We study theoretically the fragmentation of the helium dimer, 4He2, into singly charged ions in collisions with relativistic highly charged projectiles. We discuss the main mechanisms driving this process with the focus on the fragmentation caused by direct ionization of both atomic sites of the dimer in a single collision with the projectile. This direct mechanism dominates the He2 ??? He+ + He+ breakup events with the kinetic energies of the emerging ionic fragments below 4???5 eV. We explore the energy and angular distributions of the He+ ions produced in collisions with 1 and 7 GeV/u U92+ projectiles and show that their shape is significantly affected by relativistic and higher-order effects in the interaction between the projectile and the dimer. We also show that the shape of the energy spectrum is quite sensitive to the binding energy of the He2 dimer, which can be exploited for its precise determination. The contribution of the direct mechanism to the total cross section for the He2 fragmentation by 1 and 7 GeV/u U92+ was calculated to be 3.65 Mb and 2.4 Mb, respectively, representing roughly half of this cross section.

We study theoretically the fragmentation of the helium dimer, $^{4}\mathrm{He}_{2}$, into singly charged ions in collisions with relativistic highly charged projectiles. We discuss the main mechanisms driving this process with the focus on the fragmentation caused by direct ionization of both atomic sites of the dimer in a single collision with the projectile. This direct mechanism dominates the ${\mathrm{He}}_{2}\ensuremath{\rightarrow}{\mathrm{He}}^{+}+{\mathrm{He}}^{+}$ breakup events with the kinetic energies of the emerging ionic fragments below 4--5 eV. We explore the energy and angular distributions of the ${\mathrm{He}}^{+}$ ions produced in collisions with 1 and 7 GeV/u ${\mathrm{U}}^{92+}$ projectiles and show that their shape is significantly affected by relativistic and higher-order effects in the interaction between the projectile and the dimer. We also show that the shape of the energy spectrum is quite sensitive to the binding energy of the ${\mathrm{He}}_{2}$ dimer, which can be exploited for its precise determination. The contribution of the direct mechanism to the total cross section for the ${\mathrm{He}}_{2}$ fragmentation by 1 and 7 GeV/u ${\mathrm{U}}^{92+}$ was calculated to be 3.65 Mb and $2.4\phantom{\rule{0.16em}{0ex}}\mathrm{Mb}$, respectively, representing roughly half of this cross section.

We consider photo ionization of an atom which, due to passing through a diffraction grating, is prepared in a multi-site state possessing a periodic space structure with alternating maxima and minima. It has been found that this process qualitatively differs from photo ionization of a 'normal' atom. In particular, the spectra of emitted electrons and recoil ions in this process display clear one- and two-particle interference effects. Moreover, there are also striking differences between the momentum distributions of these particles, which no longer mirror each other. The origin of all these features is discussed in detail. It is also shown that the information about the diffraction grating, which is encoded in the multi-site state of the atom, can be fully decoded by exploring the spectra of recoil ions whereas the photo-electron spectra contain this information only partially.

On the basis of investigating the behaviour of migration and accumulation of the oxides in a coelectrolytic deposited layer in the process of aluminizing, some studies on the influences of aluminizing conditions, size of oxide particles and microstructure of substrate were carried out. A mechanism about "drawing effect" for nano-size oxide particles resulted from NiAl/Ni moving interface was suggested.

The ion implantation of 2 x 10(16), 5 x 10(16) and 1 x 10(17) Ce+/cm(2) to Ni20Cr alloy can significantly decrease its oxidation rate at 1000 degrees C and 1100 degrees C, and improve the adhesion of oxide scales. The influence of Ce ion implantation on the binding energy of alloying elements has been studied by Ion Microprobe Miss Analyzer (IMMA). The binding energy of Cr+ in the implanted layer of the alloy decreases, which promotes the protective Cr2O3 to form quickly during the initial oxidation stage. However the binding energies of Cr+ and Ni+ in the oxide scales increase, and the outward diffusion of Cr3+ and Ni2+ through the oxide scales is suppressed. This result may be related to changing the concentration of defects due to Ce ion implantation. After cyclic oxidation at 1000 degrees C for 270 times, the beneficial effect of Ce on the resistance to oxidation is still obvious.

The behaviours of oxidation of several NiAl - base coatings containing CeO 2 or not were investigated at 900��C and 1000��C, and the microstructures of the coatings oxidized or not, morphologies of the scales and the scale/substrate interface were observed. On the basis of knowledge of the effect of CeO 2 on the oxidation kinetics for Al 2O 3 scale and the degradation of NiAl - base coating, the mechanism about improvement of oxidation resistance of the coating by CeO 2 addition was proposed. KEY WORDS CeO 2, Ni-Al coating, Oxidation resistance.

１２７３Ｋ循环氧化１００ｈ的实验结果表明，金属Ｎｉ表面沉积一层Ｎｉ－Ｌａ２Ｏ３复合镀层（厚为３０μｍ）后，抗循环氧化性能比金属Ｎｉ和表面沉积相同厚度Ｎｉ镀层的金属Ｎｉ有极大改善。Ｎｉ及其单镀Ｎｉ后，氧化速率快，氧化皮严重开裂；沉积复合镀层后，氧化速率显著降低，表面氧化层晶粒明显细化，氧化皮下发生开裂电子探针（ＥＰＭＡ）观测发现，Ｌａ２Ｏ３分布在氧化层（５０μｍ厚）的上表层（３１μｍ厚）中。高分辨电子显微镜（ＨＲＥＭ）发现复合镀层中分布着尺寸＜５ｎｍ的Ｌａ２Ｏ３纳米颗粒，据此提出，氧化时，由于小尺寸的Ｌａ２Ｏ３纳米颗粒易部分溶解，成为产生并在氧化层晶界偏聚的Ｌａ３＋的＂储存池＂。Ｌａ３＋在ＮｉＯ晶界偏聚，阻止了Ｎｉ２＋的短路扩散，改善了复合镀层氧化层的生长机制和力学性质．

<span id="ChDivSummary" name="ChDivSummary" class="abstract-text">在研究１０００及１１００℃下含弥散ＣｅＯ_２的ＮｉＡｌ基表面α─Ａｌ_２Ｏ_３氧化膜初期生长的微观形貌及化学组成的基础上，分析了弥散氧化物质点对氧化初期表层扩散通量的影响，解析出了氧化物质点对表层元素扩散通量的贡献项，进而研究了氧化温度、弥散氧化物质点的尺寸、含量及分布等因素对弥散氧化物质点促进Ａｌ_２Ｏ_３形成的影响，并解释了突出颗粒状生长等实验结果。同时，探讨了弥散氧化物质点促进保护性氧化膜形核和增强氧化膜再生能力的机制。</span>

The effect of CeO2 on atomic connection energies in the Al2O3-type scale formed at 1100��C isothermally and at the scale/substrate interface, were studied by a novel SIMS technique of measuring the curves of Al, Ni secondary ion density vs resistance voltage. Based on the results of the increase in the atomic connection energies by CeO2 addition, the mechanism about the effect of CeO2 on the oxidation kinetics of Al2O3-type scale were analyzed.

ＭａＸｉｎ－Ｑｉｎｇ；（马信清）；ＬｉＭｅｉ－Ｓｈｕａｎ；（李美栓）；ＬｉＴｉｅ－Ｆａｎ；（李铁藩）（ＩｎｓｔｉｔｕｌｅｏｆＣｏｒｒｏｓｉｏｎａｎｄＰｒｏｔｅｃｔｉｏｎｏｆＭｅｔａｌｓ，ＣｏｒｒｏｓｉｏｎＳｃｉｅｎｃｅＬａｂｏｒａｔｏｒｙ，Ａｃａｄｅ...

<span id="ChDivSummary" name="ChDivSummary" class="abstract-text">注入剂量为２×１０１６，５×１０１６，１×１０１７／ｃｍ２的Ｃｅ＋，使Ｎｉ２０Ｃｒ合金在１０００和１１００℃下的氧化速率显著降低．氧化膜致密、完整、粘附性好．利用离子探针分析技术测量了注Ｃｅ＋后，合金元素在合金表面及１１００℃形成的氧化膜内结合能差．注Ｃｅ＋后降低了合金表面Ｃｒ＋的结合能，有利于其向外扩散从而快速成膜；增大了膜内Ｃｒ＋和Ｎｉ＋的结合能，对这些离子在膜内的扩散起阻碍作用．因此，Ｃｅ＋的注入能改善合金的抗氧化性能．此外，在１０００℃循环氧化２７０次后，氧化膜部分剥落，Ｃｅ改善合金抗氧化性能仍十分显著．</span>