Optimal storage temperature and 1-MCP treatment combinations for different marketing times of Korla Xiang pears

Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, but the fruit quality was reduced by early harvesting, and the decreasing storage temperature increased the risk of chilling injury. The objectives of this study were to determine the optimal storage parameters for different storage times and to find ways to preserve the green skin color of pears. Specifically, we analyzed the effects of the ethylene inhibitor, 1-methylcyclopropene （1-MCP）, combined with low temperature on quality and maintenance of the green color of Korla Xiang pears during storage. We found that 1-MCP and/or low temperature reduced the loss of green color at 20℃ after being removed from cold storage. In addition, 1-MCP significantly inhibited the decline of titratable acid and ascorbic acid but had no significant effect on fruit firmness and total soluble solids. Low temperature with or without 1-MCP inhibited the release of ethylene, inhibited the decline in the stalk preservation index, inhibited the increase in decay rate and weight loss rate during storage, and inhibited the increase in the core browning index after 225 days of storage. Different storage temperatures had different effects on the quality of Korla Xiang pears. Despite inhibiting ethylene release, a storage temperature of-1.5℃ increased the respiration rate. Storage at -1.5℃ caused core browning eady during storage due to chilling injury, whereas at 2℃ core browning occurred late during storage due to senescence. In late storage, 1-MCP had no significant effect on the maintenance of Korla Xiang pear quality at 2℃. Based on these results, we determined the optimal combinations of low temperature and 1-MCP treatment to maintain pear quality while avoiding chilling injury. For different marketing times, the optimal conditions for storage until New Year＇s Day （a storage duration of 90 days） are 2℃ or 1-MCP combined with 2℃. For storage until the Spring Festival （a storage duration of 150 days）, the optimal conditions are 0℃ or 1-MCP combined with 0℃, and for storage until May （a storage duration of 225 days）, the best conditions are 1-MCP combined with -1.5℃.

Characterizing urban expansion of Korla City and its spatial-temporal patterns using remote sensing and GIS methods

Cities provide spatial contexts for populations and economic activities. Determining the spatial-temporal patterns of urban expansion is of particular significance for regional sustainable development. To achieve a better understanding of the spatial-temporal patterns of urban expansion of Korla City, we explore the urban expansion characteristics of Korla City over the period 1995-2015 by employing Landsat TM/ETM＋ images of 1995, 2000, 2005, 2010, and 2015. Urban land use types were classified using the supervised classification method in ENVI 4.5. Urban expansion indices, such as expansion area, expansion proportion, expansion speed, expansion intensity, compactness, and fractal dimension, were calculated. The spatial-temporal patterns and evolution process of the urban expansion （e.g., urban gravity center and its direction of movement） were then quantitatively analyzed. The results indicated that, over the past 25 years, the area and proportion of urban land increased substantially with an average annual growth rate of 15.18%. Farmland and unused land were lost greatly due to the urban expansion. This result might be attributable to the rapid population growth and the dramatic economic development in this area. The city extended to the southeast, and the urban gravity center shifted to the southeast as well by about 2118 m. The degree of urban compactness tended to decrease and the fractal dimension index tended to increase, indicating that the spatial pattern of Korla City was becoming loose, complex, and unstable. This study could provide a scientific reference for the studies on urban expansion of oasis cities in arid land.

Transcriptome analysis to identify candidate genes related to chlorogenic acid biosynthesis during development of Korla fragrant pear in Xinjiang

Korla fragrant pear(KFP)with special fragrance is a unique cultivar in Xinjiang,China.In order to explore the biosynthesis molecular mechanism of chlorogenic acid(CGA)in KFP,the samples at different development periods were collected for transcriptome analysis.High performance liquid chromatography analysis showed that CGA contents of KFP at 88,118 and 163 days after full bloom were(20.96±1.84),(12.01±0.91)and(7.16±0.41)mg/100 g,respectively,and decreased with the fruit development.Pears from these typical 3 periods were selected for de novo transcriptome assemble and 68059 unigenes were assembled from 444037960 clean reads.One‘phenylpropanoid biosynthesis’pathway including 57 unigenes,11 PALs,1 PTAL,64CLs,9 C4Hs,25 HCTs and 5 C3’Hs related to CGA biosynthesis was determined.It was found that the expression levels of 11 differentially expressed genes including 1 PAL,2 C4Hs,34CLs and 5 HCTs were consistent with the change of CGA content.Quantitative polymerase chain reaction analysis further showed that 8 unigenes involved in CGA biosynthesis were consistent with the RNA-seq data.These findings will provide a comprehensive understanding and valuable information on the genetic engineering and molecular breeding in KFP.

Land degradation sensitivity assessment and convergence analysis in Korla of Xinjiang, China

Land degradation has a major impact on environmental and socio-economic sustainability. Scientific methods are necessary to monitor the risk of land degradation. In this study, the environmental sensitive area index(ESAI) was utilized to assess land degradation sensitivity and convergence analysis in Korla, a typical oasis city in Xinjiang of China, which is located on the northeast border of the Tarim Basin. A total of 18 indicators depicting soil, climate, vegetation, and management qualities were used to illustrate spatial-temporal patterns of land degradation sensitivity from 1994 to 2018. We investigated the causes of spatial convergence and divergence based on the Ordinary Least Squares(OLS) and Geographically Weighted Regression(GWR) models. The results show that the branch of the Tianshan Mountains and oasis plain had a low sensitivity to land degradation, while the Tarim Basin had a high risk of land degradation. More than two-thirds of the study area can be categorized as "critical" sensitivity classes. The largest percentage(32.6%) of fragile classes was observed for 2006. There was no significant change in insensitive or low-sensitivity areas, which accounted for less than 0.4% of the entire observation period. The ESAI of the four time periods(1994–1998, 1998–2006, 2006–2010, and 2010–2018) formed a series of convergence patterns. The convergence patterns of 1994–1998 and 1998–2006 can be explained by the government's efforts to "Returning Farmland to Forests" and other governance projects. In 2006–2010, the construction of afforested work intensified, but industrial development and human activities affected the convergence pattern. The pattern of convergence in most regions between 2010 and 2018 can be attributed to the government's implementation of a series of key ecological protection projects, which led to a decrease in sensitivity to land degradation. The results of this study altogether suggest that the ESAI convergence analysis is an effective early warning method for land degradation sensitivity.

Response of Leaf Tissue Structure to Exogenous ABA in Korla Fragrant Pear

To study the effects of different concentrations of Abscisic Acid(ABA) on leaf tissue structure of Korla fragrant pear and lay the foundation for the cultivation and regulation of Korla fragrant pear. Using the paraffin section method, the leaf thickness, the epidermis thickness, the palisade tissue thickness and the sponge tissue thickness were measured; palisade spongy ratio, Cell Tightness(CT) and Cell Looseness(CL) were examined after treatments with exogenous ABA. Leaf thickness, leaf palisade spongy ratio and palisade tissue thickness increased significantly after exogenous ABA treatment compared with CK, while the effect on leaf epidermis was not obvious. The leaf thickness and palisade tissue thickness increased evidently after 70 mg · LABA treatment by 24.89% and 41.10%, respectively. The tissue structures of leaves were more compact, while CL was lower after 70 and 90 mg · LABA treatments. The effects of different concentrations of exogenous ABA could increase the leaf thickness, palisade tissue thickness of Korla fragrant pear and CT, reduced the thickness of spongy tissue and CL. Among those concentrations of exogenous ABA, the effect of spraying 70 mg · Lexogenous ABA was suitable for improving cold resistance of Korla fragrant pear.

Industrialization Development of Korla Fragrant Pear in Bayingolin Mongol Autonomous Prefecture,China

Based on the introduction of the natural and geographical conditions in Bayingolin Mongol Autonomous Prefecture in Xinjiang(Bazhou),development status of Korla Fragrant Pear is introduced from the two aspects of the production status and the storage and processing status of Korla Fragrant Pear.Among them,production status of Korla Fragrant Pear is analyzed from the aspects of the rapid growth of planting area and the stable growth of output.And the storage and processing status of Korla Fragrant Pear is introduced from the aspects of the development status of the storage industry the development status of processing industry,and the status of domestic and foreign marketing.Problems in the industrialization development of Korla Fragrant Pear in Bazhou are analyzed,such as the weak protection of brand and lack of external propaganda,the imperfect benefit affiliating mechanism between leading enterprises and peasant households,and the marketing network of Korla Fragrant Pear and single mode of marketing.Countermeasures for the acceleration of the industrialization development of Korla Fragrant Pear in Bazhou are put forward,such as making great effort at publicity,brand establishment and counterfeit prevention,cultivating leading enterprises,reducing market risk,implementing industrialization development,adopting various marketing forms and actively developing domestic and international markets.

Model for estimating the weight-loss ratio of damaged Korla fragrant pears

To predict the weight-loss ratio of Korla fragrant pears effectively,improve commodity value and study the variation laws of the weight-loss ratio of damaged fragrant pears during storage,this study predicted the weight-loss ratio of fragrant pears by utilizing the generalized regression neural network(GRNN),support vector regression(SVR),partial least squares regression(PLSR)and error back propagation neural network(BPNN).The prediction performances of GRNN,SVR,PLSR and BPNN models were compared comprehensively,and the optimal model was determined.In addition,the optimal prediction model was verified.The results show that weight-loss ratio of fragrant pears increases gradually with the extension of storage time.During storage,the weight-loss ratio of fragrant pears is positively related to the degree of damage.The trained GRNN,SVR,PLSR and BPNN models can be used to predict the weight-loss ratio of fragrant pears.The BPNN model is the most accurate in predicting the weight-loss ratio of damaged fragrant pears(R^(2)=0.9929;RMSE=0.2138).It has also been proved to have good predictive effect in production practice(R^(2)=0.9377,RMSE=0.7138).The research findings can provide references to predict the delivery quality and time of delivery of Korla fragrant pears.

梨火疫病抗性评价体系的建立及其种质资源抗性鉴定

【目的】利用梨幼果建立梨火疫病(Erwinia amylovora)抗性资源评价体系,筛选出对梨火疫病具有抗性的材料,为抗病育种提供技术支撑。【方法】以36个梨品种和41个库尔勒香梨杂交后代为材料,利用人工接种的方式对幼果期、膨大期和成熟期的果实进行接种试验,并根据接种后致病力的强弱,制定梨品种(种质)的抗性分级指标,综合评价77份种质资源的抗病水平。【结果】与梨果实膨大期和成熟期相比,接种幼果期果实更能准确评估梨品种(种质)的抗性水平;在接种24 h后,梨幼果开始显症;77个品种(种质)对梨火疫病的抗性水平差异显著,高感品种(种质)13个,感病品种(种质)11个,中感品种(种质)27个,抗病品种(种质)26个;供试品种(种质)对梨火疫病的抗性不高,其中只有33.77%的品种(种质)表现抗病性,66.23%的品种(种质)不同程度感病。【结论】本研究建立以梨果实的幼果期为接种时期,在接种24 h时开始观察发病情况的梨火疫病抗性资源评价体系;从供试品种(种质)筛选出的26份材料达到抗性水平,为培育新的抗性品种提供参考。

乡村振兴战略背景下库尔勒休闲露营地建设路径与模式

基于乡村振兴战略的视角,结合目前库尔勒市的休闲露营地经营现状,通过对经营者与消费者有关休闲露营地区位条件、基础设施、自然环境、服务质量、政策支持等方面的问卷调查,分析库尔勒地区休闲露营地建设的条件与存在的问题,提出基于当地资源与需求的休闲露营地建设路径与模式,即露营地+生态园模式、露营地+农村+农户模式、露营地+研学模式,旨在推动农村旅游业的发展,促进库尔勒地区乡村经济社会的发展。

库尔勒香梨大疆T50无人机授粉参数优选与田间验证

为了提高库尔勒香梨无人机授粉作业的精确性,选用大疆T50无人机,采用三因素(作业速度、作业高度、667 m^(2)喷施量)三水平的正交试验,比较雾滴覆盖率、雾滴密度及雾滴沉积量的分布效果,筛选作业参数并进行了田间授粉效果的验证。结果表明:在环境风速不超过1.5 m/s的条件下,大疆T50无人机对纺锤形库尔勒香梨授粉的最佳作业参数为作业速度4 m/s、作业高度距离树顶4.5 m、667 m^(2)喷施量4L;田间授粉的花序坐果率为75.56%,花朵坐果率为32.87%。影响库尔勒香梨树冠上层雾滴效果的主要因素依次为667 m^(2)喷施量、作业高度、作业速度,影响树冠中层和下层雾滴效果的主要因素依次为667 m^(2)喷施量、作业速度、作业高度。

库尔勒香梨园土壤肥力空间变异特征与综合评价分析

为研究库尔勒香梨园土壤pH、盐分、速效养分以及微量元素空间分布特征,掌握香梨园综合肥力水平,以库尔勒市香梨种植区为研究区,选取具有代表性的50个库尔勒香梨园进行样点布设与土样采集。运用经典统计学和地统计学方法研究香梨园表层(0~40 cm)土壤养分指标和微量元素指标的空间变异性,探究香梨园土壤肥力状况。经典统计分析表明:pH的变异系数为0.02属于弱变异,电导率的变异系数为1.03表现为强变异,有机质、碱解氮、速效磷、速效钾、有效锰、有效铜、有效锌和有效铁的变异系数分别为0.37、0.53、0.99、0.59、0.45、0.25、0.24和0.48,为中等变异程度,研究区土壤综合肥力指数IFI值在0.37~0.80之间,平均值为0.58;地统计分析表明:土壤有机质、碱解氮和速效钾的块金系数大于75%,空间自相关性较弱;pH、电导率、速效磷、有效锰、有效铜、有效锌和有效铁的块金系数在25%~75%之间,这些指标具有中等强度的空间自相关性;库尔勒香梨园Ⅰ(优)、Ⅱ(良好)、Ⅲ(中等)、Ⅳ(较差)和Ⅴ(差)类土壤占比分别为2.72%、10.54%、61.80%、24.87%、和2.77%,土壤综合肥力在空间上呈现斑块状,肥力较好的Ⅰ级在北部零星分布、Ⅱ级斑块状分布在北部及西部,Ⅲ级主要分布在北部以及南部,肥力较差的Ⅳ、Ⅴ级主要集中在中部。总体上,库尔勒市香梨园土壤肥力为中等水平,土壤属性空间异质性比较强,其中有效锰、有效铁是制约土壤肥力的主要限制因子,果园有必要进行差异化管理,并应重视补充锰、铁微量元素肥,此外中部地区还要着重补充氮肥、磷肥和有机肥。

不同保鲜剂处理对鲜切库尔勒香梨品质的影响

为探索不同保鲜剂处理对鲜切库尔勒香梨的保鲜效果,以新疆库尔勒香梨为试材,选用不同保鲜剂(褪黑素、氯化钠、氯化钙、水杨酸)处理,通过测定其理化指标及菌落总数,分析货架期鲜切梨的保鲜效果。结果表明:4种保鲜剂对鲜切梨均具有较好保鲜效果。与对照组相比,4种保鲜剂均能够有效抑制多酚氧化酶活性,减缓鲜切梨褐变,维持鲜切梨可溶性固形物、总酸、总糖、维生素C含量。在所有处理组中,褪黑素处理组和水杨酸处理组可较好地维持鲜切梨的质量和色泽,显著抑制微生物生长,减缓品质下降,能够有效延长鲜切库尔勒香梨的货架期。

基于多光谱图像角度融合测定库尔勒香梨理化指标

基于多光谱图像角度融合,提出了一种库尔勒香梨快速无损检测的方法。以库尔勒香梨为研究对象,应用多光谱成像采集系统,以10°为间隔,获取了相对方位角为10°~90°内的多光谱图像。使用ENVI5.1软件进行多光谱图像角度融合并提取感兴趣区域(ROI),获得多光谱数据。对光谱反射率、波段和相对方位角进行了皮尔逊相关性分析,发现波段和相对方位角都对光谱反射率呈极显著相关性,且相对方位角相关系数为0.1大于波段相关系数0.053,有必要在建模过程中加入相对方位角因素。采用标准正态变量变换(SNV)、均值中心化变换(MC)、卷积平滑处理(S_G)和归一化处理(Nor)等预处理方法,选用偏最小二乘回归(PLSR)建立全波段检测模型,通过校正集相关系数(R_(c))、预测集相关系数(R_(p))、校正集均方根误差(RMSEC)和预测集均方根误差(RMSEP)对模型的效果进行评价,对比探究特征角度下和角度融合下库尔勒香梨关键指标的模型检测效果。结果表明:采用角度融合处理后,所建立的PLSR和SVM模型预测效果都有显著提升。预测库尔勒香梨含水率最优模型为采用角度融合的偏最小二乘回归模型(AF-PLSR),其R_(c)为0.936, RMSEC为0.298,R_(p)为0.901, RMSEP为0.285;预测库尔勒香梨硬度和糖度的最优模型为以角度融合的支持向量机模型(AF-SVM),R_(c)分别为0.894、 0.905, RMSEC为0.527、 0.376;R_(p)为0.830、 0.901, RMSEP为0.532、 0.379。角度融合将不同角度下的光谱数据结合在一起,获得了比单一角度更加丰富的信息,得到了更加完善的光谱。所建立的检测模型精度更高。结果证明:基于多光谱图像角度融合技术预测库尔勒香梨的含水率、硬度和糖度是可行的。为提高多光谱无损检测精度和高光谱无损检测精度提供了一种新的思路。

库尔勒香梨芽变材料物候期及坐果特性观测

【目的】观测研究库尔勒香梨芽变材料的物候期及坐果特性,为提升库尔勒香梨品质提供参考依据。【方法】以库尔勒香梨和库尔勒香梨芽变材料为研究对象,设置芽变材料无人工授粉组、普通库尔勒香梨人工授粉组和普通库尔勒香梨无人工授粉组,且3个处理组均不喷施促进萼片脱落的药剂,研究3个处理组的物候期、坐果率及脱萼率。【结果】库尔勒香梨芽变材料与普通库尔勒香梨的物候期高度重合,相差不超过2 d;芽变材料无人工授粉组坐果率与脱萼率>普通库尔勒香梨人工授粉组坐果率与脱萼率>普通库尔勒香梨无人工授粉组坐果率与脱萼率,3个处理组之间均存在极显著差异。【结论】芽变材料与普通库尔勒香梨的物候期基本一致,现有库尔勒香梨种植区的管理方式无需改变即可直接利用该材料进行嫁接;芽变材料的坐果率与脱萼率都显著高于普通库尔勒香梨,在栽培过程中可以有效减少使用化学药剂,降低成本且提高果实品质。

氮输入对库尔勒香梨园土壤细菌群落的影响

【目的】为梨园的合理施肥及可持续健康发展提供参考。【方法】以库尔勒香梨园0~20 cm土层土壤样品为材料,通过分析细菌群落物种组成的相对丰度、α多样性指数,研究了0、150、300、450 kg/hm^(2)共4个施氮水平对库尔勒香梨园土壤细菌群落的影响。【结果】电导率、碳氮比、全氮含量及硝态氮含量对门水平细菌群落的影响达显著水平,硝态氮含量、铵态氮含量、碱解氮含量、全碳含量、碳氮比及电导率对属水平细菌群落的影响达显著水平。施用氮肥后,放线菌门Actinobacteria、类诺卡氏属Nocardioides的相对丰度有所下降,且与土壤氮养分含量以及pH值显著或极显著负相关;施用氮肥后,厚壁菌门Firmicutes、异常球菌-栖热菌门Deinococcus-Thermus、己科河菌门Rokubacteria、A4b、动孢菌属Kineosporia的相对丰度有所增加,芽孢杆菌属Bacillus、盐单胞菌属Halomonas在膨果期的相对丰度在施用氮肥后有所增加,其中己科河菌门的相对丰度与土壤碳氮养分含量以及pH值有显著或极显著相关性,A4b的相对丰度与有机碳含量显著或极显著正相关,动孢菌属的相对丰度与土壤氮养分含量以及pH值显著或极显著正相关,芽孢杆菌属的相对丰度与全氮含量、铵态氮含量显著正相关;绿弯菌门Chloroflexi以及在膨果期的酸杆菌门Acidobacteria、考克氏菌属Kocuria、游球菌属Planococcus的相对丰度随施氮量的增加呈先增加、后降低的趋势,绿弯菌门、酸杆菌门的相对丰度与有机碳含量显著或极显著正相关。在膨果期,随施氮量的增加,细菌群落的Pielou均匀度指数、Shannon指数均表现为先增加、后降低的趋势,300 kg/hm^(2)处理下最高;各处理Chao1指数和Observed species指数均表现为在成熟期最高。相关性分析结果表明细菌群落多样性主要受氮组分含量、有机碳含量以及pH值的影响。【结论】添加氮肥可以影响土壤细菌群落的组成及其多样性,因此适当控制氮素的供给以及调节土壤碳氮比、pH值等,可改善土壤微生物群落结构,维持土壤品质的稳定和微生物区系的健康。

基于移动窗口法的库尔勒市土地利用景观格局特征分析

绿洲城市是干旱区人类生产和生活的中心,作为绿洲城市,库尔勒市人地关系同样敏感。了解土地利用景观格局的时空演变对于改善该区域的人地关系与生态安全、促进高质量发展具有重要意义。运用景观生态学原理,根据各类景观参数从景观水平与类别上分析库尔勒市土地利用景观格局并用地理探测器模型来分析驱动力。结果表明,1)未利用地依旧为景观的基质。2)景观类型的转移特征在景观面积与类型间的转换上有较显著的时空变化。3)PD、NP、DIV、SHDI和SHEI逐渐增加;CONTAG减少,城郊的破碎化程度均呈持续增大趋势,人类活动影响不断增强,城市化水平提高,库尔勒市处于高速发展时期。4)影响库尔勒市土地覆被/土地利用时空变化分异的主导影响因子是归一化植被指数(NDVI),其贡献率最高;在交互因子探测结果中,NDVI与降水量与气温共同作用时,呈现双因子增强,解释力最大。气温年平均变化与降水量在总体上处于波动上升的阶段,这对提升绿地林地面积以及进行进一步的生态修复都产生了积极的影响。景观破碎化格局的研究利于领会大城市快速成长阶段的景观格局变化规律,为城市生境保护,生态功能修复提供基础。

库尔勒香梨大果芽变的鉴定与评价

为鉴定和评价库尔勒香梨大果芽变的性状,为生产栽培和遗传育种提供理论依据,在2020—2021年对库尔勒香梨(对照)及其大果芽变的植物学形态、生物学特性、品质特性进行比较分析。结果表明,大果芽变果实呈倒卵形,库尔勒香梨呈纺锤形;大果芽变的叶片保卫细胞宽度和果肉细胞长度均显著增大;在果实动态发育过程中,大果芽变的单果重及果实含水率均显著高于库尔勒香梨,在果实成熟期,与库尔勒香梨相比,大果芽变果实的可溶性糖含量及糖酸比分别显著提高78.39%和84.54%,石细胞含量显著降低33.33%。经表型性状和品质特性分析,判定大果芽变为库尔勒香梨的优良芽变,可作为品种改良及新品种选育的亲本材料。

基于花序坐果数和果实直感筛选库尔勒香梨适宜的授粉品种

‘库尔勒香梨’属于异花授粉的梨品种。在主产区立地田间下筛选合适的授粉品种是实现提质增效的重要技术措施。试验选择13个梨品种作为父本对‘库尔勒香梨’进行授粉,自然授粉作为对照,分别于授粉后20 d和80 d对花序坐果数进行调查,待果实成熟后将授粉果实的部分指标和种子特性进行测定和比较分析,采用相关性分析和主成分分析对授粉果实的12项指标进行果实性状综合评价并计算综合得分,为‘库尔勒香梨’筛选高效授粉品种提供参考。结果表明:不同授粉组合中,花序坐果数较对照显著提高,在单果质量、偏斜指数、果实硬度、可溶性固形物含量、石细胞团含量、种子数、鲜籽质量和干籽质量方面果实直感效应明显,但在果形指数、可食部分大小(心果比)和饱籽数果实直感效应不完全明显。部分果实指标间存在着显著或极显著的相关性。通过主成分分析所提取的4个主成分累计方差贡献率达89.298%,包含了果实指标的大部分信息,综合得分结果显示‘南果梨’‘园黄’‘寒红’‘砀山酥梨’和‘新妃’5个梨品种对‘库尔勒香梨’授粉效果较好。

库尔勒土壤模拟液中木质素磺酸钙对纯铜接地材料的缓蚀及吸附行为研究

为了探究库尔勒土壤模拟液中添加木质素磺酸钙,对纯铜接地材料的缓蚀效率及其在纯铜接地材料表面的吸附行为,采用动电位极化曲线和电化学阻抗谱研究了库尔勒土壤模拟液中木质素磺酸钙(CLS)对纯铜接地材料腐蚀行为的影响。结果表明,当CLS浓度在(2.27~9.08)×10^(-4) mol/L范围增加时对Cu的缓蚀效率逐渐增大,表明添加CLS可有效抑制Cu的腐蚀反应过程,该土壤模拟溶液体系中CLS属于一种阳极缓蚀剂。Mott-schottky曲线分析结果表明,土壤模拟液中Cu表面形成的膜具有P型半导体膜性质,且CLS浓度在(2.27~9.08)×10^(-4) mol/L范围增加时NA浓度降低,Cu表面形成的半导体保护膜具有更佳的保护性。采用3种等温吸附曲线的拟合结果表明,CLS缓蚀剂分子在Cu表面的吸附更倾向Langmuir模型,在2.27×10^(-4)~9.08×10^(-4) mol/L的浓度范围内CLS在Cu表面的ΔGm值介于-37.00~-20.00 kJ/mol之间,表明CLS在Cu表面是由物理吸附和化学吸附共同控制的混合吸附过程。

南疆最大城市2018―2022年环境空气质量变化特征分析

基于2018—2022年南疆最大城市(库尔勒市)六项大气污染物监测数据(PM_(2.5)、PM_(10)、SO_(2)、NO_(2)、CO和O_(3)),分析了库尔勒市近五年环境空气质量变化特征及其污染物浓度水平.结果表明:2018―2022年库尔勒市空气质量总体逐年向好,空气质量优良天数由2018年的223 d增长到2022年的250 d,增加了27 d;达标率由2018年的62.5%增长到2022年的68.5%,增长了6.0%,重度及以上污染天数降低了23.3%.环境空气质量指数(Air Quality Index,AQI)降低了5.4%,五年的AQI值均高于100,空气质量处于轻度污染水平.常规六项污染物中SO_(2)和CO的浓度呈逐年下降趋势,NO_(2)浓度年际变化不明显,但SO_(2)、NO_(2)、CO的年均值和季节均值均优于国家环境空气污染物浓度限值一级标准.O_(3)的年均值优于国家环境空气污染物浓度限值一级标准,但O_(3)四季的浓度年际变化均呈上升趋势,且2021年和2022年夏季和秋季浓度值均高于100μg·m_(-3).2018—2022年库尔勒市PM_(2.5)呈下降趋势,但PM10变化不明显,PM_(10)各年浓度值均大于国家环境空气污染物浓度限值二级标准(70μg·m^(-3))2倍以上,说明库尔勒市近几年PM_(10)污染非常严重.此外,每年1月PM_(2.5)/PM_(10)最高、3月PM_(2.5)/PM_(10)最低,说明1月至3月粒径大于2.5μm的颗粒物浓度逐渐增加,这主要是因为库尔勒市每年春季受沙尘天气的影响.