A STUDY ON CELLULAR AUTOMATA BASED ON RELATIONAL DATABASES AND SPATIO-TEMPORAL SIMULATIONS OF CULTURE DIFFUSION

This paper presents a development of the extended Cellular Automata (CA), based on relational databases(RDB), to model dynamic interactions among spatial objects. The integration of Geographical Information System (GIS)and CA has the great advantage of simulating geographical processes. But standard CA has some restrictions in cellularshape and neighbourheod and neighbour rules, which restrict the CA‘s ability to simulate complex, real world environ-ments. This paper discusses a cell‘‘s spatial relation based on the spatial object‘s geometrical and non-geometrical characteris-tics, and extends the cell‘‘ s neighbour definition, and considers that the cell‘ s neighbour lies in the forms of not only spa-tial adjacency but also attribute correlation. This paper then puts forward that spatial relations between two different ceilscan be divided into three types, including spatial adjacency, neighbourheod and complicated separation. Based on tradition-al ideas, it is impossible to settle CA‘‘s restrictions completely. RDB-based CA is an academic experiment, in whichsome fields are designed to describe the essential information needed to define and select a cell‘‘s neighbour. The cultureinnovation diffusion system has multiple forms of space diffusion and inherited characteristics that the RDB-based CA iscapable of simulating more effectively. Finally this paper details a successful case study on the diffusion of fashion weartrends. Compared to the original CA, the RDB-based CA is a more natural and efficient representation of human knowl-edge over space, and is an effective tool in simulating complex systems that have multiple forms of spatial diffusion.     

栖霞地区蓬莱群的时代属震旦纪

通过对栖霞地区蓬莱群进行详细的生物地层工作，除采集到大量微古植物化石外，未发现任何无脊椎动物化石。因此，前人在该区蓬莱群中采到的所谓“腕足类”和“双壳类”化石应予否定。本文重新肯定了栖霞地区蓬莱群的时代属震旦纪．     

Macroalage as a source of alpha-glucosidase inhibitors

Alpha-glucosidase inhibitors were screened from organic solvent extracts of macroalgae by a spectrophotometrical method with p-nitrophenyl-D-glucopyranosidase as the substrate. The result indicates that orgarlic crude extracts from some macroalgae such as Rhodomela confervoides (Huds.) Silva, Gracilaria textorii(Suringar) DeToni, Plocamium telfairiae Harv., Dictyopteris divaricata (Okam.) Okam, Ulval pertusa and Enteromorpha intestinalis (L.) Link et al. show strong inhibitory activity of alpha-glucosidase at concentration of 79.6 μg/ml.     

SPATIAL AND TEMPORAL DYNAMICS OF SOIL ORGANIC CARBON IN RESERVED DESERTIFICATION AREA —A Case Study in Yulin City, Shaanxi Province, China

Soil organic carbon (SOC) was considered to be a key index in evaluation of soil degradation and soil C sequestration. To discuss the spatial-temporal dynamics of SOC in arable layer in reversed desertification area, a case study was conducted in Yulin City, Shaanxi Province, China. Data of SOC were based on general soil survey in 1982 and repeated soil sampling in 2003. Soil organic carbon content (SOCC) was determined by K2Cr3O2-FeSO4 titration method, and soil organic carbon density (SOCD) was calculated by arithmetic average and area weighted average method, respectively. On average, SOCC and SOCD of the arable layer in the study area from 1982 to 2003 had increased 0.5 Ig/kg and 0.16kg/m2, respectively. Considering main soil types, the widest distributed Arid-Sandic Entisols had lowest values and increments of SOCC and SOCD during the study period; while the second widest Los-Orthic Entisols had higher values and increments of SOCC and SOCD, compared to the mean values of the whole region. The results indicated that reversed desertification process was due to the modification of land use and management practices, such as natural vegetation recovery, planting grass, turning arable land to grassland, and soil and water conservation etc., which can improve SOCC and SOCD and thus enhance soil C sequestration.     

海南岛北部晚新生代玄武岩成分演化及成因讨论

板内玄武岩通常具有复杂的成分组成和成因过程。海南岛北部（简称“琼北”）自渐新世始逐渐发育了大量板内玄武岩,岩性跨度大,从石英拉斑玄武岩到橄榄拉斑玄武岩,再到碱性橄榄玄武岩和碧玄岩均有分布。对琼北晚新生代玄武岩虽已开展了广泛的研究,但“琼北晚新生代玄武岩的成分随时间演化规律”这一问题却未引起足够的关注。本文从晚更新世道堂组橄榄玄武岩入手,对其开展了细致的岩石学、矿物学和主微量及Sr- Nd- Pb同位素地球化学的研究;并结合文献中琼北其他时代（组）玄武岩的数据,阐述了琼北晚新生代玄武岩成分随时间演化的规律并对其成因进行了探讨。研究发现,自中—上新世到更新世再到全新世,琼北晚新生代玄武岩呈现从碱性玄武岩过渡到拉斑玄武岩再突变到碱性—强碱性系列的演化规律;中—上新世到更新世这一时期的碱性玄武岩和拉斑玄武岩可能形成于石榴子石二辉橄榄岩由低到高程度的部分熔融作用,而全新世碱性岩则更可能形成于石榴子石辉石岩的部分熔融。琼北晚新生代玄武岩的Sr- Nd- Pb同位素组成揭示其源区地幔以PREMA端元为主,但经历了来自古老陆壳的沉积物不同程度的改造作用。采用“海南地幔柱”模型可以较好地解释琼北晚新生代玄武岩的复杂组成和成因。     

Correlation between the tilt anomaly on the vertical pendulum at the Songpan station and the 2021 MS7.4 Maduo earthquake in Qinghai province,China

Understanding the relationship between precursory deformation anomalies and strong earthquakes is vital for physical earthquake prediction. Six months before the 2021 M_S7.4 Maduo earthquake in Qinghai province, China, the vertical pendulum at the Songpan station was observed to tilt southward with a high rate and large amplitude. Studies conducted before the 2021 M_S7.4 Maduo earthquake inferred the tilt anomaly to be an earthquake precursor. However, after the earthquake, the relation between the earthquake and the anomaly became controversial, partly because the Songpan station is located at a great distance from the epicenter. In this study, based on the deformation anomaly characteristics, relationship between the seismogenic fault and the fault near the anomaly, and associated quantitative analyses, we concluded that this anomaly may be associated with the 2021 M_S7.4 Maduo earthquake. The duration and amplitude of this anomaly matched with the magnitude and epicenter distance of the Maduo earthquake. We have also interpreted the reason why the anomaly occurred near a fault that is obliquely intersected with the seismogenic fault and why the anomaly is located far from the earthquake epicenter.     

An anionic biopolymer γ-polyglutamate enhanced the microbially induced carbonate precipitation for soil improvement: mechanical behaviors and underlying mechanism

The use of biopolymer to improve the performance of microbially induced carbonate precipitation (MICP)-treated sands is a novel and eco-friendly concept. This work found an anionic biopolymer, γ-polyglutamate (γ-PGA), could significantly improve the performance of MICP-treated sands. Comparing the control with absence of γ-PGA, the concentration of 0.1–9 g/L γ-PGA increased the compressive strength of MICP-treated sands by 1.54–3.96 times and significantly reduced the brittleness. The MICP process analysis and microstructural detection demonstrated that γ-PGA in the specimens provided many nucleation sites and templates for calcite generation, partially kept the bacterial urease activity by replacement of the bacteria as nucleation sites, thereby improving the calcite generation. The γ-PGA also cemented sand grains with calcite through the hydrogen bond-type intermolecular interactions. Both the calcite generation and the hydrogen bond-type intermolecular interactions by γ-PGA played vital roles in enhancing MICP for soil improvement. Additionally, γ-PGA, as a viscoelastic admixture between the crystals and sand grains, effectively dissipated the energy of stress and thus reduced the brittleness of MICP-treated sands. This is the first report on the application of anionic biopolymer to MICP technology. It provides a novel concept in promoting the efficiency and sustainability of MICP.

     

Dynamic Response of Shallow-Buried Small Spacing Tunnel with Asymmetrical Pressure: Shaking Table Testing and Numerical Simulation

A series of shaking table tests were designed and carried out to study the seismic behaviors of a shallow-buried small spacing tunnel with asymmetrical pressure. The key details to shaking table model test, including test equipment, model similarity relation, similarity constant, model box, physical model, layout of transducers, seismic waves, and loading system were presented. The numerical simulation of the shaking table test was also carried out by using a finite element simulation software. The results show that: (1) the Fourier spectrums in the vertical direction and horizontal direction are different at the same measuring point. The structure of tunnel transforms the Fourier spectrum of horizontal direction. (2) The stability of middle rock pillar is poor under seismic wave action. The anchor plays an important role in strengthening the stability of middle rock pillar. The dynamic strain of anchor has accumulative effect. (3) The numerical simulation results are in significant agreement with the shaking table test results. (4) Compared with type of seismic wave, peak seismic wave has a significant effect on acceleration response of tunnel. The peak acceleration response of the tunnel is linear with the peak seismic wave, in the horizontal direction. The peak acceleration response is nonlinear in the vertical direction. (5) The axial force of cross section at arch foot is larger than other position. The shock absorption effect of 10 cm seismic isolation layer is better than 5 and 20 cm.     

Experiment and Study on Mechanical Property of Sandstone Post-peak Under the Cyclic Loading and Unloading

Engineering research has shown that the surrounding rock of deep roadways experienced many times of post-peak cyclic loading and unloading. So studying on rock mechanical characteristics of post-peak loading and unloading is helpful to control the deep surrounding rocks. The test using RMT-150B rock mechanics testing system, to experiment on the mechanical properties of sandstone of post-peak cyclic loading and unloading. The results show that: the stress–strain curves of post-peak cyclic loading and unloading have significant plastic hysteretic loops. The area of plastic hysteretic loops gloss back. The enveloping outer enclosure of cycle loading curve is the similar as the stress–strain curves of strain softening stage when the samples failure, which shows that post-peak failure of rocks have significant memory. With the increase of cycles, the cumulative deterioration parameters are gradually increased, and the ultimate bearing capacity, elastic of loading section of samples and cumulative deterioration parameters conform with the exponential attenuation function with constant term. With the increase of surrounding pressure, the total energy, dissipated energy and elastic energy of samples are gradually increased. With the increase of cycles, the total energy, dissipated energy and elastic energy of samples all are gradually decreasing, the rate of reduction decreases gradually. The samples exist in vertical splitting and transverse shear combination failure under the post-peak uniaxial cycles, or exist in shear failure under the post-peak triaxial cycles. The shear plane exists slip traces.