81 research outputs found
N_pN_n dependence of empirical formula for the lowest excitation energy of the 2^+ states in even-even nuclei
We examine the effects of the additional term of the type on the recently proposed empirical formula for the lowest excitation
energy of the states in even-even nuclei. This study is motivated by the
fact that this term carries the favorable dependence of the valence nucleon
numbers dictated by the scheme. We show explicitly that there is not
any improvement in reproducing by including the extra
term. However, our study also reveals that the excitation energies
, when calculated by the term alone (with the mass number
dependent term), are quite comparable to those calculated by the original
empirical formula.Comment: 14 pages, 5 figure
Intense pulsed helium droplet beams
Pulsed (30 - 100 microseconds) nozzle beams have been used to generate helium
droplets ( = 10^4-10^5). The dependence of the beam intensity and the mean
droplet size on the source stagnation pressure and temperature are studied via
mass spectroscopy and laser induced fluorescence of embedded phthalocyanine
molecules. In comparison to a cw beam the pulsed source for the same pressure
and temperature has a factor of 100 higher flux and the droplet sizes are an
order of a magnitude larger.Comment: Accepted by Review of Scientific Instrument
Findings of the WMT'22 Shared Task on Large-Scale Machine Translation Evaluation for African Languages
We present the results of the WMT'22 Shared Task on Large-Scale Machine Translation Evaluation for African Languages. The shared task included both a data and a systems track, along with additional innovations, such as a focus on African languages and extensive human evaluation of submitted systems. We received 14 system submissions from 8 teams, as well as 6 data track contributions. We report a large progress in the quality of translation for African languages since the last iteration of this shared task: there is an increase of about 7.5 BLEU points across 72 language pairs, and the average BLEU scores went from 15.09 to 22.60
Therapeutic targets and microenvironment in sequential biopsies of classical Hodgkin lymphoma at diagnosis and relapse
Classical Hodgkin lymphoma is dominated by the non-neoplastic microenvironment, while the neoplastic Hodgkin-Reed-Sternberg cells compose only a minority of cells in the lymphoma tissue. Both the Hodgkin-Reed-Sternberg cells due to their expression of CD30 and PD-L1 and the microenvironment with abundant T cells and expression of PD1 are specifically targeted by new treatment concepts. We aimed to understand the dynamics of therapeutic targets in patients treated with conventional chemotherapy. We analyzed sequential biopsy specimens obtained at diagnosis and at relapse from the same patient for morphology, immunophenotype, and microenvironmental components. The morphological subtype changed between primary and relapse biopsy in 20% of cases. The immunophenotype was stable with respect to CD30, CD3, and LMP1 but variable with respect to CD15 and CD20 expression. Gene expression revealed 8 upregulated and 20 downregulated genes at relapse (p <= 0.05) with a consistent logarithmic fold change direction in at least 75% of all cases. For PD1, we found discrepant results between gene expression analysis (decrease at relapse) and number of PD1-positive cells assessed by immunohistochemistry (unchanged at relapse). PD-L1 in the neoplastic cells appeared unchanged between primary diagnosis and relapse. The expression of the therapeutic targets CD30, PD1, and PD-L1 can reliably be assessed in tumor specimen at first diagnosis and is unchanged under conventional chemotherapy
Allogeneic hematopoietic stem cell transplantation in China: where we are and where to go
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective and sometimes the only curative therapy for patients with certain hematological diseases. Allo-HSCT has been practiced in China for approximately 30 years, and great improvements have been made within the past decade, particularly in fields such as the haploidentical HSCT system, strategies to overcome relapse and GVHD, and modified HSCT for elderly patients. This review will describe the current situation and provide a prospective of these unique aspects of Allo-HSCT in China
Core Level Photelectron and X-Ray Absorption Spectroscopy of Free Argon Clusters: Size-Dependent Energy Shifts and Determination of Surface Atom Coordination
Core level photoelectron and x-ray absorption spectra for free argon clusters from 〈N〉≈5 to 〈N〉≈4000 are presented. Spectral features originating from surface and bulk sites of the clusters are identified. These are seen to shift with cluster size. From the development of the spectra from the isolated atom to the largest clusters, information about both the size-dependent cluster-specific electronic structure and that of the “infinite” solid is obtained. Using a simple model for the core level binding energy shifts, effective surface coordination numbers are derived. These range from 5.3 for 〈N〉≈10 to 8.5 for the solid
RF Loads for Energy Recovery
Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ◦C) are discussed. Another design deals with a very high temperature (up to 800 ◦C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the microwave absorber and is not brazed to the metallic enclosure
Measurements of electron cloud density in the CERN Super Proton Synchrotron with the microwave transmission method
The electron cloud effect can pose severe performance limitations in high-energy particle accelerators as the CERN Super Proton Synchrotron (SPS). Mitigation techniques such as vacuum chamber thin film coatings with low secondary electron yields (SEY < 1.3) aim to reduce or even suppress this effect. The microwave transmission method, developed and first applied in 2003 at the SPS, measures the integrated electron cloud density over a long section of an accelerator. This paper summarizes the theory and measurement principle and describes the new SPS microwave transmission setup used to study the electron cloud mitigation of amorphous carbon coated SPS dipole vacuum chambers. Comparative results of carbon coated and bare stainless steel dipole vacuum chambers are given for the beam with nominal LHC 25 ns bunch-to-bunch spacing in the SPS and the electron cloud density is derived
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