was prepared by camphene carbon/silicon carbide slurry, which were prepared with camphene, carbon and silicon carbide, dispersant, binder as rawmaterial, according to certain stoichiometric ratio. The effects of the choice of dispersants on the dispersion of the slurry performance were investigated. The amount of dispersant were determined.

In this paper, high temperature multilayer thermal insulations were to investigate in thermal protection systems for hypersonic vehicles. The thermal response and thermal property of the multilayer insulations were simulated and analyzed by using Ansys software. The calculation results were analyzed and the effects of parameters such as layer thermal conductivity, layer thickness, layer density, and numbers of layer are clarified. Thermal property of multilayer insulations was optimized. The results are helpful to the optimum design of the multilayer insulation system.

CVD SiC material with many excellent physical and chemical properties was used widely in the field of aerospace as reflector materials. In addition, CVD SiC thin film materials because of its compact structure, high purity can also be used as precision optical components of semiconductor industry. But the CVD process is a complex chemical process and the reaction process is very time consuming. Research of chemical vapor deposition for preparing silicon carbide process mechanism is important significance for the expansion of the application of silicon carbide. In this paper, CVD SiC coatings were fabricated by the pyrolysis of methyltrichlorosilane (MTS) in hydrogen at a low pressure. XRD and EDS were used to characterize the component of intermediate. SEM was used to observe the surface morphology and microstructure of coatings. The results indicated that key problem to be solved is to control the growth rate of SiC for high quality deposition coating, while the growth rate is also affected by process parameters. To obtain the materials to meet the use requirements, the need for control of each parameter in the reaction process.

Accumulating evidence indicates that maternal high-fat diet (HFD) is associated with metabolic syndrome and cardiovascular disease in adult offspring. The present study tested the hypothesis that maternal HFD modulates the brain renin-angiotensin system (RAS), oxidative stress, and proinflammatory cytokines that alter angiotensin II (ANG II) and TNF-α actions and sensitize the ANG II-elicited hypertensive response in adult offspring. All offspring were cross fostered by dams on the same or opposite diet to yield the following four groups: offspring from normal-fat control diet-fed dams suckled by control diet-fed dams (OCC group) or by HFD-fed dams (OCH group) and offspring from HFD-fed dams fed a HFD suckled by control diet-fed dams (OHC group) or by HFD-fed dams (OHH group). RT-PCR analyses of the lamina terminalis and paraventricular nucleus indicated upregulation of mRNA expression of several RAS components, NADPH oxidase, and proinflammatory cytokines in 10-wk-old male offspring of dams fed a HFD during either pregnancy, lactation, or both (OHC, OCH, and OHH groups). These offspring also showed decreased cardiac baroreflex sensitivity and increased pressor responses to intracerebroventricular microinjection of either ANG II or TNF-α. Furthermore, chronic systemic infusion of ANG II resulted in enhanced upregulation of mRNA expression of RAS components, NADPH oxidase, and proinflammatory cytokines in the lamina terminalis and paraventricular nucleus and an augmented hypertensive response in the OHC, OCH, and OHH groups compared with the OCC group. The results suggest that maternal HFD blunts cardiac baroreflex function and enhances pressor responses to ANG II or proinflammatory cytokines through upregulation of the brain RAS, oxidative stress, and inflammation. NEW & NOTEWORTHY The results of our study indicate that a maternal high-fat diet during either pregnancy or lactation is sufficient for perinatal programming of sensitization for hypertension, which is associated with hyperreactivity of central cardiovascular nuclei that, in all likelihood, involves elevated expression of the renin-angiotensin system, NADPH oxidase, and proinflammatory cytokines. The present study demonstrates, for the first time, the central mechanism underlying maternal high-fat diet sensitization of the hypertensive response in adult offspring.

Accumulating evidence indicates that maternal high fat diet (HFD) is associated with metabolic syndrome and cardiovascular disease in adult offspring. The present study tested the hypothesis that maternal HFD modulates the brain renin-angiotensin system (RAS), oxidative stress and proinflammatory cytokines that alters angiotensin II and tumor necrosis factor-α (TNF-α) actions to sensitize the angiotensin II-elicited hypertensive response in adult offspring. All offspring were cross-fostered by dams on the same or opposite diet to yield 4 groups: offspring from normal fat control diet (CD)-fed dams suckled by CD-fed dams (OCC) or by HFD-fed dams (OCH) and offspring from HFD-fed dams fed HFD suckled by CD-fed dams (OHC) or by HFD-fed dams (OHH). RT-PCR analyses of the lamina terminalis (LT) and paraventricular nucleus (PVN) indicated upregulation of mRNA expression of several RAS components, NADPH oxidase and proinflammatory cytokines in 10-week old male offspring of dams fed HFD during either pregnancy, lactation or both (OHC, OCH and OHH). These offspring also showed decreased baroreflex sensitivity and increased pressor responses to intracerebroventricular microinjection of either angiotensin II or TNF-α. Furthermore, chronic systemic infusion of angiotensin II resulted in enhanced upregulation of mRNA expression of RAS components, NADPH oxidase and proinflammatory cytokines in the LT and PVN and an augmented hypertensive response in the OHC, OCH and OHH groups when compared to the OCC. The results suggest that maternal HFD blunts baroreflex function and enhances pressor responses to angiotensin II or proinflammaroty cytokines through upregulation of the brain RAS, oxidative stress and inflammation.

continuous carbon fiber reinforced silicon carbide (Cf/SiC) ceramic matrix composites were prepared by precursor infiltration pyrolysis and chemical vapor infiltration (PIP-CVI process), in which the honeycomb sandwich structure preforms were fabricated by the three dimensional braid method. In this paper, the microstructure and the bending strength were observed and analyzed by SEM and three point bending method. The results of the study show that: The Cf/SiC ceramic matrix composites, which were lightweight and high strength, were prepared by that technique. The composite samples have a fiber volume fraction of 20%, a density of 0.38 g/cm3 and a flexural strength of 3.81 MPa. The honeycomb sandwich fiber reinforced ceramic matrix composite with a light weight, corrosion resistance and excellent physical and mechanical properties is a kind of structure and functional ceramic materials, which can realize the structure and the requirement of heat integration.

High thermal conductivity and dense SiC coating were fabricated by chemical vapor deposition (CVD) on surface of different graphite at temperature of 1100°C. The results indicated that the thickness of the coating influences the quality of coating. There was no crack in coating when thickness of the coating is less than 0.3mm. The structure of graphite affected the reaction badly. When the graphite is coarse and porous the reaction is chemical vapor infiltration (CVI) and the interface of coating and substrate isnt obvious. When the graphite is dense and smooth, the coating is covered in surface of graphite, the interface is found between the coating and substrate. Optical microscope and SEM were used to observe the surface and cross-section morphology and microstructure of coatings. It shown coating and substrate had a good combination and the deposited grains mainly showed equiaxed form with the crystallite size of 30 nm at 1100°C.

Fiber reinforced and aluminum phosphate-based composite was studied in this experiment. The composite was prepared through the process of lamination- hot press- sintering, binding material and fillers. The proper mixture ratio of Al2O3:AlPO4:H2O was 10:2.88:2.88.The slurry with this ratio was proper to prepare the composite. It indicated that the mechanical property of composite was excellent which was prepared by the slurry with this ratio. In order to improve the Mechanical property of silica glass fiber / aluminum phosphate composite, Al2O3 powders were graded in the slurry. Mechanical properties of composites were improved evidently.

Highly dense AlN/CNT composite ceramics with 1-10% volume fractions of CNT were fabricated by spark plasma sintered (SPS) at 1400°C-1700°C. The results indicated that origination diameter of AlN had a great effect on microstructure and thermal conductivity. In details, for the system with AlN origination diameter of nanosized, the tubular structure of CNT has not been destructed, but when micro-sized AlN powder was adopted, the structure of CNT showed unstable at high temperature. Even though the degradation with incorporation of CNT into AlN, thermal conductivity of sintered AlN/CNT composites ceramics was evidently improved by adjusting content of additive Y2O3and the sintering process. Both the real part and imaginary part of the composites of Ka-Band (26.540.0 GHz) increase with the increase of CNT content, in which the increase of imaginary part is more than that of real part, resulting in an increase of loss factor. The AlN/ CNT thermal conductivity composites with appropriate CNT content and sintering temperature possess good dielectric dissipation and thermal conductivity.

This paper describes the process of fabricating porous carbon preform by casting the camphene based charcoal slurry. Five kinds of slurry with different solid content varied from 20vol% to 40vol% has been prepared, we have studied the rheological behavior of slurries and the sublimation behavior of casted bodies. Porous carbon preform with negligible linear shrinkage (67vol%) and interconnected pore structure has prepared.

Heart failure (HF) is characterized by cardiac dysfunction along with autonomic unbalance that is associated with increased renin-angiotensin system (RAS) activity and elevated levels of proinflammatory cytokines (PICs). Renal denervation (RD) has been shown to improve cardiac function in HF, but the protective mechanisms remain unclear. The present study tested the hypothesis that RD ameliorates isoproterenol- (ISO-) induced HF through regulation of brain RAS and PICs. Chronic ISO infusion resulted in remarked decrease in blood pressure (BP) and increase in heart rate and cardiac dysfunction, which was accompanied by increased BP variability and decreased baroreflex sensitivity and HR variability. Most of these adverse effects of ISO on cardiac and autonomic function were reversed by RD. Furthermore, ISO upregulated mRNA and protein expressions of several components of the RAS and PICs in the lamina terminalis and hypothalamic paraventricular nucleus, two forebrain nuclei involved in cardiovascular regulations. RD significantly inhibited the upregulation of these genes. Either intracerebroventricular AT1-R antagonist, irbesartan, or TNF-αinhibitor, etanercept, mimicked the beneficial actions of RD in the ISO-induced HF. The results suggest that the RD restores autonomic balance and ameliorates ISO-induced HF and that the downregulated RAS and PICs in the brain contribute to these beneficial effects of RD.

Experiments were carried out to join reaction-bonded silicon carbide (RBSC) ceramic in green body. SiC green bodies were fabricated by gel-casting method. The slurries for joint were prepared by different grain size of SiC. The results indicate the solid loading and the grain size of SiC influence the strength of welding. There is no clear welding interface between the two substrates in an appropriate solid volume loading and grain size. The average bending strength of welding after sintering can reach 300MPa. SEM was used to observe the cross-section morphology and microstructure of binding sites. The test result shows that its microstructure is similar to the RB-SiC ceramic. The mechanical properties of binding sites were tested. The result shows a desirable mechanical property.

A kind of porous SiO2 bulk materials with pore size distributed in nano and micron scales has been fabricated by freeze-casting of SiO2 nano-size powders in TBA (tert-butyl alcohol)/H2O suspensions. The content of TBA in the well mixed TBA/H2O binary co-solvent plays an important role in size and morphology control of the pores in the obtained SiO2 monolithic materials, since the ratio of TBA/H2O determines the competition of crystallization of TBA and ice, therefore, the microstructure of the monolithic SiO2. It was found that the content of TBA in the range from 30 to 40% was suitable for formation of more nano-pores in the SiO2 monolith. The insulation materials freeze-casted from the suspension of SiO2 in 13wt% and TBA in 40wt% has the density of 0.17g/cm3, and the specific surface area of 282m2/g. The pore size has a trimodal size distribution with three mean diameters of 15nm, 100nm and 4μm, respectively.

The porous carbon preforms with fine pore structure has been successfully fabricated by room temperature freezing casting, and the reaction formed SiC with fine mechanical property has prepared successfully by liquid silicon infiltration process. Charcoal powder was used as carbon resource, camphene was used as sublimate vehicle, methyl cellulose was used as pore maker and bonder. The result shows that the homogeneity of the porous carbon preform has been improved largely by adding methyl cellulose ,and the defects of reaction formed silicon carbide has reduced largely also. The density, average flexural strength and Weibull modulus of the best reaction formed silicon carbide prepared in this paper is 2.86 g/cm3, 430.75MPa and 9.29 respectively.

Adhesion is one of the most important mechanical properties of ceramic coatings. Scratch testing is considered as a simple and effective method to evaluate adhesion of ceramic coatings. In this paper, the critical normal forces and scratch morphologies for different coating-substrate systems were studied by scratch testing. It is shown that the critical normal force obtained by acoustic emission (AE) signals decreases from 12 N to 7 N when the applied normal force rate increases from 20 N/min to 100 N/min for CVD SiC on C, and the failure area of this scratched sample increases with increasing maximum normal force; Based on scratch morphologies, spallation or delamination can be observed for hard-brittle coatings on glass or metal, while discontinuous or continuous ductile perforation can be observed for ductile coatings on metal; The critical normal force for hard-brittle coatings can be effectively obtained by AE signals.

In this paper, gel casting process of RBSC was deeply studied. The rheological property of C/SiC slurry was analyzed, high solid loading (67%) slurry with low viscosity was produced. Also the properties of green body and sintered body were studied. Finally, through optimizations of process parameters, a large-sized (650mm), complex-shaped (with thin ribs about 2.5mm) was fabricated through gel casting process with no cracks and deformation. It was showed that gel casting process is suitable for producing large-sized, complex-shaped RBSC components.

In this paper, the green RBSC was prepared by gel casting process. The influences of the monomer content (MBAM and AM) and monomer ratio (MBAM to AM) on the flexural strength were investigated. The results indicated the flexural strength of green body was up to 8MPa and the micro- structures were homogeneous. The green RBSC bodies were machined by CNC grinding machine with diamond-coated grinding tools. Machining tests showed the green component could be machined without appended defects. It was found that green machining as a ‘top-down’ approach was a potential alternative for the rapid fabrication of complex-shaped ceramics, especially for some one-of-a-kind products.

The Cf/SiC made from carbon fiber preforms infiltrated by phenol resin, pure carbon slurry and aqueous C/SiC slurry showed different binding strength between carbon fiber and SiC matrix, thus influenced the fracture behavior of the composite. The fracture toughness of the Cf/SiC composites with the value of 9.82MPa•m1/2,improved remarkably compared with reaction- bonded silicon carbide (RBSC). But the flexural strength was less than 100 MPa, because of the existence of considerable amount of pores in C/SiC composites.

A SiC coating was chemical vapour deposited (CVD) on a Cf/SiC composite with the ratio of H2 and methyltrichlorosilane (MTS) changed gradually from 6:1 to 12:1 during the CVD processing. Energy-dispersive spectrometry (EDS) of the coating showed that the content of C decreased while Si increased continuously from the interface between coating and Cf/SiC substrate to the outside surface of coating. The obtained compositionally graded structure effectively reduced the generation of microcracks by releasing the mismatch of CTE of the coating and the composite.

The effects of deposition temperature on the growth characteristics of CVD SiC coatings were investigated. CVD SiC coatings were made by pyrolysis of methyltrichlorosilane (MTS) in hydrogen at a low pressure of 5kPa. The ratio of MTS to hydrogen was 1/12. The deposition temperatures were varied from 1373K to 1503K. Optical microscope and SEM were used to observe the surface morphology and microstructure of the coatings. XRD was used for characterization of the phase composition. Results indicated that the deposition rate and the surface roughness varied with deposition temperature. At 1373K, the deposited grains were mainly equiaxed with the crystallite size of 22 nm. However, when the deposition temperature was 1503K, the SiC grains were mainly showed faceted columnar structure with the crystallite size of 32 nm. Grain size increased with the increase of deposition temperature.