[en] The theory, the performance and the application of resistive anodes for one-dimensional position-sensitive detector are talked about. The one-dimensional resistive anode with the position resolution better than 200 μm and the linear coefficient between the energy and position γ 0.99962138 have been achieved. They work very well in the instrument of Electron Momentum Spectroscopy (EMS)

[en] The measurements of the valence shell ionisation energy spectra (6-32 eV) for propane (C₃H₈) by high resolution (ΔE = 0.9 eV and Δp 0.1 a.u.) (e,2e) spectrometer at impact energy of 1200 eV plus binding energy and symmetric non-coplanar kinematics are reported. The spectrum is consistent with a single particle picture of ionization from each of the seven outer-valence orbitals and the three inner-valence orbitals. The ionization energies are in agreement with published photoelectron spectroscopy data

[en] The epithermal neutron is susceptible to the thermal motion of the target nucleus. Traditional Monte Carlo code adopts free gas model to consider the neutron emission energy and angle in epithermal region, the elastic scattering cross sections of epithermal energy range is approximated by a constant (CXS). The neglect of resonance elastic scattering by CXS led to the underestimation of resonance absorption. In order to reduce the calculation error of resonance elastic scattering, it is necessary to use Doppler broadening rejection correction (DBRC) method resonance elastic scattering. In this work, Monte Carlo code RMC was used to model and calculate the core of Qinshan II with DBRC function on and DBRC function off. The k_eff and k_inf at different burnup depths and temperatures are calculated. It is found that the neglect of resonance elastic scattering will bring positive influence of 1 ∼ 169 on k_eff and k_inf, and the influence increases as the temperature increases. (authors)

[en] We investigate the thermal entanglement in the Lipkin-Meshkov-Glick (LMG) model which consists of spin-1/2 particles with XXZ-type exchange interactions between any pair of them. The ferromagnetic (FM) and antiferromagnetic (AFM) cases are completely analyzed at both finite temperature and zero temperature. According to the results obtained by accurate numerical calculation, several interesting physic phenomena and characteristics of thermal entanglement in the LMG model are found. Not only do we evaluate the entanglement of the LMG model, but also discover the correlations between macroscopic physical quantities and thermal entanglement. (general)

[en] The model DYS-92 low background liquid scintillation spectrometer as an new innovation is developed. It is specially designed for measuring extra-low level tritium and ¹⁴C in the environment. Of course, other isotopes, such as ⁸⁵Kr, ³⁶Cl and trace isotopes in the environment can also be measured. DYS-92 is controlled by Z80 main plate in the main instrument box and a microcomputer. Nex electronics has been designed. The software includes: operation, data processing and spectrum analysis. The bismuth germanate (BGO) crystal is applied as an anticoincidence shielding with higher γ efficiency and is lighter and smaller than NaI (Tl) crystal. A lot of messages can be observed from the screen of the computer during measurement, such as counts of each channel, energy spectrum, time, parameters of the measuring process, etc. The statistical data-processing is made in the course of measurement. All of the counts and spectra for any sample can be displayed on the screen by pushing keys. The figure of merit can be calculated from the spectrum by the microcomputer. In particular, the selection of ³H, ¹⁴C measuring channel can be completed after or before the measurement. In either case, the ¹⁴C dating of the sample or the calculation of the concentration of tritium in water can be fulfilled automatically

[en] Nano/micro-indentation has been extensively used to examine elastic properties and creep of cement-based materials. However, there have been inconsistencies in the measured elastic moduli and debate on the creep mechanism of calcium (alumino) silicate hydrates (C-(A-)S-H). To bring new insights, we examined the deviatoric stress-induced preferred orientation of calcium aluminosilicate hydrate (C-A-S-H), portlandite, and ettringite compacts, using synchrotron-based X-ray diffraction. Intense preferred orientations were observed in C-A-S-H compacts, and the c-axis of unit cells is highly aligned with the compression direction; weaker c-axis related fiber-type texture formed in portlandite and ettringite. Higher humidity, greater compacting pressure, and/or increased duration of the pressure intensified the C-A-S-H preferred orientation, which is facilitated by gel-pore water lubrication. This pressure-induced time-dependent preferential re-orientation of crystallites can contribute to the creep of cement-based materials, and it may cause overrepresentation of the soft c-axis of C-(A-)S-H unit-cell in nanoindentation experiments and underestimation of Young's modulus.

[en] The significance and development of (e,2e) scattering by using polarized electrons are shown first, then a polarized (e,2e) spectrometer under developing is introduced, including its main structure and key characters. An optical electron polarimeter is also proposed

[en] Two models of a low-level liquid scintillation counter, the DYS-1 and DYS-2, were designed and manufactured in our laboratory. The DYS-1 is more sensitive than the DYS-2. For the 5 ml sup(14)C benzene samples, an efficiency of 80 percent and a background of 0.54 cpm are obtained from DYS-1; its figure of merit, (Esup(2)/B), exceeds 10,000. The detection limit for tritium in water (50 ml water and 50 ml Instagel scintillator) is approximately 1 Bq/l water (t=30 min, P=68.3 percent). The sensitivity of DYS-2 is better than conventional liquid scintillation counters; for 5 ml sup(14)C benzene samples, the efficiency of the DYS-2 is above 70 percent and its Esup(2)/B varies from 1700 to 2500 depending on the construction of material of the counting vial. When a 10 ml sample of water is mixed with 10 ml of Instagel, a detection limit better than 4 Bq/l water (t=30 min, P=68.3 percent) can be attained. The DYS-1 is a single sample manual liquid scintillation counter which can be used to measure samples in various sizes between 2-100 ml with optimum geometry. The DYS-2 provides an automatic sample-changing system with a capacity of 10 vials and can be used to measure 5-20 ml samples under optimum conditions. Both instruments permit present counting time and print raw data automatically

[en] In order to solve the problem of low parallelism caused by particle load imbalance of Monte Carlo program at the end of iteration, this paper analyzes the advantages and disadvantages of different algorithms, and the nearest neighbor algorithm is used on MOI Monte Carlo program to solve load balancing. Finally, we adapt an example of ten million grid to test this algorithm, it reduces the computation time by at least 10%, and as the burnup deepens, the calculation time will decrease even further. The results show that the algorithm is effective for the problem of particle load imbalance. (authors)

[en] One major challenge to the improvement of regional climate scenarios for the northern high latitudes is to understand land surface feedbacks associated with vegetation shifts and ecosystem biogeochemical cycling. We employed a customized, Arctic version of the individual-based dynamic vegetation model LPJ-GUESS to simulate the dynamics of upland and wetland ecosystems under a regional climate model–downscaled future climate projection for the Arctic and Subarctic. The simulated vegetation distribution (1961–1990) agreed well with a composite map of actual arctic vegetation. In the future (2051–2080), a poleward advance of the forest–tundra boundary, an expansion of tall shrub tundra, and a dominance shift from deciduous to evergreen boreal conifer forest over northern Eurasia were simulated. Ecosystems continued to sink carbon for the next few decades, although the size of these sinks diminished by the late 21st century. Hot spots of increased CH₄ emission were identified in the peatlands near Hudson Bay and western Siberia. In terms of their net impact on regional climate forcing, positive feedbacks associated with the negative effects of tree-line, shrub cover and forest phenology changes on snow-season albedo, as well as the larger sources of CH₄, may potentially dominate over negative feedbacks due to increased carbon sequestration and increased latent heat flux. (letter)