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121篇 您的检索式:作者名="Weigang Wang"
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1Progress and Prospects of Salt Lake Research in China显示文摘China has unique salt lake resources, and they are distributed in the east of Eurasian salt lake subzone of the Northern Hemisphere Salt Lake Zone, mainly concentrated in the regions with modern mean annual precipitation lower than 500 mm. This paper preliminarily reviews the progress made in salt lake research in China for the past 60 years. In the research of Paleoclimate and paleoenvironment from salt lake sediments, a series of salts have been proposed to be indicators of paleoclimate, and have been well accepted by scholars. The chloride-sulfate depositional regions of the west Qaidam and the east Tarim have been revealed to be the drought center of China since the Quaternary, and more than 6 spreading stages of arid climate(salt forming) have been identified. Five pan-lake periods with highstands have been proved to exist during the late Quaternary on the Tibetan Plateau. In mineral resource prospecting and theories of the forming of salt deposits: the atlas(1:2500000) of hydrochemical zoning of salt lakes on the Tibetan Plateau has been compiled for the first time, revealing the zonal distribution and transition from carbonate type to chloride type from south to north and presenting corresponding mineral assemblages for different type of salt lakes; several large continental salt deposits have been discovered and the theory of continental potash deposition has been developed, including the salt deposition in deep basins surrounded by high mountains, the mineral deposition from multistage evolution through chains of moderate or shallow lakes with multilevels, the origin of potassium rich brines in gravel layers, and the forming of potassium deposits through the inheriting from ancient salt deposits, thus establishing the framework of 'Continental Potash Deposition Theory'; several new types of Mg-borate deposits have been discovered, including the ulexite and pinnoite bed in Da Qaidam Lake, Qinghai, the pinnoite and kurnakovite bed in Chagcam Caka, Tibet, the kurnakovite bed in Lake Nyer, and the corresponding model of borate deposition from the cooling and dissolution of boron rich brines was proposed based on principles of geology, physics and chemistry. The anti-floatation-cold crystallization method developed independently has improved the capacity of KCl production to 3 million tons per year for the Qarham, serving the famous brand of potash fertilizer products. One 1.2 million ton K-sulfate production line, the biggest in the world, has been built in Lop Nor, and K-sulfate of about 1.6 million tons was produced in 2015. Supported by the new technology, i.e. brine preparation in winter-cooling-solarization-isolation-lithium deposition from salt gradient solar pond' the highest lithium production base at Zabuye Lake(4421 m), Tibet, has been established, which is the first lithium production base in China that reaches the year production of 5000 tons of lithium carbonate. The concept of Salt lake agriculture(Salt land agriculture) has been established based on the mass growth of Dunaliella and other bacillus-algae and the occurrence of various halophytes in saltmarsh and salt saline-alkali lands, finding a new way to increase arable lands and develop related green industry in salt rich environments. Finally this paper presents some new thoughts for the further research and development on salt science, and the further progress in salt science and technology will facilitate the maturing of the interdisciplinary science 'Salinology'.ZHENG Mianping ZHANG Yongsheng LIU Xifang NIE Zhen KONG Fanjing QI Wen Jia Qingxian PU Linzhong HOU Xianhua WANG Hailei ZHANG Zhen KONG Weigang LIN Yongjie 2016Acta Geologica Sinica(English Edition)2016,90,4:15
2TOA-Based NLOS Error Mitigation Algorithm for 3D Indoor Localization显示文摘In the process of indoor localization,the existence of the non-line of sight(NLOS)error will greatly reduce the localization accuracy.To reduce the impact of this error,a 3 dimensional(3D)indoor localization algorithm named LMR(LLS-Minimum-Residual)is proposed in this paper.We first estimate the NLOS error and use it to correct the measurement distances,and then calculate the target location with linear least squares(LLS)solution.The final nodes location can be obtained accurately by NLOS error mitigation.Our algorithm can work efficiently in both indoor 2D and 3D environments.The simulation results show that the proposed algorithm has better performance than traditional algorithms and it can significantly improve the localization accuracy.Weigang Wang Yunwei Zhang Longbin Tian 2020China Communications2020,17,1:13
3Security information factor based airborne radar RF stealth显示文摘Radar radio frequency(RF) stealth is very important in electronic war(EW), and waveform design and selection. Existing evaluation rules of radar RF stealth include too many parameters of radar and interceptors, such as Schleher interception factor,which makes it difficult to evaluate radar RF stealth technologies if interceptor parameters are unknown. In communication, security capacity has been presented to describe the possible ability to communicate in complete security. Since the essential of the security capacity is to have the interceptor get none valued information from the emitter, this paper is proposed to study security information factors taking advantage of mutual information to evaluate radar RF stealth under some conditions. Through analyzing mutual information obtained by the radar and the interceptor, this paper defines the security information factor with and without cooperative jamming. Furthermore, this paper deduces the ratio of the match filter to the match incoherent filter and discuss mutual information received by the interceptor. Numerical simulations illustrate radar RF stealth effects based on the security information factor concept under different conditions.Fei Wang Mathini Sellathurai Weigang Liu Jiangjiang Zhou 2015Journal of Systems Engineering and Electronics2015,26,2:9
4Improvement on On-line Ferrograph Image Identification显示文摘A newly developed on-line visual ferrograph(OLVF) gives a new way for engine wear state monitoring. However, the reliability of on-line wear debris image processing is challenged in both monitoring ship engines and the Caterpillar bench test, which weren’t reported in previous studies. Two problems were encountered in monitoring engines and processing images. First, small wear debris becomes hard to be identified from the image background after monitoring for a period of time. Second, the identification accuracy for wear debris is greatly reduced by background noise because of oil getting dark after running a period of time. Therefore, the methods adopted in image processing are examined. Two main reasons for the problems in wear debris identification are generalized as follows. Generally, the binary threshold was determined by global image pixels, and was easily affected by the non-objective zone in the image. The boundary of the objective zone in the binary image was misrecognized because of oil color becoming lighter during monitoring. Accordingly, improvements were made as follows. The objective zone in a global binary image was identified by scanning a column of pixels, and then a secondary binary process confined in the objective zone was carried out to identify small wear debris. Linear filtering with a specific template was used to depress noise in a binary image, and then a low-pass filtering was performed to eliminate the residual noise. Furthermore,the morphology parameters of single wear debris were extracted by separating each wear debris by a gray stack, and two indexes, WRWR (relative wear rate) and WRWS (relative wear severity), were proposed for wear description. New indexes were provided for on-line monitoring of engines.WU Tonghai WANG Weigang WU Jiaoyi MAO Junhong XIE Youbai 2010Chinese Journal of Mechanical Engineering2010,23,1:8
5Newly discovered Palaeolithic artefacts from loess deposits and their ages in Lantian,central China显示文摘Eight new Palaeolithic open-air sites were identified and 770 stone artefacts were collected from 2009 to 2011 in the Lantian area of the Bahe River valley, central China. Because the famous Homo erectus fossils were unearthed at the Gongwangling and Chenjiawo localities, and more than 30 Palaeolithic open-air sites were investigated in the 1960s in this region, the catchment of Bahe River is regarded as one of the most important hominin sites from the late early Pleistocene to the middle Pleistocene. These eight newly discovered open-air sites are located at the second(n = 6), third(n = 1) or higher terraces(n = 1) of the Bahe River. The Diaozhai section on the second terrace was sampled in detail. Two samples were collected for optically stimulated luminescence dating(OSL). The OSL results suggest that a buried lithic artefact layer at the Diaozhai site spans approximately 70–30 ka. The lithic assemblage analysis suggests that the stone artefacts were made of local pebbles/cobbles such as greywacke, quartz, sandstone and igneous rocks. The main percussion techniques that were used were direct hard hammer percussion and bi-polar techniques. The lithic artefacts comprise hammer stones, cores, flakes, retouched tools and flaking debris. Acheulian-type large cutting tools(LCTs) such as hand-axes, picks and cleavers were indentified in the Lantian region as well. This is the first time Acheulian-type LCTs from the late Pleistocene have been identified in this region. This study distinguishes age gaps between Western world and East Asian Acheulian-type tools.Shejiang Wang Huayu Lu Hongyan Zhang Xuefeng Sun Shuangwen Yi Yingyong Chen Gaike Zhang Luda Xing Weigang Sun 2014Chinese Science Bulletin2014,59,7:7
6Heterogeneous uptake of nitrogen dioxide on Chinese mineral dust显示文摘Mineral dust is one of the major aerosols in the atmosphere.To assess its impact on trace atmospheric gases,in this work we present a laboratory study of the effect of temperature on the heterogeneous reaction of NO_2 on the surface of ambient Chinese dust over the temperature range from 258 to 313 K.The results suggest that nitrogen dioxide could mainly be adsorbed on these types of Chinese mineral dust reversibly with little temperature dependence.Similar to a previous study on NO_2 uptake on mineral aerosols,the uptake coefficients are mainly on the order of 10^(-6) for the Chinese dust,when BET areas are taken into account.HONO was observed as a product,and its formation and decomposition on Chinese mineral dust during the uptake processes were also studied.The complete dataset from this study was compiled with previous literature determinations.Atmospheric implications of the heterogeneous reaction between NO_2 and mineral dust are also discussed,in an effort to understand this important heterogeneous process.Li Zhou Weigang Wang Siqi Hou Shengrui Tong Maofa Ge 2015Journal of Environmental Sciences2015,27,12:6
7Motion Error Compensation of Multi-legged Walking Robots显示文摘Existing errors in the structure and kinematic parameters of multi-legged walking robots,the motion trajectory of robot will diverge from the ideal sports requirements in movement.Since the existing error compensation is usually used for control compensation of manipulator arm,the error compensation of multi-legged robots has seldom been explored.In order to reduce the kinematic error of robots,a motion error compensation method based on the feedforward for multi-legged mobile robots is proposed to improve motion precision of a mobile robot.The locus error of a robot body is measured,when robot moves along a given track.Error of driven joint variables is obtained by error calculation model in terms of the locus error of robot body.Error value is used to compensate driven joint variables and modify control model of robot,which can drive the robots following control model modified.The model of the relation between robot's locus errors and kinematic variables errors is set up to achieve the kinematic error compensation.On the basis of the inverse kinematics of a multi-legged walking robot,the relation between error of the motion trajectory and driven joint variables of robots is discussed.Moreover,the equation set is obtained,which expresses relation among error of driven joint variables,structure parameters and error of robot's locus.Take MiniQuad as an example,when the robot MiniQuad moves following beeline tread,motion error compensation is studied.The actual locus errors of the robot body are measured before and after compensation in the test.According to the test,variations of the actual coordinate value of the robot centroid in x-direction and z-direction are reduced more than one time.The kinematic errors of robot body are reduced effectively by the use of the motion error compensation method based on the feedforward.WANG Liangwen CHEN Xuedong WANG Xinjie TANG Weigang SUN Yi PAN Chunmei 2012Chinese Journal of Mechanical Engineering2012,25,4:6
8Light absorption properties and potential sources of brown carbon in Fenwei Plain during winter 2018–2019显示文摘A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.Wenyu Zhang Weigang Wang Jie Li Shuangliang Ma Chaofan Lian Kun Li Bo Shi Mingyuan Liu Yanyu Li QingQing Wang Yele Sun Shengrui Tong Maofa Ge 2021Journal of Environmental Sciences2021,33,4:6
9Fatigue behavior of direct laser deposited Ti-6.5Al-2Zr-1Mo-1V titanium alloy and its life distribution model显示文摘The present work aims to investigate the fatigue behavior of Direct Laser Deposition(DLD) Ti-6.5 Al-2 Zr-1 Mo-1 V titanium alloy under constant amplitude stress. 22 pieces of DLD Ti-6.5 Al-2 Zr-1 Mo-1 V titanium alloy standard cylinder specimens were tested under a stress level of 800 MPa with a stress ratio of 0.06. Fatigue fractography and fatigue life data were obtained.Through the fracture surface analysis, the specimens were divided into two categories in accordance with the location of crack initiation and defect types. Comparison of fatigue life and behavior between two specimen types was given, which was followed by a discussion about the impact of defect type, size and position on the fatigue life of the specimen. The fatigue test results also show a large variation of fatigue life. To illustrate the statistical characteristics of the fatigue life, probabilistic analysis was performed, and a novel bimodal lognormal model was established. The model has a good fit with the experimental data and can reduce the scatter of the fatigue life significantly.Xiaofan HE Tianshuai WANG Xiaobo WANG Weigang ZHAN Yuhai LI 2018Chinese Journal of Aeronautics2018,31,11:5
10Erasure-Correction-Enhanced Iterative Decoding for LDPC-RS Product Codes显示文摘Low-density parity-check(LDPC)codes are widely used due to their significant errorcorrection capability and linear decoding complexity.However,it is not sufficient for LDPC codes to satisfy the ultra low bit error rate(BER)requirement of next-generation ultra-high-speed communications due to the error floor phenomenon.According to the residual error characteristics of LDPC codes,we consider using the high rate Reed-Solomon(RS)codes as the outer codes to construct LDPC-RS product codes to eliminate the error floor and propose the hybrid error-erasure-correction decoding algorithm for the outer code to exploit erasure-correction capability effectively.Furthermore,the overall performance of product codes is improved using iteration between outer and inner codes.Simulation results validate that BER of the product code with the proposed hybrid algorithm is lower than that of the product code with no erasure correction.Compared with other product codes using LDPC codes,the proposed LDPC-RS product code with the same code rate has much better performance and smaller rate loss attributed to the maximum distance separable(MDS)property and significant erasure-correction capability of RS codes.Weigang Chen Ting Wang Changcai Han Jinsheng Yang 2021China Communications2021,18,1:5
11Chemical Characteristics and Environmental Records of a Snow-Pit at the Glacier No.12 in the Laohugou Valley, Qilian Mountains显示文摘In June 2006, samples were collected from a 90 cm snow-pit at an elevation of 5 040 m a.s.l. in the northern branch firn basin of the Glacier No. 12, Laohugou Valley, in the western part of Qilian Mountain, China. Oxygen isotopes(δ18O) and major soluble ions were measured. Results showed that Ca2+ is the dominant cation, and SO42- is the dominant anion. All major ions have close positive correlations with eachother except NO3- and NH4+. δ18O show positive correlation with air temperature. The method of correlation analysis, sea-salt ion tracer and trend analysis were used to determine the source of the chemical components. The correlation analysis and HYSPLIT backward trajectory analysis suggest that atmospheric soluble dust species dominate the chemical signature.Xiaoqing Cui Jiawen Ren Xiang Qin Weijun Sun Guangming Yu Zebin Wang Weigang Liu 2014Journal of Earth Science2014,25,2:4
12Development and application of the multi-wavelength cavity ring-down aerosol extinction spectrometer显示文摘To better characterize the optical properties of atmospheric aerosols, the multi-wavelength cavity ring-down aerosol extinction spectrometer(MCRD-AES) is developed and applied in this study. By using tunable light source and four parallel cavities, the MCRD-AES covers a wide and atmospherically relevant wavelength range from 360 to 663 nm. Four wavelengths(375 nm, 440 nm, 532 nm, and 620 nm) are particularly tested with ammonium sulfate and nigrosine. The refractive index values obtained from this study agree well with literature data. The stability and accuracy of the MCRD-AES are tested, and the minimum detectable extinction coefficient is 0.5 1/Mm. The high sensitivity, high precision, and wavelength changeable of MCRD-AES indicate its great application prospect in comprehensively quantifying the optical properties of atmospheric aerosols.Junling Li Weigang Wang Kun Li Wenyu Zhang Maofa Ge Chao Peng 2019Journal of Environmental Sciences2019,31,2:4
13Sequencing barcode construction and identification methods based on block error-correction codes显示文摘Multiplexed sequencing relies on specific sample labels,the barcodes,to tag DNA fragments belonging to different samples and to separate the output of the sequencers.However,the barcodes are often corrupted by insertion,deletion and substitution errors introduced during sequencing,which may lead to sample misassignment.In this paper,we propose a barcode construction method,which combines a block error-correction code with a predetermined pseudorandom sequence to generate a base sequence for labeling different samples.Furthermore,to identify the corrupted barcodes for assigning reads to their respective samples,we present a soft decision identification method that consists of inner decoding and outer decoding.The inner decoder establishes the hidden Markov model(HMM)for base insertion/deletion estimation with the pseudorandom sequence,and adapts the forward-backward(FB)algorithm to output the soft information of each bit in the block code.The outer decoder performs soft decision decoding using the soft information to effectively correct multiple errors in the barcodes.Simulation results show that the proposed methods are highly robust to high error rates of insertions,deletions and substitutions in the barcodes.In addition,compared with the inner decoding algorithm of the barcodes based on watermarks,the proposed inner decoding algorithm can greatly reduce the decoding complexity.Weigang Chen Lixia Wang Mingzhe Han Changcai Han Bingzhi Li 2020Science China(Life Sciences)2020,63,10:4
14Extinction efficiencies of mixed aerosols measured by aerosol cavity ring down spectrometry显示文摘A cavity ring down spectroscopy instrument was introduced and designed for measuring extinction efficiencies of pure and mixing aerosols in this paper.Through averaging 500 individual waveforms,the minimal detectable aerosol extinction coefficient of 8.4 × 10-7 m-1 was achieved.By the test results using the NaCl particles,we concluded that this system could measure the extinction efficiencies of an aerosol with an uncertainty less than 3% under laboratory controlled experimental conditions.The refractive indices of different aerosols were retrieved through comparing the measured extinction efficiencies of each aerosol type with which predicted by Mie theory.Aerosols composed of ammonium sulphate and succinic acid with different weight ratios were used to create a model of mixed aerosols using these two materials,whose extinction efficiencies and complex refractive indices were derived.The refractive indices of the mixed aerosols were also calculated by various optical mixing rules.We found that all the molar refraction/absorption mixing rule,the volume ratio linear rule,and Maxwell-Garnett rule did provide comparable results,of which the volume ratio linear rule gave a slightly worse fit than the others.WANG Lei WANG WeiGang GE MaoFa 2012Chinese Science Bulletin2012,57,20:4
15Dual-Wavelength Laser Flash Raman Spectroscopy Method for In-Situ Measurements of the Thermal Diffusivity: Principle and Experimental Verification显示文摘This paper presents an in-situ, non-contact, non-destructive 'dual-wavelength laser flash Raman spectroscopy method' for measuring the thermal diffusivity. In this method, a heating pulse is used to heat the sample and another pulsed laser with a different wavelength and negligible heating effect is used as a probe to measure the sample temperature changes during the heating and cooling periods from the Raman peak shifts. The sample temperature rise and fall curves are measured by changing the delay between the heating pulse and the probing pulse with the thermal diffusivity then characterized by fitting the temperature curves. The time delay between the heating and probing pulses can be precisely controlled with a minimum step of 100 ps. Hence, the temperature variation can be scanned with an ultra-high temporal resolution of up to 100 ps, which significantly improves the measurement accuracy of transient thermal parameters. The measurement accuracy of this method has been verified using a bulk material model and experiments. The measured thermal diffusivity of a silicon sample has been obtained to be 8.8×10^(-5 )m^2/s with a 3% difference between the measured value and the average result for bulk silicon in the literature which verifies the reliability and accuracy of this method.FAN Aoran HU Yudong MA Weigang WANG Haidong ZHANG Xing 2019Journal of Thermal Science2019,28,2:4
16Knudsen cell and smog chamber study of the heterogeneous uptake of sulfur dioxide on Chinese mineral dust显示文摘The heterogeneous uptake processes of sulfur dioxide on two types of Chinese mineral dust(Inner Mongolia desert dust and Xinjiang sierozem)were investigated using both Knudsen cell and smog chamber system.The temperature dependence of the uptake coefficients was studied over a range from 253 to 313 K using the Knudsen cell reactor,the initial uptake coefficients decreased with the increasing of temperature for these two mineral dust samples,whereas the steady state uptake coefficients of the Xinjiang sierozem increased with the temperature increasing,and these temperature dependence functions were obtained for the first time.In the smog chamber experiments at room temperature,the steady state uptake coefficients of SO2decreased evidently with the increasing of sulfur dioxide initial concentration from 1.72×1012to 6.15×1012mol/cm3.Humid air had effect on the steady state uptake coefficients of SO2onto Inner Mongolia desert dust.Consequences about the understanding of the uptake processes onto mineral dust samples and the environmental implication were also discussed.Li Zhou Weigang Wang Yanbo Gai Maofa Ge 2014Journal of Environmental Sciences2014,26,12:3
17Involvement of Ghrelin-Growth Hormone Secretagogue Receptor System in Pathoclinical Profiles of Digestive System Cancer显示文摘Ghrelin 受体被显示了沿着人的胃肠的道被表示。最近的研究证明 ghrelin 和合成 ghrelin 受体收缩筋改进了重量获得和瘦身体质量在由对 ghrelin 受体起作用的癌症极度瘦弱的一个老鼠模型的保留,也就是说生长荷尔蒙促泌素受体(GHS-R ) 。这研究试图在人的胃肠的道癌症探索表示和 ghrelin 受体的分发并且在人的消化癌症调查 ghrelin-GHS-R 系统的可能的参与。外科的人的消化癌症标本从不同病人从胃肠的道的各种各样的部分被获得。在这些纸巾的 ghrelin 受体的表达式被织物检测微数组技术。我们的结果证明那 ghrelin 受体在整个胃肠的道在癌症被表示,主要在 mucosal 层房间的细胞质。它的表示水平可能与病人的机关类型,组织学的等级, tumor-nodes-metastases 阶段,和营养地位(重量损失) 相关。第一次,我们在消化系统癌症识别了 ghrelin 受体的分发。我们的结果暗示 ghrelin-GHS-R 系统可能涉及消化癌症的 pathoclinical 侧面。Zhigang WANG Weigang WANG Wencai QIU Youben FAN Jun ZHAO Yu WANG Qi ZHENG 2007Acta Biochimica et Biophysica Sinica2007,39,12:3
18Continuous and comprehensive atmospheric observations in Beijing:a station to understand the complex urban atmospheric environment显示文摘Due to profound impact on climate and human health,air quality has attracted attention from all levels of the civil society.The key step in the provision of required tools for the society to tackle the complex air quality problem is to characterize it in a comprehensive manner with a long-term perspective.Here,we describe a continuous and comprehensive observation station and its accompanying state-ofthe-art instrumentation that was established to investigate the complex urban atmospheric environment in a rapidly developing Chinese Megacity.The station,located in downtown Beijing,aims to study air quality by identifying the major atmospheric pollutants and key processes determining their formation and loss mechanisms.A few hundreds of parameters are continuously measured with the state-of-the-art instruments,including trace gas concentrations,aerosol particle size distributions,and mass concentrations,covering aerosol particle chemical composition from molecules to micrometer-sized aerosol particles.This produced long-term,comprehensive big data with around 1�10^(11)bytes per year.In this paper,we provide an overview on the facilities of the station,the instrumentation used,the workflow of continuous observations and examples of results from 2018 to 2019 and a basis for establishing a modern long-term,comprehensive atmospheric urban observation station in other megacities.Yongchun Liu Chao Yan Zemin Feng Feixue Zheng Xiaolong Fan Yusheng Zhang Chang Li Ying Zhou Zhuohui Lin Yishou Guo Ying Zhang Li Ma Wenshuo Zhou Zhikun Liu Lubna Dada Kaspar Dallenbach Jenni Kontkanen Runlong Cai Tommy Chan Biwu Chu Wei Du Lei Yao Yonghong Wang Jing Cai Juha Kangasluoma Tom Kokkonen Joni Kujansuu Anton Rusanen Chenjuan Deng Yueyun Fu Rujing Yin Xiaoxiao Li Yiqun Lu Yiliang Liu Chaofan Lian Dongsen Yang Weigang Wang Maofa Ge Yuesi Wang Douglas R.Worsnop Heikki Junninen Hong He Veli-Matti Kerminen Jun Zheng Lin Wang Jingkun Jiang Tuukka Petaja Federico Bianchi Markku Kulmala 2020Big Earth Data2020,4,3:3
19Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water显示文摘Metabolites of algae such as geosmin, 2- methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientifc attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. Reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also dis- cussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg. L~ and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant k -- 0.00213 L.(min.mg)-1. Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO4 dosage, but dramatically dropped with the increasing levels of humic acid (1.8-4.5 mg. L-1) and other odor-causing compounds (e.g. fl-cyclocitral, 0-1886.0 pg.L-1). Solution pH (5.2- 9.0) and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demon- strates that KMnO4 oxidation is an effective option to remove dimethyl trisulfide from water.Xiaoyan MA Shifei HU Hongyu WANG Jun LI Jing HUANG Yun ZHANG Weigang LU Qingsong LI 2012Frontiers of Environmental Science & Engineering2012,6,2:3
20Endoscopic characteristics in predicting prognosis of biopsy-diagnosed gastric low-grade intraepithelial neoplasia显示文摘Background: Endoscopic biopsy can underestimate gastric malignancies as low-grade intraepithelial neoplasia (LGIN). Definitively diagnosed LGIN would progress. This study aimed to evaluate predictive factors to identify malignancies misdiagnosed as LGIN by biopsy and LGIN at high risk of progression.Methods: The clinical records of patients diagnosed with gastric LGIN by endoscopic biopsy who underwent at least two endoscopies during the first year of follow-up between 2007 and 2017 were retrospectively collected. Three endoscopists reviewed photographs of the initial endoscopy, described lesion characteristics, and made endoscopic diagnoses. Logistic regression was used to analyze predictors to identify malignancies underestimated as LGIN. A receiver operating characteristic curve was used to evaluate the diagnostic accuracy of these predictors. Patient clinical outcomes of follow-up >1 year were collected. Kaplan-Meier estimates with log-rank tests and Cox proportional hazards regression were used to analyze predictors of progression.Results: Overall, 48 of 182 (26.4%) patients were proven to have malignancies. A single lesion, a large lesion size, and marked intestinal metaplasia (IM) were independent predictors of initially misdiagnosed malignancies. The area under the curve of these predictors was 0.871, with a sensitivity of 68.7% and specificity of 92.5%. Twelve of 98 patients (12.2%) progressed during the 33-month median follow-up period. A whitish appearance, irregular margins, marked IM, and histological diagnosis of LGIN more than twice within the first year were predictors for progression.Conclusions: Lesions diagnosed as LGIN by biopsy with marked IM and other predictors above should be prudently treated for high potential to be malignancies or progress. Endoscopic follow-up with repeated biopsies within the first year is recommended.Long Zou Qingwei Jiang Tao Guo Xi Wu Qiang Wang Yunlu Feng Shengyu Zhang Weigang Fang Weixun Zhou Aiming Yang 2022Chinese Medical Journal2022,,1:3
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