On the Initial Decay on Thermionic Emission from Oxide-Coated Cathodes

Using ordinary diodes and also diodes having a getter chamber, the initial decay of thermionic emission from oxide-coated cathodes over about 0.1 second was observed on the conditions of various cathode temperatures and also various anode voltages, and the change of initial decay was examined by keeping a cathode at high temperature and also by heating or cooling a getter deposit. As a result, it was found that by heat treatment of cathode at high temperature in the ordinary diode the initial decay of saturation current at observation temperature became slower than that before the treatment, that the decay characteristic could be restored to that before the treatment by applying high anode voltage and drawing out emission current, and that these phenomena similarly occurred also in the case of heating a getter deposit in both tubes. Also an initial decay of emission current more rapid than the initial decay of saturation current was found to occur at low anode voltages. In order to explain the above-mentioned phenomena, the poisoning of cathode due to residual gases was considered as the main cause of initial decay of saturation current, while the drop of anode potential caused by charging up of contamination on the anode was considered as the main cause of initial decay of emission current at low anode voltage

Temperature Dependence of Spectral Distribution with Activation of Thermionic Emission from (Ba-Sr) O Cathodes

Temperature dependence over about 750-850°K of several peaks appeared on spectral dependence over 0.6-3.5eV of thermionic emission from (Ba-Sr) O cathodes was observed with activation. Three kinds of the cathodes which were easy or difficult to activate were used as specimens. From the experiment on the three kinds of the cathodes, it was found that there were three stages in the activation process of (Ba-Sr) O cathodes, though total thermionic emission always increased with activation through the whole process. In the activation stage I, with activation, the maximum temperature of 3.2-eV peak shifted to higher temperature, though work function decreased and the intensity of each peak increased. In the stage II, with activation, work function increased on the contrary, the intensity of 3.2-eV peak decreased showing negative effect, and the maximum temperature of 3.2-eV peak shifted to lower temperature and then to higher one. In the stage III, with activation, work function decreased, the intensity of each peak increased, and the maximum temperature of each peak remarkably moved to lower temperature. From these results, it was clearly known that the earlier two stages were the abnormal stages and only the stage III was the normal activation stage

Experimental study on dynamic pipe fracture in consideration of hydropower plant model

AbstractIn the case of sudden valve closure, water hammer creates the most powerful pressure and damage to pipeline systems. The best way to protect the pipeline system is to eliminate water hammer. The main reasons for water hammer occurrence are valve closure, high initial velocity, and static pressure. However, it is difficult to eliminate water hammer. Water hammer tends to occur when the valve is being closed. In this study, the pipe fracture caused by static water pressure, gradually increasing pressure, and suddenly increasing pressure were compared experimentally in a breaking PVC test pipe. The quasi-static zone, the dynamic zone, and the transition zone are defined through the results of those experiments, with consideration of the fracture patterns of test pipes and impulses. The maximum pressure results were used to design the pipeline even though it is in the dynamic zone

Ambulatory Blood Pressure Is a Better Marker Than Clinic Blood Pressure in Predicting Cardiovascular Events in Patients With/Without Type 2 Diabetes

Background - The prognostic significance of ambulatory blood pressure (ABP) has not been established in patients with type 2 diabetes (T2DM). Methods - In order to clarify the impact of ABP on cardiovascular prognosis in patients with or without T2DM, we performed ABP monitoring (ABPM) in 1,268 subjects recruited from nine sites in Japan, who were being evaluated for hypertension. The mean age of the patients was 70.4 ± 9.9 years, and 301 of them had diabetes. The patients were followed up for 50 ± 23 months. We investigated the relation between incidence of cardiovascular diseases (CVDs) and different measures of ABP, including three categories of awake systolic blood pressure (SBP 150 mm Hg), sleep SBP (135 mm Hg), and dipping trends in nocturnal blood pressure (BP) (dippers, nondippers, and risers). Cox regression models were used in order to control for classic risk factors. Results - Higher awake and sleep SBPs predicted higher incidence of CVD in patients with and without diabetes. In multivariable analyses, elevated SBPs while awake and asleep predicted increased risk of CVD more accurately than clinic BP did, in both groups of patients. The relationships between ABP level and CVD were similar in both groups. In Kaplan–Meier analyses, the incidence of CVD in nondippers was similar to that in dippers, but risers experienced the highest risk of CVD in both groups (P < 0.01). The riser pattern was associated with a ∼150% increase in risk of CVD, in both groups. Conclusions - These findings suggest that ABPM is a better predictor of cardiovascular risk than clinic BP, and that this holds true for patients with or without T2DM

Longitudinal morphological changes during recovery from brain deformation due to idiopathic normal pressure hydrocephalus after ventriculoperitoneal shunt surgery.

The present study aimed to examine time-dependent change in cerebrospinal fluid distribution and various radiological indices for evaluating shunt effectiveness in patients with idiopathic normal pressure hydrocephalus (iNPH). This study included 54 patients with iNPH who underwent MRI before and after ventriculoperitoneal shunt surgery. The volume of the total ventricles and subarachnoid spaces decreased within 1 month after shunting. However, more than 1 year after shunting, the volume of the total ventricles decreased, whereas that of the total subarachnoid spaces increased. Although cerebrospinal fluid distribution changed considerably throughout the follow-up period, the brain parenchyma expanded only 2% from the baseline brain volume within 1 month after shunting and remained unchanged thereafter. The volume of the convexity subarachnoid space markedly increased. The changing rate of convexity subarachnoid space per ventricle ratio (CVR) was greater than that of any two-dimensional index. The brain per ventricle ratio (BVR), callosal angle and z-Evans index continued gradually changing, whereas Evans index did not change throughout the follow-up period. Both decreased ventricular volume and increased convexity subarachnoid space volume were important for evaluating shunt effectiveness. Therefore, we recommend CVR and BVR as useful indices for the diagnosis and evaluation of treatment response in patients with iNPH

Chromatographic formation of a triadic band of lithium in hydrated LTA zeolite: An investigation on lithium isotope separation effects by ion exchange

published online 12 April 2017Lithium concentrations [Li] and isotopic ratios [Li-7]/[Li-6] were measured for effluent fractions from a biphasic zeolite column. The biphasic state was ascribed to a mixture of hydrated Linde Type A (LTA) zeolites, [Li-0.008(NH4)(0.92)]A and [Li-0.33(NH4)(0.67)]A, which were formed by Li ion exchange from hydrated ammonium in the form (NH4)(12)[Al12Si12O48]center dot nH(2)O (NH(4)A). The biphasic Li band of the column was displaced by ion exchange with a solution of NH4NO3. A constant [Li] with a much lower level than the concentration of NHt(4)(_)(+) in the displacer (NH4NO3) was observed for the effluent from a short column. This constant lower level of [Li] was attributable to the biphasic state. On this [Li] plateau of the effluent, the level of [Li-7] shifted higher than the original isotopic composition of the Li feed, whereas Li-6 was concentrated on the biphasic zeolite solid. The accumulation of Li-6 in the zeolite proceeded by a mechanism of differential elution of Li-7 from the biphasic zeolite. For the long column experiment, a significant enrichment of Li-6 in the zeolite was observed, whereby a triadic band of Li was probably formed in the column. Two monophasic and a biphasic state were assigned. The biphasic band was deemed to push the monophasic bands forward, thereby enriching the monophasic bands with Li-7, while Li-6 accumulated at the end of the biphasic band. The trio structure of the Li band and isotopic discrimination in the band were analyzed. (C) 2017 Elsevier Inc. All rights reserved.ArticleMICROPOROUS AND MESOPOROUS MATERIALS. 248:115-121 (2017)journal articl

ソウヤ センジョウ ニ オケル デンカイ キョウド ソクテイ ケッカ

この報告は,短波帯の夜間における電界強度を測定した結果について述べたもので,若井氏が先に得た結果を再検討したもので,肯定的な結果が得られた.測定は東京からCape Townに至る船上においてなされたもので,結果は10Mc/s帯においては減衰量が少なく,又各周波数帯に規則的な関係は得られなかったが,2.5Mc/sのJJYの受信結果から求めた減衰量は,垂直投射に換算して1.0dbなる値を得た.これは,若井氏によって求められた値1.7dbに対して60%位の値であるが,測定値がばらつき,又往路と復路で若干測定値に差があるので数量的な点ではいずれを採ったらいいかは断定できない.一方2.5Mc/sにおいては,遠距離における観測点が少ないので,測定した周波数帯全部についてこれを2.5Mc/sの垂直投射に換算して,加重平均を求めてみると,2.5dbなる値を得た.得られた値を再び2.5Mc/sの測定値に当てはめてみると,1回反射の限界距離内では極めてよく合うことがわかった.This paper describes the result of the , field intensity measurement of HF waves which was carried out at night on the way from Tokyo to Cape Town on board the "SOYA". Field intensities measured were lower than those of the so-called "unabsorbed field intensity" and the lower the frequency, the more rapidly the field intensity decreases with the distance of transmission. Hence, it is suggested that the non-deviative absorption must be taken into consideration. From the measurement on 2.5Mc/s wave, it was derived that the nondeviative absorption converted into the vertical incidence was equal to 1.0db. On the other hand, the weighted mean value for all frequencies measured was 2.5db. The difference between these values is examined herein

Pregabalin withdrawal in patients without psychiatric disorders taking a regular dose of pregabalin: A case series and literature review

Pregabalin is a drug that can cause psychiatric symptoms via pregabalin withdrawal. Prior reports on pregabalin withdrawal have mainly focused on cases with pregabalin dependence or abuse, and little attention has been paid to patients who are prescribed regular doses of pregabalin. Herein, we report three cases of pregabalin withdrawal in patients without psychiatric disorders, taking regular doses of pregabalin, who developed psychiatric symptoms such as insomnia and anxiety after abrupt discontinuation of pregabalin. In addition, we conducted a systematic review of six case reports (previous studies) of pregabalin withdrawal under regular doses of pregabalin. Among the six cases, three patients had no comorbid mental or substance use disorders, the dose of pregabalin ranged from 150 to 600 mg/d, and the duration of pregabalin use ranged from a few weeks to many years. Of these six cases of pregabalin withdrawal, five had psychopathological symptoms, three had vegetative symptoms, and three had neurologic and physical complications. We concluded that since pregabalin withdrawal can occur even with regular doses and short-term use, clinicians must carefully reduce pregabalin doses when reducing or discontinuing treatment, paying close attention to withdrawal symptoms. Our case series sheds light on the scant evidence from previous research on physical dependence in patients who are taking regular doses of pregabalin. Furthermore, our cases were also valuable in demonstrating that pregabalin withdrawal can occur even after a relatively short period of 2 months

Nocturnal nondipping of heart rate predicts cardiovascular events in hypertensive patients

Objective: It has not been established whether nocturnal nondipping of heart rate (HR) predicts future cardiovascular disease (CVD). We performed this study to test the hypothesis that nocturnal nondipping of HR predicts the risk of incident CVD independent of nocturnal blood pressure dipping pattern. Methods: Ambulatory blood pressure monitoring was performed in 457 uncomplicated patients, who were being treated or evaluated for hypertension. They were followed for an average of 72 ± 26 months. Nondipping HR was defined as a night/day HR ratio greater than 0.90. We chose two outcomes for this analysis: CVD events (defined as stroke, myocardial infarction, or sudden cardiac death) and all-cause mortality. Cox regression analyses (stepwise method) were used to estimate hazard ratios and their 95% confidence interval after adjusting for covariates. Results: In univariate analysis, increased sleep HR and nondipping of HR were associated with increased risk of CVD and all-cause mortality, but awake HR was not. In multivariable analyses, HR nondipping status significantly predicted an increased risk of CVD events (hazard ratio, 2.37; 95% confidence interval, 1.22–4.62; P = 0.01), but not for all-cause mortality. Increased 24-h HR was significantly associated with increased risk of all-cause mortality (hazard ratio, 1.67; 95% confidence interval, 1.11–2.51; P = 0.01). Conclusion: The risk of future CVD was shown to be 2.4 times higher in those whose HR does not exhibit the typical nocturnal decline. The relationship was independent of nondipping of SBP and was not dependent on diabetes status or blood pressure level

Night Time Blood Pressure Variability Is a Strong Predictor for Cardiovascular Events in Patients With Type 2 Diabetes

Background: We aimed this study to test the hypothesis that short-term blood pressure (BP) variability and abnormal patterns of diurnal BP variation, evaluated by ambulatory BP (ABP), predicts risk of incident cardiovascular disease (CVD) in patients with type 2 diabetes (T2DM). Methods: ABP monitoring (ABPM) was performed in 300 patients with uncomplicated T2DM without known CVD and without BP medications, who were followed for 54 ± 20 months. The relationships of different measures of BP variability, the presence of abnormal patterns of diurnal BP variation (nondipper, riser, or morning BP surge) and the standard deviations of awake and asleep ABP were determined. Cox proportional hazards models were used to estimate hazard ratios (HRs) and their 95% confidence intervals (CIs) before and after controlling for various covariates. Results: The mean age was 67.8 ± 9.6 years, 48% were male, 253 (84%) had a diagnosis of hypertension, and the mean of the standard deviations of awake systolic BP/diastolic BP (SBP/DBP) were 18 ± 6/11 ± 4 mm Hg, and those of sleep SBP/DBP were 13 ± 5/9 ± 3 mm Hg. During follow-up, there were 29 cardiovascular events. In multivariable analyses, the standard deviations of sleep SBP (HR = 1.08; 95% CI, 1.01–1.16, P < 0.05) and sleep DBP (HR = 1.13; 1.04–1.23, P < 0.01) were independently associated with incident CVD. Neither the nondipper and riser patterns nor the morning BP surge were associated with incident CVD events independently of clinic and 24-h BP levels. Conclusions: Abnormal diurnal BP variation was not a predictor of CVD in patients with T2DM. Night time BP variability was an independent predictor of future incidence of CVD, suggesting that this measure could reflect pathophysiology of T2DM