Emission of High Energy Electrons during Mechanical Treatment of Alkali Halides

Wollbrandt, J.; Linke, E.; Meyer, Kurt W.

doi:10.1002/pssa.2210270245

Cited by 29 publications

(4 citation statements)

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“…31 Right after cleavage, the crystals are heated to 480 K for 1 h to remove surface charges. 32 For experiments between 110 K and room temperature, the sample is cooled with liquid nitrogen. To reduce thermal drift, we usually wait for 2 h after attaching the cooling copper block to the sample before acquiring the first image.…”

Section: Methodsmentioning

confidence: 99%

Clear Signature of the (2 × 1) Reconstruction of Calcite (101̅4)

et al. 2010

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Calcite is a mineral of fundamental importance that plays a crucial role in many fields of research such as biomineralization, biomolecule adsorption, and reactivity as well as industrial and daily life applications. Consequently, the most stable cleavage plane of calcite has been studied extensively using both direct imaging techniques such as atomic force microscopy as well as spectroscopic and diffraction techniques. Several surface structures have been reported for the (1014) cleavage plane of calcite differing from the simple bulk-truncated structure and an ongoing controversy exists in literature whether the cleavage plane exhibits a (2 x 1) reconstruction or not. We study the (1014) cleavage plane using high-resolution noncontact atomic force microscopy (NC-AFM) under ultrahigh vacuum conditions and obtain a clear signature of the (2 x 1) reconstruction. This reconstruction is observed in very narrow tip-surface distance ranges only, explaining why in some experiments the reconstruction has been observed and in others not. Moreover, as all sample preparation is performed in ultrahigh vacuum, the possibility of the (2 x 1) reconstruction being adsorbate-induced appears rather unlikely. Additionally, tip-induced surface changes are ruled out as origin for the observed reconstruction either. In conclusion, our study suggests that the (2 x 1) reconstruction is a true surface property of the (1014) cleavage plane of calcite.

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Section: Methodsmentioning

confidence: 99%

Clear Signature of the (2 × 1) Reconstruction of Calcite (101̅4)

et al. 2010

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“…have been shown to be present, bearing elementary charge densities of 10 8 to 10 10 e cm -2 [8]. These charged patches may consist of vacancies [8].…”

Section: Vacancy Of Kieseritementioning

confidence: 98%

“…have been shown to be present, bearing elementary charge densities of 10 8 to 10 10 e cm -2 [8]. These charged patches may consist of vacancies [8]. It is remarkable that the given surface density range is commensurable with that of elementary charges transferred in the course of contact charging of alkali halide crystals [5], proving a possible correlation between surface vacancies and contact charging.…”

Section: Vacancy Of Kieseritementioning

confidence: 98%

Electrostatic Processing of Mineral Salt Mixtures: The Selectively‐stimulated Contact Charging of Kieserite (MgSO₄ · H₂O). An Interpretation

Ernst

1990

Ber Bunsenges Phys Chem

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In th~electrostatic processing o~crude potash salt, a mixture of mainly KCl, NaCI and MgS0 4 · H 20, the single salt particles gain an electnc charge component-selectively on contact with each other. This enables the components to be separated in an electric field. The component-selective stimulation of contact charging can be achieved using a technology developed over many years, where small amounts of certain monocarboxylic acids are added to the salt mixture, while the relative humidity of the ambient air is maintained at some ?efimte value. -Recently a model has been proposed to elucidate the mechanism of stimulated contact charging. It has been applied In the case o~NaCI. H 20 molecules bonded in surface-cation-vacancies of the crystal have an important role in this model, which will b~extended In the 'p~esent work to th~case of the s~imulated contact charging of kieserite. This enables the interpretation of empirical diagrams characterising the electrostatic salt separation to be made for the first time. Conversely, this may be regarded as a convincing verification of the model itself.

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“…Some of these exo-electrons can be quite energetic. Of the exo-electrons from fractured mica, 20% have energies in excess of 150 eV, and around 10% have energies in excess of 350 eV; from the fracture of polybutadiene containing glass beads, around 5% has energies in excess of 100 e V, and a sm aller fraction has energies measured to 500 eV; Wollenbrandt et al (7) have measured exo-electrons with energies as high as 120 keV from alkali halides. Therefore, it is conceivable that exo-electrons could initiate deflagration.…”

Section: Introductionmentioning

confidence: 99%

Impact Sensitivity Reduction Via Exo‐Electron Control

Rhein

Reed

1993

Propellants Explo Pyrotec

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Reduzierung der Schlagempfindlichkeit über eine Kontrolle durch Exo-ElektronenVi ele Materi alien emittieren beim Bruch Elektronen (Exo-Elektronen) in ein em sogn. F rakto-Emi ss ionsprozeß. Be i Substanze n ode r Mi schungen, di e defl agrieren oder detonieren können durch Stoß oder Reibung, können diese Exo-Elektronen zur lnitiierung der Deflagration oder Detonati on beitragen. E inige Materialien, z.B. Halbleiter vom p-Typ, können Exo-Elektronen absorbieren und bei Verwendung al s Additive die Stoßode r Re ibempfindlic hkeit von T reibstoffen ode r Sprengstoffen reduzieren. Es wurde gefund en, daß e!urch Zusatz von 1% Siliciumpu lver vom p-Ty p e! ie Schl agempfine!lichkeit von Treibstoffe n, die Amm oniumperchlorat in einer Po lybutadi en-M atri x enthalten, abnimmt; die Schl agempfindlichkeit wird aber nicht vermindert bei HMX-, RDX-une! PETN-Pulvern. SummaryMany material s, upon fracturing, emit electrons (exo-electrons) by a process call ed fracto-emi ss ion. For a substance or mi xture th at can defl ag rate or e!etonate upon impact or fri cti on, these exo-electron s may contribute to the initi ati on of defl agrati on or detonation .Some materi als, such as p-type semi conducto rs, can abso rb exoelectrons ane! , as used as additives, ca n redu ce the impact or friction sensitivity of propellants or ex plosives. It was fo und th at the additi on of 1% p-type silicon powder d id decrease th e impact sensiti vity of a propell ant consistin g of amm o nium perchlorate in a po lybutadi ene matri x, but did not reduce the impact sensitivity of powde red cyclotetramethyle nete tranitramin e (HMX), cycl otrim eth ylenetrinitra min e (RDX), and pentaerythr itol trinitrate (PETN) .

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Emission of High Energy Electrons during Mechanical Treatment of Alkali Halides

Cited by 29 publications

References 1 publication

Clear Signature of the (2 × 1) Reconstruction of Calcite (101̅4)

Clear Signature of the (2 × 1) Reconstruction of Calcite (101̅4)

Electrostatic Processing of Mineral Salt Mixtures: The Selectively‐stimulated Contact Charging of Kieserite (MgSO₄ · H₂O). An Interpretation

Impact Sensitivity Reduction Via Exo‐Electron Control

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Emission of High Energy Electrons during Mechanical Treatment of Alkali Halides

Cited by 29 publications

References 1 publication

Clear Signature of the (2 × 1) Reconstruction of Calcite (101̅4)

Clear Signature of the (2 × 1) Reconstruction of Calcite (101̅4)

Electrostatic Processing of Mineral Salt Mixtures: The Selectively‐stimulated Contact Charging of Kieserite (MgSO4 · H2O). An Interpretation

Impact Sensitivity Reduction Via Exo‐Electron Control

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Electrostatic Processing of Mineral Salt Mixtures: The Selectively‐stimulated Contact Charging of Kieserite (MgSO₄ · H₂O). An Interpretation