Alkaline pulping with additives. A review

Summary The technology and chemistry of recent advances in alkaline pulping are reviewed from the standpoint of the authors' work over the past few years. Topics reviewed include soda-amine [particularly soda-ethylenediamine (EDA)], soda-anthraquinone (AQ), kraft-AQ, and soda-AQ/EDA pulping and their effects on pulp strength properties and bleachability. There is evidence to support the concept that the rates of all alkaline delignification reactions, including kraft, are controlled by a reductive step which transfers electrons to the degrading lignin.     

Explosion pulping of eucalyptus: a comparison with CTMP and CMP

Summary Explosion pulping results in strong pulp with breaking length at 100 ml CSF (Canadian standard freeness) higher than 6.5 kg and burst index approaching 4 KPa m²/g. The real advantage of eucalyptus explosion pulp over conventional CMP (chemical-mechanical pulp) and CTMP (chemical-thermo-mechanical pulp) is observed when the impregnation solution contains less than 2% NaOH along with 8% Na₂SO₃, and when the liquor/chips ratio equals 3. The strength of eucalyptus explosion pulp obtained by using a pretreatment solution consisting of 8% Na₂SO₃ and 1% NaOH is comparable with that of eucalyptus kraft pulp. The concentration of NaOH present in the pretreatment solution has a very important effect on the specific refining energy of eucalyptus explosion pulp as well as of CMP and CTMP. The explosion pulp obtained from eucalyptus pretreated with a solution containing an appropriate quantity of caustic along with Na₂SO₃ not only requires a minimum specific refining energy but also provides the highest strength values in comparison to that of CMP and CTMP.     

Chemical aspects of kraft pulping

Summary Kraft pulping is interpreted in chemical terms on the basis of results from extensive qualitative and quantitative model experiments. In essence, the behavior of lignin is explained as a competition between degradation reactions, mainly involving aryl ether cleavage with participation of neighboring groups, and condensation reactions, comprising conjugate addition of carbanions to quinone methide intermediates. The initial phase of technical delignification is tentatively ascribed to the cleavage of - and -aryl ether bonds in phenolic lignin units, whereas the cleavage of -aryl ether bonds in non-phenolic lignin units is considered to be the rate-determining reaction of the bulk phase. The residual phase may possibly be attributed to the rupture of C-C linkages and to aryl ether cleavage without neighboring group participation. Experimental support for these correlations is provided. The interplay of the various lignin reactions, illustrated in a summarizing scheme, explains some known observations in kraft pulping.Attention is drawn to analogies between reactions involved in the degradation of carbohydrates and those reponsible for the degradation of lignin. From the chemical standpoint, therefore, the selectivity of delignification is due to differences in the reactivity of the wood polymers, rather than to differences in the mechanisms of the degradation reactions. This fact explains the limitations of selective delignification.Parts of this work have been reported at the Fifth Planary Meeting of the International Academy of Wood Science on Copenhagen, Denmark, June 19, 1976, and at the ACS meetings in Appleton, Wisc., May 17–19, 1978, and Honolulu, Hawaii, April 1–6, 1979     

An interpretive view of refiner pulping

Summary Recent developments in refiner pulping are interpretively reviewed in terms of various aspects. These are the mode of chip breakdown, thermoplasticity, the influence of temperature on fiber breaks, torsion effects, physical state as a factor in the breakdown to coarse fiber bundles as well as fiber fraction characteristics, within fiber changes, observations on a hardwood, the introduction of chemicals, and future developments.The author is indebted to Mr. H. W. H. Jones for providing the prints used in Fig. 3, and to J. D. Hankey, R. G. Jamieson, and V. J. Van Drunen for their contributions.     

Effects of supercritical ammonia on bamboo pulping

We investigated the effects of supercritical ammonia on pulping of bamboo in a preliminary study,using testers such as differential scanning calorimetry(DSC),scanning electron microscopy(SEM),X-ray diffraction(XRD) and energy dispersive spectroscopy(EDS).The results indicate that under supercritical conditions at 185-190°C,it is possible for the ammonia to realize bamboo pulping.Compared with conventional kraft pulping,the products can meet the quality requirements of industrial paper.     

Characteristics of lignin obtained from steam-exploded softwood with soda/anthraquinone pulping

Lignins were obtained from a mixture of softwood sawdust using a hydrolytic pretreatment and a subsequent soda-anthraquinone delignification/pulping stage. Their potential uses and the effect of the pretreatment conditions on the yield (% of recovered lignin from black liquors) and chemical composition of isolated lignins were evaluated. The severity factor used combined the temperature and time of the hydrolytic process in a single ordinate (R_o). The severity range was modified from log R_o = 2.6 to log R_o = 4.6 and the pulping conditions were constant throughout the experiments. The effect of the cooking time on the chemical composition of precipitated lignins was also studied between 135–170 min for original (non-pretreated) material. Yield, elemental analysis, molecular weight distribution, Fourier transform infrared spectra (FTIR), structure, and the methoxyl and aliphatic/aromatic alcohol content of the various lignins, were compared.     

郑州市灵芝高产优质栽培技术

灵芝（Ganoderma lucidum）又称仙草、红芝、赤芝、丹芝、万年蕈等,在分类学上属于非褶菌目、灵芝菌科、灵芝属。灵芝对人体有益的成分有数千种,主要是甾醇类、三萜类、生物碱、多糖类、氨基酸多肽,此外,还有对人体有益的锌、锰、铁、锗等微量元素,     

桉树速生丰产栽培技术研究

根据桉树的生物学和生态学特性，结合泉州市多年来开展桉树引种试验结果，总结提出：适地适树、宜适种源；定向培育、合理密植；防治白蚁、栽前防治；细致整地、配施基肥；品系混造、精心栽植；除草抚育、追施肥料；间伐抚育、提高产量；道路设置、集约经营；森林防火、以防为主；二代更新、人工促进；实施标准、确保丰产等桉树速生丰产配套技术措施，以供大面积营造桉树提供参考。     

不同造林密度杨树速生丰产林成熟龄的研究

在不同密度欧美类杨速生丰产林生长规律的基础上,应用净现值方法对不同密度林分的经济成熟进行了分析。依据利润最大化的原则,确定不同密度林分的成熟龄;数量成熟龄和经济成熟龄随密度的增大而减小,林分经济成熟龄的时间是7~9 a(P=5.22%),数量成熟龄是12~14 a;对比其他密度,330株/hm2林分更适宜培育大径材;另外,对间作条件下的杨树速生丰产林的经济成熟龄与经济效益进行了分析。     

速生丰产林的产业地位和建设--以福建省光泽县饶坪经营所为例

以福建省光泽县饶坪经营所为例，阐述建设速生丰产林的重要性，提出速生丰产林建设中应注意的几个问题，并总结了经营所在速丰林建设中取得的经验和教训，为速生丰产林建设提供参考。     

邹平水杏及其丰产栽培技术

邹平水杏是邹平县林业局从邹平山区杏资源中选育出的一个优良的早熟杏品种 ,该品种 1987年在山东省杏鉴评会上 ,被评为优质杏第一名 ,列山东省林果志水杏之首 ,1998年获全国林果名优特新产品博览会金奖 ,并在国际风筝博览会上被指定为“蓝天杯”专用果品。邹平水杏畅销东北、华北、华东、台湾、香港等地 ,现种植面积已达 130 0ｈｍ2 。现将邹平水杏特性及栽培要点介绍如下 :1　品种特性1 1　果实经济性状果实近圆形 ,个大 ,平均单果重 89ｇ ,最大果重12 5ｇ。顶部圆或微凹 ,缝合线浅 ,两端中深 ,两半肉对称。梗凹狭 ,中深 ,果皮橘黄色 ,向阳…     

Geodatabase模型的版本控制原理及应用

地理空间数据模型设计是地理信息系统数据库建设的核心问题。本文介绍了GIS发展过程中出现的空间数据模型,以及不同空间数据模型的优缺点。并对Geodatabase版本控制原理进行了分析说明,提出了使用版本控制来管理空间数据库的多用户并发操作、长事务处理,从而保证空间数据库的完整一致性。     

桃形李引种与丰产栽培技术

桃形李为浙江省名优水果品种。安徽省青阳县以谨慎的科学态度 ,先少量引种观察其适宜生长、经济性状以及鲜果的质味 ,与原产地相比无异后 ,进行了大批量引种。在引种成功后总结出了其丰产栽培技术环节 ,包括肥水管理、树体管理以及防病治虫等     

冬枣优质丰产栽培技术

详细介绍了冬枣的优质丰产综合管理技术，包括壮苗的选育，整形修剪，土肥水管理以及提高座果率的措施等，可为大面积发展冬枣提供技术参考。     

翠冠梨的早期优质丰产栽培技术

翠冠梨是梨树的优良品种之一，扩大引种推广范围，实现早期优质丰产是生产上迫切需要解决的问题，经过5年试验取得了良好效果，该技术可供生产单位参考。     

桑木制浆性能的初步研究

研究了桑木的化学组成和纤维形态,并采用硫酸盐法和烧碱法对桑木的制浆性能进行摸索性试验.结果表明:桑木的木素含量为19.31%,综纤维素含量为78.31%,α纤维素含量为47.69%.纤维比量占69.50%,射线比量占16.31%,导管比量占14.19%.纤维平均长度为1 058 μm,长宽比为85.98,壁腔比为0.77.从纤维形态上看,桑木是一种较好的阔叶材造纸原料.两种方法比较,硫酸盐法比烧碱法更适合桑木的制浆.     

多穗石柯人工繁育及丰产栽培技术

多穗石柯为壳斗科石柯属常绿乔木,其叶片制作成甜菜产品,具有降血压、降血糖、降血脂、保肝降酶、抗过敏、抗衰老、增强免疫力等功效,市场开发前景广阔。多穗石柯为野生植物,自然状态下植株高大、散生,釆叶不便且产量有限,探索其人工繁育和矮化丰产栽培技术,在生产上具有重要意义。本文在工作实践的基础上,总结出多穗石柯有性和无性繁殖育苗、造林、人工林抚育培管、叶片釆收等技术方法和措施,可为多穗石柯人工驯化栽培提供技术参考。     

15个光皮树无性系早实丰产试验

15个光皮树无性系对比试验在湖南省龙山县可立坡林场和湖南省林业科学院试验林场进行。通过对15个无性系的生物性状和经济性状进行遗传测定、方差分析、主成分析和综合评分。结果表明：无性系早实性和丰产性受环境与遗传的作用存在着明显的差异;无性系主要性状遗传特性表现突出,尤其单株果穗数遗传力高达75．82％,单株鲜果产量遗传增益高达5．54％,无性系综合评分由高到低排序：G-15〉G-13〉G-5〉G—11〉G-14〉G-2〉G-1〉G-3〉G-10〉G-9〉G-12〉G-6〉G-8G-7〉G-4。     

Extraction of cellulose with subcritical and supercritical ethanol

lntroductionAsaresuItofthepublic'sincreasingenvironmentalawareness,theresearchesfocusedondevelopingprocessesthatutilizeIowtoxicorganicsoIventshavefIourishedinthepast1oyears.Mostofthesere-searcheshaveexaminedthepossibilityofusingsu-percriticaIandslightIysubcriticalfluidsaseXtractionandreactionsolvents(Reaves1999).SupercriticalfIuidextractionoflignoceIluIosicma-teriaIsfrombiomassissimilartopyrolysis,whichisusedtoconvertbiomasstousefuIchemicalsorfluidfuels(Goto199o).ThepyroIysisofbiomasscan…     

发展速生丰产林,促进平原绿化

论述了速生丰产林的发展前景 ,针对生产实践 ,提出了生产目标及类型选择的原则 ,在栽植管理上 ,提出了栽植方法、肥水管理、整理树形、防治病虫害、护林防火 5条技术意见 ,并对间作物问题作了分析。