研发投入跳跃是企业正确把握产品生命周期,实现研发策略转换,稳固竞争优势的重要环节,但企业金融化一定程度上干扰了原有的研发环节.本文基于 2011-2020 年中国沪深A股上市非金融企业面板数据,采用固定效应面板门槛模型,分析企业不同金融化程度下,研发投入跳跃与企业经营绩效、价值绩效的非线性关系;并探究研发回报率和研发产出弹性的非线性变化规律.结果表明:①研发投入跳跃与企业价值绩效之间存在企业金融化的双门槛效应,二者呈现以企业金融化为 44.11％为分段点的近V字形关系.②研发回报率、研发产出弹性存在企业金融化的门槛效应,当企业金融化处于 0％～6％(±1％)的区间内,研发回报率与研发产出弹性均为正,较为适合进行研发投入;当企业金融化程度逐步加深,研发回报率会出现下降—增加—下降的波动.最后结合分析结果,对企业金融化趋势下的企业经营与政府监管提出了相应的建议.

为了解冷冻食品中大肠杆菌污染情况,分析其潜在的食品安全问题,从陕西省4市(宝鸡、咸阳、西安和渭南)共收集冷冻食品样品360份(120份速冻水饺和240份冰淇淋).通过选择培养和聚合酶链式反应(polymerase chain reaction,PCR)进行大肠杆菌分离鉴定.然后对分离株进行21种毒力基因、23种耐药基因、15种抗生素耐药性检测及种群分型.360份样品中大肠杆菌污染率为13.6％(49/360),其中5份样品(10.2％,5/49)大肠菌群计数超过100CFU/g.21种被检毒力基因中有9种毒力基因被检出,以肠外致病性大肠杆菌相关基因FyuA和iss的检出率最高(均为14.3％,7/49).药敏结果显示,菌株对β-内酰胺类抗生素和叶酸代谢抑制剂的耐药最为普遍(均为98.0％,48/49),其次为四环素(20.4％,10/49).其中β-内酰胺类主要编码基因为blaCTX,四环素主要编码基因为tetA.研究还发现1株分离株携带多黏菌素类抗性基因mcr-9.此外,20.4％的菌株为多重耐药菌株,最多可对13种抗生素耐药.所有分离株共有4种系统发育群(A、B1、C和F),A群为优势群系(63.3％,31/49).综上,陕西省典型冷冻食品中存在致病性大肠杆菌及耐多药菌株污染,存在通过食物链传播给人的风险.

电子商务与社区团购的发展使农产品增加了线上销售渠道,由此产生了农产品双销售渠道与传统线下销售渠道的冲突问题.试在分销商经销与代销两种销售模式下构建博弈模型,探讨农产品双销售渠道的供应链决策.结果表明:不同销售模式下,供应链的最优决策不同,但农产品线上销售渠道的发展有利于加快农产品流通、提高农产品质量、提升行业水平;消费者剩余与农产品质量存在非线性关系,供应商需要对农产品质量进行合理把控;农产品线上销售渠道的发展对龙头企业、分销商、零售商的预期收益具有挤出效应.因此,依旧不可忽视线下销售渠道的重要性.

提高牧户草原保护意愿对于草地资源可持续利用具有重要的现实意义.文中以内蒙古达茂旗和四子王旗421户牧户的微观数据为基础,运用结构方程模型分析了牧户生态认知和家庭生计资本对牧户草原保护意愿的影响.结果 显示:1)生态认知和家庭生计资本均对牧户草原保护意愿有显著的正向影响,且生态认知对牧户草原保护意愿的影响显著高于家庭生计资本;2)家庭生计资本对牧户草原保护意愿影响的直接路径(家庭生计资本→草原保护意愿)系数远大于间接路径(家庭生计资本→生态认知→草原保护意愿)系数.政策启示:一,大力开展草原保护宣传工作,强化牧户生态认知,使其意识到草原保护的正外部性;二,引导牧户转向生态旅游、农家乐等其他生计活动,多样化牧户金融资本的来源方式,从提高农户金融资本的角度提升牧户家庭生计资本,从而减少牧户为寻求经济效益而对草原进行掠夺性开发的行为;三,完善草原网络覆盖、开展牧户集体活动,加强牧民之间的联系,从丰富牧户社会资本的角度提高牧户家庭生计资本.

The growth of tea plant is affected by environment conditions to a great extent,but the effects of different meteorological factors on tea production is different.Meteorological factors and tea yield as targets in 8 main tea-producing area in southern Shaanxi during 2007 to 2016 were studied.The grey correalation was used to study the relationship between meteorological factors and tea yield.The results showed that annual average relative humidity,extreme maximum temperature and average temperature were the main factors affecting tea yield in Southern Shaanxi.

Loop is the key mechanism of rod and wire rolling process,when the production line to replace rolling specification,or replace the looper and roll or roller seam adjustment,easy to appear unstable looper rising up too high,or pull phenomenon. Causes the PID parameter cannot be original control loop fast or stable adjustment set high,make the mill automatically adjust the need for a longer period of time to get to the matching speed,in extreme condition,will cause the broken or pile of steel,influenced the efficiency change specifications,and wastes. This paper put forwards a method without changing the original PID gain parameters in the premise,through adjusting the set target value,to achieve rapid rolling structured variable specification or pass after the scheduled.

Objective To develop a rapid detection method of usual antibiotics resedues in goat milk by electronic nose. Methods The goat milk with four concentrations (0, 50, 100, and 200μg/L) antibiotics, in-cluding penicillin, gentamycin and streptomycin was detected by electronic nose as a rapid non-destructive de-tecting equipment, to collect the volatiles emitted from the goat milk. Then the linear discriminant analysis (LDA) was applied to analyze the results and the response signals were chosen for the pattern recognitions by multilayer perceptron neural network (MLPN). Results LDA results showed that the response signals of the goat milk could distinguish the concentrations of antibiotics. The correct rates of the training group and the testing group of MLPNs were both more than 94.9%. Conclusion MLPN can be used as an effective fore-casting tool for predicting the concentration of three kinds of antibiotic in goat milk using the signals of elec-tronic nose.

A new method for the discrimination of raw meat and water-injected meat by means of near infrared spectroscopy(NIRS) was developed.First,raw meat and water-injected meat were collected.Using Near-infrared Spectroscopy to scan the samples and get the spectrum data.The principal component analysis(PCA) and A three-layer back-propagation neural network(BP-ANN) was developed for qualitative discrimination,which had been preprocessed with the second derivative and 25 point smoothing.Results show that the accumulative reliabilities of the first fifth components were more than 99.626 %,and chose ANN-BP as further research method.The first five components were then applied as ANN-BP inputs and the values of the type of meat were applied as the outputs.A three-layer back propagation neural network model was developed for classification.Finally,the result indicated the distinguishing rate of 109 calibration samples is 91.74 % and the distinguishing rate of 30 unknown test samples is 90 %.This model is reliable and practicable.So the present paper could offer a new approach to the fast discrimination of water-injected meat.

A rapid detection was made to determine goat milk with different concentrations of antibiotics(oxytetracycline,streptomycin,gentamicin) using an electronic nose(E-nose).The data obtained by electronic nose (E-nose) were analyzed by the method of principle components analysis(PCA) and Linear Discriminant Analysis(LDA).The results analyzed by LDA were superior to that by PCA,which could distinguish all the milk samples completely.However PCA just could discriminate the samples with streptomycin.E-nose could detect those three antibiotics in goat milk with different concentrations effectively and rapidly.

For optimization of component extraction from loquat wine by HP-SPME,the extraction conditions were investigated using single factor and response surface methodology based on Box-Benhnken centre design principles.The extraction temperature,extraction time and sample volume were used as affected factors while the total peak area of chromatogram as response value in this study.The results indicated that the optimum conditions for aroma components extraction from loquat wine by HP-SPME were obtained as followed: extraction temperature 38.0℃,extraction time 32.5min and sample volume 8.5mL.Under the above conditions,26 different compounds were identified.In the sample,the content of alcohols was 47.33%,of esters was 37.73%,of acids was 0.9% and of aldehydes was 0.32%.Among them,phenylethyl alcohol,1-nonanol,diethyl succinate,methyl salicylate,hexanoic acid,ethyl caprylate and ethyl 2-methylbutyrate were the main compounds.

The goal of this study was to develop an optimum process for hydrolyzing loquat slurry.A series of single factor experiments were carried out to address the effects of enzyme concentration,hydrolysis temperature and length of hydrolysis on juice yield and transmittance.Central composite design coupled with response surface methodology was employed to optimize these 3 hydrolysis conditions.It was indicated that all of the conditions significantly influenced juice yield and transmittance and that their optimum values were determined as follows: enzyme concentration 166.05 mg/kg,hydrolysis temperature 40.60 ℃ and hydrolysis duration 5.64 h.Under these optimum conditions,the experimental values of juice yield and transmittance were 91.17% and 76.24%,respectively,presenting a relative error of less than 1% when compared with the predicted counterparts.

In this paper,the researches of SPME from coating,extraction device,extraction mechanism and combination with other analysis instruments were summarizes on the base of extraction principles in recent ten years,and then its applications in fermented meat products were listed.The promising prospect of SPME for future application in fermented meat products was also stated at last.

This paper summarized the resources and varieties,the chemical compounds and functions of radices puerarire,analyzed the current status on research and exploitation of the food of radices puerarire.

The relative percentages of aromatic components in fresh lemon juice and that hydrolyzed by β-glucosidase were analyzed and determined by GC-MS. A total of 25 aromatic components were identified:23 in the fresh lemon juice and 25 in the enzyme-hydrolyzed juice. The amount of aromatic components increased by 11% in the enzyme-hydrolyzed juice,with somewhat increase in the categories but slight change in the relative composition of the contents,which indicated that enzymolysis not only retained the well-coordinated aromas in the fresh lemon juice but also released potential aromatic substances to make up for their losses in processing.

This paper introduces the research progresses of flavour compound in fermented meat products,including their sources,factors,distilling and identification.

Functional food is the food which is able to regulate the body,prevent disease and promote health,but notf orh ealingt hei llness.Functionalm eatp roduct not only provides nutrition for people such as high gradep rotein,minerals ubstancea ndv itamine tal,but also has the certain function of health protection.Thisp aperi ss tudiedo ne xploitationo f functional meat products by appending dietary fiber into the raw meat.

Functional food is the food which is able to regulate the body,prevent disease and promote health,but not for healing the illness.Functional meat product not only provides nutrition for people such as high grade protein,mineral substance and vitamin et al,but also has the certain function of health protection.This paper is studied on the exploitation of functional meat products by appending dietary fiber into the raw meat.