Crystallisation temperature control of stoichiometry and selectivity in host–guest compounds

CrystEngComm ◽  
2017 ◽  
Vol 19 (39) ◽  
pp. 5892-5896 ◽  
Author(s):  
Nicole M. Sykes ◽  
Hong Su ◽  
Edwin Weber ◽  
Susan A. Bourne ◽  
Luigi R. Nassimbeni
Keyword(s):  
Temperature Control ◽  
Low Temperatures ◽  
Tertiary Butanol ◽  
Crystallisation Temperature

A bulky diol host is only selective for tertiary butanol when versus 2-propanol at low temperatures.

Equipment for Preparing Electropolished TEM Specimens at Controlled and Low Temperatures

1987 ◽  
Vol 115 ◽  
Author(s):  
Vjekoslav Franetovic
Keyword(s):  
Stainless Steel ◽  
Temperature Control ◽  
Low Temperatures ◽  
Control Unit ◽  
Cooling Device ◽  
Dry Ice ◽  
Temperature Control Unit ◽  
Copper Coil ◽  
Heat Buildup

ABSTRACTA cooling device for use with the Fishione twin-jet electropolisher Model 110 has been developed for electropolishing TEM specimens at controlled and low temperatures necessary for some materials. This consists of an explosion-proof pump circulating methanol through a specially designed stainless steel bath, and a copper coil immersed in a mixture of methanol and dry ice in a dewar. A thermocouple with a temperature control unit provides precise temperature control.With this device, electropolishing can be conducted at temperatures as low as −55°C. This allows electropolishing of certain materials which cannot be polished with conventional equipment. The precisely controlled temperature also improves the performance of the electropolishing equipment at all temperatures because the success of electropolishing depends on maintaining constant conditions during the process. The unit further allows the use of aggressive electrolytes and preparation of solutions which could otherwise become hazardous due to heat buildup during electropolishing or preparation.

scholarly journals Crystallisation temperature control of stoichiometry and selectivity in host–guest compounds

CrystEngComm ◽  
2017 ◽  
Vol 19 (44) ◽  
pp. 6719-6719
Author(s):  
Nicole M. Sykes ◽  
Hong Su ◽  
Edwin Weber ◽  
Susan A. Bourne ◽  
Luigi R. Nassimbeni
Keyword(s):  
Temperature Control ◽  
Crystallisation Temperature

Correction for ‘Crystallisation temperature control of stoichiometry and selectivity in host–guest compounds’ by Nicole M. Sykes et al., CrystEngComm, 2017, 19, 5892–5896.

scholarly journals Photopreiodic and Temperature Control of Flower Initiation in the Late Pea Cultivar Greenfeast

1968 ◽  
Vol 21 (4) ◽  
pp. 609 ◽  
Author(s):  
DM Paton
Keyword(s):  
Temperature Control ◽  
Low Temperatures ◽  
Continuous Light ◽  
Flower Initiation ◽  
Temperature Responses

The number of green foliage leaves at initiation is related to a quantitative leaf requirement for flowering in the late pea cultivar Greenfeast. When grown in various temperature and photoperiod regimes the leaf requirement is least in continuous light and low temperatures. The additive nature of the photoperiodic and temperature responses suggests that photoperiod and temperature probably act independently.

scholarly journals Limited specificity of SARS-CoV-2 antigen-detecting rapid diagnostic tests at low temperatures

2021 ◽  
Author(s):  
Verena Haage ◽  
Andres Moreira-Soto ◽  
Jilian A. Sacks ◽  
Victor Corman ◽  
Christian Drosten ◽  
...  
Keyword(s):  
Health Care ◽  
Temperature Control ◽  
False Positive ◽  
Low Temperatures ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Health Care Settings ◽  
Positive Results

AbstractSARS-CoV-2 antigen-detecting rapid diagnostic tests (Ag-RDTs) are available within and outside of health care settings to enable increased access to COVID-19 diagnosis. These environments include provisional testing facilities, lacking temperature control; as outside temperatures fall, recommended testing temperatures cannot be guaranteed. We report impaired specificity in two out of six Ag-RDTs when used at 2-4°C, indicating that testing in cold settings might cause false-positive results potentially entailing unwarranted quarantine assignments and incorrect incidence estimates.

scholarly journals The Effect of Vernalization on the Appearance of Local Amaryllis (Hippeastrum sp.) Plants in the Land of Karo and West Sumatera

1970 ◽  
Vol 6 (1) ◽  
pp. 24-33
Author(s):  
Ulfa Ridha Andini ◽  
Hot Setiado ◽  
Luthfi Aziz Mahmud Siregar
Keyword(s):  
Plant Breeding ◽  
Temperature Control ◽  
Low Temperatures ◽  
Room Temperature ◽  
Economic Value ◽  
Control Treatment ◽  
West Sumatra ◽  
North Sumatra ◽  
And Storage

Amarilis is one of the flower of the park that is attractive and has high economic value. This study aims to determine the effect of vernalization on the appearance of local amaryllis plants in Tanah Karo and West Sumatra. This research was conducted at the Plant Breeding Basic Laboratory of the Faculty of Agriculture, University of North Sumatra, Medan, from February 2018 to July 2018. This research was carried out by storing tubers at room temperature (control) and storage of tubers at low temperatures (vernalization) at 10 oC for 6 weeks, and with differences in accession of plants namely G1 (Accession of West Sumatra Payakumbuh), G2 (Bukit Tinggi West Sumatra Accession), G3 (Padang Panjang West Sumatra Accession), G4 (Local Kabanjahe Accession Tanah Karo), G5 (Berastagi Local Accession Tanah Karo ), G6 (Tanah Karo Local Accession Accession). The results showed that vernalization gave a different appearance compared to the control treatment.

ON THE HYDROGENATION OF BITUMEN FROM THE BITUMINOUS SANDS OF ALBERTA II

1931 ◽  
Vol 4 (5) ◽  
pp. 517-539 ◽  
Author(s):  
E. H. Boomer ◽  
A. W. Saddington
Keyword(s):  
Adverse Effect ◽  
Temperature Control ◽  
Low Temperatures ◽  
Coke Formation ◽  
Absolute Rate ◽  
Rate Of Reaction ◽  
Series Of Experiments ◽  
Distillation Residues ◽  
Time Required ◽  
Repeated Runs

A second series of experiments on the batch hydrogenation of McMurray bitumen has been carried out. A cylindrical autoclave, of 1.8 litres capacity and designed for close temperature control and efficient agitation, is described.Hydrogenation of the larger part of the bitumen proceeded with ease and commenced at comparatively low temperatures. The rate of hydrogenation was dependent on temperature, presence of a catalyst and extent of hydrogenation. The reaction commenced slowly at 200 °C. and increased with rising temperature. The presence of molybdic anhydride approximately doubled the rate of reaction. The extent and rate of hydrogenation decreased on repeated runs with the same lot of bitumen due to the adverse effect of an increasing proportion of simple hydrocarbons.An increase in the relative amount of hydrogen to bitumen increased the absolute rate of reaction and degree of hydrogenation possible in one treatment. As a result of the shorter time required, coke formation was largely suppressed.Experiments on distillation residues from hydrogenated bitumen reveal the presence in bitumen of some 15% of asphaltic material which is very resistant to hydrogenation or cracking at temperatures as high as 500 °C. This material has not yet been hydrogenated without considerable coke formation but the problem does not appear to be insoluble.It appears that 75% of Alberta bitumen may be converted easily to gasoline and oil.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

Sign in / Sign up

Export Citation Format

Share Document