Vol.11,

In order to carry out the measurement of heavy nuclei in accelerator mass spectrometry, characteristic X-rays of the incident projectile have been explored and used as a method for isobar discrimination. The projectile X-ray combined with AMS technique has been set up in China Institute of Atomic Energy. The measurement of ⁷⁹Se was performed by resorting to the projectile X-ray AMS technique and the detection sensitivity of ⁷⁹Se was improved more than 2 orders of magnitude. The detection limit was about 3.6x10^-9 for ⁷⁹Se/Se.

387

A small size plant for seawater desalination using nuclear heating reactor coupled with MED process was developed by the Institute of Nuclear Energy Technology, Tsinghua University, China. This seawater desalination plant was designed to supply potable water demand to some coastal location or island where both fresh water and energy source are severely lacking. It is also recommended as a demonstration and training facility for seawater desalination using nuclear energy. The design of small size of seawater desalination plant couples two proven technologies: Nuclear Heating Reactor (NHR) and Multi-Effect Destination (MED) process. The NHR design possesses intrinsic and passive safety features, which was demonstrated by the experiences of the project NHR-5. The intermediate circuit and steam circuit were designed as the safety barriers between the NHR reactor and MED desalination system. Within 10~200 MWt of the power range of the heating reactor, the desalination plant could provide 8000 to 150,000 m³/d of high quality potable water. The design concept and parameters, safety features and coupling scheme are presented.

505

The crystallographic and magnetic structures of Er₂Fe₁₅Al₂ and Er₂Fe₁₂Al₅ have been refined in Gaussian peak-shape by Rietveld analysis of Neutron diffrac tion data. The refined results indicated that Er₂Fe₁₅Al₂ compound has Th₂Ni₁₇-type hexagonal structure (space group: P6₃/mmc) and Er₂Fe₁₂Al₅ has Th₂Zn₁₇-type rhombohedral structure (space group:R3¯m). The Al atoms prefer 12j and 12k sites with occupancies 0.21 and 0.13, respectively, in Er₂Fe₁₅Al₂ and prefer 18f, 18h and 6c sites with occupancies 0.35, 0.36 and 0.37, respectively, in Er₂Fe₁₂Al₅. The magnetic moments of all Fe atoms display ferromagnetically arrangement and the moments of Er atoms couple ferrimagnetically to the moments of the Fe atoms. The moments lie in the plane perpendicular to the six-fold axis and exhibit planar magnetic anisotropy in both samples. The values of Tc were given and the neutron refined results coincide with that of the magnetic measurements. The relation between magnetic properties and structures was discussed.

377

571

Inhibition effects, control probabilities and pathology tissue changes of mouse transplanted tumors S₁₈₀ after irradiation with 50 MeV/u ¹²C⁶⁺ ions are reported. Doses of single irradiation were 0.5, 1, 2, 5, 10, 20, 40 Gy, respectively, at a dose rate of 3 Gy/min. Observing time was 24 days. The results show that each group had significant inhibition action on S₁₈₀ tumors and all inhibitory probabilities were more than 90%; the initial time of inducing tumor inhibition effects were within one week in high dose groups (20, 40Gy), and after two weeks in medium dose groups (5. 10 Gy) and low dose groups (0.5, 1, 2Gy); also, inhibitory effects in high dose groups were obviously greater than other groups (p <0.05); tumor control probabilities were different in each group, those in high dose groups (20, 40 Gy) were higher and TCD₅₀ (50% tumor control dose) was 20 Gy; the results for curing tumors are different in different doses; pathology inspection presented here were tumor tissue necrosis and degeneration in each dose group and they depended on doses.

554

An experimental study of high-spin states in ⁷⁹Kr has been performed at the GASP array using the reaction ⁵⁵Mn(³⁰Si, αpn). Nine new states along with 10 new gamma ray transitions were found in the K^π=5/2^- band in ⁷⁹Kr. Three band crossings, associated with the alignments of a πg9/2 pair and a πg9/2 pair and also a high-j 5h_11/2 intrude orbital, were observed at rotational frequency h=0.50, 0.65 and 0.90 MeV, respectively. A cranked shell model analysis has been made to interpret the experimental results.

407

637

Besides the state equation there exists another cubic algebraic equation about μf in the form ofμf3 + pμf + q = 0, which relates parameters, temperature T, chemical potential μf, and net quark number nff (flavor f) for a baryon-rich quark-gluon plasma (QGP). A criterion may be acquired simply according to Cardan formula of the solution of the above equation, which gives naturally a condition: if n≪2πT3/33, one may approximately use the conservation of specific entropy, and then the set of hydrodynamic equation of baryon-rich QGP may be reduced to the set of hydrodynamic equation for baryon-free QGP.

465

The coherent transition-radiation emission from an underdense relativistic beam of electrons, travelling through a dense plasma ripple, was studied. The evolution of this radiation field is described by a set of self-consistent pendulum-wave equations. Analytic calculations of the small-signal gain and numerical computations of the nonlinear saturation of this emission are presented. It is shown that such a device may provide a source of tunable coherent radiation ranging from the microwave to the infrared region.

485

70 MeV-carbon-ion irradiation is used to simulate the radiation swelling induced by neutron irradiation of 3.2×10²² n•cm^-2 in domestically-made 316 austenitic stainless steels modified by a 20%-cold-working and Ti-adding from room temperature to 802℃. The created swelling is microscopically examined by the positron annihilation lifetime technique. A radiation swelling peak is observed at 580℃ and the corresponding void has an average diameter of 0.7nm which is hardly probed by macroscopic methods.

417

Using the particle-rotor model, the energy spectrum and the B(M1)/B(E2) ratio of the negative-parity yrast band in ¹⁵⁵Tb are investigated and compared with the experimental data before and after the band-crossing. It is noted that before and after the band-crossing the moment of inertia of the core is a smooth function of the total angular momentum I and can be described by the ab formula. The yrast band of ¹⁵⁵Tb with negative parity may be triaxially deformed (γ=-13°) before and an axially symmetric shape (γ=0°) after the band-crossing.

383

According to recommended conditions two bio-samples, tea leave and flour, are prepared with different methods: grounding into powder and reducing to ash, then they were analyzed by γ ray spectrometry. Remarkable difference was shown between the measured values of tea samples prepared with these different methods. One of the reasons may be that the method of reducing to ash makes some nuclides lost. Compared with the "non-destructive" method of grounding into powder, the method of reducing to ash can be much more sensible to the loss of some nuclides. The probable reasons are discussed for the varied influences of different preparation methods of tea leave and flour samples.

595