再生碳纤维电极的新方法

本文根据火焰熔融法自制碳纤维电极的特点，提出了一种简便、易行的火焰灼烧再生电极的新方法。由此法再生电极的各种性能与原电极相当，结果令人满意。     

车前的离体培养和植株再生

报道了国丧外植体的愈伤组织诱导及其植株再生的研究结果,单独的外源生长素２,４－Ｄ适宜诱导外植体脱分化产生愈伤组织。再生芽的分化只需添加６－ＢＡ;当ＮＡＡ与６－ＢＡ配合添加于培养基中时,则有利于再生根的繁茂生长,从而形成完整的再生植株。     

脱色阴离子交换剂的再生研究

提出一种新的离子交换剂再生理论，即吸附物的脱附依靠离子交换和络合的协同效应完成．以二价钙离子为再生剂，对糖液脱色用的阴离子交换树脂和阴离子交换纤维进行再生，并与传统的碱性钠盐相比较，研究证明钙离子为再生剂的工艺，具有低成本、无污染的特点．     

应用原生质体融合技术选育L-异亮氨酸生产菌

以黄色短杆菌WY10和ASL495为亲本菌株，分别摸索了其原生质体形成和再生的条件，并在此基础上，进行了原生质体融合试验，考察了PEG浓度、融合时间等条件对原生质体融合的影响；最后利用所确定的条件对两亲株进行了融合，筛选出目的融合子WYA09和WYA17，带有双亲株标记Met^-和Leu^-。经产酸验证后，产酸量没有大幅提高，但副产氨基酸(主要是亮氨酸)减少，对工业生产中分离提纯工作和下一步的筛选高产菌工作都大有益处。     

长白山区次生林恢复过程中天然更新的动态

以长白山区天然次生林为研究对象,采用空间代替时间的方法,分别对不同年度进行择代后形成的天然次生林进行群落学调查,分析择伐后28年恢复期间高度小于3m的幼苗幼树的天然更新过程及特点。结果表明,恢复初期更新幼苗幼树的树种出现比率较低,随着次生林恢复时间的增加,更新幼苗幼树的树种出现比率超过75％,且15年后变化相对较小;次生林内更新幼苗幼树的分布密度随着恢复时间的增加呈增加的趋势,恢复15年时分布密度达7500株／hm^2,此后分布密度的变化相对较小;在次生林内幼苗幼树主要是集中分布在距最近立木1．5～3．5m的范围内,随着次生林恢复时间的增加,幼树的分布范围相对靠近立木,幼苗的分布范围则相对远离立木。     

林火干扰对栎类群落幼苗天然更新的影响

依据空间代替时间的方法,研究地表火干扰下不同恢复阶段栎类幼苗库的动态特征。结果表明:火后不同恢复阶段栎类群落内有木本幼苗25科37属49种,随着火烧迹地植被的恢复,乔木幼苗种类数量增多,灌木幼苗数量减少,但栎类幼苗始终占据优势;林下幼苗库的密度随恢复时间增加逐步变小,栎类幼苗密度则呈现出从高到低再升高然后变低的趋势,栎类幼苗密度在火后1年最高,平均达到(2.30±2.9)株/(10 m2);栎类幼苗密度变化出现2个过程,恢复1年与恢复5年、恢复10年与恢复15年幼苗密度之间有显著差异,但不同恢复阶段的栎类幼苗库与对照林相比没有显著差异;幼苗库不同恢复阶段的Shannon-Wiener指数(H′)之间有极显著差异。随演替时间的增加,乔木实生苗比例逐渐增加,乔木根蘖苗的比例不断减少。林火干扰对栎类Ⅰ、Ⅱ和Ⅲ的幼苗高度分配和苗木转化率有显著影响,但火烧干扰对Ⅳ级以上幼苗的高度分布和转化率影响不显著。     

稀释蒸汽中Na+及积炭对甲醇制丙烯催化剂性能影响

考察了稀释蒸汽中Na⁺及积炭对甲醇制丙烯(MTP)催化剂物理化学性质和催化性能影响, 及离子交换后催化性能. 采用X射线衍射(XRD)、扫描电镜(SEM)、X射线荧光(XRF)光谱、N₂吸附-脱附、程序升温氨脱附(NH3-TPD)和热重(TG)分析等方法对失活和再生催化剂进行了表征, 并在101325 Pa、470℃ 和甲醇空速(WHSV)为1.0-3.0 h^-1的反应条件下, 采用连续流动固定床微型反应器考察其催化甲醇制丙烯性能. 结果表明: MTP反应970 h后的催化剂晶体结构和形貌没有受到明显破坏, 但稀释蒸汽中Na⁺极易扩散至催化剂表面,部分取代H质子的位置, 从而使催化剂酸性逐渐下降而中毒失活; 另外, MTP催化剂表面的积炭导致分子筛微孔堵塞是造成其失活的主要原因, 可通过烧炭再生过程消除, 而水蒸汽脱铝对催化剂性能的影响缓慢但更严重. 用再生和离子交换处理后, Na⁺中毒催化剂MTP反应性能基本完全恢复. 在470 h反应过程中, 甲醇转化率保持在99%以上, 丙烯选择性大于46%, 且随着反应时间的延长, 丙烯选择性逐渐升高、乙烯选择性逐渐下降.     

Ag(I)-catalyzed C–H borylation of terminal alkynes

An efficient Ag(I)-catalyzed borylation method of terminal alkynes is reported. The obtained borylated alkynes are shown to engage in C–Br, C–CN, C–N, and C–C bond formation with various reaction partners. Meanwhile the Ag(I) catalyst could be regenerated in the presence of PPh₃ and BF₃.     

An overview of heterogeneous photocatalysis for the degradation of organic compounds: A special emphasis on photocorrosion and reusability

Heterogeneous photocatalysis has been extensively investigated for the degradation of organic pollutants from wastewater. The remarkable advantages of the heterogeneous photocatalysis process depend upon its ability to produce reactive oxygen species under visible/UV/solar light irradiation. However, the long-term stability and reuse potential of these catalysts are of great concern these days, yet understudied. This review aims to systematically present a state of the art understanding of such catalysts' reuse potential. Various important surface characteristics of the photocatalysts for improving the photostability and activity of the catalyst are discussed. Besides, the synergistic effect of different surface modified materials, composite materials and their surface characteristics for their enhanced activity are also covered. Finally, a discussion on various regeneration processes used for such catalysts is also presented, identifying some vital research needs in this field.     

Highly reusable chitosan-stabilized Fe-ZnO immobilized onto fiberglass cloth and the photocatalytic degradation properties in batch and loop reactors

The new design of the photocatalytic reactor is crucial to study for improving compatibility and scaling up the operation. A compatible loop photocatalytic reactor has been designed and used for rhodamine B decomposition. The photocatalysts were either ZnO or Fe-ZnO immobilized onto fiberglass cloth. The ZnO catalyst exhibited high crystallinity with or without Fe as the dopant. The crystallite size increased with the presence of Fe in the lattices. Most of the crystal parameters matched the standard ZnO data, and the cluster size was comparable to most reported studies. Diffuse Reflectance Spectroscopy (DRS) analysis confirmed the photon absorption shifted to the visible light range. The Fe dopant decreased the ZnO bandgap, and SEM-EDS confirmed the catalysts adhered to the fiberglass surface. The volume, thickness of the substrate solution, and reaction temperature influenced the photocatalytic-degradation rate. The photocatalytic degradation rate was higher under sunlight than ultraviolet irradiation. The reaction rate was lower in the batch reactor than in the loop reactor. The photocatalytic reaction almost completely mineralized RhB and changed the red solution to colorless. The immobilized photocatalyst has been reused more than 50 times without significantly decreasing the catalytic activity.