12C6+离子束辐照对小麦种子萌发、幼苗生长及存活的影响

采用12C6+离子束对小麦(Triticum aestivum L)种子进行不同剂量(0、10、20、30、60、120、150和200 Gy)辐照处理,考察种子萌发率、幼苗根长及株高、有丝分裂活动及存活率等生物学特性。结果表明:试验剂量范围内,大多数种子能够正常萌发;低剂量(10 Gy和20 Gy)辐照对幼苗生长具有促进作用,而高剂量辐照则表现出明显的抑制作用;根的生长与分生组织细胞有丝分裂指数密切相关,低剂量时有丝分裂指数略有增加,而高剂量则相反,分裂细胞被选择性阻滞在中期和后期。存活率曲线呈"抛物线"状,半致死剂量(LD50)为55Gy。     

The internal conversion coefficients of the 2+–0+, E2 nuclear transitions in even-even nuclei

Measured values of the internal conversion coefficients of 39 E2 (2⁺–0⁺) transitions in even-even nuclei are listed and averaged in most of the cases where there is more than one result. Comparison with values calculated without interpolation by Band, Listengarten, and Trzhaskovskaya shows only fair agreement but no consistent clustering above or below the theoretical expectations. In 13 out of the 39 cases the experimental error bar does not include the theoretical value. Of the experimental values 21 are greater and 18 less than the calculated results.     

Sputtering of materials by H+, D+, T+ and He+ Ions

The sputtering yields of various materials by H⁺, D⁺, T⁺, He⁺ ions were calculated using the theoretical dependence of sputtering yields on energy and ion mass and taking into account experimental sputtering yield values, whenever available, as measured for H⁺, D⁺, T⁺, He⁺ ions.     

Auger electron spectra in 5.5 MeV/amu Neq+ and Arq+ ion impact on Ne

A study of Ne K Auger spectra induced by 5.5 $\text{MeV}\text{amu}$ Ne³⁺ Ne¹⁰⁺ Ar⁶⁺ and Ar¹⁷⁺ heavy ions on Ne is presented. Some average quantities (the centroid energy of KLL Auger spectra, the average number of L vacancies produced simultaneously with the K vacancy, the effective charge of the projectile in the actual process, the satellite to total intensity ratio) characterising the KLⁿ ionization process have been extracted from these spectra. Relative K-shell ionization cross sections and KLM to KLL cross section ratios have been evaluated. The deduced experimental Z_eff values have been compared with the results of PWBA and BEA calculations. A simple model calculation is made in an attempt to interpret the variation of the probability for the ejection of an L-shell electron (p_L) as a function of $\text{Z}{}_{\mathrm{eff}}\text{v}{}_{\mathrm{p}}$. Some statements regarding individual lines and groups in the Auger spectra are made.     

Adiabatic relativistic rotation-vibration energy levels for HD+, HT+, and DT+

Rotation-vibration energies calculated at the adiabatic level of approximation with the inclusion of relativistic corrections in the potential energy curve are tabulated for HD⁺, HT⁺, and DT⁺ for 0 ≤ v ≤ 8 and 0 ≤ J ≤ 8.     

He+ ion energy loss parameter in thin films of UO2

The stopping cross sections of He⁺ ions in vacuum evaporated films of UO₂ have been measured at incident energies from 0.3 to 2.0 MeV. A procedure has been described for obtaining true stopping cross sections by using thin films having various thicknesses. The energy loss parameter of He⁺ ions was determined using slopes at the origin in relative energy loss vs. thickness curves.     

226Ra irradiation to produce 225Ac and 213Bi in an accelerator-driven system reactor

This study aims to produce ²²⁹Th using an innovative nuclear reactor concept,i.e.,accelerator-driven system(ADS)reactor.Herein,we investigated the feasibility of producing ²²⁹Th from neutron transmutation of ²²⁶Ra to expand the availability of ²²⁵Ac and ²¹³Bi in a simple model of ADS reactor.ADS reactor comprises two zones,i.e.,an inner zone with a fast neutron spectrum and outer zone with thermal neutron spectrum,which is a subcritical core...     

Some characteristics of the crystalline-amorphous threshold pointof 31P+ ion-implanted silicon substrates

During ion implantation a stage can be reached in which a continuous layer within the implanted crystal changes into amorphous material. The change begins when the implanted dose attains a certain threshold value (D_T). In-situ reflectivity (R) versus dose (D) measurements, made during the implantation of ³¹P⁺ into Si single crystal substrates showing that both D_T and the work (W_oT) required to induce the threshold conditions within the implanted crystal increase with the implantation energy are reported. It is also shown that the change in reflectivity ΔR_i, which occurs in the dose range that contains D_T, is a function of E and peaks at 140 keV, the energy at which the damaged layer becomes buried. The ratio D_A/D_T is found to be a decreasing function of E     

Observation of a partially-ordered void lattice in aluminium irradiated with 400 keV Al+ ions

Transmission electron microscopy observations of voids formed in aluminium during irradiation at 50°C and 75°C with 400 keV Al⁺ ions, have shown that partially-ordered void arrays are often present. These arrays occur in high-purity annealed aluminium, which has been implanted with 10^?4 atom/atom helium before ion irradiation. The void concentration is found to be $\text{～3 × 10}{}^{16}\text{/ cm}{}^3$, and the void lattice parameter ～ 700 Å. The ratio of void lattice parameter to void radius is ～ 12. Ordered void lattices have been observed frequently in irradiated body-centred cubic metals but the only previous observation for a face-centred cubic metal was in nickel. Theoretical predictions of void lattices in metals are discussed and related to the observations reported herein.     

The Elliptic Flow of Multi-Strange Hadrons in[SNN]1/2= 200 GeV Au + Au Collisions at STAR

Azimuthal anisotropy, especially for the multi-strange hadrons, is expected to be sensitive to the dynamical evolution in the early stage of high energy nuclear collisions. In this paper we present the latest results of multi-strange hadron elliptic flow in Au + Au collisions at[S_NN]^1/2= 200 GeV from the STAR experiment at RHIC. The number-of-quark scaling is evidenced with φ（s） and （sss） with highly statistical data, which shows strange quark collectivity at RHIC. The ν2 of φ meson is found to be consistent with that of proton within statistical error bars at p T<1 GeV/c.     

Electron impact ionization of N4+ and N5+

A new crossed beams apparatus for measuring absolute electron impact ionization cross-sections of multiply charged ions is described. First measurements are also reported which deal with N⁴⁺ and N⁵⁺. The results are in good agreements with those previously obtained by the Oak Ridge group. For N⁵⁺ a non-negligible signal is observed below the ground state ionization threshold. It is attributed to the presence of ions in metastable states. From the semi-empirical Lotz formula, the population of ions in those states is estimated to be approximately 3%.     

Populations of np terms in deuterium atoms emergent from carbon foils bombarded with D+, D2+ and D3+ ions

We have measured relative beam-foil populations of 2p, 3p, and 4p terms in D⁰ as a function of the projectile energy $\text{(20 ?}\text{E}\text{M}\text{? 500}\text{keV}\text{amu}\text{)}$ for D⁺, D₂⁺, and D₃⁺ ions impinging on carbon foils of various thicknesses (? 2–20 $\text{μg}\text{cm}{}^2$).With D⁺ projectiles, the np populations reach their equilibrium values even in the thinnest foils used. We compare the dependence on energy of these populations to the equilibrium neutral fraction variation for hydrogen (deuterium) beams emerging from a carbon foil and deduce some information concerning beam-foil populations.When molecular projectiles pass through very thin foils, well known molecular effects appear which depend on the dwell time, t, i.e., the time spent by the projectile in the foil. In this work we consider only the long-dwell-time region t > 2 × 10^?15s. We study the variation of R_α = I^molec/I^atom (I^molec and I^atom are the Ly-α intensities per incident deuteron (proton) observed with molecular and atomic projectiles of the same velocity, respectively) with the projectile energy per nucleon ($\text{E}\text{M}$) and the thickness (T) of the foil. For a foil of given thickness, R_α increases with $\text{E}\text{M>}$ and reaches a saturation value R_∞ which decreases when T increases. These results, in agreement with our previous measurements using hydrogen projectiles, indicate that t is not the only parameter relevant to molecular effects. Comparisons are reported between $\text{R>}{}_{\mathrm{\alpha }}\text{(E}\text{M>}$) values obtained (a) with H₂⁺ and D₂⁺ projectiles and (b) with D₂⁺ and D₃⁺ projectiles, using foils of various given thicknesses. Ratios $\text{R}{}_{\mathrm{\beta }}\text{(E}\text{M}$) and $\text{R}{}_{\mathrm{\gamma }}\text{(E}\text{M}$) are also measured using Ly-β and Ly-γ radiations and compared to $\text{R}{}_{\mathrm{\alpha }}\text{(E}\text{M}$) values. An interpretation for some of our results is proposed.     

Cross sections for K-shell ionization by 1H, 2H, 3He,and 4He ion impact

Cross section for K-shell ionization derived from experimental measurements with the light ions ¹H, ²H, ³He, and ⁴He are tabulated according to projectile energy and target atomic number.     

Phase changes of the ZrO2-12wt%Y2O3 film with Ar+ irradiation

The zirconia containing 12wt%Y₂O₃ thin films deposited by r.f. magnetron sputtering at 25℃ or 400℃, and then bombarded with Ar⁺ beam at room temperature were characterized with XRD before and after Ar⁺ bombardment. It is found that a series of phases formation and transformation happened, among them the mostimportant event is that T' phase appeared after Ar⁺ irradiation andthe content of the T' phase increased with the increase of Ar⁺ iondoses from 5×10¹⁵ to 6×10¹⁶ ions cm^-2.     

Studies of 1s2s 3S-1s2p 3P transitions in helium-like Ne8+ recoil ions using photographic spectroscopy

This work describes the application of the technique of photographic VUV spectroscopy to accurate measurement of the wavelength of the theoretically interesting 1s2s ³S₁-1s2p ³P₂ transition in helium-like Ne⁸⁺ in a recoil ion source. Good resolution is obtained, and a preliminary value of 124.815±0.002 nm is found for the wavelength.     

4.8 m3外冷式隔板冷凝器在UF6生产过程中的应用研究

研究分析了4.8m3外冷式隔板冷凝器在成品混合气中的UF6捕集、固态UF6液化、液相UF6转移等单元操作过程中各种影响因素的作用规律,探讨了其在UF6生产过程中的使用效果。研究结果表明4.8m3外冷式隔板冷凝器具有安全性能好、UF6冷凝装填量大、耗能低的特点,适于立式炉氟化反应器、卧式炉氟化反应器成品混合气的收集。该冷凝器的结构简单、运行中性能稳定、连续运行能力强、操作方便、易于控制和调节。     

CACPPA的99Tcm标记及其动物实验研究

在pH8.5～9.5的水溶液中,采用氯化亚锡还原法制备     

氘团簇离子(d3+)固体与相互作用过程中的团簇行为研究

讨论了由三个氘原子组成的氘团簇离子(d