Tibet is located at the southwest boundary of China. It is the main body of the Qinghai-Tibet Plateau, the highest and the youngest plateau in the world. Owing to complicated geology, Neo-tectonic movements, geomorpho...Tibet is located at the southwest boundary of China. It is the main body of the Qinghai-Tibet Plateau, the highest and the youngest plateau in the world. Owing to complicated geology, Neo-tectonic movements, geomorphology, climate and plateau environment, various mountain hazards, such as debris flow, flash flood, landslide, collapse, snow avalanche and snow drifts, are widely distributed along the Jinsha River (the upper reaches of the Yangtze River), the Nu River and the Lancang River in the east, and the Yarlungzangbo River, the Pumqu River and the Poiqu River in the south and southeast of Tibet. The distribution area of mountain hazards in Tibet is about 589,000 km2, 49.3% of its total territory. In comparison to other mountain regions in China, mountain hazards in Tibet break out unexpectedly with tremendously large scale and endanger the traffic lines, cities and towns, farmland, grassland, mountain environment, and make more dangers to the neighboring countries, such as Nepal, India, Myanmar and Bhutan. To mitigate mountain hazards, some suggestions are proposed in this paper, such as strengthening scientific research, enhancing joint studies, hazards mitigation planning, hazards warning and forecasting, controlling the most disastrous hazards and forbidding unreasonable human exploring activities in mountain areas.展开更多
The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The resu...The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The results showed that the P adsorption capacity of the organo-mineral colloidal complexes differed with the soil types, being higher for the acid and calcareous purple soils than for the neutral purple soils. Partial removal of the organic matter increased the adsorption capacity of the colloidal complexes. A very significant positive correlation was found between the amounts of P desorbed from OMC and the P saturation degrees.The P adsorption reaction was quick at the early stage and slowed later. The raise of temperature increased P adsorption capacity and P adsorption rate of the colloidal complexes. The adsorption processes could be described by the Elovich equation.展开更多
Since the solvent evaporation of a droplet on a hydrophobically pretreated glass slide, femtomole amount of fluorescent materials is carried by the evaporation and results in outward capillary flow to the perimeter of...Since the solvent evaporation of a droplet on a hydrophobically pretreated glass slide, femtomole amount of fluorescent materials is carried by the evaporation and results in outward capillary flow to the perimeter of the droplet spot where the solute deposits, and forms a fluorescent ring like deposit (RLD) with submicrometer-scale structures.展开更多
Modeled with a three-level-atom appropriate to 980 nm pumped amplifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been...Modeled with a three-level-atom appropriate to 980 nm pumped amplifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been specified.展开更多
We introduce the notion of the contraction integrated semigroups and give the Lumber-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their appl...We introduce the notion of the contraction integrated semigroups and give the Lumber-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their application, a necessary and sufficient condition for q-matrices Q generating a contraction integrated semigroup is given, and a necessary and sufficient condition for a transition function to be a Feller-Reuter-Riley transition function is also given in terms of its q-matrix.展开更多
In this paper, we generalize Clifford semirings to left Clifford semirings bymeans of the so-called band semirings. We also discuss a special case of this kind of semirings,that is, strong distributive lattices of lef...In this paper, we generalize Clifford semirings to left Clifford semirings bymeans of the so-called band semirings. We also discuss a special case of this kind of semirings,that is, strong distributive lattices of left rings.展开更多
The ab initio molecular orbital method is employed to study the enantioselective reduction of acetophenone with borane catalyzed by thiazolidinooxazaborolidine. Computation result shows that the controlling step for t...The ab initio molecular orbital method is employed to study the enantioselective reduction of acetophenone with borane catalyzed by thiazolidinooxazaborolidine. Computation result shows that the controlling step for the reduction is the decomposition of the catalyst-alkoxyborane adduct and the reduction leads to S-alcohols. The transition state of the hydride transfer from the borane moiety to the carbonyl carbon of acetophenone is a twisted chair structure with a B(2)-N(3)-B BH 3-H BH 3-C CO-O CO 6-membered ring.展开更多
Previous researches on non-English majors' English writing mainly focus on the case studies of process-oriented writing,collaborative writing, writing through groups, coherent ties and chains, or writing strategie...Previous researches on non-English majors' English writing mainly focus on the case studies of process-oriented writing,collaborative writing, writing through groups, coherent ties and chains, or writing strategies used in non-English majors' English writing. Little research has been done on the relationship between learners' cognitive ability and their展开更多
基金This research is supported by the West Key Research Project of the National Natural Science Foundation of China(No.90202007)the Researcher Introduced Project of Chengdu Institute of Mountain Hazards and Environment,the Chinese Academy of Sciences&Ministry of Water Conservancy(Y1006).
文摘Tibet is located at the southwest boundary of China. It is the main body of the Qinghai-Tibet Plateau, the highest and the youngest plateau in the world. Owing to complicated geology, Neo-tectonic movements, geomorphology, climate and plateau environment, various mountain hazards, such as debris flow, flash flood, landslide, collapse, snow avalanche and snow drifts, are widely distributed along the Jinsha River (the upper reaches of the Yangtze River), the Nu River and the Lancang River in the east, and the Yarlungzangbo River, the Pumqu River and the Poiqu River in the south and southeast of Tibet. The distribution area of mountain hazards in Tibet is about 589,000 km2, 49.3% of its total territory. In comparison to other mountain regions in China, mountain hazards in Tibet break out unexpectedly with tremendously large scale and endanger the traffic lines, cities and towns, farmland, grassland, mountain environment, and make more dangers to the neighboring countries, such as Nepal, India, Myanmar and Bhutan. To mitigate mountain hazards, some suggestions are proposed in this paper, such as strengthening scientific research, enhancing joint studies, hazards mitigation planning, hazards warning and forecasting, controlling the most disastrous hazards and forbidding unreasonable human exploring activities in mountain areas.
基金the Applied Science Foundation of the Science and Technology Commission of Chongqing,China.
文摘The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The results showed that the P adsorption capacity of the organo-mineral colloidal complexes differed with the soil types, being higher for the acid and calcareous purple soils than for the neutral purple soils. Partial removal of the organic matter increased the adsorption capacity of the colloidal complexes. A very significant positive correlation was found between the amounts of P desorbed from OMC and the P saturation degrees.The P adsorption reaction was quick at the early stage and slowed later. The raise of temperature increased P adsorption capacity and P adsorption rate of the colloidal complexes. The adsorption processes could be described by the Elovich equation.
文摘Since the solvent evaporation of a droplet on a hydrophobically pretreated glass slide, femtomole amount of fluorescent materials is carried by the evaporation and results in outward capillary flow to the perimeter of the droplet spot where the solute deposits, and forms a fluorescent ring like deposit (RLD) with submicrometer-scale structures.
文摘Modeled with a three-level-atom appropriate to 980 nm pumped amplifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been specified.
文摘We introduce the notion of the contraction integrated semigroups and give the Lumber-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their application, a necessary and sufficient condition for q-matrices Q generating a contraction integrated semigroup is given, and a necessary and sufficient condition for a transition function to be a Feller-Reuter-Riley transition function is also given in terms of its q-matrix.
文摘In this paper, we generalize Clifford semirings to left Clifford semirings bymeans of the so-called band semirings. We also discuss a special case of this kind of semirings,that is, strong distributive lattices of left rings.
基金ProjectsupportedbytheScienceFoundationofNationalEducationMinistry (No .9910 6 )
文摘The ab initio molecular orbital method is employed to study the enantioselective reduction of acetophenone with borane catalyzed by thiazolidinooxazaborolidine. Computation result shows that the controlling step for the reduction is the decomposition of the catalyst-alkoxyborane adduct and the reduction leads to S-alcohols. The transition state of the hydride transfer from the borane moiety to the carbonyl carbon of acetophenone is a twisted chair structure with a B(2)-N(3)-B BH 3-H BH 3-C CO-O CO 6-membered ring.
文摘Previous researches on non-English majors' English writing mainly focus on the case studies of process-oriented writing,collaborative writing, writing through groups, coherent ties and chains, or writing strategies used in non-English majors' English writing. Little research has been done on the relationship between learners' cognitive ability and their
