Superfluidity in a Doped Helium Droplet

Path Integral Monte Carlo calculations of the superfluid density throughout ^4He droplets doped with linear impurities (HCN)_n are presented. After deriving a local estimator for the superfluid density distribution, we find a decreased superfluid response in the first solvation layer. This effective normal fluid exhibits temperature dependence similar to that of a two-dimensional helium system.Comment: 4 pages, 6 figure

An audio FIR-DAC in a BCD process for high power Class-D amplifiers

A 322 coefficient semi-digital FIR-DAC using a 1-bit PWM input signal was designed and implemented in a high voltage, audio power bipolar CMOS DMOS (BCD) process. This facilitates digital input signals for an analog class-D amplifier in BCD. The FIR-DAC performance depends on the ISI-resistant nature of this PWM-signal. An impulse response with only positive coefficients was chosen, because of its resistance to deadzone and mismatch. With a DAC current of 0.5 mA, the dynamic range is 111 dB (A-weighted), with SINAD = 103 dB (A-weighted). The current consumption is 1mA for the analog part and 4.8 mA for the digital part. The power consumption is 29 mW at V/sub dd/ = 5 V and the chip area is 2 mm/sup 2/ including the reference diode that can be shared by more channels

Entrance Channel X-HF (X=Cl, Br, and I) Complexes studied by High-Resolution Infrared Laser Spectroscopy in Helium Nanodroplets

Rotationally resolved infrared spectra are reported for halogen atom - HF free radical complexes formed in helium nanodroplets. An effusive pyrolysis source is used to dope helium droplets with Cl, Br and I atoms, formed by thermal dissociation of Cl$_2$, Br$_2$ and I$_2$. A single hydrogen fluoride molecule is then added to the droplets, resulting in the formation of the X-HF complexes of interest. Analysis of the resulting spectra confirms that the observed species have $^2\Pi_{3/2}$ ground electronic states, consistent with the linear hydrogen bound structures predicted from theory. Stark spectra are also reported for these species, from which the permanent electric dipole moments are determined.Comment: 41 pages, 16 figures, 5 table

Table of Contents

Table of contents for Volume 10, Issue 3 of the Linfield Magazin

A superfluid hydrodynamic model for the enhanced moments of inertia of molecules in liquid 4He

We present a superfluid hydrodynamic model for the increase in moment of inertia, $\Delta I$, of molecules rotating in liquid $^4$He. The static inhomogeneous He density around each molecule (calculated using the Orsay-Paris liquid $^4$He density functional) is assumed to adiabatically follow the rotation of the molecule. We find that the $\Delta I$ values created by the viscousless and irrotational flow are in good agreement with the observed increases for several molecules [ OCS, (HCN)$_2$, HCCCN, and HCCCH$_3$ ]. For HCN and HCCH, our model substantially overestimates $\Delta I$. This is likely to result from a (partial) breakdown of the adiabatic following approximation.Comment: 4 pages, 1 eps figure, corrected version of published paper. Erratum has been submitted for change

A high-resolution infrared spectroscopic investigation of the halogen atom-HCN entrance channel complexes solvated in superfluid helium droplets

Rotationally resolved infrared spectra are reported for the X-HCN (X = Cl, Br, I) binary complexes solvated in helium nanodroplets. These results are directly compared with that obtained previously for the corresponding X-HF complexes [J. M. Merritt, J. K\"upper, and R. E. Miller, PCCP, 7, 67 (2005)]. For bromine and iodine atoms complexed with HCN, two linear structures are observed and assigned to the $^{2}\Sigma_{1/2}$ and $^{2}\Pi_{3/2}$ ground electronic states of the nitrogen and hydrogen bound geometries, respectively. Experiments for HCN + chlorine atoms give rise to only a single band which is attributed to the nitrogen bound isomer. That the hydrogen bound isomer is not stabilized is rationalized in terms of a lowering of the isomerization barrier by spin-orbit coupling. Theoretical calculations with and without spin-orbit coupling have also been performed and are compared with our experimental results. The possibility of stabilizing high-energy structures containing multiple radicals is discussed, motivated by preliminary spectroscopic evidence for the di-radical Br-HCCCN-Br complex. Spectra for the corresponding molecular halogen HCN-X$_{2}$ complexes are also presented.Comment: 20 pages, 15 figures, 6 tables, RevTe

Personalised app-based relapse prevention of depressive and anxiety disorders in remitted adolescents and young adults:a protocol of the StayFine RCT

INTRODUCTION: Youth in remission of depression or anxiety have high risks of relapse. Relapse prevention interventions may prevent chronicity. Aim of the study is therefore to (1) examine efficacy of the personalised StayFine app for remitted youth and (2) identify high-risk groups for relapse and resilience. METHOD AND ANALYSIS: In this Dutch single-blind parallel-group randomised controlled trial, efficacy of app-based monitoring combined with guided app-based personalised StayFine intervention modules is assessed compared with monitoring only. In both conditions, care as usual is allowed. StayFine modules plus monitoring is hypothesised to be superior to monitoring only in preventing relapse over 36 months. Participants (N=254) are 13–21 years and in remission of depression or anxiety for >2 months. Randomisation (1:1) is stratified by previous treatment (no treatment vs treatment) and previous episodes (1, 2 or >3 episodes). Assessments include diagnostic interviews, online questionnaires and monitoring (ecological momentary assessment with optional wearable) after 0, 4, 12, 24 and 36 months. The StayFine modules are guided by certified experts by experience and based on preventive cognitive therapy and ingredients of cognitive behavioural therapy. Personalisation is based on shared decision-making informed by baseline assessments and individual symptom networks. Time to relapse (primary outcome) is assessed by the Kiddie Schedule for Affective Disorders and Schizophrenia-lifetime version diagnostic interview. Intention-to-treat survival analyses will be used to examine the data. Secondary outcomes are symptoms of depression and anxiety, number and duration of relapses, global functioning, and quality of life. Mediators and moderators will be explored. Exploratory endpoints are monitoring and wearable outcomes. ETHICS, FUNDING AND DISSEMINATION: The study was approved by METC Utrecht and is funded by the Netherlands Organisation for Health Research and Development (636310007). Results will be submitted to peer-reviewed scientific journals and presented at (inter)national conferences. TRIAL REGISTRATION NUMBER: NCT05551468; NL8237