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Effects of frying cycles of two types of edible oil on dynamic viscosity were studied by ultrasonic shear‐wave reflectance method. Factors affecting the reflection coefficient were analyzed theoretically. The experimental methods and parameters are carefully analyzed and optimized in the low‐viscosity case. The viscosity of the reheated oil samples was characterized by the reflection amplitudes at (25 ± 0.2)°. Three methodologies for data post‐processing were used to calculate the reflection magnitudes. The results show that viscosity increases with repeat times of heating. The viscosity obtained by the integral ratio in a frequency band is closer to those obtained by rheometers than those from central frequency and multiple reflection. It indicates that the shear‐wave reflectometry can be extended further used to measure low‐viscosity liquids by appropriate signal processing. In addition, the heating times of a given procedure is highly correlated with the viscosity of edible oil (R2 >.93). We also attempted to evaluate the oil deterioration by predicting the amounts of carbonyl and fatty acids based on the relationship between viscosity and indicator content. Practical Applications: Viscosity is an important physical property and a quality index of edible oil. Not only viscosity changes, aging, and decay phenomena will even occur in the process of repeated heating of edible oils at high temperature. As a convenient and nondestructive method, the ultrasonic shear‐wave reflectance method can realize the rapid detection of the viscosity of reheated oils in situ. Therefore, this method has the potential to monitor frying oil quality online, which is expected to evaluate the degree of aging and deterioration of reheated edible oil. [ABSTRACT FROM AUTHOR]

The Gaoshan gold-silver deposit, located between the Yuyao-Lishui Fault and Jiangshan-Shaoxing fault in Longquan Area, occurs in the Suichang-Longquan gold-silver polymetallic metallogenic belt. This study conducted an investigation for ore-forming fluids using microthermometry, D-O isotope and trace element. The results show that two types of fluid inclusions involved into the formation of the deposit are pure liquid phase and gas-liquid phase aqueous inclusions. The homogenization temperature and salinity of major mineralization phase ranges from 156°C to 236°C (average 200°C) and 0.35% to 8.68% (NaCleqv) (average 3.68%), respectively, indicating that the ore-forming fluid is characteristic of low temperature and low salinity. The ore-forming pressure ranges between in 118.02 to 232.13′105 pa, and it is estabmiated that the ore-forming depth ranges from 0.39 to 0.77 km, indicating it is a hypabyssal deposit in genesis. The low rare earth elements content in pyrites, widely developed fluorite in late ore-forming stage and lack of chlorargyrite (AgCl), indicates that the ore-forming fluid is rich in F rather than CI. The ratios of Y/Ho, Zr/Hf and Nb/Ta of between different samples have little difference, indicating that the later hydrothermal activities had no effects on the former hydrothermal fluid. The chondrite-normalized REE patterns of pyrites from country rocks and ore veins are basically identical, with the characteristics of light REE enrichment and negative Eu anomalies, implying that the ore-forming fluid was oxidative and derived partly from the country rocks. The δD and δ18O of fluid inclusions in quartz formed during the main metallogenic stage range from -105‰ to -69 ‰ and -6.01‰ to -3.81‰, respectively. The D-O isotopie diagram shows that the metallogenic fluid is characterized by the mixing of formation water and meteoric water, without involvement of magmatic water. The geological and geochemical characteristics of the Gaoshan gold-silver deposit are similar to those of continental volcanic hydrothermal deposit, and could be assigned to the continental volcanic hydrothermal gold-silver deposit type. [ABSTRACT FROM AUTHOR]

Molybdenum is one of the dominant minerals in China because of its rich reserves. In recent years, outstanding breakthroughs have been made in molybdenum prospecting in China, and the distribution of molybdenum deposits in China is found to have a 'planar pattern'. In general, the molybdenum deposits are concentrated in eastern China, including the largest molybdenum reserves of Henan Province. In terms of the scale of molybdenum deposits, the identified resources of the superlarge deposits are the most important, which account for about 53% of the whole country, and those of the large deposits account for about 30%, those of the medium-sized deposits account for about 14%, those of the small-sized deposits, mine spots and mineralization account for about 3%. The molybdenum deposits are mainly classified as porphyry type, skarn type, hydrothermal (vein) type and sedimentary (metamorphic) type in genesis, and the identified resources of these types account for 85.75%, 8.83%, 2.79% and 2.63% of the total resources respectively. Based on the statistics of precise chronology data of molybdenites Re-Os, Mo-mineralization can be divided into 6 periods in Chinese geological history, which are Precambrian (>800 Ma), Cambrian-Silurian (540-415 Ma, Caledonian), Devonian-Permian (400-290 Ma, Hecynian), Triassic (260-200 Ma, Indosinian), Jurassic-Cretaceous (195-70 Ma, Yanshanian) and Paleogene-Neogene (65-10 Ma, Himalayan). Mo mineralization during the Yanshanian period is the strongest one, in which about 76.69% of the Chinese total identified resources was formed. The second is the Himalayan period. According to spatial-temporal distribution characteristics of molybdenum deposits, the metallogenic regularity of molybdenum deposits was preliminarily summarized, and 41 level-III molybdenum-forming belts, 13 level-II molybdenum-forming provinces and 4 level-I molybdenum-forming domains were ascertained in the mainland of China. There are 39 metallogenic series of and 60 sub-series of molybdenum deposits with molybdenum as the dominant metal and corresponding representative molybdenum deposits proposed. Metallogenic lineages of molybdenum deposits were also established. Spatial-temporal evolution of different types of molybdenum deposits, and the relationship between Mo-mineralization and tectonic evolution have been discussed in this paper. On this basis, the authors think that element Mo is an effective tracer for recording the crustal evolution history of China. At present, there are some problems in the exploration of Mo deposits in China, such as uneven exploration degrees in eastern and western China, shallow exploration depth, low and uneven grade, complex associated components, difficulty of mineral development and utilization, increasing costs of prospecting, and so on. According to successful experience of superficial and deep prospecting and considering also the discussion above, some suggestions are proposed for the prospecting of molybdenum deposits in the future. [ABSTRACT FROM AUTHOR]

China has widely distributed silver deposits, and is rich in silver resources. Although silver deposits are mainly associated with Pb-Zn deposits, a number of independent silver deposits have also been discovered in recent years. Silver deposits include different types, such as submarine volcanism and continental volcanism related type, intrusion related type, and sedimentary related type. This study summarized the metallogenic regularity of China's silver deposits systematically based mainly on the data from 490 silver deposits. It is shown that submarine volcanic sedimentary type, continental volcanic or sub-volcanic type, skarn type, hydrothermal type (including vein type and stratabound type), sedimentary metamorphic type, sedimentary type and regolith type should be regarded as the most important prediction types of silver deposit. A total of 32 silver mineralization belts and 111 silver concentration areas have been delineated. The map of 'Spatial distribution of silver mineralization belts in China' and other series of maps finished in this study may provide a theoretical basis for the evaluation and prognosis of silver resources potential in China. [ABSTRACT FROM AUTHOR]

China is rich in tin resources, and contains many types of tin deposits. Among the tin deposit types, the cassiterite-sulfide type, skarn type and quartz vein type occupy a large proportion of tin resources and reserves. From the aspect of exploitation and utilization, the most important types are cassiterite-sulfide type and quartz vein type. The cassiterite-sulfide type tin deposits are mainly located in Northern Guangxi and Eastern Yunnan, skarn type deposits are mainly distributed in the ore-concentration areas of South Hunan in Middle Nanling, and the quartz vein type tin deposits are mainly distributed in South China, such as Western Fujian, Middle Jiangxi, Northern Guangzhou and Southern Hunan. The most important metallogenic epoch for tin deposits is the Mesozoic era. The metallogenic geotectonic background is mainly continental environments after orogeny process, with strong tectonic changes, interlaced deep fracture and frequent magmatism. And the most distinctive feature is the well developed Mesozoic granites, which have a close relationship with tin mineralization. Based on the detailed study of the data from 873 tin deposits in China, this paper summarized the metallogenic regularity of tin deposits, classified 20 important metallogenic series of tin or tin-associated deposits, and inferred that the cassiterite-sulfide type, skarn type, quartz vein type and greisen type are the main prediction types of tin resources. Forty-four tin-mineralization belts were divided, among which, 19 belts are the most important. In addition, a series of maps about tin metallogenic belts and tin metallogenic regularity were compiled, aiming to provide theoretical basis for potential estimation and prediction of tin mineral resources. [ABSTRACT FROM AUTHOR]

Gold is one of the most important mineral resources in China with its rich mineral resources. In recent years, significant progress has been made on the process of gold resource exploration. Some large and giant gold deposits were newly found and some important expansions in the main mining regions were also been completed. Studies on metallogenic regularity of gold deposits in China also have made achievements with a long-term work. This review aims to conclude the achievements of research on gold metallogenic regularity in China. Based on the data of about 2000 gold deposits and other ore (mineralized) occurrences, gold deposits in China were classified into five prediction types: gold deposits genetically related to granite-greenstone formation, gold deposits related to sedimentary formation (including the Carlin type and the metamorphosed clastic rock related vein gold deposit), gold deposits genetically related to volcanic rocks (including the continental and marine types), gold deposits genetically related to intrusions (including the porphyry type and the inner intrusion and contact zone related gold deposit), gold deposits of supergenesis (including fracture zone-altered rock gold deposit, placer gold deposit, gossan type gold deposit and soil type gold deposit). Statistics on precise chronology data of gold deposits indicate that there occurred 5 main periods of gold-mineralization in geological history of China. They were Neoarchean to Paleoproterozoic, Meso-Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic. Gold deposits in China mainly formed in the Mesozoic and the Cenozoic. On the studies of the spatial-temporal distribution characteristics of gold deposits, 53 gold-forming belts were delineated in China. The metallogenic regularity of gold deposits was preliminarily summarized and 71 gold metallogenic series were proposed in China. This suggests that it is necceary to deepen the study on metallogenic regularity of gold deposits and to provide the theory guide for the ore-prospecting for gold resources in China. [ABSTRACT FROM AUTHOR]

1. The common carp ( Cyprinus carpio L.) is one of the most widely distributed and important freshwater fishes in the world. In China, the common carp has been recognised as three subspecies: C. carpio haematopterus, C. carpio rubrofuscus and C. carpio carpio. The Nanling Mountains have been suggested as providing the dividing line between C. carpio haematopterus and C. carpio rubrofuscus. However, the demographic history and gene flow of the common carp in China is not clear. 2. We collected mitochondrial COII and D-loop sequences (1494 bp) from 241 individuals distributed in eight major river drainages across China. The objective was to provide the first investigation into population genetic structure, demographic history and migration patterns of the common carp from these river drainages, and to assess the validity of the three subspecies. 3. Phylogenetic analysis did not result in three major monophyletic lineages corresponding to the three subspecies. The Nanling Mountains do not form a border separating C. carpio haematopterus and C. carpio rubrofuscus.amova showed low population differentiation, with 11.60% of the molecular variance found among river drainages. Pairwise FST values between river drainages were moderate (0.0331–0.2617). Substantial gene flow detected in coalescent analysis between drainages showed that the Yangtze drainage was the centre from which migrants moved northward, southward and north-westward. Human-mediated translocation has confounded our ability to identify subspecies of common carp in China. [ABSTRACT FROM AUTHOR]

The mitten crab, Eriocheir sensu stricto, is economically important in East Asia, although it is an invasive species in Europe and North America. Little is known about its population structure and historical demography in its native range, especially along the Pacific coast of China. We collected mitochondrial cytochrome oxidase subunit II and cytochrome  b sequences from 154 individuals distributed in the rivers along the Chinese coast and 15 individuals from Japan. Phylogenetic analysis resulted in three major monophyletic groups: northern China, southern China and Japan. Negligible migration was detected among those groups by coalescent analysis. Hence, we support the recognition of three species: Eriocheir hepuensis in southern China, Eriocheir sinensis in northern China and Eriocheir japonica in Japan. The populations in the middle (the Oujiang and Minjiang Rivers) possess a mixture of haplotypes similar to either the northern or the southern haplotypes. We believe that secondary intergradation as the most likely cause of the clinal variation based on examining the genetic variation in the latitudinal space. The estimated divergence time between E. sinensis and E. hepuensis is 2.24 million years ago (Ma), while the divergence time between E. japonica and E. sinensis is 1.83 Ma. Both are in the late Pliocene, suggesting that land bridges associated with low sea level during that time might have severed as vicariant barriers for speciation. The divergence of the northern population and the ‘northern haplotypes’ in the middle population was estimated at 0.12 Ma, while the time separating the southern population and the ‘southern haplotypes’ in the middle populations was estimated as 0.16 Ma, implicating possible secondary contact in the late Pleistocene. [ABSTRACT FROM AUTHOR]