Recombinant expression in Escherichia coli of human cyclic nucleotide phosphodiesterase 41132 (hPDE4B2) fused to maltose-binding-protein (MBP-hPDE4B2) was investigated. hPDE4B2 DNA amplified via nested RT-PCR with total RNAs from U937 cells was ligated with pMAL-p2x. After induction at 18 degrees C for 16h, soluble MBP-hPDE4B2 was produced in E. coli. MBP-hPDE4B2 after amylose-resin chromatography showed 35% homogeneity, and its Michaelis-Menten constant was 10 +/- 2 mu M (n = 3). Rolipram had a dissociation constant of 9 +/- 2 nM (n = 2), and zinc ion was a potent inhibitor. Hence, MBP-hPDE4B2 was expressed in E. coli as a soluble active protein.

Objective To characterize an extracellular uricase from Bacillus fastidious(ATCC 26904) and to evaluate its efficiency for direct kinetic assay of serum uric acid.Methods The extracellular uricase from Bacillus fastidious(ATCC 26904) was purified by DEAE-cellulose chromatography.This uricase was used for serum uric acid assay by predicting the background absorbance of uricase reaction solution with the integrated method.Results This uricase contained one polypeptide of 34.7 kD and its Km was(0.22±0.01) mmol/L(n=11).The inhibition constant of xanthine was(36±3) μmol/L(n=4).With this uricase,residual uric acid at the last datum under analysis below one-third of the first datum under analysis enabled reliable estimation of background absorbance.By directly measuring the absorbance before uricase reaction,this direct kinetic uricase method exhibited resistance to 15 μmol/L xanthine,the variation of enzyme activity and other common interferences.It gave linear response to uric acid concentration from 1 to 50 μmol/L in reaction solution with 0.025 U/ml uricase to monitor reaction within 5 min.Uric acid concentration in clinic sera by the direct kinetic uricase method(Ck) was closely correlated to that by the equilibrium method through peroxidase-coupled assay of hydrogen peroxide(Ce)(Ck=-0.008+1.046Ce,r=0.996,n=206),but Bland-Altman analysis indicated inconsistency between Ck and Ce.Conclusion This extracellualr uricase was desirable as a tool enzyme for serum uric acid assay by the direct kinetic uricase method.

Thin film synthesis and applications using ion beam technology at Ion Beam Laboratory,Chinese Academy of Sciences,were reviewed.The results of surface modification of materials prepared by Ion Beam Assisted Deposition (IBAD), Filtered Arc Deposition (FAD) and Silicon－ On－ Insulator (SOI) by ion implantation were reported. The industrial and military applications of ion beam technology were dicussed as well.

报道了用叠加能量Ｓｉ＋、Ｎ＋共注入ＳｉＯ２薄膜研究硅基发光材料。Ｓｉ＋、Ｎ＋先后注入ＳｉＯ２薄膜，并在衬底中重叠。样品退火后在紫外光激发下，可以观察到很强的紫外（～３４０ｎｍ）和紫色（～４２７ｎｍ）光致发光（ＰＬ）。还研究了光致发光激发（ＰＬＥ）谱并对发光机制进行了探讨。

The role of thermal effects in primary damage production during ion implantation, i.e., a so-called micro-and macrotemperature, will be outlined. It is suggested that a strict control of thermal conditions around the cascade(s) can be a key factor in implantation technology, especially, when properties of layers implanted in different machines are compared. The role of hot implantation as an annealing concept will be demonstrated for the case of implantation with bi-molecular ions.

TiN films have been synthesized by ion beam assisted deposition employing xenon ions with an energy of 40 keV. The formed TiN films were investigated systematically in respect of surface morphology, composition, structure and mechanical properties. Then, they were applied to surface protection of scoring dies. Atomic force microscopy and interferometric observation showed that the TiN film is relatively smooth. Rutherford backscattering spectroscopy analysis indicated that few xenon atoms are retained in the film. It was found by transmission electron microscopy and X-ray diffraction experiments that the formed TiN is a nanocrystal (< 10 nm) film and exhibits slightly (200) preferred orientation. An ultra low load microhardness indentor system was used to examine the plastic property of the film and a hardness of 2300 kgf mm−2 was calculated from the measured data. Scratch tests showed that the adhesion of TiN film deposited by ion beam assisted deposition at ambient temperature is superior to that of high temperature physical vapour deposited (PVD) TiN film. Both a pin-on-dick tribotest and SRV wear test revealed that the wear resistance of the specimen can be greatly improved by TiN coating. A five times increase of service life of different scoring dies could be obtained by protection of TiN coating.

Nano-TiN films produced by Xe+ ion beam enhanced deposition were studied by the slow positron annihilation technique. The Doppler broadening of the annihilation γ-ray energy spectra were characterized by the line-shape parameter S. The results showed that there are two types of defect. One is related to interfaces and the other is related to nano void. Their concentrations and sizes are strongly dependent upon the implanting energy and dosage.

The simulations were performed to study the behavior of atoms in the layers at surface or near surface of Si(001) by using the two-dimensional pair correlation functions. The atoms interact via a potential developed by Stillinger and Weber, which includes both the two-body and three-body contributions. The results showed that the atoms in deep layers still remain in their (001) atomic plane lattice sites, whereas the atoms in the surface layer are rearranged, and the majority of them forms bonding with bond length of 0.24 nm. Besides, the relaxation problems were also discussed.

Molecular dynamics simulations were performed for 1-100eV particle bombardments of Si(001)-2×1 surface. The two dimensional pair correlation functions were obtained to investigate the arrangement of surface atoms after such bombardments. The results show that 10eV and 100eV bombardments had the some effects on the behaviour of surface atoms. On one hand, 10eV and 100eV bombardments improved the mobility of surface atoms and produced more dimers. On the other hand, they increased the disordering of surface atom's arrangement and made the surface tend to be amorphous.

Molecular dynamics simulations were performed to obtain the two-dimensional pair correlation functions of Si(001) surface and deeper layers. The atoms interact via a potential developed by Stillinger and Weber, which includes both two-body and three-body contributions. The results show that the atoms in deeper layers still remain at their(001) atomic plane lattice sites, while the atoms in surface layer are rearranged, and a large part of them form bonding and the bond length is 0.2, 40nm. The relaxation problems have also been discussed.

本文对用多种离子束技术进行表面处理的金属间化合物Ni 3 Al（0.1B）进行耐腐蚀和抗氧化试验.结果表明,离子注入、离子束混合和离子束增强沉积对提高金属间化合物Ni 3 Al（0.1B）在水溶液中的耐腐蚀性能和在纯氧中的高温抗氧化行为都有很好的效果.

Ion implantation, ion beam mixing, and ion beam enhanced deposition (IBED) were employed to improve oxidation resistance of intermetallic compound Ni3Al(0.1B) in pure flowing oxygen at temperature of 1100 K. X-ray diffraction and scanning electron microscopy were used to examine the composition and structure of the scales after oxidation. Improved resistance to oxidation of Ni3Al(0.1B) was observed in Ta+-implanted, ion beam mixed Si layers, and IBED films coated specimens. The possible mechanisms for these effects were discussed.

<span id="ChDivSummary" name="ChDivSummary" class="abstract-text">本文提出一个合成TiN硬质薄膜的新方法,在氮气氛中,电子束蒸发沉积Ti的同时,用40keV的氙离子束对其进行轰击而合成TiN薄膜,该方法优于PVD和CVD之处在于合成温度低,薄膜与基体结合力强,其临界载荷达4.2kg,Knoop硬度达2200kg/mm²,具有良好的耐磨损性能,报道了所合成的TiN薄膜在工业上应用的一些结果。</span>

Bombardment of evaporated titanium films with energetic Xe+ ions deposition in nitrogen atmosphere has a marked effect on film properties. In comparison with evaporated titanium films, the Xe+ ion-bombarded films contained more nitrogen and thus TiN films, instead of titanium films, have been formed. There were very small amounts of oxygen and xenon retained in the film. We also observed compressive stress in the Xe+-ion-bombarded films, whereas the evaporated films were nearly stressless. The critical load, determined by the scratch test, to damage the Xe+-ion-bombarded TiN films on steel and silicon substrates was twice that for evaporated films, which indicated that the adhesion of the film to the substrates was greatly promoted by Xe+ ion bombardment. The hardness of the TiN films formed by Xe+ ion bombardment reached 2200 kgf mm−2, which was not only much higher than that of the evaporated films, but also higher than those of films formed by bombardment with N+ ions in the same condition. The results are explained from the viewpoint of the difference in energy deposited in the films by incident ions.

本文研究了单晶硅中磷分子离子（P 2 + ）注入相对于磷原子离子（P + ）注入的损伤增强效应,系统分析了这种损伤增强效应与注入剂量、能量、靶温的关系以及注入后退火的特征,利用我们提出的离子注入时分子离子与靶原子的多体碰撞模型对其物理机制进行了讨论.

A new method for preparation of hard TiN films has been developed by electron beam evaporation--deposition of Ti and bombardment with tens keV Xe~+ ion beam in a N_2 gas environment. The TiN film, prepared by Xe~+ ion beam enhanced deposition, is superior to PVD and CVD ones in respects of improved adhension to substrate and low preparing temperature. It exhibited good wear resistance and high Knoop hardness up to 2200 kg / mm~2. Some indus- trial applications have been reported.

The electrical properties and characteristics of photoluminescence (PL) at 11K for InP implanted with Si+ at 200℃ have been studied. It has been found that the sheet electron concentration in Si+ simply implanted sample tends to a saturation level with increasing the Si+ dose, while that in Si++P+ dually implanted sample increases greatly. The 11K PL spectra reveals that there exists Sip-Vp complex in Si+ implanted InP, which can be inhibited by co-implanting P+. The mechanism of improved electrical properties by Si++P+ dual implants is, also discussed.