1 Introduction Massive tungsten-tin,rare and rare earth metals ore deposits were formed with the widespread granite magmatic activity in early Yanshanian period in the eastern Nanling region.Recent studies indicate th...1 Introduction Massive tungsten-tin,rare and rare earth metals ore deposits were formed with the widespread granite magmatic activity in early Yanshanian period in the eastern Nanling region.Recent studies indicate that the Yanshanian highly differentiated-granite formation is closely related to the deposits of tungsten and tin,rare and rare earth metals mineralization in the展开更多
With the recent development of high entropy materials, an alternative approach to develop advanced functional materials with distinctive properties that show improved values compared to conventional materials has been...With the recent development of high entropy materials, an alternative approach to develop advanced functional materials with distinctive properties that show improved values compared to conventional materials has been provided. The high entropy concept was later successfully transferred to metal fluorides and high entropy fluorides(HEFs) were successfully synthesized. Owing to their high theoretical specific capacities in energy storage applications, HEFs were utilized as cathode materials for lithiumion batteries(LIBs) and their underlying storage mechanisms were investigated. Instead of a step-bystep reduction of each individual metal cation, the HEFs seem to exhibit a single-step reduction process,indicating a solid solution compound instead of merely a mixture of different metal fluorides. It was also observed that the electrochemical behavior of the HEFs depends on each individual incorporated element. Therefore, by altering the elemental composition, new materials that exhibit improved electrochemical properties can be designed. Remarkably, HEFs with seven incorporated metal elements exhibited a better cycling stability as well as a lower hysteresis compared to binary metal fluorides.These findings offer new guidelines for material design and tailoring towards high performance LIBs.展开更多
Soil aggregate stability,as an important indicator of soil functions,may be affected by seasonal freezing and thawing(SFT)and land use in high cold and wet regions.Therefore,comprehensive understanding the effects of ...Soil aggregate stability,as an important indicator of soil functions,may be affected by seasonal freezing and thawing(SFT)and land use in high cold and wet regions.Therefore,comprehensive understanding the effects of SFT on aggregate stability in orchards during winter and spring is crucial to develop appropriate management strategies that can effectively alleviate the degradation of soil quality to ensure sustainable development of orchard ecosystems.To determine the mechanism of degradation in orchard soil quality,the effects of SFT on the stability of water-stable aggregates were examined in apple-pear orchards(Pyrus ussuriensis var.ovoidea)of four different ages(11,25,40,and 63 yr)on 0 to 5%slopes before freezing and after thawing from October 2015 to June 2016 in Longjing City,Yanbian Prefecture,Northeast China,involving a comparison of planted versus adjacent uncultivated lands(control).Soil samples were collected to investigate water-stable aggregate stability in three incremental soil layers(0–20,20–40 and 40–60 cm).In the same samples,iron oxide,organic matter,and clay contents of the soil were also determined.Results showed that the destructive influences of SFT on water-stable aggregates were more pronounced with the increased orchards ages,and SFT exerted severe effects on water-stable aggregates of older orchards(40 and 63 yr)than juvenile orchards.Undergoing SFT,the soil instability index and the percentage of aggregate destruction increased by mean 0.15 mm and 1.86%,the degree of aggregation decreased by mean 1.32%,and the erosion resistance weakened,which consequently led to aggregate stability decreased.In addition,soil free,amorphous,and crystalline iron oxide as well as soil organic matter and clay contents are all important factors affecting the stability of water-stable aggregates,and their changes in their contents were consistent with those in the stability of water-stable aggregates.The results of this study suggest that long-term planting fruit trees can exacerbate the damaging effects of SFT on aggregate stability and further soil erosion increases and nutrient losses in an orchard,which hider sustainable use of soil and the productivity orchards.展开更多
The aim of this study was to investigate the effects of high dietary fluoride (F) on serum biochemistry and oxidative damage in broiler chickens. 280 one-day-old healthy avian broiler chickens were randomly allotted i...The aim of this study was to investigate the effects of high dietary fluoride (F) on serum biochemistry and oxidative damage in broiler chickens. 280 one-day-old healthy avian broiler chickens were randomly allotted into four equal groups and fed with a corn-soybean basal diet containing 22.6 mg·F/kg (control group) or same basal diets supplemented with 400, 800, and 1200 mg·F/kg (high F groups I, II, and III) in the form of sodium fluoride for 42 days. At 42 days of age, the serum F content was markedly higher in the three high F groups than that in the control group. From 28 to 42 days of age, the contents of serum total protein (TP) and albumin (ALB) were significantly lower in the three high F groups. From 14 to 42 days of age, the activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT) and the creatinine (Crea) contents in the serum showed a marked increase in the three high F groups;aspartate aminotransferase (AST) activity and uric acid (Ua) content were significantly increased, and a significant increase in the content of malondialdehyde (MDA) along with marked decreases in the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), catalase (CAT), the glutathione (GSH) content and the ability to inhibit hydroxyl radical were observed in the high F groups II and III. In conclusion, F has accumulated in the blood circulatory system and dietary F in the range of 800 - 1200 mg/kg could significantly induce abnormalities of bone, liver and kidney, inhibit the synthesis of protein, enhance lipid peroxidation and disturb the antioxidative system of broiler chickens.展开更多
Thirty-two Wistar rats were divided randomly into four groups of eight with six females and two males in each group. The rats were exposed to high fluoride drinking water (45 mg F- L-1 from 100 mg NaF L-1), low dietar...Thirty-two Wistar rats were divided randomly into four groups of eight with six females and two males in each group. The rats were exposed to high fluoride drinking water (45 mg F- L-1 from 100 mg NaF L-1), low dietary iodine (0.0855 mg kg-1), or both together in order to assess the effects of these three regimens on the thyroid function of the offspring rats. After the animal model was established, the offspring rats were bred and 10-, 20-, 30-, 60-, and 90-d-old rats were used for the experiment. The treatments for the offspring rats were the same as those of their parents. In comparison with control rats, the relative thyroid glands were changed by three regimens, but the mean values of thyroid weight in the experimental groups saw no marked difference. Serum TT3 levels were increased in all stages in the low iodine (LI) group. In the high fluoride (HiF) group, increase in TT3 levels was observed except in 20-d-old rats. Decrease in TT3 at 20- and 90-d and increase in TT3 at 30- and 60-d were found in HiF+LI group. Serum TT4 levels first saw an increase, and then dropped in the LI and HiF+LI group. However, an increase in TT4 was found in the HiF group. The levels of TSH in serum rocketed at d 20, and then dropped in the next stages in experimental groups. The results suggested that thyroid disorder could be induced by high flroride in drinking water, low iodine diet, or both of them. Exposure time to fluoride or low iodine diet was one of the important factors that fluoride can induce the development of thyroid dyfunction.展开更多
Grain number per spike(GNPS) is a major factor in wheat yield breeding.A new wheat germplasm Pubing 3504 shows superior features in spike traits.To elucidate the genetic basis of spike and yield related traits in Pubi...Grain number per spike(GNPS) is a major factor in wheat yield breeding.A new wheat germplasm Pubing 3504 shows superior features in spike traits.To elucidate the genetic basis of spike and yield related traits in Pubing 3504,282 F2:3 families were generated from the cross Pubing 3504×Jing 4839,and seven spike and yield related traits,including GNPS,spike length(SL),kernel number per spikelet(KPS),spikelet number per spike(SNS),thousand-grain weight(TGW),spike number per plant(SNP),and plant height(HT) were investigated.Correlation analysis indicated significant positive correlations between GNPS and spike-related traits,including KPS,SNS,and SL,especially KPS.A genetic map was constructed using 190 polymorphic simple sequence repeat(SSR),expressed sequence tag(EST)-SSR,and sequencetagged-site(STS) markers.For the seven traits measured,a total of 37 quantitative trait loci(QTLs) in a single-environment analysis and 25 QTLs in a joint-environment analysis were detected.Additive effects of 70.3%(in a single environment) and 57.6%(in a joint environment) of the QTLs were positively contributed by Pubing 3504 alleles.Five important genomic regions on chromosomes 1 A,4 A,4 B,2 D,and 4 D could be stably detected in different environments.Among these regions,the marker interval Xmag834–Xbarc83 on the short arm of chromosome 1 A was a novel important genomic region that included QTLs controlling GNPS,KPS,SNS,TGW,and SNP with stable environmental repeatability.This genomic region can improve the spike trait and may play a key role in improving wheat yield in the future.We deduced that this genomic region was vital to the high GNPS of Pubing 3504.展开更多
In this study, the current status for breast diseases in a region with high-incidence of cervical cancer were epidemiologically investigated. From March to August, 2009, 17618 women, from Wufeng area of Hubei province...In this study, the current status for breast diseases in a region with high-incidence of cervical cancer were epidemiologically investigated. From March to August, 2009, 17618 women, from Wufeng area of Hubei province, China, were recruited to screen breast diseases by using breast infrared diagnostic apparatus. Other diagnostic methods, such as B-mode ultrasound, X-ray mam-mography, needle biopsy and pathological examination were, if necessary, used to further confirm the diagnosis. The screening showed that 5990 of 17618 cases (34.00%) had breast diseases, 5843 (33.16%) had mammary gland hyperplasia, 48 (0.27%) had breast fibroadenoma, 11 (0.06%) had breast carcinoma, and 88 (0.50%) had other breast diseases. The peak morbidity of breast cancer was found in the women aged 50-60 ages. The morbidity of breast cancer was significantly increased in women elder than or equal to 50 years old (n=8, 0.157%) in comparison with that in the subjects younger than 50 years old (n=3, 0.024%) (u=2.327, P<0.05). It was shown that the occurrence of breast diseases was concentrated in women aged 20-40 years, while the total morbidity reached its peak at the age of 30 years and then decreased sharply after age of 40. Compared with the patients elder than or equal to 40 years old (n=3289, 27.46%), the morbidity rate of breast diseases was sig-nificantly increased in women less than 40 years old (2648 cases, 47.18%; P<0.001). However, there was no significant difference in the morbidity of breast diseases between the age group of 20-29 years and that of 30-39 years (P=0.453), and both of them were high. There was no significant asso-ciation between the morbidity of breast diseases and cervical cancer. Since the morbidity of breast diseases was higher among young women, more attention should be paid to the screening of breast diseases among young women for early diagnosis.展开更多
Fluoride mediated nano-sized ZSM-5(ZSM-5-F) with a high Si/Al ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene(MTP) reaction. High propylene selectivit...Fluoride mediated nano-sized ZSM-5(ZSM-5-F) with a high Si/Al ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene(MTP) reaction. High propylene selectivity(45%) was similar to ZSM-5-OH synthesized via a hydroxide route. However, ZSM-5-F showed much longer lifetime(305 h) compared with ZSM-5-OH(157 h) in spite of similar crystal size and aluminum content. Characterization by NH_3-TPD, Py-IR, OH-IR, SEM, TG-DTA, XRD and ~1H MAS NMR techniques indicated that the enhanced catalytic performance of ZSM-5-F is attributed to the fewer structural defects in the form of internal silanol groups and silanol nests.展开更多
Probabilistic safety assessment(PSA) is important in nuclear safety review and analysis. Because the design and physics of the fluoride salt-cooled high temperature reactor(FHR) differ greatly from the pressurized wat...Probabilistic safety assessment(PSA) is important in nuclear safety review and analysis. Because the design and physics of the fluoride salt-cooled high temperature reactor(FHR) differ greatly from the pressurized water reactor(PWR), the methods and steps of PSA in FHR should be studied. The high-temperature gascooled reactor(HTR-PM) and sodium-cooled fast reactors have built the PSA framework, and the framework to finish the PSA analysis. The FHR is compared with the PWR, HTR-PM and sodium-cooled fast reactors from the physics, design and safety. The PSA framework of FHR is discussed. In the FHR, the fuel and coolant combination provides large thermal margins to fuel damage(hundreds of degrees centigrade). The tristructuralisotropic(TRISO) as the fuel is independent in FHR core and its failure is limited for the core. The core damage in Level 1 PSA is of lower frequency. Levels 1 and 2 PSA are combined in the FHR PSA analysis. The initiating events analysis is the beginning, and the source term analysis and the release types are the target. Finally, Level3 PSA is done.展开更多
Objective: To discuss the epidemic strength of cardia and distant stomach cancers in the high risk region of esophageal cancer along the south Taihang mountain such as in Shexian, Linxian, and Cixian Counties, and to ...Objective: To discuss the epidemic strength of cardia and distant stomach cancers in the high risk region of esophageal cancer along the south Taihang mountain such as in Shexian, Linxian, and Cixian Counties, and to clarify the tasks for the control of upper gastrointestinal tract cancer as a whole in the region. Methods: Comparisons of incidence and mortality rates of esophageal, cardia and stomach cancers were made between Cixian, Linxian and Shexian Counties with reference to detection rates of cancer in situ and precancerous lesions of the three upper gastrointestinal cancers by endoscopic screening. The screening was performed from 1999 through 2004 in the three adjacent counties including a total of 6233 local residents aged 40 to 69 years old. Results: The incidence rates for cardia cancer for the male and female from 2000 through 2004 were 69.9 and 41.5, and the mortality rates were 54.3 and 33.2 respectively in Shexian County. Esophageal, cardia, and stomach cancers constitute about 70～80 percent of all malignant disease by incidence or mortality rates. Endoscopic survey with iodine staining can effectively detect squamous cell precancerous lesions in the esophagus, but the method is inadequate for the detection of adeno precancerous lesions of the cardia and stomach. Conclusion: The south Taihang mountain region is a high risk area not only for esophagus cancer, but also for cardia and stomach cancers. To control upper gastrointestinal tract cancers as a whole in the region, special attention should be paid to the control of cardia and stomach cancers. Presently, to find effective screening methods for detecting cardia and stomach precancerous lesions is especially important.展开更多
This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which ca...This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements.Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means(-6980 to -3651 pcm) and negative temperature coefficient(-6.32 to -3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient,have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including ~6Li depletion and tritium production.展开更多
In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region...In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.展开更多
NCEP/NCAR data are utilized to analyze an extreme flood year(1998) and an extreme dry year(2006) in the Sichuan-Chongqing region(SCR) and the results are as follows. The positive divergence of South Asia High(SAH) is ...NCEP/NCAR data are utilized to analyze an extreme flood year(1998) and an extreme dry year(2006) in the Sichuan-Chongqing region(SCR) and the results are as follows. The positive divergence of South Asia High(SAH) is stronger in the flood year; the position of the ridge line of SAH is southward compared with the annual average; Western Pacific Subtropical High(WPSH) extends westward and its ridge line is southward. In the drought year, the positive divergence of SAH is weaker, its ridge line is northward, and the position of WPSH is also northward. As shown in the dynamics, in drought(flood) years, negative(positive) vorticity advection in the upper atmosphere can cause the atmosphere to ascend(descend), and anomalous circulation of SAH displays divergence(convergence), and anomalous circulation of the lower atmosphere shows convergence(divergence). Thermal structure of the atmosphere shows that there is warm(cold) temperature advection in the lower atmosphere, and the vertical distribution of diabetic heating causes SAH's local circulation to display convergence(divergence) and affects vertical motion of the lower atmosphere circulation eventually. To some extent, the two extreme years in the SCR is closely related to the vertical motion of atmosphere circulation and the variation of such vertical motion is caused by differences of interactions between SAH and lower atmosphere circulations.展开更多
Magnetic reconnection is the most fundamental energy-transfer mechanism in the universe that converts magnetic energy into heat and kinetic energy of charged particles.For reconnection to occur,the frozen-in condition...Magnetic reconnection is the most fundamental energy-transfer mechanism in the universe that converts magnetic energy into heat and kinetic energy of charged particles.For reconnection to occur,the frozen-in condition must break down in a localized region,commonly called the ‘diffusion region'.In Earth's magnetosphere,ion diffusion regions have already been observed,while electron diffusion regions have not been detected due to their small scales(of the order of a few km)(Paschmann,2008).In this paper we report,for the first time,in situ observations of an active electron diffusion region by the four Cluster spacecraft at the Earth's highlatitude magnetopause.The electron diffusion region is characterized by nongyrotropic electron distribution,strong field-aligned currents carried by electrons and bi-directional super-Alfvénic electron jets.Also observed were multiple micro-scale flux ropes,with a scale size of about 5 c/ω_(pe)(12 km,with c/ωpe the electron inertial length),that are crucial for electron acceleration in the guide-field reconnection process(Drake et al.,2006 a).The data demonstrate the existence of the electron diffusion region in collisionless guide-field reconnection at the magnetopause.展开更多
National high-tech industrial development zones represent a major strategy of the Chinese government in developing high-tech industries and spurring regional economic growth. The effect of this policy is yet to be pro...National high-tech industrial development zones represent a major strategy of the Chinese government in developing high-tech industries and spurring regional economic growth. The effect of this policy is yet to be proven. Based on the panel data of 283 Chinese cities between 1984 and 2012, this paper investigates the effect of high-tech zones on regional economic development. Empirical results suggest that first, national hightech zones have remarkably enhanced regional GDP and per capita GDP growth, and this conclusion still holds true after multiple rounds of robustness test; second, the economic effect of national high-tech zones is subject to diminishing marginal return and compared with higher-tier cities, lower-tier cities benefited more from the creation of national hightech zones. This paper concludes that national high-tech zones where special policies are experimented and offered not only drive economic development but, if properly distributed across regions, may help reduce regional economic disparities as well. The results of this study provide important implications for the future distribution of national high-tech zones and the creation of other relevant policies.展开更多
The computer simulation of Al three-dimensional crystallite containing grain boundary of special type was carried out and its behaviour under high rate loading was investigated. The molecular dynamics method was used ...The computer simulation of Al three-dimensional crystallite containing grain boundary of special type was carried out and its behaviour under high rate loading was investigated. The molecular dynamics method was used and interaction betwen atoms was described based on pseudopotential method. Vortical character of the atom movements in the grain boundary region is realized under shear loading in certain directions. Back and forth movements of atoms in the direction which is perpendicular to the shear also arise. Amplitude of such movements is approximately equal to an interplanar distance in this direction.展开更多
Highly active anhydrous potassium fluoride has many uses. Its good performance is demonstrated in high activity, high recovery, low consumption and the low emission of accessory substances during the process of organi...Highly active anhydrous potassium fluoride has many uses. Its good performance is demonstrated in high activity, high recovery, low consumption and the low emission of accessory substances during the process of organic fluorination. Moreover. there is no need to use an expensive intertransferable catalyst in the process of fluorination. Under the same conditions and within the same time limit, the fluorination rate of the product is 97% while that of ordinary anhydrous potassium fluoride is 58%. The product, developed recently by the Shenyang Chemical Research Institute, can remain in a state of superfine powder for a long time in air展开更多
基金supported by CGS grants(Item Number: 121201053303, 1212010881305, 1212011120811 and 1212011402450)
文摘1 Introduction Massive tungsten-tin,rare and rare earth metals ore deposits were formed with the widespread granite magmatic activity in early Yanshanian period in the eastern Nanling region.Recent studies indicate that the Yanshanian highly differentiated-granite formation is closely related to the deposits of tungsten and tin,rare and rare earth metals mineralization in the
基金the financial support received from the China Scholarship Council(CSC)MERAGEM graduate school and the Ministry of Science,Research and Arts of the State of Baden-Wu rttemberg for funding research+4 种基金the support of the German Research Foundation(DFG)project(SE 1407/4-2)the support of the En ABLES,a project funded by the European Union’s Horizon 2020 research and innovation program under grant agreement(730957)the support of Epi Store project under grant agreement(101017709)the Centre for Electrochemical Energy Storage Ulm-Karlsruhe(CELEST)the support from the Karlsruhe Nano Micro Facility(KNMF)。
文摘With the recent development of high entropy materials, an alternative approach to develop advanced functional materials with distinctive properties that show improved values compared to conventional materials has been provided. The high entropy concept was later successfully transferred to metal fluorides and high entropy fluorides(HEFs) were successfully synthesized. Owing to their high theoretical specific capacities in energy storage applications, HEFs were utilized as cathode materials for lithiumion batteries(LIBs) and their underlying storage mechanisms were investigated. Instead of a step-bystep reduction of each individual metal cation, the HEFs seem to exhibit a single-step reduction process,indicating a solid solution compound instead of merely a mixture of different metal fluorides. It was also observed that the electrochemical behavior of the HEFs depends on each individual incorporated element. Therefore, by altering the elemental composition, new materials that exhibit improved electrochemical properties can be designed. Remarkably, HEFs with seven incorporated metal elements exhibited a better cycling stability as well as a lower hysteresis compared to binary metal fluorides.These findings offer new guidelines for material design and tailoring towards high performance LIBs.
基金Under the auspices of National Natural Science Foundation of China(No.31460117,41877024)。
文摘Soil aggregate stability,as an important indicator of soil functions,may be affected by seasonal freezing and thawing(SFT)and land use in high cold and wet regions.Therefore,comprehensive understanding the effects of SFT on aggregate stability in orchards during winter and spring is crucial to develop appropriate management strategies that can effectively alleviate the degradation of soil quality to ensure sustainable development of orchard ecosystems.To determine the mechanism of degradation in orchard soil quality,the effects of SFT on the stability of water-stable aggregates were examined in apple-pear orchards(Pyrus ussuriensis var.ovoidea)of four different ages(11,25,40,and 63 yr)on 0 to 5%slopes before freezing and after thawing from October 2015 to June 2016 in Longjing City,Yanbian Prefecture,Northeast China,involving a comparison of planted versus adjacent uncultivated lands(control).Soil samples were collected to investigate water-stable aggregate stability in three incremental soil layers(0–20,20–40 and 40–60 cm).In the same samples,iron oxide,organic matter,and clay contents of the soil were also determined.Results showed that the destructive influences of SFT on water-stable aggregates were more pronounced with the increased orchards ages,and SFT exerted severe effects on water-stable aggregates of older orchards(40 and 63 yr)than juvenile orchards.Undergoing SFT,the soil instability index and the percentage of aggregate destruction increased by mean 0.15 mm and 1.86%,the degree of aggregation decreased by mean 1.32%,and the erosion resistance weakened,which consequently led to aggregate stability decreased.In addition,soil free,amorphous,and crystalline iron oxide as well as soil organic matter and clay contents are all important factors affecting the stability of water-stable aggregates,and their changes in their contents were consistent with those in the stability of water-stable aggregates.The results of this study suggest that long-term planting fruit trees can exacerbate the damaging effects of SFT on aggregate stability and further soil erosion increases and nutrient losses in an orchard,which hider sustainable use of soil and the productivity orchards.
文摘The aim of this study was to investigate the effects of high dietary fluoride (F) on serum biochemistry and oxidative damage in broiler chickens. 280 one-day-old healthy avian broiler chickens were randomly allotted into four equal groups and fed with a corn-soybean basal diet containing 22.6 mg·F/kg (control group) or same basal diets supplemented with 400, 800, and 1200 mg·F/kg (high F groups I, II, and III) in the form of sodium fluoride for 42 days. At 42 days of age, the serum F content was markedly higher in the three high F groups than that in the control group. From 28 to 42 days of age, the contents of serum total protein (TP) and albumin (ALB) were significantly lower in the three high F groups. From 14 to 42 days of age, the activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT) and the creatinine (Crea) contents in the serum showed a marked increase in the three high F groups;aspartate aminotransferase (AST) activity and uric acid (Ua) content were significantly increased, and a significant increase in the content of malondialdehyde (MDA) along with marked decreases in the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), catalase (CAT), the glutathione (GSH) content and the ability to inhibit hydroxyl radical were observed in the high F groups II and III. In conclusion, F has accumulated in the blood circulatory system and dietary F in the range of 800 - 1200 mg/kg could significantly induce abnormalities of bone, liver and kidney, inhibit the synthesis of protein, enhance lipid peroxidation and disturb the antioxidative system of broiler chickens.
基金sponsored by the National Natural Science Foundation of China (30170681)the Foundation of Henan Institute of Science and Technology, China(6007)
文摘Thirty-two Wistar rats were divided randomly into four groups of eight with six females and two males in each group. The rats were exposed to high fluoride drinking water (45 mg F- L-1 from 100 mg NaF L-1), low dietary iodine (0.0855 mg kg-1), or both together in order to assess the effects of these three regimens on the thyroid function of the offspring rats. After the animal model was established, the offspring rats were bred and 10-, 20-, 30-, 60-, and 90-d-old rats were used for the experiment. The treatments for the offspring rats were the same as those of their parents. In comparison with control rats, the relative thyroid glands were changed by three regimens, but the mean values of thyroid weight in the experimental groups saw no marked difference. Serum TT3 levels were increased in all stages in the low iodine (LI) group. In the high fluoride (HiF) group, increase in TT3 levels was observed except in 20-d-old rats. Decrease in TT3 at 20- and 90-d and increase in TT3 at 30- and 60-d were found in HiF+LI group. Serum TT4 levels first saw an increase, and then dropped in the LI and HiF+LI group. However, an increase in TT4 was found in the HiF group. The levels of TSH in serum rocketed at d 20, and then dropped in the next stages in experimental groups. The results suggested that thyroid disorder could be induced by high flroride in drinking water, low iodine diet, or both of them. Exposure time to fluoride or low iodine diet was one of the important factors that fluoride can induce the development of thyroid dyfunction.
基金Financial supports for this work, are provided by the National Natural Science Foundation of China （NSFC） ＆ Shenhua Group Corporation Limited key support project of the coal joint fund （U1361203） and NSFC under Grant No. 41501562. Thanks are also due to some participants for rendering assistant cooperation during studies.
基金supported by grants from the National Basic Research Program of China(973 Program,2011CB100104)the National High-Tech R&D Program of China(2011AA100101)+2 种基金the National Natural Science Foundation of China(31071416)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciencesthe National Key Technologies R&D Program of China during the 12th Five-Year Plan period(2013BAD01B02)
文摘Grain number per spike(GNPS) is a major factor in wheat yield breeding.A new wheat germplasm Pubing 3504 shows superior features in spike traits.To elucidate the genetic basis of spike and yield related traits in Pubing 3504,282 F2:3 families were generated from the cross Pubing 3504×Jing 4839,and seven spike and yield related traits,including GNPS,spike length(SL),kernel number per spikelet(KPS),spikelet number per spike(SNS),thousand-grain weight(TGW),spike number per plant(SNP),and plant height(HT) were investigated.Correlation analysis indicated significant positive correlations between GNPS and spike-related traits,including KPS,SNS,and SL,especially KPS.A genetic map was constructed using 190 polymorphic simple sequence repeat(SSR),expressed sequence tag(EST)-SSR,and sequencetagged-site(STS) markers.For the seven traits measured,a total of 37 quantitative trait loci(QTLs) in a single-environment analysis and 25 QTLs in a joint-environment analysis were detected.Additive effects of 70.3%(in a single environment) and 57.6%(in a joint environment) of the QTLs were positively contributed by Pubing 3504 alleles.Five important genomic regions on chromosomes 1 A,4 A,4 B,2 D,and 4 D could be stably detected in different environments.Among these regions,the marker interval Xmag834–Xbarc83 on the short arm of chromosome 1 A was a novel important genomic region that included QTLs controlling GNPS,KPS,SNS,TGW,and SNP with stable environmental repeatability.This genomic region can improve the spike trait and may play a key role in improving wheat yield in the future.We deduced that this genomic region was vital to the high GNPS of Pubing 3504.
基金supported by grants from the foundation of Key Basic Research and Development Program of China(Program973)(No.2009CB521808)National Major Science and Technology Project(Key New Drug Creation and Development Program)(No.2009ZX09103-739)National Natural Science Foundation of China(No.30973472,81001151,81071663,30973205,30973184,81101964)
文摘In this study, the current status for breast diseases in a region with high-incidence of cervical cancer were epidemiologically investigated. From March to August, 2009, 17618 women, from Wufeng area of Hubei province, China, were recruited to screen breast diseases by using breast infrared diagnostic apparatus. Other diagnostic methods, such as B-mode ultrasound, X-ray mam-mography, needle biopsy and pathological examination were, if necessary, used to further confirm the diagnosis. The screening showed that 5990 of 17618 cases (34.00%) had breast diseases, 5843 (33.16%) had mammary gland hyperplasia, 48 (0.27%) had breast fibroadenoma, 11 (0.06%) had breast carcinoma, and 88 (0.50%) had other breast diseases. The peak morbidity of breast cancer was found in the women aged 50-60 ages. The morbidity of breast cancer was significantly increased in women elder than or equal to 50 years old (n=8, 0.157%) in comparison with that in the subjects younger than 50 years old (n=3, 0.024%) (u=2.327, P<0.05). It was shown that the occurrence of breast diseases was concentrated in women aged 20-40 years, while the total morbidity reached its peak at the age of 30 years and then decreased sharply after age of 40. Compared with the patients elder than or equal to 40 years old (n=3289, 27.46%), the morbidity rate of breast diseases was sig-nificantly increased in women less than 40 years old (2648 cases, 47.18%; P<0.001). However, there was no significant difference in the morbidity of breast diseases between the age group of 20-29 years and that of 30-39 years (P=0.453), and both of them were high. There was no significant asso-ciation between the morbidity of breast diseases and cervical cancer. Since the morbidity of breast diseases was higher among young women, more attention should be paid to the screening of breast diseases among young women for early diagnosis.
文摘Fluoride mediated nano-sized ZSM-5(ZSM-5-F) with a high Si/Al ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene(MTP) reaction. High propylene selectivity(45%) was similar to ZSM-5-OH synthesized via a hydroxide route. However, ZSM-5-F showed much longer lifetime(305 h) compared with ZSM-5-OH(157 h) in spite of similar crystal size and aluminum content. Characterization by NH_3-TPD, Py-IR, OH-IR, SEM, TG-DTA, XRD and ~1H MAS NMR techniques indicated that the enhanced catalytic performance of ZSM-5-F is attributed to the fewer structural defects in the form of internal silanol groups and silanol nests.
基金Supported by Chinese Academy of Science Strategy Precursor Science and Technology Project(No.XDA0205050)
文摘Probabilistic safety assessment(PSA) is important in nuclear safety review and analysis. Because the design and physics of the fluoride salt-cooled high temperature reactor(FHR) differ greatly from the pressurized water reactor(PWR), the methods and steps of PSA in FHR should be studied. The high-temperature gascooled reactor(HTR-PM) and sodium-cooled fast reactors have built the PSA framework, and the framework to finish the PSA analysis. The FHR is compared with the PWR, HTR-PM and sodium-cooled fast reactors from the physics, design and safety. The PSA framework of FHR is discussed. In the FHR, the fuel and coolant combination provides large thermal margins to fuel damage(hundreds of degrees centigrade). The tristructuralisotropic(TRISO) as the fuel is independent in FHR core and its failure is limited for the core. The core damage in Level 1 PSA is of lower frequency. Levels 1 and 2 PSA are combined in the FHR PSA analysis. The initiating events analysis is the beginning, and the source term analysis and the release types are the target. Finally, Level3 PSA is done.
基金This work was supported by the grants from The Natural Scientific Foundation of Hebei Province (No. C 2005000797 Hebei Significant Topic of Tackle Key Programs (No. 03276198D) Hebei Technology Program Item (No. 032761100D-1)
文摘Objective: To discuss the epidemic strength of cardia and distant stomach cancers in the high risk region of esophageal cancer along the south Taihang mountain such as in Shexian, Linxian, and Cixian Counties, and to clarify the tasks for the control of upper gastrointestinal tract cancer as a whole in the region. Methods: Comparisons of incidence and mortality rates of esophageal, cardia and stomach cancers were made between Cixian, Linxian and Shexian Counties with reference to detection rates of cancer in situ and precancerous lesions of the three upper gastrointestinal cancers by endoscopic screening. The screening was performed from 1999 through 2004 in the three adjacent counties including a total of 6233 local residents aged 40 to 69 years old. Results: The incidence rates for cardia cancer for the male and female from 2000 through 2004 were 69.9 and 41.5, and the mortality rates were 54.3 and 33.2 respectively in Shexian County. Esophageal, cardia, and stomach cancers constitute about 70～80 percent of all malignant disease by incidence or mortality rates. Endoscopic survey with iodine staining can effectively detect squamous cell precancerous lesions in the esophagus, but the method is inadequate for the detection of adeno precancerous lesions of the cardia and stomach. Conclusion: The south Taihang mountain region is a high risk area not only for esophagus cancer, but also for cardia and stomach cancers. To control upper gastrointestinal tract cancers as a whole in the region, special attention should be paid to the control of cardia and stomach cancers. Presently, to find effective screening methods for detecting cardia and stomach precancerous lesions is especially important.
基金supported by the Chinese Academy of Sciences TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)Thorium uranium fuel cycle characteristics and key problem research Project(No.QYZDY-SSW-JSC016)
文摘This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements.Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means(-6980 to -3651 pcm) and negative temperature coefficient(-6.32 to -3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient,have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including ~6Li depletion and tritium production.
基金supported by the National Natural Science Foundation of China(Nos. 41106018, 40975038)Program 973 (Nos. 2012CB417402, 2010CB950402, 2012CB955604)
文摘In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.
基金National Key Basic Research Development Program Project of China(2012CB417202)Key Project of National Natural Science Foundation(91337215)National Natural Science Foundation of China(41275051)
文摘NCEP/NCAR data are utilized to analyze an extreme flood year(1998) and an extreme dry year(2006) in the Sichuan-Chongqing region(SCR) and the results are as follows. The positive divergence of South Asia High(SAH) is stronger in the flood year; the position of the ridge line of SAH is southward compared with the annual average; Western Pacific Subtropical High(WPSH) extends westward and its ridge line is southward. In the drought year, the positive divergence of SAH is weaker, its ridge line is northward, and the position of WPSH is also northward. As shown in the dynamics, in drought(flood) years, negative(positive) vorticity advection in the upper atmosphere can cause the atmosphere to ascend(descend), and anomalous circulation of SAH displays divergence(convergence), and anomalous circulation of the lower atmosphere shows convergence(divergence). Thermal structure of the atmosphere shows that there is warm(cold) temperature advection in the lower atmosphere, and the vertical distribution of diabetic heating causes SAH's local circulation to display convergence(divergence) and affects vertical motion of the lower atmosphere circulation eventually. To some extent, the two extreme years in the SCR is closely related to the vertical motion of atmosphere circulation and the variation of such vertical motion is caused by differences of interactions between SAH and lower atmosphere circulations.
基金supported by National Natural Science Foundation of China(41421003 and 41627805)
文摘Magnetic reconnection is the most fundamental energy-transfer mechanism in the universe that converts magnetic energy into heat and kinetic energy of charged particles.For reconnection to occur,the frozen-in condition must break down in a localized region,commonly called the ‘diffusion region'.In Earth's magnetosphere,ion diffusion regions have already been observed,while electron diffusion regions have not been detected due to their small scales(of the order of a few km)(Paschmann,2008).In this paper we report,for the first time,in situ observations of an active electron diffusion region by the four Cluster spacecraft at the Earth's highlatitude magnetopause.The electron diffusion region is characterized by nongyrotropic electron distribution,strong field-aligned currents carried by electrons and bi-directional super-Alfvénic electron jets.Also observed were multiple micro-scale flux ropes,with a scale size of about 5 c/ω_(pe)(12 km,with c/ωpe the electron inertial length),that are crucial for electron acceleration in the guide-field reconnection process(Drake et al.,2006 a).The data demonstrate the existence of the electron diffusion region in collisionless guide-field reconnection at the magnetopause.
基金sponsored by the National Natural Science Foundation Program(Approval No.71303185)the Social Sciences Planning Foundation Program of the Ministry of Education(Approval No.13XJA790003)+2 种基金the Social Sciences Foundation Program of Shaanxi Province(Approval No.12D124)the Program of Shaanxi Provincial Department of Education(Approval No.12JK0152)the Support Program for Outstanding Young Teachers of Northwest University(Approval No.PR12152)
文摘National high-tech industrial development zones represent a major strategy of the Chinese government in developing high-tech industries and spurring regional economic growth. The effect of this policy is yet to be proven. Based on the panel data of 283 Chinese cities between 1984 and 2012, this paper investigates the effect of high-tech zones on regional economic development. Empirical results suggest that first, national hightech zones have remarkably enhanced regional GDP and per capita GDP growth, and this conclusion still holds true after multiple rounds of robustness test; second, the economic effect of national high-tech zones is subject to diminishing marginal return and compared with higher-tier cities, lower-tier cities benefited more from the creation of national hightech zones. This paper concludes that national high-tech zones where special policies are experimented and offered not only drive economic development but, if properly distributed across regions, may help reduce regional economic disparities as well. The results of this study provide important implications for the future distribution of national high-tech zones and the creation of other relevant policies.
文摘The computer simulation of Al three-dimensional crystallite containing grain boundary of special type was carried out and its behaviour under high rate loading was investigated. The molecular dynamics method was used and interaction betwen atoms was described based on pseudopotential method. Vortical character of the atom movements in the grain boundary region is realized under shear loading in certain directions. Back and forth movements of atoms in the direction which is perpendicular to the shear also arise. Amplitude of such movements is approximately equal to an interplanar distance in this direction.
文摘Highly active anhydrous potassium fluoride has many uses. Its good performance is demonstrated in high activity, high recovery, low consumption and the low emission of accessory substances during the process of organic fluorination. Moreover. there is no need to use an expensive intertransferable catalyst in the process of fluorination. Under the same conditions and within the same time limit, the fluorination rate of the product is 97% while that of ordinary anhydrous potassium fluoride is 58%. The product, developed recently by the Shenyang Chemical Research Institute, can remain in a state of superfine powder for a long time in air
