scholarly journals Experiments on the emission of electrons under the influence of chemical action

1924 ◽  
Vol 105 (732) ◽  
pp. 468-480 ◽  
Keyword(s):  
Liquid Alloy ◽  
Characteristic Curve ◽  
Low Pressure ◽  
Quantitative Information ◽  
Chemical Action ◽  
Sodium And Potassium

Several investigators have claimed that electrons are emitted from metals under the influence of chemical action. It was shown by Haber and Just that drops of liquid cæsium or the liquid alloy of sodium and potassium emit electrons when acted on, at a low pressure, by a number of chemically active gases. Prof. Richardson investigated the phenomena with a view to obtaining quantitative information. He determined the characteristic curve for the emission from drops of a liquid alloy of sodium and potassium when acted on, at a low pressure, by Cl 2 , COCI 2 and H 2 O. He also showed that the distribution of energy among the emitted electrons obeyed Maxwell's Law.

scholarly journals The emission of electrons under the influence of chemical action

1931 ◽  
Vol 132 (819) ◽  
pp. 22-50 ◽  
Keyword(s):  
Melting Point ◽  
Energy Distribution ◽  
Liquid Alloy ◽  
Contact Potential Difference ◽  
Potential Difference ◽  
Contact Potential ◽  
Chemical Action ◽  
Upper Limits ◽  
Low Pressures ◽  
Sodium And Potassium

The present investigation is a continuation of the researches on the emission of electrons under the influence of chemical action listed in the footnote. In the remainder of this paper these publications will be referred to by the numbers assigned to them in this list. All the experiments to be described were made with a liquid alloy of the composition NaK 2 , which has the lowest melting point of all the alloys of sodium and potassium, under the action of phosgene gas (COCi 2 ). At the beginning the pre-existing situation was carefully reviewed. It was felt that the most important point was to determine the energy distribution of the emitted electrons at pressures of COCl 2 less than 10 -4 mm. with as much accuracy and down to as low pressures as possible. In (6) it had only been found possible to make rough estimates of this energy distribution owing to troublesome variations in the contact potential difference between the electrodes which it was impossible to control. Another unsatisfactory feature of (6) was the “clean-up” effect of the alloy on the reacting gas. This made the real values of the pressures very uncertain, particularly at the lower pressures, so much so that the values were only given in the paper as upper limits.

scholarly journals I. The emission of electrons under the influence of chemical action

1922 ◽  
Vol 222 (594-604) ◽  
pp. 1-43 ◽  
Keyword(s):  
Electromotive Force ◽  
Quantitative Information ◽  
Interesting Phenomenon ◽  
Chemical Action ◽  
Spherical Source ◽  
Spherical Electrode ◽  
The Subject ◽  
Set Up ◽  
The Individual ◽  
Sodium And Potassium

1.—Several investigators have claimed that electrons are emitted from metals under the influence of chemical action, but the only claim which seems well substantiated is that of Haber and Just, who found that when drops of cæsium or of the liquid alloy of sodium and potassium are attacked, at a low pressure, by a number of chemically active gases, the drops lose a negative but not a positive electric charge. The electric currents set up with the drops negatively charged are stopped by the application in a suitable manner of relatively small magnetic fields. This shows that the currents are carried by electrons emitted from the drops. The object of the present investigation has been to obtain quantitative information about this interesting phenomenon, and, more especially, to ascertain the magnitude of the kinetic energy of the emitted electrons and the mode of its distribution among them. The importance of the subject lies in the fact that it is the only way, so far as I am aware, in which any information at all can be made available as to the distribution of energy among the individual products—molecular, atomic, ionic or electronic—of a chemical reaction. The majority of the experiments have been directed towards obtain­ing the curves showing the relation between the chemical electron current and the applied electromotive force for the case of a small spherical source concentric with a large spherical electrode.

scholarly journals The emission of electrons under the influence of chemical action. Part III.—The action of Cl 2 , Br 2 , I 2 , NOCl, HCl, N 2 O, and COS on NaK 2

1934 ◽  
Vol 145 (854) ◽  
pp. 18-51
Keyword(s):  
Chemical Reaction ◽  
Liquid Alloy ◽  
Electron Emission ◽  
Vapour Pressure ◽  
Atmospheric Pressure ◽  
Chemical Action ◽  
Sodium And Potassium

The two preceding papers, which will be referred to in the sequal as Part I and Part II, dealt chiefly with a detailed investigation of the electron emission when the liquid alloy of sodium and potassium of the composition NaK 2 is acted on by Phosgene (COCl 2 ). The latter substance was chosen for this purpose mainly because it is comparatively easy to manipulate on account of its extremely low vapour pressure at the temperature of liquid air and almost atmospheric pressure at room temperatures. A number of the conclusions in Part II were based on the results of unpublished experiments with other gaseous reagents. Some of these are described in the present paper. After the completion of most of the experiments described in Part I and Part II the further investigation of the phenomenon of chemical electron emission was directed towards clearing up (1) the effect of the mechanism of the chemical reaction; (2) the connection between the amount of energy available in the reaction and the energy of the electrons emitted; and (3) the changes caused by varying the nature of the molecules taking part in the reaction.

scholarly journals The Distribution of Gas and Liquid within the Cuttlebone

1961 ◽  
Vol 41 (2) ◽  
pp. 365-381 ◽  
Author(s):  
E. J. Denton ◽  
J. B. Gilpin-Brown
Keyword(s):  
Sea Water ◽  
Low Pressure ◽  
Average Value ◽  
Left Behind ◽  
Gas Space ◽  
Neutrally Buoyant ◽  
Sodium And Potassium

The newest chamber of a cuttlebone is always incomplete and full of a watery solution. This contains sodium and potassium in concentrations close to those of sea water.The second newest chamber contains a gas space and sometimes contains liquid. This liquid is rarely localized at the siphuncular end of the chamber. It is not certain that liquid is initially extracted through the siphuncular wall of the chamber, although this is possible.When liquid is pumped out of a newly formed chamber the salt which it initially contains is not left behind, either free or bound into the structure of the bone.The 3rd to about the 10th newest chambers usually contain no visible liquid. But their siphuncular walls are permeable to liquid and liquid does enter these chambers when the cuttlebone becomes very dense.At cuttlebone densities around 0·6, i.e. close to values which will make the cuttlefish neutrally buoyant, the older and more posterior chambers are almost full of liquid. This liquid can, however, be pumped out. When a cuttlebone has a density around 0·5 very little liquid can be seen in any of its chambers.The pressure of gas within a newly ‘pumped out’ chamber is very low, but by the time a chamber has become the ninth newest the pressure of gas is close to the average value for the whole cuttlebone, i.e. about 0·8 atm.The low pressure of gas found in the newest chambers is explained by the slowness with which gas diffuses into a space created by the active removal of liquid.

Clearance of edema fluid into cerebrospinal fluid

1978 ◽  
Vol 48 (5) ◽  
pp. 754-764 ◽  
Author(s):  
Hans J. Reulen ◽  
Matsutaira Tsuyumu ◽  
Anne Tack ◽  
Andreas R. Fenske ◽  
George R. Prioleau
Keyword(s):  
High Pressure ◽  
Cerebrospinal Fluid ◽  
Low Pressure ◽  
Primary Method ◽  
Content Type ◽  
Edema Fluid ◽  
Ventriculocisternal Perfusion ◽  
Sodium And Potassium ◽  
Fine Print ◽  
Edematous Brain

✓ The authors present the results of an investigation studying the resolution of vasogenic brain edema using cold injury in cats. The appearance of RISA-I131 and sucrose-C14 labeled edema fluid in the ventricular cerebrospinal fluid (CSF) was assessed by means of ventriculocisternal perfusion. The effect of low- or high-pressure perfusion on edema spread was determined by measuring the water, sodium, RISA-I131, and sucrose-C14 content of serial tissue blocks taken from the injured cortex through the white matter to the ventricular ependyma. The findings indicate that increasing the hydrostatic pressure gradient between edematous brain and CSF enhances the clearance of edema fluid into the ventricular CSF. This was conclusively demonstrated with low-pressure ventricular perfusion which markedly diminished the amount of edema close to the ventricles compared to the controls. The concentration of albumin, sodium, and potassium in the fluid removed from the tissue during low-pressure perfusion indicates that bulk flow was the primary method of edema movement through the extracellular space. With high-pressure perfusion the concentration profiles suggested alternative mechanisms of edema resolution, such as diffusion and reabsorption into capillaries.

scholarly journals A Low-Dose CT-Based Radiomic Model to Improve Characterization and Screening Recall Intervals of Indeterminate Prevalent Pulmonary Nodules

Diagnostics ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1610
Author(s):  
Leonardo Rundo ◽  
Roberta Eufrasia Ledda ◽  
Christian di Noia ◽  
Evis Sala ◽  
Giancarlo Mauri ◽  
...  
Keyword(s):  
Early Detection ◽  
Predictive Value ◽  
Low Dose ◽  
Low Cost ◽  
Characteristic Curve ◽  
Model Performance ◽  
Pulmonary Nodules ◽  
Quantitative Information ◽  
Test Dataset ◽  
Screening Programs

Lung cancer (LC) is currently one of the main causes of cancer-related deaths worldwide. Low-dose computed tomography (LDCT) of the chest has been proven effective in secondary prevention (i.e., early detection) of LC by several trials. In this work, we investigated the potential impact of radiomics on indeterminate prevalent pulmonary nodule (PN) characterization and risk stratification in subjects undergoing LDCT-based LC screening. As a proof-of-concept for radiomic analyses, the first aim of our study was to assess whether indeterminate PNs could be automatically classified by an LDCT radiomic classifier as solid or sub-solid (first-level classification), and in particular for sub-solid lesions, as non-solid versus part-solid (second-level classification). The second aim of the study was to assess whether an LCDT radiomic classifier could automatically predict PN risk of malignancy, and thus optimize LDCT recall timing in screening programs. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), accuracy, positive predictive value, negative predictive value, sensitivity, and specificity. The experimental results showed that an LDCT radiomic machine learning classifier can achieve excellent performance for characterization of screen-detected PNs (mean AUC of 0.89 ± 0.02 and 0.80 ± 0.18 on the blinded test dataset for the first-level and second-level classifiers, respectively), providing quantitative information to support clinical management. Our study showed that a radiomic classifier could be used to optimize LDCT recall for indeterminate PNs. According to the performance of such a classifier on the blinded test dataset, within the first 6 months, 46% of the malignant PNs and 38% of the benign ones were identified, improving early detection of LC by doubling the current detection rate of malignant nodules from 23% to 46% at a low cost of false positives. In conclusion, we showed the high potential of LDCT-based radiomics for improving the characterization and optimizing screening recall intervals of indeterminate PNs.

T2 mapping in orbital masses: preliminary study on differential diagnostic ability of T2 relaxation time

2019 ◽  
Vol 61 (5) ◽  
pp. 668-674
Author(s):  
Yan Zhou ◽  
Xiao-Quan Xu ◽  
Hao Hu ◽  
Guo-Yi Su ◽  
Hu Liu ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Predictive Value ◽  
T2 Mapping ◽  
Characteristic Curve ◽  
Preoperative Assessment ◽  
Diagnostic Value ◽  
Quantitative Information ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Orbital Masses

Background T2 mapping has been proven to be useful in tumor characterization. As to orbital masses, its diagnostic value needs to be investigated. Purpose To evaluate the usefulness of T2 mapping in orbital masses and the ability of T2 relaxation time in differentiating malignant from benign orbital masses. Material and Methods Forty-seven patients with solid orbital masses (33 benign and 14 malignant) who underwent T2 mapping examination for preoperative assessment were enrolled in the current study. T2 mapping was acquired using 16 TE values (range 12–192 ms; delta TE 12 ms). Mean T2 relaxation time was calculated based on the whole mass region of interest and compared between the malignant and benign groups using the unpaired t-test. Receiver operating characteristic curve analysis was adopted to calculate its diagnostic value. Results Malignant orbital masses showed significantly lower T2 relaxation time than benign masses (76.4 ± 13.0 ms vs. 119.1 ± 20.4 ms; P < 0.001). If setting a T2 relaxation time of 89.5 ms as the threshold value, optimal differentiating performance could be achieved (area under the curve 0.936; sensitivity 100.0%; specificity 87.9%; accuracy 91.5%; positive predictive value 77.8%; negative predictive value 100%). Conclusion T2 mapping and its derived T2 relaxation time could provide quantitative information and serve as a supplementary imaging marker for differentiating malignant from benign orbital masses.

scholarly journals Flow and Noise Characteristics of Centrifugal Fan in Low Pressure Environment

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 985 ◽  
Author(s):  
Xilong Zhang ◽  
Yongliang Zhang ◽  
Chenggang Lu
Keyword(s):  
Ambient Pressure ◽  
Characteristic Curve ◽  
Normal Pressure ◽  
Low Pressure ◽  
Centrifugal Fan ◽  
Working Process ◽  
Fan Noise ◽  
Environmental Pressure ◽  
Noise Characteristics ◽  
Consumption Curve

The influence of low-pressure environment on centrifugal fan’s flow and noise characteristics was studied experimentally and numerically. A testbed was established to conduct the experimental test on the performance of a centrifugal fan, and the characteristic curve and power consumption curve of the fan under different pressure were obtained. Then the simulation model of the centrifugal fan was established, which was used to simulate the working process of centrifugal fan under different negative pressures. The results showed that the total pressure and static pressure of the fan decrease with the decrease of the ambient pressure. The total and static pressures of the fan under 60 kPa pressure condition decreased by 42.3% and 38.3%, respectively, compared with those of fan under the normal pressure. The main reason for this phenomenon is that the decrease of the environmental pressure leads to the decrease of air density. Besides, with the drop of environmental pressure, the sound pressure and sound power of the fan noise decreases.

scholarly journals Absorption of gases in the discharge tube

1914 ◽  
Vol 90 (621) ◽  
pp. 499-506 ◽  
Keyword(s):  
Sulphuric Acid ◽  
Liquid Alloy ◽  
Discharge Tube ◽  
Convenient Method ◽  
Chemical Compounds ◽  
High Tension ◽  
Rate Of Absorption ◽  
Oliver Lodge ◽  
Sodium And Potassium ◽  
A Current

Mey has shown that when the liquid alloy of sodium and potassium is made the cathode in a discharge tube, then, on passage of a current, if the gases nitrogen and hydrogen are present they are absorbed. The inactive gases, such as helium, are not affected, however, so he concludes that this would form a very convenient method for the preparation of helium where hydrogen and nitrogen are present as impurities. He mentions the rate of absorption compared with the quantity of electricity passing, and it is much larger than the absorption of gases by the walls of the discharge tube during the passage of a discharge. It is thought that the gases form chemical compounds with the sodium and potassium–the nitrogen giving the nitride and hydrogen the hydride. The following experiments were made to see if there were any relation between the amount of gas absorbed and the quantity of electricity passing during discharge—the measurements being made with varying pressures of the gas. In order to measure the electricity a small voltameter containing sulphuric acid was employed, and the quantity of hydrogen evolved in it was compared with the amount of gas absorbed. The current employed had to be a uni-directional high-tension one. For this, and induction coil with an Oliver Lodge value in the secondary was used. Provided the current was not too large this arrangement gave satisfactory results.

Some Results of the Spectroscopic Study of Four Close Binary Systems of Early Spectral Types

1965 ◽  
Vol 5 ◽  
pp. 120-130
Author(s):  
T. S. Galkina
Keyword(s):  
Spectroscopic Study ◽  
Spectral Type ◽  
Spectroscopic Investigation ◽  
Binary Systems ◽  
Quantitative Information ◽  
Close Binary ◽  
Physical Parameters ◽  
Absorption And Emission ◽  
Close Binary Systems ◽  
Quantitative Estimates

It is necessary to have quantitative estimates of the intensity of lines (both absorption and emission) to obtain the physical parameters of the atmosphere of components.Some years ago at the Crimean observatory we began the spectroscopic investigation of close binary systems of the early spectral type with components WR, Of, O, B to try and obtain more quantitative information from the study of the spectra of the components.

Sign in / Sign up

Export Citation Format

Share Document