CS Process Research Articles

Microstructures and electrical properties of lead-based PBZNZT and lead-free BNKT piezoelectric ceramics using microwave sintering

This paper is a comparative study involving sintering conditions (different sintering temperatures and time), process (conventional and microwave sintering), microstructures, and electrical measurements to investigate the mechanism of microwave absorption, and the difference in the microstructural characteristics and electrical properties of lead-based and lead-free ceramics. The lead-based piezoelectric ceramics are x(0.94PbZn 1/3Nb 2/3O 3 + 0.06BaTiO 3) + (1 − x)PbZr y Ti 1− y O 3 where x = 0.5, y = 0.52 (abbreviated as PBZNZT) and the lead-free ceramics are (Bi 0.5(Na 1− x K x ) 0.5)TiO 3 where x = 0.18 (abbreviated as BNKT), all sintered by microwave heating. Experimental results indicate that PBZNZT and BNKT specimens have different microwave absorption efficiencies. Compared with BNKT samples, PBZNZT samples absorb microwave radiation more efficiently in MWS process. This might be attributed to the contribution of the dielectric constant and dipole loss which might dominate the absorption of microwave energy for ferroelectric and piezoelectric materials. HRTEM and energy dispersive spectroscopic investigations show that the grain boundaries of MWS samples exhibit less PbO and ZnO segregation than those of CS samples form PBZNZT specimens. On the other hand, BNKT specimens exhibit no compositional segregation at the grain boundaries after the CS and MWS processes. In addition, the MWS process can achieve a more uniform composition and crystallization in PBZNZT and BNKT ceramics, thus improving the electrical properties.

STRUCTURAL, ELECTRICAL AND MAGNETIC CHARACTERIZATION OF Ni–Cu–Zn SPINEL FERRITES

Ni – Cu – Zn ferrite materials have been extensively used in multilayer chip inductors because of their remarkable properties at higher frequencies. In the present work, single phase Ni 0.35 Cu 0.05 Zn 0.60 Fe 1.98 O 4-δ ferrite, has been prepared by microwave sintered (MS) method. In comparison with the conventional sintering method (CS), the sintering temperature and time for this MS method were significantly reduced to 30 min and 950°C from 5 h and 1250°C for the CS process. The frequency dependence of the dielectric properties such as dielectric constant (ε'), dielectric loss ( tan δ) were studied. The temperature dependence of magnetic initial permeability (μi) was studied. The saturation magnetization was also studied as a function of magnetic field. These microwave sintered ferrites results were compared with the properties of ferrites prepared by conventional sintering method in normal heating. Microwave sintering improves structural as well as electromagnetic parameters measured and thus makes the ferrite more suitable in microwave applications and electromagnetic devices.

Immobilization of Cs and Sr to HZr2(PO4)3 using an autoclave

The proton-type crystalline zirconium phosphate, HZr2(PO4)3, was prepared by a thermal decomposition of NH4Zr2(PO4)3 at about 450°C, where NH4Zr2(PO4)3 was obtained in advance by a hydrothermal synthesis using a mixed solution of ZrOCl2, H3PO4 and H2C2O4. Cs or Sr ion was immobilized to HZr2(PO4)3 by mixing HZr2(PO4)3 with an aqueous solution of CsNO3 or Sr(NO3)2 under the molar ratio CsNO3/HZr2(PO4)3=1.0 or Sr(NO3)2/HZr2(PO4)3=0.5. The mixtures were treated thermally in an autoclave at different temperatures from 200 to 275°C and Arrhenius equation was applied to the Cs and Sr immobilization process to HZr2(PO4)3. The activation energy for the immobilization process of Cs or Sr was estimated as 179kJmol−1 and 186kJmol−1, respectively.

Participation of primary motor cortex area 4a in complex sensory processing: 3.0-T fMRI study

The precise movement of human fingers requires continuous and reciprocal interaction between motor and sensory systems. Similar to other primates, there is double representation of the digits and wrists within the human primary motor cortex (M1), which are generally referred to as area 4 anterior (M1-4a) and area 4 posterior (M1-4p). In this high-field (3.0 T) functional magnetic resonance imaging (fMRI) study, we hypothesized that M1-4p is more important for initiation of motion, whereas M1-4a is important for execution of a given motion involving more complex sensoriomotor interaction. We investigated M1-4a and M1-4p activation associated with two representative motor tasks, namely, finger tapping (voluntary motion, VM) and passive finger movement accomplished by continuous pressure (passive motor, PM), and two representative sensory stimulations, namely, simple stimulation of flutter vibration (simple sensory, SS), and complex stimulation by a row of pins moving either vertically or horizontally (complex sensory, CS). Both M1-4a and M1-4p were activated in both motor tasks, VM and PM. M1-4p was not activated by either of the two sensory tasks, whereas M1-4a was activated by CS but not by SS. Analysis of the center of gravities (COG) of the activated areas showed that VM and PM moved COG towards M1-4p and 3a. SS moved COG towards somatosensory cortex Brodmann areas 1, 2, and 3b, whereas CS towards M1-4a. The result clearly showed that M1-4a represents the area of secondary motor execution, which actively participates in CS processing.

Diffusion of cesium and selenium in crushed mudrock

In this study, the diffusion behavior of cesium and selenium with 10−4M concentration in mudrock was studied by trough-diffusion tests and summarized in order to provide confidence on long-term performance assessment of nuclear waste repositories. The diffusion process of Cs and Se reached equilibrium after 60 and 500 days, respectively. Besides, it also displays that the distribution coefficients (Kd) of Se in through-diffusion tests is higher than that of Cs in agreement with that obtained from the batch method. The Kd value (15.14±1.99 mL/g) of Cs by diffusion techniques is equivalent to that of batch method (15.10±0.40 mL/g) because sorption of Cs was assumed to fast sorption step. However, the Kd value of Se (137.58±12.20 mL/g) derived from the diffusion technique is higher than that from batch tests (76.72±2.96) and showed an obvious variation with Kd of Cs. The difference of Kd between diffusion and batch methods resulted from the fact that 14 days were not long enough to reach equilibrium or stable state in the batch method.

Study on zeolite enhanced contact–adsorption regeneration–stabilization process for nitrogen removal

Utilizing preferential ion exchange of zeolite to ammonium, the conventional contact stabilization activated sludge process (CS) can be upgraded to a new type nitrogen removal process, zeolite enhanced contact–adsorption regeneration–stabilization process (ZCS). For municipal wastewater, the effluent ammonium concentration of the ZCS process was around 6.83 mg/L, indicating that ammonium removal efficiency was enhanced over 27% when the influent ammonium concentration was between 24.7 and 50.5 mg/L in the same hydraulic retention time (HRT) and sludge retention time (SRT) conditions as those of the CS process. The results of PCR-DGGE technology showed that the microbial diversity, uniformity and abundance of the ZCS process were all higher than that of the CS process. In addition, anoxic/oxic (A/O) process with the volumetric ratio of oxic tank to anoxic tank being 2:1 was preferred for the regeneration process. The pilot scale ZCS process with the capacity to treat up to 72 m 3/d of municipal wastewater was also monitored. The test results revealed that ammonium saturated zeolite could be biologically regenerated effectively and in time. The daily zeolite powder addition was limited to the amount that made up the loss due to the sludge excluding. Furthermore, the orthogonal experiments results showed that the most significant effects on nitrogen and ammonium removal were zeolite powder dose and external recycle ratio, respectively.

The toxic function of cesium 5-sulfosalicylate based on the investigation of its trans-erythrocytes membrane behaviors and morphological properties

In order to evaluate the cesium-induced toxic functional changes in organisms, transmembrane activities of cesium 5-sulfosalicylate (Cs(H 2Ssal)) into human erythrocyte in vitro is presented in this paper, including kinetic characteristic of transport process and pathways involved in it. The uptake amount of Cs(H 2Ssal) by erythrocyte was determined both by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) and spectrofluorimetry. The pathways of Cs(H 2Ssal) transporting into erythrocyte are proposed according to inhibition investigation. The influence of Cs(H 2Ssal) on morphological properties of erythrocytes was examined using Scanning Electron Microscopy (SEM) to determined the endurable concentration extent of erythrocytes to Cs(H 2Ssal). Results show that transmembrane of Cs(H 2Ssal) has characteristic of first-order kinetic process during the first 2 h, and four pathways were involved in its transporting activities: Ca 2+ channel, Na +-K + pump, Na +-Cs + countertransport, and anion Cl −/CsCO 3 − exchange. The transmembrane process of Cs(H 2Ssal) can both prevent the uptake of K + and induces abnormal accumulation of extracellular K + as well as occupy some K +-binding sites in protein, causing some tissues losing their activities and functions. Only high concentrations of Cs(H 2Ssal) could change morphological properties of erythrocytes greatly and cause hemolysis eventually.

Serotonin and dopamine in the parabrachial nucleus of rats during conditioned taste aversion learning

A microdialysis technique was used to monitor changes in serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) and dopamine (DA) in the extracellular space of the parabrachial nucleus (PBN) of rats to estimate the contribution of these neurotransmitter systems to the acquisition of conditioned taste aversion (CTA). A significant (280%) enhancement of 5-HT was found immediately after saccharin drinking (CS). I.p. injection of unconditioned stimulus LiCl alone (after water drinking) also increased level of 5-HT (200%). However, when saccharin intake was followed by injection of LiCl (CS–US pairing), no change in 5-HT was observed. 5-HIAA and DA were unaffected by any of the above treatments. Thus in spite of elevation of 5-HT in PBN following saccharin consumption alone (CS) or LiCl administration alone (US) no changes in 5-HT occurred after pairing of both stimuli (CS–US). Our work demonstrates that participation of 5-HT in acquisition of CTA appears to be unlikely, and also DA appears not to be engaged in this acquisition at all. At the level of the PBN 5-HT participates mainly in CS and/or US stimuli processing, where this phenomenon has close relationship to other important physiological mechanisms, involved in behavioral control. Such as anxiety, alimentation intake.

Carbon-supported ruthenium catalysts for NH 3 synthesis doped with caesium nitrate: Activation process, working state of Cs–Ru/C

The process of an active Cs–Ru/carbon catalyst formation (reduction) was studied in detail, using graphitised carbons as supports for ruthenium and caesium nitrate as a promoter precursor. In situ XRD and TPR-MS techniques were applied to monitor the changes in the specimens when heating in H 2 and H 2 + Ar mixtures, respectively. The postactivation state of the catalysts (i.e., the state corresponding to ammonia synthesis conditions) was characterised chemically via interaction of the reduced samples with water vapour at 50 °C (H 2 evolution) and also via interaction with oxygen at 0 °C. These experiments were supplemented with those of ammonia synthesis. Ruthenium was shown to facilitate the decomposition of caesium nitrate; whereas the Ru-free CsNO 3/C reference materials are stable in a flowing H 2 + Ar mixture up to about 400 °C, the CsNO 3 decomposition starts at 100–120 °C for the CsNO 3–Ru/C catalysts (XRD, TPR-MS) and proceeds via a CsOH⋅H 2O-intermediate product that turns into an amorphous species at elevated temperatures, as indicated by XRD. Characterisation studies of the postactivation catalysts showed that caesium is partially reduced during operations and reacts with oxygen (O 2 consumption) and water vapour (H 2 evolution). The degree of promoter reduction resulting from H 2 liberation varies from 0.25 to 0.45, depending on the Cs loading, Ru loading, and kind of carbon. Combining the O 2 consumption and H 2 evolution data suggests that a substoichiometric oxide (Cs x O y ; x / y = 2.7 – 3.6 ) exists on the catalyst surface rather than Cs 0 + CsOH. High activities (TOFs) of the optimally promoted Cs–Ru/C systems in ammonia synthesis (63 bar, 370 and 400 °C) were ascribed to the strong promotional effect of partly reduced caesium (Cs x O y ) covering the Ru surface. A peculiar S-like shape of the TOF trace versus Cs loading is suggested to be a consequence of the promoter distribution between the carbon surface and surface of ruthenium. Clearly, the trend in TOF reflects that in Ru coverage by the Cs x O y groups, the latter being controlled by the heats of Cs x O y adsorption on ruthenium and on carbon, respectively.

Systemic and Intra-Amygdala Administration of Glucocorticoid Agonist and Antagonist Modulate Extinction of Conditioned Fear

We examined the effect of glucocorticoid agonists on the extinction of conditioned fear in rats by using fear-potentiated startle. Systemic injection of glucocorticoid receptor agonists dexamethasone (DEX) (0.1, 0.5, and 1.0 mg/kg) and intra-amygdala infusion of RU28362 (0.5, 1.0, and 3.0 ng/side) prior to extinction training facilitated extinction of conditioned fear in a dose-dependent manner. Extinction of conditioned fear and circulating corticosterone levels were attenuated by administration of corticosteroid synthesis inhibitor metyrapone (25 mg/kg s.c.) 90 min before extinction training. The facilitation effect of DEX was dependent on repeated presentation of the conditioned stimulus rather than exposure to the experimental context, indicating this effect did not result from impaired expression of conditioned fear or accelerated forgetting. Intra-amygdaloid administration of the glucocorticoid receptor antagonist mifepristone (0.1, 0.2, and 0.5 ng/side, bilaterally) blocked extinction of conditioned fear and the facilitation effect of DEX in a dose-dependent manner. Mifepristone (2 ng/side) did not affect extinction but blocked the facilitating effect of DEX. Systemic administration of DEX after extinction training also facilitated extinction, suggesting that DEX may influence the memory consodilation phase of extinction. The Dose of dexamethsone or metyrapone used here did not influence fear-potentiated startle when administered before testing. Thus, it is unlikely that these drugs influenced extinction by increasing or disrupting CS processing. All results suggested that amygdaloid glucocorticoid receptors were involved in the extinction of conditioned fear.

Recovery of the rabbit's conditioned nictitating membrane response without direct reinforcement after extinction.

Three experiments demonstrated that, following the extinction of an established conditioned stimulus (CSA--e.g., tone), the pairing of a novel, cross-modal stimulus (CSB--e.g., light) with the unconditioned stimulus (US) results in strong recovery of responding to the extinguished CSA. Experiment 1 demonstrated that the recovery of responding to CSA is not the result of US reinstatement but is attributable to pairings of CSB with the US. Experiment 2 demonstrated that the recovery of responding is specific to CSA and is not the result of cross-modal generalization. Experiment 3 revealed that a large number of CSB-US pairings in Stage 1 significantly reduced the amount of recovery to CSA during subsequent CSB-US trials. Experiment 3 also provided unexpected evidence of cross-modal secondary extinction. The extinction and subsequent recovery of responding seen in the present experiments is discussed with respect to possible contributions from contextual associations, CS processing, US processing, conditioned response expression, and layered excitatory associations.

Latent inhibition disruption by MK-801 in a conditioned taste-aversion paradigm

N-Methyl- d-aspartate (NMDA) receptors appear to be involved in CS processing and memory consolidation. The present paper analyzed the effect of the non-competitive NMDA receptor antagonist Dizocilpine maleate (MK-801) on Latent Inhibition (LI)—retarded learning of a CS–US association after to-be-CS preexposures at time of testing, using Wistar rats as experimental subjects. If NMDA receptors are involved in CS processing, MK-801 administration should affect LI. In fact, previous experiments revealed that a 2.0 mg/kg MK-801 dose, administered 20 h before preexposure and conditioning, abolished LI in a conditioned taste-aversion paradigm ( Turgeon, Auerbach, Duncan-Smith, George, & Graves, 2000). In the present paper, MK-801 (0.2 mg/kg) was either injected after preexposure, after conditioning, or after both preexposure and conditioning stages. LI was abolished when MK-801 was injected after preexposure, but not when it was injected after conditioning. These results support the role of NMDA receptors in CS processing and memory consolidation.

Sequential three-body Coulomb explosion of CS 2 in intense laser fields appearing in momentum correlation map

The three-body Coulomb explosion process of CS 2 in intense laser fields ( 60 fs , 0.36×10 15 W/ cm 2 ), CS 2 3+→S ++C ++S +, is studied by the triple coincidence momentum imaging of the atomic fragment ions. The set of the observed momentum vectors of the fragment ions determined for respective explosion events exhibits a clear trajectory originating from the rotational motion of an intermediate CS 2+ ion, formed in a sequential explosion process of CS 2 3+ prior to the complete three-body fragmentation. The contribution of the sequential pathway to the overall three-body explosion process is estimated to be 17(1)%.

Nonlinear electrical properties of ZnO varistors fast-fired by using millimeter-wave sintering process

Fast firing of Bi2O3-based ZnO varistor materials, which includes zero minutes soaking at 1100°C with 120°C/min heating and 145°C/min cooling rate, was made possible using millimeter-wave sintering (mS) technique. The overall sintering time of the process is less than 18 minutes, and the varistor characteristics obtained are α = 38, JL = 5.55 × 10−6 A/cm2 and Vbk = 600 V/mm, whereas the intrinsic parameters of the materials are φb = 2.84 eV, Nd = 1.85 × 1024 m−3 and Ns = 7.02 × 1011 cm−2. By contrast, conventional sintering (cS) process needs higher sintering temperature (1200°C), longer soaking time (60 min) and slower ramping rate (30°C/min) to obtain ZnO materials with the same marvelous nonlinear properties as those prepared by mS-process. Moreover, millimeter-wave sintering (24 GHz, mS) process enhances the densification kinetics and grain growth behavior more efficiently than the microwave sintering (2.45 GHz, μS) process, resulting in better varistor characteristics for ZnO materials. However, sintering by millimeter-wave for too long period induces overfiring of the samples, which results in a density reversion phenomenon. Such a phenomenon leads to the decrease in surface state (Ns) and the potential barrier height (φb), which are presumed to be the mechanism leading to the degradation of ZnO materials' nonlinear properties.

Scopolamine and Pavlovian Fear Conditioning in Rats: Dose-Effect Analysis

Muscarinic-cholinergic antagonism produces learning and memory deficits in a wide variety of hippocampal-dependent tasks. Hippocampal lesions produce both acquisition deficits and retrograde amnesia of contextual fear (fear of the place of conditioning), but do not impact fear conditioning to discrete cues (such as a tone). In order to examine the effects of muscarinic antagonism in this paradigm, rats were given 0.01 to 100 mg/kg of scopolamine (or methylscopolamine) either before or after a fear conditioning session in which tones were paired with aversive footshocks. Fear to the context and the tone were assessed by measuring freezing in separate tests. It was found that pretraining, but not post-training, scopolamine severely impaired fear conditioning; methylscopolamine was ineffective in disrupting conditioning. Although contextual fear conditioning was more sensitive to cholinergic disruption, high doses of scopolamine also disrupted tone conditioning. Scopolamine did not affect footshock reactivity, but did produce high levels of activity. However, hyperactivity was not directly responsible for deficits in conditioning. It was concluded that scopolamine disrupts CS-US association formation or CS processing, perhaps through an attenuation of hippocampal theta rhythm.

Involvement of the lateral and dorsolateral amygdala in conditioned stimulus modality dependent two-way avoidance performance in rats.

Post-lesion learning and performance of shuttle-box avoidance and subsequent transfer to two warning signals (CSs) of different modality were investigated in 27 rats subjected either to a sham lesion (Group NORM), electrolytic injuries of the lateral amygdaloid nucleus (Group LAT), or combined lesions of the amygdalostriatal transition area and dorsolateral amygdala (Group D-LAT). All groups were divided into two subgroups according to warning signal sequences. In the first subgroup (D-DN-N sequence) the subjects were initially trained with the visual CS (darkness - D), then transferred to the more salient visual and auditory compound CS (darkness and noise - DN), and finally to the auditory CS alone (noise - N). The opposite arrangement of the CSs (N-ND-D sequence) was employed in the second subgroup. A small interference with shuttle-box learning, and no transfer deficit were seen in Group LAT, whereas D- LAT rats showed dramatically slow and inconsistent acquisition of avoidance responding followed by rapid weakening of performance during the training. In contrast to controls, in both lesioned groups avoidance and intertrial responding (ITR) were independent of the CS modality changes. The results indicate differential involvement of the lateral, and also of the dorsolateral amygdala, and amygdalostriatal transition area in CS processing, as well as in the mechanisms related to consolidation of the associations created during avoidance training.

MK-801 protects conditioned responses from extinction in the rabbit nictitating membrane preparation

MK-801 is a noncompetitive antagonist to N-methyl-d-aspartate (NMDA) receptors. MK-801 was given (0.05 or 0.10 mg/kg i.v.) to rabbits during extinction of a well-established conditioned response (CR) in the nictitating membrane preparation. The drug administration produced an immediate deficit in CR performance during extinction. However, when MK-801 administration was suspended, CRs reappeared immediately and showed no evidence of the previous extinction treatment. In addition, we confirmed previous findings that MK-801 impairs both the acquisition and the expression of CRs during CS—US training. A reduction in CS processing caused by MK-801 is the most parsimonious explanation of the data. There are also two-factor alternatives, which contend that MK-801 directly hinders associative formation and either directly blocks CR output or produces a state-dependent generalization decrement.

Emulsification of Calix[4]arenes Bearing Four Chains and Transportation of Cesium Ion through Liquid Surfactant-Membrane

Abstract Resorcinol-type calix[4]arenes bearing four alkyl side chains ([4]Ar-Rn) have been applied as a liquid surfactant-membrane in the concentration process of Cs+. [4]Ar-Rn formed a highly stable water-in-oil (w/o) emulsion for a mixture of toluene and HCl solution, and the w/o emulsion became a w/o/w emulsion by stirring it in a Cs+ solution. The Cs+ in the outer aqueous solution was transported through the liquid surfactant-membrane of w/o/w emulsion into the inner HCl solution. [4]Ar-R6 was the most effective emulsifier capable carrying Cs+ in the [4]Ar-Rn bearing alkyl chains of various lengths. The final amount of the transported Cs+ was 9 times as much as the molar of [4]Ar-R6 in 100 min at the initially 10 times molar Cs+ in the outer solution (turnover number: 9). Moreover, the Cs+ was transported selectively from a mixture of alkali metal ions (Cs+, Na+, and K+) by using 2 × 10−4 mol of [4]Ar-R6.

Cyclosporin-binding sites of murine sensitive and resistant lymphoid cell lines

Cyclosporin (Cs)-binding sites on murine spleen lymphocytes and on Cs-sensitive (CsS) and Cs-resistant (CsR) cloned lymphoma lines were compared using a ditritiated derivative of cyclosporin C (d3H-CsC). All three types of lymphocytes displayed similar d3H-CsC-binding characteristics. There were no major differences in the d3H-CsC-binding sites in terms of their cell surface density (number per surface area), their affinity and their specificity (capacity to discriminate between different Cs forms). The presence of the presumably membranous Cs-binding site is therefore insufficient to confer susceptibility to Cs, and resistance can thus be obtained at a post-receptor level. With the CsS clone, there was a general correlation between the Cs-specific binding capacity and the Cs-specific biological activity inasmuch as Cs which were weakly or not at all cytostatic bound only very poorly to the d3H-CsC-binding site. Such a correlation could not be established in the case of a mixed spleen cell population; which implies that, in such a system, Cs processing might play a role in its activity. Binding to the receptor may be an early but only a permissive step in the mechanism of action of Cs.