An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and proce...An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and processing methods are illus-trated. The point cloud results are analyzed in detail. The rescale range analysis method was used to analyze the deformation char-acteristics of the slope. The results show that the trend of slope displacement is stable and that the degree of landslide danger is low. This work indicates that 3-D laser image scanning can supply multi-parameter, high precision real time data over long distances. These data can be used to study the distortion of the slope quickly and accurately.展开更多
Three-River Headwaters (TRH) region involved in this paper refers to the source region of the Changjiang (Yangtze) River, the Huanghe (Yellow) River and the Lancang River in China. Taking the TRH region of the Q...Three-River Headwaters (TRH) region involved in this paper refers to the source region of the Changjiang (Yangtze) River, the Huanghe (Yellow) River and the Lancang River in China. Taking the TRH region of the Qing- hai-Tibet Plateau as a case, the annual evapotranspiration (ET) model developed by Zhang et al. (2001) was applied to evaluate mean annual ET in the alpine area, and the response of annual ET to land use change was analyzed. The plant-available water coefficient (w) of Zhang's model was revised by using vegetation-temperature condition index (VTCI) before annual ET was calculated in alpine area. The future land use scenario, an input of ET model, was spa- tially simulated by using the conversion of land use and its effects at small regional extent (CLUE-S) to study the re- sponse of ET to land use change. Results show that the relative errors between the simulated ET and that calculated by using water balance equation were 3.81% and the index of agreement was 0.69. This indicates that Zhang's ET model based on revised plant-available water coefficient is a scientific and practical tool to estimate the annual ET in the al- pine area. The annual ET in 2000 in the study area was 221.2 ram, 11.6 mm more than that in 1980. Average annual ET decreased from southeast to northwest, but the change of annual ET between 1980 and 2000 increased from southeast to northwest. As a vast and sparsely populated area, the population in the TRH region was extremely unbalanced and land use change was concentrated in very small regions. Thus, land use change had little effect on total annual ET in the study area but a great impact on its spatial distribution, and the effect of land use change on ET decreased with in- creasing precipitation. ET was most sensitive to the interconversion between forest and unused land, and was least sen- sitive to the interconversion between cropland and low-covered grassland.展开更多
Cooling energy needs, for mines in Northern Ontario, are mainly driven by the mining depth and its operation. Part I of this research focusses on the thermal energy loads in deep mines as a result of the virgin rock t...Cooling energy needs, for mines in Northern Ontario, are mainly driven by the mining depth and its operation. Part I of this research focusses on the thermal energy loads in deep mines as a result of the virgin rock temperature, mining operations and climatic conditions. A breakdown of the various heat sources is outlined, for an underground mine producing 3500 tonnes per day of broken rock, taking into consideration the latent and sensible portions of that heat to properly assess the wet bulb global temperature. The resulting thermal loads indicate that cooling efforts would be needed both at surface and underground to maintain the temperature underground within the legal threshold. In winter the air might also have to be heated at surface and cooled underground, to ensure that icing does not occur in the inlet ventilation shaft-the main reason why coolin~ cannot be focussed solely at surface.展开更多
AIM: To determine the and clinical features of prevalence, histologic types primary epithelial tumours of the vermiform appendix in a predominantly black population.METHODS: All cases of primary tumours of the appen...AIM: To determine the and clinical features of prevalence, histologic types primary epithelial tumours of the vermiform appendix in a predominantly black population.METHODS: All cases of primary tumours of the appendix identified by review of the histopathology records at the University of the West Indies between January 1987 and June 2007 were selected. Relevant pathologic and clinical data were extracted with supplementation from patient charts where available. Non-epithelial tumours were excluded. The total number of appendectomy specimens over the period was also ascertained.RESULTS: Forty-two primary epithelial tumours were identified out of 6 824 appendectomies yielding a prevalence rate of approximately 0.62%. Welldifferentiated neuroendocrine cell tumours (carcinoids, 47.6%) and benign non-endocrine cell tumours (adenomas, 45.2%) were most common with nearly equal frequency. The median age was 43 years, with no sex predilection. Carcinoid tumours occurred in younger patients (mean age 32 years), with a male-to-female ratio of 1.2:1. A clinical diagnosis of acute appendicitis was the most common reason for appendectomy (57.1%) and was histologically confirmed in 75% (18 of 24) of cases. In total, 16.7% of cases were diagnosed after incidental appendectomy.CONCLUSION: Appendiceal epithelial tumours are rare in our experience, and are represented principally by carcinoid turnours and adenornas. Carcinoid tumours occurred in younger patients but were slightly more common in men than women. Tumours were not suspected clinically and were diagnosed incidentally in specimens submitted for acute appendicitis supporting the need for histological evaluation in all resection specimens.展开更多
De-farming slope farmland has been an effective measure in recent years to improve environment and prevent soil and water loss on the Loess Plateau.There are different views about the defarming method,and also various...De-farming slope farmland has been an effective measure in recent years to improve environment and prevent soil and water loss on the Loess Plateau.There are different views about the defarming method,and also various de-farming patterns have been put into practice.This paper takes the Yangou Watershed in Shaanxi Province of China as a case for studying the comprehensive benefits of transforming slope farmland to terraces.Based on the day-by-day meteorological data of the Yan'an station in 2005 and the data of terrain features,soil and land use data of the Yangou Watershed,the impact of transforming slope farmland on terraces were simulated and analyzed in aspects of yield increase and water-soil conservation under different topographic conditions with the aid of software WIN-YIELD.Furthermore,an empirical analysis was applied to study the effects of transforming slope farmland to terraces in the Yangou Watershed.The results show that:(1) The bigger the topographic gradient is,the more remarkable benefits it has in yield increase and water-soil conservation.(2) Farmland with slope below 5° could be retained,but farmland with slope above 15° should be converted to forest or grassland as soon as possible.(3) Transforming slope farmland to terraces has the same remarkable effects as the current policy of "Relieving and de-farming" in improving agricultural production conditions,safeguarding food security,raising permanent vegetation coverage rate,and preventing soil and water loss.Besides,it is more cost-effective than the policy of "Relieving and de-farming".It's strongly suggested that the policy of transforming slope farmland to terraces be carried out on the Loess Plateau without delay.展开更多
Based on the petroleum processing units of a certain domestic refinery, the authors studied the appropriate cases for processing of Tahe medium gravity crude. The influence of three crude processing cases, including t...Based on the petroleum processing units of a certain domestic refinery, the authors studied the appropriate cases for processing of Tahe medium gravity crude. The influence of three crude processing cases, including the case for processing of crude slate blended with Tahe medium gravity crude, the case for separate processing and storing of individual crude oils, and the case for flash distillation of Tahe medium gravity crude coupled with separated processing of crude oils, on the products quality, stability of production operation and the overall techno-economic parameters was investigated. The study results have shown that the case for processing crude slate blended with Tahe medium gravity crude could lead to deterioration of the FCC products distribution, dramatic reduction of light distillates, significant surge of sulfur content in FCC naphtha, and increased specific consumption of FCC catalyst, indicating that this case was obviously not suited for processing the Tahe medium gravity crude. The case for separate processing and storing of individual crude oils, however, could increase the aggregate salable products ratio, but the frequent switchover of process streams could cause difficulty and hazards to the stabilization of refining operations, which could not be an ideal processing case. The case for flash distillation of Tahe medium gravity crude coupled with separate processing of crude oils featured the simplicity of process scheme, easiness for modification of process units, easy operation and a slight increase in the aggregate salable products ratio, making itself a suitable case for processing the Tahe medium gravity crude.展开更多
In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberration free optical devices. The tip-tilt of facet in a mirror array is produced...In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberration free optical devices. The tip-tilt of facet in a mirror array is produced by digitally controlled line-tilts of rows and columns. It has not only provided a cost-effective designing methodology in optical physics but also led to a much finer precision of 1 mili arc sec or less. As examples of the application of the proposed digitalised optics, two case studies have been given: a 10 m Schmidt telescope (off-axis) and an 8 m Cassegrain telescope (on-axis).展开更多
Objective:The aim of the study was to explore the therapeutic efficacy and safety of batroxobin in patients with primary hepatic carcinoma(PHC) and the advantages of transcatheter arterial perfusion of batroxobin comb...Objective:The aim of the study was to explore the therapeutic efficacy and safety of batroxobin in patients with primary hepatic carcinoma(PHC) and the advantages of transcatheter arterial perfusion of batroxobin combined with transcatheter arterial chemoembolization(TACE).Methods:Forty patients with PHC were randomized into experimental group(transcatheter arterial perfusion of batroxobin combined with TACE treatment,20 patients) and control group(TACE alone group,20 patients).The patients were followed up and the data were recorded,compared and analyzed.Results:(1) Compared with the control group,the FIB level in the experimental group was significantly decreased at the first month after treatment(P < 0.05).(2) The baseline of the tumor was shortened in both groups after the treatment.There was a significant difference between the two groups at different time intervals(P < 0.05).(3) After the treatment,there was a significant difference of progression-free survival(PFS) levels between the two groups(t =2.877,P < 0.05).(4) The incidence of metastasis were 5.0%(1/20) in both groups at 6 months after treatment,and that after one year was 10.0%(2/20) in the experimental group and 25.0%(5/20) in the control group.However,the difference was not significant(χ2 = 0.693,P > 0.05).Conclusion:Batroxobin can rapidly and effectively decrease the FIB level of the PHC cases.Therefore it may be used as an effective and safe adjuvant drug for the treatment of primary hepatic carcinomas.Transcatheter arterial perfusion of batroxobin combined with TACE therapy has advantages in comparison with TACE alone therapy.It could be taken as a new therapeutic regimen in the PHC treatment.展开更多
With finite computation precision, digital chaos will lose chaotic characteristic. An efficient perturbance-based algorithm perturbing chaos variable algorithm(PCV) was proposed, which can be regarded as a remedy to d...With finite computation precision, digital chaos will lose chaotic characteristic. An efficient perturbance-based algorithm perturbing chaos variable algorithm(PCV) was proposed, which can be regarded as a remedy to digital chaos. After being perturbed, digital chaos systems are able to generate pseudo random sequences with perfect statistical properties and can be used as key stream generators in cryptogram.展开更多
Reinforcement bar corrosion depends heavily on environment and the processes used. This study will address galvanic corrosion. Based on a case study of galvanic corrosion in a guyed power transmission tower, experimen...Reinforcement bar corrosion depends heavily on environment and the processes used. This study will address galvanic corrosion. Based on a case study of galvanic corrosion in a guyed power transmission tower, experiments using a number of methods were made on a small sample of eight poles chosen for excavation and visual inspection, to assess the various resulting diagnoses. Method that provided the best results both in location and classification of the points was adopted, where corrosion had already begun, considering the concern of finding a non-evasive process. To diagnose the status of the poles inserted in rock, after applying the methods, the main types of corrosion affecting them were listed and classified. With the results, the possible means of preventing and maintaining the structure were presented.展开更多
Considering the low average rainfall in the country and the importance of groundwater as a water supply source for drinking and agricultural water sections, water quality condition of groundwater must be controlled an...Considering the low average rainfall in the country and the importance of groundwater as a water supply source for drinking and agricultural water sections, water quality condition of groundwater must be controlled and prevented from any contamination. Identifying the vulnerable areas to pollution is one way of prevention. Many models have been offered for this purpose. In this study, a numerical rating scheme, called DRASTIC has been used for evaluating potential for groundwater pollution in pelly-mianrudan plain that is located in northern Lalli city in Khuzestan province. Resulted map obtained in GIS environment shows that the study area has DRASTIC index of 71-150 that is divided to five vulnerable zones namely no significance, very low, low, low to moderate, moderate to high. Maximum groundwater vulnerability correspondent low to medium zone that approximately covers 45 percentage of the study area and other parts on the northwest and center of the study area has high vulnerability. The sensitivity analysis showed that correlation DRASTIC index with net Recharge (0.68) and Impact of vadose zone media (0.63) parameters is more than other parameters in the study pelly-mianrudan area. The statistical analysis confirms that parameter soil media and topography are the most sensitive to contamination, followed in importance by parameters aquifer medium, vadose zone, recharge, hydraulic conductivity and depth to water.展开更多
The asymmetric reduction of β-keto esters to their corresponding hydroxy alcohols can be performed by employing homogeneous and heterogeneous chemo- and bio-catalysis. This review covers the scope and limitations of ...The asymmetric reduction of β-keto esters to their corresponding hydroxy alcohols can be performed by employing homogeneous and heterogeneous chemo- and bio-catalysis. This review covers the scope and limitations of different catalysts and methodologies that were employed for the reaction and compare between them on the basis of catalytic performance, product separation and catalyst recycling procedure. In general, heterogeneous catalytic systems are advantageous from industrial point of views as they can be easily separated by filtration and re-used. Nickel modified with tartaric acid and sodium bromide was found to be suitable heterogeneous catalyst for the enantioselective hydrogenation, yet its performance is lower than this of homogeneous chiral metal catalysts such as Ru-BINAP. Heterogenization of the chiral complex via immobilization or entrapment using organic and inorganic supports was thus tested. However, though the resulted heterogeneous analogues were highly enantioselective and could be re-used, the activity of the system is often very low compared to homogeneous system due to mass transfer limitations. Alternatively, performing liquid phase hydrogenation under homogeneous conditions, using Ru-BINAP soluble derivatives, yielded high activit5' and enantioselectivity. Product separation and catalysts recycling were facilitated by either extraction of the product with solvent that does not dissolve the complex or by selective filtration of the product. Alternatively, precipitation of the complex at the end of the reaction was also reported.展开更多
Since the 1990s, indigenous people in Taiwan have engaged in tribal councils for the purpose of integrating the tribal authority and the modern administrative system. The establishment of tribal councils provides a co...Since the 1990s, indigenous people in Taiwan have engaged in tribal councils for the purpose of integrating the tribal authority and the modern administrative system. The establishment of tribal councils provides a communicative forum for tribal leaders, village, and the association of community development to make decisions of common tribal affairs. When disasters happen, the internal tribal response strategies and external assistance mechanisms might cooperate through either traditional or modern administrative systems. The research focused on how these organizations, while in interim housing, influenced the reconstruction and rehabilitation after disasters. The research's findings suggested that tribal councils, a pre-existing mechanism, seemed to be an appropriate forum for negotiation and decision-making for tribal affairs.展开更多
Terrain plays a key role in landscape pattern formation, particularly in the transition zones from mountains to plains.Exploring the relationships between terrain characteristics and landscape types in terrain-complex...Terrain plays a key role in landscape pattern formation, particularly in the transition zones from mountains to plains.Exploring the relationships between terrain characteristics and landscape types in terrain-complex areas can help reveal the mechanisms underlying the relationships. In this study, Qihe River Basin, situated in the transition zone from the Taihang Mountains to the North-China Plain, was selected as a case study area. First, the spatial variations in the relief amplitudes(i.e.,high-amplitude terrain undulations) were analyzed. Second, the effects of relief amplitudes on the landscape patterns were indepth investigated from the perspectives of both landscape types and landscape indices. Finally, a logistic regression model was employed to examine the relationships between the landscape patterns and the influencing factors(natural and human) at different relief amplitudes. The results show that with increasing relief amplitude, anthropogenic landscapes gradually give in to natral landscapes. Specifically, human factors normally dominate the gentle areas(e.g., flat areas) in influencing the distribution of landscape types, and natural factors normally dominate the highly-undulating areas(e.g., moderate relief areas). As for the intermediately undulating areas(i.e.,medium relief amplitudes), a combined influence of natural and human factors result in the highest varieties of landscape types. The results also show that in micro-relief areas and small relief areas where natural factors and human factors are more or less equally active,landscape types are affected by a combination of natural and human factors.The combination leads to a high fragmentation and a high diversity of landscape patterns. It seems that appropriate human interferences in these areas can be conducive to enhancing landscape diversity and that inappropriate human interferences can aggravate the problems of landscape fragmentation.展开更多
Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau(LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ...Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau(LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use(LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different-scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor(R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor(C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.展开更多
Based on the discussion of the concept of the developmental state and the socialist developmental state, this article describes and analyzes the development process of China's economy and society since the reform and...Based on the discussion of the concept of the developmental state and the socialist developmental state, this article describes and analyzes the development process of China's economy and society since the reform and opening from the perspective of state transformation, and explores the deep-level causes of the difficulties contemporary China is facing in its economic and social development. It argues that the Chinese state has gradually become a developmental state with a new form, which has played an important role in promoting the development of China's economy and society but meanwhile has brought some negative impacts. China has made many efforts to go beyond the developmental state, and achieved notable success in various aspects since 2002, but there are still many problems, especially when struck by the 2008 world financial crisis; the negative impacts of the developmental state are gradually emerging. Moreover, the Chinese government still tends to sidestep some systemic and structural problems, and some policies are in fact consolidating the dominance of the old system, which will inevitably increase the difficulties for the Chinese state to go beyond the developmental state.展开更多
基金supported by the National "Eleventh Five-Year" Forestry Support Program of China (No2006BAD03A1603)
文摘An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and processing methods are illus-trated. The point cloud results are analyzed in detail. The rescale range analysis method was used to analyze the deformation char-acteristics of the slope. The results show that the trend of slope displacement is stable and that the degree of landslide danger is low. This work indicates that 3-D laser image scanning can supply multi-parameter, high precision real time data over long distances. These data can be used to study the distortion of the slope quickly and accurately.
基金Under the auspices of Supporting Program of the 'Eleventh Five-year Plan' for Science and Technology Research of China (No. 2009BAC61B02)China Postdoctoral Science Foundation Funded Project (No. 20100470561)
文摘Three-River Headwaters (TRH) region involved in this paper refers to the source region of the Changjiang (Yangtze) River, the Huanghe (Yellow) River and the Lancang River in China. Taking the TRH region of the Qing- hai-Tibet Plateau as a case, the annual evapotranspiration (ET) model developed by Zhang et al. (2001) was applied to evaluate mean annual ET in the alpine area, and the response of annual ET to land use change was analyzed. The plant-available water coefficient (w) of Zhang's model was revised by using vegetation-temperature condition index (VTCI) before annual ET was calculated in alpine area. The future land use scenario, an input of ET model, was spa- tially simulated by using the conversion of land use and its effects at small regional extent (CLUE-S) to study the re- sponse of ET to land use change. Results show that the relative errors between the simulated ET and that calculated by using water balance equation were 3.81% and the index of agreement was 0.69. This indicates that Zhang's ET model based on revised plant-available water coefficient is a scientific and practical tool to estimate the annual ET in the al- pine area. The annual ET in 2000 in the study area was 221.2 ram, 11.6 mm more than that in 1980. Average annual ET decreased from southeast to northwest, but the change of annual ET between 1980 and 2000 increased from southeast to northwest. As a vast and sparsely populated area, the population in the TRH region was extremely unbalanced and land use change was concentrated in very small regions. Thus, land use change had little effect on total annual ET in the study area but a great impact on its spatial distribution, and the effect of land use change on ET decreased with in- creasing precipitation. ET was most sensitive to the interconversion between forest and unused land, and was least sen- sitive to the interconversion between cropland and low-covered grassland.
基金CEMI (Centre for Excellence in Mining Innovation) for their funding to support this research
文摘Cooling energy needs, for mines in Northern Ontario, are mainly driven by the mining depth and its operation. Part I of this research focusses on the thermal energy loads in deep mines as a result of the virgin rock temperature, mining operations and climatic conditions. A breakdown of the various heat sources is outlined, for an underground mine producing 3500 tonnes per day of broken rock, taking into consideration the latent and sensible portions of that heat to properly assess the wet bulb global temperature. The resulting thermal loads indicate that cooling efforts would be needed both at surface and underground to maintain the temperature underground within the legal threshold. In winter the air might also have to be heated at surface and cooled underground, to ensure that icing does not occur in the inlet ventilation shaft-the main reason why coolin~ cannot be focussed solely at surface.
文摘AIM: To determine the and clinical features of prevalence, histologic types primary epithelial tumours of the vermiform appendix in a predominantly black population.METHODS: All cases of primary tumours of the appendix identified by review of the histopathology records at the University of the West Indies between January 1987 and June 2007 were selected. Relevant pathologic and clinical data were extracted with supplementation from patient charts where available. Non-epithelial tumours were excluded. The total number of appendectomy specimens over the period was also ascertained.RESULTS: Forty-two primary epithelial tumours were identified out of 6 824 appendectomies yielding a prevalence rate of approximately 0.62%. Welldifferentiated neuroendocrine cell tumours (carcinoids, 47.6%) and benign non-endocrine cell tumours (adenomas, 45.2%) were most common with nearly equal frequency. The median age was 43 years, with no sex predilection. Carcinoid tumours occurred in younger patients (mean age 32 years), with a male-to-female ratio of 1.2:1. A clinical diagnosis of acute appendicitis was the most common reason for appendectomy (57.1%) and was histologically confirmed in 75% (18 of 24) of cases. In total, 16.7% of cases were diagnosed after incidental appendectomy.CONCLUSION: Appendiceal epithelial tumours are rare in our experience, and are represented principally by carcinoid turnours and adenornas. Carcinoid tumours occurred in younger patients but were slightly more common in men than women. Tumours were not suspected clinically and were diagnosed incidentally in specimens submitted for acute appendicitis supporting the need for histological evaluation in all resection specimens.
基金the National Natural Science Foundation of China(No.40771086)National Key Technology R&D Program of China (No.2006BAD09B10)Knowledge Innovation Project of Chinese Academy of Sciences (No.KZCX2-XB2-05-01)
文摘De-farming slope farmland has been an effective measure in recent years to improve environment and prevent soil and water loss on the Loess Plateau.There are different views about the defarming method,and also various de-farming patterns have been put into practice.This paper takes the Yangou Watershed in Shaanxi Province of China as a case for studying the comprehensive benefits of transforming slope farmland to terraces.Based on the day-by-day meteorological data of the Yan'an station in 2005 and the data of terrain features,soil and land use data of the Yangou Watershed,the impact of transforming slope farmland on terraces were simulated and analyzed in aspects of yield increase and water-soil conservation under different topographic conditions with the aid of software WIN-YIELD.Furthermore,an empirical analysis was applied to study the effects of transforming slope farmland to terraces in the Yangou Watershed.The results show that:(1) The bigger the topographic gradient is,the more remarkable benefits it has in yield increase and water-soil conservation.(2) Farmland with slope below 5° could be retained,but farmland with slope above 15° should be converted to forest or grassland as soon as possible.(3) Transforming slope farmland to terraces has the same remarkable effects as the current policy of "Relieving and de-farming" in improving agricultural production conditions,safeguarding food security,raising permanent vegetation coverage rate,and preventing soil and water loss.Besides,it is more cost-effective than the policy of "Relieving and de-farming".It's strongly suggested that the policy of transforming slope farmland to terraces be carried out on the Loess Plateau without delay.
文摘Based on the petroleum processing units of a certain domestic refinery, the authors studied the appropriate cases for processing of Tahe medium gravity crude. The influence of three crude processing cases, including the case for processing of crude slate blended with Tahe medium gravity crude, the case for separate processing and storing of individual crude oils, and the case for flash distillation of Tahe medium gravity crude coupled with separated processing of crude oils, on the products quality, stability of production operation and the overall techno-economic parameters was investigated. The study results have shown that the case for processing crude slate blended with Tahe medium gravity crude could lead to deterioration of the FCC products distribution, dramatic reduction of light distillates, significant surge of sulfur content in FCC naphtha, and increased specific consumption of FCC catalyst, indicating that this case was obviously not suited for processing the Tahe medium gravity crude. The case for separate processing and storing of individual crude oils, however, could increase the aggregate salable products ratio, but the frequent switchover of process streams could cause difficulty and hazards to the stabilization of refining operations, which could not be an ideal processing case. The case for flash distillation of Tahe medium gravity crude coupled with separate processing of crude oils featured the simplicity of process scheme, easiness for modification of process units, easy operation and a slight increase in the aggregate salable products ratio, making itself a suitable case for processing the Tahe medium gravity crude.
文摘In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberration free optical devices. The tip-tilt of facet in a mirror array is produced by digitally controlled line-tilts of rows and columns. It has not only provided a cost-effective designing methodology in optical physics but also led to a much finer precision of 1 mili arc sec or less. As examples of the application of the proposed digitalised optics, two case studies have been given: a 10 m Schmidt telescope (off-axis) and an 8 m Cassegrain telescope (on-axis).
基金Supported by a grant from the Sciences and Technology Foundation of Guangdong Province (No. 73128)
文摘Objective:The aim of the study was to explore the therapeutic efficacy and safety of batroxobin in patients with primary hepatic carcinoma(PHC) and the advantages of transcatheter arterial perfusion of batroxobin combined with transcatheter arterial chemoembolization(TACE).Methods:Forty patients with PHC were randomized into experimental group(transcatheter arterial perfusion of batroxobin combined with TACE treatment,20 patients) and control group(TACE alone group,20 patients).The patients were followed up and the data were recorded,compared and analyzed.Results:(1) Compared with the control group,the FIB level in the experimental group was significantly decreased at the first month after treatment(P < 0.05).(2) The baseline of the tumor was shortened in both groups after the treatment.There was a significant difference between the two groups at different time intervals(P < 0.05).(3) After the treatment,there was a significant difference of progression-free survival(PFS) levels between the two groups(t =2.877,P < 0.05).(4) The incidence of metastasis were 5.0%(1/20) in both groups at 6 months after treatment,and that after one year was 10.0%(2/20) in the experimental group and 25.0%(5/20) in the control group.However,the difference was not significant(χ2 = 0.693,P > 0.05).Conclusion:Batroxobin can rapidly and effectively decrease the FIB level of the PHC cases.Therefore it may be used as an effective and safe adjuvant drug for the treatment of primary hepatic carcinomas.Transcatheter arterial perfusion of batroxobin combined with TACE therapy has advantages in comparison with TACE alone therapy.It could be taken as a new therapeutic regimen in the PHC treatment.
文摘With finite computation precision, digital chaos will lose chaotic characteristic. An efficient perturbance-based algorithm perturbing chaos variable algorithm(PCV) was proposed, which can be regarded as a remedy to digital chaos. After being perturbed, digital chaos systems are able to generate pseudo random sequences with perfect statistical properties and can be used as key stream generators in cryptogram.
文摘Reinforcement bar corrosion depends heavily on environment and the processes used. This study will address galvanic corrosion. Based on a case study of galvanic corrosion in a guyed power transmission tower, experiments using a number of methods were made on a small sample of eight poles chosen for excavation and visual inspection, to assess the various resulting diagnoses. Method that provided the best results both in location and classification of the points was adopted, where corrosion had already begun, considering the concern of finding a non-evasive process. To diagnose the status of the poles inserted in rock, after applying the methods, the main types of corrosion affecting them were listed and classified. With the results, the possible means of preventing and maintaining the structure were presented.
文摘Considering the low average rainfall in the country and the importance of groundwater as a water supply source for drinking and agricultural water sections, water quality condition of groundwater must be controlled and prevented from any contamination. Identifying the vulnerable areas to pollution is one way of prevention. Many models have been offered for this purpose. In this study, a numerical rating scheme, called DRASTIC has been used for evaluating potential for groundwater pollution in pelly-mianrudan plain that is located in northern Lalli city in Khuzestan province. Resulted map obtained in GIS environment shows that the study area has DRASTIC index of 71-150 that is divided to five vulnerable zones namely no significance, very low, low, low to moderate, moderate to high. Maximum groundwater vulnerability correspondent low to medium zone that approximately covers 45 percentage of the study area and other parts on the northwest and center of the study area has high vulnerability. The sensitivity analysis showed that correlation DRASTIC index with net Recharge (0.68) and Impact of vadose zone media (0.63) parameters is more than other parameters in the study pelly-mianrudan area. The statistical analysis confirms that parameter soil media and topography are the most sensitive to contamination, followed in importance by parameters aquifer medium, vadose zone, recharge, hydraulic conductivity and depth to water.
文摘The asymmetric reduction of β-keto esters to their corresponding hydroxy alcohols can be performed by employing homogeneous and heterogeneous chemo- and bio-catalysis. This review covers the scope and limitations of different catalysts and methodologies that were employed for the reaction and compare between them on the basis of catalytic performance, product separation and catalyst recycling procedure. In general, heterogeneous catalytic systems are advantageous from industrial point of views as they can be easily separated by filtration and re-used. Nickel modified with tartaric acid and sodium bromide was found to be suitable heterogeneous catalyst for the enantioselective hydrogenation, yet its performance is lower than this of homogeneous chiral metal catalysts such as Ru-BINAP. Heterogenization of the chiral complex via immobilization or entrapment using organic and inorganic supports was thus tested. However, though the resulted heterogeneous analogues were highly enantioselective and could be re-used, the activity of the system is often very low compared to homogeneous system due to mass transfer limitations. Alternatively, performing liquid phase hydrogenation under homogeneous conditions, using Ru-BINAP soluble derivatives, yielded high activit5' and enantioselectivity. Product separation and catalysts recycling were facilitated by either extraction of the product with solvent that does not dissolve the complex or by selective filtration of the product. Alternatively, precipitation of the complex at the end of the reaction was also reported.
文摘Since the 1990s, indigenous people in Taiwan have engaged in tribal councils for the purpose of integrating the tribal authority and the modern administrative system. The establishment of tribal councils provides a communicative forum for tribal leaders, village, and the association of community development to make decisions of common tribal affairs. When disasters happen, the internal tribal response strategies and external assistance mechanisms might cooperate through either traditional or modern administrative systems. The research focused on how these organizations, while in interim housing, influenced the reconstruction and rehabilitation after disasters. The research's findings suggested that tribal councils, a pre-existing mechanism, seemed to be an appropriate forum for negotiation and decision-making for tribal affairs.
基金supported by the National Basic Research Program of China(Grant No.2015CB452702)the National Natural Science Foundation of China(Grant Nos.41671090&41601091)
文摘Terrain plays a key role in landscape pattern formation, particularly in the transition zones from mountains to plains.Exploring the relationships between terrain characteristics and landscape types in terrain-complex areas can help reveal the mechanisms underlying the relationships. In this study, Qihe River Basin, situated in the transition zone from the Taihang Mountains to the North-China Plain, was selected as a case study area. First, the spatial variations in the relief amplitudes(i.e.,high-amplitude terrain undulations) were analyzed. Second, the effects of relief amplitudes on the landscape patterns were indepth investigated from the perspectives of both landscape types and landscape indices. Finally, a logistic regression model was employed to examine the relationships between the landscape patterns and the influencing factors(natural and human) at different relief amplitudes. The results show that with increasing relief amplitude, anthropogenic landscapes gradually give in to natral landscapes. Specifically, human factors normally dominate the gentle areas(e.g., flat areas) in influencing the distribution of landscape types, and natural factors normally dominate the highly-undulating areas(e.g., moderate relief areas). As for the intermediately undulating areas(i.e.,medium relief amplitudes), a combined influence of natural and human factors result in the highest varieties of landscape types. The results also show that in micro-relief areas and small relief areas where natural factors and human factors are more or less equally active,landscape types are affected by a combination of natural and human factors.The combination leads to a high fragmentation and a high diversity of landscape patterns. It seems that appropriate human interferences in these areas can be conducive to enhancing landscape diversity and that inappropriate human interferences can aggravate the problems of landscape fragmentation.
基金National Natural Science Foundation of China,No.41771207,No.41171069
文摘Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau(LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use(LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different-scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor(R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor(C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.
文摘Based on the discussion of the concept of the developmental state and the socialist developmental state, this article describes and analyzes the development process of China's economy and society since the reform and opening from the perspective of state transformation, and explores the deep-level causes of the difficulties contemporary China is facing in its economic and social development. It argues that the Chinese state has gradually become a developmental state with a new form, which has played an important role in promoting the development of China's economy and society but meanwhile has brought some negative impacts. China has made many efforts to go beyond the developmental state, and achieved notable success in various aspects since 2002, but there are still many problems, especially when struck by the 2008 world financial crisis; the negative impacts of the developmental state are gradually emerging. Moreover, the Chinese government still tends to sidestep some systemic and structural problems, and some policies are in fact consolidating the dominance of the old system, which will inevitably increase the difficulties for the Chinese state to go beyond the developmental state.