Organometallic polymers: An infinite organoplatinum chain in the solid state formed by (C CH center dot center dot center dot ClPt)hydrogen bonds

The new platinum complex [PtCl[C6H2(CH(2)NMe(2))(2) -2,6-(C=CH)-4)] exhibits a polymeric linear -C=CH ... ClPt-hydrogen-bonded structure in the solid state.

The Bonds of Brotherhood: New Evidence of Sino-North Korean Exchanges, 1950-1954

Drawing on recently declassified documents from the archive of the Foreign Ministry of the People’s Republic of China (PRC), this article looks at China’s relationship with North Korea during and immediately after the Korean War. Although previous scholarship has touched on PRC–North Korean military ties during the war, this article is the first in-depth analysis of issues that are less well understood, notably China’s efforts to cope with a huge influx of refugees from North Korea, the PRC’s economic assistance during the war and in the early postwar reconstruction, and Chinese educational and ideological support for North Korean professionals and party cadres. The article shows that the extensive military coordination between Beijing and Pyongyang was only one way in which the war brought North Korea and the PRC into a closer relationship

Force-induced activation of covalent bonds in mechanoresponsive polymeric materials

Mechanochemical transduction enables an extraordinary range of physiological processes such as the sense of touch, hearing, balance, muscle contraction, and the growth and remodelling of tissue and
bone1–6. Although biology is replete with materials systems that actively and functionally respond to mechanical stimuli, the default mechanochemical reaction of bulk polymers to large external stress is the unselective scission of covalent bonds, resulting in damage or failure7. An alternative to this degradation process is the rational molecular design of synthetic materials such that mechanical stress
favourably altersmaterial properties. A few mechanosensitive polymers with this property have been developed8–14; but their active response is mediated through non-covalent processes, which may
limit the extent to which properties can be modified and the longterm stability in structural materials. Previously, we have shown with dissolved polymer strands incorporating mechanically sensitive chemical groups—so-called mechanophores—that the directional nature of mechanical forces can selectively break and re-form covalent bonds15,16. We now demonstrate that such forceinduced covalent-bond activation can also be realized with mechanophore-linked elastomeric and glassy polymers, by using a mechanophore that changes colour as it undergoes a reversible electrocyclic ring-opening reaction under tensile stress and thus allows us to directly and locally visualize the mechanochemical reaction. We find that pronounced changes in colour and fluorescence emerge with the accumulation of plastic deformation, indicating that in these polymeric materials the transduction of mechanical force into the ring-opening reaction is an activated process. We anticipate that force activation of covalent bonds can serve as a general strategy for the development of new mechanophore building blocks that impart polymeric materials with desirable functionalities ranging from damage sensing to fully regenerative self-healing.

The failure of generalized gradient approximations (GGAs) and meta-GGAs for the two-center three-electron bonds in He-2(+), (H2O)(2)(+), and (NH3)(2)(+)

The radical cations He-2(+) (H2O)(2)(+), and (NH3)(2)(+) with two-center three-electron A-A bonds are investigated at the configuration interaction (CI), accurate Kohn-Sham (KS), generalized gradient approximation (GGA), and meta-GGA levels. Assessment of seven different GGA and six meta-GGA methods shows that the A(2)(+) systems remain a difficult case for density functional theory (DFT). All methods tested consistently overestimate the stability of A(2)(+): the corresponding D-e errors decrease for more diffuse valence densities in the series He-2(+) > (H2O)(2)(+) > (NH3)(2)(+). Upon comparison to the energy terms of the accurate Kohn-Sham solutions, the approximate exchange functionals are found to be responsible for the errors of GGA-type methods, which characteristically overestimate the exchange in A(2)(+). These so-called exchange functionals implicitly use localized holes. Such localized holes do occur if there is left-right correlation, i.e., the exchange functionals then also describe nondynamical correlation. However, in the hemibonded A(2)(+) systems the typical molecular (left-right, nondynamical) correlation of the two-electron pair bond is absent. The nondynamical correlation built into the exchange functionals is then spurious and yields too low energies.

Surface energy and surface proton order of the ice Ih basal and prism surfaces

Density-functional theory (DFT) is used to examine the basal and prism surfaces of ice Ih. Similar surface energies are obtained for the two surfaces; however, in each case a strong dependence of the surface energy on surface proton order is identified. This dependence, which can be as much as 50% of the absolute surface energy, is significantly larger than the bulk dependence (< 1%) on proton order, suggesting that the thermodynamic ground state of the ice surface will remain proton ordered well above the bulk order-disorder temperature of about 72 K. On the basal surface this suggestion is supported by Monte Carlo simulations with an empirical potential and solution of a 2D Ising model with nearest neighbor interactions taken from DFT. Order parameters that define the surface energy of each surface in terms of nearest neighbor interactions between dangling OH bonds (those which point out of the surface into vacuum) have been identified and are discussed. Overall, these results suggest that proton order-disorder effects have a profound impact on the stability of ice surfaces and will most likely have an effect on ice surface reactivity as well as ice crystal growth and morphology. S Supplementary data are available from stacks.iop.org/JPhysCM/22/074209/mmedia

On thin ice: surface order and disorder during pre-melting

The effect of temperature on the structure of the ice Ih (0001) surface is considered through a series of molecular dynamics simulations on an ice slab. At relatively low temperatures (200K) a small fraction of surface self-interstitials (i.e. admolecules) appear that are formed exclusively from molecules leaving the outermost bilayer. At higher temperatures (ca. 250 K), vacancies start to appear in the inner part of the outermost bilayer exposing the underlying bilayer and providing sites with a high concentration of the dangling hydrogen bonds. Around 250-260 K aggregates of molecules formed on top of the outermost bilayer from self-interstitials become more mobile and have diffusivities approaching that of liquid water. At similar to 270-280 K the inner bilayer of one surface noticeably destructures and it appears that at above 285 K both surfaces are melting. The observed disparity in the onset of melting between the two sides of the slab is rationalised by considering the relationship between surface energy and the spatial distribution of protons at the surface; thermodynamic stability is conferred on the surface by maximising separations between dangling protons at the crystal exterior. Local hotspots associated with a high dangling proton density are suggested to be susceptible to pre-melting and may be more efficient at trapping species at the external surface than regions with low concentrations of protons thus potentially helping ice particles to catalyse reactions. A preliminary conclusion of this work is that only about 10-20 K below the melting temperature of the particular water potential employed is major disruption of the crystalline lattice noted which could be interpreted as being "liquid", the thickness of this film being about a nanometre.

Orange Zinc Germanate with Metallic Ge-Ge Bonds as a Chromophore-Like Center for Visible-Light-Driven Water Splitting

The efficiency of solar-energy-conversion devices depends on the absorption region and intensity of the photon collectors. Organic chromophores, which have been widely stabilized on inorganic semiconductors for light trapping, are limited by the interface between the chromophore and semiconductor. Herein we report a novel orange zinc germanate (Zn-Ge-O) with a chromophore-like structure, by which the absorption region can be dramatically expanded. Structural characterizations and theoretical calculations together reveal that the origin of visible-light response can be attributed to the unusual metallic Ge-Ge bonds which act in a similar way to organic chromophores. Benefiting from the enhanced light harvest, the orange Zn-Ge-O demonstrates superior capacity for solar-driven hydrogen production.

Shear Strength and Durability Testing of Adhesive Bonds in Cross-Laminated Timber

The paper addresses the quality of the interface and edge bonded joints in layers of cross-laminated timber (CLT) panels. The shear performance was studied to assess the suitability of two different adhesives, Polyurethane (PUR) and Phenol-Resorcinol-Formaldehyde (PRF), and to determine the optimum clamping pressure. Since there is no established testing procedure to determine the shear strength of the surface bonds between layers in a CLT panel, block shear tests of specimens in two different configurations were carried out, and further shear tests of edge bonded specimen in two configurations were performed. Delamination tests were performed on samples which were subjected to accelerated aging to assess the durability of bonds in severe environmental conditions. Both tested adhesives produced boards with shear strength values within the edge bonding requirements of prEN 16351 for all manufacturing pressures. While the PUR specimens had higher shear strength values, the PRF specimens demonstrated superior durability characteristics in the delamination tests. It seems that the test protocol introduced in this study for crosslam bonded specimens, cut from a CLT panel, and placed in the shearing tool horizontally, accurately reflects the shearing strength of glue lines in CLT.

Banco BPI and the reimbursement of contingent convertible subordinated bonds (CoCos)

This case study focuses on the BPI’s recapitalization plan, its causes and the reasons for the early reimbursement of CoCos in June 2014. The need for a capital intervention and the subsequent subscription agreement with the Portuguese Government of €1 500 million Core Tier 1 instruments were the result of a temporary capital buffer for sovereign debt exposures imposed by the European Banking Authority. The capital increase, the positive earnings in 2012 and 2013, the improvements in the sovereign debt crisis, the implementation of Basel III, in addition to the public exchange offer and the conversion of deferred tax assets into tax credits are the main factors for concluding the entire recapitalization operation three years before the deadline.

Cross sectional default probabilities in european corporate bonds

This study attempts to identify basis-trading opportunities in the European banking sector by comparing two different measures for the market’s assessment of risk: market-observed CDS spreads and model-implied Z-spreads. Using a sample of 10 banks, over a period of 3 years following the European banking crisis, it can be concluded that there were arbitrage opportunities in the sector, as evidenced by the derived negative bases.

Buddy films and gender identity : representing the bonds of masculinity /

The study examines the buddy film genre and the representation of masculinity in relation to the homosocial and the homoerotic. As a genre, the buddy films focus on male relationships, thematically seeking to mediate the boundaries surrounding the homosocial continuum and the intimacy and eroticism implicit in male bonding. Theories of genre, gender and identity are used to analyze the construction of masculine identity within the films. By providing a qualitative analysis of films from the 1960s to contemporary times, the research establishes a relationship between social changes, attitudes toward men and depictions of men. The buddy films adapt to address changes in the representation of masculinity, embodied in the difference between the male couple in the films. The early films of the 1960s served as templates that deconstructed traditional representations of male identity through articulating the tension within homosocial relationships. However, in the later films this tension became a refle~ive convention, acting to undermine the eroticism onto a displaced Other. The buddy film genre highlights the tension inherent to the male masquerade. This tension is situated in the need to represent the protagonist's homosocial relationship, while disavowing the eroticism that surrounds homosocial bonding. The structure of the buddy film genre, which focuses on the exploration of masculinity and representing the bonds of homosocial intimacy, makes these films a significant site for investigating the cultural construction of masculine identities.

Bonds away : baseball mythology and the 2007 home run chase

In 2007, Barry Bonds hit his 75 6th home run, breaking Hank Aaron's all-time record for most home runs in a Major League career. While it would be expected that such an accomplishment would induce unending praise and adulationfor the new record-holder, Bonds did not receive the treatment typically reserved for a beloved baseball hero. The purpose of this thesis is to assess media representations of the 2007 home run chase in order to shed light upon the factors which led to the mixed representations which accompanied BOlTds ' assault on Aaron's record. Drawingfrom Roland Barthes ' concept of myth, this thesis proposes that Bonds was portrayed in predominantly negative ways because he was seen as failing to embody the values of baseball's mythology. Using a qualitative content analysis of three major American newspapers, this thesis examines portrayals of Bonds and how he was shown both to represent and oppose elements from baseball's mythology, such as youth, and a distant, agrarian past. Recognizing the ways in which baseball is associated with American life, the media representations of Bonds are also evaluated to discern whether he was portrayed as personifYing a distinctly American set of values. The results indicate that, in media coverage of the 2007 home run chase, Bonds was depicted as a player of many contradictions. Most commonly, Bonds' athletic ability and career achievements were contrasted with unflattering descriptions of his character, including discussions of his alleged use of performance-enhancing substances. However, some coverage portrayed Bonds as embodying baseball myth. The findings contribute to an appreciation of the importance of historical context in examining media representations. This understanding is enhanced by an analysis of a selection of articles on Mark McGwire 's record-breaking season in 1998, and careful consideration of, and comparison to, the context under which Bonds performed in 2007. Findings are also shown to support the contemporary existence of a strong American baseball mythology. That Bonds is both condemned for failing to uphold the mythology and praised for personifYing it suggests that the values seen as inherent to baseball continue to act as an American cultural benchmark.