Shell Structure Effects Research Articles

Anchoring ZnIn2S4 nanosheets on cross-like FeSe2 to construct photothermal-enhanced S-scheme heterojunction for photocatalytic H2 evolution

Rational design of the morphology and heterojunction to accelerate the separation of electron-hole pairs has played an indispensable role in improving the photocatalytic hydrogen evolution. ZnIn2S4 (ZIS) has aroused considerable attention in solar-to-chemical energy conversion due to its remarkable photoelectrical properties and relatively negative energy band, whereas it still suffers from the severe photogenerated carrier recombination and catalyst aggregation. Herein, guided by density functional theory calculations, the constructed FeSe2@ZnIn2S4 (FS@ZIS) heterojunction model has a hydrogen Gibbs free energy closer to zero compared with pure ZIS and FS, which is beneficial for hydrogen adsorption and desorption on the photocatalyst surface. Therefore, a novel cross-like core–shell FS@ZIS Step-scheme (S-scheme) heterojunction was synthesized successfully by in-situ growing ZIS nanosheets on the surface of cross-like FS. The structure with cross-like core–shell morphology not only inhibits the agglomeration of ZIS to increase specific surface area, but also provides a tight interface with S-scheme heterojunction. Moreover, the S-scheme heterojunction with a tight interface can effectively separate electron-hole pairs, leaving photoinduced charges with higher potentials. Furthermore, FS@ZIS-20 possesses exceptional photothermal capabilities, enabling the conversion of optical energy from visible and near infrared light to heat, thereby further enhancing the photocatalysis reaction. As a result, the cross-like core–shell FS@ZIS S-scheme heterojunction exhibits an excellent photocatalytic hydrogen evolution rate (7.640 mmol g−1 h−1), which is 24 times higher than that of pure ZIS (0.319 mmol g−1 h−1) under visible and near infrared light. Furthermore, employing more in-depth density functional theory calculations further investigates the charge transfer pathway of the FS@ZIS S-scheme heterojunction. This work provides insights into the construction of S-scheme heterojunctions with core–shell structure and photothermal effect for photocatalytic evolution hydrogen.

Efficient photocatalytic selective oxidation of benzyl alcohol by nano-Pd/TiO2−x with synergistic effect of oxygen vacancy and shell structure

TiO2 hollow spheres, TiO2−x hollow spheres, and a series of Pd/TiO2 and Pd/TiO2−x hollow spheres with different Pd mass fractions were successfully synthesized by a template-based and NaBH4 reduction method. The as-synthesized catalysts are hollow sphere structures that provide a large number of active sites for photocatalytic reactions. The synergistic effect of Pd nanoparticles (NPs) and oxygen vacancy facilitated photogenerated charge transportation and separation. In particular, the optimized 4 wt% Pd/TiO2−x shows an excellent conversion (88.3%) for the photocatalytic selective oxidation of benzyl alcohol (BA) under visible light. In addition, it was observed that the catalyst had high stability and recyclability under the study conditions. The band structure, density of states and the charge difference distribution were calculated with density functional theory (DFT) methods to deeply reveal that the synergistic effect of oxygen vacancies and Pd NPs to enhance the photocatalytic performance. Consequently, a possible photocatalytic reaction mechanism has also been put forward based on the DFT and experimental results.

ZIF-derived sulfides with tremella-like core–shell structure for high performance supercapacitors

Metal-organic frameworks (MOFs) have emerged as promising active electrode materials in supercapacitors for its controllable porous structure and excellent physio-chemical properties. However, the poor conductivities keep it from achieving its full capacitance potential, which greatly limits its practical application. Here, a facile pathway is reported to fabricate the GO/Ni2ZnS4@NiCo2S4 composite with large specific surface area and favorable electrical conductivity. Thanks to the novel tremella-like core–shell structure and high-efficient synergistic effects among multi-components, the designed GO/Ni2ZnS4@NiCo2S4 electrode shows a high specific capacitance of 2284 F/g at 1 A/g. Furthermore, the asymmetric supercapacitor fabricated by coupling GO/Ni2ZnS4@NiCo2S4 positive electrode with biological carbon negative electrode achieves a remarkable energy density of 120 Wh kg−1 at a power density of 750 W kg−1.

Chitooligosaccharide modified pesticide-loaded polyurethane microcapsules to mitigate drought stress in wheat

To cope with global climate change and ensure food security, the development of functional pesticide carriers suitable for application on plants under drought stress is an important research direction. Herein, polyurethane microcapsules loading prothioconazole (PUMC@PRO) were synthesized using interfacial polymerization. Subsequently, chitooligosaccharide (COS) and glutaraldehyde (GA) were incorporated to prepare microcapsules with cross-linked network containing Schiff bases (PUMC-COS@PRO). Results demonstrated that the fitting degree of the release curve of PUMC-COS@PRO to the zero-order release kinetic model can reach up to 0.99. Due to the synergistic effect of the microcapsule shell and cross-linked network structure containing Schiff base (C=N), the half-life of PUMC-COS@PRO is 6.6 h in UV, which is approximately 28 times that of commercial microemulsion. After the introduction of COS with biologically activity, the EC50 can decrease significantly to as low as 1.612 μg/mL. In the growth promotion test, the PUMC-COS@PRO suspension exhibited the most growth promotion rate of 16.74 % on wheat stem length. Under simulated drought stress conditions, the growth promotion rates of the PUMC-COS@PRO suspension for wheat coleoptiles and radicles can achieve 22.46 % and 59.77 %, respectively. Therefore, this study provided a promising functionalized pesticide carrier for crops under drought stress in agricultural production.

Effect of solvation shell structure on thermopower of liquid redox pairs

AbstractDeveloping redox electrolytes with high thermopower is the key to making efficient thermogalvanic batteries for harvesting low‐grade heat. This work applies molecular dynamics simulations to predict the thermopower (i.e. thermogalvanic temperature coefficient) of the redox pairs Fe(CN)63−/Fe(CN)64− and Fe3+/Fe2+, showing excellent agreement with experimental values. We showed that of the Fe3+/Fe2+ redox pair can be increased from 1.70.4 mV/K to 3.80.5 mV/K with the increased acetone to water fraction. We discovered a significant change in the variance of solvent dipole orientation between Fe3+ and Fe2+, which can serve as a microscopic indicator for large . In mixed acetone‐water solvent, of Fe3+/Fe2+ showed a rapid increase at high acetone fractions, due to the intercalation of acetone molecules into the first solvation shell of the Fe2+ at high acetone fractions. Our discovery provides insights into how solvation shell order can be engineered to develop electrolytes with high .image

Molecularly Imprinted Polymer Nanospheres with Hydrophilic Shells for Efficient Molecular Recognition of Heterocyclic Aromatic Amines in Aqueous Solution.

Heterocyclic aromatic amine molecularly imprinted polymer nanospheres with surface-bound dithioester groups (haa-MIP) were firstly synthesized via reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization. Then, a series of core-shell structural heterocyclic aromatic amine molecularly imprinted polymer nanospheres with hydrophilic shells (MIP-HSs) were subsequently prepared by grafting the hydrophilic shells on the surface of haa-MIP via on-particle RAFT polymerization of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA), and diethylaminoethyl methacrylate (DEAEMA). The haa-MIP nanospheres showed high affinity and specific recognition toward harmine and its structural analogs in organic solution of acetonitrile, but lost the specific binding ability in aqueous solution. However, after the grafting of the hydrophilic shells on the haa-MIP particles, the surface hydrophilicity and water dispersion stability of the polymer particles of MIP-HSs greatly improved. The binding of harmine by MIP-HSs with hydrophilic shells in aqueous solutions is about two times higher than that of NIP-HSs, showing an efficient molecular recognition of heterocyclic aromatic amines in aqueous solution. The effect of hydrophilic shell structure on the molecular recognition property of MIP-HSs was further compared. MIP-PIA with carboxyl groups containing hydrophilic shells showed the highest selective molecular recognition ability to heterocyclic aromatic amines in aqueous solution.

Effect of Polymer Shell Structure of a Gamma-ray Shielding Film Prepared Using Composite Material on Shielding Performance

Medical protective clothing should be flexible to ensure free movement of healthcare personnel. This study aimed to investigate the effects of a polymer’s physical properties on the particle composition of a shielding material, constituent component miscibility, and shielding performance. To ensure flexibility by reducing the thickness of the shielding garment, polymer-based composite materials are mainly used as shielding materials. The shielding performance varies depending on whether the polymer used is in an emulsion or powder state. In this study, we found that a shielding film manufactured through an injection process after mixing a polymer in a powder form with tungsten powder exhibited 0.95%–2.5% higher shielding performance than that manufactured using the calendering process with an emulsion polymer. The shell structure formed when using the powder polymer maintains the spacing between the particles owing to the double coating of the tungsten particles and improves their dispersion. Additionally, the primary issue when combining an emulsion polymer and shielding material, that is the aggregation between the shielding material particles and between the polymer particles, could be alleviated, resulting in improved shielding performance. We concluded that the polymer-powder mixing method contributes to the reproducibility of the process technology when manufacturing shielding films.

Synthesis and Characterization if Large Particle Size Self-Matting Core-shell Acrylic Resin

Acrylic resin plays an important role in leather-making, such as finishing agent, filler and tanning agent. Acrylic resin can be easily fabricated via conventional emulsion polymerization, but how to prepare large particle size with self-matting effect has always been a challenge. In this paper, a continuous three-stage polymerization method: seed-polymerization coupled core-polymerization and shell polymerization was employed to prepare large particle size self-matting acrylic resin emulsion. Simultaneously, the effect of feeding methods on particles size and the effects of latex particle size, shell structure and cross-linking degree on the morphology and gloss of coating were investigated. The Z-average size of PBA seed latex particles was 213.4 nm for semi-continuous feeding method but 82.3nm for batch feeding method. After three-time continuous growth, the seed emulsion turned into core emulsion, and the particle size of core latex reached about 700nm. In third stages ofshell polymerization, the core emulsion was changed into core-shell emulsion, and the latex particle size increased further to 804nm. The latex particle size, core-shell structure and cross-linking degree of shell layer were found to influence the gloss of the coating. Large latex particle size imparted the film spherical micro-rough surface, soft-core combined with hard-shell structure led to deformation resistant during film formation and cross-linking of shell layer increased the densification of shell layer, all contributed to the coating rough surface, as a result, increasing the matting effect of the coating. Finally, the leather gloss was reduced from 5.8° to 1.2°.

EVALUATION OF 67Ga CROSS SECTIONS USING EXIFON CODE FOR MEDICAL APPLICATIONS

Radioisotopes play very important roles in nuclear medicine for imaging and therapeutic applications. In the present studies, model calculation of excitation function for production of 67Ga radioisotope was performed using the EXIFON code, a nuclear reaction cross sections theoretical model code, for the reaction 65Cu(α, 2n)67Ga. The work was performed in the incident alpha energy range of 0 - 40 MeV. Similarly, the Q-value software (interface) was used for the calculation of reaction threshold and Q-value energies of the reaction of interest and were respectively found to be 14.97 MeV and -14.10 MeV. The calculated excitation function has a peak value of 1025 mb around 25 MeV incident energy. The results from the EXIFON code were compared with the experimentally measured cross sections data retrieved from IAEA database, the EXFOR database, as well as the theoretical data from Talys code via its library, the TENDL-2019. Our results partially agree with the theoretical data from Talys code (via the TENDL-2019 library) within the investigated energy region. The results however overestimated the measured (experimental) data and only agree in shape of the excitation function. The present work does not consider the effect of shell structure during the execution of the EXIFON model code. This work could be of importance to the developers and users of nuclear reaction model codes for new developments and enhancements of the existing codes, as well as to serve as a rough guide for experimentalists during production of radioisotopes for nuclear medicine applications

Effect of different shell structure on lithium storage properties of MoS2 anode

Hollow mesoporous carbon sphere shell (HMCSS) structure of MoS 2 @C and mesosphere petal-like shell (MPLS) structure of TiO 2 @MoS 2 are synthesized by a facile strategy. HMCSS structure can effectively addressed the volume expansion and poor electrical conductivity of MoS 2 , which show that HMCSS structure of MoS 2 @C has higher discharge capacity, better rate capability and cycling performance than MPLS structure of TiO 2 @MoS 2 and pure MoS 2 . • HMCSS structure of MoS 2 @C and MPLS structure of TiO 2 @MoS 2 are synthesized by a facile strategy. • MoS 2 @C exhibit high capacity, remark cycling stability and rate capability compared with TiO 2 @MoS 2 and pure MoS 2 . • The volume expansion and poor electrical conductivity of MoS 2 can be effectively addressed simultaneously. MoS 2 , with a high theoretical specific capacity (670 mAh/g), is a good alternative to traditional graphite as anode for lithium ion batteries (LIBs). Poor conductivity and serious volume expansion during charging and discharging process, however, result in poor cycle performance and rate performance of MoS 2 anode for LIBs. Here, the TiO 2 coated in mesosphere-petal-like shell (MPLS) structure of MoS 2 (TiO 2 @MoS 2 ) and MoS 2 encapsulated in hollow mesoporous carbon spheres shell (HMCSS) structure (MoS 2 @C) are obtained, and effect of different shell structure on lithium storage properties of MoS 2 are investigated. The results show that MoS 2 @C exhibits higher discharge capacity, better rate capability and cycling performance than TiO 2 @MoS 2 and pure MoS 2 . The significantly enhanced charge and discharge performance of MoS 2 @C can be attributed to the improvement of electric conductivity and the inhibition of volume expansion result from the introduction of HMCSS structure. Also, TiO 2 @MoS 2 demonstrates remarkable lithium storage performance in comparison with pure MoS 2 , which is ascribe to MPLS structure of MoS 2 assembled from corresponding 2D nanosheets that facilitates the penetration of electrolyte and provides more sites to accommodate Li + , and which is also attribute to TiO 2 as effective mechanical support and thus alleviate volume expansion and aggregation of MoS 2 during charging and discharging process. It is believed that the different shell structure used in MoS 2 provides a novel approach to enhance the lithium storage performance of metal sulfide.

α -cluster formation and decay: The role of shell structure

Shell structure effects on $\ensuremath{\alpha}$-cluster formation and decay are studied by using the quartetting wave function approach (QWFA). Both the intrinsic and center-of-mass (c.o.m.) motions of an $\ensuremath{\alpha}$ cluster inside a core nucleus are investigated with different contributing shell model wave functions. The overlap between intrinsic wave functions of four nucleons in the $\ensuremath{\alpha}$-like quartet state and in a free $\ensuremath{\alpha}$ particle is analyzed in detail. The change of the effective potential describing the c.o.m. motion of the quartet is explicitly shown for the major shell closures $Z=82$ and $N=126$. It is found that both the $\ensuremath{\alpha}$-cluster formation probability and the half-life are sensitive to the quartet shell model states. By extending the QWFA calculations from $^{212}\mathrm{Po}$ to $\ensuremath{\alpha}$ emitters with one or two extra nucleons, we show that the bound state and scattering wave functions of the $\ensuremath{\alpha}$ cluster are changed accordingly. The calculated $\ensuremath{\alpha}$-decay half-lives agree nicely with the experimental data.

Shell inhibition on production of N = 126 isotones in multinucleon transfer reactions

The multinucleon transfer process is one promising approach to produce exotic nuclei around the last “waiting point” in the r-process. However, the reliable reaction combinations are still ambiguous so far. We quantitatively evaluate the relative shell inhibition on production cross sections for producing N=126 isotones for the first time with definition of a relative shell inhibition factor. The results suggest that the combinations characterized by double closed shell structure are unfavorable for producing unknown N=126 isotones. It is demonstrated that the reactions 136Xe + 208Pb and 136Xe + 198Pt are not the good candidates. By investigating the yield contributions in main evaporation channels, we find that for producing 200W the effects of shell structure on production cross sections are mainly from de-excitation process. Also, the weak incident energy dependence of cross sections for producing N=126 isotones is revealed with relevance between evaporation probabilities and excitation energy distributions of primary fragments.

Experimental research on the mechanism of chemical energy conversion to light energy under thermal induction

Since the discovery of glare illuminators, considerable efforts have been devoted to achieving a breakthrough of high light intensity on the order of magnitude. In this paper, we prepared strong flash blinding agents for the first time by using aluminum powder, oxidant, and adhesive as the main materials, and tris-(8-hydroxyquinolinato) aluminum (Al2q3), triazoindolizine, or nano zinc oxide, etc. as electronic output brightener after mixing and granulation according to the developed formulation. It was discovered that the luminescence intensity was related to the thermal effect of the substance while the brightener only served as an auxiliary brightening effect to achieve energy non-destructive conversion. With the same formula, the luminescence intensities of glaze agents with ADN and potassium perchlorate as oxidants were slightly higher than that of ammonium perchlorate oxidant; the brightening effect of nano-zinc oxide was slightly higher than those of tris-(8-hydroxyquinolinato) aluminum (Al2q3) and triazoindolizine. The luminescence intensity of the substance with a high thermal effect value was high, but the luminescence time was slightly short. Under identical conditions, the luminescence effect of nano-aluminum powder was obviously better than that of micro-aluminum powder with the highest luminescence intensity of 3.9 × 1010 ~ 1.9 × 1011 cd and the luminescence time of 39 - 48 ms. The effects of shell material and structure and the effect of heat-induced mode on the luminescence intensity were also investigated. The luminescence intensity of the glare agent with a high shell strength was high, but the luminescence time was slightly short. Moreover, the energy level of the brightener is excited under the induction of high temperatures, which leads to a blue shift to promote the chemical reaction of the material in a favorable direction. Finally, the optical radiation of the thermally induced high-temperature combustion system was analyzed from the aspects of thermal effect, combustion temperature, and chemiluminescence effect. A way to improve the optical radiation intensity of a high-temperature combustion system was proposed.

Effect of shell phase composition on the dielectric property and energy density of core‐shell structured BaTiO3 particles modified poly(vinylidene fluoride) nanocomposites

AbstractDielectric nanocomposites have attracted much attention due to their wide applications in electronics and electrical industry. Recently, incorporating core‐shell nanoparticles into polymer matrix to improve the dielectric properties of nanocomposites has been widely reported. Tailoring the interfacial region between the polymer and the nanoparticles plays a crucial role in achieving the desired dielectric and energy storage properties of nanocomposites. However, the effect of shell structure in the interface region on the dielectric and energy storage properties is rarely studied. Based on this, core‐shell BaTiO3 nanoparticles with two different shell polymers, a “hard‐soft” copolymer of methyl methacrylate and butyl acrylate (P[MMA‐BA]) and a “hard” homopolymer of methyl methacrylate (PMMA), were prepared in this paper. The effect of core‐shell BaTiO3 nanoparticles with different shell structures on the dielectric and energy storage properties of poly(vinylidene fluoride) (PVDF) was investigated in depth. Due to the formation of a tight interfacial region between P(MMA‐BA)@BT and PVDF matrix, P(MMA‐BA)@BT/PVDF nanocomposites not only have low dielectric loss but also higher energy efficiency than PMMA@BT/PVDF nanocomposites. This study suggests a potential strategy that fabricating a “hard‐soft” copolymer shell on BaTiO3 surface can obtain desirable energy storage efficiency than the single “hard” shell structure in dielectric nanocomposites.

Excitation energy partition in fission

The transformation of an atomic nucleus into two excited fission fragments is modeled as a strongly damped evolution of the nuclear shape. As in previous studies, it is assumed that the division of mass and charge is frozen in at a critical neck radius of c0=2.5fm. In order to also determine the energetics, we follow the system further until scission occurs at a smaller neck radius, at which point the shapes of the proto-fragments are extracted. The statistical energy available at scission is then divided on the basis of the respective microscopic level densities. This approach takes account of important (and energy-dependent) finite-size effects. After the fragments have been fully accelerated and their shapes have relaxed to their equilibrium forms, they undergo sequential neutron evaporation. The dependence of the resulting mean neutron multiplicity on the fragment mass, ν¯(A), including the dependence on the initial excitation energy of the fissioning compound nucleus, agrees reasonably well with observations, as demonstrated here for 235U(n,f), and the sawtooth appearance of ν¯(A) can be understood from shell-structure effects in the level densities.

Ionic Diffusion and Drug Release Behavior of Core–Shell-Functionalized Alginate–Chitosan-Based Hydrogel

This paper reports the core–shell structure effects in calcium alginate (CaALG) microbeads due to the threshold water level for phase transition and correlates these properties with respect to pH and electrical conductivity. Further, in this study, we used a novel microfluidic device for drug release testing to study the programmed release of risedronate (RIS-anti-osteoporotic drug) encapsulated in pH-responsive CaALG–chitosan (CHT) microbeads. Our microfluidic device contains a single straight microchannel containing a steplike barrier design used to restrict the mobility of the microbeads at the sample detection zone. For optical and fluorescence microscopy, single fluorescently labeled CaALG–CHT microbead containing RIS was placed in the sample detection zone by flowing through the inlet port with ultrapure water. The RIS release behavior from the microbeads at different pH (2.1, 4, 6.8, and 7.4) conditions was determined by using a spectrophotometer connected to the outlet port of the device. Results of our first study showed that the decrease in the concentration of CaCl2 increases the swelling rate in CaALG microbeads. Maximum swelling was achieved with the lowest molar concentration of CaCl2 used for fabrication of CaALG microbeads. Further, electrical current–voltage characteristic shows the nature of ionic mobility with respect to varying levels of pH indicating electrokinetic forces developed in the CaALG microbeads. By using a microfluidic device for drug release testing, we demonstrated that a sustained release delivery system for RIS can be prepared by coating with pH-sensitive and biodegradable CaALG–CHT. The CaALG–CHT microbeads used for encapsulating RIS are resistant to the acidic environment of the stomach. This may improve the therapeutic effectiveness and reduce the gastric adverse effects associated with RIS by preventing its decomposition in the acidic condition of stomach. The newly developed microfluidic device for drug release testing may find applications in screening novel drugs and delivery systems.

Effect of shell structure of Ti-immobilized metal ion affinity chromatography core-shell magnetic particles for phosphopeptide enrichment

Magnetic materials in sample preparation for shotgun phosphoproteomics offer several advantages over conventional systems, as the enrichment can be achieved directly in solution, but they still suffer from some drawbacks, due to limited stability and selectivity, which is supposed to be affected by the hydrophilicity of the polymeric supports used for cation immobilization. The paper describes the development of an improved magnetic material with increased stability, thanks to a two-step covering of the magnetic core, for the enrichment of phosphopeptides in biological samples. Four materials were prepared featuring a polymeric shell with tunable hydrophilicity, obtained by “grafting from” polymerization of glycidyl methacrylate with 0–8.3% of polyethylene glycol methacrylate (PEGMA), the latter used to modulate the hydrophilicity of the material surface. Finally, the materials were functionalized with iminodiacetic acid for Ti4+ ion immobilization. The materials were analyzed for their composition by a combination of CHN elemental analysis and thermogravimetric analysis, also hyphenated to gas chromatography and mass spectrometric detection. Surface characteristics were evaluated by water contact angle measurements, scanning electron microscopy and energy dispersive X-ray spectrometry. These materials were applied to the enrichment of phosphopeptides from yeast protein digests. Peptides were identified by proteomics techniques using nano-high performance liquid chromatography coupled to mass spectrometry and bioinformatics. Qualitatively the peptides identified by the four systems were comparable, with 1606–1693 phosphopeptide identifications and a selectivity of 47–54% for all materials. The physico-chemical features of the identified peptides were also the same for the four materials. In particular, the grand average of hydropathy index values indicated that the enriched phosphopeptides were hydrophilic (ca. 90%), and only some co-enriched non-phosphorylated peptides were hydrophobic (21–28%), regardless of the material used for enrichment. Peptides had a pI ≤ 7, which indicated a well-known bias for acidic peptides binding, attributed to the interaction with the metal center itself. The results indicated that the enrichment of phosphopeptides and the co-enrichment of non-phosphorylated peptides is mainly driven by interactions with Ti4+ and does not depend on the amount of PEGMA chains in the polymer shell.

Effect of shell structure on the fission of sub-lead nuclei

Fission of atomic nuclei often produces mass asymmetric fragments. However, the origin of this asymmetry was believed to be different in actinides and in the sub-lead region [A. Andreyev {\it et al.}, Phys. Rev. Lett. {\bf 105}, 252502 (2010)]. It has recently been argued that quantum shell effects stabilising pear shapes of the fission fragments could explain the observed asymmetries in fission of actinides[G. Scamps and C. Simenel, Nature {\bf 564}, 382 (2018)]. This interpretation is tested in the sub-lead region using microscopic mean-field calculations of fission based on the Hartree-Fock approach with BCS pairing correlations. The evolution of the number of protons and neutrons in asymmetric fragments of mercury isotope fissions is interpreted in terms of deformed shell gaps in the fragments. A new method is proposed to investigate the dominant shell effects in the pre-fragments at scission. We conclude that the mechanisms responsible for asymmetric fissions in the sub-lead region are the same as in the actinide region, which is a strong indication of their universality.

Proton-neutron force and proton single-particle strength in Sc, F, and Li isotopes

In the present work, the effect of proton-neutron interaction and its different components, i.e., central, spin-orbit, and tensor force, on proton shell-structure of odd-$A$ Sc, F, and Li isotopes is studied within the nuclear shell model framework. It has been observed that the central force possesses strong-orbital node $(nl)$ and weak-spin $(j)$ dependency, and plays a key role in producing changes in proton shell-structure. The integrated effect of proton shell-structure and proton single-particle strength in building the level structure of $^{49,53,55}\mathrm{Sc}$, $^{23,25}\mathrm{F}$, and $^{9}\mathrm{Li}$ isotopes are also discussed. Proton single-particle strength in the level structure of above-mentioned nuclei is studied using proton-transfer spectroscopic factors. It has been particularly discerned that the low energy of the ${\frac{3}{2}}_{1}^{\ensuremath{-}}$ state of $^{55}\mathrm{Sc}$ is caused by the weakening of the $N=34$ semimagic gap, the high energy of the ${\frac{1}{2}}_{1}^{+}$ state of $^{23}\mathrm{F}$ is originated from an increase in the energy gap between orbitals $\ensuremath{\pi}1{s}_{1/2}$ and $\ensuremath{\pi}0{d}_{5/2}$ at $N=14$, and the high energy of the ${\frac{1}{2}}_{1}^{\ensuremath{-}}$ state of $^{9}\mathrm{Li}$ is originated from the large energy gap between $\ensuremath{\pi}0{p}_{1/2}$ and $\ensuremath{\pi}0{p}_{3/2}$ orbitals which remained nearly constant from $^{5}\mathrm{Li}$ to $^{9}\mathrm{Li}$.

A Systematic Study on the Existence of 7-9B, 16-19Ne, 8-11C, 23-30P and 26-32S Nuclei via Cluster Decay in the Super Heavy Region

Based on the Coulomb and Proximity Potential Model, we have studied the decay probabilities of various exotic nuclei from even-even nuclei in the super heavy region. The half-lives and barrier penetrability for the decay of exotic nuclei such as 7-9B, 16-19 Ne, 8-11 C, 23-30 P and 26-32 S from the isotopes 274-332116,274-334 118 and 288-334120 are determined by considering them as spherical as well as deformed nuclei. The effect of ground state quadrupole (β2), Octupole (β3) and hexadecapole (β4) deformation of parent, daughter and cluster nuclei on half- lives and barrier penetrability were studied. Calculations have done for the spherical nuclei and deformed nuclei in order to present the effects of the deformations on half-lives. It is found that height and shape of the barrier reduces by the inclusion of deformation and hence half-life for the emission of different clusters decreases and barrierpenetrability increases. Changes in the half-lives with and without the inclusion of deformation effects are compared in the graph of half -life and barrier penetrability against neutron number of parents. It is evident from the computed half lives that many of the exotic nuclei emissions are probable. Moreover shell structure effects on the half-lives of decay are evident from these plots. Peak in the plot of halflife and dip in the plot of barrier penetrability against neutron number of parent show shell closure at or near to N=184, N=200 and N=212.