We present the first measurement of the ^{47}K(d,pγ)^{48}K transfer reaction, performed in inverse kinematics using a reaccelerated beam of ^{47}K. The level scheme of ^{48}K has been greatly extended, with nine new bound excited states identified and spectroscopic factors deduced. Uniquely, the ^{47}K(d,p) reaction gives access to nuclear states that are sensitive to the interaction of protons and neutrons in the widely spaced 1s and fp orbitals, respectively. Detailed comparisons with SDPF-U and SDPF-MU shell-model calculations reveal a number of discrepancies between theory and experiment. Intriguingly, a systematic overestimation of spectroscopic factors and a poor reproduction of the energies for 1^{-} states suggests that the mixing between the πs_{1/2}^{1}d_{3/2}^{4} and πs_{1/2}^{2}d_{3/2}^{3} proton configurations in ^{48}K is not correctly described using current interactions, challenging our description of light nuclei around the N=28 island of inversion.
Excited states in 20O were populated in the reaction 10Be(14C,alpha) at Florida State University (FSU). Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and gamma radiation was detected with the FSU gamma detector array. Five new states were observed below 6 MeV from the alpha-gamma and alpha-gamma-gamma coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited 1p-1h excitations across the N=Z=8 shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the p-sd shell gap as neutrons are added.
Spin and parity dependent nuclear level densities (NLDs) are obtained for configuration interaction shell model using a numerically efficient spectral distribution method. The calculations are performed for $^{24}$Na, $^{25,26,27}$Mg nuclei using full $sd$-$pf$ model space that incorporates the cross-shell excitations from $sd$ to $pf$-shell. The NLDs so obtained are then employed to determine the s-wave neutron resonance spacing (D$_0$) which is one of the crucial inputs for the predictions of astrophysical reaction rates. Though the considered nuclei are not neutron-rich, the contributions from cross-shell excitations to $pf$-shell are indispensable to explain the experimental data for D$_0$ which otherwise are significantly overestimated.
Bound states of the neutron-deficient, near-dripline nucleus $^{36}$Ca were populated in two-neutron removal from the ground state of $^{38}$Ca, a direct reaction sensitive to the single-particle configurations and couplings of the removed neutrons in the projectile wave function. Final-state exclusive cross sections for the formation of $^{36}$Ca and the corresponding longitudinal momentum distributions, both determined through the combination of particle and $γ$-ray spectroscopy, are compared to predictions combining eikonal reaction theory and shell-model two-nucleon amplitudes from the USDB, USDC, and ZBM2 effective interactions. The final-state cross-section ratio $σ(2^+_1)/σ(0^+)$ shows particular sensitivity and is approximately reproduced only with the two-nucleon amplitudes from the ZBM2 effective interaction that includes proton cross-shell excitations into the $pf$ shell. Characterizing the proton $pf$-shell occupancy locally and schematically, an increase of the $sd$-$pf$ shell gap by $250$ keV yields an improved description of this cross-section ratio and simultaneously enables a reproduction of the $B(E2;0^+_1\to2^+_1)$ excitation strength of $^{36}$Ca. This highlight
The cross-shell excited states of $^{34}$Si have been investigated via $β$-decays of the $4^-$ ground state and the $1^+$ isomeric state of $^{34}$Al. Since the valence protons and valence neutrons occupy different major shells in the ground state as well as the intruder $1^+$ isomeric state of $^{34}$Al, intruder levels of $^{34}$Si are populated via allowed $β$ decays. Spin assignments to such intruder levels of $^{34}$Si were established through $γ$-$γ$ angular correlation analysis for the negative parity states with dominant configurations $(νd_{3/2})^{-1} \otimes (νf_{7/2})^{1}$ as well as the positive parity states with dominant configurations $(νsd)^{-2} \otimes (νf_{7/2}p_{3/2})^2$. The configurations of such intruder states play crucial roles in our understanding of the $N=20$ shell gap evolution. A configuration interaction model derived from the FSU Hamiltonian was utilized in order to interpret the intruder states in $^{34}$Si. Shell model interaction derived from a more fundamental theory with the Valence Space In Medium Similarity Renormalization Group (VS-IMSRG) method was also employed to interpret the structure of $^{34}$Si.
The low-lying structure of $^{15}$C has been investigated via the neutron-removal $^{16}$C$(d,t)$ reaction. Along with bound neutron sd-shell hole states, unbound p-shell hole states have been firmly confirmed. The excitation energies and the deduced spectroscopic factors of the cross-shell states are an important measure of the $[(p)^{-1}(sd)^{2}]$ neutron configurations in $^{15}$C. Our results show a very good agreement with shell-model calculations using the SFO-tls interaction for $^{15}$C. However, a modification of the $p$-$sd$ and $sd$-$sd$ monopole terms was applied in order to reproduce the $N=9$ isotone $^{17}$O. In addition, the excitation energies and spectroscopic factors have been compared to the first calculations of $^{15}$C with the $ab~ initio$ self-consistent Green's function method employing the NNLO$_{sat}$ interaction. The results show the sensitivity to the size of the $N=8$ shell gap and highlight the need of going beyond the current truncation scheme in the theory.
Non-thermal plasma(NTP)-assisted CO₂ conversion enables molecular activation under mild conditions, yet its efficiency is still constrained by the coupled limitations of active-species transport, local discharge distribution, and interfacial utilization. Current designs of plasma catalysts mainly focus on active sites, defect engineering, and metal-support interactions, whereas the role of catalyst geometry in regulating the coupling between discharge activation and mass transport remains insufficiently explored. Inspired by the generalized Murray's law for geometric transport optimization and hierarchical scale matching, this work considers the internal cavity, shell diffusion pathway, and mesoporous channels as coupled multiscale transport units, and constructs hierarchical hollow Cu/TiO₂ catalysts with tunable cavity-shell ratios. Thin, Thick, and Solid samples were employed as comparative catalysts to systematically investigate the influence of cavity-shell matching on dielectric barrier discharge (DBD)-assisted reverse water-gas shift (RWGS) reaction performance. The results show that the Thin sample, which approaches the Murray-like cavity-shell matching trend, exhibits the best CO₂ conversion performance, achieving a CO₂ conversion of 37.11%, higher than those of Thick and Solid samples, 31.77% and 22.06%, respectively, while maintaining stability and energy utilization. Structural characterization, optical emission spectroscopy (OES), and COMSOL simulations reveal that the Thin configuration shortens the cross-shell transport pathway, enhances the local electric field and electron density, and promotes the near-surface enrichment of vibrationally excited CO₂ species. Complementary H₂ temperature-programmed desorption (H₂-TPD) and hydrogen evolution reaction (HER)-assisted measurements further reveal a broader distribution of accessible hydrogen-related adsorption states and more favorable interfacial charge transfer over the Thin sample. This study demonstrates that Murray-inspired hollow-shell structures can establish effective coupling among geometric transport matching, local discharge activation, and interfacial reaction utilization.
Like electrons in atoms, protons and neutrons in nuclei occupy orbitals in a shell structure with energy gaps at magic numbers. Radioactive-beam experiments revealed the disappearance of magic numbers in some neutron-rich isotopes. In these nuclei, configurations involving particles excited across the shell gap gain correlation energy, becoming the ground state. Neutron-rich regions of the nuclear chart that exhibit this property are known as "Islands of Inversion". Here we present the lifetime measurement of the first 2+ states in 84Mo (N = Z) and 86Mo (N = Z + 2) revealing an unexpected sharp structural change between them defining the edge of the region of deformation around 80Zr. Similarly to the neutron-rich N = 40 Island of Inversion near 64Cr where cross-shell excitations dominate, we identify this region as an Island of Inversion with symmetrical proton and neutron excitations that we term "Isospin-Symmetric Island of Inversion". Three-nucleon forces are suggested to drive Mo isotope structural changes.
Translucent egg consumption is low due to consumer acceptance and quality concerns, which is a problem that egg producers need to address. This study was performed to evaluate the reasons for the high occurrence of egg translucency in summer, as well as whether the addition of mono-dicalcium phosphate (MDCP) to the diet can relieve eggshell translucency and whether eggshell translucency is associated with the risk of bacterial invasion. A total of 72 laying hens that were 36 weeks old were randomly divided into control (CON) and MDCP groups and fed in the same environment. Results showed that the number of translucent eggs increases in July and August as the temperature and humidity increase. Compared with the CON group, in July, August, and October, the translucent egg grade (TEG) of the MDCP group was lower than that of the CON group (p < 0.05). TEG was correlated with mastoid space height (MSH), width (MSW), and area (MSA) (correlation coefficients 0.63, 0.59, and 0.68, respectively, p ≤ 0.05). There was no significant difference in the invasion rate of E. coli between translucent and non-translucent egg groups (47.2% vs. 39.33%), and translucent area and non-translucent area (13.49% vs. 15.08%). In conclusion, our results show that dietary MDCP may alleviate eggshell translucency and that eggshell translucency would not increase the probability of E. coli cross-shell penetration rate.
Results from the gamma-ray spectroscopy of {47,48}Ar exemplifying new limits of sensitivity for characterizing neutron-rich nuclei at energies around the Coulomb barrier are presented. The present results, along with interacting shell model calculations, highlight the role of cross-shell excitations and indicate the presence of a nonaxial deformation in 48Ar.
The first 2^{+} and 3^{-} states of the doubly magic nucleus ^{132}Sn are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. The ^{132}Sn ions are accelerated to an energy of 5.49  MeV/nucleon and impinged on a ^{206}Pb target. Deexciting γ rays from the low-lying excited states of the target and the projectile are recorded in coincidence with scattered particles. The reduced transition strengths are determined for the transitions 0_{g.s.}^{+}→2_{1}^{+}, 0_{g.s.}^{+}→3_{1}^{-}, and 2_{1}^{+}→3_{1}^{-} in ^{132}Sn. The results on these states provide crucial information on cross-shell configurations which are determined within large-scale shell-model and Monte Carlo shell-model calculations as well as from random-phase approximation and relativistic random-phase approximation. The locally enhanced B(E2;0_{g.s.}^{+}→2_{1}^{+}) strength is consistent with the microscopic description of the structure of the respective states within all theoretical approaches. The presented results of experiment and theory can be considered to be the first direct verification of the sphericity and double magicity of ^{132}Sn.
We report on a gamma-ray coincidence analysis using a mixed array of hyperpure germanium and cerium-doped lanthanum tri-bromide (LaBr3:Ce) scintillation detectors to study nuclear electromagnetic transition rates in the pico-to-nanosecond time regime in 33,34P and 33S following fusion-evaporation reactions between an 18O beam and an isotopically enriched 18O implanted tantalum target. Energies from decay gamma-rays associated with the reaction residues were measured in event-by-event coincidence mode, with the measured time difference information between the pairs of gamma-rays in each event also recorded using the ultra-fast coincidence timing technique. The experiment used the good full-energy peak resolution of the LaBr3:Ce detectors coupled with their excellent timing responses in order to determine the excited state lifetime associated with the lowest lying, cross-shell, Iπ=4- "intruder" state previously reported in the N=19 isotone 34P. The extracted lifetime is consistent with a mainly single-particle M2 multipolarity associated with a f7/2→d5/2 single particle transition.
We present a novel technique for studying the quenching of shell gaps in exotic isotopes. The method is based on extracting Gamow-Teller (ΔL=0, ΔS=1) transition strengths [B(GT)] to low-lying states from charge-exchange reactions at intermediate beam energies. These Gamow-Teller strengths are very sensitive to configuration mixing between cross-shell orbitals, and this technique thus provides an important complement to other tools currently used to study cross-shell mixing. This work focuses on the N=8 shell gap. We populated the ground and 2.24 MeV 0+ states in 12Be using the 12B(1+) (7Li, 7Be) reaction at 80  MeV/u in inverse kinematics. Using the ground-state B(GT) value from β-decay measurements (0.184±0.007) as a calibration, the B(GT) for the transition to the second 0+ state was determined to be 0.214±0.051. Comparing the extracted Gamow-Teller strengths with shell-model calculations, it was determined that the wave functions of the first and second 0+ states in 12Be are composed of 25±5% and 60±5% (0s)4(0p)8 configurations, respectively.
Nanocapsules with molecules threaded through the porous shells may lead to advanced cell-mimicking functional devices. Herein, we show the feasibility of synthesizing such hybrid nanostructures by using vesicle-templated polymer nanocapsules with controlled nanopores. Ship-in-a-bottle assembly inside a nanocapsule created an internal unit. An external unit was then connected to an entrapped internal unit through pre-attached linker threaded through a nanopore in the shell of the nanocapsule. Both internal and external units are larger than the pore size and cannot cross the shell, producing a rotaxane-like structure. Successful synthesis was achieved with fairly short linkers (six and ten carbon atoms in a chain), creating an opportunity for facile synthesis of functional devices capable of cross-shell communication.
We present the nuclear matrix element for the neutrinoless double-beta decay of ^{48}Ca based on large-scale shell-model calculations including two harmonic oscillator shells (sd and pf shells). The excitation spectra of ^{48}Ca and ^{48}Ti, and the two-neutrino double-beta decay of ^{48}Ca are reproduced in good agreement to the experimental data. We find that the neutrinoless double-beta decay nuclear matrix element is enhanced by about 30% compared to pf-shell calculations. This reduces the decay lifetime by almost a factor of 2. The matrix-element increase is mostly due to pairing correlations associated with cross-shell sd-pf excitations. We also investigate possible implications for heavier neutrinoless double-beta decay candidates.
A marked difference in the nuclear charge radius was observed between the I^{π}=3^{+} ground state and the I^{π}=0^{+} isomer of ^{38}K and is qualitatively explained using an intuitive picture of proton-neutron pairing. In a high-precision measurement of the isomer shift using bunched-beam collinear laser spectroscopy at CERN-ISOLDE, a change in the mean-square charge radius of ⟨r_{c}^{2}⟩(^{38}K^{m})-⟨r_{c}^{2}⟩(^{38}K^{g})=0.100(6)  fm^{2} was obtained. This is an order of magnitude more accurate than the result of a previous indirect measurement from which it was concluded that both long-lived states in ^{38}K have similar charge radii. Our observation leads to a substantially different understanding since the difference in charge radius is, moreover, opposite in sign to previously reported theoretical predictions. It is demonstrated that the observed isomer shift can be reproduced by large-scale shell-model calculations including proton and neutron excitations across the N,Z=20 shell gaps, confirming the significance of cross-shell correlations in the region of ^{40}Ca.
In spite of many decades of experience and huge data resources to evaluate the results of increasingly difficult and extensive acetabulum revision operations, it is not possible to obtain fully satisfactory results. This article presents the indications for use, surgical technique, and distant and intermediate-range results in the operation of replacing a loosened acetabular component of an endoprosthesis with accompanying extensive cavitary or segmental floor defects. A retrospective evaluation was performed on 65 hips in 55 patients, including bila-teral procedures in 8 women and 2 men, operated on between 1994 and 2012. The mean age of the patients at the time of surgery was 66 +/- 16 years. The average duration of follow-up was 9 years and 3 months. Clinical results at 36 months from the surgery showed that the Harris Hip Score had increased by a mean of 47.2 HHS points and the WOMAC index had increased by 37.7 points. 1. The use of the method described in the article in selected cases produces good and excellent results, especially with the use of double reinforcement. 2. A basic prerequisite for the use of the basket is stable support for at least 3 arms of the basket on the acetabular bone reinforcement ring and good protection of grafts in the bone stock with sufficient biological capacity.
1. The lethal dose of dichloroethylsulfide (distilled from a German yellow cross shell), when injected intravenously into rabbits is from 0.005 to 0.01 gm. per kilo. 2. Rabbits dying within 24 hours showed extensive hemorrhages, and edema of the lungs. 3. Severe lesions of the intestinal tract were present in about one-third of the rabbits. 4. Dichloroethylsulfide injected intravenously is specifically poisonous for the hematopoietic tissues. Severe lesions are caused in the bone marrow, and the number of circulating leucocytes is markedly deminished. In animals surviving the injection regeneration occurs. The granular cells of the bone marrow seem to be more sensitive than the lymphoid cells and the erythrocytes. 5. The effect upon the blood and hematopoietic tissues is not due to the admixture of nitrobenzene or chlorobenzene in the shell filling. Injection of these substances in animals in amounts many times greater than the total dose of dichloroethylsulfide used produced no changes in the blood picture, and the subsequent injection of dichloroethylsulfide free from these solvents produced a typical reaction.
An opacity model that incorporates improved treatments of both plasma screening and configuration interaction (CI) effects is proposed, and a 25-30% enhancement on the iron L-shell opacity is predicted at solar interior temperatures. It is originated from the plasma screening induced 14-17% enhancement on the photoionization cross sections and the CI induced 10-20% enhancement on photoexcitation and photoionization cross sections for open L-shell ions. These explain the long-standing discrepancy between theoretical and experimental iron opacity [Nature 517, 56], and the relatively weaker enhancements on chromium and nickel opacity [Phys. Rev. Lett. 122, 235001] due to the sensitivity of these effects to the different L-shell electron population and plasma temperature/density. This letter provides the systematic interpretation of L-shell opacity measurements at solar interior temperatures, and advances the accurate simulation of opacity and radiative transport in high-energy-density plasma.
Recent measurements of the $t\bar{t}$ cross section, performed both inclusively and differentially by the ATLAS and CMS Collaborations, are reported. In particular, off-shell effects are probed in the $pp\to W^+bW^-\bar{b}$ and $pp\to e^\pmμ^\mp +b\bar{b}$ processes, and modelling aspects of the POWHEG bb4$\ell$ Monte Carlo generator are discussed. Cross section and properties measurements are also performed at the threshold: we review an indirect extraction of the top quark Yukawa coupling, as well as the recent observations by both experiments of an excess of events near the top pair production threshold that is consistent with the formation of quasi-bound states.