BACKGROUND Open ureteric reimplantation by cross trigonal technique described by Cohen is considered a common surgical option for correction of vesicoureteral reflux(VUR). There is a lack of evidence in literature tho...BACKGROUND Open ureteric reimplantation by cross trigonal technique described by Cohen is considered a common surgical option for correction of vesicoureteral reflux(VUR). There is a lack of evidence in literature though for what happens to such kidneys, in the long run, particularly those which are poorly functioning.AIM To assess the long-term outcomes of ureteric reimplantation in poorly functioning kidneys in children with unilateral primary VUR.METHODS Children with unilateral primary VUR and a relative renal function of less than 35% who underwent open or laparoscopic ureteric reimplantation between January 2005 and January 2017 were included in the study. Patients who had a follow up of less than five years were excluded. Preoperative evaluation consisted of a voiding cystourethrogram and Dimercaptosuccinic acid(DMSA) scan. In the follow-up period, patients underwent a diuretic scan at 6 weeks and 6 months.Follow up ultrasound was done for change in grade of hydronephrosis and retrovesical ureteric diameter. Subsequent follow up was done at 6 monthly intervals with evaluation for proteinuria and hypertension and any recurrent urinary tract infection(UTI). For assessment of cortical function, DMSA was repeated annually for 5 years after surgery. A paired-samples t-test was used to test the mean difference of DMSA between pre-post observations.RESULTS During this period, 36 children underwent ureteric reimplantation for unilateral primary VUR. After excluding those with insufficient follow-up, 31 were included in the analysis. Most of the patients were males(n = 26/31, 83.8%). Patient’s age(mean ± SD, range) was 5.21 ± 3.71, 1-18 years. The grades of VUR were grade Ⅱ(1patient), grade Ⅲ(8 patients), grade Ⅳ(10 patients), and grade Ⅴ(12 patients). The pre and postoperative DMSA was 24.064 ± 12.02 and 24.06 ± 10.93, which was almost the same(statistically equal, paired-samples t-test: P = 0.873). The median(range) follow-up duration was 82(60-120)mo. One patient had persistent reflux after surgery(preoperative: grade Ⅳ, postoperative: grade Ⅲ), and the very same patient developed recurrent UTI. The difference in the preoperative and postoperative DRF was less than 10% in 29 patients. In one patient, the DRF decreased by 17%(22% to 05%) while in another patient, the DRF increased by 12%(25% to 37%) after surgery. None of the patients had an increase in scarring after surgery. 15% of patients were hypertensive before surgery and all of them continued to be hypertensive after surgery while none developed hypertension after surgery. None of the patients had significant proteinuria(> 150 mg/d) during the follow-up period.CONCLUSION Children with unilateral primary VUR and poorly functioning kidney maintain the renal function over the long term in most cases. Hypertension and proteinuria do not progress over time in these patients.展开更多
The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were...The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were invited to a private clinic for blood sampling and enzyme analysis. All participants were male farmers of different age groups, and education levels. Occupational parameters indicated that majority of farmers used manual methods for pesticide works. About 130 pesticides are currently used in Gaza. Toxicological symptoms indicated that dizziness, headache, and nausea were dominant among farmers, whereas vomiting abdominal colic and tearing were less dominant. Acetyl Cholinesterase (ACHE) cumulatively inhibited among farmers after work whereas Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) activities were above range after long term exposure. It can be concluded that long term exposure to pesticides may damage liver and kidney cells resulting in hepatic-toxicity and/or nephrotoxicity.展开更多
In this study, the characteristics of the long term discharge of a Terraced Paddy Field Catchment are studied. 2 Kind of Tank Models are proposed and used to simulate the discharge of the catchment. The characteristic...In this study, the characteristics of the long term discharge of a Terraced Paddy Field Catchment are studied. 2 Kind of Tank Models are proposed and used to simulate the discharge of the catchment. The characteristics of the model simulations of the discharge of the catchment are analyzed and compared with those of a forest catchment.展开更多
A new long term integration algorithm is proposed forhigh-dynamic targets, which can resolve the problems of spectrumspread, frequency walk and pseudorandom noise (PRN)code phase curvature caused by the motion of ta...A new long term integration algorithm is proposed forhigh-dynamic targets, which can resolve the problems of spectrumspread, frequency walk and pseudorandom noise (PRN)code phase curvature caused by the motion of targets. This algorithmfirst applies a keystone transform based improved discretepolynomial-phase transform (KT-IDPT) to estimate the Dopplerchirp rate. Then, based on the estimated Doppler chirp rate,dechirping and envelope translation are performed on the partialcorrelation results to correct the spectrum spread and the codephase curvature. The simulation results demonstrate that the proposedmethod has low integration loss and computational burden.展开更多
Introduction: Acne vulgaris and acne scarring are prevalent conditions that can have a negative effect on a patient’s quality of life. Fractional radiofrequency technologies have been shown to be clinically safe and ...Introduction: Acne vulgaris and acne scarring are prevalent conditions that can have a negative effect on a patient’s quality of life. Fractional radiofrequency technologies have been shown to be clinically safe and effective in managing acne scars through dermal remodeling without causing direct damage to the epidermis. In a recently published study, we presented our clinical and histological results in the treatment of patients with active acne and acne related scarring using a Fractional RF (FRF) device. In the current article we demonstrate long term follow-up results, up to two years post last fractional treatment. Methods: Four out of the eight patients who completed a four treatment regimen were invited for long term follow-up visit to document treatment results. In some cases, touch-up treatments were conducted to optimize clinical results. Results: Patients demonstrated significant improvement of acne lesions, acne scarring, pores and skin texture. Long term photos demonstrated that clinical improvement progressed with time. Conclusion: The current study further supports the previous findings that FRF is a safe and effective treatment modality for active acne and acne related scars. Treatment protocol can be customized according to patient needs and clinical results last for long term.展开更多
Numerical modelling of coastal morphology is a complex and sometimes unrewarding exercise and often not yielding tangible results. Typically, the underlying drivers of morphology are not properly accounted for in nume...Numerical modelling of coastal morphology is a complex and sometimes unrewarding exercise and often not yielding tangible results. Typically, the underlying drivers of morphology are not properly accounted for in numerical models. Such inaccuracies combined with a paucity of validation data create a difficulty for coastal planners/engineers who are required to interpret such morphological models to develop coastal management strategies. This study develops an approach to long term morphological modelling of a barrier beach system that includes the findings of over 10 years of coastal monitoring on a dynamic coastal system. The novel approach to predicting the long term evolution of the area combines a mix of short term hydrodynamic monitoring and long term morphological modelling to predict future changes in a breached barrier system. A coupled wave, wind, hydrodynamic and sediment transport numerical model was used to predict the coastal evolution in the dynamic barrier beach system of Inner Dingle Bay, Co. Kerry, Ireland. The modelling approach utilizes the schematisation of inputs to reflect observed trends. The approach is subject to two stages of validation both quantitative and qualitative. The study highlights the importance of considering all the parameters responsible for driving coastal evolution and the necessity to have long term monitoring results for trend based validation.展开更多
The earthquakes with Ms≥6.0 are often gathered into belts or clusters and are roughly consistent with tectonic structure trends in the Sichuan-Yunnan (Chuan-Dian) region. The middle south part(98°-106°E, 21...The earthquakes with Ms≥6.0 are often gathered into belts or clusters and are roughly consistent with tectonic structure trends in the Sichuan-Yunnan (Chuan-Dian) region. The middle south part(98°-106°E, 21°-34°N) of South-North Seismic Zone can be zoned into seven small areas. There all were strong quakes with M_s≥7.0 historically in each small area. Ten earthquakes with M_s≥7.0 have occurred in this region since 1970 and they appeared in five small areas respectively. The relationships between occurrence-time and cumulative frequencies of strong quakes in these five areas are shown to be an exponential distribution or power function. By examining the inner coincidence it is indicated that these relationships are of definite significance to mid-long term macroseismic prediction of each area.展开更多
Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M_≥6 occurred means more elastic energy store and speedy energy accumulation there. When...Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M_≥6 occurred means more elastic energy store and speedy energy accumulation there. When an active period of big earthquake activity appeared in wide region, in the place where earthquake (M_≥6) occurred in the past quiet period, the big earthquake with magnitude of 7 or more often occur there. We call the above-mentioned judgement for predicting big earthquake the 'criterion of activity in quiescence'. The criterion is relatively effective for predicting location of big earthquake. In general, error of predicting epicenter is no more than 100 km. According to the criterion, we made successfully a middle-term prediction on the 1996 Lijiang earthquake in Yunnan Province, the error of predicted location is about 50 km. Besides, the 1994 Taiwan strait earthquake (M_s=7.3), the 1995 Yunnan-Myanmar boundary earthquake (M_s=7.2) and the Mani earthquake (M_s=7.9) in north Tibet are accordant with the retrospective predictions by the 'criterion of activity in quiescence'. The windows of 'activity in quiescence' identified statistically by us are 1940-1945, 1958-1961 and 1979-1986. Using the 'criterion of activity in quiescence' to predict big earthquake in the mainland of China,the earthquake defined by 'activity in quiescence' has magnitude of 6 or more; For the Himalayas seismic belt, the Pacific seismic belt and the north-west boundary seismic belt of Xinjiang, the earthquake defined by 'activity in quiescence' has magnitude of 7, which is corresponding to earthquake with magnitude of much more than 7 in future. For the regions where there are not tectonically and historically a possibility of occurring big earthquake (M_s=7), the criterion of activity in quiescence is not effective.展开更多
The leading role of undertaking most part of business activities bytapping fund through public listing for Guangdong Enterprises(Holdings)Limited.(here-in-after called GDE)is Played by one of its affiliate,GuangdongIn...The leading role of undertaking most part of business activities bytapping fund through public listing for Guangdong Enterprises(Holdings)Limited.(here-in-after called GDE)is Played by one of its affiliate,GuangdongInvestment Limited (Here-in-after called GDI).In ten years of activeties,GDIPolicy makers deeply felt that their supreme responsibility was to create thebiggest wealth at present and in the future for the property owner,to achievethe biggest increase of property value,and in the meantime to contribute a bitfor the continuous progress of society.展开更多
IN the heart of the Democratic Republic of Congo (DRC) lies Virunga National Park, a UNESCO Heritage Site that boasts the title of Africa's oldest national park. At 7,800 square km, the park contains the most biodi...IN the heart of the Democratic Republic of Congo (DRC) lies Virunga National Park, a UNESCO Heritage Site that boasts the title of Africa's oldest national park. At 7,800 square km, the park contains the most biodiversity of any part of Africa and is home to the greatly endangered mountain gorilla.展开更多
China's ongoing engagement with Africa is a major success story and constitutes an excellent example of development cooperation and interdependence toward common economic prosperity. The China-Africa trade relation- ...China's ongoing engagement with Africa is a major success story and constitutes an excellent example of development cooperation and interdependence toward common economic prosperity. The China-Africa trade relation- ship is important for China's ongoing eco- nomic growth, while commodity exports to China provide a foundation for economic development across the Mrican continent. A strong complementarity between China and Africa, grounded on respective stages of economic development, gives Africa a unique opportunity to export commodities to a rapidly expanding Chinese market. complementarity has seen China-Africa trade grow from only $10 billion in 2000 to over $170 billion in 2017.展开更多
Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec...Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec. 31st,2010 were analyzed retrospectively. The pa-展开更多
在中长期水火发电调度中考虑检修计划的影响是目前中长期水火发电调度面临的难题。利用现代整数代数建模技术,建立发电计划和检修计划协调优化的多场景调度模型。在该模型中,鉴于设备检修计划的连续性,在预测场景树的基础上,将场景...在中长期水火发电调度中考虑检修计划的影响是目前中长期水火发电调度面临的难题。利用现代整数代数建模技术,建立发电计划和检修计划协调优化的多场景调度模型。在该模型中,鉴于设备检修计划的连续性,在预测场景树的基础上,将场景节点划分成不同的场景,通过节点和场景关联矩阵,实现多场景下设备检修模型的构建。同时,鉴于中长期调度计划中发电计划和检修计划对时段间隔要求的不同,分别设置电量相关节点和电力相关节点,实现中长期发电计划和检修计划的协调。上述模型是一个大规模混合整数线性规划(mixed integer linear programming,MILP)问题,采用商用MILP求解器进行求解。大规模实际水火电系统的实例分析结果表明,所提模型和方法是可行、有效的。展开更多
Isobutane alkylation with 2-butene to produce high-quality gasoline was catalyzed by Nmethylacetamide(NMA)-AlCl3 based ionic liquid(IL) analog with a NMA/AlCl3 molar ratio of 0.75 and CuCl modification,which was marke...Isobutane alkylation with 2-butene to produce high-quality gasoline was catalyzed by Nmethylacetamide(NMA)-AlCl3 based ionic liquid(IL) analog with a NMA/AlCl3 molar ratio of 0.75 and CuCl modification,which was marked as CuCl-modified 0.75 NMA-1.0 AlCl3.The long-term experiment was carried out in the autoclave operated in continuous mode to investigate the distribution of alkylate under different experimental nodes.The result indicated that the long-term alkylation was divided into three stages:rising,stable,and descending regions.C8 selectivity and molar ratio of trimethylpentanes(TMPs) to dimethylhexanes(DMHs) reached the highest level in the stable region,and research octane number(RON) of alkylate was as high as 97.Anionic Al species([AlbCl7]^-,[A1 CuC15]^-) and cationic Al species([AlCl2 L]^+) from IL analog as two active Lewis acidic species played a catalytic role in the long-term alkylation,whereas the neutral Al species did not participate into the alkylation.Moreover,the structure of CuCl-modified 0.75 NMA-1.0 AlCl3 was destroyed after the deactivation,and CuCl was enriched in the CD2 Cl2-insoluble substance,resulting in a decreasing TMP/DMH ratio.The catalytic lifetime of IL analog was similar with CuCl-modified 0.55 Et3 NHCl-1.0 AlCl3 IL,but IL analog had a lower cost.展开更多
It is necessary to study the tropical western Pacific SST in association with variations of other parts of the globe. Two basic compositions are revealed of long-term variation in SST over three major tropical oceans ...It is necessary to study the tropical western Pacific SST in association with variations of other parts of the globe. Two basic compositions are revealed of long-term variation in SST over three major tropical oceans since the 1950’s (linear warming and El Ni?o-La Ni?a oscillations) and typical patterns with which they are displayed over the oceans are compared. On the basis of it, difference in long-term variation of SST over western, central and eastern tropical Pacific is analyzed in details. It is pointed out that the El Ni?o-La Ni?a oscillations are relatively weak in the long-term variation of SST in the tropical western Pacific and linear warming trend there is replaced by interdecadal oscillations. Further understanding of the peculiarity over the region helps improve short-term climatic predictions in China.展开更多
Interfacial dislocations found in single crystal superalloys after long term thermal aging have an important effect on mechanical properties. Long term thermal aging tests for DD5 single crystal superalloy were carrie...Interfacial dislocations found in single crystal superalloys after long term thermal aging have an important effect on mechanical properties. Long term thermal aging tests for DD5 single crystal superalloy were carried out at 1,100 ℃ for 20, 100, 200, 500 and 1000 h, and then cooled by air. The effect of long term thermal aging on the dislocation networks at the γ/γ' interfaces was investigated by FE-SEM. Results showed that during the long term thermal aging at 1,100 ℃, misfit dislocations formed firstly and then reorientation in the(001) interfacial planes occurred. Different types of square or rectangular dislocation network form by dislocation reaction. Square dislocation networks consisting of four groups of dislocations can transform into octagonal dislocation networks, and then form another square dislocation network by dislocation reaction. Rectangular dislocation networks can also transform into hexagonal dislocation networks. The interfacial dislocation networks promote the γ' phase rafting process. The dislocation networks spacings become smaller and smaller, leading to the effective lattice misfit increasing from-0.10% to-0.32%.展开更多
Tests were carried out on 8 self-compacting reinforced concrete(SCC) beams and 4 normal reinforced concrete beams. The effects of mode of consolidation,load level,reinforcing ratio and structural type on long term beh...Tests were carried out on 8 self-compacting reinforced concrete(SCC) beams and 4 normal reinforced concrete beams. The effects of mode of consolidation,load level,reinforcing ratio and structural type on long term behavior of SCC were investigated. Under the same environmental conditions,the shrinkage-time curve of self-compacting concrete beam is very similar to that of normal concrete beam. For both self-compacting reinforced concrete beams and normal reinforced concrete beams,the rate of shrinkage at early stages is higher,the shrinkage strain at 2 months is about 60% of the maximum value at one year. The shrinkage strain of self-compacting reinforced concrete beam after one year is about 450×10-6. Creep deflection of self-compacting reinforced concrete beam decreases as the tensile reinforcing ratio increases. The deflection creep coefficient of self-compacting reinforced concrete beam after one and a half year is about 1.6,which is very close to that of normal reinforced concrete beams cast with vibration. Extra cautions considering shrinkage and creep behavior are not needed for the use of SCC in engineering practices.展开更多
文摘BACKGROUND Open ureteric reimplantation by cross trigonal technique described by Cohen is considered a common surgical option for correction of vesicoureteral reflux(VUR). There is a lack of evidence in literature though for what happens to such kidneys, in the long run, particularly those which are poorly functioning.AIM To assess the long-term outcomes of ureteric reimplantation in poorly functioning kidneys in children with unilateral primary VUR.METHODS Children with unilateral primary VUR and a relative renal function of less than 35% who underwent open or laparoscopic ureteric reimplantation between January 2005 and January 2017 were included in the study. Patients who had a follow up of less than five years were excluded. Preoperative evaluation consisted of a voiding cystourethrogram and Dimercaptosuccinic acid(DMSA) scan. In the follow-up period, patients underwent a diuretic scan at 6 weeks and 6 months.Follow up ultrasound was done for change in grade of hydronephrosis and retrovesical ureteric diameter. Subsequent follow up was done at 6 monthly intervals with evaluation for proteinuria and hypertension and any recurrent urinary tract infection(UTI). For assessment of cortical function, DMSA was repeated annually for 5 years after surgery. A paired-samples t-test was used to test the mean difference of DMSA between pre-post observations.RESULTS During this period, 36 children underwent ureteric reimplantation for unilateral primary VUR. After excluding those with insufficient follow-up, 31 were included in the analysis. Most of the patients were males(n = 26/31, 83.8%). Patient’s age(mean ± SD, range) was 5.21 ± 3.71, 1-18 years. The grades of VUR were grade Ⅱ(1patient), grade Ⅲ(8 patients), grade Ⅳ(10 patients), and grade Ⅴ(12 patients). The pre and postoperative DMSA was 24.064 ± 12.02 and 24.06 ± 10.93, which was almost the same(statistically equal, paired-samples t-test: P = 0.873). The median(range) follow-up duration was 82(60-120)mo. One patient had persistent reflux after surgery(preoperative: grade Ⅳ, postoperative: grade Ⅲ), and the very same patient developed recurrent UTI. The difference in the preoperative and postoperative DRF was less than 10% in 29 patients. In one patient, the DRF decreased by 17%(22% to 05%) while in another patient, the DRF increased by 12%(25% to 37%) after surgery. None of the patients had an increase in scarring after surgery. 15% of patients were hypertensive before surgery and all of them continued to be hypertensive after surgery while none developed hypertension after surgery. None of the patients had significant proteinuria(> 150 mg/d) during the follow-up period.CONCLUSION Children with unilateral primary VUR and poorly functioning kidney maintain the renal function over the long term in most cases. Hypertension and proteinuria do not progress over time in these patients.
文摘The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were invited to a private clinic for blood sampling and enzyme analysis. All participants were male farmers of different age groups, and education levels. Occupational parameters indicated that majority of farmers used manual methods for pesticide works. About 130 pesticides are currently used in Gaza. Toxicological symptoms indicated that dizziness, headache, and nausea were dominant among farmers, whereas vomiting abdominal colic and tearing were less dominant. Acetyl Cholinesterase (ACHE) cumulatively inhibited among farmers after work whereas Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) activities were above range after long term exposure. It can be concluded that long term exposure to pesticides may damage liver and kidney cells resulting in hepatic-toxicity and/or nephrotoxicity.
文摘In this study, the characteristics of the long term discharge of a Terraced Paddy Field Catchment are studied. 2 Kind of Tank Models are proposed and used to simulate the discharge of the catchment. The characteristics of the model simulations of the discharge of the catchment are analyzed and compared with those of a forest catchment.
基金supported by the Beijing Natural Science Foundation(4164097)the Chinese Postdoctoral Science Foundation(2016M591226)
文摘A new long term integration algorithm is proposed forhigh-dynamic targets, which can resolve the problems of spectrumspread, frequency walk and pseudorandom noise (PRN)code phase curvature caused by the motion of targets. This algorithmfirst applies a keystone transform based improved discretepolynomial-phase transform (KT-IDPT) to estimate the Dopplerchirp rate. Then, based on the estimated Doppler chirp rate,dechirping and envelope translation are performed on the partialcorrelation results to correct the spectrum spread and the codephase curvature. The simulation results demonstrate that the proposedmethod has low integration loss and computational burden.
文摘Introduction: Acne vulgaris and acne scarring are prevalent conditions that can have a negative effect on a patient’s quality of life. Fractional radiofrequency technologies have been shown to be clinically safe and effective in managing acne scars through dermal remodeling without causing direct damage to the epidermis. In a recently published study, we presented our clinical and histological results in the treatment of patients with active acne and acne related scarring using a Fractional RF (FRF) device. In the current article we demonstrate long term follow-up results, up to two years post last fractional treatment. Methods: Four out of the eight patients who completed a four treatment regimen were invited for long term follow-up visit to document treatment results. In some cases, touch-up treatments were conducted to optimize clinical results. Results: Patients demonstrated significant improvement of acne lesions, acne scarring, pores and skin texture. Long term photos demonstrated that clinical improvement progressed with time. Conclusion: The current study further supports the previous findings that FRF is a safe and effective treatment modality for active acne and acne related scars. Treatment protocol can be customized according to patient needs and clinical results last for long term.
文摘Numerical modelling of coastal morphology is a complex and sometimes unrewarding exercise and often not yielding tangible results. Typically, the underlying drivers of morphology are not properly accounted for in numerical models. Such inaccuracies combined with a paucity of validation data create a difficulty for coastal planners/engineers who are required to interpret such morphological models to develop coastal management strategies. This study develops an approach to long term morphological modelling of a barrier beach system that includes the findings of over 10 years of coastal monitoring on a dynamic coastal system. The novel approach to predicting the long term evolution of the area combines a mix of short term hydrodynamic monitoring and long term morphological modelling to predict future changes in a breached barrier system. A coupled wave, wind, hydrodynamic and sediment transport numerical model was used to predict the coastal evolution in the dynamic barrier beach system of Inner Dingle Bay, Co. Kerry, Ireland. The modelling approach utilizes the schematisation of inputs to reflect observed trends. The approach is subject to two stages of validation both quantitative and qualitative. The study highlights the importance of considering all the parameters responsible for driving coastal evolution and the necessity to have long term monitoring results for trend based validation.
文摘The earthquakes with Ms≥6.0 are often gathered into belts or clusters and are roughly consistent with tectonic structure trends in the Sichuan-Yunnan (Chuan-Dian) region. The middle south part(98°-106°E, 21°-34°N) of South-North Seismic Zone can be zoned into seven small areas. There all were strong quakes with M_s≥7.0 historically in each small area. Ten earthquakes with M_s≥7.0 have occurred in this region since 1970 and they appeared in five small areas respectively. The relationships between occurrence-time and cumulative frequencies of strong quakes in these five areas are shown to be an exponential distribution or power function. By examining the inner coincidence it is indicated that these relationships are of definite significance to mid-long term macroseismic prediction of each area.
基金State Natural Science Foundation of China!(49674210).
文摘Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M_≥6 occurred means more elastic energy store and speedy energy accumulation there. When an active period of big earthquake activity appeared in wide region, in the place where earthquake (M_≥6) occurred in the past quiet period, the big earthquake with magnitude of 7 or more often occur there. We call the above-mentioned judgement for predicting big earthquake the 'criterion of activity in quiescence'. The criterion is relatively effective for predicting location of big earthquake. In general, error of predicting epicenter is no more than 100 km. According to the criterion, we made successfully a middle-term prediction on the 1996 Lijiang earthquake in Yunnan Province, the error of predicted location is about 50 km. Besides, the 1994 Taiwan strait earthquake (M_s=7.3), the 1995 Yunnan-Myanmar boundary earthquake (M_s=7.2) and the Mani earthquake (M_s=7.9) in north Tibet are accordant with the retrospective predictions by the 'criterion of activity in quiescence'. The windows of 'activity in quiescence' identified statistically by us are 1940-1945, 1958-1961 and 1979-1986. Using the 'criterion of activity in quiescence' to predict big earthquake in the mainland of China,the earthquake defined by 'activity in quiescence' has magnitude of 6 or more; For the Himalayas seismic belt, the Pacific seismic belt and the north-west boundary seismic belt of Xinjiang, the earthquake defined by 'activity in quiescence' has magnitude of 7, which is corresponding to earthquake with magnitude of much more than 7 in future. For the regions where there are not tectonically and historically a possibility of occurring big earthquake (M_s=7), the criterion of activity in quiescence is not effective.
文摘The leading role of undertaking most part of business activities bytapping fund through public listing for Guangdong Enterprises(Holdings)Limited.(here-in-after called GDE)is Played by one of its affiliate,GuangdongInvestment Limited (Here-in-after called GDI).In ten years of activeties,GDIPolicy makers deeply felt that their supreme responsibility was to create thebiggest wealth at present and in the future for the property owner,to achievethe biggest increase of property value,and in the meantime to contribute a bitfor the continuous progress of society.
文摘IN the heart of the Democratic Republic of Congo (DRC) lies Virunga National Park, a UNESCO Heritage Site that boasts the title of Africa's oldest national park. At 7,800 square km, the park contains the most biodiversity of any part of Africa and is home to the greatly endangered mountain gorilla.
文摘China's ongoing engagement with Africa is a major success story and constitutes an excellent example of development cooperation and interdependence toward common economic prosperity. The China-Africa trade relation- ship is important for China's ongoing eco- nomic growth, while commodity exports to China provide a foundation for economic development across the Mrican continent. A strong complementarity between China and Africa, grounded on respective stages of economic development, gives Africa a unique opportunity to export commodities to a rapidly expanding Chinese market. complementarity has seen China-Africa trade grow from only $10 billion in 2000 to over $170 billion in 2017.
文摘Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec. 31st,2010 were analyzed retrospectively. The pa-
文摘在中长期水火发电调度中考虑检修计划的影响是目前中长期水火发电调度面临的难题。利用现代整数代数建模技术,建立发电计划和检修计划协调优化的多场景调度模型。在该模型中,鉴于设备检修计划的连续性,在预测场景树的基础上,将场景节点划分成不同的场景,通过节点和场景关联矩阵,实现多场景下设备检修模型的构建。同时,鉴于中长期调度计划中发电计划和检修计划对时段间隔要求的不同,分别设置电量相关节点和电力相关节点,实现中长期发电计划和检修计划的协调。上述模型是一个大规模混合整数线性规划(mixed integer linear programming,MILP)问题,采用商用MILP求解器进行求解。大规模实际水火电系统的实例分析结果表明,所提模型和方法是可行、有效的。
基金Supported by the National Natural Science Foundation of China(No.21802047)the Scientific Research Funds of Huaqiao University(No.600005-Z17Y0073)
文摘Isobutane alkylation with 2-butene to produce high-quality gasoline was catalyzed by Nmethylacetamide(NMA)-AlCl3 based ionic liquid(IL) analog with a NMA/AlCl3 molar ratio of 0.75 and CuCl modification,which was marked as CuCl-modified 0.75 NMA-1.0 AlCl3.The long-term experiment was carried out in the autoclave operated in continuous mode to investigate the distribution of alkylate under different experimental nodes.The result indicated that the long-term alkylation was divided into three stages:rising,stable,and descending regions.C8 selectivity and molar ratio of trimethylpentanes(TMPs) to dimethylhexanes(DMHs) reached the highest level in the stable region,and research octane number(RON) of alkylate was as high as 97.Anionic Al species([AlbCl7]^-,[A1 CuC15]^-) and cationic Al species([AlCl2 L]^+) from IL analog as two active Lewis acidic species played a catalytic role in the long-term alkylation,whereas the neutral Al species did not participate into the alkylation.Moreover,the structure of CuCl-modified 0.75 NMA-1.0 AlCl3 was destroyed after the deactivation,and CuCl was enriched in the CD2 Cl2-insoluble substance,resulting in a decreasing TMP/DMH ratio.The catalytic lifetime of IL analog was similar with CuCl-modified 0.55 Et3 NHCl-1.0 AlCl3 IL,but IL analog had a lower cost.
文摘It is necessary to study the tropical western Pacific SST in association with variations of other parts of the globe. Two basic compositions are revealed of long-term variation in SST over three major tropical oceans since the 1950’s (linear warming and El Ni?o-La Ni?a oscillations) and typical patterns with which they are displayed over the oceans are compared. On the basis of it, difference in long-term variation of SST over western, central and eastern tropical Pacific is analyzed in details. It is pointed out that the El Ni?o-La Ni?a oscillations are relatively weak in the long-term variation of SST in the tropical western Pacific and linear warming trend there is replaced by interdecadal oscillations. Further understanding of the peculiarity over the region helps improve short-term climatic predictions in China.
基金supported by the National Natural Science Foundation of China(Grant No.:50901046)
文摘Interfacial dislocations found in single crystal superalloys after long term thermal aging have an important effect on mechanical properties. Long term thermal aging tests for DD5 single crystal superalloy were carried out at 1,100 ℃ for 20, 100, 200, 500 and 1000 h, and then cooled by air. The effect of long term thermal aging on the dislocation networks at the γ/γ' interfaces was investigated by FE-SEM. Results showed that during the long term thermal aging at 1,100 ℃, misfit dislocations formed firstly and then reorientation in the(001) interfacial planes occurred. Different types of square or rectangular dislocation network form by dislocation reaction. Square dislocation networks consisting of four groups of dislocations can transform into octagonal dislocation networks, and then form another square dislocation network by dislocation reaction. Rectangular dislocation networks can also transform into hexagonal dislocation networks. The interfacial dislocation networks promote the γ' phase rafting process. The dislocation networks spacings become smaller and smaller, leading to the effective lattice misfit increasing from-0.10% to-0.32%.
基金Project(50278097) supported by the National Natural Science Foundation of China
文摘Tests were carried out on 8 self-compacting reinforced concrete(SCC) beams and 4 normal reinforced concrete beams. The effects of mode of consolidation,load level,reinforcing ratio and structural type on long term behavior of SCC were investigated. Under the same environmental conditions,the shrinkage-time curve of self-compacting concrete beam is very similar to that of normal concrete beam. For both self-compacting reinforced concrete beams and normal reinforced concrete beams,the rate of shrinkage at early stages is higher,the shrinkage strain at 2 months is about 60% of the maximum value at one year. The shrinkage strain of self-compacting reinforced concrete beam after one year is about 450×10-6. Creep deflection of self-compacting reinforced concrete beam decreases as the tensile reinforcing ratio increases. The deflection creep coefficient of self-compacting reinforced concrete beam after one and a half year is about 1.6,which is very close to that of normal reinforced concrete beams cast with vibration. Extra cautions considering shrinkage and creep behavior are not needed for the use of SCC in engineering practices.