Synthesis and characterization of novel Group VI metal (Mo, W) nitride and oxide compounds

Binary Group VI metal nitrides are characterized by thermodynamic instability towards dissociation to N2 and the N-saturated elements at high temperature. Our investigations into the preparation of tungsten nitrides have involved the synthesis of molecular precursors, and their conversion to tungsten nitrides at relatively low temperatures. Two interesting molecular precursors, (WNCl3·NCCH3] 4 and WN(N3)3· xNCCH3, have been prepared and characterized. The molecular structure of (WNCl3·NCCH3] 4 consists of a W4N4 tetrameric core with multiple and single W-N bonds arranged in an alternating fashion. Three new solid state phases, amorphous W3N5, cubic WN, and W2N2(C2N2), have been discovered by solid state and chemical vapor transport reactions. Cubic WN has a rock salt structure. W2N2(C2N2) has a novel three-dimensional network structure consisting of W2 dimers, hydrazido ligands N24-, and 1,4-diazabutenido ligands represented by three resonance structures, (N-C=C-N) 6-, (N=C-C-N) 6- and (N-C-C=N) 6-;Ternary reduced molybdenum oxides have caused great interest, since the discovery of NaMo4O6 containing trans-edge-shared Mo6 octahedra. Recent investigations have yielded a new family of LnMO8O14 compounds containing cis- and trans-Mo8 bicapped octahedra. A systematic study in the Ln2O3-MoO3-MO (Ln = La, Ce, Pr, Nd, Sm) system has been explored to better understand LnMO8O14. The study has shown that the sizes of the rare-earth cations affect the formation of these phases. Larger cations (La, Ce, and Pr) aid in the formation of trans-Mo8 bicapped octahedra, and the smaller cations (Nd, Sm) only stabilize the cis-Mo8 bicapped octahedra. Magnetic susceptibility measurements have indicated that no effective moment contribution arises from the Mo8 metal clusters, even though the cis-Mo8 cluster in LnMo8O14, containing all cis-Mo8 octahedra, apparently contains an odd number of electrons (23). Electrical resistivity measurements and electronic structure calculations have shown that the LnMo8O14 compounds containing cis-Mo8 clusters are metallic, and the LnMo8O14 compounds containing a 1:1 ratio of cis- to trans-Mo8 clusters are semiconducting

Searching for the parallel growth of cities

Three urban growth theories predict parallel growth of cities. The endogenous growth theory predicts deterministic parallel growth; the random growth theory implies that city growth follows Gibrat’s law with a steady-state distribution; and the hybrid growth theory suggests the co-movement of random city growth. This paper uses the Chinese city size data from 1984-2006 and time series econometric techniques to test for parallel growth. The results from various types of stationarity tests on pooled heterogeneous cities show that city growth is random. However, once growth trend and structural change are taken into account, certain groups of cities with common group characteristics, such as similar natural resource endowment or policy regime, grow parallel.Urban growth; Parallel growth; Zipf’s law; Unit root; Structural change

China trade with the United States in some important commodities from 1946 to 1948 (Tung oil and bristle as exports-cotton, petroleum and tobacco as imports)

Thesis (M.A.)--Boston University, 1950. Written by Zhihong Zhang (Chih-hung Chang).As the Communist's control nearly the whole of China, it will be interesting to watch the trade between China and the United States in the future. America depends upon China for certain raw materials and China depends upon America ror many commodities, especially capital goods as they are needed badly in the stage of industrialization. To anticipate the future we must review the past; the trade during the Second World War was so abnormal that its data is of little value. The trade during the postwar years is more representative, but strongly influenced by war-created demand. Therefore, a relatively accurate picture might be obtained by examining the postwar trade situation in comparison with prewar data. The real causes behind the factual data are certainly the important things that we are looking for as guides to future trends of the trade between the two countries. It is certainly not feasible for me to investigate all the commodities which flow between these two countries in such a short period of time. As a result, I select some of the more important commodities and some of which hold great personal interest ror me. Upon the termination or the War, China found herself in a desperate economic condition. Peace was not her lot. Civil War brought new surrering and new dislocations to her people and their political economy. Inflation, followed by an unrealistic approach to economic problems on the part of an ill-prepared, inefficient government, provided no firm basis for internal or external trade. However, the trade between the two countries, China and the United States, was resumed. Since the war, America was the only nation able to export surplus goods as well as to provide foreign loans and aid funds. This gave the United States the dominant position in China's markets in the postwar years. On the other hand, China's share in the United States' imports was insignificant. China shared the United States' exports for the years 1946-1948 only 3.0% on the average while the imports she shared from the United States was only 1.8% on the average for the same period. China's most important import, raw cotton, amounted to $76 .5 million on the average for postwar years. In the prewar years, the possession by China of suitable natural conditions for cotton cultivation in many parts and availability of cheap labor had enabled her to become one of the world's largest cotton producers. The postwar cotton textile industry declined along with a sharp reduction in domestic production or cotton. But in the future, China should supply her own needs with cotton grown in her own fields. The prospect for tobacco leaf trade between these two countries is also not bright as China gradually succeeded in cultivating America seed tobacco suitable for her rising cigarette industry. Furthermore, her domestic production in the postwar years had already approximately reached her domestic requirement. The shortage is due primarily to disrupt transportation. China has petroleum resources which could supply her own needs at least in the first stage of industrialization. But her resources are located in the far West which could not be economically reached her existing transportation facilities. Their development will also require large production equipment probably originating in the United States. Therefore, China will continually be a good market for American petroleum products for some time to come. As to two exports, tung oil and bristles, America will continue to import them from China. Although the American tung oil industry made considerable progress in the cultivation of the tree and production of the oil, it is not very successful because of unsuitable soil and climate conditions. Furthermore, its supply is still far from meeting domestic demands. Due to the product's unique qualities, none of the substitutes could successfully replace this oil. America cannot also completely replace the bristle by synthetic fiber primarily because of special characteristics. However, in the case of shortage of the supply of the natural bristles, there would undoubtedly result an accelerated demand for the synthetic products and increased research to develop synthetic products with the characteristics of the natural. Our conclusion, therefore, is that China will enjoy a virtual monopoly in America's tung oil trade. On account of the rise of synthetic fibers, the prospect of bristles is more doubtful but will depend on whether China can maintain high quality, regular arrival and a reasonable price. The United States' exports to China of their three commodities - cotton, tobacco and petroleum - have not so bright a future. However, she may gain in export by selling China capital goods. Because, once an industrial China takes shape, she will need more and more industrial machinery, locomotives, vehicles, electrical equipment, aircraft and so on. But it is becoming clearer and clearer that trade between these two countries will depend on political developments now in the making

Conditional knowledge-based coherence strategy choice : engaging supervisory on-script corrective feedback in research writing

Research writing has been traditionally considered a challenging task for international Chinese Higher-Degree-by-Research (HDR) students, particularly at their novice stage as a writer. To help them conquer the challenges, supervisory on-script focused corrective feedback is a pedagogical method for providing models of conditional knowledge and helping produce coherent research writing. This supervisory pedagogy has been researched (Aitchison et al., 2012; Can & Walker, 2014). However, the pedagogical use of schemas and conditional knowledge as a facilitator for successful research writing are under researched with respect to international Chinese HDR students. This lack of knowledge limits the pedagogical possibilities for building international Chinese HDR students’ capacity for creating coherent research writing. Investigating the possibilities for improving their conditional knowledge and schemas can help address this challenge. This warrants a new approach to developing pedagogies that improve HDR students’ research writing, one that captures a dynamic view of the development of their conditional knowledge and schemas in a coherent hierarchy. In this doctoral study, the investigation focuses on the construction of conditional knowledge for creating micro-level coherence in research writing engaged by supervisory on-script corrective feedback. To this end, the potential for engaging conditional knowledge and schemas involves analysing evidence of international Chinese HDR students’ coherence strategy choices and their supervisor’s corresponding on-script corrective feedback. This study points to the need for pedagogies that accommodate text-based and reader-based coherence in HDR students’ research writing. The primary aims of the research reported in this thesis were to investigate the interrelationships among (a) international Chinese HDR students’ conditional knowledge used in creating the micro-level coherence; (b) their choices of the coherence strategies used; and (c) their supervisor’s modelling of appropriate choices of coherence strategies via on-script focused corrective feedback on these students’ draft research texts. The case study used interrelated approaches to address these aims. First, this study explored the appropriateness or otherwise of these HDR students’ use of coherence strategies through collecting and analysing evidence of the conditional knowledge they used in creating the micro-level coherence in their research writing. Second, a key pedagogy used to enhance their conditional knowledge for creating coherence, supervisory on-script focused corrective feedback, was developed. Through mapping, categorising and conceptualising the conditional knowledge required for creating the micro-level coherence in HDR students’ research writing, this study connects text-based and reader-based coherence. This study thereby develops a new supervision pedagogy which recognises and mobilises supervisor’s modelling of conditional knowledge for enhancing HDR students’ conditional knowledge in order to build HDR students’ capabilities for producing coherent research writing

China trade with the United States in some important commodities from 1946 to 1948 (Tung oil and bristle as exports-cotton, petroleum and tobacco as imports)

Thesis (M.A.)--Boston University, 1950. Written by Zhihong Zhang (Chih-hung Chang).As the Communist's control nearly the whole of China, it will be interesting to watch the trade between China and the United States in the future. America depends upon China for certain raw materials and China depends upon America ror many commodities, especially capital goods as they are needed badly in the stage of industrialization. To anticipate the future we must review the past; the trade during the Second World War was so abnormal that its data is of little value. The trade during the postwar years is more representative, but strongly influenced by war-created demand. Therefore, a relatively accurate picture might be obtained by examining the postwar trade situation in comparison with prewar data. The real causes behind the factual data are certainly the important things that we are looking for as guides to future trends of the trade between the two countries. It is certainly not feasible for me to investigate all the commodities which flow between these two countries in such a short period of time. As a result, I select some of the more important commodities and some of which hold great personal interest ror me. Upon the termination or the War, China found herself in a desperate economic condition. Peace was not her lot. Civil War brought new surrering and new dislocations to her people and their political economy. Inflation, followed by an unrealistic approach to economic problems on the part of an ill-prepared, inefficient government, provided no firm basis for internal or external trade. However, the trade between the two countries, China and the United States, was resumed. Since the war, America was the only nation able to export surplus goods as well as to provide foreign loans and aid funds. This gave the United States the dominant position in China's markets in the postwar years. On the other hand, China's share in the United States' imports was insignificant. China shared the United States' exports for the years 1946-1948 only 3.0% on the average while the imports she shared from the United States was only 1.8% on the average for the same period. China's most important import, raw cotton, amounted to $76 .5 million on the average for postwar years. In the prewar years, the possession by China of suitable natural conditions for cotton cultivation in many parts and availability of cheap labor had enabled her to become one of the world's largest cotton producers. The postwar cotton textile industry declined along with a sharp reduction in domestic production or cotton. But in the future, China should supply her own needs with cotton grown in her own fields. The prospect for tobacco leaf trade between these two countries is also not bright as China gradually succeeded in cultivating America seed tobacco suitable for her rising cigarette industry. Furthermore, her domestic production in the postwar years had already approximately reached her domestic requirement. The shortage is due primarily to disrupt transportation. China has petroleum resources which could supply her own needs at least in the first stage of industrialization. But her resources are located in the far West which could not be economically reached her existing transportation facilities. Their development will also require large production equipment probably originating in the United States. Therefore, China will continually be a good market for American petroleum products for some time to come. As to two exports, tung oil and bristles, America will continue to import them from China. Although the American tung oil industry made considerable progress in the cultivation of the tree and production of the oil, it is not very successful because of unsuitable soil and climate conditions. Furthermore, its supply is still far from meeting domestic demands. Due to the product's unique qualities, none of the substitutes could successfully replace this oil. America cannot also completely replace the bristle by synthetic fiber primarily because of special characteristics. However, in the case of shortage of the supply of the natural bristles, there would undoubtedly result an accelerated demand for the synthetic products and increased research to develop synthetic products with the characteristics of the natural. Our conclusion, therefore, is that China will enjoy a virtual monopoly in America's tung oil trade. On account of the rise of synthetic fibers, the prospect of bristles is more doubtful but will depend on whether China can maintain high quality, regular arrival and a reasonable price. The United States' exports to China of their three commodities - cotton, tobacco and petroleum - have not so bright a future. However, she may gain in export by selling China capital goods. Because, once an industrial China takes shape, she will need more and more industrial machinery, locomotives, vehicles, electrical equipment, aircraft and so on. But it is becoming clearer and clearer that trade between these two countries will depend on political developments now in the making