Predicting single-layer technetium dichalcogenides (TcX2, X = S, Se) with promising applications in photovoltaics and photocatalysis

One of the least known compounds among transition metal dichalcogenides (TMDCs) is the layered triclinic technetium dichalcogenides (TcX2, X = S, Se). In this work, we systematically study the structural, mechanical, electronic, and optical properties of TcS2 and TcSe2 monolayers based on density functional theory (DFT). We find that TcS2 and TcSe2 can be easily exfoliated in a monolayer form because their formation and cleavage energy are analogous to those of other experimentally realized TMDCs monolayer. By using a hybrid DFT functional, the TcS2 and TcSe2 monolayers are calculated to be indirect semiconductors with band gaps of 1.91 and 1.69 eV, respectively. However, bilayer TcS2 exhibits direct-bandgap character, and both TcS2 and TcSe2 monolayers can be tuned from semiconductor to metal under effective tensile/compressive strains. Calculations of visible light absorption indicate that 2D TcS2 and TcSe2 generally possess better capability of harvesting sunlight compared to single-layer MoS2 and ReSe2, implying their potential as excellent light-absorbers. Most interestingly, we have discovered that the TcSe2 monolayer is an excellent photocatalyst for splitting water into hydrogen due to the perfect fit of band edge positions with respect to the water reduction and oxidation potentials. Our predictions expand the two-dimensional (2D) family of TMDCs, and the remarkable electronic/optical properties of monolayer TcS2 and TcSe2 will place them among the most promising 2D TMDCs for renewable energy application in the future.

Silva Fennica Vol. 1 (121). 1967.

Julkaistu Silva Fennica Vol. 2(1) -numeron liitteenä.

On the toxicity of some pesticides for fish [Translation from: Izv.gos.nauchno-issled.Inst.ozern.rybn.Khoz. 121, 95-96, 1977]

In the piscicide laboratory of GosNIORKh over a series of years was carried out the ichthyological evaluation of different agricultural pesticides, used both in our country and abroad. In all more than 300 different chemical substances were tested. Here, it was established that around 10% of them possessed high ichthyotoxic properties. Experiments were conducted under laboratory conditions on aquarium fish in groups, and also on representatives of different species of lake ichthyofauna. The basic criterion of evaluation of toxicity was the death of experimental fish during 120 hours. This short paper summarises the findings of this reasearch and offers a table presenting acute toxicity of pesticides for fish.

Gas-phase isothermal chromatography with short-lived technetium isotopes

In order to study the gas-phase chemical behavior of transactinides, an on-line isothermal chromatography apparatus has been developed and applied to separate short-lived technetium isotopes in the form of TcO3 from fission products. The fission products from a Cf-252 source were continuously and rapidly transported through the capillary to the isothermal chromatography apparatus using the N-2/KBr gas-jet techniques. Volatile oxide molecules were formed at the reaction zone kept at 900 degrees C since a trace amount of oxygen existed in the N-2 carrier gas. With the new developed isothermal chromatography apparatus, a selective separation of Tc from fission products was achieved. After isothermal chromatographic separation, Tc-101,Tc-103,Tc-104,Tc-105,Tc-106,Tc-107,Tc-108 were dominantly observed together with their Ru daughters in the gamma-spectrum, The chemical yields of Tc-101, and Tc-104 and Tc-105 isotopes with longer half-lives are about 55-57%, and those of Tc-103, Tc-106 and Tc-108 isotopes with shorter half-lives dropped down to 25-28%. The adsorption enthalpy of the investigated compounds on quartz surfaces was determined to be -150 +/- 5 kJ/mol by fitting the measured retention curves with a Monte Carlo model. The observed species of technetium oxide is attributed to TcO3, which is in good agreement with previous experimental results. That means our system worked properly and it can be used to investigate the gas-phase chemical behavior of transactinides.

>~（121）C核高自旋态在束γ研究和BGC晶体球性能测定

本文描述了在束γ谱学实验方法，并用这种方法研究了~（121）Cs核的高自旋态能级结构，观测到了~（121）Cs核中基于9/2~+质子空穴态上的△J = 1 的带和基于11/2~-准质子带，并在这两个带上鉴定出了四条新能级及六条新的γ跃迁。对这一结果进行了分析讨论。本文还讨论了一个小型BGO晶体球性能的测试方法，并给出了测试结果

Cyclotech - contribution to solve the Technetium shortage by using low energy medical cyclotrons

This paper presents work in progress, to develop an efficient and economic way to directly produce Technetium 99metastable (99mTc) using low-energy cyclotrons. Its importance is well established and relates with the increased global trouble in delivering 99mTc to Nuclear Medicine Departments relying on this radioisotope. Since the present delivery strategy has clearly demonstrated its intrinsic limits, our group decided to follow a distinct approach that uses the broad distribution of the low energy cyclotrons and the accessibility of Molybdenum 100 (100Mo) as the Target material. This is indeed an important issue to consider, since the system here presented, named CYCLOTECH, it is not based on the use of Highly Enriched (or even Low Enriched) Uranium 235 (235U), so entirely complying with the actual international trends and directives concerning the use of this potential highly critical material. The production technique is based on the nuclear reaction 100Mo (p,2n) 99mTc whose production yields have already been documented. Until this moment two Patent requests have already been submitted (the first at the INPI, in Portugal, and the second at the USPTO, in the USA); others are being prepared for submission on a near future. The object of the CYCLOTECH system is to present 99mTc to Nuclear Medicine radiopharmacists in a routine, reliable and efficient manner that, remaining always flexible, entirely blends with established protocols. To facilitate workflow and Radiation Protection measures, it has been developed a Target Station that can be installed on most of the existing PET cyclotrons and that will tolerate up to 400 μA of beam by allowing the beam to strike the Target material at an adequately oblique angle. The Target Station permits the remote and automatic loading and discharge of the Targets from a carriage of 10 Target bodies. On other hand, several methods of Target material deposition and Target substrates are presented. The object was to create a cost effective means of depositing and intermediate the target material thickness (25 - 100μm) with a minimum of loss on a substrate that is able to easily transport the heat associated with high beam currents. Finally, the separation techniques presented are a combination of both physical and column chemistry. The object was to extract and deliver 99mTc in the identical form now in use in radiopharmacies worldwide. In addition, the Target material is recovered and can be recycled.

Le vieux caporal : drame en cinq actes. [suivi de] Diane de lys et de camélias, ou La femme du monde légère, liée à un homme bilieux qui n'entend pas la plaisanterie : grande parodie en 3 petits tableaux. Livr. 121 / par MM. Dumanoir et d'Ennery ; par MM. Delacour et Lambert Thiboust

Collection : Théâtre contemporain illustré ; 121e et 122e livraisons

Livre des Morts de Nésyménou. Egyptien 121

Fragment 3 :Col. 1 + vignette : chapitre 28 (formule pour empêcher qu'on ne retire son coeur au défunt). La vignette montre le coeur du défunt et une divinité assise sur une maison.Col. 2 + vignette : chapitre 30B (formule pour empêcher que s'oppose le coeur du défunt). La vignette représente un scarabée.Col. 3 + vignette : chapitre 31 (formule pour repousser un crocodile venu pour enlever la magie-hékaou du défunt).Fragment 1 : la vignette montre le défunt armé d'une pique, qui devait probablement transpercer un animal néfaste.Fragment 2 :Col. 1 + vignette : chapitre 32 (formule pour repousser un crocodile venu pour enlever la magie-hékaou d'un Bienheureux de son contrôle dans la nécropole). La vignette montre deux crocodiles qui devaient être transpercés par le défunt.Col. 2 + vignette : chapitre 33 (formule pour repousser un serpent). La vignette montre le défunt transperçant un insecte (on attendrait un serpent).Col. 3 + vignette : chapitre 37 (formule pour repousser les deux amies). La vignette montre le défunt transperçant un serpent enroulé.Col. 4 + vignette (très fragmentaires) : ?