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A natural calcite sample MNP is prepared as a potential reference material for in situ Sr isotope analysis.

The PAS-synthesized sphalerite has a homogeneous sulfur isotopic composition and is suitable to be a matrix-matched reference material for in situ S isotope measurements of sphalerite.

This study proposes a new synthesized protocol for cassiterite reference material for in situ Sn isotope measurement using fsLA-MC-ICP-MS.

Localization and navigation are the two most important tasks for mobile robots, which require an up-to-date and accurate map. However, to detect map changes from crowdsourced data is a challenging task, especially from billions of points collected by 3D acquisition devices. Collecting 3D data often requires expensive data acquisition equipment and there are limited data sources to evaluate point cloud change detection. To address these issues, in this Shape Retrieval Challenge (SHREC) track, we provide a city-scene dataset with real and synthesized data to detect 3D point cloud change. The dataset consists of 866 pairs of object changes from 78 city-scene 3D point clouds collected by LiDAR and 845 pairs of object changes from 100 city-scene 3D point clouds generated by a high-fidelity simulator. We compare three methods on this benchmark. Evaluation results show that data-driven methods are the current trend in 3D point cloud change detection. Besides, the siamesenetwork architectureis helpful to detect changes in our dataset. We hope this benchmark andcomparative evaluationresults will further enrich and boost the research of point cloud change detection and its applications.

Learning about the regional business model is essential for the sustainable development of the regional economy. From the perspective of urban renewable energy, city A is the product of energy development. This paper analyzes the current situation and existing problems of the industrial model of city A through fuzzy k-means clustering algorithm. The results show that although the optimization of industrial structure in city A has achieved some results, the more intuitive problems mainly include low labor productivity of the primary industry, strong resource dependence, insufficient extension of industrial chain, and slow development of technology intensive industries. This paper uses fuzzy k-means clustering algorithm to select the leading industries from the perspective of the current situation of leading industries, urban development pattern, and regional policies in city A. The results show that, as a renewable resource-based city, the leading industries suitable for the current development of city A include manufacturing, power, alkali gas and water production and supply, transportation, warehousing and postal industry, leasing, and business services. The results of fuzzy k-means clustering algorithm are quite excellent, and the accuracy rate is 93.3%. This paper uses the grey dynamic linear programming model to predict the future development of the Urban A business model and combines the selection of key functions to obtain the best business model: deep and efficient technical equipment as a good goal, achieved through regional logistics, transportation, new services, etc., to enhance the output value of the tertiary industry in city A and optimize the internal structure of the secondary industry in city A.

This study presents a practical method for high-precision Fe isotope determination without column chromatography purification for iron-dominated mineral samples using multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS).

The current analytical methods of stable antimony isotopes are cumbersome and not suitable for rock samples with low antimony content (1 μg/g). In this study, we propose a new protocol for antimony isotopic analysis with a single column of AG50W-X8 resin and antimony standard doping. This method separates antimony effectively from matrices and then mixes it with the Sb standard. As Te does not affect the accuracy of antimony measurement when the Te/Sb ratio is low, we can obtain an accurate Sb isotope composition of the mixture. Then, we can calculate the antimony isotope composition of natural samples. The error propagation of the mixing and calculation processes was evaluated by the Monte Carlo method, and no significant error was found. The antimony isotope compositions were measured using a Thermo Fisher Scientific Neptune Plus multicollector-inductively coupled-mass spectrometry instrument. The instrumental mass bias of Sb isotopes was corrected with a standard-sample bracketing combined with a Sn internal normalization technique. Using the standard doping method, the measured δ

Here, we demonstrate the potential advantages of using isotope tracers to test hypotheses of reaction mechanisms near-equilibrium. Using non-traditional stable Si isotopes as tracers, we measured albite unidirectional dissolution rates (r+) across a range of Gibbs free energy of reaction (ΔrG) close to equilibrium (−26 to −2 kJ/mol). Thirteen batch experiment series were conducted at 50 °C and pH ∼ 8 ± 0.25. Different distances from equilibrium were achieved by a stepwise increase of concentrations of Si (0–600 μM), Al (0–10 μM), and Na (0–1000 μM). The temperature, pH, sample preparation, and reaction duration were kept identical to isolate the ΔrG effect. Secondary phase precipitation, which is difficult to avoid in near-equilibrium, near-neutral pH experiments renders the rate measurement method based on changes in Si and Al concentration unworkable, but it should not impact the Si isotope ratios-based rates. The resulting r+ values were nearly constant in the experimental ΔrG range, signaling no major ΔrG-related switch of reaction mechanisms. Our results suggest that the switch from etch pit opening at far-from-equilibrium to step retreat at near-equilibrium does not operate under circum-neutral pH in low-temperature systems; this mechanism switch was proposed based on experimental data in alkaline solutions at hydrothermal temperatures. The nearly constant r+ values at pH 5–8 also suggest that an H2O-catalyzed reaction mechanism dominant at circumneutral pH, in addition to the H+- and OH–-catalyzed reaction mechanisms dominant at acidic and alkaline pH, respectively. The experimental results have implications for geochemical modeling of low-temperature geological and environmental processes. The results suggest that a term of H2O-catalyzed reaction mechanism should be included in rate laws and that the parallel rate law with a mechanism-switch is not applicable in the pH range of 5–8.

Hydrous minerals in the hybridized zone at the slab-mantle interface play a critical role in retaining and transporting fluid mobile elements in subduction zones. The observed high B and As concentrations and high δ11B values in arc magmas were previously thought to have been resulted from the mechanical transport of forearc serpentinites down to subarc depths by mantle corner flows or through subduction channels because B, As, and Sb are mostly released during early stages of subduction. This study provides new insights into the recycling of B, As, and Sb in subduction zones via an in-situ study on a set of carbonate-bearing serpentinite samples from the Mianlue melange complex in the Qinling Orogen. Petrological observations and bulk-rock Sr-Pb isotopes reveal that the Jianchaling serpentinites were formed by interactions between forearc peridotites and sediment-derived fluids at a shallow depth in the subduction channel. Some Jianchaling serpentinites experienced the lizardite to antigorite transition at 300–400 °C with infiltrations of CO2-rich fluids. In contrast, the Liangyazi antigorite serpentinites were produced at a greater depth. Antigorite grains in the Jianchaling serpentinites have lower Feapfu than those in the Liangyazi serpentinites and most antigorite with geochemical data in the literature. Meanwhile, B, As, and Sb concentrations of Fe-poor antigorite from the Jianchaling serpentines (385–653 ppm B, 198–334 ppm As, and 6.24–8.01 ppm Sb) are not only higher than those of the Fe-rich antigorite from the Liangyazi serpentinites but also 2–3.5 times higher than those of the surrounding lizardite. The lower modal percentage of spinel and ferritchromite in antigorite veinlets, together with the lower bulk-rock FeO content of antigorite-lizardite serpentinites than that of lizardite serpentinites from the Jianchaling region, indicates that some FeO might be lost during the lizardite to antigorite transition. The presence of carbonate minerals in the antigorite veinlets and the remarkably high B, As, and Sb concentrations in the Jianchaling antigorite indicate that the penetrating fluids during the lizardite to antigorite transition are most likely derived from sediment and metabasite decarbonations at

Recent years have witnessed great advancement in visual artificial intelligence (AI) research based on deep learning. To take advantage of deep learning, we need to collect a large amount of data in various environments and conditions. However, collecting such data is time-consuming and labor-intensive. Apart from that, developing and testing visual AI algorithms for multisensory models is expensive and in some cases dangerous processes in the real world. We present PreSim, a 3D environment simulator which provides photo-realistic simulations using a view synthesis module and supports flexible configuration of multimodal sensors to address both of these issues. For our view synthesis module we introduce novel depth refinement, adaptive view selection and layered rendering, to provide realistic imagery. We demonstrate that PreSim has several advantages: (i) it provides a photo-realistic 3D environment which allows seamlessly integrating multisensory models in the virtual world and enables them to perceive and navigate scenes, (ii) it has an internal view synthesis module which allows transforming algorithms developed and tested in simulation to physical platforms without domain adaption, (iii) it can generate a large amount of data for vision-based applications, such as depth estimation and object pose estimation.

Sulfur isotopes are important geochemical tracers in the diverse fields of geosciences. Controlling the accuracy and precision of the microanalysis of sulfur isotopes requires well-characterized reference materials with matrices similar to those of unknown samples. This study introduces a new natural chalcopyrite reference material, TC1725, for S isotope analysis by laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The chalcopyrite grain is homogeneous with respect to S isotopes based on a large number of measurements by LA-MC-ICP-MS and solution nebulizer (SN)-MC-ICP-MS. Isotope ratio mass spectrometry (IRMS) for S isotopic analysis produced a mean δ34SVCDT value of +12.78 ± 0.16‰ (2 s, n = 11). Results of SN-MC-ICP-MS and LA-ICP-MS analyses are consistent with the IRMS ratios within the uncertainty. A total of 981 sulfur isotope ratio spot measurements conducted on the cruciform sections and randomly selected chalcopyrite grains of TC1725 by LA-MC-ICP-MS yielded highly consistent sulfur isotope ratios.

A new simple and rapid method was developed for the purification of Mg from carbonate samples, especially for calcite-rich carbonates. The proposed separation protocol consists of only two types of eluents (4 mol l−1 HNO3 and deionized water) based on 2 ml of DGA resin. 4 ml of HNO3 can effectively separate Mg from calcite-rich carbonates with a high yield within one hour. The Mg elution curve would not drift with different Mg and Ca loading onto the DGA resin. Ca/Mg ratios of the purified samples could be reduced by five orders of magnitude compared to the unpurified calcite-rich carbonate samples. The precision and accuracy of this new method have been evaluated by measurements of the synthetic solution, carbonate standard material, and ten readily available Chinese carbonate reference materials. All the Mg isotopic analytical results were, within analytical uncertainties, essentially identical with the data published previously. Therefore, the new method can be a great option for purifying Mg from carbonate samples for isotopic analysis.

Learning about the regional business model is essential for the sustainable development of the regional economy. From the perspective of urban renewable energy, city A is the product of energy development. This paper analyzes the current situation and existing problems of the industrial model of city A through fuzzy

Here we show that the isotope tracer experimental method for kinetic studies, aided by the recent advance and accessibility of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) analysis for non-traditional stable isotopes, can provide unidirectional dissolution rates at near-equilibrium conditions. For a long time, the only rates available at near-equilibrium were net reaction rates—dissolution rates minus precipitation rates. This is because the conventional experimental method of kinetic studies is based on element concentrations and can only provide net rates. The availability of unidirectional rates allows us to re-examine some fundamental concepts and practices of modeling weathering in geochemistry. In this study, we used the 29Si isotope tracer to conduct albite and K-feldspar dissolution experiments at near-equilibrium conditions in near-neutral pH solutions at 50 °C. Results show that the saturation indices (SI) of solutions approached zero with respect to albite and K-feldspar after ∼240–360 h (h), but 29Si/28Si ratios of the experimental solutions indicated continual dissolution for another 720–1440 h. The rates of total Si precipitation were much smaller than the rates of Si dissolution. The experimental solutions were supersaturated with respect to amorphous Al(OH)3, gibbsite, quartz, allophane, imogolite, and kaolinite. The SI of the solutions remained constant with respect to these phases while Al concentrations slightly decreased and Si concentrations slightly increased, indicating the coupled feldspar dissolution and precipitation of secondary phases, such as albite → amorphous Al(OH)3 + quartz or albite → solution + Al-Si phase(s), instead of significant albite and K-feldspar precipitation (the reverse reaction) at 50 °C. Reaction path modeling of the temporal evolution of Si, Al, Na, and pH revealed that albite dissolution (without significant backward reaction) coupled with the precipitation of a secondary phase with a Si:Al ratio of ∼2:1 can successfully match the experimental data. Given the negligible feldspar precipitation reactions in low-temperature systems (e.g., T

In sample preparation and mass spectrometry analysis, sample dissolution, column chemistry, concentration mismatches, and matrix effects have significant potential for introducing analytical artifacts during Mg isotope analysis. Based on the low MgO content and undesirable matrix elements in felsic rocks, the development of well-characterized felsic standards is essential to reduce inter-laboratory mass bias, enable the assessment of data accuracy, and facilitate the comparison of chemical separation procedures in different laboratories. In this work, the homogeneity and long-term stability of two felsic rock standards, GSR-1 and RGM-2, were evaluated due to their low MgO contents. Furthermore, synthetic solutions with doped matrix elements were used to evaluate potential Mg isotope analytical artifacts using multi-collector inductively coupled plasma mass spectrometry. The accuracy and precision of Mg isotopic compositions in GSR-1 and RGM-2 were assessed by repeated measurements over twelve months. The long-term tests show that the Mg isotopic compositions of the two low MgO felsic rocks (GSR-1 and RGM-2) are homogenous among batches and can be used as low MgO reference materials for accuracy assessments of Mg isotopic analyses. The Mg isotopic compositions (δ26Mg) of GSR-1 and RGM-2 were marked as -0.223‰±0.053‰ (2s, n=50) and -0.184‰±0.058‰ (2s, n=50) respectively.

We have prepared a large volume of pure, concentrated and homogeneous magnesium standard solution (GSB-Mg) to be used as a secondary reference standard by the magnesium isotope community. This new standard solution can also be used for quality assurance, including the development and validation of analytical procedures, preparation and test of analytical methods, quality control and training of analysts. The δ26Mg values relative to DSM3, measured by multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), are −2.038 ± 0.027‰ (n = 45, Lab 1), −2.024 ± 0.055‰ (n = 7, Lab 2), −2.078 ± 0.081‰ (n = 6, Lab 3), −2.037 ± 0.015‰ (n = 8, Lab 4), and −2.067 ± 0.039‰ (n = 12, Lab 5). The δ26Mg and δ25Mg values for the GSB-Mg standard solution are −2.049‰ and −1.056‰, with a combined expanded (k = 2) uncertainty of 0.049‰ and 0.028‰, respectively. These values show higher similarity to Mg isotopic compositions of carbonates and marine sediments compared to those of the mantle and crustal rocks, making the GSB-Mg solution a great reference material for Mg isotopic analysis of carbonates and marine sediments.

Natural water evaporation is a ubiquitous resource at the Earth's surface. Actuating materials that convert such evaporation energy into mechanical motions are highly desirable but challenging. Herein, tough nacre-mimetic films featuring excellent dry/wet tensile strength (294.4 MPa/182.3 MPa) are reported. Benefiting from this feature, the resultant film actuators can not only perform fast flipping motion and lasting oscillation driven by natural evaporation, but also undergo rapid turnover upon exposure to small humidity gradients on the palm of the hand. Importantly, the film actuators further exhibit exceptional actuation without fatigue when exposed to thermal water vapors. Furthermore, it is demonstrated that the stretch-induced oriented film could be used to construct a self-powered soft robot driven by water gradients. As a proof of concept, a natural evaporation-driven generator is assembled by connecting the actuators with a piezoelectric element to power a LED. These demonstrations clearly show that the biomimetic films are promising for harnessing natural evaporation to drive various self-powered devices.

The star tracker is the most accurate attitude measurement device among different types of attitude measurement devices. It is based on captured star images to extract star centroids and then determine attitude. However, images taken by the star tracker under dynamic conditions are often blurred, which limits its dynamic performance. In this paper, we first classify and model motions of the star tracker under dynamic conditions, including rotations and angular vibrations. Then, a motion kernel consisting of three individual descriptors (trajectory, intensity, and point spread function) is proposed to model the motion blurring process and simulate blurred images. Experimental results show that our approach can model a wide variety of blurs including uniform and non-uniform blurs, and it can provide extremely realistic blurred images. These findings are crucial to the subsequent centroid extraction of stars and the dynamic performance of the star tracker.

The Fe isotope ratios can be a useful tracer of geochemistry, biogeochemistry, and the environmental redox state. In this study, we investigated the feasibility of Fe isotopic analysis in Fe-dominated minerals by 193 nm excimer ns laser ablation combined with Nu Plasma 1700 high resolution MC-ICP-MS without matrix-match calibration. Several important instrument parameters were investigated, such as the effect of the addition of nitrogen gas and water vapor, the effects of analytical parameters such as ablation mode, laser fluence, pulse repetition rate, spot size on Fe isotopic mass bias during analysis were investigated as well. The results showed that the effects of ablation mode, spot size, laser pulse repetition rate, and line scan speed can be neglected, while laser fluence and matrix effects had significant influence on the Fe isotopic mass bias at dry plasma condition. These problems can be minimized using consistent lower fluence (1.5‒3.5 J·cm-2), as well as the wet plasma conditions can significantly reduce the matrix effect in Fe isotopic analysis. Fortunately, with the water vapor and nitrogen gas addition after the ablation cell, an accurate and precise Fe isotope in pyrite, manganite, hematite, and chalcopyrite analysis by ns-LA-MC-ICP-MS can be achieved with non-matrix-matched calibration. The obtained accuracy and reproducibility of the in situ determinations of δ56FeIRMM-014 were both better than ± 0.10‰ (2 SD). This study indicated that there was a serious matrix effect in the Fe isotopic analysis of Fe-dominated minerals by ns- LA-MC-ICP-MS, and nitrogen gas mixed with water vapor-assisted ns- LA-MC-ICP-MS were an appealing option for the in situ Fe isotope analysis of Fe-dominated minerals with non-matrix-matched calibration.

The widespread aeolian deposits on the Chinese Loess Plateau (CLP) have been investigated intensively as an outstanding archive of information on past variations of the East Asian Monsoon (EAM). However, differentiating the impacts of precipitation and temperature on loess-based proxies is difficult and complex, which hampers our ability to understand the variability and dynamics of the EAM. In this study, we investigated the Mg isotope composition (δ26Mg) of the secondary carbonates in fine-grained loess samples from ten Holocene profiles and a loess-paleosol sequence, as well as in the primary carbonates of nine loess-source samples from the Asian inland deserts. Our aim was to explore the potential of the δ26Mg values of secondary carbonates in tracing precipitation changes. The results demonstrate that δ26Mg values are homogeneous (−2.07‰) in primary carbonates from different loess-sources, but display large variations in secondary carbonates of loess, increasing from −3.33‰ in the northwest CLP to −1.80‰ in the southeast CLP, and from −3.58‰ during the last glacial to −1.65‰ during the last interglacial. The variations were mainly controlled by EAM precipitation via the migration of isotopically light Mg, because Mg isotope fractionation during the formation of secondary carbonates is temperature insensitive, and the primary carbonate in different loess-sources has relatively constant δ26Mg values. This conclusion is further supported by high correlation (r2 = 0.84) between modern mean annual precipitation (MAP) and δ26Mg in the secondary carbonates of spatial loess samples. Based on this δ26Mg-MAP relationship, temporal variations in MAP were quantitatively estimated, ranging from 670 mm during the last interglacial to 270 mm during the last glacial at the southern CLP. Compared with previous estimates, our MAP exhibits a larger amplitude of glacial-interglacial fluctuations (∼400 mm) with a less uncertainty (53–76 mm), implying that δ26Mg values in secondary carbonates of loess can serve as a novel precipitation proxy to infer EAM variability and dynamics.

Sulfur isotopic composition is useful for tracing sources of ore-forming materials. In situ sulfur isotope analysis by laser ablation coupled with multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) has an advantage over traditional bulk analysis in tracing sources of sulfur in an ore deposit that has complex mineral types and multiple ore-forming processes. However, in using this method, matrix effects exist widely for sulfides from ore deposits. In this work, matrix effects of different sulfides were examined by matrix-unmatched tests, in which the δ34S values of different types of sulfides were calibrated against a laboratory pyrite standard. The results show that the δ34S values of pyrrhotite, chalcopyrite, molybdenite, sphalerite, and arsenopyrite are in agreement with the reference values, suggesting that the matrix effect was negligible. However, a significant matrix effect occurred in the analyses of Ag2S and galena, leading to significant deviations in δ34S values of up to 1.2‰ and 3.2‰, respectively. The matrix effect occurred not only during the laser ablation stage but also during the transition of ions into the mass spectrometer, resulting in significant space charge effects caused by heavy-mass elements. Thus, pyrite can be used as an external bracketing standard for sulfides that do not have a heavy-mass matrix. Based on our matrix-effect study, the following available external standards were selected for the in situ sulfur isotope analysis of complex-type minerals from the Erlihe Zn-Pb deposit. The coarse-grained sphalerite grains (Sph1) and euhedral to subhedral pyrite grains (Py1) from massive ores have δ34S values ranging from 9.2‰ to 18.1‰. Such heavy sulfur isotopic compositions indicate the derivation of sulfur from the deposits of seawater sulfate, related to a thermochemical reducing process. Fine-grained sphalerite (Sph2) and pyrite (Py2) from vein and disseminated ores coexist with pyrrhotite and chalcopyrite, and have relatively light sulfur isotopic compositions, with δ34S values of about 7‰. The slightly positive δ34S values are similar to those of sulfides from sulfide-rich quartz veins, which contain δ34S values of about 4‰, and granodiorite rocks, with δ34S values of about 6‰. Based on previous studies, the light sulfur of the late-stage sulfides may have resulted from a metamorphic or magmatic hydrothermal event during the Indosinian orogeny. In situ sulfur analysis by LA-MC-ICPMS provides new evidence for sources of sulfur from each stage of mineralization in the Erlihe deposit, suggesting that this is a promising method for studying complex ore deposits.

Among various geochemical and petrographic approaches, dolomite crystal morphology and dolostone fabric have been widely applied in the study of ancient dolostones. It is proposed that dolomite crystal morphologies and the rock fabric may reflect the formation temperature, and thus can be used to distinguish different generations of dolomite. However, this scenario has also been challenged by some researchers. In order to test whether the dolomite crystal morphology can be used to differentiate different generations of dolomite, in this study, we measured the Mg isotopic compositions (δ26Mg) of dolomite with different crystal morphologies. δ26Mg of dolomite is controlled by a variety of factors, including temperature, magnesium isotopic composition of dolomitization fluids, and the flow rate of dolomitization fluids. If dolomite with distinct crystal morphologies were derived from different dolomitization processes, it is highly plausible that they would have different δ26Mg. Five types of dolomite with distinct crystal morphologies and rock fabric were recognized from three sampling intervals (S1, S2, and S3) in the middle Ordovician Majiagou Formation in North China. Different types of dolomite in the same sampling interval have similar δ26Mg values, suggesting that these dolomites might have derived during the same dolomitization event. Our study indicates that the crystal morphology alone may not unambiguously differentiate the generations of dolomites. We propose the following reasons: (1) the dolomite crystal morphology might be controlled by various factors rather than the formation temperature alone, or (2) the dolomite crystal morphology might be modified in diagenesis, but δ26Mg remains unchanged.

The continent is the second largest carbon sink on Earth’s surface. With the diversification of vascular land plants in the late Paleozoic, terrestrial organic carbon burial is represented by massive coal formation, while the development of soil profiles would account for both organic and inorganic carbon burial. As compared with soil organic carbon, inorganic carbon burial, collectively known as the soil carbonate, would have a greater impact on the long-term carbon cycle. Soil carbonate would have multiple carbon sources, including dissolution of host calcareous rocks, dissolved inorganic carbon from freshwater, and oxidation of organic matter, but the host calcareous rock dissolution would not cause atmospheric CO2 drawdown. Thus, to evaluate the potential effect of soil carbonate formation on the atmospheric pCO2 level, different carbon sources of soil carbonate should be quantitatively differentiated. In this study, we analyzed the carbon and magnesium isotopes of pedogenic calcite veins developed in a heavily weathered outcrop, consisting of limestone of the early Paleogene Guanzhuang Group in North China. Based on the C and Mg isotope data, we developed a numerical model to quantify the carbon source of calcite veins. The modeling results indicate that 4–37 wt% of carbon in these calcite veins was derived from atmospheric CO2. The low contribution from atmospheric CO2 might be attributed to the host limestone that might have diluted the atmospheric CO2 sink. Nevertheless, taking this value into consideration, it is estimated that soil carbonate formation would lower 1 ppm atmospheric CO2 within 2000 years, i.e., soil carbonate alone would sequester all atmospheric CO2 within 1 million years. Finally, our study suggests the C–Mg isotope system might be a better tool in quantifying the carbon source of soil carbonate.

Coptis chinensis Franch., is a widely used medicinal plant in China. This plant is often contaminated by cadmium (Cd) and render health risk to human consumers. Understanding distribution of Cd and its chemical forms is important to evaluate accumulation of the metal and its detoxification mechanisms in this plant. Since few studies have focused on this aspect, we used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to spatially locate Cd in rhizome cross-sections, and ICP-MS to analyze the Cd subcellular distribution and the chemical forms of Cd in different tissues. Rhizome bioimaging results showed that Cd was distributed predominantly within the periderm, cortex, pith, and root trace vascular bundle. The LA-ICP-MS results suggested that Ca2+ channels might be a pathway for Cd entry into the plant. Subcellular distribution data indicated that most of Cd was associated with the cell wall (41.8-77.1%) and the soluble fraction (14.4-52.7%) in all tissues. Analysis of chemical forms revealed that majority Cd existed in less mobile and less toxic forms in all tissues, and P could convert to insoluble phosphate with Cd to moderate Cd toxicity. The new understanding of Cd accumulation and detoxification might provide novel strategies for reducing the levels of Cd in C. chinensis Franch., thereby mitigating its potential transfer to humans and providing a theoretical basis for evaluating the Cd status in other medicinal plants. Further, our findings might provide a basis for establishing a reasonable Cd limit level of traditional Chinese medicinal materials.

This study presents a practical method for high-precision Mg isotope determination without column chromatography for carbonate samples using sulphuric acid and MC-ICP-MS. The protocol uses the chemical reaction between carbonates and sulphuric acid to generate a CaSO4 precipitate and MgSO4 supernatant, which are used to determine Mg isotopic ratios. The matrix effects and the sulphuric acid conditions were rigorously examined using a Nu Plasma II in wet plasma mode. The precision and accuracy of this method were tested by measurements of the carbonite standard material JDo-1 over four months. The δ26Mg of JDo-1 is −2.32 ± 0.11‰ (2SD, n = 34) relative to DSM3, well consistent with the recommended value (−2.35 ± 0.15‰). The robustness of this method was further assessed by replicated analyses of ten Chinese carbonate reference materials that covered a large range of MgO contents from 5.98 wt% to 20.91 wt%.

This study presents a chemical protocol for the separation of Mg that is particularly adapted for diverse igneous rock samples, especially for high-K and low-Mg rocks. This protocol is based on a combination of three procedures: the removal of K from the samples using the precipitation procedure, followed by the separation of Fe and Ca using 2 mL of AG50W-X12 cation exchange resin, and finally the removal of Al, Ti, Na, and Fe elements using 0.5 mL of AG50W-X12 cation exchange resin. The effect of acidity and concentration mismatch as well as the matrix effect were rigorously evaluated using Nu Plasma II MC-ICP-MS with a wet plasma mode. The δ26Mg mean values of the GSB and Alfa Mg standard solutions are −2.05 ± 0.05‰ (2 standard deviation (2s), n = 106) and −3.91 ± 0.04‰ (2s, n = 51), respectively, which serve as in-house Mg standards in the State Key Laboratory of Continental Dynamics (SKLCD). The average δ26Mg value of one multi-elemental Mg standard GSB-1, made by adopting GSB with matrix elements, agrees well with the recommended value after precipitation and chromatographic separation. The long-term reproducibility, assessed by repeated measurements of Mg standard solutions and reference materials (RMs), is ±0.06‰. The robustness of our method is further assessed by the replicated analyses of fifteen rock standards and olivine grains with large variations in MgO and K2O content.

In this work, we improved the sensitivity of a multi-collector-inductively coupled plasma mass spectrometry system by increasing the vacuum of the expansion chamber using a high-speed EH mechanical booster pump (EH500, 500 m3 h−1, BOC Edwards) in conjunction with a standard E2M80 pump (80 m3 h−1, BOC Edwards). The vacuum was improved from 1.0 mbar to less than 0.5 mbar. The sample ion yield for heavy isotopes, such as those of Pb, was improved from 0.047% to 0.072% in the wet-plasma mode (sample uptake rate, 113 μL min−1), and from 1.35% to 1.84% in the dry-plasma mode (sample uptake rate 105 μL min−1); the variation in the background intensity was less than 1.3 mV for all the Faraday cups. Thus, the sample ion yield in the wet-plasma mode was enhanced more effectively than that in the dry-plasma mode owing to a slightly larger orifice in the wet cone setup. The accuracies for all the isotopes tested, including those of non-traditional metal ones, in both modes were identical to previously published data within an error of 2 s. These results indicate that improving the vacuum at the interface has no effect on the accuracy of isotope measurements and is an effective method for improving the detectability of isotopic compositions for bulk solution analysis with low element contents and the spatial resolution for measurements performed using the laser-ablation sampling technique. This work could provide an alternative for laboratories with a similar device, when tackling samples with low contents.

Aeschynanthus pulcher (Blume) G. Don, the “lipstick plant” is a prized ornamental plant with distinctive flowers. Here, we introduce a novel in vitro regeneration method for A. pulcher using leaf explants and an optimized combination of phytohormone plant growth regulators (PGRs). The optimal conditions for shoot regeneration included 1 mg L−1 polyvinyl pyrrolidone (PVP) plus 3 mg L−1 thidiazuron (TDZ), inducing a response rate of 82.4% and a shoot/explant ratio of 38.6. When the Murashige and Skoog (MS) medium contained indole-3-butyric acid (IBA) alone, leaves first differentiated into adventitious roots and then adventitious shoots. Leaves cultured on MS medium containing 1 g L−1 PVP, 3 mg L−1 TDZ, 5 mg L−1 casein, and 0.1 mg L−1 α-naphthaleneacetic acid (NAA) for 30 d exhibited the highest embryogenic callus (EC) induction rate (95.6%). The optimal shoot proliferation coefficient (21.5) was obtained when shoots derived from EC were cultured on the same medium as that used for EC induction for 5 weeks. The most effective medium for rooting of elongated shoots was MS medium containing 1 g L−1 PVP, 5 mg L−1 casein, 3 mg L−1 6-benzyladenine (BA), and 0.1 mg L−1 NAA, and the number of roots reached 18.8. The regenerated plants grown in a greenhouse had 100% survival following one week of hardening. Overall, our effective and efficient propagation method should result in shortened culture periods and reduced production costs, allowing for the future selective breeding and genetic improvement of A. pulcher.

Recent years have witnessed great advancement in visual artificial intelligence (AI) research based on deep learning. To take advantage of deep learning, we need to collect a large amount of data in various environments and conditions. However, collecting such data is a time-consuming and labor-intensive task. Apart from that, developing and testing visual AI algorithms for robots are expensive and in some cases dangerous processes in the real world. To address these challenges, in this thesis we investigate algorithms to design a high-quality simulator for mobile robots. We aim to narrow the gap between simulation and reality, generate infinitely many photo-realistic color-and-depth image pairs from arbitrary locations and allow transferring algorithms that are developed and tested in simulation to physical platforms without domain constraints. To achieve our goals, we design a view synthesis module used for our simulator to synthesize free-viewpoint photo-realistic color-and-depth image pairs. Our approach combines depth refinement, adaptive view selection and layered 3D warping to lower the rendering complexity and improve the quality of synthesized images. We also design controller, recorder, and visualizer modules for our simulator. These modules are designed to work together, providing a variety of data including real-time camera poses, synthesized color-and-depth image pairs, trajectories of the robot for training robotic tasks. Based on our simulator, we build a 3D dataset for benchmarking 6D object pose estimation which pays an important role in robotic grasping and manipulation research. The dataset consists of different objects that cover a variety of shapes, rigidity, sizes, weight and textures. For our simulator can seamlessly integrate robots with virtual scenes, we generate a large number of photo-realistic color-and-depth image pairs with ground truth 6D poses for training data-driven pose estimation approaches. Our dataset is freely distributed to research groups worldwide by the Shape Retrieval Challenge (SHREC) benchmark on 6D pose estimation. We conduct a variety of experiments to investigate the performance of different pose estimation approaches proposed from our benchmark using different evaluation metrics. We learn important lessons from the current pose estimation algorithms. This gives insight into where researchers' attention should be paid to make progress on pose estimation. Apart from that, we propose a novel approach to further improve the performance of 6D object pose estimation by effectively computing hidden representations from color and depth images, and then fusing them properly with a graph attention network which fully exploits the relationship between visual and geometric features. Overall, we propose a 3D photo-realistic virtual environment simulator to develop vision-based algorithms for AI research. Experiments demonstrate our simulator narrows the reality gap between the virtual environment and the real scene. Thus, computer vision-based algorithms including depth estimation, object recognition and 6D object pose estimation developed in simulation can be transferred to the real world without domain adaption.

Deep learning has achieved great success on robotic vision tasks. However, when compared with other vision-based tasks, it is difficult to collect a representative and sufficiently large training set for six-dimensional (6D) object pose estimation, due to the inherent difficulty of data collection. In this paper, we propose the RobotP dataset consisting of commonly used objects for benchmarking in 6D object pose estimation. To create the dataset, we apply a 3D reconstruction pipeline to produce high-quality depth images, ground truth poses, and 3D models for well-selected objects. Subsequently, based on the generated data, we produce object segmentation masks and two-dimensional (2D) bounding boxes automatically. To further enrich the data, we synthesize a large number of photo-realistic color-and-depth image pairs with ground truth 6D poses. Our dataset is freely distributed to research groups by the Shape Retrieval Challenge benchmark on 6D pose estimation. Based on our benchmark, different learning-based approaches are trained and tested by the unified dataset. The evaluation results indicate that there is considerable room for improvement in 6D object pose estimation, particularly for objects with dark colors, and photo-realistic images are helpful in increasing the performance of pose estimation algorithms.

The 6D object pose is widely applied in robotic grasping, virtual reality and visual navigation. However, heavy occlusion, changing light conditions and cluttered scenes make this problem challenging. To address these issues, we propose a novel approach that effectively extracts color and depth features from RGB-D images considering the local and global geometric relationships. After that, we apply a graph attention mechanism to fully exploit representations between these features and then fuse them together to predict the 6D pose of a given object. The evaluation results indicate that our method significantly improves the accuracy of the estimated 6D pose and achieves the state-of-the-art performance on LineMOD, YCB-Video, and a new dataset. Ablation studies demonstrate the effect of our network modules.

This study performed a series of comparable experiments (with or without column chromatography) to evaluate whether non-deviated Cu isotope ratios can be obtained directly by Nu Plasma II multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) using standard-sample bracketing with Ga as internal mass bias correction model (C-SSBIN) without column chromatography. Twelve Cu-dominated minerals (copper plate, native copper, chalcopyrite, bornite, chalcocite, digenite, covellite, tetrahedrite, azurite, malachite, atacamite, and cyanotrichite) displayed little drift in δ65Cu values compared with those of minerals with column chromatography, with Δδ65Cuwithout−with ranging from −0.04 to +0.02‰. This means that Cu isotope ratios in Cu-dominated minerals can be achieved without column chromatography, due to the simple matrix and the stability of the machine by using C-SSBIN mode. The acidity and internal standard concentration mismatch effects, as well as the matrix effect, were strictly assessed by Nu Plasma II MC-ICP-MS in a wet-plasma mode in the State Key Laboratory of Continental Dynamics (SKLCD). Finally, a long-term reproducibility of better than ±0.03‰ [n = 38, 2 standard deviations (2s)] were achieved by repeatedly measuring chalcopyrite without column chromatography over 4 months.

Radio frequency (RF) fingerprinting is a process of identifying a device or annunciator. Because of the specificity of the wireless transmitting circuit and the imperfections of the components that make up the transmitting circuit, it is possible to extract the RF fingerprint used to identify the wireless transmitter from the wireless signal. At present, the traditional RF fingerprint identification method is performed based on a preset determination formula, and there are problems such as high prior information requirement and limited application range. To solve these problems, this paper proposes a RF fingerprint recognition method based on convolutional neural network (CNN). The research focuses on three aspects: RF fingerprint extraction, convolutional neural network design and wireless transmitter identification and verification. The result proves that this method can complete the wireless transmitter identification well.