Who won the argument over plain packaging?

Government and tobacco companies recently faced off in Australia's High Court over the legality of plain packaging for cigarettes. Stephen Stern and Matthew Rimmer give their contrasting views on the arguments and implications

Complex crystallization dynamics in amorphous germanium observed with dynamic transmission electron microscopy

Crystallization of amorphous germanium (a-Ge) by laser or electron beam heating is a remarkably complex process that involves several distinct modes of crystal growth and the development of intricate microstructural patterns on the nanosecond to ten microsecond time scales. Here we use dynamic transmission electron microscopy (DTEM) to study the fast, complex crystallization dynamics with 10 nm spatial and 15 ns temporal resolution. We have obtained time-resolved real-space images of nanosecond laser-induced crystallization in a-Ge with unprecedentedly high spatial resolution. Direct visualization of the crystallization front allows for time-resolved snapshots of the initiation and roughening of the dendrites on submicrosecond time scales. This growth is followed by a rapid transition to a ledgelike growth mechanism that produces a layered microstructure on a time scale of several microseconds. This study provides insights into the mechanisms governing this complex crystallization process and is a dramatic demonstration of the power of DTEM for studying time-dependent material processes far from equilibrium.

In situ investigation of explosive crystallization in a-Ge: Experimental determination of the interface response function using dynamic transmission electron microscopy

The crystallization of amorphous semiconductors is a strongly exothermic process. Once initiated the release of latent heat can be sufficient to drive a self-sustaining crystallization front through the material in a manner that has been described as explosive. Here, we perform a quantitative in situ study of explosive crystallization in amorphous germanium using dynamic transmission electron microscopy. Direct observations of the speed of the explosive crystallization front as it evolves along a laser-imprinted temperature gradient are used to experimentally determine the complete interface response function (i.e., the temperature-dependent front propagation speed) for this process, which reaches a peak of 16 m/s. Fitting to the Frenkel-Wilson kinetic law demonstrates that the diffusivity of the material locally/immediately in advance of the explosive crystallization front is inconsistent with those of a liquid phase. This result suggests a modification to the liquid-mediated mechanism commonly used to describe this process that replaces the phase change at the leading amorphous-liquid interface with a change in bonding character (from covalent to metallic) occurring in the hot amorphous material.

School picture with Lotte Wallerstein; Rheydt, Germany.

Extreme lower right: Lotte Wallerstein

Studio portrait of Paula Wallerstein nee Molling holding her infant daughter Karoline "Line".

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Guests at Sophie Oppenheimer's 70th birthday celebration Portraits Groups

Handwritten on verso: (top l-r) Heinz Marcus, Hilde Marcus, Heinz Ascher, Else Stern, Gerhard Ascher, Hattie Wallerstein, Kurt Stern, Paula Stern, Lula Ascher and Hilde Marcus; (second row l-r) Otto Oppenheimer, Heinrich Ascher, Julius Stern, David Wallerstein, Max Marcus, Alex Goldschmidt and Ernst Oppenheimer; (third row l-r) Rose, Hans Oppenheimer, Gertrud Ascher, Oma Oppenheimer, Emma, Martha, Lene, Lucy, Hans, Lore; (front row l-r) Margot Ascher, Heinz Ascher, Golda Ascher, Edith Goldschmidt, Irma Ascher, Lotti Goldschmidt, Gretl Oppenheimer and Ilse Oppenheimer

Studio portrait of Paula Wallerstein nee Molling holding her infant daughter Karoline "Line".

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Portrait of Dr. Joseph Wallerstein; Danzig.

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Photo button portrait of unidentified couple, possibly cattle dealer Julius Herzberg and his wife Olga Herzberg née Eckermann Portraits Couples

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Portrait of Ilse Bergen on her first day of school holding the candy bag traditional for the occasion (Schultuete) Portraits Children

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Exterior of Congregation Ahavath Torah; Washington Avenue, Washington Heights, New York Synagogues; Exterior

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Exterior of Congregation Ahavath Torah; Washington Avenue, Washington Heights, New York Synagogues; Exterior

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Exterior of Congregation Ahavath Torah; Washington Avenue, Washington Heights, New York Synagogues; Exterior

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Exterior of Congregation Ahavath Torah; Washington Avenue, Washington Heights, New York Synagogues; Exterior

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