An Automatic Field Optical Meteorological Station Automatic

An optoelectronic measuring complex is used for prompt measurements of the atmospheric transparency to wavelengths of 0.35–1.03 m and the meteorological optical range of 0.1–300 km under various weather conditions with a relative error of no more than 15%.     

Parameter selection and efficient data processing methods in a variable-base antenna testing range

Translated from Izmeritel'naya Tekhnika, No. 2, pp. 47–49, February, 1991.     

Dihydrogen Catalysis: A Remarkable Avenue in the Reactivity of Molecular Hydrogen

Molecular hydrogen is the simplest and most abundant compound in the universe and is involved in numerous industrial chemical processes. In conventional chemistry, dihydrogen typically plays the role of a reductant and a reagent for homogeneous and heterogeneous hydrogenation processes such as the industrial and enzymatic ammonia formation, reduction of metallic ores and hydrogenation of unsaturated fats and oils. However, there are also processes in which molecular hydrogen participates as promoter, and even as catalyst. The catalytic role of the dihydrogen in free-valence migration in irradiated polymers and the interstellar isomerization of the formyl cation (protonated carbon monoxide) are well-documented examples of such processes. Recently, this issue has received new attention. Dihydrogen has been shown to play the role of a dehydrogenation catalyst (involving particularly metallocomplexes and inorganic materials), a relay (pass-on) transfer molecular agent and a transporter of protons.

This review article, combined with original results, is focused on the mechanisms of the chemical processes where dihydrogen demonstrates catalytic behavior. We will call these processes (with somewhat broader meaning of the term) “dihydrogen catalysis” (DHC) which also includes the reactions mediated by transition metal dihydrides. Dihydrides are tentatively considered as pre-activated dihydrogen, coordinated to a metal center or implanted into a solid surface/support.

DHC reactions are classified into five major reaction types: (i) dihydrogen-assisted relay transport of H-atoms (H2-RT); (ii) dihydrogen-assisted stepwise relay transport of H-atoms or of a free valence (sH2-RT); (iii) dihydrogen-assisted proton transport (H2-PT); (iv) dihydrogen-assisted dehydrogenation (H2-DeH); and (v) pre-activated dehydrogenation (PA-DeH). The classification of these mechanisms is based on a detailed analysis of numerous potential energy surfaces studied by DFT and ab initio methods in conjunction with available experimental data. The H2-RT, H2-DeH, and PA-DeH processes occur via cyclic transition states. The relay H2-RT transport involves the H-H-H triad linked to both H-donor and H-acceptor centers, whereas the transition state ring in the H2-DeH dehydrogenation processes involves a H-H-H-H tetrad with the dihydrogen catalyst located in the middle. The H2-PT mechanism provides the transport of a proton mediated by dihydrogen combined in a triangular (H₃⁺)-carrier unit.

There are also practically important processes stimulated by dihydrogen such as the hydrogen spillover and hydrogen build-up in electronics, in which the catalytic role of dihydrogen is ambiguous, either because of the uncertainties in mechanisms, or prevailing traditional views. Some examples are briefly discussed in the framework of the concept of dihydrogen catalysis, some being provided with theoretical support (in part calculated by us), and others being merely hypothesized to provide suggestions to an interested reader.     

Can Western science provide a foundation for acupuncture?

Acupuncture and other complementary medical modalities that involve holistic principles challenge the dominant biomedical paradigm of mechanical reductionism and therefore are considered unconventional or alternative. This keynote presentation will review three different hypotheses of acupuncture, two of which lie within the dominant scientific paradigm, and a third that is built upon frontier ideas at the edge of the new science of bioelectromagnetics. The Zhang-Popp hypothesis, based on endogenous electromagnetic fields of the body, is capable of accommodating many puzzling features of acupuncture. In order to embody the latter, it appears that a new paradigm for the life sciences is needed to address the wholeness and integrity of the organism. Nonetheless, I believe that there are serious limitations in attempting to embrace the indigenous knowledge system of the East, one of the oldest systems of empirical knowledge, by a 300-year-old science of the West, because of their vast differences in biophilosophies and cultural orientations. All knowledge systems, East or West, are context-dependent; none can represent true objectivity. Despite this pluralistic view, working toward a unity of Eastern and Western thought may lead to a more universal understanding of acupuncture in the future.