Extraction and antioxidant activity of collagen from elephant skin, pig skin and fish scales

目的:研究传统中药象皮和拟替代品猪皮、鱼鳞的胶原结构和抗氧化活性.方法:通过正交试验设计法,优选了象皮胶原的最佳提取条件,与拟替代品胶原对其结构和含量进行比较,采用水杨酸法测定其各自清除羟基自由基能力.结果:首次从象皮中提取了结构完整且质量较多的胶原,与拟替代品的胶原结构类型相似,其象皮胶原、猪皮胶原、鱼鳞胶原清除自由基能力衡量值IC5o分别为0.51,0.60,0.42g·L-1.结论:通过比较和鉴定,象皮胶原蛋白为Ⅰ型胶原,抗氧化能力较强,明确了象皮的有效成分,为今后进一步探讨象皮替代品研究提供了重要参考依据.     

振荡提取/超声提取-红外分光光度法测定城市污泥中石油类

本试验以四氯乙烯代替四氯化碳,以振荡提取、超声提取代替索氏提取法提取城市污泥中的石油类,并对振荡频率、提取时间等条件进行了研究.结果表明,当取样量为1 g时,采用振荡提取法,振荡频率150 r/min、提取时间60 min为最佳试验条件;采用超声提取法,超声频率40 Hz、提取时间60 min为最佳试验条件.     

红枣色素提取工艺实验研究

实验选用溶剂提取法从红枣中提取其色素成分,主要研究了从红枣中提取色素的工艺条件.结果表明:红枣色素在300 nm处有最大吸收波长.红枣色素提取的最佳工艺条件为:将红枣在90℃烘干5h得到的枣粉,用1.5％的NaOH,80℃提取80 min时溶液吸光度值最高.影响浸提效果的因素主次顺序为温度＞时间＞溶剂浓度.     

商业银行微贷业务信用风险评估浅探

本文选取系列定量指标，利用主成分分析法进行分析和提取主成分．计算企业的综合信用得分。计量结果袁明．小微企业的短期偿债能力和现金流水平对信用风险评估影响显著。银行得到信用评分后，可自行设定标准分类，做出判断。     

从氧化铝载体的废钯催化剂中回收钯的工艺研究及生产技术新突破

本研究借助传统的从三氧化二铝为载体的废钯催化剂中提取钯的工艺．确认了试验及生产中的技术条件．并在精提中筛选出了还原剂，使用了代号为A的络合剂，很好地解决了精提工艺中钯铝分离的技术难题，而使回收钯的工艺取得了技术性的突破。     

肉制品中牛源性成分的快速定性检测研究

文章通过选用磁珠法组织核酸提取试剂盒对畜肉制品中的DNA进行提取,使之适用于PCR检测技术,依据标准《畜肉制品中牛成分定性检测方法实时荧光PCR法》(SN/T 2557—2010)检测其中是否含有牛特异性基因序列,同时在提取时加入猪源作为干扰,并进行灵敏度试验,为验证提取、扩增过程及方法准确性,加做核酸提取空白、扩增空白对照、扩增阴性对照和扩增阳性对照。该方法选用的磁珠法组织核酸提取试剂盒提取效率高,抗干扰能力强,且该方法在检测结果分析中增加了质量控制,可排除假阴性结果,检测时间可缩短为4 h以内,可用于市售新鲜、冷冻畜肉和肉干、肉酱等畜肉制品中的牛成分快速定性检测。从而为打击不法商家和企业用低价猪肉代替或非肉冒充牛肉提供了有力的技术保障,维护了消费者权益。     

超声波协同酶法提取银杏黄酮的工艺研究

研究了超声波协同酶法提取银杏黄酮的最佳工艺条件,以总黄酮得率为考察指标,研究了加酶量、pH值、液固比、超声波功率、酶解时间和温度等因素对银杏黄酮得率的影响,并在单因素的基础上通过正交试验对提取工艺条件进行了优化。结果表明:最佳提取工艺条件为加酶量1 mg/g,pH值4.5,液固比10∶1(mL/g),超声功率240 W,时间80 min和温度45℃,此时总黄酮的得率为2.78%。     

美国车辆尾气成为新水源

美国军方正在试验野外条件下获得饮用的新型设备。令人难以置信的是,饮用水竟是车辆排放的废气中提取的。哈密尔顿—桑特兰司研制的这种装置可以将汽车燃油中含有的分提取出来。其工作原理就是对发动机气休混排放物中的氢成分进行氧化。但该装置所采用设备同样令人闻所末闻,整套生水器包括再生换热器、蒸发器、抽水机和过滤器。一套生水器价值约2.5万美元。发动机排放的废气进入再生式换热器,冷却达到一定温度,水汽开始冷凝。然后对水进行消毒,并加入盐,使水更接近自然味道。在Humvee吉普车上进行的试验表明,1小时内可从2加仑燃油中提取1加…     

用木屑提取柴油

日本发明了一种用木屑提取柴油的方法:在木屑中掺入碳酸钾等触媒物质之后,加入水、醋酸等物质,然后在20个大气压、300℃的条件下提取柴油。据称,用这种办法可以从5克木屑中提取3克柴油。提取的柴油呈黑褐色,在成分上     

丹参注射液药渣再提取丹参酮Ⅱ_A工艺的研究

文章主要介绍了经过水提醇沉工艺提取丹参注射液的药渣,再提取丹参酮ⅡA工艺研究。采用正交试验法,以丹参酮ⅡA的提取量及收率为考察指标,优选回流法提取的最佳工艺条件,从而提高丹参的综合利用价值。     

重估人民币汇率升值对中国经济的影响——基于2005年汇改以来的经验证据

反思人民币汇率十年争论,大多围绕"外部施压——内部被动反应"的逻辑展开,人民币汇率陷入升值"恐惧症"。本文以经验数据实证分析人民币汇率各种争论的理论逻辑。研究表明,人民币升值并没有导致通货紧缩,人民币升值也没有促使就业下降,相反,人民币升值还伴随经济过热及就业持续增加;同时,人民币升值无助于改善国际收支平衡和贸易条件、人民币升值引起热钱流入的观点都缺乏经验的支持。因而,人民币升值"恐惧症"的理论逻辑值得重新审视,中国开放宏观政策选择有必要跳出被动应对怪圈,这对促进当前中国经济结构调整及可持续发展的政策选择具有重要意义。     

新型再生橡胶性能研究

本试验根据硫化胶的再生理论、橡胶补强理论、橡胶共混相容性理论开展研究。优化了配方、工艺条件、生产设备,创新性提出了新型再生橡胶及制作方法,并制作出了高品质再生橡胶。生产过程无污t染、能耗低、自动化程度高。制作的再生橡胶与天然橡胶等原胶共混后,胶料性能不降低。甚至某些性能比原胶胶料还要好。     

需求突变下的供应链应急管理研究

突发事件是导致供应链需求突变的一个重要因素.文章从风险管理的视角,构建了供应链需求突变应急管理模型,采用计算实验方法探讨供应链需求突变应急管理机制.实验结果表明,在需求突变周期内,多个企业在同一个市场条件下均进行需求管理,可能会引起对市场的过度反应,带来整体利润的降低,因此零售商应该与制造商进行信息共享,由制造商主导联合决策,制定统一管理方案,才能更好应对需求突变带来的影响.     

Implications of Exchange Rate Pass-Through and Nontradable Goods for International Policy Cooperation

This paper investigates the welfare consequences of international policy cooperation by simultaneously introducing the following three elements in a standard two-country general equilibrium model: (i) general degrees of exchange rate pass-through, (ii) nontradable goods and their sector-specific productivity shocks, and (iii) general weights on goods in Cobb–Douglas consumption indices. There are two channels for possible mutual welfare gains from policy cooperation: First, cooperation can compensate for insufficient changes in the terms of trade when the degree of exchange rate pass-through is intermediate. Second, countries can cooperate in reaction to shocks in the nontradable goods sectors. This second channel is revealed by deriving an analytical condition for welfare gains under full pass-through and this condition is characterized by the weights in the consumption indices and the variances of sector-specific productivity shocks. Numerical evaluation demonstrates that when the two countries are symmetric and equal weights on consumption goods are assumed, welfare gains from cooperation increase as symmetric pass-through elasticity increases, which implies that the second channel dominates the first, whose effect on welfare gains is nonmonotonic in pass-through elasticity.     

The economics of golf course condition and beauty

This paper reports on the statistical relationships between golf course condition and beauty and the relationship of these with revenues and maintenance expenditures. Using interviews from more than 900 golfers at 46 public access golf courses, measures of the golfers' ratings of golf course condition and beauty were obtained. Both beauty and condition positively influence golf course revenue. Furthermore, the marginal cost of condition is of the same magnitude as the marginal revenue of condition, indicating that golf course management is optimizing regarding golf course condition. Beauty, however, may be more closely related to scenic vistas and golf course design and not to yearly maintenance expenditures.     

Fiscal Sustainability of Local Governments in Japan†

The total amount of Japan's local government (LG) expenditures exceeds its central government (CG) expenditures. Japan's LG and CG are responsible for the worst general government's debt situation among the G7 countries. The paper elucidated the fiscal reactions of Japan's prefecture governments (PGs) based on Bohn's (1998a, 2005) method with a panel dataset (44PGs, fiscal years 1974–2016), addressing nonstationary and endogeneity issues. In my model, a positive reaction of the primary surplus/gross regional product (GRP) ratio to the PG debt/GRP ratio (d) constitutes a sufficient condition for sustainability. The results of the study demonstrate the following: (i) the PG in any fiscal condition are assumed to provide sustainable fiscal management; (ii) the PGs in sounder or more dire fiscal conditions probably manage their finances more firmly; (iii) the fiscal transfers from the CG generally ease the PG fiscal conditions; (iv) although primary regressors d and dsq (the square of d) are assumed to be I (1) with some accuracy, they become stationary through cointegration with other regressors.     

中国地方政府债务违约风险评估——基于债务可持续性分析框架

结合中国地方政府财政反应特征,文章在债务可持续性分析框架中,首次识别了基础盈余主动调整的有效性条件作为分析前提,进而完善了债务不可持续性的定义内涵和度量方法,最终建立了地方政府债务违约风险评估模型。凭借此模型,对中国地方政府债务违约风险进行了评估,主要结论如下：在经济增速不稳定背景下,施行顺周期财政政策的中国地方政府,容易落入基础盈余主动调整无效的境况,因而在对地方政府债务可持续性进行分析时,有必要考虑基础盈余主动调整的有效性;通过检验发现,新构造的债务不可持续概率和条件期望债务空间指标,均能较好反映地方政府债务违约风险,而单纯的债务率指标对地方政府债务违约风险无解释力;在2019年,天津、贵州和青海等地已处于财政疲劳引起的债务不可持续状态,内蒙古等六省的条件期望债务空间不足20%,其余省份的条件期望债务空间仍相对充裕;最后,通过考察债务可持续性的改善渠道又进一步发现,财政透明度的提高可有效降低地方政府债务违约风险。     

硫脲法从电镀污泥中提金工艺研究

研究了酸性硫脲溶液从电镀污泥中浸提金的方法.通过考察多种因素对浸金效果的影响,确定了最佳浸提条件:在拟定的浸提条件下浸提4次,可以使电镀污泥中金的浸出率达91.0%.     

含油石化废催化剂低压脱油预处理研究

采用低压脱油的方法对含油石化废催化剂进行预处理研究,分别考察了温度、压力、保温时间、升温速率等条件对低压脱油过程的影响,确定低压脱油的最佳实验条件:加热终温550℃;压力2×104 Pa;升温速率9℃/min;保温时间1.0小时。在此条件下,可完全脱除废催化剂的油质。并研究了此脱油过程中硫的走向与尾气的处理。     

Bohn's Test of Fiscal Sustainability of the American State Governments

The dramatic fall in state revenues during the Great Recession and the resultant large budget deficits accentuated concerns about state fiscal sustainability. I employ a model‐based approach proposed by 1998 to test for sustainability. In this approach, a positive and significant reaction of the ratio of primary surplus ratio (s) to lagged debt constitutes a sufficient condition for sustainability. Based on a panel of 48 contiguous states (1961–2008) and several model specifications, I find robust evidence in favor of sustainability. Further analysis suggests that the adjustment of the components of s to debt is asymmetric with the revenue side bearing a heavier burden than the spending side. The response of s is also found to be asymmetric with respect to the level of debt. Finally, the magnitude of the response is larger in states with a higher degree of fiscal stringency in general and “own‐revenue” and “no‐deficit‐carryover” provisions in particular.