Sapflow characteristics of Kandelia obovata and their controlling factors in Zhangjiang estuary,China

利用Granier热消散式探针法对福建漳江口国家级红树林自然保护区内红树植物秋茄的树干茎流密度(SFD)进行1年(2010年10月至2011年10月)的连续监测.结果表明:季节和树干径级对秋茄树干茎流密度均有显著影响.在夏季,胸径(DBH)为8~10 cm时秋茄树干最外层2 cm处的SFD达到最大,为38.21 g·m~(-2)·s~(-1),这与其他红树物种以及湿地乔木物种的茎流密度相当.不同径级(小、中、大径级分别为2~4、4~8、8~10 cm)秋茄每日整树蒸腾量(即水分日利用量)也呈现明显的季节变化,从冬季到夏季的波动值分别为0.14~0.19、0.94~1.45、1.96~3.43 kg·d~(-1).通过整合各个径级秋茄树的日蒸腾量推算得到秋茄林的日蒸腾量,再全年累加计算得到秋茄林年总蒸腾量为100.38 mm,不到当地年降水量的6%.主要环境因子对秋茄林蒸腾速率(E_s)均有极显著影响(P<0.001),其中,光合有效辐射(PAR)和饱和水汽压差(VPD)是E_s最主要的驱动因子,解释了E_s60%~92%的季节变异,且夏季秋茄E_s对PAR和VPD的依赖性大于冬季.秋茄E_s与环境因子之间存在明显的时滞现象,需要在解释秋茄林E_s季节变异时加以考虑.In this study,the Grainer's thermal dissipation probe method was applied to monitor sap flux density( SFD) of a mangrove species Kandelia obovata over a period of one year( 2010-10—2011-10) in Zhangjiangkou Mangrove National Nature Reserve,Fujian,China. The results showed that both season and diameter class exerted significant effects on the SFD of K. obovata trees. In summer,when the diameter at breast height( DBH) reached 8-10 cm,the highest SFD was found at a depth of 2 cm with a value of 38.21 g·m~(-2)·s-1,which was comparable with those for other mangrove tree species and forested wetland tree species. The mean whole tree transpiration( i. e.daily water use) of all stem size classes demonstrated large changes from winter to summer,increased from 0.14 to 0.19 kg·d~(-1)in small trees( S,DBH = 2-4 cm),from 0.94 to 1.45 kg·d~(-1)in medium trees( M,DBH = 4-8 cm) and from 1.96 to 3.43 kg·d~(-1)in large ones( L,DBH = 8-10 cm). The daily transpiration of K. obovata stand was calculated by summing all size classes,which was then summed up for entire year to estimate annual transpiration of entire K. obovata forest,which was about 100. 38 mm,less than 6% of local annual precipitation. Key environmental factors all had significant effects( all P<0.001) on the stand transpiration rate( E_s) of K. obovata forest,and photosynthetically active radiation( PAR) and vapor pressure deficit( VPD) were themain driving factors,which explained 60%-92% seasonal variation of E_s. The PAR and VPD had larger effects on the E_sin summer than that in winter. In addition,we observed an obvious time lag phenomenon in the relationship between E_sand PAR or VPD,which should be taken into account when explaining seasonal variation of E_sin K. obovata forest.国家自然科学基金项目(30930017);; 国家海洋局海洋公益性行业科研专项(201305021)资助~

鼠腹腔中弓形虫的增殖发育及S.D.对其的影响

对鼠腹腔中弓形虫速殖子的增殖发育的方式、过程及 S.D.对其的影响作了详细的考察 ,结果表明弓形虫的无性生殖方式有内二裂殖、纵二裂殖、裂殖生殖等 ,虫体以鼠腹腔内巨噬细胞的胞壁作为假包囊壁在其中增殖发育 ,经过 72 h的增殖生长 ,虫体成熟后突破假包囊逸出 ,S.D.可部分抑制速殖子增殖

Electroless copper plating on ceramics

为提高化学镀铜液的稳定性 ,在化学镀铜液中加入亚铁氰化钾和a ,a’ -联吡啶作为添加剂。研究了温度与陶瓷基体上化学镀铜沉积速度的关系 ,计算出铜沉积的活化能。当镀液中含有亚铁氰化钾或a ,a’ -联吡啶时 ,铜沉积活化能提高 ,铜沉积速率降低 ,镀铜层外观及镀液稳定性均得到改善。此外 ,镀液中同时含有亚铁氰化钾和a ,a’ -联吡啶时 ,镀液、镀层性能得到进一步提高。Potassium ferrocyanide and a,a'-dipyridine were added in electroless copper plating bath to improve the bath stability. Relationship between temperature and copper deposition rate on ceramics was studied, and the activated energy of copper deposition was calculated With the addition of potassium ferrocyanide and a, a'-dipyridine, the activated energy of copper deposition increased and copper deposition rate decreased, electroless copper plating is improved in deposit appearance and bath stability. Furthermore, better results can be obtained provided that potassium ferrocyanide and a,a'-dipyridine are used in combination

改进型铜基甲醇合成催化剂XC209的热稳定性

在 Cu- Zn- Al三组份的 C2 0 7型联醇催化剂中 ,添加 2种适量的过渡金属氧化物研制的XC2 0 9型联醇催化剂 ,经 4 50℃热处理 5h后 ,CO转化率比 C2 0 7型提高 8.6个百分点 .XRD和FTIR表征显示 ,工作态的改进型催化剂表面 Cu+ 活性浓度比 C2 0 7型高 ,热处理后能维持工作表面具有较大的 Cu+ /Cu°比 ,金属间相互作用加强了 ,这与改进型催化剂具有较高的热稳定性密切相关

双能谷效应对N型掺杂Si基Ge材料载流子晶格散射的影响

性能优越的Si基高效发光材料与器件的制备一直是Si基光电集成电路中最具挑战性的课题之一.Si基Ge材料不仅与成熟的硅工艺相兼容,而且具有准直接带特性,被认为是实现Si基激光器最有希望的材料.对Si基Ge材料N型掺杂的研究有利于提示出其直接带发光增强机理.本文研究了N型掺杂Si基Ge材料导带电子的晶格散射过程.N型掺杂Si基Ge材料具有独特的双能谷（Γ能谷与L能谷）结构,它将通过以下两方面的竞争关系提高直接带导带底电子的占有率:一方面,处于Γ能谷的导带电子通过谷间光学声子的散射方式散射到L能谷;另一方面,处于L能谷的导带电子通过谷内光学声子散射以及二次谷间光学声子散射或者直接通过谷间光学声子散射的方式跃迁到Γ能谷.当掺杂浓度界于1017cm-3到1019cm-3时,适当提高N型掺杂浓度有利于提高直接带Γ能谷导带底电子占有率,进而提高Si基Ge材料直接带发光效率.国家自然科学基金青年基金(批准号:61604041);;福建省自然科学基金青年基金(基金号:2016J05147);;福建省教育厅2017年高校杰出青年科研人才培育计划项目;;福建工程学院校科研启动基金(批准号:GY-Z14073)资助的课题~

Investigation of Mixed Potential in Electroless Ni-W-P Plating

　测量了化学镀Ni P和Ni W P过程混合电位随时间的变化,并分析其变化规律。指出Emix的正移与pH值随时间而降低有关,而且pH值的降低会加速化学镀的诱发过程。低碳钢诱发化学镀Ni W P会在混合电位 时间曲线上出现两个电位阶梯,其原因在于低碳钢在给定的镀液体系中稳定电位不够负,不能提供足够的能量使化学镀Ni W P快速发生,只有当表面形成达到一定覆盖度的具有催化活性的Ni原子层后,才能迅速地诱发化学镀过程;而Ni P和Ni W P的稳定电位足够负,可以使化学镀过程快速诱发,故仅有一个电位阶梯。The mixed potentials as a function of time were measured during the process of electroless Ni\|P and Ni\|W\|P plating, and their patterns were also analyzed. It was indicated that the positive shift of Emix was related to the pH value which decreased with time, and that the decrease in pH could accelerate the initiation of electroless plating. Two potential steps were observed on Emix\|t curves when the mild steel was used as the substrate of electroless Ni\|W\|P plating because of its less negative stable potential, which couldn't supply enough energy for rapid electroless deposition of Ni\|W\|P, and none but a layer of catalytic nickel with considerable coverage on mild steel was needed for rapidly initiating the electroless plating. However, since sufficient negative stable potentials, Ni\|P and Ni\|W\|P were able to initiate electroless deposition rapidly, hence only one potential step was found.国家自然科学基金资助项目(20073035

Effect of RF power on the structure and properties of ZnO∶Al films deposited by magnetron sputtering

采用RF磁控溅射技术以ZnO:Al2O3(2 wt%Al2O3)为靶材在石英玻璃衬底上制备多晶ZnO:Al(AZO)薄膜,通过XRD、AFM、AES以及Hall效应、透射光谱、折射率等手段研究了RF溅射功率(50~300 W)对薄膜的组织结构和电学,光学性能的影响。分析表明:所制备的AZO薄膜具有c轴择优取向,并且通过对不同功率下薄膜载流子浓度与迁移率的研究发现对于室温下沉积的AZO薄膜,晶粒间界中的O原子吸附是影响薄膜电学性能的主要因素。同时发现当功率为250 W时薄膜的电阻率降至最低(3.995×10-3Ω.cm),可见光区平均透射率为91%。Aluminum doped zinc oxide films are deposited by magnetron sputtering using a zinc oxide target doped with Al2O3(2 wt%.) with different RF powers on quartz substrate.The structural and compositional characteristics of the films are investigated by XRD,AFM,SEM,AES and XPS.respctively,while the electrical and optical properties of the thin films are studied by the Hall measurement and spectrophotometry,respectively.It has been found that all films deposited are c-axis preferred orientation perpendicular to the substrate with porous crystalline structure.The lowest resistivity obtained in this study is 3.9×10-3 Ω·cm for the film deposited at 250 W,and the average transmittance is 91% in the visible range.By comparing the samples deposited at various RF power,the oxygen absorption in the grain boundaries is the dominant factor which influences the electrical property of the AZO thin film

Carbon and Nutrient Pools of Coarse Woody Debris in a Natural Forest and Plantation in Subtropical China

福建三明格氏栲天然林及在其采伐迹地上营造的33年生格氏栲人工林和杉木人工林粗木质残体现存量与季节动态、C库及养分库的研究表明,格氏栲天然林、人工林和杉木人工林粗木质残体现存量分别为1 32、0 4 6和0 2 3t·hm- 2 。3种林分粗木质残体现存量的季节变化模式均为夏季>冬季>秋季>春季。格氏栲天然林粗木质残体C贮量为0 78t·hm- 2 ,分别是格氏栲人工林和杉木人工林的4 1 1倍和7 0 9倍;格氏栲天然林粗木质残体C库与2种人工林间差异显著(P <0 0 5)。格氏栲天然林、人工林和杉木人工林粗木质残体养分贮量分别为1 4 1 6、2 90和0 95kg·hm- 2 ;格氏栲天然林粗木质残体中各种养分贮量均最高。与人工林相比,天然林粗木质残体现存量、C和养分贮量均最大。 【英文摘要】 During the past decades, large scale natural forests had been converted to fast growing and high yield commercial plantations to meet the demands for timber, fuel material, and other forest products. Some silvicultural measures, such as planting pure stands, clear cutting and slash burning, were widely applied during this conversion. Yield decline and land deterioration in such disturbed ecosystems had become serious. In this context, the ecological comparisons between natural forests and plantations have...福建省重大基础研究项目 (2 0 0 0F0 0 4 ) ;; 高等学校优秀青年教师教学科研奖励计划资助

Comparative studies on carbon storage and litterfall dynamics between secondary and primary mangrove communities in Zhanjiang,Guangdong Provinces,China

通过群落调查、异速生长法计算以及样品测定,分别对2010~2011年期间广东湛江高桥红树林生态系统中次生桐花树和原生木榄群落的植物和土壤储量进行了计算,并利用掉落物收集筐对掉落物动态进行了比较研究。研究结果表明,高桥桐花树与木榄群落的植物碳库(以C计,下同)分别为(51.16±12.06)x106g/HM2和(38.52±6.94)x106g/HM2,地上部分明显高于地下部分;土壤碳库分别为(111.86±7.96)x106g/HM2和(106.13±11.12)x106g/HM2,明显高于植物碳库;次生与原生红树林群落的总碳库没有差异(P>0.05)。桐花树和木榄群落的年均掉落物产量分别为556.00 g/M2和971.13 g/M2,均以凋落叶居多,但原生木榄群落的掉落物产量明显高于次生桐花树群落(P 0.05).The mean annual litterfall production for the B.gymnorrhiza community was 971.13 g DW / m2,significantly higher than that of the A.corniculatum community( 556.00 g / m2,P < 0.001).In conclusion,the carbon pools in the secondary A.corniculatum community were comparable with those for the primary B.gymnorrhiza community,but much lower than those for the primary mangrove communities in the tropical regions.国家自然科学基金重点项目(30930017); 国家海洋公益性行业科研专项经费项目(200905009;201305021

Litter production, nutrient return and leaf-litter decomposition in natural and monoculture plantation forests of Castanopsis kawakamii in subtropical China

通过对中亚热带格氏栲天然林 ( natural forest of Castanopsiskawakamii,约 1 5 0年生 )、格氏栲和杉木人工林 ( monoculture plantations of C.kawakamii and Cunninghamia lanceolata,33年生 )凋落物数量与季节动态、养分归还及凋落叶分解与其质量的关系为期 3a的研究表明 ,林分年均凋落量及叶所占比例分别为 :格氏栲天然林 1 1 .0 1 t/hm2 ,5 9.70 t/hm2 ;格氏栲人工林 9.5 4 % ,71 .98% ;杉木人工林 5 .47t/hm2 ,5 8.2 9%。格氏栲天然林与人工林凋落量每年只出现 1次峰值 ( 4月份 ) ,而杉木林的则出现 3次 ( 4或5月份、8月份和 1 1月份 )。除杉木林的 Ca和格氏栲人工林的 Mg年归还量最大外 ,N、P、K及养分总归还量均以格氏栲天然林的为最大 ,杉木人工林的最小。分解 1 a后格氏栲天然林中格氏栲叶的干重损失最大( 98.1 6% ) ,杉木叶的最小 ( 60 .78% )。C/N及木质素 /N比值与凋落叶分解速率呈显著负相关 ,而 N、水溶性化合物初始浓度与分解速率呈显著正相关。与针叶树人工林相比 ,天然林的凋落物数量大、养分归还量高、分解快 ,具有良好自我培肥地力的能力。因此 ,保护和扩大常绿阔叶林资源已成为南方林区实现森林可持续经营的重要措施之一。The amount and pattern of litterfall, its nutrient (N, P, K, Ca and Mg) returns, and leaf-litter decomposition associated with its quality were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata, CF) in Sanming, Fujian, China. Mean annual total litterfall over 3 years of observations (from 1999 to 2001) was 11.01 t·hm -2 in the NF, 9.54 t·hm -2 in the CK and 5.47 t·hm -2 in the CF respectively. Of the total annual litterfall in the three forests, leaf contribution constituted 59.70%, 71.98% and 58.29%, respectively. Litterfall in the NF and CK showed similar litterfall pattern with a distinct peak in April of each year. While for the CF, the litterfall peaks occurred in April (or May), August and November, respectively. Except for the highest annual Ca returns in the CF and Mg returns in the CK, the three forests could be arranged in this sequence with respect to annual nutrient returns: NF>CK>CF. The annual percent leaf litter mass loss was the highest for C. kawakamii in the NF (98.16%) and the lowest for Chinese fir (60.78%). Ratios of C/N and lignin/N had significantly negative influences on decay rate coefficients, while initial N and water soluble compounds exerted significantly positive influences. The results of this study demonstrate that the natural forest has a greater capability for maintaining site productivity than monoculture plantations due to higher amount and quality of litter coupled with greater nutrient returns and faster litter decomposition. Therefore, conservation of the natural forest is recommended as a practical measure in forest management to realize sustainable development of forestry in mountainous areas of southern China.中国博士后科研基金资助项目;; 教育部高等学校优秀青年教师奖资助项目;; 教育部高等学校骨干教师资助计划资助项目;; 福建省重大基础研究资助项目 ( 2 0 0 0 F0 0 4)~