迷迭香提取物检测方法研究进展

介绍了迷迭香提取物的种类,综述了迷迭香提取物的分析测定方法,主要包括高效液相色谱法、胶束电动色谱法、紫外光谱分析法、红外光谱分析法、毛细管电泳法、气相色谱法、质谱法、核磁共振波谱法等,并比较了各种方法在使用上的差别.     

杨树杂交的两种新技术

介绍了杨树杂交的两种新技术:室外大树侧倒法和室外切枝扦插法.新技术具有高效、经济、安全等优点,在杨树杂交育种以及其他易生根乔木杂交育种中具有应用价值.     

匀浆法提取沙棘果中总黄酮的工艺研究

为了建立一种高效提取沙棘果中总黄酮的方法,对匀浆法提取沙棘果中总黄酮的工艺进行了研究,确定了最佳的工艺参数:提取原料为含水率85%的沙棘果,溶剂为85%的乙醇,匀浆时间10 m in,液固比为5∶1(mL∶g)。将该法与常规的回流提取法进行了比较。结果表明,在优化的条件下,匀浆法对沙棘果总黄酮的提取率为0.76%,与回流提取相当。匀浆提取法所用提取时间短,提取溶剂用量少,该法是一种高效、快速提取沙棘果总黄酮的方法。     

退耕还林地块面积量测方法研究

本文通过对带镜罗盘仪导线绕测法、GPS导线绕测法、GIS勾绘法3种面积测量方法,在我省新一轮退耕还林不同地类小班进行实测比对,提出了选择更加高效便捷面积量测的方法。     

以切板法利用小径材的探讨

切板法是高效利用小径材的途径之一。本文阐述了切板法的特点和工艺，以及以切板法为基础利用小径材作原料的几种典型产品包括卫生筷、胶合地板块、胶拼装饰板的生产工艺。     

微波无溶剂法提取樟叶精油

用无溶剂微波萃取法(SFME)提取樟树叶精油,并与传统水蒸气蒸馏法(HD)进行对比,考察了微波功率和萃取时间对产物产率和组成的影响。采用SEM对不同方法提取前后的叶片结构进行表征。结果表明:在最佳提取功率500W下,使用SFME法提取35min与使用HD法提取5h得到的精油的得油率和芳香分布均较为相似,最终得油率分别为0.98%和0.96%,但SFME法在高效、节能和清洁方面优于HD法。GC-MS分析结果可以看出,SFME法得到的提取物中含氧化合物总量为75.54%,明显高于HD法的62.12%。此提取技术具有快速高效、能耗低、不需要外加水和溶剂等优点,是一种新型、绿色的提取技术。     

鹿蹄草内生真菌的生物学特性的研究

对不同季节、不同地区的野生鹿蹄草进行采样,采用表面消毒法及内生真菌选择性培养基,分离菌根中的内生真菌,并通过回接实验筛选能显著促进鹿蹄草生长的高效菌株;通过改变培养时间、培养温度、pH、碳源、氮源等环境条件,研究高效菌株的生物学特性。     

家庭储粮杀虫新技术

现介绍一种安全、高效、经济、简便的杀虫新技术——磷化锌加食醋熏蒸法。该法既适用于农户储粮杀虫,也适用于城镇居民家庭储粮杀虫之用。该法的具体操作是:用碗或罐头瓶装上酸醋水(醋和水的比     

超声波辅助法提取马兰总黄酮的研究

用70%乙醇为浸提剂,采用超声波辅助法从马兰地上部分提取总黄酮,并通过比色法测定其含量。结果表明,超声波辅助法提取马兰地上部分总黄酮含量为12.75%,提取效率是普通回流提取法的1.625倍,说明超声波辅助法具有省时、高效、节能等特点,是提取马兰总黄酮的有效方法。     

正交试验对喜树碱提取工艺的筛选研究

以喜树碱提取率为指标，应用高效液相色谱定量分析，比较乙醇超声法、乙醇热浸法、乙醇索氏法、碱法、NaOH超声法等5种提取方法，筛选出高提取率的方法——乙醇超声法。并通过正交试验设计优选出喜树碱的提取工艺条件：乙醇浓度60％、乙醇用量14m魄、超声时间120s、超声提取1次。     

Analysis of the factors influencing the acetylation rate of wood

Factors influencing the rate of acetylation were examined based on the swelling of wood in the reaction solution and the dimensions of the wood sample. The activation energy of acetylation was also estimated. In a swelling test, it was found that wood swells thoroughly in acetic anhydride even without pyridine above 60°C. Therefore, pyridine may facilitate the acetylation process as a catalyst and not as a swelling agent. The weight gain, x (%), attained at reaction time t (h), for various compositions of acetylation solution or dimensions of wood sample were analyzed by applying an original rate equation [x = a × (1 – e^–kt )^1/n ], where a is the ultimate weight gain (%), k is the rate constant (h^–1), and n is a measure of the hindrance against the diffusion of reagent. The optimum volume fraction of pyridine in the pyridine-catalyzed acetylation was about 0.2. Accompanied by a rise in pyridine content, the reaction showed increased diffusion-controlled behavior. The rate constant, which is not affected by the dimensions of the wood sample, was estimated from which an activation energy of about 130kJ/mol was calculated.     

Role of the gelatinous layer (G-layer) on the origin of the physical properties of the tension wood of Acer sieboldianum

The tension wood (TW) properties of a 70-year-old specimen of Acer sieboldianum Miq. were analyzed by using the G-fiber model that was proposed in our previous report. The roles of the G-layer on the origins of (1) a high tensile growth stress, (2) a large longitudinal Young’s modulus, and (3) a high longitudinal drying shrinkage in the TW xylem are discussed on the basis of the simulations using the G-fiber model. The results suggest that the G-layer generates a high tensile stress in the longitudinal direction during xylem maturation; the longitudinal Young’s modulus of the green G-layer becomes significantly higher than that of the lignified layer; furthermore, the G-layer tends to shrink extraordinarily more than that of the lignified layer during moisture desorption.This report follows the previous report “Role of the gelatinous layer on the origin of the physical properties of the tension wood.” J Wood Sci (2004) 50:197–208. Part of this paper was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999, and at the 2nd International Conference of the European Society for Wood Mechanics, Stockholm, May 2003This revised version was published online in July 2005. On pages 228–230 the character was replaced by a vertical line.     

On the effect of the loading time on the strength properties of wood

Summary One of the most important tasks of wood engineering concerning the determination of permissible stresses in the design of wooden structural parts is to take into consideration the influence of the duration of loading on the strength properties of structural timber.On this subject a number of investigations were carried out and published in Japan. Most of the publications, however, were written in Japanese and were published in Japan only. In consequence, practically no access was gained to the international literature in this field.The present paper intends to give a summary report of the above results. They were deseribed more in detail by the author in a book written in Japanese.

---

Zusammenfassung Die Einbeziehung des Einflusses der Belastungsdauer auf die Festigkeitseigenschaften von Bauholz gehört zu den wichtigsten Aufgaben des Holzbau-Ingenieurs, wenn er sich mit der Frage der zulässigen Spannungen beim Entwurf von Holzbaukonstruktionen beschäftigen muß.Zu dieser Frage wurden in Japan eine Reihe von Untersuchungen durchgeführt und veröffentlicht. Die überwiegende Zahl dieser Arbeiten wurde jedoch in japanischer Sprache verfaßt und deshalb ausschließlich in Japan publiziert. Sie fanden deshalb so gut wie keinen Eingang in das internationale Schrifttum dieses Fachgebietes.Die vorliegende Arbeit soll zusammenfassend hierüber berichten. In ausführlicher Form wurden die dargestellten Ergebnisse vom Verfasser in Buchform, in japanischer Sprache veröffentlicht.

     

Effect of the lectin PHA on the feeding behavior of the grain aphid

The electrical penetration graph (EPG) method was used to quantify the effect of the lectin PHA (phytohemagglutinin) on the feeding behavior of the grain aphid Sitobion avenae F (Hemiptera: Aphididae). Addition of PHA to an artificial diet affected aphid probing behavior. In general, increasing concentrations of PHA in sucrose-agarose gels significantly reduced the number of aphid probes and extended their duration. Aphids feeding on the gels with lectin (without concentration 50 μg · cm⁻³) had a prolonged activity (EPG pattern C) that was corresponded to prolonged penetration of the epidermis and mesophyll for aphids feeding on plants. Such insects also showed a significant reduction in salivation and passive ingestion from gels and a reduction in the total number of gel penetrations. At concentrations ≤250 μg · cm⁻³, PHA reduced feeding behavior on gels, and the EPG data were interpreted to correspond with reduced salivation into phloem sieve elements (EPG pattern E1) and reduced ingestion of phloem sap (EPG pattern E2). PHA also delayed the onset of the first E1 and E2 patterns. At higher concentrations (≥500 μg · cm⁻³), PHA completely stopped salivation and passive ingestion from gels. Similarly, higher concentration of PHA strongly reduced activity on gels that corresponded to activity in xylem (EPG pattern G); high PHA delayed the onset of the first G pattern and reduced total time of pattern G activity.     

On the distribution of the diastereomers of the structural elements in lignins: the steric course of reactions mimicking lignin biosynthesis

Summary Stereochemical studies on the formation of the diastereomers of arylglycerol--aryl ether structures during lignin biosynthesis have been carried out with model compounds. The addition of water to quinone methides of the -syringyl ether type gives arylglycerol -syringyl ethers with a predominance of the erythro isomer when the pH of the medium is low. Since erythro forms of arylglycerol -syringyl ethers are prevalent in hardwood lignins, this indicates that the pH of the medium in which lignin biosynthesis occurs is lower than has been assumed until now. Equilibration studies with non-phenolic model compounds of the arylglycerol-guaiacyl ether and -syringyl ether types under acidolysis conditions indicate that the erythro predominance observed in the syringyl ethers in lignins does not correspond to equilibrium conditions. A remarkable resistance to acidolysis is observed in the model compounds of etherified syringylglycerol -syringyl ether type.     

Applicability of the losipescu shear test on the measurement of the shear properties of wood

We examined the applicability of the Iosipescu shear test for measuring the shear properties of wood. Quarter-sawn board of sitka spruce (Picea sitchensis Carr.) and shioji (Japanese ash,Fraxinus spaethiana Lingelsh. were used for the specimens. Iosipescu shear tests were conducted with two types of specimen whose longitudinal and radial directions coincided with the loading direction. The shear modulus, yield shear stress, and shear strength were obtained and were compared with those obtained by the torsion tests of rectangular bars. The results are summarized as follows: (1) The Iosipescu shear test is effective in measuring the shear modulus and the yield shear stress. (2) To measure the shear strength properly by the Iosipescu shear test, the configuration of specimen and the supporting condition should be examined in more in detail.     

On the constitutive equations of the orthotropic theory of creep

Summary Creep equations have been formulated for the multi-axial state of stress for an orthotropic medium, based on an invariant proposed by Hill for theory of plasticity. Anyone of the numerous creep laws suggested from time to time by different investigators on the basis of experiments can then be used in these equations giving a complete set of equations for the solution of creep problems in orthotropic medium. Two simple applications are also discussed. An example in which principal axes of stress do not coincide with axes of anisotropy tension of a bar is discussed. Another example, that of compression under conditions of plane strain, illustrates variation of stress with time although load is kept constant. It is shown that in this case {ie142-1} relaxes to the final value {ie142-2} after a few times the retardation time.

---

Zusammenfassung Gleichungen zur Berechnung von Kriechdehnungen wurden für den mehrachsigen Spannungszustand orthotroper Stoffe aufgestellt, deren Grundlage eine von Hill für die Plastizitätstheorie vorgeschlagene Konstante bildet. Jedes der zahlreichen Kriechgesetze, die von verschiedenen Autoren auf Grund von Versuchen immer wieder vorgeschlagen wurden, kann mit Hilfe dieser Gleichungen Anwendung finden und bildet ein vollständiges Gleichungs-system zur Lösung von Kriechproblemen in orthotropen Stoffen. Desgleichen werden zwei einfache Anwendungsmöglichkeiten erörtert. Ein Beispiel wird dargestellt, in welchem die Haupt-Spannungsachsen nicht mit den Achsen der anisotropen Zugspannung in einem Balken zusammenfallen. Ein weiteres Beispiel mit Druckbelastung veranschaulicht bei Annahme einer ebenen Dehnung die Änderungen des Spannungszustandes mit der Zeit, wenn die Belastung konstant bleibt. Es wird gezeigt, daß sich in diesem Fall {ie142-3} bis zu dem Endwert {ie142-4} ermäßigt nach einer Zeit, die einem Mehrfachen der Retardierungszeit entspricht.

---

---

The second author gratefully aknowledges the grant of a C.S.I.R. fellowship.     

Some Aspects of the Growth and Spread of Fire in the Open

This paper describes some recent experimental and theoreticalwork on the growth and spread of fire in the open and discussessome examples of field data in terms of the theoretical calculationspresented. The lengths of flames from laboratory fires have been relatedto the size and rate of burning of the fuel by formulae derivedfrom a simplified dimensional analysis. The effects of a windblowing across a long fuel bed on the length and orientationof flames are also described. The scaling laws for flame heightsuggest that in the horizontal spread of fire, heat transferfrom the flames above the fuel bed is important primarily withshallow fuel beds. It is suggested that the main effect of a wind on crib firesis aerodynamic. The wind deflects the advancing fire front fromthe vertical, but perpendicular to this deflected front therate of spread of fire, at least for cribs, is roughly the sameas in still air. However, a theory of spread allowing for heattransfer through the fuel bed and radiation from the flamespredicts that there can be a stable ‘fast‘ spreadas well as a ‘slow’ spread. In ‘fast’spread the flames are thick and control the spread. In ‘slow’ spread radiant heat transfer from theburning zone is usually responsible for the spread. The flamesare thin and of low emissivity. The most important factors determiningthe rate of ‘slow’ spread R are ^pb the bulk densityof the fuel bed and ø the deflection from the verticalof the front of burning fuel which varies with wind speed. Rpb cos ø is approximately constant over a wide rangeof conditions with an order of magnitude of 5–10 mg cm^–2s^–1.     

外力作用下4种植物根系易损部位的研究

[目的]为探讨根系在轴向拉力和径向折力下的易损部位。[方法]以3 4 a的柠条、沙柳、沙棘和白沙蒿为研究对象,采用TY8000伺服控制材料试验机测定4种植物侧根分支处和相邻直根的抗拉力与抗折力。[结果]表明:在1 4 mm根径范围内,4种植物侧根分支处和相邻直根的抗拉力、抗折力均与直径呈幂函数正相关,抗拉强度、抗折强度均与直径呈幂函数负相关;同径级时,每种植物单根的抗拉强度和抗折强度均表现为侧根分支处小于相邻直根,4种植物侧根分支处和相邻直根的抗拉强度为柠条((23.70±3.97)、(28.02±4.40)MPa)沙柳((14.86±1.28)、(20.33±1.76)MPa)沙棘((10.60±2.40)、(15.86±3.90)MPa)白沙蒿((5.07±1.25)、(8.80±1.74)MPa),侧根分支处和相邻直根的抗折强度为:柠条((33.66±7.74)、(47.06±4.41)MPa)沙柳((17.31±1.91)、(27.54±3.82)MPa)沙棘((3.97±1.23)、(8.75±1.70)MPa)白沙蒿((2.18±0.39)、(6.15±1.01)MPa)。[结论]无论受轴向拉力还是径向折力,4种植物根系易损部位均为侧根分支处。造成垂直根模型(WWM)和纤维束模型(FBM)预测根系固土能力偏高的补充原因为:(1)模型根系全部计入直根的抗拉力,忽略了侧根分支处,而侧根分支处是根系固土的薄弱点。(2)模型假设所有根系为轴向受拉的杆件。实际根土复合体发生剪切时,根可能承受轴向拉力,也可能承受径向折力。对于抗折强度小于抗拉强度的植物,模型必然高估根的实际固土能力。