低盐水体Na^(+)/K^(+)对凡纳滨对虾生长、体成分与肝胰腺、鳃组织结构的影响

缺钾在内陆低盐度盐碱水中经常发生,为探究低盐水体中不同钾缺乏程度对凡纳滨对虾生长、存活、体成分以及鳃和肝胰腺组织结构的影响,实验参照海水离子组成配置盐度为2的低盐度水体,在Na^(+)/K^(+)(mg/mg)比值为27、47、67、87、107 (分别记为A、B、C、D、E组)的条件下,对体重为(1.04±0.23) g的凡纳滨对虾幼虾开展了为期60 d的养殖实验。结果显示,E组对虾的存活率为44.64%±20.95%,显著低于A、B、D三组;E组体重为(4.86±0.66) g,显著低于其他4组;A~D组之间的湿重、增重率、特定生长率差异不显著,但均大于E组且差异显著;在饲料系数上,E组最高并与A、D组差异显著。在体成分上,各组全虾钾含量、灰分含量差异不显著,E组的水分含量高于其他组,并与A、B组差异显著;E组粗蛋白含量最低,且与B组差异显著。E组对虾鳃组织角质层明显受损,红细胞数量减少,空泡增多,肝胰腺B细胞及其内部转运泡体积增大,肝小管结构受损。研究表明,低盐条件下严重缺钾引起了对虾鳃和肝胰腺损伤,降低了对虾的存活率和生长率;水体缺钾在前期即可对对虾的生长产生明显影响,而对存活的影响随养殖时间的增加而增大。实验结果有助于为内陆低盐度盐碱水养殖凡纳滨对虾提供理论依据。

亚硝酸盐急性胁迫对凡纳滨对虾免疫功能及鳃Na^(+)/K^(+)-ATP酶活性的影响

试验旨在研究亚硝酸盐急性胁迫对凡纳滨对虾(Litopenaeus vannamei)免疫功能及鳃Na^(+)/K^(+)-ATP酶活性的影响。选择平均体重为(1.68±0.23)g的凡纳滨对虾600尾,随机分为5组,每组3个重复,每个重复40尾虾。设置亚硝酸盐浓度分别为0(对照组)、0.4、0.8、1.6、3.2 mg/L,急性胁迫96 h。分别在胁迫0、12、24、48、72、96 h取样,测定其肝胰腺免疫功能相关指标和鳃Na^(+)/K^(+)-ATP酶活性。结果显示:各胁迫组凡纳滨对虾肝胰腺超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)和乳酸脱氢酶(LDH)的活性均受胁迫时间延长总体呈先升后降趋势。3.2 mg/L组凡纳滨对虾肝胰腺SOD、CAT、GSH-Px、ACP活性在胁迫96 h时均降至对照组水平;LDH活性在胁迫24 h时降至对照组水平,后持续下降至显著低于对照组水平(P<0.05)。除0.4 mg/L组凡纳滨对虾肝胰腺丙二醛(MDA)含量在胁迫96 h时降至对照组水平外,其余各组的MDA含量在胁迫96 h内均显著高于对照组(P<0.05)。在胁迫96 h内,0.4 mg/L组凡纳滨对虾鳃Na^(+)/K^(+)-ATP酶活性持续上升;0.8~3.2 mg/L组凡纳滨对虾鳃Na^(+)/K^(+)-ATP酶活性均随胁迫时间延长呈先激活后抑制趋势,且3.2 mg/L组在胁迫96 h时降至对照组水平。研究表明,在0.4~3.2 mg/L亚硝酸盐急性胁迫下,凡纳滨对虾免疫功能和鳃Na^(+)/K^(+)-ATP活性受到影响,当盐度为(24.0±1.0)‰时,需要控制凡纳滨对虾健康养殖过程中亚硝酸盐含量在0.4 mg/L以内。

盐霉素通过Na^(+),K^(+)-ATP酶诱导脂肪干细胞和肝癌干细胞胀亡的作用机制研究

目的观察脂肪干细胞(ASCs)和肝癌干细胞(HCCSCs)对盐霉素处理的反应,探讨Na^(+),K^(+)-ATP酶在盐霉素选择性杀伤ASCs和HCCSCs中的作用。方法采用CCK-8、Transwell实验分析盐霉素对ASCs及HCCSCs的细胞毒性反应,显微镜下观察细胞形态变化,采用Na^(+),K^(+)-ATP酶检测试剂盒测定细胞内Na^(+)和K^(+)离子浓度,通过ATP检测试剂盒测定细胞内ATP浓度。采用Western blot法分析Na^(+),K^(+)-ATP酶各亚基及细胞上皮间质转化(EMT)相关蛋白的表达水平。通过上述方法验证盐霉素通过调控Na^(+),K^(+)-ATP酶诱导ASCs和HCCSCs胀亡(细胞肿胀、坏死)的作用机制。结果盐霉素选择性诱导ASCs和HCCSCs胀亡。在胀亡的ASCs和HCCSCs中,细胞内ATP浓度显著下降,伴随Na^(+),K^(+)-ATP酶活性丧失和细胞内Na^(+)滞留。所有类型的Na^(+),K^(+)-ATP酶亚基在ASCs中均有表达,而在盐霉素诱导分化的ASCs中仅表达α1和β1亚基。β1亚基的丧失是阿霉素诱导肝癌Huh-7细胞EMT的关键事件,相反β1亚基的过表达可以抑制阿霉素诱导的Huh-7细胞EMT。结论Na^(+),K^(+)-ATP酶的活性差异是盐霉素对干细胞产生选择性细胞毒性的原因,且β1亚基是肝癌EMT过程中一个重要因素。Na^(+),K^(+)-ATP酶亚基对ASCs和HCCSCs的干性及癌症干细胞样的EMT过程起关键作用。

盐度驯化对虹鳟和金鳟Na^(+)/K^(+)-ATP酶活力、皮质醇含量及其组织结构的影响

为探究不同盐度驯化对虹鳟(Oncorhynchus mykiss)和金鳟(Oncorhynchus mykiss)的鳃的影响,以盐度0为对照,研究了15‰和30‰两种盐度驯化虹鳟和金鳟后,鱼体鳃、血清中Na^(+)/K^(+)-ATP酶活力、血清中皮质醇含量和鳃、肾脏的组织学变化。试验结果表明,与对照组相比,低盐度下随驯化盐度提高,虹鳟、金鳟鳃部Na^(+)/K^(+)-ATP酶活力均呈增加趋势,但高盐度驯化时二者鳃部Na^(+)/K^(+)-ATP酶活力受抑制,血清中Na^(+)/K^(+)-ATP酶活力较低,且活力随盐度变化不大。血清皮质醇浓度随着驯化盐度增加而升高,盐度30‰条件下虹鳟和金鳟血清中皮质醇的含量达到最高值。虹鳟和金鳟的组织切片结果显示,驯化盐度过高时对二者肾脏和鳃组织均造成破坏,肾脏组织表现为肾小囊及肾小球遭到破坏并完全消失,鳃组织出现明显的氯细胞数量激增和鳃丝上皮脱落且鳃丝变细变长。

利拉鲁肽通过调控自噬和Na^(+),K^(+)-ATPase活性抑制高糖诱导的心肌细胞肥大

目的探讨利拉鲁肽(liraglutide,LRG)抑制高糖(HG)诱导的心肌细胞肥大的可能机制。方法体外培养H9c2细胞,分为对照(CON)组、HG组、低、中、高剂量LRG(LRG-L、LRG-M、LRG-H)组、LRG-H+自噬抑制剂3-甲基腺嘌呤(3-MA)组。鬼笔环肽染色观察细胞表面积;试剂盒测定细胞膜Na^(+),K^(+)-ATPase(NKA)活性;Real time-PCR和Western blot测定NKAα1、NKAα2 mRNA和蛋白表达;单丹磺胺戊二胺(MDC)荧光染色观察自噬囊泡数量;Western blot测定肥大标志基因(ANP、β-MHC)、自噬标志基因(Beclin-1、LC3、p62)蛋白表达。随后将H9c2细胞分为CON组、HG组、LRG-H组、LRG-H+Sirt1抑制剂EX 527组、LRG-H+AMPK抑制剂Compound C(CC)组,再次检测上述指标;Western blot测定Sirt1/AMPK/mTOR通路相关蛋白表达。结果LRG可抑制心肌细胞肥大,下调ANP、β-MHC蛋白表达;LRG可促进NKA活性恢复,上调NKAα2 mRNA和蛋白表达;LRG可增加自噬囊泡数量,上调Beclin-1、LC3-Ⅱ/LC3-Ⅰ蛋白表达,下调p62蛋白表达;LRG可上调Sirt1、p-AMPK/AMPK蛋白表达,下调p-mTOR/mTOR蛋白表达;使用自噬抑制剂3-MA、Sirt1抑制剂EX 527、AMPK抑制剂CC则部分逆转了LRG的作用。结论LRG可抑制高糖所致心肌细胞肥大,其机制与调控Sirt1/AMPK/mTOR通路激活自噬及促进NKA活性恢复有关。

温阳益气活血方对慢性心力衰竭大鼠心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶的影响

目的观察温阳益气活血方对慢性心力衰竭大鼠心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶的影响,探讨其治疗心力衰竭的作用机制。方法采用皮下多点注射异丙肾上腺素制备慢性心力衰竭大鼠模型,将成模大鼠随机分为模型组、西药组和温阳益气活血方低、中、高剂量组,每组14只,另设空白组15只,给药组分别予相应药物灌胃,空白组和模型组予等量生理盐水,连续6周。超声检测大鼠心功能,ELISA检测血清脑钠肽(BNP)含量,计算心脏质量指数(HMI),HE染色观察心肌组织病理变化,酶活比色法、免疫组化及RT-PCR检测心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶活性及表达。结果与空白组比较,模型组大鼠左室射血分数(LVEF)、左室短轴缩短率(LVFS)显著降低(P<0.01);血清BNP含量显著增加,HMI显著升高(P<0.01);心肌组织大量纤维水肿,胞质疏松,组织边缘心肌纤维溶解,伴有少量淋巴细胞浸润;心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶活性显著减弱,蛋白及mRNA表达显著降低(P<0.01)。与模型组比较,温阳益气活血方高剂量组大鼠LVEF、LVFS显著升高(P<0.01);血清BNP含量显著减少,HMI显著降低(P<0.05,P<0.01);心肌纤维水肿、胞质疏松、炎症浸润、细胞空泡变性及纤维溶解程度均有改善;心肌组织Na^(+)-K^(+)-ATP酶和Ca^(2+)-ATP酶活性显著增强,蛋白及mRNA表达显著升高(P<0.01)。结论温阳益气活血方能通过调节心肌Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶活性及表达改善心力衰竭大鼠心功能不全,发挥治疗慢性心力衰竭的作用。

盐胁迫下外源脯氨酸对油菜Na^(+)/K^(+)平衡、生长及抗氧化系统的影响

为探究盐胁迫下外源脯氨酸对油菜生长发育的调控机制,以甘蓝型油菜为试验材料,在150 mmol/L盐胁迫下设置5个外源脯氨酸水平(0、0.25、0.5、1和2 mmol/L),探究外源脯氨酸对盐胁迫下抗氧化系统、渗透物质和离子含量的影响。结果显示:盐胁迫显著抑制油菜的生长,较低浓度(0.25 mmol/L和0.5 mmol/L)外源脯氨酸均可促进油菜的生长,相比0.25 mmol/L外源脯氨酸,施用0.5 mmol/L对油菜长势具有较好的促进作用,能够减少叶片Na^(+)积累,提高K^(+)含量,提高抗氧化酶的活性,并降低活性氧含量。另外,0.5 mmol/L外源脯氨酸还可以促进油菜叶片脯氨酸等渗透物质的积累。而施用较高浓度(1 mmol/L和2 mmol/L)外源脯氨酸不仅没有缓解盐胁迫,还对油菜叶片造成进一步的伤害。综上,盐胁迫会对油菜生长造成损伤,而施用适量外源脯氨酸能够激发抗氧化系统,有效缓解盐胁迫对油菜生长的抑制,提高油菜的耐盐性。

褪黑素通过H_(2)O_(2)调控盐胁迫下小豆Na^(+)/K^(+)平衡机制

为探究褪黑素对盐胁迫下小豆幼苗生长发育的影响,以保红876为材料,设置4个处理:CK(清水)、S(60 mmol/L NaCl)、MT(50μmol/L褪黑素)和S-MT(60 mmol/L NaCl和50μmol/L褪黑素),并分析了小豆幼苗生长指标、光合指标、矿质元素离子含量和抗氧化酶活性的变化。结果表明,在盐胁迫条件下,较CK处理,小豆幼苗的生长受到明显抑制,叶绿素含量、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和胞间CO_(2)浓度(Ci)显著降低;叶、茎中Na^(+)含量显著上升,叶片中Ca^(2+)含量显著上升而Mg^( 2+)含量则显著下降,豆苗Na^(+)/K^(+)比值显著增加;MDA和H_(2)O_(2)含量显著上升,破坏了膜脂选择透性。盐胁迫下施加褪黑素后,较S处理,显著提高了豆苗株高、叶面积和生物量,总根长显著增加;同时提高了叶绿素含量、叶片Pn、Tr和Ci;叶、茎中Na^(+)和K^(+)含量显著降低,叶片Mg^( 2+)含量显著升高同时Ca^(2+)含量显著降低,豆苗Na^(+)/K^(+)比值降低;MDA、O_(2)^(-)和H_(2)O_(2)含量下降;提高了叶片和根系SOD、POD和CAT活性。正常条件下,施加褪黑素可以促进豆苗的生长,提高幼苗的光合能力,提高了可溶性蛋白含量。对15个代表指标进行Spearman相关分析,发现总根长、叶绿素含量、净光合速率、抗氧化酶活性均与Na^(+)/K^(+)比值和ROS含量呈显著或极显著负相关。综上所述,盐胁迫下,褪黑素通过激活了豆苗抗氧化酶活性,可直接和间接的减少H_(2)O_(2)含量,保持膜脂渗透稳定性,从而利于植物体内Na^(+)/K^(+)平衡;同时,H_(2)O_(2)和Ca^(2+)作为信号分子,在褪黑素调节细胞内离子平衡的过程中存在协同效应,从而提高植物的耐盐能力。

盐度胁迫对彩虹明樱蛤存活、抗氧化酶和Na^(+)/K^(+)-ATP酶活性的影响

为探究彩虹明樱蛤(Moerella iribescens)对盐度胁迫的适应能力和调节机制,对其进行急性盐度胁迫实验,在盐度5~50之间设定10个盐度梯度(5,6,8,11,14,18,23,30,39,50),观察死亡情况。结果显示,盐度胁迫96 h后,盐度50组死亡率为100%,盐度39、30、23、6、5死亡率分别为43.3%、6.7%、3.3%、1.7%、8.3%,而盐度8~18之间的4个组中未发现死亡个体。根据急性胁迫实验结果设置5个盐度梯度(6、12、18、24、30),测定0、24、48、72、96 h鳃和消化腺超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)和Na^(+)/K^(+)-ATP酶活性变化。结果显示,在同一盐度胁迫下,彩虹明樱蛤鳃和消化腺的SOD、CAT、GSH-Px和Na^(+)/K^(+)-ATP酶活性随时间的变化呈先上升后下降并趋于稳定的变化趋势,不同盐度组SOD、CAT和GSH-Px活性在24 h或48 h达到高峰,不同盐度组Na^(+)/K^(+)-ATP活性在48 h或72 h达到高峰。研究表明,彩虹明樱蛤的适宜盐度为8~18,3种抗氧化酶对盐度胁迫响应时间短于Na^(+)/K^(+)-ATP酶。研究从生存适应和应激相关酶活性角度探讨了彩虹明樱蛤对盐度的响应,可为其养殖和保育提供科学依据。

Na_(2)O对锂铝硅微晶玻璃析晶及性能的影响

采用熔融法制备了不同Na_(2)O含量的透明锂铝硅微晶玻璃,通过DSC、XRD、FESEM等测试方法研究了不同Na_(2)O含量对玻璃析晶及性能的影响。结果表明:Na_(2)O的引入能显著降低玻璃的转变温度和析晶温度,抑制LiAlSi_(4)O_(10)晶相的析出。但Na_(2)O的引入促使微晶玻璃中析出Li_(2)Si_(2)O_(5)新相,并且随着Na_(2)O引入量的增加,Li_(2)Si_(2)O_(5)转变为主晶相。由于晶体尺寸均为纳米级,主晶相的转变对透过率影响较小,微晶玻璃的可见光透过率均高于85%。主晶相的转变有效增强了微晶玻璃的机械性能,其弯曲强度由300 MPa提升至331 MPa。Na_(2)O的引入有效增强了Na-K交换,Na_(2)O含量为4%(质量分数)的Li 2O-Al_(2)O_(3)-SiO_(2)微晶玻璃在410℃的KNO_(3)熔盐中交换6 h后,维氏硬度由7.108 GPa提升至7.403 GPa,弯曲强度由331 MPa提升至470 MPa。

Na-K协同作用对湿法脱硝NO_(x)演化过程的影响机制

以KMnO_(4)、NaClO_(2)为氧化剂进行模拟烟气吸收试验,探究单一碱液吸收剂、Na-K协同吸收剂对去除烟气中NO_(x)的影响,引入微量SO_(3)^(2-)离子对吸收效率进一步优化。结果发现,KOH碱液性能明显高于NaOH,30 min内KOH平均吸收率高达99.4%,NaOH的平均吸收率仅86.9%,这是K^(+)离子半径更大,更易解离OH^(-)所致。以0.1 mol/L的KMnO_(4)作为氧化剂、双组份吸收液(n(Na)∶n(K)=1∶2,n为物质的量浓度)效率更高更稳定,30 min仍可达86%,是双金属离子的电荷传递效应,使气相反应物向液相传递时气膜迅速破裂,减少了气液两相的扩散时间所导致,并通过DFT模拟计算充分证实了这一点。通过在吸收液中引入微量SO_(3)^(2-)离子,平均吸收率提高了3%,证明SO_(3)^(2-)离子进一步促进了硝酸盐物种的吸收转化。

(K,Na)NbO_(3)基无铅压电陶瓷温度稳定性的研究与进展

基于可持续发展的迫切需求,环保型无铅压电陶瓷成为当前压电铁电领域的研究前沿和热点之一.近年来,铌酸钾钠((K,Na)NbO_(3),KNN)基无铅压电陶瓷因其迅速提升的压电性能,备受研究者所关注,有望取代部分铅基压电陶瓷.特别是新型相界、纳米畴等调控手段有效提升KNN基陶瓷压电系数至部分铅基水平,使其表现出优异的应用前景,有望应用于加速度传感等器件.然而相比迅速发展的压电性能,KNN陶瓷的压电温度稳定性仍相对进展缓慢,主要归结于其多晶型相界的特征,阻碍其面向实际应用发展.因此,该文结合国内外研究进展,针对KNN基无铅压电陶瓷,重点介绍了其压电系数和电致应变的温度稳定性的研究进展,并对今后该陶瓷温度稳定性的研究提出了一些展望.

Identification of Rice Accessions Associated with K+/Na+ Ratio and Salt Tolerance Based on Physiological and Molecular Responses

The key for rice plant survival under Na Cl salt stress is maintaining a high K^+/Na^+ ratio in its cells. Selection for salt tolerance rice genotypes based on phenotypic performance alone will delay in progress in breeding. Use of molecular markers in tandem with physiological studies will help in better identification of salt tolerant rice accessions. Eight rice accessions along with the check Dongjin were screened using 1/2 Yoshida solution with 50 mmol/L NaCl at the seedling stage. The accessions IT001158, IT246674, IT260533 and IT291341 were classified as salt tolerant based on their K^+/Na^+ ratios. Seventeen SSR markers reported to be associated with K^+/Na^+ ratio were used to screen the accessions. Five SSR markers(RM8053, RM345, RM318, RM253 and RM7075) could differentiate accessions classified based on their K^+/Na^+ ratios. Banding pattern of the accessions was scored compared to the banding pattern of Dongjin. The study differentiated accessions based on their association of K^+/Na^+ ratio with molecular markers which are very reliable. These markers can play a significant role in screening large set of rice germplasms for salt tolerance and also help in identification of high-yielding varieties with better salt tolerance. The salt tolerant accessions can be taken forward into developing better varieties by conventional breeding and exploring genes for salt tolerance.

Phase Structure, Microstructure and Electrical Properties of K_xNa_((1-x))NbO_3 Piezoelectric Ceramics with Different K/Na Ratio

The K_xNa_((1-x))NbO_3(x=0.45, 0.46, 0.47, 0.48, 0.49, 0.50) lead-free piezoelectric ceramics was fabricated by conventional solid-state sintering method. It was found that the ratio of alkaline metal would affect the microstructure, bulk density, and optimum sintering temperatures of ceramics. Meanwhile, the electrical properties were also influenced by modulating the K/Na ratio, exhibiting corresponding composition-dependent properties. The optimum electrical properties of K_xNa_((1-x))NbO_3 such as piezoelectric constant d_(33) = 115 pC/N, mechanical quality factor Q_m = 20, Curie temperature Tc = 365 ~oC, ε_(33)~T/ε_0= 588.1, dielectric loss tan δ = 0.024, bulk density(ρ) = 3.08 g/cm^3, remnant polarization(P_r) = 8.87 μC/cm^2 and coercive field(Ec) = 13.79 kV/cm were obtained at x = 0.46.

Effect of various Na/K ratios in low-salinity well water on growth performance and physiological response of Pacific white shrimp Litopenaeus vannamei

To investigate the influence of sodium to potassium （Na/IO ratios on the growth performance and physiological response of the Pacific white shrimp （Litopenaeus vananmei）, various concentrations of KC1 were added to low-salinity well water （salinity 4） in an 8-week culture trial. Six treatments with NWK ratios of 60：1, 42：1, 33：1, 23：1, 17：1, and 14：1 were replicated in triplicate. The highest weight-gain rate （3 506±48）% and survival rate （89.38±0.88）% was observed in well water with Na/K ratios of 23：1 and 42：1, respectively, while the feed conversion ratio （1.02～0.01）, oxygen consumption, and ammonia-N excretion rate was the lowest in the medium with a Na/K ratio of 23：1. Gill Na＋-K＋-ATPase activity, as an indicator of osmoregulation, peaked in the treatment where the Na/K ratio was 17：1. The total hemocyte count, respiratory burst, and immune-related enzyme activities （ALP, LSZ, PO, and SOD） ofL. vananmei were affected significantly by Na/K ratios （P〈0.05）. After challenged with Vibrio harveyi, the cumulative mortality of shrimp reared in a Na/K ratio of 23：1 （30±14.14）% was significantly lower than the control （75～7.07）%. In conclusion, the addition of K＋ to low-salinity well water in L. vannamei cultures is feasible. Na/K ratios ranging from 23：1 to 33：1 might improve survival and growth. Immunity and disease resistance are also closely related to the Na/K ratio of the low-salinity well water. The findings may contribute to the development of more efficient K^＋ remediation strategies for L. vananmei culture in low-salinity well water.

Preparation of Layered Potassium Titanate Whiskers with Large Length-diameter Ratio by KDC Method

Pure K2Ti4O9 whiskers were prepared by KDC（Kneading-Drying-Calcination） method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio（RT/K）, calcination temperature（TC） and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC（thermo gravimetric-differential scanning calorimeter）, XRD（X-ray diffraction）, and SEM（scanning electron microscope）. Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio（r）（over 250） can be obtained at RT/K = 2.9 and TC = 950 ℃.

Preparation and Piezoelectric Properties of CuO-added(Ag_(0.75)Li_(0.1)Na_(0.1)K_(0.05_)NbO_3 Lead-free Ceramics

CuO-doped（Ag0.75Li0.1Na0.1K0.05）NbO3（ALNKN-xCuO, x = 0.2mol%） lead-free piezoelectric ceramics were prepared by the solid-state reaction method in air atmosphere. The effects of CuO addition on the phase structure, microstructure, and piezoelectric properties of the ceramics were investigated. The experimental results show that the ALNKN ceramics without doping CuO possess rhombohedral phase along with K2NbrO16- type phase and metallic silver phase. For all of the CuO-doped ALNKN ceramics, a pure perovskite structure with the orthorhombic phase was obtained by enclosing the samples in a corundum tube. A homogeneous microstructure with＇the grain size of about 1 ~tm was formed for the ceramics with 0.5mo1% CuO. The grain size increases with increasing amount of CuO. The temperature dependence of dielectric properties indicates that the ferroelectric phase of the ALNKN-xCuO ceramics becomes less stable with the addition of CuO. The ceramics with x = lm01% exhibit relatively good electrical properties along with a high Curie temperature. These results will provide a helpful guidance to preparing other AN-based ceramics by solid-state reaction method in air atmosphere.

盐胁迫对不同品系萱草Na^(+)·K^(+)含量与分布的影响

通过对盐胁迫条件下不同品系萱草的Na^(+)、K^(+)含量及分布进行测定和分析,探究其抗盐机理,为萱草在盐渍地区的生态应用和品种选育提供理论支撑。以8个品系萱草为材料,采用水培方法进行150 mmol/L NaCl胁迫处理,将盐胁迫和非盐条件下不同品系萱草分嫩叶、成熟叶、老叶、茎和根5个部分,对各部分干物质含量,Na^(+)、K^(+)的积累和分布进行分析并探讨各指标与不同品系萱草耐盐性的相关关系。结果显示,盐胁迫处理对各品系萱草根系生物量积累的抑制作用最大,对嫩叶和老叶的干重积累无明显影响;盐胁迫使不同品系萱草各部位Na^(+)含量均显著上升,其中老叶的Na^(+)积累远大于其他部分,茎的变化量最小;盐胁迫对K^(+)的影响主要发生在老叶和成熟叶,其中YC-1、TG-1、TY-1、ZZ-2和WT-2表现为下降,ZZ-1表现为上升,而LS-1和JC-1无明显变化;盐胁迫下萱草Na^(+)/K^(+)的变化幅度为老叶>成熟叶>嫩叶>根>茎。通过主成分分析和隶属函数,对各品系萱草进行基于干物质含量和Na^(+)/K^(+)的耐盐性评价,8个品系萱草耐盐性为ZZ-1>ZZ-2>WT-2>YC-1>TG-1>TY-1>LS-1>JC-1。综上所述,萱草在盐胁迫条件下对Na^(+)、K^(+)的积累呈明显的不均衡分布特征,各部位干重及Na^(+)/K^(+)的变化可作为评价不同品系萱草耐盐能力的指标。

原子吸收分光光度法测定合成甲醇催化剂成品中的Fe、Ni、K、Na含量

本文建立了用原子吸收分光光度法测定合成甲醇催化剂成品中的Fe、Ni、K、Na的杂质含量分析方法。选择并优化了测试条件、定量方法,找到方法的线性范围及检出限,其测定简便、分析速度较快,结果准确度好、精密度高,对其实验条件和分析性能进行了详细的探讨,结果令人满意,该方法可用于测定甲醇催化剂中Fe、Ni、K、Na的含量。

Preparation and Tunable Luminescence of Eu Doped KNN Ceramics

Rare-earth doped inorganic ferroelectrics are considered as novel photochromic materials,with potential applications for optical switch and information storage(K0.5Na0.5)1–xEuxNbO3(KNN:xEu)ceramics were prepared by high temperature calcination,with precursor powder obtained by hydrothermal method.Strong red emission at 615 nm was observed which corresponds to the 5D0→7F2 transition of Eu3+under excitation of 465 nm.Under UV light irradiation for 3 min,the color of the ceramics turned from milky white to dark gray.The colored samples returned to the original color when heated at 200℃for 10 min,showing strong photochromic behavior.Meanwhile,the luminescence intensity of Eu3+can be tuned without obvious degradation by alternating UV light and heat stimulus.Upon UV light irradiation,large luminescence modulation ratio(ΔRt)up to 83.9%was achieved for KNN:0.06Eu,indicating good luminescence switching behavior.A possible mechanism for non-radiative energy transfer from the luminescent center to the color center was proposed according to their luminescent behavior.