STATUS AND PROSPECTS OF HIRFL EXPERIMENTS ON NUCLEAR PHYSICS

HIRFL is an accelerator complex consisting of 3 accelerators, 2 radioactive beams lines, 1 storage rings and a number of experimental setups. The research activities at HIRFL cover the fields of radio-biology, material science, atomic physics, and nuclear physics. This report mainly concentrates on the experiments of nuclear physics with the existing and planned experimental setups such as SHANS, RIBLL1, ETF, CSRe, PISA and HPLUS at HIRFL.

CONSTRAINTS ON THE DENSITY DEPENDENCE OF THE SYMMETRY ENERGY

Collisions involving Sn-112 and Sn-124 nuclei have been calculated with the ImQMD transport model in order to place constraints on the density dependences of the nuclear symmetry energy. Consistent constraints on the symmetry energy at sub-saturation density have been obtained by comparing these transport calculations to measurements of isospin diffusion and to the ratios of neutron and proton spectra. New isospin diffusion results from E/A = 35 MeV are also presented.

In situ electrochemical SERS studies on electrodeposition of aniline on 4-ATP/Au surface

The electrochemical polymerization of 0.01 M aniline in 1 M H2SO4 aqueous solution on roughened Au surface modified with a self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) has been investigated by in situ electrochemical surface-enhanced Raman scattering spectroscopy (SERS). The repeat units and possible structures of the electrodeposited polyaniline (PANI) film were proposed; i.e., aniline monomer is coupled in head-to-tail predominately at the C-4 of aniline and amine of 4-ATP, and the thin PANI film is orientated vertically to substrate surface. Simultaneous Raman spectra during potential scanning indicate clearly that the ultrathin PANI film (in initial growth of the film) consists of semiquinone radical cation (IP+), para-disubstituted benzene (IP and IP+) and quinine diimine (NP) while it is oxidized, and without quinine diimine and semiquinone radical cation while reduced. Meanwhile, the results confirm that 4-ATP monolayer shows a strong promotion on the electrodeposition of aniline monomer, and a possible polymerization mechanism was proposed.

Effects of SBS addition and temperature on 3D siliceous mesostructured cellular foam

Siliceous mesostructured cellular foam with three-dimensional (3D) wormhole structure (MSU-type) is prepared by using triblock copolymer (poly(styrene-b-butadiene-b- styrene), SBS) with both hydrophobic head and tail group as template in strong acid condition via microemulsion method. The effects of SBS addition and temperature on the morphology and physicochemical properties, such as pore diameters, surface areas and pore volumes of the materials have been investigated by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM) and nitrogen adsorption-desorption analysis. The results show that the pore volumes, pore sizes and specific surface areas depend strongly on the SBS amount and forming micelles temperature. Moreover, the materials obtained with high wall thickness exhibit a relatively good thermal stability.

Preparation and luminescence properties of LB films based on 4-hexadecyloxybenzoic terbium

LB films of 4-hexadecyloxybenzoic-terbium by using the subphase containing Tb3+ were prepared. The monolayer behavior of 4-hexadecyloxybenzoic acid (HOBA) on the subphase containing rare earth ions was studied. IR and UV spectra show that the rare earth ions were bound to carboxylic acid head groups and the coordination took place between the polar head group and the rare earth ions. The luminescence spectra show that the LB films have the fine luminescence properties, and the LB films emit strong luminescence under UV light irradiation.

Effect of LB monolayers on the mixed crystals of Lead and barium sulfate

The effect of LB monolayers on the mixed crystal was investigated by using X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), and Inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results show that LB monolayer has selectivity for the different nucleation ions with equal charge numbers and about the same ion radius. The selectivity is dependent on the head groups of monolayer. The monolayer and the doped ions have also an effect on the crystal morphology. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Synthesis, electrical properties and crystal structure of a new radical-ion salt based on pi-extended bis(TTF) and a Keggin heteropolymolybdate

By electrocrystallization of 2,6-[4,5-bis(n-butylsulfanyl)-1,3-dithiol-2-ylidene]-4,8-bis(6-iodo-n-hexyloxy)-1,3,5,7-tetrathia-s-indacene (BHBDTI) and [NBu4](4)[SiMo12O40] in the mixed solvent CHCl2CH2Cl and CH3CN, the new radical-ion salt [C42H60Cl2O2S12](2)[SiMo12O40] was prepared. It was characterized by means of IR and ESR spectroscopy and X-ray diffraction. In the crystal structure, organic radical dications and silicomolybdate anions are alternatively arranged along the a axis to form a 1-D conducting layer. The organic layer consists of two isolated groups of BHBDTI divided by the (011) plane without short interatomic contacts. However, in each group, BHBDTI molecules associate with each other in a head to tail manner running along the [011] direction and face-to-face overlapping with a relative shift by approximately one TTF subunit along the long axis of the molecule and a slight shift along the short axis of the molecule with significantly short S ... S contacts. The room-temperature d.c. conductivity determined by the two-probe method is 10(-4) S cm(-1), suggesting that the compound is a semiconductor.

Electrochemical studies of lipophilic ion transport through BLM. The influence of sterols on its transport

Cyclic voltammetry was employed to study the influence of sterols on the lipophilic ion transport through the BLM. The mole fraction of the sterols (cholesterol, oxidized cholesterol). as referred to total lipid, was varied in a range of 0-0.8. Data demonstrate that a thin-layer model is suitable to this BLM system. By this model, the number of charges transported per lipophilic ion, the concentration of the ion in the membrane bulk phase and the aqueous/membrane phase partition coefficient could be calculated. These parameters proved that sterols had an obvious influence on the lipophilic ion transport. Cholesterol had a stronger influence on the ion transport than oxidized cholesterol. Its incorporation into egg lecithin membranes increased the partition coefficient beta of the ion up to more than 3-fold. Yet, oxidized cholesterol incorporated into egg lecithin membranes only increased the beta up to less than 2-fold, and the beta had no great variation at different oxidized cholesterol mole fractions. The higher beta obtained was partly due to the trace amount of solvent existing in the core of the lipid bilayers. At the different sterol mole fractions, combining the change of beta with the change of peak current, we also concluded that sterols had somewhat inhibiting effect on the ion transport at the higher sterols mole fraction (>0.4). These results are explained in terms of the possible change of dipole potential of the membrane produced by sterols and the decrease of the membrane fluidity caused by the condensation effect of sterols and the thinning effect caused by sterols. The substituting group (in the oxidized cholesterol) had some inhibiting effects on the ion transport at higher mole fractions (oxidized cholesterol mole fraction >0.4).

2D NMR and FT-Raman spectroscopic studies on the interaction of lanthanide ions and Ln-DTPA with phospholipid bilayers

The interactions of lanthanide ions and the Ln-DTPA (DTPA = diethylenetriaminepentaacetate) complex with di palmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine (DPPE) bilayers are studied by 2D NOESY and FT-Raman spectroscopy. Proton NMR spectroscopic results show that lanthanide ions combine with phosphate groups in the polar region of the outer layer of DPPC liposomes, leading to the separation in chemical shift of the proton signal of N(CH3)(3) The conformational change of the O-C-C-N+ backbone from the gauche conformer to the trans one is not found; i.e., the orientation of the polar headgroup is still parallel to the surface of the bilayers. The Ln-DTPA complex at low concentration in a pH 7.4 solution localizes far away from bilayers and thereby has little effect on the structure of bilayers. The FT-Raman spectroscopic results indicate that lanthanide ions affect strongly the fluidity of acyl chains of DPPE bilayers while the Ln-DTPA complex affects it slightly.

NMR and FT-Raman studies on the interaction of lanthanide ions with sphingomyelin bilayers

The interactions of lanthanide ions with sphingomyelin bilayers have been studied by using 2D NOESY spectroscopy and FT-Raman spectroscopy methods. The results indicate that lanthanide ions, as well as divalent calcium, combine mainly to the phosphate group in the polar headgroup and do not change the conformation of O-C-C-N+ backbone in the choline group of sphingomyelin bilayers. The polar headgroup is still extending parallel to the bilayer surface and O-C-C-N+ group is still in its gauche conformer.

Effects of delayed first feeding on growth and survival of rock bream Oplegnathus fasciatus larvae

The effects of the timing of first feeding (0, 1 and 2 days after yolk exhaustion) and starvation on the point-of-no-return (PNR), survival and growth of laboratory-reared rock bream larvae were studied under controlled conditions. Larvae began to feed exogenously at 3 days after hatching (dah) and reached PNR on 54 h after yolk exhaustion at 22 +/- 1.5 degrees C. Larvae growth was significantly affected by the time of first exogenous feeding. The growth of 0 day delayed first feeding larvae was obviously faster than those of the other delayed first feeding larvae (P<0.05) whether at 7 dab (SL=3.40 mm, SGR=5.7, CV=4.0) or at 15 dah (SL=4.85 mm, SGR=6.1, CV=8.2) with a more uniform size distribution. Survival of 0 day delayed first feeding larvae and I day delayed first feeding larvae was 13% and 8% at the end of experiment, respectively, while no larvae survived up to 7 dah for 2 days delayed first feeding larvae and unfed larvae. Food resulted in a progressive deterioration of the larval digestive system and atrophy of skeletal muscle fibre. The ratios of head length to SL (standard length), body height to SL and eye diameter to SL were the most sensitive morphometric indices to detect the effects of fasting on larval condition. Present results showed that the combination of morphological and morphometric variables could be used to evaluate the nutritional condition of rock bream larvae. In order to avoid the potential mortality and gain better development, survival and growth in industrial production, the rock bream larvae must establish successful first feeding within 2 days after yolk exhaustion. (C) 2008 Elsevier B.V. All rights reserved.

The effect of supplementary feeds on the bodyweight of yaks in cold season

The present study was conducted to determine the effects of supplementary feeds, oat hay (OH), highland barley straw (HBS) and multi-nutrient blocks supplementation (UMMB) on reducing liveweight losses of both yak cows and calves grazed on low quality pastures during cold season. The trials of OH and HBS supplementation were conducted by using completely random design on 104 yak cows between 6 and 12 years of age as the following treatments: pure grazing (41 animals, body weight 230 67 kg) as control (CK); grazing+1.5 kg DM of OH per head daily (30 animals, body weight 216 28 kg); gazing. 1.5 kg DM of HBS per head daily (33 animals, body weight 221 34 kg). The trial of UMMB was conducted on three types of yaks, 1-year calves (8-12 months old, body weight 61.1 6.9 kg), 2-year calves (18-24 months old, 98.0 11.3 kg) and yak cows (164.5 27.1 (S.D.) kg) with 20 animals in control group (CK) and 20 animals in supplement group for each type by using completely random design as the following treatments: pure grazing for CK group; grazing+ 150, 250 and 500 g UMMB per day averagely for 1-year calf, 2-year calf and cow at night. The results indicate that the animals supplemented with oat hay received body weight gain (32 20.7 g day(-1)), while those supplemented with highland barley straw still suffered from body weight loss (-56.7 39.3 a day(-1)); UMMB supplementation can decrease the body weight loss by 109.7%, 86.6% and 63.4% for the 1-year calves, 2-year calves and yak cows, respectively, as compared with pure grazing. Around US$1.60 output can be achieved on the basis of US$1 input for UMMB supplementation in the farming systems of the 1-year calves, 2-year calves and yak cows, while US$1 input can produce US$1.55 and 1.14 output for OH and FIBS supplementations, respectively, in yak cows' farming system. It can be preliminary concluded that UMMB supplementation was the most economic way to alleviate body weight loss of grazing yaks over cold season, and the higher productive returns were obtained from OH supplementation for grazing yak cows during winter/spring months. © 2004 Elsevier B.V All rights reserved.

Effect of urea multinutritional molasses block supplementation on liveweight change of yak calves and productive and reproductive performances of yak cows

Using three different types of yaks, 30 head of 1-yr-old calves (liveweight 60.7 +/- 6.3 kg), 30 head of 2-yr-old calves (97.7 +/- 10.2 kg) and 30 head of yak cows (160.2 +/- 15.1 kg) were randomly selected from the same yak herds. Each type of yak herd was divided into control (C) and trial (T) groups using a completely randomized design, with 10 and 20 animals in the C and T groups, respectively. The animals in the C group were grazed on natural rangeland, and the animals in the T group were supplemented with urea multinutritional molasses blocks (UMMB), together with grazing on natural rangeland from January to May of 1998. The objective was to determine the effect of UMMB on productive performance of yak calves and yak cows in the cold season. Live weight loss of 1-yr-old calves, 2-yr-old calves and yak cows was reduced by 1.2, 8.3 and 7.9 kg after UMMB supplementation (P < 0.01). The 1-yr-old calves gained the most in the first month of supplementation, but the 2-yr-old calves and yak cows gained the most both in the first and last supplementation months. Daily milk yield of yak cows increased by 0.21 kg d(-1) when the lactating animals were supplemented with UMMB (P < 0.01), although there was no effect (P < 0.01) of UMMB supplementation on hair and downy hair production. Supplementation with UMMB also improved reproductive performance of yak cows, with 8.8 and 30.9% increments in pregnancy rate and newborn weight, respectively. We conclude that the benefit of UMMB supplementation the 1-yr-old calves was not economical, with only 0.3:1 output to input ratio, but supplementation of the 2-yr-old calves and yak cows may be economical, with 1.8:1 and 1.4:1 output to input ratios, respectively.