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Automatic milking systems (AMSs) for medium and large dairy farms in China require manual assistance to attach the teat cup, which greatly affects the milking efficiency and labor costs. In this regard, it is necessary to realize the automatic completion of cow teat attachment work. To address this issue, the authors developed a teat cup attachment robot for an AMS based on the theory of the solution of inventive problems (TRIZ). Specifically, we developed an enhanced algorithm for teat detection and designed a six-degree-of-freedom manipulator with integrated drive control. The design parameters were simulated and analyzed to validate their efficacy, while the rationality of the manipulator's movement during teat cup attachment was verified. The maximum displacement and angle error of the cup was 1.625 mm and 1.216 mm, respectively, as verified by the teat cup attachment error test. A dynamic response test showed that the manipulator could follow the teat of the cow in real time. The attachment time for teat cups was 21 s per cow, with a success rate of 98%. The performance of the teat cup attachment robot was capable of meeting the automatic attachment teat cup needs for medium and large dairy farms during milking. [ABSTRACT FROM AUTHOR]

A simple and sensitive method was developed for 239, 240Pu determination of sub-femtogram level in grass/vegetable sample using compact accelerator mass spectrometry (AMS). Pu was leached with HNO3-H2O2 after ashing, and purified with AGMP-1 M resin column from grass matrix. After target preparation using mixed titanium/iron oxides, the final sample was measured by 300 kV AMS. The average recovery was higher than 80% for large-size (> 20 g) grass sample in the entire procedure. 20 g environmental grass samples spiked with known amounts of 239Pu standard solution or certified reference materials were measured for method evalution, good agreement between the expected values and measured results has been achieved. The detection limits were estimated to be 1.5 × 10–16 g (0.34 µBq) for 239Pu and 9 × 10–17 g (0.8 µBq) for 240Pu, demonstrating the feasibility of AMS for the determination of the sub-femtogram level of 239,240Pu in environmental grass with global fallout signatures. Grass samples collected from China natural environment were successfully analyzed, and 239+240Pu concentration down to 1.6 × 10− 4 Bq/kg were measured in these samples. This improvement can stimulate environmental monitoring, ecological migration process and biological availability studies of Pu in the biosphere. [ABSTRACT FROM AUTHOR]

This study reports first results on uranium (236U), neptunium (237Np) and plutonium (239Pu and 240Pu) isotopes in shell samples (i.e. oyster, clam and scallop shells) from the coast of the South of China. The 240Pu/239Pu and 236U/238U atom ratios are used for source identification, and the 237Np/239Pu, 237Np/236U and 236U/239Pu non-isotopic atom ratios to study the relative bioaccumulation of Np, Pu and U during the shell formation. The obtained concentration levels are in the 104-106 atoms g−1 range in every case. Clear regional differences are observed in the case of the 240Pu/239Pu atom ratio, with average values lower along the coast of East China Sea (average 0.227 ± 0.120, n = 5) compared to the South China Sea (average 0.258 ± 0.018, n = 7), showing a possible influence of the Pu released at the Pacific Proving Ground nuclear test site. 236U/238U (× 10−8) atom ratios range from 0.046 ± 0.009 to 0.524 ± 0.135, in agreement with the expected levels in surface seawater from the China Sea. 237Np/239Pu (average 4.1 ± 2.6, n = 13) and 237Np/236U ratios (average 14 ± 10, n = 13) in the oyster shells are clearly enhanced compared to the estimated one in the surface seawater, pointing out higher bioaccumulation of Np compared to Pu and U. [Display omitted] • Radionuclides ( 236 U, 237 Np, and 239,240 Pu) in shells from the coast of the South of China have been studied for the first time. • The obtained concentration levels of 236U,237Np and 239+240Pu are in the 104-106 at g−1 range. • A higher bioavailability of 237Np compared to anthropogenic U and Pu isotopes in the seawater column is observed. • This study provided a multi-radionuclides ( 236 U, 237 Np, 238 U and 239,240 Pu) database on environmental samples in China. [ABSTRACT FROM AUTHOR]

The Guangxi Zhuang Autonomous Region in southern China is one of the most typical karst relief areas with various forms, and tiankeng is one of the most typical karst relief forms of the Quaternary Period. In this work, accurate measurements of tiankeng exposure ages were made. The exposure ages of carbonate rocks from the five largest tiankengs in the world, the DaShiwei, HuangJing, ChuanDong, DaTuo, and DaCao tiankengs, were determined by accelerator mass spectrometry to be at least 20–400 thousand years, which provides significant proof for activity of new tectonic movement of the Eurasian continent in the Quaternary. [ABSTRACT FROM AUTHOR]

Tiankeng, a typical Karst relief of the Late Quaternary Period, in the south of China, plays an important role when researching the surface shape and evolution of the Karst relief. The accumulation of Chlorine-36 (T 1/2 = 301 ka) through the interaction of cosmic ray particles with Ca, K and Cl in rocks allow it to be used as the ideal nuclide for determination of the exposure age and erosion rate of limestone. In this work, an improved 36Cl sample preparation method for Tiankeng limestone was presented. The Isotope Dilution-AMS technique allows for the simultaneous measurement of 36Cl and Cl with a single AMS sample preparation. The barium introduced during the sample preparation was removed to avoid ionizer poisoning and attain a higher and more stable beam current. The method is particularly suitable for limestone samples, as well as for soil, sediment and water samples. [ABSTRACT FROM AUTHOR]

Determining solid-phase gastric emptying (GE) in a human being is an important application in clinical practice as it can provide valuable information for the diagnosis of related digestive diseases. Currently, 99mTc gastric scintigraphy is considered as the gold standard for measuring GE. However, this method suffers from clinical drawback, such as radiation exposure. This study focuses on identifying alternative methods for GE measurement. Carbon-14 accelerator mass spectrometry (AMS) is a useful tool for biomedical projects due to its inherently high sensitivity and dynamic range, low dose and sample size requirements, and relatively short measurement time. However, it has not yet been implemented in GE tests. In this work, 14C AMS methodology was developed for breath samples. Measurements were conducted on a compact, single-stage AMS device at China Institute of Atomic Energy (CIAE). To investigate GE, micro-doses of 14C-octanoic acid, 13C-octanoic acid, and 99mTc were marked along with tracers in the same test meal and subsequently ingested by volunteers. The 14C-octanoic acid breath test (14C-OBT) in combination with AMS showed better counting statistics than those obtained for the 13C-OBT measured using infrared spectroscopy. The results also demonstrate a considerably lower radiation dose than that in 99mTc gastric scintigraphy. This work establishes an alternative method of 14C-AMS tracing to determine solid-phase GE in a human being, which could provide clinical technical support for a GE test and further expand the range of 14C-AMS applications in biomedicine. [ABSTRACT FROM AUTHOR]

• AMS fabric constraints on the magma flow of dykes in central NCC. • Typical opposed imbrication fabric found in two dykes. • The Fuping area is inferred to be or near a magma source position. Locating the magma source for the mafic dyke swarms in the North China Craton (NCC) is important for evaluating tectonic setting and emplacement mechanism. Here we have conducted systematic AMS studies on Paleoproterozoic dykes from the Fengzhen, Fuping and Lvliang areas of the NCC. Rock magnetic analyses indicate that PSD magnetite is the predominant magnetic carrier although the Lvliang dykes contain more SD magnetic grains than the Fengzhen and Fuping dykes. The Fengzhen and Fuping dykes have mostly normal AMS fabrics whilst the Lvliang dykes exhibit a larger proportion of intermediate AMS fabrics. Most of the Fuping dykes are found to have intruded sub-vertically upward although some fabrics indicate northward magma flow from imbrication and the distribution of K 1 AMS axes. The Lvliang dykes identify a southwestward magma flow from opposed imbrications and distributions of K 1 AMS axes. The Fuping area is thus interpreted to have been located near to the magma source which fed most dykes in the central NCC. A variety of magma sources are suggested for dykes in other parts of the NCC. Dykes near the southern margin of the craton probably resulted from lateral migration of magma from the Xiong'er source and contrast with the dykes in the central NCC fed by the Fuping magma source. Further Paleoproterozoic magma sources likely remain to be identified. [ABSTRACT FROM AUTHOR]

The Ocean University of China radiocarbon accelerator mass spectrometer center (OUC-CAMS) is equipped with a mini carbon dating system (MICADAS) from the Ionplus AG. The MICADAS allows measurements of both graphite and CO 2 samples because of the design of a hybrid ion source. Also, both 13C and 14C of organic samples can be measured at the same time because a stand-alone IRMS is coupled to the MICADAS. The OUC-CAMS provides routine 14C analyses on bulk organic carbon of various types, such as sediments, particulate matter, plant fragments, and compound-specific lipid biomarkers. Here we report the performance based on continuous analysis of international reference materials of 195 graphite data and 605 gas data carried out over the 2.5 years before 2022. [ABSTRACT FROM AUTHOR]

An Aerodyne quadrupole aerosol mass spectrometry (Q-AMS) was utilized to measure the size-resolved chemical composition of non-refractory submicron particles (NR-PM 1 ) from October 27 to December 3, 2014 at an urban site in Lanzhou, northwest China. The average NR-PM 1 mass concentration was 37.3 μg m −3 (ranging from 2.9 to 128.2 μg m −3 ) under an AMS collection efficiency of unity and was composed of organics (48.4%), sulfate (17.8%), nitrate (14.6%), ammonium (13.7%), and chloride (5.7%). Positive matrix factorization (PMF) with the multi-linear engine (ME-2) solver identified six organic aerosol (OA) factors, including hydrocarbon-like OA (HOA), coal combustion OA (CCOA), cooking-related OA (COA), biomass burning OA (BBOA) and two oxygenated OA (OOA1 and OOA2), which accounted for 8.5%, 20.2%, 18.6%, 12.4%, 17.8% and 22.5% of the total organics mass on average, respectively. Primary emissions were the major sources of fine particulate matter (PM) and played an important role in causing high chemically resolved PM pollution during wintertime in Lanzhou. Back trajectory analysis indicated that the long-range regional transport air mass from the westerly was the key factor that led to severe submicron aerosol pollution during wintertime in Lanzhou. [ABSTRACT FROM AUTHOR]

The annual incidence of new cancer patients in China is about 2 million, 30–40% of which will end up with bone metastasis. Profound study on the preclinical model and early diagnosis of cancer bone metastasis in rats are very significant for the drug development, better understanding and treatment of bone metastases. In order to monitor the process of bone metabolism and early detection of bone metastasis of cancer cells, a technique of 41 Ca isotope tracer combined with AMS has been developed and applied in the study on the bone metastasis of cancer cells by rat model. In this work, 3-month-old female Sprague–Dawley (SD) rats were randomly divided into different groups, and tumor cells injected respectively into the tail vein, femoral artery, femoral cavity and the thigh muscle to establish the rat models for bone metastases. The most appropriate model, i.e., the thigh muscle group, was finally adopted in our real metastases experiment. Each rat in this group was intramuscularly (i.m.) injected with 250 μl CaCl 2 solution (containing 1.4 mg Ca and 5nCi 41 Ca). About 40 days later, the rat mammary gland carcinoma cells (Walker 256) were injected into these rats following the established protocol. After bone metastasis, medicine interventions were performed. The sequential urine and blood samples were collected and analyzed for 41 Ca (by AMS) and N-terminal telopeptide (Ntx), respectively. Bone Mineral Density (BMD) values in the femur and the tibia were measured by CT scan. The results of 41 Ca/Ca in longitudinal urinary samples can sensitively reveal the skeletal perturbations caused by bone metastasis of rats, suggests that 41 Ca might be similarly developed for human use and improve clinical management through the assessment of the curative effect and non-invasive detection of the earliest stages of cancer growth in bone. [ABSTRACT FROM AUTHOR]

Magma flow directions for 6 Late Cretaceous mafic dyke swarms exposed in coastal southeastern China (SE China) were analyzed using anisotropy of magnetic susceptibility (AMS) and field evidence. Normal AMS fabrics are predominant. The AMS of the dyke swarms originates mainly from the distribution anisotropy of intersertal magnetite that crystallized during late stage magma flow or after the magma cooled. The AMS fabrics record tectonic stress combined with magma flow. Sub-vertical to vertical magma flow is inferred from symmetrical imbricated magnetic foliations of dyke walls and field evidence for 5 dyke swarms. The inferred (sub-) vertical flow directions also indicate that the magma chambers were probably just beneath the sampled locations. Low anisotropy degree, different orientations of principal AMS axes, and asymmetrical magnetic foliations of normal fabrics oblique to dyke walls indicate syntectonic emplacement of the Late Cretaceous dyke swarms under an extensional tectonic regime caused by Paleo-Pacific plate subduction. [ABSTRACT FROM AUTHOR]

High particulate matter (PM) pollution episodes still occur occasionally in urban China, despite of improvements in recent years. Investigating the influencing factors of high-PM episodes is beneficial in the formulation of effective control measures. We herein present the effects of weather condition, emission source, and chemical conversion on the occurrence of high-PM episodes in urban Shanghai using multiple online measurements. Three high-PM episodes, i.e., locally-accumulated, regionally-transported, and dust-affected ones, as well as a clean period were selected. Stagnant air with temperature inversion was found in both locally-accumulated and regionally-transported high-PM episodes, but differences in PM evolution were observed. In the more complicated dust-affected episode, the weather condition interacted with the emission/transport sources and chemical conversion, resulting in consecutive stages with different PM characteristics. Specifically, there were (1) stronger local accumulation in the pre-dust period, (2) dust-laden air with aged organic aerosol (OA) upon dust arrival, (3) pollutants being swept into the ocean, and (4) back to the city with aged OA. Our results suggest that (a) local emissions could be rapidly oxidized in some episodes but not all, (b) aged OA from long-range transport (aged in space) had a similar degree of oxygenation compared to the prolonged local oxidation (aged in time), and (c) OA aged over land and over the ocean were similar in chemical characteristics. The findings help better understand the causes and evolution of high-PM episodes, which are manifested by the interplays among meteorology, source, and chemistry, providing a scientific basis for control measures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this study, the ageing males' symptoms ( AMS) scale was translated into Chinese following methodological recommendations for linguistic and cultural adaptation. This study aimed to confirm the reliability, validation and applicability of the simplified Chinese version of the scale ( CN- AMS) in older Chinese men, a free health screening for men older than 40 years was conducted. All participants completed a health questionnaire, which consisted of personal health information, AMS scale, the generic quality of life (QoL) instrument SF36 and the Beck Depression Inventory ( BDI). The fasting blood samples of participants were collected on the day of completing the health questionnaire. Serum total testosterone ( TT), albumin and sex hormone-binding globulin levels were measured and the level of free testosterone was calculated (calculated free testosterone, CFT). A total of 244 men (mean age: 52 ± 7.3 years, range: 40-79 years) were involved in the investigation and provided informed consent before their participation. The reliability of CN- AMS was analysed as internal consistency reliability (Cronbach's alpha was 0.91) as well as a 4-week-interval test-retest stability (Pearson's correlation was 0.83) and found to be good. The validation of CN- AMS was analysed as the internal structure analysis (Pearson's correlation between total score and each item score r = 0.48-0.75), total-domain-correlation (among the three domains r = 0.47-0.68, p < 0.01; domains with the total score r = 0.81-0.88, p < 0.01), and cross-validation with other scales (with SF36 r = −0.59, p < 0.01; with BDI r = 0.50, p < 0.01). Androgen deficiency ( AD) was defined as the presence of three sexual symptoms (decreased frequency of morning erections, sexual thoughts and erectile dysfunction) in combination with TT < 11 nmol/L and CFT < 220 pmol/L, and the sensitivity and specificity for CN- AMS was 68.8 and 6.8% respectively. The CN- AMS had sufficient sensitivity in screening AD of older men, but the low specificity made it unsuitable to be adopted as the diagnostic criteria. The scanning capability of AMS scale for AD has the downward trend with ageing and a hypothesis is proposed to give a possible reason for the new finding. [ABSTRACT FROM AUTHOR]

Submicron aerosols (PM) in Beijing were studied using an Aerodyne aerosol mass spectrometer (AMS) from January to October 2008. This paper presents seasonal variations of different chemical components (sulfate, nitrate, ammonium, chloride and organics) and size distributions of PM. Results show that mass concentration of PM was highest in summer, and lowest in autumn. Organics represented the dominant species in all seasons, accounting for 36%-58% of PM, and their concentrations were highest in winter. Concentrations of inorganic components, sulfate, nitrate, and ammonium were highest in summer. Based on principal component analysis, organics were deconvolved and quantified as hydrocarbon-like and oxygenated organic aerosol (HOA and OOA, respectively). HOA was highest in winter, accounting for about 70% of organics. However, OOA was highest in summer, and had lower values in autumn and winter. A similar diurnal pattern of various components was observed, which is higher at nighttime and lower during daytime. HOA increased more dramatically than other species between 17:00 and 21:00 and peaked at noon, which could be related to cooking emissions. OOA, sulfate, nitrate, ammonium and chloride varied with the same trend. Their concentrations increased with solar radiation from 9:00 to 13:00, and declined with weakening solar radiation. Size distributions of all species showed apparent peaks in the range 500-600 nm. Size distributions of organics were much broader than other species, particularly in autumn and winter. Distributions of sulfate, nitrate and ammonium had similar patterns, broadening in winter. Contributions of different species were size-dependent; the finer the particle, the greater the contribution of organics. Organics represented more than 60% of particles smaller than 200 nm, contributing 50% to PM in winter. In spring and summer, HOA was the dominant organic fraction for particles smaller than 200 nm, while OOA contributed more to particles larger than 300 nm. In winter, HOA contributed more than OOA to all PM particles. [ABSTRACT FROM AUTHOR]

Abstract: A method has been developed for speciation analysis of ultra low level 129I in soil using sequential extraction combined with coprecipitation for separation of carrier free iodine and AMS measurement of 129I. Two loess profiles collected from northwest China were analyzed for species of 129I and 127I. Similar partitioning of 129I and 127I was observed in the loess profiles, the distribution of iodine isotopes followed an order of organic > leachable > reducible > residue. The 129I concentrations and 129I/127I ratios decreased exponentially with the depth, and 2 orders of magnitude lower in the deepest layer (60 and 90 cm) compared with the top layer, indicating a significant contribution of anthropogenic input in the upper layer, and high retention of 129I in soil. The mobility of 129I in different fractions decreased in an order of leachable > organic > oxides > residue. The results suggest that migration of iodine downwards in the soil profile is a slow process; the oxides and residue are the less mobile fractions of iodine. [Copyright &y& Elsevier]

Abstract: Two ancient tombs considered belonging to the Han Dynasty (206 BC to AD 220), were excavated in Hepu, Guangxi Zhuang Autonomous Region, China. According to the style of cultural relics, some excavated artifacts did not come from the region. If the age of the tombs can be confirmed as belonging to the Han Dynasty, the exotic artifacts present significant evidence to suggest that that Hepu is one of the oldest seaports on China’s ancient maritime trading route. Two wood samples were sent for 14C dating at CIRCE, Italy. The results of these measurements are presented and the related chronology is discussed. Considering the previous results from a pottery workshop and an excavated sea wharf, the interpretation of Hepu as one of the oldest seaports in ancient China and the important role it played is presented. [Copyright &y& Elsevier]

Abstract: In order to investigate the origin and age of a bowl-shaped crater with 1.8km diameter in northeastern China, a core drilling about 110m in total was carried out in 2009 at the center of the crater. A 106-m-thick unit of lacustrine sediment is revealed under a surface layer of about 1m of yellow soil. The impact origin has been confirmed based on geological analysis. In this paper, we report the AMS 14C dating results of lacustrine sediment. The data suggest that the meteorite impact in Xiuyan happened more than 50,000years ago and a two-section linear relationship of 14C ages with the depth shows a stable sediment environment through the two time stages. [Copyright &y& Elsevier]

Abstract: Paleoclimatic records from the Tibetan Plateau provide important clues for understanding the Asian monsoon and Asian climate systems. To reconstruct climatic and environmental changes in the southern Tibetan Plateau, a 3.77-m-long sediment core (PY608E–PC) was taken from the southeastern part of Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, we performed radiocarbon dating on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, we propose a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700cal BP. The linear sedimentation rate of the core was founded to be constant at 32.0cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene. [Copyright &y& Elsevier]

Abstract: The 14C level in annual plants is a sensitive tracer for monitoring fossil fuel derived CO2 in the atmosphere. Corn leave samples were selected from different regions of China, including high mountains in the Tibetan Plateau, grassland in Inner Mongolia, and inland and coastal cities during the summer of 2010. The 14C/12C ratio of the samples was measured with the NEC compact AMS system at the Institute of Heavy Ion Physics, Peking University. The fossil fuel derived CO2 was estimated by comparing the measured Δ14C values of corn leave samples to background atmospheric Δ14C level. The influences of topography, meteorological conditions and carbon cycling processes on the fossil fuel derived CO2 concentration are considered when interpreting the data. Our results show a clear association of the low Δ14C values with regions where human activities are intensive. [Copyright &y& Elsevier]

Abstract: Metamorphic Core Complexes (MCC) constitute remarkable features within wide rifts. Based on analogue and numerical modelling, MCC dynamics and structural development are mainly controlled by first geothermal gradient, second the compositional layering, and after the strain rate and partial melting. In the Late Mesozoic, continental extension occurred in East Asia leading to the development of MCC, magmatism and extensional sedimentary basins. Based on an integrated study (i.e. structural and finite strain analysis, petrofabrics, Anisotropy of Magnetic Susceptibility (AMS) and U/Pb on zircon dating), this paper aims at constraining the tectonic evolution and deformation mechanisms in the South Liaodong Peninsula (NE China). The Gudaoling massif is identified as a “migmatitic” MCC developed from Upper Jurassic (ca. 157–154Ma) to Early Cretaceous (ca. 128–113Ma). Intrusion of the Yinmawanshan synkinematic pluton (Early Cretaceous) to the south of the dome marks out the final stages of shearing along the Gudaoling detachment zone and of exhumation of the MCC into the upper crust. The Gudaoling MCC and the Yinmawanshan pluton stay in line with the coeval South Liaodong MCC, to the south, all making a ~140×30km wide extensional band formed during a regional E–W to NW–SE crustal stretching. The area shows a bi-phased development with a “slow” and a “fast” stage which corresponds to (1) crustal necking and (2) dome amplification/exhumation stages according to published thermo-mechanical modelling results. Finally, the Gudaoling MCC lower unit almost exclusively displays migmatites and anatectic granitoids of Late Jurassic and Early Cretaceous, respectively. Occurrence of partial melting during earlier stages of extension seems controlling the initiation of MCC (as a soft anomaly within the lower crust). In East Asia, a regional-scale thermal event, during Jurassic–Cretaceous times, may have significantly reduced the bulk lithosphere strength and locally induced partial melting, emphasizing pervasive deformations and development of a wide rift system. [Copyright &y& Elsevier]

Abstract: Carbonaceous aerosols comprising a large fraction of elemental carbon (EC) and organic carbon (OC) are considered to affect both global climate and human health. Radiocarbon measurements have been proved to be a useful isotopic tracer for distinguishing contemporary and fossil emissions. An optimized system of a two-step thermal preparation system for radiocarbon (14C) measurement of OC/TC is firstly established in China. In this system, OC/TC are converted into carbon dioxide under a pure oxygen flow at 340°C/650°C and then reduced to graphite for AMS target using the method of zinc reduction. Afterwards, radiocarbon measurements of the targets performed by the NEC Compact AMS System at the Institute of Heavy Ion Physics, Peking University. The measured results for estimated reference martial including HOx I, HOx II and IAEA-C6 are consistent with internationally accepted values. The radiocarbon-based source appointment of carbonaceous aerosols in China would be much more convenient and faster with the preparation system developed in this work. [ABSTRACT FROM AUTHOR]

Abstract: The Yangtze River is the largest single source of sediment to the continental shelf of the East China Sea. The quantity of material exported by the river is expected to decrease substantially as a consequence of an extensive continuing program of dam construction within the river catchment. We report here AMS measurements of plutonium isotope concentrations and ratios for selected depth increments from a sediment core, collected from the sub-aqueous delta of the Yangtze River estuary. The Pu derives from atmospheric nuclear weapons testing in the 1950s and 1960s, and is potentially a useful tracer of sediment deposition times in the marine environment. The results show considerable structure in the depth-concentration profile, and offer an excellent opportunity to compare Pu with the more commonly used 137Cs isotopic tracer. The AMS data show superior sensitivity and indicate that the 240Pu/239Pu ratio can provide a check on the deposition dates. The changes in the 240Pu and 239Pu concentrations and the 240Pu/239Pu ratios with sediment depth all indicate the possibility of using Pu as a geochronological tool for coastal sediment studies. [Copyright &y& Elsevier]

Abstract: The remains of an ancient wooden boat were unearthed at the Bibong-ri shell mound site. The site was located at Bibong-ri, Bugog-myeon, Changnyeong-gun, Gyeongsangnam-do in South Korea. A substantial fragment of the vessel was discovered in the lowest layer of the site. We collected 17 samples of charcoal and wood from pebble, sand, and shell layers. Sample preparation extracted the carbon from each sample material and converted it into graphite for AMS radiocarbon dating. Radiocarbon dates of the samples indicate that they belong to the Neolithic period and that the boat dates from ca. 5700 BC. To this point, the oldest known boat in the world has been a wooden boat dating from ca. 5500 BC in China. Other ancient boats from around the world include a logboat dating from ca. 3600 BC in Japan and a fleet of wooden boats dating from ca. 3000 BC in Egypt. The Bibong-ri boat is the first boat from the Neolithic period ever found in South Korea and must represent one of the world’s oldest known boats. [Copyright &y& Elsevier]

Abstract: Some long-lived nuclides, such as 36Cl, 41Ca, 53Mn, 79Se, etc., are very interested in life science, environment science, geo- and cosmo-sciences, nuclear wastes management, and other fields. Taking the advantages in high sensitivity and the strong ability to reduce the interferences from molecular ions and isobars, AMS has been one of the most promising methods for the measurement of these nuclides. However, the sensitivity of AMS is often unsatisfactory due to the interferences of stable isobars especially for medium and heavy radioisotopes. Gas-filled time of flight (GF-TOF), Gas-filled Magnet with a time of flight (GFM-TOF), Bragg Curve detector and energy loss (ΔE) combined with a Q3D magnetic spectrometer (ΔE-Q3D) are among the techniques used or being developed in AMS lab of China Institute of Atomic Energy, in an attempt to further reduce the interferences from isobars. These techniques will be tested in our AMS measurement of 53Mn, 79Se, 93Zr, 99Tc, etc., for identifying isobaric interferences. [Copyright &y& Elsevier]

Abstract: To study the Pu concentration and isotope ratio distributions present in China, the 239+240Pu total activities and 240Pu/239Pu atom ratios in core soil samples from Hubei Province in central China were investigated using Accelerator Mass Spectrometry (AMS). The activities ranged from 0.019 to 0.502mBqg−1 and the 239+240Pu inventories of 45 and ∼55Bqm−2 agree well with that expected from global fallout. The 240Pu/239Pu atom ratios in the soil ranged from 0.172 to 0.220. The ratios are similar to typical global fallout values. Hence, any close-in fallout contribution from the Chinese nuclear weapons tests, mainly conducted in the 1970s, must have either been negligible or had a similar 240Pu/239Pu ratio to that of global fallout. The top 10cm layer of the soil contributes ∼90% of the total inventory and the maximum concentrations appeared in the 2–4cm or 4–6cm layers. It is suggested that climatic conditions and organic content are the two main factors that affect the vertical migration of plutonium in soil. [Copyright &y& Elsevier]

A study of the anisotropy of magnetic susceptibility (AMS) has been done at 24 sites in the Tethyan Himalaya Thrust Belt in SE-Tibet. The sites are located in the Triassic slates. Generally Kmin axes are well grouped at the pole of the mesoscopic foliation. Magnetic foliation strikes WNW-ESE but shows different dips south and north of the Dalmar fault: it has intermediate dips toward the south in the northern part and intermediate dips to the north in the southern part of the same fault. We present new magnetic fabric data to better understand the tectonometamorphic history of SE-Tibet, a key area to understand the formation history of the Himalaya-Tibetan Plateau uplift. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Dongguashan quartz-diorite stock was built by multiple magma pulses. • Early magma pulse was guided by inherited NE-SW-trending structure in country rock. • Late magma pulse emplacement was assisted by regional extensional regime. • Eastward magma emplace might control location of skarnization in stock eastern sideable 1. We present a study on the Dongguashan quartz diorite stock which is the largest Early Cretaceous intrusion associated with skarn-porphyry polymetallic ore deposit in the Tongling Ore Cluster, Middle-Lower Yangtze Metallogenic Belt in East China. The Dongguashan quartz diorite show massive texture without obvious foliation, and intrusive contact was locally observed inside of the stock. The anisotropy of magnetic susceptibility (AMS) results of the stock show two distinct groups. The Group I (G-I) is dominated by NE-SW-striking magnetic foliation with variably oriented magnetic lineation. The Group II (G-II) that intruded into G-I is characterized by steep NW-SE-striking magnetic foliation and lineation, which are parallel to the vein-like orebody developed in the stock. The 3D geometrical modelling of the stock displays a triangular shape in plan-view with an eastward bulge and irregular stock boundary in the eastern side and the contact surface is steeper in the west than that in the east, denoting that the stock was constructed with an eastward magma accretion trend. Furthermore, the Dongguashan quartz diorite has a wide range of composition and geochronological data, suggesting a multiple magma pulses emplacement model. Accordingly, we propose that the Dongguashan stock was constructed by at least two stages magma pulses. The earlier stage magma pulses intruded along the NE-SW-striking pre-emplacement structures in the country rock and partly intruded into the lithological and mechanical discontinuous interfaces which yielded the stratabound skarn orebody. The eastward magma accretion produced a highly deformed and longer heated country rock on the eastern side of the stock, favoring the orebody development along the eastern stock-country rock contact interface. The late-stage magma pulse and the parallelism among the trend of magnetic foliation of G-II, extensional structure and vein-like orebody suggest that the vein-type orebodies may controlled by both magma emplacement and regional tectonics. [ABSTRACT FROM AUTHOR]

Abstract: A compact 14C AMS system manufactured by the National Electrostatics Corporation has been installed at the Institute of Heavy Ion Physics, Peking University. The system is based on a Model 1.5SDH-1 Pelletron accelerator with a maximum terminal voltage of 0.6MV. The 14C measurement accuracy with this system is better than 0.4% and the machine background is lower than 0.03pMC. The performance of the new system, especially the background and the δ13C measurements, is presented. Several important applications are also described briefly. [Copyright &y& Elsevier]

We compare new anisotropy of magnetic susceptibility (AMS) data with previously-determined paleoclimatically sensitive parameters for a loess profile at Lingtai, central Loess Plateau, China, to unravel factors that control loess AMS. Magnetic lineations are clustered along NE–SW and NW–SE orientations during cold and warm periods, respectively, which probably corresponded to paleowind directions of both winter and summer monsoons. Anomalously steep magnetic foliations coincidentally occur at the paleoclimatic stage boundaries, indicating sediment disturbance. Lineation strength appears to be sensitive to millennial-scale rapid paleoclimatic fluctuations. Generally, the winter monsoon produces a lower degree of lineation than the summer monsoon. Furthermore, by studying lineation subsets for the cold and warm periods, we find that the cold-interval lineation strengths co-vary with grain size over the last ∼70 ka. During the last interglacial (about 74–128 ka), the lineation and declination of the susceptibility maximum (Dec-Kmax) are sensitive to rapid fluctuations in winter and summer monsoons. Long-term trends of magnetic foliation and anisotropy degree replicate grain size variations, with superimposed short-term peaks related to post-depositional compaction, as suggested by density. The AMS shape parameter (T) indicates oblate fabrics. These new findings will not only improve our understandings of loess AMS, but also expand the possibilities of paleoclimatic studies in the Chinese loess. [Copyright &y& Elsevier]

Cooking organic aerosol (COA) is an important source of particulate pollutants in urbanized regions. Yet, the diversity and complexity of COA components make direct identification and quantification of COA difficult. In this study, we conducted collocated OA measurements with an aerosol mass spectrometer (AMS) and a thermal desorption aerosol gas chromatography-mass spectrometer (TAG) in Shanghai. Cooking molecular tracers (e.g., C18 fatty acids, azelaic acid) measured by TAG provide unambiguous source information for evaluating the tracer ion (C 6 H 10 O + , m / z 98) used for identification and apportionment of COA in AMS analysis. Based on the collocated AMS and TAG measurements, two COA factors, namely, a primary COA (PCOA) and an oxygenated COA (OCOA) produced from rapid oxygenation of freshly emitted PCOA, were identified. Criteria for identifying COA factors from AMS analysis with different oxygenation levels are proposed, i.e. , characteristic mass spectra, temporal variations, etc. Furthermore, two positive matrix factorization approaches, namely, AMS-PMF and the molecular marker (MM)-PMF, were compared for COA quantification, where high consistency was found with the contribution of COA to total PM 2.5 mass estimated to be 9 ± 7% by AMS-PMF and 6 ± 5% by the MM-PMF. Our study highlights the important impacts of cooking activities on air quality in urban areas. We also demonstrate the advantage of conducting collocated measurements using multiple high time resolution mass spectrometric techniques in advancing our understanding of atmospheric OA chemistry and improving the accuracy of source apportionment.

Abstract: Lake Pumoyum Co is on the southeastern Tibetan plateau (altitude, ∼5030m asl; lake surface area, 281km2; maximum water depth, 65m). We obtained 14C dates on total organic carbon (TOC) for three sediment cores from Lake Pumoyum Co, covering the period from the last glacial to the Holocene, and compared them with 14C ages on plant residue concentrates (PRC fraction, mainly terrestrial plant residues) and aquatic plant fragments in the cores. The calibrated ages of TOC were older than those of the PRC fraction in the sediment cores by ca. 0.6–11.3kyr. The calculated dead carbon fraction ( f dead carbon) values for TOC increased during 9.5–5.5calka BP, and fluctuations of f dead carbon paralleled variations in Asian monsoon intensity [Y. Wang et al., Nature 451 (2008) 1090]. One possible explanation for these results is that large amounts of terrestrial organic materials containing old carbon were supplied to the lake (“old carbon effects” from lake terrace, paleosol and/or stratum with dead 14C) when the lake level rose rapidly and its catchment area expanded during the Holocene climate optimum (9.5–5.5calka BP). [Copyright &y& Elsevier]

The Shibei pluton is a Late Jurassic granitic body in the South China Block (Fujian province), featured by macroscopically isotropic granite and undeformed margins, which are also characteristics for most of the Late Jurassic plutons in southeastern China. Our field observations, fabric investigations and gravity modelling allow us to decipher the internal structure, overall geometry, magma accumulation and emplacement processes of the Shibei pluton. Magnetic fabrics of the Shibei pluton can be divided into two distinct groups. The first one, observed in the southern-central part of the pluton, is characterized by high-angle to sub-vertical (54°-90°) NE-SW-striking magnetic foliations and variably plunging magnetic lineation. The second group, recognized in the northern part of the pluton, shows variably dipping (22°-88°) magnetic foliation, which generally strikes subparallel to pluton-country rock contacts, and irregularly oriented magnetic lineation. The Bouguer gravity modelling demonstrates that the pluton has a tabular geometry with a N-S-striking long axis, and a length-width-thickness ratio of ~32:8:1. The intrusion thickness gradually decreases from the southwest margin (ca. 2.5 km) to the northeast margin (ca. 0.5 km). Moreover, an undulating bottom with one or more convex intruding roots can be observed. Integrating published geochronological and regional tectonic data, we propose that the Shibei pluton was constructed by successive NE-SW-striking magma injections. Emplacement of early magma batches started in the SW part of the pluton by magma injection, which was guided by inherited structures produced by pre-emplacement tectonic events. Continuous magma injections were laterally accreted to earlier emplaced magma intrusions, and/or injected along lithological and/or structural discontinuities within the country rocks at upper crustal level without producing ductile deformation in the pluton-country rock contact zone. Our structural and fabric investigations indicate that the SE South China Block was not subjected to a major tectonic deformation during the Late Jurassic period. • Emplacement of the Shibei pluton was assisted /guided byinherited structures produced by pre-emplacement tectonic events. • The pluton was formed by several NE-SW-striking magma injections started in the SE part of the pluton and northward accretion. • The SE part of the South China Block is under a tectonic quiescence setting during late Jurassic epoch. [ABSTRACT FROM AUTHOR]