Search

Ordered nanoporous carbons (ONCs) were prepared from sucrose as precursor and SBA-15 or NaY zeolite as template by impregnation method. The sucrose and its pre-carbonized template composite were analyzed by thermal gravimetric analysis. The morphology and microstructure of resultant ONCs were measured by Transmission Electron Microscope, X-ray diffraction and nitrogen adsorption specific surface area techniques, respectively. The effects of template and carbonization temperature on the microstructure of ONCs were investigated. It was shown that SBA-15 is an ideal template for preparing ONCs, from which ONCs with the ordered porous diameter about 8 nm was obtained. The ONCs obtained from NaY are of poor regularity owing to its partial duplication of template NaY.

Considering utilization of the original chromium-bronze material, two processing techniques including hydraulic expansion and high temperature vacuum welding were proposed for the optimization of heat-sink structure in EAST. The heat transfer performance of heat-sink with or without cooling tube was calculated and different types of connection between tube and heat-sink were compared by conducting a special test. It is shown from numerical analysis that the diameter of heat-sink channel can be reduced from 12 mm to 10 mm. Compared with the original sample, the thermal contact resistance between tube and heat-sink for welding sample can reduce the heat transfer performance by 10%, while by 20% for the hydraulic expansion sample. However, the welding technique is more complicated and expensive than hydraulic expansion technique. Both the processing technique and the heat transfer performance of heat-sink prototype should be further considered for the optimization of heat-sink structure in EAST.

EAST plasma facing components (PFCs) have the function of protecting the vacuum vessel, heating systems and diagnostic components from the plasma particles and heat loads, and also additional to this particles and heat loads handling. The PFCs are designed up–down symmetry to accommodate with both double null and single null plasma configuration. All PFCs use graphite tile for plasma facing surfaces affixed to copper alloy heat sink considering economical factor. Based on this structural design, detailed structural and thermal analysis had been carried out. A special deep hole drilling technology was developed to drill cooling channels directly on heat sink for high efficient heat removal. A dry lubricate material is used between stainless steel support and heat sink for the purpose of absorption of thermal expansion. And analysis results show that the present PFCs need to be improved for the next stage of steady state operation. The PFCs are installed in the vacuum vessel together with in-vessel coils, cryopump and diagnostic components. The design, analysis, manufacture and assembly have been finished. As indicated, all the in-vessel components were fabricated and assembled successfully and meet the design requirement for the plasma operation.

This paper mainly contributes to the estimation of 2-D current-density distribution in a moving arc root. For this purpose, the multiple-split-cathode-with-different-slit-angle method is used to perform measurements of the linear current distribution of the arc root in seven different directions. On the basis of the measurement results, a large system of linear algebraic equations is treated with the algebraic-reconstruction-technique algorithm to obtain the 2-D current density. The calculation results indicate that the transverse profile of current density in a moving arc root can be characterized by a high-current core with two low-current hysteretic wings and that the maximum current density tends to the fore part of it.

A new polymeric precursor, poly(phthalazinone ether sulfone) (PPES), was used as precursor to prepare carbon membranes via stabilization and pyrolysis. The thermal stability of PPES was determined ...

This paper focuses on the numerical research of the influence of polymer (polyoxymethylene) on the arc behavior during arc-motion process. The mathematical model of 3-D air-arc plasma considering the ablation of sidewalls is built based on magnetic hydrodynamics. The mass-fraction equation is introduced to the model on the basis of traditional mass, momentum, and energy-balance equations. The influence of wall ablation on the thermodynamic and transport properties of air-polymer mixtures is considered in this paper. The distributions of temperature field, pressure field, and mass fraction in the arc chamber are calculated. The simulation results indicate that the vapor concentration behind the arc column is higher than that in front of the arc column because of the existence of ldquovortexrdquo in the arc chamber. The use of polymers could accelerate arc movement and reduce the probability of occurrence of back-striking. Using polymers can also increase arc voltage, which can be explained by the change of electrical conductivity for air-polymer vapor mixtures.

This paper focuses on the numerical and experimental investigations of the influence of two polymers (PA6 and POM) on the arc behavior during arc motion process. The mathematical model of 3-dimentional air arc plasma considering the ablation of lateral walls is built based on magnetic hydro-dynamics (MHD). By adopting the commercial computational fluid dynamics (CFD) package based on control-volume method, the above MHD model is solved and the distribution of temperature field, concentration field, flow field and electrical potential field in the arc chamber are calculated. The simulation results indicate that the vapor concentration behind the arc column is higher than that in front of the arc column because of the existence of "double vortices" in the arc chamber. The use of polymers causes the maximal arc voltage increase 16.2% with POM and 18.9% with PA6 in this case and causes the average arc velocity increase 15.8% with POM and 21.1% with PA6 in this case. The experiments are also carried out to study the influence of polymers on arc voltage and arc root position in the arc chamber during arc motion. The experimental results prove the validity of the numerical investigation.

Addiction to nicotine may result in molecular adaptations in the neurocircuitry of specific brain structures via changes in the cyclic AMP-responsive element binding protein (CREB)-dependent gene transcription program. We therefore investigated the effects of chronic nicotine exposure and its withdrawal on CREB and phosphorylated CREB (p-CREB) protein levels in the rat brain. We report here that chronic nicotine exposure (1-h withdrawal) had no effect on the expression of CREB and p-CREB in the rat cortex and amygdala. On the other hand, decreases in the expression of CREB protein and phosphorylation of CREB occur in the cingulate gyrus, and in the parietal and the piriform but not in the frontal cortex during nicotine withdrawal (18 h) after nicotine exposure. It was also observed that CREB and p-CREB protein levels were significantly decreased in the medial and basolateral, but not in the central amygdala during nicotine withdrawal (18 h) after chronic nicotine exposure. Furthermore, it was found that nicotine withdrawal (18 h) after chronic nicotine exposure leads to decreased CRE-DNA binding without modulating cAMP-dependent protein kinase A activity in the cortex and the amygdala of rats. In addition, chronic nicotine treatment produced anxiolytic effects whereas nicotine withdrawal (18 h) produced anxiety in rats as measured by the elevated plus-maze test. These results provide the first evidence that decreased CREB activity and/or expression in specific cortical and amygdaloid brain structures may be involved in the underlying molecular mechanisms of nicotine dependence.

The present study was performed to investigate the effects of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) antisense oligodeoxynucleotides (ODNs) on the assembly of the CaMKII·GluR6·PSD-95 signaling module, GluR6 serine phosphorylation and c-Jun N-terminal kinase 3 (JNK3) activation. A further aim was to determine the neuroprotective mechanism of CaMKII antisense ODNs against ischemia–reperfusion (I/R)-induced neuronal death in the rat hippocampus. CaMKII antisense ODNs were intracerebroventricularly infused to inhibit CaMKII expression once daily for 3 days prior to the induction of ischemia. Transient cerebral ischemia (15 min) and reperfusion were induced by four-vessel occlusion in Sprague–Dawley rats as an animal model for transient cerebral I/R. The expression of related proteins was examined by immunoprecipitation and immunoblotting. Neuronal death in the rat hippocampus was detected by histology and histochemistry. The results indicate that CaMKII antisense ODNs inhibit several of the processes that are normally induced by cerebral I/R, including CaMKII expression, increased CaMKII·GluR6·PSD-95 signaling module assembly, GluR6 serine phosphorylation and JNK3 activation. Alternatively, CaMKII antisense ODNs also exhibit a significant neuroprotective role against cerebral I/R-induced cell death. These results provide the first evidence that CaMKII antisense ODNs can exert neuroprotective effects on cerebral I/R-induced cell death. The possible molecular mechanisms underlying this effect include 1) an inhibition of CaMKII expression and subsequent suppression of the assembly of the CaMKII·GluR6·PSD-95 signaling module, 2) GluR6 serine phosphorylation, and 3) reduced JNK3 activation.

The common inhalation anesthetic isoflurane has been shown to induce apoptosis, which then leads to accumulation of beta-amyloid protein, the hallmark feature of Alzheimer disease neuropathogenesis. The underlying molecular mechanism of the isoflurane-induced apoptosis is largely unknown. We, therefore, set out to assess whether isoflurane can induce apoptosis by regulating Bcl-2 family proteins, enhancing reactive oxygen species (ROS) accumulation, and activating the mitochondrial pathway of apoptosis. We performed these studies in cultured cells, primary neurons, and mice. Here we show for the first time that treatment with 2% isoflurane for 6 h can increase pro-apoptotic factor Bax levels, decrease anti-apoptotic factor Bcl-2 levels, increase ROS accumulation, facilitate cytochrome c release from the mitochondria to the cytosol, induce activation of caspase-9 and caspase-3, and finally cause apoptosis as compared with the control condition. We have further found that isoflurane can increase the mRNA levels of Bax and reduce the mRNA levels of Bcl-2. The isoflurane-induced ROS accumulation can be attenuated by the intracellular calcium chelator BAPTA. Finally, the anesthetic desflurane does not induce activation of mitochondrial pathway of apoptosis. These results suggest that isoflurane may induce apoptosis through Bcl-2 family proteins- and ROS-associated mitochondrial pathway of apoptosis. These findings, which have identified at least partially the molecular mechanism by which isoflurane induces apoptosis, will promote more studies aimed at studying the potential neurotoxic effects of anesthetics.

EAST plasma facing components (PFCs) have the function of protecting the vacuum vessel, heating systems and diagnostic components from the plasma particles and heat loads, and also additional to this particles and heat loads handling. They are installed in the vacuum vessel together with in-vessel coils, cryopump and diagnostic components. The design, fabrication and assembly have been finished. The PFCs are designed up-down symmetry to accommodate with both double null and single null plasma configuration. All PFCs use graphite tile for plasma facing surfaces affixed to copper alloy heat sink. A special deep hole drilling technology was developed to drill cooling channels directly on heat sink for high efficient heat removal. All Heat sink are installed onto the base alignment rails through stainless steel supports. As the benchmark of assembly for PFCs, the base rails are installed and measured precise based on a new alignment method integrating the optical instruments and a mechanical template. And so is a mechanical check template for checking the surface of first wall. As indicated, all the first wall components were fabricated and assembled successfully and meet the design requirement for the plasma operation.

The paper, based on the fuzzy question of the multi-objective ore blending, firstly, gives the solving analysis of its characteristics and complication. Then, the two-step fuzzy optimization algorithm is designed based on the sequence of linguistic satisfaction. The algorithm places weight on the improvement of optimality and importance model. Ultimately, a simulation study is conducted through a mine ore blending example. The effectiveness, flexibility, and sensitivity of algorithm are verified. Which overcome the solving difficulty in applying the multi-objective planning to the ore blending, and a practical, great universal method or means for the ore blending is explored.

This study aims at the reconstruction of anode two- dimensional current density distribution in a moving arc root using algebraic reconstruction technique(ART). The principle of the multi-angle slit-cavity electrode is proposed to obtain the linear current distribution of arc root in diverse directions on the basis of work made by Drouet and his cooperators. The iterative reconstructive algorithm associated with ART is introduced. The measured results of linear current distribution in seven directions are processed with the ART algorithm, and two-dimensional current density in arc root is obtained. Keywords-arc root; anode current density distribution; ART.

The immediate early gene, activity-regulated cytoskeleton-associated protein (Arc), has been implicated in synaptic plasticity. However, the role of Arc in alcoholism is unknown. Here, we report that the anxiolytic effects of acute ethanol were associated with increased brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (trkB) expression, increased phosphorylation of extracellular signal-regulated kinases 1/2 (Erk1/2), Elk-1, and cAMP responsive element-binding protein (CREB), increased Arc expression, and increased dendritic spine density (DSD) in both the central amygdala (CeA) and medial amygdala (MeA) but not in the basolateral amygdala (BLA) of rats. Conversely, the anxiogenic effects of withdrawal after long-term ethanol exposure were associated with decreased BDNF and trkB expression, decreased phosphorylation of Erk1/2, Elk-1, and CREB, decreased Arc expression, and decreased DSD in both the CeA and MeA but not in the BLA of rats. We also showed that BDNF infusion into the CeA normalized phosphorylation of Erk1/2, Elk-1, and CREB, and normalized Arc expression, thereby protecting against the onset of ethanol withdrawal-related anxiety. We further demonstrated that arresting Arc expression in the CeA decreased DSD, thereby increasing anxiety-like and alcohol-drinking behaviors in control rats. These results revealed that BDNF–Arc signaling and the associated DSD in the CeA, and possibly in the MeA, may be involved in the molecular processes of alcohol dependence and comorbidity of anxiety and alcohol-drinking behaviors.

We investigated the role of cAMP-responsive element–binding protein (CREB) in genetic predisposition to anxiety and alcohol-drinking behaviors using alcohol-preferring (P) and -nonpreferring (NP) rats. The levels of CREB, phosphorylated CREB, and neuropeptide Y (NPY) were innately lower in the central amygdala (CeA) and medial amygdala (MeA), but not in the basolateral amygdala (BLA), of P rats compared with NP rats. P rats displayed higher baseline anxiety-like behaviors and consumed higher amounts of alcohol compared with NP rats. Ethanol injection or voluntary intake reduced the higher anxiety levels in P rats. Ethanol also increased CREB function in the CeA and MeA, but not in the BLA, of P rats. Infusion of the PKA activator Sp-cAMP or NPY into the CeA decreased the alcohol intake and anxiety-like behaviors of P rats. PKA activator infusion also increased CREB function in the CeA of P rats. On the other hand, ethanol injection or voluntary intake did not produce any changes either in anxiety levels or on CREB function in the amygdaloid structures of NP rats. Interestingly, infusion of the PKA inhibitor Rp-cAMP into the CeA provoked anxiety-like behaviors and increased alcohol intake in NP rats. PKA inhibitor decreased CREB function in the CeA of NP rats. These novel results provide the first evidence to our knowledge that decreased CREB function in the CeA may be operative in maintaining the high anxiety and excessive alcohol-drinking behaviors of P rats.

The cAMP response element-binding protein (CREB) gene transcription factor has been shown to play a role in the synaptic plasticity associated with drug addictive behaviors; however, the causal role of the CREB gene in alcohol-drinking behaviors is unknown. The present investigation evaluated alcohol-drinking behaviors in mice that are haplodeficient in CREB as a result of targeted CREB (α and Δ) gene disruption. It was found that CREB-haplodeficient (+/-) mice have higher preference for ethanol but not for sucrose solution than wild-type (+/+) littermates. The functional aspects of the CREB gene transcription factor were also investigated by measuring the protein levels of phosphorylated CREB (p-CREB) and the expression of cAMP-inducible genes such as neuropeptide Y (NPY) and brain-derived neurotrophic factor (BDNF). Deletion of the CREB (α and Δ) gene significantly decreases total CREB, p-CREB levels and the expression of NPY and BDNF in the brain structures of CREB-deficient (+/-) mice. It was also found that CREB-deficient (+/-) mice displayed more anxiety-like behaviors and that acute ethanol exposure produced anxiolytic effects and significantly increased protein levels of p-CREB and NPY in the central and medial but not in the basolateral amygdala of wild-type mice, but these effects are attenuated in CREB-deficient mice compared with wild-type mice. These results provide the first direct evidence that a haplodeficiency of the CREB gene is associated with increased alcohol-drinking behaviors. Furthermore, alcohol drinking and anxiety-like behaviors in CREB-haplodeficient mice may possibly be related to decreased expression of NPY and BDNF in the brains of these mice.

Based on theory and method of the near-field optics, optical resolution of near-field scanning optical microscopy (NSOM) is beyond the classical optical diffraction limit and down to tens of nanometer or even less. In this paper, a collection mode NSOM is built to detect and analyze local near-field distribution. The output optical field of a standard 1μm×1μm scale 2D grating has been detected. This NSOM system can also be used to study local near-field distribution of the focused spot of solid immerging lens (SIL) and the result can be directly used to evaluate SIL and compared with the calculation of its theoretical model and as a result, to improve the theoretical model.

Nanometric light source is one ofthe most important elements in near-field optical system. In this paper the nearfield distribution of nano-aperture lasers (NAL) with square and asymmetrical C aperture are characterized by the method of 3D finite-difference time-domain (FDTD). The simulation results theoretically reveal that the output power peak from the asymmetrical NAL is three or four orders of magnitude higher than that from the normal square or round aperture with the comparable light spot size in the near-field region and power throughput is more than unity. The maximum ofthe field enhancement occurs at the C aperture size corresponding to one third ofwavelength. The effects of configuration, aperture dimension, electric field component, polarization and separation in local near field close to the aperture have been investigated theoretically and numerically. The mechanism of electromagnetic field enhancement is also discussed. The asymmetrical NAL with higher throughput may expand the range of applications possible in near-field optics.

The effects of acute and chronic nicotine treatment on activator protein-1 (AP-1) gene transcription factor binding activity in the rat cortex were investigated. AP-1 DNA binding activity was determined by the electrophoretic gel mobility shift assay. It was observed that 1 h after acute nicotine treatment (single injection) AP-1 DNA binding activity was significantly increased in the rat cortex. On the other hand, AP-1 DNA binding activity in the rat cortex was not altered at 1 and 8 h of nicotine withdrawal after repeated nicotine treatment (10 days). However, at 18 and 24 h of nicotine withdrawal after 10 days of nicotine treatment, AP-1 DNA binding activity was significantly decreased in the rat cortex. Thus, these findings suggest that desensitization of cortical AP-1 DNA binding activity may be involved in the neuroadaptational mechanisms to nicotine dependence.

This paper focuses on the numerical research of the influence of electrode erosion on the arc behavior during opening process of low-voltage circuit breakers. The mathematical model of three-dimensional air arc plasma considering electrode erosion is built based on magnetic hydrodynamics. The mass fraction equation of copper vapor is introduced to the model on the basis of traditional mass, momentum, and energy balance equations. The influence of copper vapor on the thermodynamic and transport properties of the gas mixture is considered in this paper. The distributions of temperature field, gas flow field, and mass fraction of copper vapor in the arc chamber are simulated. The arc root displacements and arc voltage, which takes account of the influence of electrode erosion, are calculated. The simulation results indicate that the immobility time of both moving contact and stationary contact is much longer considering electrodes erosion. The calculated voltage of the arc column during arc motion considerin...

We summarize some design tips and design procedures of nanoapertures with strong field enhancement, based on the theoretical calculations and analyses of near-field distributions of unconventional C apertures and bow-tie apertures by a finite-difference time-domain method. A novel L-shaped aperture is proposed and further validates the proposed design rule. As a result, a 15×15-nm full width half maximum spot forms in the light exit plane of the L aperture. Its intensity maximum enhancement reaches a factor of about 568 and the power throughput is bigger than unity. The mechanisms of electromagnetic field enhancement are preliminarily analyzed. This unconventional nanoaperture is likely to be directly used as an exit aperture of very small aperture lasers, or as an unattached shield, to produce a subwavelength light source with high transmission.