首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 796 毫秒
1.
冷激黄瓜贮藏品质及冷激过程传热特性分析   总被引:3,自引:1,他引:2  
为研究冷激处理对黄瓜保鲜效果的影响及冷激过程中黄瓜内部组织传热机理,建立了黄瓜冷激过程的传热数学模型,并以0℃的冰水混合物为冷激介质,对处理时间分别为20、40、60 min黄瓜的保鲜效果进行了对比试验研究。结果表明,黄瓜保鲜效果差异不仅与冷激处理时组织的最低温度有关,还与最低温度持续的时间有关。冷激处理40 min能够有效抑制黄瓜硬度、可溶性固形物含量的下降,减缓失重率的上升,保持较高的过氧化物酶活性。所建的传热模型能够准确预测冷激处理过程中黄瓜不同深度位置处的组织温度变化。冷激传热模型及相关结论可为黄瓜采后冷激处理工艺提供理论及实践指导。  相似文献   

2.
双温冷激处理对黄瓜品质和生理的影响及传热特性分析   总被引:1,自引:1,他引:0  
为探究果蔬冷激过程中传热特性对保鲜效果的影响,分别对黄瓜进行常规冷激处理(0℃冰水混合物处理42min)及双温冷激处理(0℃冰水混合物处理14min后放到6℃冷水中处理14min,最后返回0℃冰水混合物处理14min)。测定了处理过程中黄瓜组织温度分布及贮藏期间失重率、硬度、过氧化物酶(peroxidase,POD)活性等品质和生理变化,分析了黄瓜贮藏品质与传热特性的内在关系。结果表明:双温冷激处理在延缓细胞膜降解、提高POD活性方面显著优于常规冷激处理(P<0.05),在10℃冷库贮藏15d后,其相对电导率、POD活性分别是常规冷激组的92%及1.24倍;双温冷激黄瓜内部组织温度梯度在处理第29min时的阶跃式升高,以及从处理第29min到处理结束过程中,黄瓜内部组织温度梯度高于常规冷激黄瓜,或许是双温冷激处理黄瓜保鲜效果较好的内在因素。所得结论可为双温冷激处理的应用提供参考。  相似文献   

3.
果蔬热处理传热过程的数值模拟及验证   总被引:3,自引:3,他引:0  
为了研究果蔬采后热处理过程的传热机理,建立了柱状与球状果蔬热处理的普适传热模型,对模型进行了数值模拟及试验验证。结果表明:所建模型能够准确预测多种边界条件下柱状与球状果蔬热处理时的组织温度变化及动态响应,柱状及球状果蔬的模型预测值与实测值的平均相对误差及均方根误差均低于5%。热水浸泡法与热空气法的对比试验表明:达到相同的热处理效果,伊丽莎白香瓜热水浸泡法的处理时间仅为热空气法的35%~50%;热水浸泡法中香瓜果实的表面换热系数为190~250 W/(m2·℃),而在热空气法中仅为10~30 W/(m2·℃  相似文献   

4.
相对湿度作为干燥介质的重要参数,对干燥热质传质过程和干燥品质具有显著影响。但由于相对湿度对干燥过程的影响机理及优化调控机制尚不明确,导致相对湿度的调控方式多依靠经验,造成干燥效率低、品质差、能耗高等问题。对于传质过程,降低相对湿度能够增大对流传质系数,加快物料表面水分蒸发;而对于传热过程,升高相对湿度能够增大对流传热系数,加快物料升温速率。相对湿度较高时,物料升温速率快,内部水分迁移量增大,但表面水分蒸发量较小;而当相对湿度较低时,物料升温速率较慢,内部水分迁移量较小,但表面水分蒸发量较大。相对传热和传质过程的影响此消彼长,互相耦合。高相对湿度主要体现为对传热过程的影响,低相对湿度主要体现为对传质过程的影响。高相对湿度能够抑制物料表面的结壳,并能够提高复水性,降低收缩率。阶段降湿及多阶段降湿干燥方式下物料表面形成和保持了蜂窝状多孔结构,能够提高干燥效率和品质。基于监测物料温度的相对湿度调控方式被验证为较忧的相对湿度控制方式。阶段降湿干燥方式适用性的实质为:干燥过程中所体现出的对流传热热阻和内部导热热阻的相对大小,及对流传质阻力和内部传质阻力的相对大小,不同干燥条件和物料种类、厚度会影响以上传热传质阻力的大小,从而呈现出不同适应性的结果。当阶段降湿干燥过程中传热毕渥数>1且传热毕渥数>0.1时,说明阶段降湿干燥过程适用于此物料的干燥。该文综合论述了相对湿度对果蔬热风干燥过程中热质传递及干燥品质的影响,优化调控策略及适用性范围4个方面内容,明确了果蔬热风干燥过程中相对湿度的影响机理,为相对湿度的优化调控提供理论依据和技术支持。  相似文献   

5.
采用溶液培养方法,研究了氮素形态及水平对黄瓜干物质积累、膨压及光合速率的影响。结果表明,同一氮素水平时,NO3--N处理黄瓜干物质重量、叶片面积、叶片含水量、水势、膨压等均高于NH4+-N处理。低水平NH4+-N(5mmol/L)对黄瓜光合速率影响不大,甚至高于同水平NO3--N处理的,叶片面积稍有减小;高水平NH4+-N不仅显著抑制黄瓜干物质的积累,叶片面积仅是同水平NO3--N处理的12.7%,最小光合速率(Pn)为CO2 1.6mol/(m2·s),仅为同水平NO3--N处理的10%左右。NH4+-N处理引起黄瓜叶片面积的减小与叶片膨压降低相关性较大,相关系数为0.98;膨压与叶片水势直接相关,而渗透势对此影响不大。高水平NO3--N对黄瓜产生了渗透胁迫,抑制黄瓜生长,表现在渗透调节物质的大量积累。不同黄瓜品种对氮素形态及水平响应差异较大,所有处理中新泰密刺长势均好于吉尼罗。低水平的NH4+-N对黄瓜干物质的积累影响不大,高水平则明显抑制其生长。说明高浓度铵态氮对植物产生了毒害,而高浓度的硝态氮则是渗透胁迫。  相似文献   

6.
间歇热处理过程中,温度的变化会激发果实内部生理变化,研究不同处理时间下果实组织温度分布及变化速率对揭示热处理保鲜机理具有重要意义。该研究以樱桃为处理对象,采用50℃热水,20℃冷水交替喷淋的处理方式,同时选择20、100、180 s作为不同的间歇处理时间,果实的贮藏品质作为评价指标。建立单个果实的非稳态传热模型,对间歇热处理时樱桃组织的传热规律及动态响应过程进行数值分析。结果表明,间歇喷淋热处理可以提高樱桃贮藏品质,且不同的热处理时间对果实的温度场及品质的影响有显著差异(P<0.05)。优化后的参数为:间歇处理时间180s,50℃喷淋处理3次,总热处理时间为540 s。在此条件下樱桃与处理介质之间的热量传递最充分,单个果实半径1/2处温度平均值为27.71℃,中心温度平均值为30.85℃。优化间歇热处理组的腐烂率比未做任何处理的对照组低53.4%,能较好维持果实硬度。根据传热模型及相关结论,建议间歇处理时间应大于温度变化速率峰值的出现时间。研究结果可为樱桃采后保鲜技术提供理论参考。  相似文献   

7.
电导率对温室黄瓜叶面积和干物质生产影响的动态模拟   总被引:2,自引:2,他引:0  
电导率是温室营养液管理的重要参数.为定量研究不同电导率对温室黄瓜光合与干物质生产的影响,该文以温室黄瓜为试验材料,于2009年10月至2010年7月进行了不同电导率的营养液栽培的试验,定量分析了电导率对温室黄瓜叶面积、光合速率和干物质生产的影响,构建了以辐热积为尺度的叶面积指数、最大光合速率和干物质生产模型,并用独立的试验数据对模型进行了检验.结果表明:模型对温室黄瓜叶面积、最大光合速率和干物质产量的模拟值与实测值之间的决定系数分别为0.89、0.93和0.94,回归估计标准误差分别为0.21m2/m2、1.52 μmol/(m2.s)和36.77 kg/hm2,预测相对误差分别为4.5%、11%和9.2%.该研究建立的模型可以为温室黄瓜的营养液管理和决策提供依据.  相似文献   

8.
不同营养液浓度对温室黄瓜叶片光合特性的影响   总被引:3,自引:1,他引:2  
为了探究不同电导率(electrical conductivity,EC)的营养液对温室黄瓜叶片光合特性的影响,该文于2009年10月至2010年7月在江苏大学Venlo型温室中进行试验,采用4种EC值的营养液浇灌黄瓜,对4种EC值条件下温室黄瓜叶片的光合速率、叶绿素荧光、叶绿素含量及产量进行了测定,并对EC对黄瓜叶片叶绿素仪读数、光合速率和最大电子传递速率的影响及其之间的关系进行了分析。研究结果表明,营养液的电导率值对温室黄瓜下部叶片的叶绿素仪读数值、最大光合速率、光能初始利用率和电子传递速率有较大的影响,中部叶、上部叶片的叶绿素仪读数值、最大光合速率、光能初始利用率、电子传递速率和产量在不同处理间无论是秋冬茬还是早春茬均表现为:营养液的电导率为2.5 dS/m和营养液的电导率为2.2 dS/m差异不显著,但显著大于营养液的电导率为1.5 dS/m和营养液的电导率为0.036 dS/m;构建了最大光合速率与叶片叶绿素仪读数值、光能初始利用率与叶片叶绿素仪读数值的关系模型;光合速率与电子传递速率之间呈幂指数函数关系。该研究为通过叶片光合速率进行营养液管理提供了理论依据。  相似文献   

9.
基于多参数耦合的蓄冷温控箱冷板对流换热参数优化   总被引:2,自引:2,他引:0  
蓄冷温控箱利用低温相变材料储存冷量,通过缓慢释放调节并保持箱内温度,目前仍存在冷量释放速率无法控制、剩余冷量预测难等问题,而蓄冷板表面对流换热系数直接影响冷量的释放速率。针对以上问题,搭建了蓄冷板表面对流换热系数测量试验平台,研究不同环境及蓄冷板参数对表面对流换热系数的影响。采用二次回归正交试验设计方案,探究了蓄冷区进口空气流速、进口空气温度、蓄冷板传热面积以及蓄冷板间距对表面对流换热系数的影响,并对结果进行分析,建立了表面对流换热系数二阶预测模型,获得影响表面对流换热系数大小较显著的因素及较优的参数组合。试验结果表明:各因素间存在明显交互作用,进口空气温度和蓄冷板传热面积的交互效应最大;通过响应曲面法建立的表面对流换热系数预测模型,得到最优参数组合为:进口空气流速4 m/s,进口空气温度25 ℃,蓄冷板传热面积0.455 m2,蓄冷板间距0.04 m,R2值为0.927 4,变异系数CV为5.78%。回归模型计算结果与试验结果吻合,最大误差为3.58%,平均相对误差为2.69%,表明该模型可以快速、准确地预测不同条件下的蓄冷板表面对流换热系数。试验结果为蓄冷温控箱冷量释放速率精准调控及剩余冷量预测提供参考。  相似文献   

10.
研究延长通风时间 (4h/d)并增施CO2 对温室黄瓜光合作用的影响结果表明 ,与对照相比 ,延长通风时间使通风时段内平均CO2 浓度升高 4 3 80 μL/L ,平均温度和湿度分别降低 2 4 0℃和 35 0Pa ,黄瓜叶片露时约缩短 2 5h/d ;延长通风时间与增施CO2 使黄瓜平均光合速率分别提高 1 6 3μmol/m2 ·s和 3 33μmol/m2 ·s,促进光合产物积累。  相似文献   

11.
【目的】以富士(Fuji)、 秦冠(Qinguan)嫁接在平邑甜茶(Malus hupehensis Rehd.)上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水(ZZ)、 低氮正常水(DZ)、 正常氮干旱(ZG)、 低氮干旱(DG)。氮素和水分均设置两个水平,分别为正常氮(6 mmol/L NO-3-N)、 低氮(0.3 mmol/LNO-3-N)、 正常供水(保持盆中砂子相对含水量为饱和含水量的80%~85%)、 干旱处理(保持盆中砂子相对含水量为饱和含水量的60%~65%)。【结果】富士和秦冠的生物量(茎和叶)、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG),并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG); 氮、 钾元素含量在植株各部位的分布顺序依次是叶>根>茎,磷元素则是根>叶>茎;光合氮素利用效率(PNUE)和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水(DZ)处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱(DG)处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。  相似文献   

12.
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.  相似文献   

13.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

14.
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.  相似文献   

15.
Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.  相似文献   

16.
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.  相似文献   

17.
Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.  相似文献   

18.
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.  相似文献   

19.
Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria (Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation. Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured as transpiration and diffusive resistance, when these trees were cultivated without water restrictions.  相似文献   

20.
Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号