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29 results on '"Yasuhisa Abe"'

1. Preventive effect of aripiprazole once monthly on rehospitalization for bipolar disorder: A multicenter 1‐year retrospective mirror image study

Author

Junichi Goto, Masahiro Shono, Yasuhisa Abe, Yasutaka Fujita, Keishi Ueda, Binchi Yoshida, and Yoshihiro Nabeshima

Subjects
antipsychotic agents, bipolar disorder, delayed‐action preparations, patient readmission, retrospective studies, Therapeutics. Pharmacology, RM1-950, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
Abstract

Abstract Aim We conducted a 1‐year retrospective mirror‐image study to investigate the effect of aripiprazole once monthly (AOM) on rehospitalization for bipolar disorder. Methods Participants were recruited from psychiatric emergency and acute care hospitals in western Japan. We included 39 participants with bipolar disorder who had been administered AOM for at least 1 year with no missing medical records during the observational period. The primary outcomes were rehospitalization rate, number of rehospitalizations, total hospitalization days, and time to rehospitalization in the context of overall psychiatric readmissions. The significance level was set at p

Published
2023
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2. Comparative effects of topiroxostat and febuxostat on arterial properties in hypertensive patients with hyperuricemia

Author

Kazuomi Kario, Masafumi Nishizawa, Mari Kiuchi, Arihiro Kiyosue, Fumishi Tomita, Hiroshi Ohtani, Yasuhisa Abe, Hideyo Kuga, Satoshi Miyazaki, Takatoshi Kasai, Makiko Hongou, Takanori Yasu, Jin Kuramochi, Yoshihiro Fukumoto, Satoshi Hoshide, and Ichiro Hisatome

Subjects
arterial stiffness, cardio‐ankle vascular index, hypertension, hyperuricemia, xanthine oxidoreductase inhibitors, Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Elevated serum uric acid is a cardiovascular risk factor in patients with hypertension, even when blood pressure (BP) is well controlled. Xanthine oxidoreductase inhibitors (XORi) reduce serum uric acid levels and have several other potential effects. This multicenter, randomized, open‐label study compared the effects of two XORi, topiroxostat and febuxostat, on arterial stiffness, uric acid levels, and BP in hypertensive patients with hyperuricemia. Patients received topiroxostat 40–160 mg/day or febuxostat 10–60 mg/day, titrated to maintain serum uric acid

Published
2021
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3. Inconsistent Control Status of Office, Home, and Ambulatory Blood Pressure All Taken Using the Same Device: The HI– JAMP Study Baseline Da.

Author

Kazuomi Kario, Satoshi Hoshide, Naoko Tomitani, Masafumi Nishizawa, Tetsuro Yoshida, Tomoyuki Kabutoya, Takeshi Fujiwara, Hiroyuki Mizuno, Keisuke Narita, Takahiro Komori, Yukiyo Ogata, Daisuke Suzuki, Yukako Ogoyama, Akifumi Ono, Kayo Yamagiwa, Yasuhisa Abe, Jun Nakazato, Naoki Nakagawa, Tomohiro Katsuya, and Noriko Harada

Subjects
AMBULATORY blood pressure monitoring, BLOOD pressure, OFFICES, ANTIHYPERTENSIVE agents, HYPERTENSION
Abstract

BACKGROUND Inconsistencies between the office and out-of-office blood pressure (BP) values (described as white-coat hypertension or masked hypertension) may be attributable in part to differences in the BP monitoring devices used. METHODS We studied consistency in the classification of BP control (wellcontrolled BP vs. uncontrolled BP) among office, home, and ambulatory BPs by using a validated “all-in-one” BP monitoring device. In the nationwide, general practitioner-based multicenter HI–JAMP study, 2,322 hypertensive patients treated with antihypertensive drugs underwent office BP measurements and 24-hour ambulatory BP monitoring (ABPM), consecutively followed by 5-day home BP monitoring (HBPM), for a total of seven BP measurement days. RESULTS Using the thresholds of the JSH2019 and ESC2018 guidelines, the patients with consistent classification of well-controlled status in the office (<140 mmHg) and home systolic BP (SBP) (<135 mmHg) (n = 970) also tended to have well-controlled 24-hour SBP (<130 mmHg) (n = 808, 83.3%). The patients with the consistent classification of uncontrolled status in office and home SBP (n = 579) also tended to have uncontrolled 24-hour SBP (n = 444, 80.9%). Among the patients with inconsistent classifications of office and home BP control (n = 803), 46.1% had inconsistent ABPM-vs.-HBPM out-of-office BP control status. When the 2017 ACC/AHA thresholds were applied as an alternative, the results were essentially the same. CONCLUSIONS The combined assessment of the office and home BP is useful in clinical practice. Especially for patients whose office BP classification and home BP classification conflict, the complementary clinical use of both HBPM and ABPM might be recommended. [ABSTRACT FROM AUTHOR]

Published
2023
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4. A dynamical study of fusion hindrance with the Nakajima–Zwanzig projection method

Author

Quentin Hourdillé, Yasuhisa Abe, Caiwan Shen, David Boilley, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Fusion, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Degrees of freedom (physics and chemistry), General Physics and Astronomy, FOS: Physical sciences, Slip (materials science), 01 natural sciences, Term (time), Langevin equation, Nuclear Theory (nucl-th), 0103 physical sciences, Projection method, Order (group theory), Relaxation (approximation), Statistical physics, 010306 general physics
Abstract

A new framework is proposed for the study of collisions between very heavy ions which lead to the synthesis of Super-Heavy Elements (SHE), to address the fusion hindrance phenomenon. The dynamics of the reaction is studied in terms of collective degrees of freedom undergoing relaxation processes with different time scales. The Nakajima–Zwanzig projection operator method is employed to eliminate fast variables and derive a dynamical equation for the reduced system with only slow variables. There, the time evolution operator is renormalised and an inhomogeneous term appears, which represents a propagation of the given initial distribution. The term results in a slip to the initial values of the slow variables. We expect that gives a dynamical origin for the so-called “injection point $s$” introduced by Swiatecki et al. in order to reproduce absolute values of measured cross sections for SHE. A formula for the slip is given in terms of physical parameters of the system, which confirms the results recently obtained with a Langevin equation, and permits us to compare various incident channels.

Published
2021
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5. Erratum: Elimination of fast variables and initial slip: a new mechanism for fusion hindrance in heavy-ion collisions (2019 J. Phys. G: Nucl. Part. Phys . 46 115102)

Author

B. Cauchois, D. Boilley, Caiwan Shen, Yasuhisa Abe, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Fusion, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, 0103 physical sciences, Heavy ion, Slip (materials science), Mechanics, 010306 general physics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019
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6. How accurately can we predict synthesis cross-sections of superheavy elements?

Author

Bartholomé Cauchois, Anthony Marchix, Yasuhisa Abe, Caiwan Shen, David Boilley, Hongliang Lü, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], School of Science, Huzhou Tearchers College, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Fusion, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Fission, Nuclear Theory, Superheavy Elements, Span (engineering), 01 natural sciences, Nuclear physics, superheavy elements, Nuclear Energy and Engineering, 0103 physical sciences, Nuclear Experiment, 010306 general physics, uncertainty analysis, Order of magnitude, Uncertainty analysis, nuclear reactions
Abstract

International audience; Synthesis of superheavy elements beyond oganesson is facing new challenges as new target-projectile combinations are necessary. Guidance from models is thus expected for future experiments. However, hindered fusion models are not well established and predictions in the fission barriers span few MeVs. Consequently, predictions are not reliable. Strategies to constrain both fusion hindrance and fission barriers are necessary to improve the predictive power of the models. But, there is no hope to get an accuracy better than one order of magnitude in fusion-evaporation reactions leading to superheavy elements synthesis.

Published
2018
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7. Synthesis of superheavy elements: Uncertainty analysis to improve the predictive power of reaction models

Author

Caiwan Shen, David Boilley, Hongliang Lü, Yasuhisa Abe, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU), Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], School of Science, Huzhou University, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Mathematical optimization, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, 01 natural sciences, Confidence interval, 25.70.Jj, 24.10.-i, 24.60.Dr, 06.20.-f, Cascade, 0103 physical sciences, Predictive power, Probability distribution, Sensitivity analysis, 010306 general physics, Set (psychology), Fusion mechanism, Uncertainty analysis
Abstract

13 pages, 13 figures, submitted for publication in PRC; International audience; Background: Synthesis of super-heavy elements is performed by heavy-ion fusion-evaporation reactions. However , fusion is known to be hindered with respect to what can be observed with lighter ions. Thus some delicate ambiguities remain on the fusion mechanism that eventually lead to severe discrepancies in the calculated formation probabilities coming from different fusion models. Purpose: In the present work, we propose a general framework based upon uncertainty analysis in the hope of constraining fusion models. Method: To quantify uncertainty associated with the formation probability, we propose to propagate uncertainties in data and parameters using the Monte-Carlo method in combination with a cascade code called KEWPIE2, with the aim of determining the associated uncertainty, namely the 95% confidence interval. We also investigate the impact of different models or options, which cannot be modeled by continuous probability distributions, on the final results. An illustrative example is presented in detail and then a systematic study is carried out for a selected set of cold-fusion reactions. Results: It has been rigorously shown that, at the 95% confidence level, the total uncertainty of the empirical formation probability appears comparable to the discrepancy between calculated values. Conclusions: The results obtained from the present study provide a direct evidence for predictive limitations of the existing fusion-evaporation models. It is thus necessary to find other ways to assess such models for the purpose of establishing a more reliable reaction theory, which is expected to guide future experiments on the production of super-heavy elements.

Published
2016
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8. Tax reform runs into a legislative logjam

Author

Yasuhisa, Abe

Subjects
Japan. Diet -- Tax policy, Japan -- Political aspects, Tax reform -- Analysis, Tax reform -- Planning, Tax reform -- Forecasts and trends, Market trend/market analysis, Company business planning, Regional focus/area studies
Abstract

The divided government in the upper and lower houses of the National Diet in Japan has meant that the proposed tax reform remains virtually stuck in the world of politics with virtually no chance of the legislative opposites coordinating their approach. The tax measures that are set to expire and the prospects for the next diet session are discussed.

Published
2008

9. New Trends in Nuclear Collective Dynamics : Proceedings of the Nuclear Physics Part of the Fifth Nishinomiya-Yukawa Memorial Symposium, Nishinomiya, Japan, October 25 and 26, 1990

Author

Yasuhisa Abe, Hisashi Horiuchi, Kenichi Matsuyanagi, Yasuhisa Abe, Hisashi Horiuchi, and Kenichi Matsuyanagi

Subjects
Nuclear physics, Nuclear fusion, Engineering
Abstract

'New Trends in Nuclear Collective Dynamics'emphasizes research toward understanding collective and statistical aspects of nuclear dynamics. Well-known lecturers from centers of nuclear research present reviews of recent developments. The topics covered are: -order and chaos in finite quantum systems -dissipation in heavy-ion collisions -collective motionsin warm nuclei -time-dependent mean-field theory with collision terms -nuclear fission and multi-dimensional tunneling -large-scale collective motion

Published
2012

10. Improvement of pain and regional osteoporotic changes in the foot and ankle by low-dose bisphosphonate therapy for complex regional pain syndrome type I: a case series

Author

Takuro Wada, Toshihiko Yamashita, Junichi Takada, Yasuhisa Abe, and Kousuke Iba

Subjects
Medicine(all), medicine.medical_specialty, medicine.diagnostic_test, business.industry, medicine.medical_treatment, lcsh:R, lcsh:Medicine, Case Report, General Medicine, Bisphosphonate, medicine.disease, Surgery, Bone remodeling, Osteopenia, Allodynia, Complex regional pain syndrome, medicine.anatomical_structure, Bone scintigraphy, Medicine, medicine.symptom, Ankle, business, Bone pain
Abstract

Introduction Complex regional pain syndrome is characterized by pain, allodynia, hyperalgesia, edema, signs of vasomotor instability, movement disorders, joint stiffness, and regional osteopenia. It is recognized to be difficult to treat, despite various methods of treatment, including physiotherapy, calcitonin, corticosteroids, sympathetic blockade, and nonsteroidal anti-inflammatory drugs. Pathophysiologically, complex regional pain syndrome reveals enhanced regional bone resorption and high bone turnover, and so bisphosphonates, which have a potent inhibitory effect on bone resorption, were proposed for the treatment of complex regional pain syndrome. Case presentation A 48-year-old Japanese man with complex regional pain syndrome type I had severe right ankle pain with a visual analog scale score of 59 out of 100 regardless of treatment with physiotherapy and nonsteroidal anti-inflammatory drugs for five months. Radiographs showed marked regional osteoporotic changes and bone scintigraphy revealed a marked increase in radioactivity in his ankle. One month after the start of oral administration of risedronate (2.5 mg per day), his bone pain had fallen from a VAS score of 59 out of 100 to 18 out of 100. Bone scintigraphy at 12 months showed a marked reduction in radioactivity to a level comparable to that in his normal, left ankle. On the basis of these results, the treatment was discontinued at 15 months. At 32 months, our patient had almost no pain and radiographic findings revealed that the regional osteoporotic change had returned to normal. A second 48-year-old Japanese man with complex regional pain syndrome type I had severe right foot pain with a visual analog scale score of 83 out of 100 regardless of treatment with physiotherapy and nonsteroidal anti-inflammatory drugs for nine months. Radiographs showed regional osteoporotic change in his phalanges, metatarsals, and tarsals, and bone scintigraphy revealed a marked increase in radioactivity in his foot. One month after the start of oral administration of alendronate (35 mg per week), his bone pain had fallen from a visual analog scale score of 83 out of 100 to 30 out of 100 and, at nine months, was further reduced to 3 out of 100. The treatment was discontinued at 15 months because of successful pain reduction. At 30 months, our patient had no pain and the radiographic findings revealed marked improvement in regional osteoporotic changes. Conclusions We believe low-dose oral administration of bisphosphonate is worth considering for the treatment of idiopathic complex regional pain syndrome type I accompanied by regional osteoporotic change.

Published
2011

11. Dynamical effects in the fusion hindrance

Author

David Boilley, Yasuhisa Abe, B. G. Giraud, Caiwan Shen, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Fusion, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, QC1-999, Dynamics (mechanics), 01 natural sciences, Coupling (physics), Classical mechanics, Amplitude, 0103 physical sciences, Radial motion, 010306 general physics, Reduction (mathematics), Adiabatic process, Nuclear Experiment, Fusion mechanism, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

3 figures; International audience; It is well known that there is a hindrance of fusion in collisions with heavy nuclei that plays a decisive role in synthesis of the super-heavy elements (SHE). The origin of the fusion hindrance is nowadays qualitatively understood but there are still quantitative ambiguities on the dynamics of the fusion mechanism and the predictions need to be assessed. In this communication, we stress the fact that dynamical effects play a crucial role in the amplitude of the reduction of the fusion probability.We found that the fast evolution of the neck degree of freedom affects the slow radial motion, i.e., the fusioning motion, through a dynamical coupling. We showed that we could do a so-called adiabatic elimination of the fast variable in the coupled equation, resulting in an effective one-dimensional equation for the radial motion with a shift of the starting point. This treatment of the dynamical coupling leads to a larger hindrance.

Published
2011
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12. Compound Nucleus Reaction Theory for Synthesis of Super-Heavy Elements

Author

David Boilley, Caiwan Shen, B. G. Giraud, Yasuhisa Abe, Research Center for Nuclear Physics ( RCNP ), Osaka University [Osaka], School of Science, Huzhou Tearchers College, Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Institut de Physique Thèorique, CEA/DSM, L. Bonneau, N. Dubray, F. Gunsing, B. Jurado, Research Center for Nuclear Physics (RCNP), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU), L. Bonneau, N. Dubray, F. Gunsing, B. Jurado, and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Fusion, Chemical substance, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Chemistry, Physics, QC1-999, Transactinide element, 01 natural sciences, medicine.anatomical_structure, Computational chemistry, 0103 physical sciences, medicine, Statistical physics, 010306 general physics, Nucleus, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

International audience; Present status of theory for synthesis of Super-Heavy Element (SHE) is reported, based on the compound nucleus reaction. Specific aspects are discussed in fusion and survival probabilities. They are the hindrance of fusion in the former and the fragility of the compound nucleus in the latter. Examples of applications are given.

Published
2009
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13. Heavy-Ion Fusion Mechanism And Predictions of Super-Heavy Elements Production

Author

Yasuhisa Abe, Caiwan Shen, David Boilley, Bertrand G. Giraud, Grigory Kosenko, Matko Milin, Tamara Niksic, Suzana Szilner, Dario Vretenar, Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], School of Science, Huzhou Tearchers College, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Institut de Physique Thèorique, CEA/DSM, Department of Physics, Omsk University, Research Center for Nuclear Physics ( RCNP ), Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Fusion, Cross section, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Chemistry, Degrees of freedom (statistics), Transactinide element, Nuclear physics, Super-heavy elements, 25.70, Jj, 25.70. Lm, 27.90. +b, Nucleosynthesis, Diffusion (business), [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Fusion mechanism, Transuranium element, Heavy-ion Fusion, Fusion hindrance
Abstract

International audience; Fusion process is shown to firstly form largely deformed mono-nucleus and then to undergo diffusion in two-dimensions with the radial and mass-asymmetry degrees of freedom. Examples of prediction of residue cross sections are given for the elements with Z=117 and 118.

Published
2009
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14. Analysis of the Fusion Hindrance in Mass-symmetric Heavy Ion Reactions

Author

Caiwan Shen, Qingfeng Li, David Boilley, Yasuhisa Abe, School of Science, Huzhou Tearchers College, Research Center for Nuclear Physics ( RCNP ), Osaka University [Osaka], Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Research Center for Nuclear Physics (RCNP), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Fusion, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Projectile, Liquid drop, FOS: Physical sciences, Coulomb barrier, Saddle point, 01 natural sciences, Molecular physics, Contact point, Two center liquid drop model, Nuclear Theory (nucl-th), Semi-empirical mass formula, 0103 physical sciences, Heavy ion, Atomic number, 010306 general physics, Nuclear Experiment, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Fusion hindrance
Abstract

The fusion hindrance, which is also denominated by the term extra-push, is studied on mass-symmetric systems by the use of the liquid drop model with the two-center parameterization. Following the idea that the fusion hindrance exists only if the liquid drop barrier (saddle point) is located at the inner side of the contact point after overcoming the outer Coulomb barrier, the reactions in which two barriers are overlapped with each other are determined. It is shown that there are many systems where the fusion hindrance does not exist for the atomic number of projectile or target nucleus $Z\leq43$, while for $Z>43$, all of the mass-symmetric reactions are fusion-hindered., 6 pages, 4 figures. to be published in Sci. in China G

Published
2009
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15. From Di-Nucleus to Mono-Nucleus - Neck Evolution in Fusion of Massive Systems

Author

B. G. Giraud, Yasuhisa Abe, Caiwan Shen, David Boilley, Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], School of Science, Huzhou University, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Research Center for Nuclear Physics ( RCNP ), School of Science, Huzhou Tearchers College, Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Institut Physique Théorique, Direction des Sciences de la Matière, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Physics, Nuclear and High Energy Physics, Fusion, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, General Physics and Astronomy, FOS: Physical sciences, Superheavy Elements, 01 natural sciences, Two degrees of freedom, Ion, Superdeformation, Three degrees of freedom, Nuclear Theory (nucl-th), medicine.anatomical_structure, 0103 physical sciences, medicine, Atomic physics, 010306 general physics, Nuclear Experiment, Nuclear theory, Nucleus, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

Dynamics of the neck degree of freedom during fusioning process between heavy ions is studied. Time scales of the three degrees of freedom (the relative distance, the neck and the mass-asymmetry) are studied, showing an early equilibration of the neck. This means that a di-nucleus formed by the incident combination of ions quickly forms a mono-nucleus with a superdeformation during the fusion process and that the other two degrees of freedom have to be solved in a coupled way. A brief introduction of Langevin approach and dissipation-fluctuation dynamics is also given and of the application to the synthesis of the superheavy elements., 6 pages, 3 figures, Proceedings of the Japanese French Symposium - New paradigms in Nuclear Physics, Paris, 29th September - 2nd October, to be published in Int. J. of Modern Physics E

Published
2009
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16. Di-nucleus dynamics towards fusion of heavy nuclei

Author

David Boilley, Caiwan Shen, Yasuhisa Abe, B. G. Giraud, G. I. Kosenko, Research Center for Nuclear Physics ( RCNP ), Osaka University [Osaka], School of Science, Huzhou Tearchers College, Department of Physics, Omsk University, Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Institut de Physique Théorique - UMR CNRS 3681 ( IPHT ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Research Center for Nuclear Physics (RCNP), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Fusion, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Dynamics (mechanics), Time evolution, General Physics and Astronomy, Superheavy Elements, 7. Clean energy, 01 natural sciences, Nuclear shape, Distribution function, Classical mechanics, medicine.anatomical_structure, Saddle point, 0103 physical sciences, medicine, 010306 general physics, Nucleus, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

This work has been first presented at : First Workshop on State of the Art in Nuclear Cluster Physics, 13/16-05-2008 Strasbourg (France); International audience; The Two-Step Model for fusion of massive systems is briefly recapitulated, which clar- ifies the mechanism of so-called fusion hindrance. Since the neck changes the potential landscape, especially the height of the conditional saddle point, time evolution of the neck degree of freedom plays a crucial role in fusion. We analytically solve time-evolution of nuclear shape of the composite system from di-nucleus to mono-nucleus. The time- dependent distribution function of the neck is obtained, which elucidates dynamics of fusion processes in general, and thus, is useful for theoretical predictions on synthesis of the superheavy elements with various combinations of incident heavy ions.

Published
2008
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17. What can we learn from the fission time of the super-heavy elements?

Author

David Boilley, A. Marchix, Yoann Lallouet, Florian Gimbert, David Wilgenbus, Yasuhisa Abe, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Research Center for Nuclear Physics ( RCNP ), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Fission, General Physics and Astronomy, Transactinide element, Blocking (statistics), 01 natural sciences, Island of stability, 010305 fluids & plasmas, Nuclear physics, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Saddle, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

International audience; Recent experiments performed at GANIL with a crystal blocking technique have shown direct evidences of long fission times in the Super-Heavy Elements (SHE) region. Aimed to localize the SHE island of stability, can these experiments give access to the fission barrier and then to the shell-correction energy? In this paper, we calculate the fission time of heavy elements by using a new code, KEWPIE2, devoted to the study of the SHE.We also investigate the effect of potential structure beyond the saddle on the fission time.

Published
2007
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18. Fusion hindrance and synthesis of superheavy elements

Author

Grigori Kosenko, B. G. Giraud, David Boilley, B. Bouriquet, Caiwan Shen, Anthony Marchix, Yasuhisa Abe, Research Center for Nuclear Physics (RCNP), Osaka University [Osaka], Physics Department, Omsk University, School of Science, Huzhou Tearchers College, Department of Nuclear Physics (DNP), Australian National University (ANU), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU), Service de Physique Théorique (SPhT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Lion, Michel, Research Center for Nuclear Physics ( RCNP ), Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Service de Physique Théorique ( SPhT ), and Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Physics, [PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], Nuclear and High Energy Physics, Fusion, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Nuclear Theory, Shell (structure), Coulomb barrier, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Atomic and Molecular Physics, and Optics, Cold fusion, Saddle point, 0103 physical sciences, 25.70.Jj - 25.70.Gh - 24.10.Pa, Nuclear fusion, Atomic physics, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nuclear Experiment, Beam (structure), Excitation, Nuclear Physics
Abstract

A mechanism for fusion hindrance is clarified, based on the observation that the sticking configuration of projectile and target is located outside of the conditional saddle point. Accordingly, the fusion process is described by two sequential steps of passing over the Coulomb barrier and shape evolution toward the spherical compound nucleus. The latter one is indispensable in massive systems. With the use of a two-step model, excitation functions of fusion reaction are calculated for various combinations of projectiles and targets which lead to superheavy elements. The hindered fusion excitation measured is reproduced precisely without any adjustable parameter. Combined with survival probabilities calculated by the statistical theory of decay, excitation functions for residues of superheavy elements are calculated to compare with the systematic data measured for the cold fusion path. The peak positions and the widths are correctly reproduced, though it is necessary to reduce the shell correction energies of the compound nuclei predicted by the structure calculations in order to reproduce their absolute values. Predictions are made for a few unknown heavier elements. Furthermore, a preliminary attempt toward the shell closure N = 184 is also presented using a neutron-rich secondary beam.

Published
2005
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19. Theory of fusion hindrance and synthesis of the superheavy elements

Author

Caiwan Shen, Bertrand Bouriquet, Yasuhisa Abe, and Grigori Kosenko

Subjects
Nuclear Theory (nucl-th), Nuclear physics, Physics, Nuclear and High Energy Physics, Fusion, Nuclear Theory, FOS: Physical sciences, Nuclear fusion, Actinide, Superheavy Elements
Abstract

The two-step model for fusion reactions of massive systems is briefly reviewed.By the use of fusion probabilities obtained by the model and of survival probabilities obtained by the new statistical code, we predict residue cross sections for 48Ca+actinide systems leading to superheavy elements with Z=114, 116 and 118., 7 pages, 4 figures, Halong Bay meeting proceeding

Published
2003

20. Fusion dynamics of massive heavy-ion systems

Author

Takahiro Wada, Jing Dong Bao, B. G. Giraud, David Boilley, Yasuhisa Abe, Grigori Kosenko, Cai Wang Shen, Grand Accélérateur National d'Ions Lourds ( GANIL ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Lion, Michel, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Caen Normandie (UNICAEN), Normandie Université (NU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], Physics, Fusion, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Physics and Astronomy (miscellaneous), Dynamics (mechanics), Superheavy Elements, Ion, medicine.anatomical_structure, Phase (matter), medicine, Heavy ion, Atomic physics, Nuclear Experiment, Nucleus, Fusion mechanism, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th]
Abstract

A two-step model is proposed for the fusion mechanism of massive heavy-ion systems which is the most unknown part in the reaction theory for the synthesis of the superheavy elements. It consists of the approaching phase of incident ions and the dynamical shape evolution of the amalgamated system toward the spherical compound nucleus. Preliminary results are presented.

Published
2001

25. Perspectives of Nuclear Fission.

Author

Yasuhisa ABE

Subjects
NUCLEAR fission, EVAPORATION (Chemistry), THOMAS-Fermi theory, PHASE space, GENERALIZED spaces
Published
1995

27. On Fission Dynamics.

Author

Yasuhisa ABE

Subjects
NUCLEAR fission, NUCLEAR matter, DEEP inelastic collisions, STOPPING power (Nuclear physics), NEUTRON multiplicity, RADIOACTIVE decay, BROWNIAN motion, LANGEVIN equations
Published
1995
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28. Dynamical decay of nuclei at high temperature: competition between particle emission and fission decay

Author

C. Grégoire, H. Delagrange, Yasuhisa Abe, F. Scheuter, Grand Accélérateur National d'Ions Lourds (GANIL), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Diffusion equation, Fission, Time evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, Formalism (philosophy of mathematics), Particle decay, Particle emission, Excited nucleus, Nuclear fusion, Atomic physics, Nuclear Experiment
Abstract

A generalized diffusion equation is propounded to follow the time evolution of an excited nucleus towards fission including along the particle decay. This theoretical model is built in order to try to analyse the anomalous behaviour of particle emission observed in many experimental data for heavy-ion induced reactions. Some calculations for the systems194Hg,170Yb and248Cf are presented. A possible extension of this generalized formalism is suggested to deal more consistently with the experimental data.

Published
1986
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29. Synthesis of superheavy elements: Uncertainty analysis to improve the predictive power of reaction models.

Author

Hongliang Lü, Boilley, David, Yasuhisa Abe, and Caiwan Shen

Subjects
*HEAVY ion fusion reactions, *SUPERHEAVY elements, *UNCERTAINTY
Abstract

Background: Synthesis of superheavy elements is performed by heavy-ion fusion-evaporation reactions. However, fusion is known to be hindered with respect to what can be observed with lighter ions. Thus some delicate ambiguities remain on the fusion mechanism that eventually lead to severe discrepancies in the calculated formation probabilities coming from different fusion models. Purpose: In the present work, we propose a general framework based upon uncertainty analysis in the hope of constraining fusion models. Method: To quantify uncertainty associated with the formation probability, we propose to propagate uncertainties in data and parameters using the Monte Carlo method in combination with a cascade code called kewpie2, with the aim of determining the associated uncertainty, namely the 95% confidence interval. We also investigate the impact of different models or options, which cannot be modeled by continuous probability distributions, on the final results. An illustrative example is presented in detail and then a systematic study is carried out for a selected set of cold-fusion reactions. Results: It is rigorously shown that, at the 95% confidence level, the total uncertainty of the empirical formation probability appears comparable to the discrepancy between calculated values. Conclusions: The results obtained from the present study provide direct evidence for predictive limitations of the existing fusion-evaporation models. It is thus necessary to find other ways to assess such models for the purpose of establishing a more reliable reaction theory, which is expected to guide future experiments on the production of superheavy elements. [ABSTRACT FROM AUTHOR]

Published
2016
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