Pyridazines Lil. Polychloro Pyrido(2,3-d)- and -(3,4-d)pyridazines

The successful synthesis of perchloroimidazo(l,2-b)pyridazine1 prompted us to investigate the possibility .of preparing chlorinated pyridopyridazines. Although both parent bicyclic systems (I, II) are not expected to be susceptible to electrophilic substitution, pyrido(2,3-d)pyridazine, when brominated, formed primarily a complex which upon pyrolysis at 170- 180° is transformed into the 3-bromo derivative2

Fine-tuning the functional properties of carbon nanotubes via the interconversion of encapsulated molecules

Tweaking the properties of carbon nanotubes is a prerequisite for their practical applications. Here we demonstrate fine-tuning the electronic properties of single-wall carbon nanotubes via filling with ferrocene molecules. The evolution of the bonding and charge transfer within the tube is demonstrated via chemical reaction of the ferrocene filler ending up as secondary inner tube. The charge transfer nature is interpreted well within density functional theory. This work gives the first direct observation of a fine-tuned continuous amphoteric doping of single-wall carbon nanotubes

Linear plasmon dispersion in single-wall carbon nanotubes and the collective excitation spectrum of graphene

We have measured a strictly linear pi-plasmon dispersion along the axis of individualized single wall carbon nanotubes, which is completely different from plasmon dispersions of graphite or bundled single wall carbon nanotubes. Comparative ab initio studies on graphene based systems allow us to reproduce the different dispersions. This suggests that individualized nanotubes provide viable experimental access to collective electronic excitations of graphene, and it validates the use of graphene to understand electronic excitations of carbon nanotubes. In particular, the calculations reveal that local field effects (LFE) cause a mixing of electronic transitions, including the 'Dirac cone', resulting in the observed linear dispersion

THE EFFECT OF ROTATIONAL GRAZING ON FLORISTIC COMPOSITION AND YIELD OF Ranunculo repentis – Alopecuretum pratensis HILLY GRASSLAND

V letih 2001 in 2002 smo ugotavljali vpliv uvedbe celoletne čredinske paše z različno popasenostjo ruše - do 4 (obravnavanje 1) in do 7 cm (obravnavanje 2) na pridelek in spremembe v rastlinski sestavi donedavnega hribovskega travnika združbe Ranunculo repentis – Alopecuretum pratensis. Eksperimentalni pašnik (0.53 ha) je bil razdeljen na šest čredink – dve obravnavanji v treh ponovitvah (naključni bloki). S pašo v posamezni čredinki je osem krav svetlolisaste pasme pričelo ob višini ruše približno 15 cm in rušo v dnevu do dveh popaslo do ciljne višine. Celoletna paša ruše do različne višine v dveh letih izvajanja poskusa ni značilno različno vplivala na skupni pridelek sušine. Število različnih rastlinskih vrst v ruši se je iz začetnih 57 do spomladi 2002 zmanjšalo pod 40, nakar je do spomladi 2003 spet naraslo in sicer na 44 (1) oziroma 45 (2). Shanonov indeks rastlinske pestrosti (H) je z uvedbo paše iz začetnih 3.16 v drugem letu upadel na 2.69 (1) oziroma na 2.72 (2). V naslednjem letu pa se je ponovno povečal na 2.87 (1) oziroma 2.91 (2).In the years 2001 and 2002 the effect of the introduction of the whole year rotational grazing with different post-grazing target sward heights (4 cm in the treatment 1, and 7 cm in the treatment 2) on the yield and changes in floristic composition of the Ranunculo repentis – Alopecuretum pratensis hilly grassland was studied. A meadow (0.53 ha) was divided into six paddocks (randomised block design - two treatments, three replications). Eight Simmental cows started grazing in paddocks at 15 cm sward height. After one or two days of grazing the target height of sward was achieved. During the two-year experiment, the whole year rotational grazing to various post-grazing target sward heights did not have a significantly different effect on the total dry matter (DM) yield. The number of different plant species in the sward, however, fell from the initial 57 to under 40 by the spring 2002, but by the spring 2003 the number rose again to 44 in the treatment 1, and to 45 in the treatment 2. Due to change in the utilisation, the Shannon diversity index (H) fell from the initial 3.16 to 2.69 in the second year (treatment 1) and to 2.72 (treatment 2). Next year it increased again to 2.87 (treatment 1) and to 2.91 (treatment 2)

Charge collection properties of irradiated depleted CMOS pixel test structures

Edge-TCT and charge collection measurements with passive test structures made in LFoundry 150 nm CMOS process on p-type substrate with initial resistivity of over 3 k$\Omega$cm are presented. Measurements were made before and after irradiation with reactor neutrons up to 2$\cdot$10$^{15}$ n$_{\mathrm{eq}}$/cm$^2$. Two sets of devices were investigated: unthinned (700 $\mu$m) with substrate biased through the implant on top and thinned (200 $\mu$m) with processed and metallised back plane. Depleted depth was estimated with Edge-TCT and collected charge was measured with $^{90}$Sr source using an external amplifier with 25 ns shaping time. Depleted depth at given bias voltage decreased with increasing neutron fluence but it was still larger than 70 $\mu$m at 250 V after the highest fluence. After irradiation much higher collected charge was measured with thinned detectors with processed back plane although the same depleted depth was observed with Edge-TCT. Most probable value of collected charge of over 5000 electrons was measured also after irradiation to 2$\cdot$10$^{15}$ n$_{\mathrm{eq}}$/cm$^2$. This is sufficient to ensure successful operation of these detectors at the outer layer of the pixel detector in the ATLAS experiment at the upgraded HL-LHC

Gain Recovery in Heavily Irradiated Low Gain Avalanche Detectors by High Temperature Annealing

Studies of annealing at temperatures up to 450$^\circ$C with LGADs irradiated with neutrons are described. It was found that the performance of LGADs irradiated with 1.5e15 n/cm$^2$ was already improved at 5 minutes of annealing at 250$^\circ$C. Isochronal annealing for 30 minutes in 50$^\circ$C steps between 300$^\circ$C and 450$^\circ$C showed that the largest beneficial effect of annealing is at around 350$^\circ$C. Another set of devices was annealed for 60 minutes at 350$^\circ$C and this annealing significantly increased V$_{\mathrm{gl}}$. The effect is equivalent to reducing the effective acceptor removal constant by a factor of $\sim$ 4. Increase of V$_{\mathrm{gl}}$ is the consequence of increased effective space charge in the gain layer caused by formation of electrically active defects or re-activation of interstitial Boron atoms

Exciton-plasmon states in nanoscale materials: breakdown of the Tamm-Dancoff approximation

Within the Tamm-Dancoff approximation ab initio approaches describe excitons as packets of electron-hole pairs propagating only forward in time. However, we show that in nanoscale materials excitons and plasmons hybridize, creating exciton--plasmon states where the electron-hole pairs oscillate back and forth in time. Then, as exemplified by the trans-azobenzene molecule and carbon nanotubes, the Tamm-Dancoff approximation yields errors as large as the accuracy claimed in ab initio calculations. Instead, we propose a general and efficient approach that avoids the Tamm--Dancoff approximation, and correctly describes excitons, plasmons and exciton-plasmon states