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1.
Soft Matter ; 16(48): 10860-10864, 2020 Dec 28.
Article in English | MEDLINE | ID: mdl-33242316

ABSTRACT

By measuring the increments of dielectric capacitance (ΔC) and dissipation (Δtan δ) during physical vapor deposition of a 110 nm film of a molecular glass former, we provide direct evidence of the mobile surface layer that is made responsible for the extraordinary properties of vapor deposited glasses. Depositing at a rate of 0.1 nm s-1 onto a substrate at Tdep = 75 K = 0.82Tg, we observe a 2.5 nm thick surface layer with an average relaxation time of 0.1 s, while the glass growing underneath has a high kinetic stability. The level of Δtan δ continues to decrease for thousands of seconds after terminating the deposition process, indicating a slow aging-like increase in packing density near the surface. At very low deposition temperatures, 32 and 42 K, the surface layer thicknesses and mobilities are reduced, as are the kinetic stabilities.

2.
Sci Rep ; 7(1): 7463, 2017 08 07.
Article in English | MEDLINE | ID: mdl-28785071

ABSTRACT

Ionic liquids are promising candidates for electrolytes in energy-storage systems. We demonstrate that mixing two ionic liquids allows to precisely tune their physical properties, like the dc conductivity. Moreover, these mixtures enable the gradual modification of the fragility parameter, which is believed to be a measure of the complexity of the energy landscape in supercooled liquids. The physical origin of this index is still under debate; therefore, mixing ionic liquids can provide further insights. From the chemical point of view, tuning ionic liquids via mixing is an easy and thus an economic way. For this study, we performed detailed investigations by broadband dielectric spectroscopy and differential scanning calorimetry on two mixing series of ionic liquids. One series combines an imidazole based with a pyridine based ionic liquid and the other two different anions in an imidazole based ionic liquid. The analysis of the glass-transition temperatures and the thorough evaluations of the measured dielectric permittivity and conductivity spectra reveal that the dynamics in mixtures of ionic liquids are well defined by the fractions of their parent compounds.

3.
Phys Chem Chem Phys ; 19(21): 14141-14147, 2017 May 31.
Article in English | MEDLINE | ID: mdl-28524925

ABSTRACT

Modern ionic liquids (ILs) are considered green solvents for the future applications due to their inherited advantages and remarkable transport properties. One of the ubiquitous properties of ILs is their intrinsic ionic conductivity. However, understanding of the super-Arrhenius behavior of the ionic conductivity process at elevated pressure still remains elusive and crucial in glass science. In this work, we investigate the ion transport properties of 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide: [C4mim][NTf2], 1-butylimidazolium bis[(trifluoromethyl)-sulfonyl]imide: [C4Him][NTf2] and 1-butylimidazolium hydrogen sulfate: [C4Him][HSO4] ILs in the supercooled liquid state using dielectric spectroscopy at ambient and high pressure. We present the experimental data in the dynamic window of the conductivity formalism to examine the charge transport properties. The frequency-dependent ionic conductivity data have been analyzed using the time-temperature superposition principle. In the Arrhenius diagram, the thermal evolution of the dc-conductivity reveals similar temperature dependence for both protic and aprotic ILs thus making it difficult to distinguish the ion dynamics. However, our results demonstrate the key role of high pressure that unambiguously separates the charge transport properties of protic ILs from aprotic ones through the apparent activation volume parameter. We also highlight that the activation volume can be employed to assess the information connecting the ability of ionic systems to form H-bond networks and the impact of proton transfer involved in the conduction process.

4.
Sci Rep ; 5: 13922, 2015 Sep 10.
Article in English | MEDLINE | ID: mdl-26355037

ABSTRACT

Ionic liquids (ILs) are salts that are liquid close to room temperature. Their possible applications are numerous, e.g., as solvents for green chemistry, in various electrochemical devices, and even for such "exotic" purposes as spinning-liquid mirrors for lunar telescopes. Here we concentrate on their use for new advancements in energy-storage and -conversion devices: Batteries, supercapacitors or fuel cells using ILs as electrolytes could be important building blocks for the sustainable energy supply of tomorrow. Interestingly, ILs show glassy freezing and the universal, but until now only poorly understood dynamic properties of glassy matter, dominate many of their physical properties. We show that the conductivity of ILs, an essential figure of merit for any electrochemical application, depends in a systematic way not only on their glass temperature but also on the so-called fragility, characterizing the non-canonical super-Arrhenius temperature dependence of their ionic mobility.

5.
J Econ Entomol ; 105(2): 533-9, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22606824

ABSTRACT

Using a quarterly (3-mo) monitoring and bait-replenishment interval, 122 subterranean termite colonies throughout the United States were baited with a refined cellulose bait matrix containing 0.5% noviflumuron. All colonies were eliminated in less than 1 yr after initiation of baiting as determined by long-term monitoring and genetic markers. Sixty-three percent of the colonies were eliminated during the first quarter after the initiation of baiting and 77% of colonies were eliminated after consuming two bait tubes or less. This suggests that a single baiting cycle and bait installed in response to a single active monitoring device were sufficient to eliminate the majority of colonies. Although termites temporarily abandoned stations after depleting bait, workers resumed feeding when baits were replenished. Colonies that consumed large amounts of bait before elimination foraged into multiple stations, thus allowing adequate amounts of bait to sustain feeding. The time to eliminate termite colonies with bait replenished quarterly was similar to that previously reported for laminated cellulose bait replenished monthly. Our data support the conclusion that extending the bait replenishment interval from monthly to quarterly for bait tubes with refined cellulose containing 0.5% noviflumuron did not adversely impact colony elimination.


Subject(s)
Benzamides , Hydrocarbons, Fluorinated , Insect Control/methods , Insecticides , Isoptera , Animals , Cellulose , Insect Control/instrumentation , Seasons , Species Specificity , Time Factors , United States
6.
Gesundheitswesen ; 65(12): 693-7, 2003 Dec.
Article in German | MEDLINE | ID: mdl-14685919

ABSTRACT

Children and adolescents abusing drugs present a special challenge for our health system. Special risks for the development of drug dependence are psychic diseases of parents, familial addiction or multiply burdened families. The treatment of drug-addicted children and adolescents in child and youth psychiatry requires a highly individualised therapy programme as well as a pedagogic and therapeutic setting corresponding to age. 745 patients were examined in a retrospective study between 1998 and 2001. The results are shown below. 68% of the patients had a relevant psychiatric second diagnosis, 39 Patients of the examined drug addicted children and adolescents were diagnosed with an additional psychotic disturbance. A study of children and youth psychiatry clinics in the fall of 2001 showed that sufficient clinical care for drug-addicted children and adolescents is still lacking.


Subject(s)
Substance-Related Disorders/therapy , Adolescent , Adult , Age Factors , Child , Diagnosis, Differential , Female , Hospitalization , Humans , Male , Mental Disorders/complications , Mental Disorders/diagnosis , Mental Disorders/therapy , Retrospective Studies , Risk Factors , Sex Factors , Substance-Related Disorders/complications , Substance-Related Disorders/diagnosis , Time Factors
9.
J Econ Entomol ; 94(1): 215-22, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11233117

ABSTRACT

Two formulations of spinosad (NAF-85 and NAF-371) were evaluated to determine the effect of concentration, deposit condition (dried, wet, or topical), and exposure time (0.1-10 h) for toxicant transfer among nestmates in the drywood termite Incisitermes snyderi (Light). Spinosad treatments were compared with two formulations of disodium octaborate tetrahydrate (DOT) (10% aqueous dilution, 98% dust) and with 35% calcium arsenate dust. Termites were dyed and individually exposed to different treatments for 0.1, 1.5,1.0, 5.0, 10.0 h, or 0.1 and 1.0 h (DOT and calcium arsenate dust) and then placed with 10 unmarked, untreated nestmates in a petri dish. Spinosad formulations also were evaluated by topical application to dyed termites. Transfer of lethal doses of toxicants between termites was indicated by significant mortality of untreated termites in 25 of 28 treatments by 28 d after introduction of dyed, treated termites. Only three treatments, one spinosad treatment (NAF-371, wet, 1 h) and both DOT 10% solution treatments, resulted in mortality of untreated termites that was not significantly different than that of water-treated controls. Two spinosad treatments and both calcium arsenate dust treatments resulted in >90% (94-98%) mortality of untreated termites by 28 d after introduction. Mortality of untreated termites was significantly different from controls for the two spinosad formulations, depending on condition of deposit and duration of dyed termite exposure to treatments.


Subject(s)
Drug Combinations , Insect Control/methods , Insecticides , Isoptera , Macrolides , Animals , Arsenates , Borates , Calcium Compounds , Isoptera/ultrastructure , Nymph
13.
Mod Hosp ; 108(67): 113-5, 1967 Jun.
Article in English | MEDLINE | ID: mdl-6044023
14.
Hosp Manage ; 102(4): 31-3, 1966 Oct.
Article in English | MEDLINE | ID: mdl-5918799
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