木片浸渍程度数学模型的应用

采用木片浸渍程度数学模型对木片厚度、预汽蒸和添加表面活性剂等对木片浸渍程度的影响进行评价.结果表明,木片浸渍程度数学模型可用以评价各因素对木片浸渍程度的影响,是评价木片浸渍程度的一个有效工具.     

制浆过程中木片浸渍机理及改善措施

从木片浸渍的基本原理、评价手段和影响木片浸渍效果的因素等方面对木片的浸渍进行了阐述,并重点讨论了加强木片浸渍的措施。     

木片堆的管理

我厂长期以来一直采用露天大堆方式贮存木片 ,木片存贮质量影响制浆质量和生产成本。为了摸清木片堆湿度的变化情况 ,减少木片的腐朽 ,强化木片保管 ,我们对木片堆温度湿度的变化规律和木片堆的腐朽状况进行了测试。1　木片堆湿度变化木片含水率与材种、采伐季节、地区以及木片     

造纸木片的规格与特性

木片是制浆造纸工业的主要原材料。近年来国外发达的制浆造纸国家都在研究和制定木片规格,主要表现在以下方面: 1、木片规格。硫酸盐法制浆强调木片厚度。因为硫酸盐法蒸煮过程中,化学药液渗入木片的扩散速度在木材三个材面大致相同,所以临界规格最小的尺寸为即木片的厚度。如增加木片厚度将造成更乡的非均相蒸煮,筛渣增多。据介绍,最厚木片纸浆、比薄木片纸浆的木素含量高     

我国林区木片生产现状与对策

据东北林区消息,目前林区木片生产分为山上(伐木区)与山下(贮木、木材加工厂)两个系统。 一、林区木片生产的现状:山上木片生产分为带皮木片与剥皮木片两类。而且主要是以山下的带皮木片生产为主。 采用的木片加工工艺为: 枝丫材收集→挑选与整形→削片→筛选→木片贮运外销。     

广东木片生产的现状与对策

一、广东木片生产现状。 就全国木片生产而言,1994年全国生产木片300万绝干吨,而出口木片76.2万绝干吨。广东省94年生产木片41.8万绝干吨,其中雷州26.05万绝干吨,湛江14.88万绝干吨。全省出口木片37.5万绝干吨,创汇3140万美元。目前,木片已成为该省经济效益较好的产业。海外市场对木片需求量不断增加、例     

测定木片pH值的新方法

木片的风干或木片的储存是制浆造纸工厂通常采用的来减少木片中树脂的方法。这种处理方法的优点是减少引入生产中的木材树脂,进而减少在纸浆造纸过程中的树脂沉淀。然而,木片过长时间的储存会导致质量的恶化,如产生真菌污点、高酸度,木材发脆。当木片堆的温度达60~70℃时,木片就会发生化学反应,半纤维素分子中的乙酰基在反应中会断开,形成乙酸。这个反应产生热量并使木片的酸度增加;很明显,如果木片堆的热量不及时散发,就会加快该反应的速度。木片产生的酸通过降解纤维素分子链,导致了木片质量的恶化,这会造成木片制浆后强度和得率的损失。…     

商业木片的自动卸车——液压翻板的使用

随着造纸厂自削木片的大量减少,商业木片的采购量在急剧上升,汽车运输的商业木片卸车工作量也同时快速增长。由于木片是轻质松散物质,无法使用自卸汽车长途运输,因而木片卸车均使用大量人工劳动力。为了提高商业木片卸车效率,福建省青山纸业股份有限公司在关注木片自卸系统五年后,     

河北发展木片生产 向“三剩物”进军

木片广泛地使用于木浆及人造板生产。国内外历来很重视木片生产。据悉,美国不仅自用木片,每年出口木片735万m~3;加拿大出口木片145万m~3,芬兰出口木片24万m~3。贫林国家日本,每年进口木片1000万m~3以上。我国东北林业部门发展木片最快,牡丹江93年木片订货80万m~3之多。我国也出口木     

国产水洗系统的开发及应用

在中密度纤维板的生产中,清除木片中的杂质并使木片具有适当的含水率是一道重要的工序,该工序工作的好坏将直接影响到产品的质量及部分设备的使用寿命。木片经过筛选,虽然大块的木片及部分废渣被筛除,但合格木片中仍粘带有粉尘、泥沙、细小     

THE INSTITUTE OF BREWING ANALYSIS COMMITTEE: RECOMMENDED MICROBIOLOGICAL METHODS OF ANALYSIS

The Microbiology Sub-Committee of the Analysis Committee has recommended procedures for gram staining, establishing the level of total and bacterial contamination, for carrying out the lysine plating technique, for swabbing plant, for examining sugar syrups and wort syrups, for the examination of drinking glasses, for evaluating the sterility of beer containers and for performing the membrane filtration technique.     

Determination of several elements in duplicate meals from catering establishments using closed vessel microwave digestion with inductively coupled plasma mass spectrometry detection: estimation of daily dietary intake

An estimation of the dietary exposure of French consumers to 21 essential and non-essential mineral elements using duplicate meals (breakfast and lunch) purchased from catering establishments was investigated after digestion by a closed vessel microwave procedure and quantification by ICP-MS. Daily dietary exposure estimates for metals and minerals were compared with the Provisional Tolerable Weekly Intakes (PTWI), the Tolerable Daily Intake (TDI) or the Acceptable Daily Intakes (ADI), as established by the FAO/WHO to estimate the risk of toxicity, and the US Recommended Daily Allowances (US RDA) or the Estimate Safe & Adequate Daily Dietary Intakes (ESADDI). Moreover, comparisons were made with those from previous French studies as well as those from other countries. The estimated mean daily intakes were 11 μg for lithium, 3.42 g for sodium, 192 mg for magnesium, 2.03 mg for aluminium, 3.64 g for potassium, 642 mg for calcium, 154 μg for chromium, 12.3 mg for iron, 2.15 mg for manganese, 4 μg for cobalt, 74 μg for nickel, 925 μg for copper, 10.2 mg for zinc, 147 μg for arsenic, 66 μg for selenium, 112 μg for molybdenum, 3.6 μg for cadmium, 2.32 mg for tin, 3 μg for antimony, 9 μg for mercury and 34 μg for lead. For the non-essential (toxic) elements, aluminium, tin, antimony, cadmium, arsenic, mercury and lead, the daily intake estimates were far below tolerable limits; and similar or somewhat lower than their respective PTWI, ADI, TDI, ESADDI and US RDA for individual minerals and essential trace elements, with good agreement with other country studies. The performance of the multi-elemental ICP-MS technique was also evaluated.     

烤烟烘烤54度稳温时间对烟叶品质及效益的影响

通过对不同部位最佳采收成熟度烟叶54 ℃稳温时间的研究,分析了不同稳温处理与烟叶品质和可用性的关系。结果表明,变黄期采用“低温慢变黄”处理,上部叶54 ℃稳温16 h、中部叶稳温24 h、下部叶稳温8 h或16 h其致香前体物质含量较其他处理高;上部叶稳温16 h、中部叶稳温8 h或24 h、下部采收烟叶稳温16 h能获得较好的外观质量;下部适熟叶稳温16 h或24 h处理、中部采收烟叶稳温8 h处理、上部成熟烟叶稳温16 h处理物理特性较好;下部叶稳温8 h或16 h、中部叶稳温8 h、上部叶稳温16 h或24 h处理,香气质较细腻,吃味醇和,刺激性和劲头较小,余味较好。综合各处理烟叶品质,并结合经济性状分析表明,变黄期采用“低温慢变黄”处理,下部适熟烟叶54 ℃稳温16 h、中部成熟烟叶稳温8 h、上部成熟烟叶稳温16 h的处理,初烤烟叶能获得较好的综合品质和经济效益。     

Relationships between reproductive traits of heifers and cows and yield traits for Holsteins in Japan

The objective of this study was to investigate relationships between reproductive traits in heifers and cows and yield traits for Holsteins in Japan. Insemination and lactation records for cows calved between 1990 and 2003 in Hokkaido region were obtained. Age at first service, age at conception, and conception rate for first service were calculated for heifers. Days from calving to first service, days open, and conception rate for first service were calculated for first- and second-parity cows. The yield traits used were 305-d milk, fat, and protein yields. A threshold animal model was applied for the conception rate for first service, and a linear animal model was applied for the other traits. Single-trait and 2-trait genetic analyses were performed by the Bayesian method using Gibbs sampling. Heritability estimates ranged from 0.027 to 0.051 for conception rate for first service, and from 0.074 to 0.128 for the other reproductive traits. If the relationships of other traits were not considered, days from calving to first service was favorable to genetic selection for reproductive traits because of relatively high heritability and because it can be available earlier than the days open. Genetic correlations among reproductive traits were high, especially in cows. The genetic correlations between reproductive traits for heifers and those for cows were lower than the genetic correlations between reproductive traits for first parity and those of second parity, suggesting that reproductive traits for heifers should be evaluated separately from reproductive traits for cows. Genetic correlations between yield and reproductive traits in cows were antagonistic. In contrast, genetic correlations between reproductive traits for heifers and yield traits were slightly desirable. Depending on the reporting rate of insemination records for heifers and the results of investigations for relationships with productive maturity, selection by reproductive traits for heifers will enable the improvement of reproductive performance without a loss in genetic progress for yield traits.     

Determination of diuretics and laxatives as adulterants in herbal formulations for weight loss

A new method is described for the determination of the most common diuretic and laxative adulterants found in formulations of anorexics and antidepressants. The method is based on the separation of furosemide, hydrochlorothiazide, chlorthalidone and amiloride (diuretics), phenolphthalein (laxative), amfepramone (anorexic) and fluoxetine and paroxetine (antidepressants) by capillary zone electrophoresis with capacitively coupled contactless conductivity detection. The method showed a precision ranging from 1.9% to 6.9% for a concentration of 25 mg/L, 0.6% to 5.3% for a concentration of 50 mg/L and 1.6% to 6.0% for a concentration of 100 mg/L for all analytes. The accuracy was 99% for amiloride, 102% for chlorthalidone, 101% for hydrochlorothiazide, 101% for furosemide, 94% for phenolphthalein, 105% for fluoxetine, 114% for paroxetine and 117% for amfepramone. The method allowed the drugs to be determined in the formulations at concentrations higher than 5.1 mg/kg for amiloride, 7.7 mg/kg for chlorthalidone, 6.8 mg/kg for hydrochlorothiazide, 10.7 mg/kg for furosemide, 8.4 mg/kg for phenolphthalein, 11.0 mg/kg for fluoxetine, 9.4 mg/kg for paroxetine and 11.0 mg/kg for amfepramone. Three of the 26 analysed herbal formulations were found to be adulterated (not declared on the label) with the diuretic hydrochlorothiazide. Five other samples contained diuretics declared on the label on the formulation. Thus, a total of eight samples, which were marketed as natural products, contained diuretics (declared or not) on the formulation.     

不同海洋生物源肝素的理化性质及抗凝血活性

为研究和开发海洋生物源肝素,本实验采用酶解醇沉法从9?种海洋生物中提取出粗肝素,采用紫外光谱法、傅里叶变换红外光谱法和高效液相色谱法对其理化性质和结构特性进行分析,并通过体外凝血实验分析其抗凝血活性。结果表明：9?种肝素粗品的肝素含量从高到低依次为凡纳滨对虾（Penaeus vannaei）虾头339.92?μg/mg、海蚌（Mactra antiquata）239.15?μg/mg、泥蚶（Tegillarca granosa）234.85?μg/mg、蛏子（Sinonovacula constricta）218.29?μg/mg、文蛤（Meretrix meretrix L.）214.78?μg/mg、钝缀锦蛤（Tapes dorsatus）212.194?μg/mg、海湾扇贝（Argopecten irradias）68.52?μg/mg、象拔蚌（Panopea abrupta）61.48?μg/mg、菲律宾蛤蜊（Ruditapes philippinarum）24.29?μg/mg,其均为吡喃糖,且都含有肝素的主要单糖：氨基葡萄糖、艾杜糖醛酸和葡萄糖醛酸。体外凝血实验结果表明,9?种粗肝素效价从高到低依次为海蚌67.1?U/mg、凡纳滨对虾虾头59.3?U/mg、文蛤44.0?U/mg、钝缀锦蛤39.2?U/mg、蛏子35.0?U/mg、泥蚶29.6?U/mg、象拔蚌27.2?U/mg、海湾扇贝27.1?U/mg、菲律宾蛤蜊24.1?U/mg,它们具有不同强度的抗凝血活性,且发挥抗凝血作用的途径不同。实验结果可为海洋源肝素的开发提供参考。     

Dietary arsenic intakes in the United States: FDA Total Diet Study, September 1991-December 1996

The FDA has conducted the Total Dietary Study (TDS), a yearly market basket programme, since 1961. It is designed to monitor the levels of toxic chemical contaminants (pesticide residues, industrial and elemental contaminants) and essential nutrients in the US food supply. It also provides information on trends in dietary concentrations and exposures for the general population. Foods are collected from retail stores once a year from each of four geographic areas of the US and are analysed either after preparation/cooking or as ready-to-eat. The latest TDS (1991-1997) data show that arsenic (inorganic and organic, ≥ 0.03ppm) was found in 63 (24%) of the 261-264 foods/mixed dishes analysed. The highest concentration was found in seafood, followed by rice/rice cereal, mushrooms, and poultry. Based on the United States Department of Agriculture's 1987-1988 Nationwide Food Consumption Survey, the estimated daily total arsenic average intakes, in mu g/day, are: 2 for infants, 23 for toddlers, 20 for 6-year-old children, 13 for 10-yearold children, 15 for 14-16-year-old boys, 21 for 14-16-year-old girls, 57 for 25-30-year-old men, 28 for 25-30-year-old women, 47 for 40-45-year-old men, 37 for 40-45-year-old women, 92 for 60-65-year-old men, 72 for 60-65-year-old women, 69 for 70-year-old men, and 42 for 70-year-old women. Of the estimated total arsenic intakes for infants, 42% arise from seafood and 31% from rice/rice cereals. Of the estimated total arsenic intakes, seafood contributes 76-90% for children (2-10-year olds), 79-85% for 14-16-year olds, and 89-96% for adults (≥ 25-30-year olds); rice/rice cereals contributes 4-8% for children, 8% for 14-16-year olds, and 1-4% for adults (≥ 25-30-year olds).     

Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States

Use of sexed semen for artificial insemination of US Holstein heifers (1.3 million breedings) and cows (10.8 million breedings) in Dairy Herd Improvement herds was characterized by breeding year, parity, service number, region, herd size, and herd milk yield. Sexed semen was used for 1.4, 9.5, and 17.8% of all reported breedings for 2006, 2007, and 2008, respectively, for heifers, and for 0.1, 0.2, and 0.4%, respectively, for cows. For 2008 sexed semen breedings, 80.5 and 68.6% of use was for first services of heifers and cows, respectively. For cows, 63.1% of 2008 sexed semen use was for first parity. Mean sexed semen use within herd was the greatest for heifers in the Southwest (36.2%) and for cows in the Mideast (1.3%). Mean sexed semen use increased for heifers but changed little for cows as either herd size or herd mean milk yield increased. Availability of sexed semen was examined for Holstein bulls in active AI service; of 700 bulls born after 1993, 37% had sexed semen marketed by mid August 2009. Active AI bulls with marketed sexed semen were superior to average active AI bulls for evaluations of yield traits, productive life, somatic cell score, daughter pregnancy rate, service-sire calving ease, service-sire stillbirth, final score, sire conception rate, and lifetime net merit. The effect of sexed semen use on conception rate, calf sex, dystocia, and stillbirth also was examined for heifers and cows. Mean conception rate for heifers was 56% for conventional and 39% for sexed semen; corresponding conception rates for cows were 30 and 25%. For single births from sexed semen breedings, around 90% were female. Dystocia and stillbirth were more frequent for heifers (6.0 and 10.4%, respectively, for conventional semen; 4.3 and 11.3%, respectively, for sexed semen) than for cows (2.5 and 3.6%, respectively, for conventional semen; 0.9 and 2.7%, respectively, for sexed semen). Difficult births declined by 28% for heifers and 64% for cows with sexed semen use. Stillbirths were more prevalent for twin births except for sexed semen heifer breedings. Stillbirths of single male calves of heifers were more frequent for breedings with sexed semen (15.6%) than conventional semen (10.8%); a comparable difference was not observed for cows, for which stillbirth frequency of single male calves even decreased (2.6 vs. 3.6%). Overall stillbirth frequency was reduced by sexed semen use for cows but not for heifers.     

大黑粉盗与赤拟谷盗和锈赤扁谷盗对磷化氢的耐受力比较研究

潜在危害的储粮害虫大黑粉盗Cynaeus angustus研究缺乏,掌握其磷化氢耐受力有助于科学治理。采用快速击倒和FAO推荐方法测定了磷化氢对大黑粉盗的KT50值和毒力方程,并与赤拟谷盗Tribolium castaneum和锈赤扁谷盗Cryptolestes ferrugineus进行了比较,测定了100、200、300、400、500 mL/m3磷化氢模拟熏蒸中3种害虫卵、幼虫、蛹和成虫不同时间的死亡率。磷化氢对大黑粉盗、赤拟谷盗和锈赤扁谷盗的KT50值分别为7、127和3 736 min,相应毒力方程斜率值b为3.67、8.28和9.94,相应LC50值为0.008、1.34和5.88 mg/L。害虫不同虫态在100~500 mL/m3浓度下的半数致死时间LT50值于大黑粉盗卵为4~2 h、幼虫4~1 h、蛹4~1 h、成虫3~1 h,于赤拟谷盗为卵12~5 d、幼虫11~5 d、蛹13~7 d、成虫10~4 d,于锈赤扁谷盗为卵28~13 d、幼虫为18～9 d,蛹26～11 d,成虫17~9 d。相应的完全致死时间（LT100）于大黑粉盗卵为21~6 h、幼虫8~3 h、蛹9~6 h、成虫5~3 h,于赤拟谷盗卵为21~18 d、幼虫21~15 d、蛹27~18 d、成虫21~12 d,于锈赤扁谷盗卵为54~30 d、幼虫42~30 d、蛹48~30 d、成虫36~25 d。所测大黑粉盗为磷化氢敏感品系,其各虫态对磷化氢的耐受力为卵>蛹>幼虫>成虫,其耐受力远小于赤拟谷盗和锈赤扁谷盗磷化氢抗性品系。     

Assessment of dietary exposure to annatto (E160b), nitrites (E249-250), sulphites (E220-228) and tartaric acid (E334) in the French population: the second French total diet study

The results of the assessment of the dietary exposure to annatto, nitrites, tartaric acid and sulphites within the framework of the second French total diet study (TDS) are reported. These 4 additives were selected from the Bemrah et al. study [Bemrah N, Leblanc JC, Volatier JL. 2008. Assessment of dietary exposure in the French population to 13 selected food colours, preservatives, antioxidants, stabilizers, emulsifiers and sweeteners. Food Addit Contam B. 1(1):2–14] on 13 food additives which identified a possible health risk for annatto, sulphites and nitrites and a lack of data for tartaric acid. Among the composite samples selected for the whole TDS, 524 were analysed for additives (a sample was analysed for a given additive when it was identified as a major contributor for this additive only): 130 for tartaric acid, 135 for nitrites, 59 for annatto and 200 for sulphites. Estimated concentrations (minimum lower bound to maximum upper bound) vary nationally from 0 to 9?mg/kg for annatto, 0 to 420?mg/kg for tartaric acid, 0 to 108?mg/kg for sulphites and 0 to 3.4?mg/kg for nitrites. Based on the analytical results, the dietary exposure was calculated for adults and children, separately, using lower bound and upper bound assumptions. The European ADIs for these 4 additives were not exceeded except for the dietary exposure for sulphites among 2.9% of the adult population, where the major contributors were alcoholic drinks and especially wine under both hypotheses (lower and upper bound).