Will Higher Industry Concentration Promote Food Safety?

Given the serious situation of food safety in China, the Chinese government has followed the policy of diverting resources to certain competitive firms and thus increasing market concentration as a means to improve food safety. This policy departs from the common practice in advanced economies of encouraging competition and restraining excessive corporate expansion. Based on the theoretical analysis framework of game theory, this paper investigates the impact of increased industry concentration on food safety. Our study finds that in a market environment where quality food enjoys a high premium, greater evenness of corporate size across firms will be conducive to mutual cooperation among firms for the provision of quality and safe food. Yet if the market is less sophisticated and the premium for quality food is low, it will be difficult to form mutual cooperation among firms and easier for low quality food manufacturers to take a free ride. In these circumstances, the larger size of quality food firms will make them less vulnerable to be affected by free rides and more motivated to manufacture quality and safe food. The latter scenario is consistent with China's market reality. Hence, increasing industry concentration in the current stage is conducive to mitigating the food safety crisis. Yet with the gradual improvement in market conditions, a competitive policy will be a better option in the long run.

25%Amistar SC(阿米西达水悬浮剂)在苹果病害管理中的应用

对具有保护和治疗双重功效的仿生性杀菌剂25%AmistarSC(阿米西达水悬浮剂)在苹果病害管理体系中的应用技术和定位进行了探讨。结果表明,25%AmistarSC除对嘎拉品种有药害外,对黄元帅、秦冠、红富士、新红星、北斗、澳州青苹等6个骨干品种均无任何不良影响,使用安全;同时,25%AmistarSC对苹果白粉病、黑星病及斑点落叶病等3种主要病害均具有显著防治效果,使用浓度1500～2000倍,防治效果达80%～90%;在广谱性和防治效果上显著优于目前生产上推广的常用的苯并咪唑类、三唑类及代森类杀菌剂品种。应用时应在发病前或发病初期施药,间隔7～10d喷1次,连喷3～4次为宜,同时宜与具有其他作用机制的杀菌剂,如苯并咪唑类、三唑类等内吸性杀菌剂混用或交替用药。

ATHLET-SC程序的开发及适用性分析

由于超临界水堆(SCWR)在系统简化、降低成本和提高热效率上的优势,SCWR的研究在全球范围内得到广泛关注。在众多有关超临界水堆的研发工作中,开发适用于SCWR的系统分析程序是进行SCWR系统设计和安全评估的关键技术难题之一。本工作基于最佳估算系统分析程序ATHLET2.1A,增加了超临界热物性参数,开发出适用于SCWR的系统分析程序ATHLET-SC,将现有的ATH-LET程序扩展到超临界压力状态。为评估修改后的程序的适用性,建立了混合能谱超临界水堆堆芯模型,并对该模型进行了功率瞬态计算。此外,对1个简化的超临界水冷却回路进行了稳定性分析。计算结果表明:修改过的ATHLET程序(ATHLET-SC)对SCWR系统的模拟具有良好的适用性。

SCS模型在岚河流域的应用研究

介绍了SCS模型,在保留SCS模型物理意义的前提下,将SCS模型引用到位于汾河水库上游的中型流域岚河流域,通过对该流域实测降雨、洪水资料的分析,提出了适合该流域产流计算的CN值表和用于流域汇流计算的无因次单位线以及相应的汇流参数关系式。

基于SC-IAT的矿工内隐安全态度研究

为预防矿工习惯性违章行为发生,预防人因事故,采用单类内隐联想测验（SC-IAT）测量矿工安全态度的内隐性。首先,通过Inquisit 4.0心理学软件编制SC-IAT安全态度测量程序,试验验证矿工安全态度内隐性是否存在;然后,设计矿工安全态度量表,测量矿工的外显安全态度;最后,运用SPSS 21.0分析内隐安全态度测量结果与外显安全态度测量结果的关系。结果表明：被试整体上存在正向、积极的内隐安全态度;年龄、受教育程度、工作岗位等人口统计学指标对矿工内隐安全态度无显著影响;内隐安全态度与外显安全态度之间不存在相关关系,它们属于不同的建构。

25%阿米西达SC防治苹果斑点落叶病田间药效试验

通过对 2 5 %阿米西达SC防治苹果斑点落叶病进行田间药效试验。结果表明 ,2 5 %阿米西达SC对苹果斑点落叶病有较好的防治效果 ,防效达 80 %～ 90 % ,而且与环境友好 ,使用安全。田间适宜使用浓度为 0 .16 7～ 0 .1g L倍 ,间隔 10d喷 1次 ,连喷 4次为宜。

25%阿米西达SC对苹果树安全性及防治苹果白粉病的药效试验

本试验在田间条件下 ,研究了 2 5 %阿米西达SC对不同苹果树品种的安全性及其防治苹果白粉病的药效和使用浓度。结果表明 :2 5 %阿米西达SC对澳州青苹、北斗、黄元帅、新红星、红富士、秦冠 6个苹果品种安全性较好 ,无任何不良影响 ,但对嘎啦品种的苹果树有严重的药害产生 ,导致果锈和叶片焦枯脱落。 2 5 %阿米西达SC对苹果白粉病有较显著的防效 ,防效可达 85 %～ 90 % ,使用浓度为 0 .12 5g L～ 0 .0 83g L ,间隔期 7d喷 1次 ,连喷 3次。

10%三氟苯嘧啶SC拌种水稻对稻飞虱的防效及安全性评价

【目的】探明不同种植方式下10%三氟苯嘧啶SC拌种水稻后对稻飞虱的田间防治效果及对天敌蜘蛛和水稻的安全性,为该药剂拌种水稻防治稻飞虱提供理论依据。【方法】以不同浓度(22.5、45.0、67.5和90.0 g a.i./ha)的10%三氟苯嘧啶SC对杂交稻(丰优香占)和粳稻(南粳9108)进行拌种处理,以25%噻虫嗪WDG(135.0 g a.i./ha)为对照药剂,以清水处理为空白对照,室内分别测定拌种7和15 d后水稻种子的发芽率和出苗率,并在田间调查药剂拌种对稻飞虱的防治效果及对稻田蜘蛛和水稻的安全性。【结果】不同浓度10%三氟苯嘧啶SC拌种水稻后,各处理种子的发芽率和出苗率与空白对照均无显著差异(P>0.05)。10%三氟苯嘧啶SC用量≥22.5 g a.i./ha时,直播粳稻播种后98 d、杂交稻播种后126 d对稻飞虱的防效均在90.00%以上;机插秧粳稻播种后112 d、杂交稻播种后119 d对稻飞虱的防效均在90.00%以上;不同浓度10%三氟苯嘧啶SC拌种处理对旱育移栽秧田稻飞虱的防效较差,持效期短,自调查日起已基本丧失对稻飞虱的控制能力。对稻田蜘蛛调查及对水稻生长观察结果显示,直播稻和机插秧稻田蜘蛛种群数量均明显低于空白对照田,而不同处理旱育秧移栽田蜘蛛种群数量与空白对照田相当;不同浓度10%三氟苯嘧啶SC拌种处理对水稻生长发育无不良影响。【结论】利用10%三氟苯嘧啶SC 22.5~90.0 g a.i./ha拌种水稻可有效降低直播稻和机插秧田田间稻飞虱种群数量,对水稻安全,对天敌蜘蛛影响较小,可在水稻生产中推广应用。

Efficacy of Difenoconazole-azoxystrobin 32.5% SC in Treatment of Rice Sheath Blight and Its Application Technology

[Objective] The efficacy of difenoconazole-azoxystrobin 32.5% SC for rice sheath blight and its application technology were discussed in this research. [Method] Three surveys were carried out. There were 5 fixed test clumps in each plot. The number of total plants and disease plants and disease progression in each fixed clump were recorded. The correlation effectiveness was calculated based on the growth rate of disease index. Significance analysis was performed with Dun- can＇s new multiple range method （DMRT）. [Result] The difenoconazole-azoxystrobin 32.5% SC had a good efficacy for rice sheath blight, and its efficacy increased with the increase of dose. If sprayed according to the dose of 450 ml/hm2 5 days before the beginning of heading stage of rice, difenoconazole-azoxystrobin 32.5% SC would have better effects on controlling rice sheath blight with correlation effectiveness reaching up to 95.14%, which was 2.06% higher than that of control drug （trifloxys- trobin-tebuconazole 75% WG, 225 g/hm2）. [Conclusion] Treated with difenoconazole- azoxystrobin 32.5% SC with dose of 450 ml/hm2, rice would have green upper leaves and less yellow middle and lower leaves. Moreover, the yield was in- creased significantly. The difenoconazole-azoxystrobin 32.5% SC had good safety. Therefore, difenoconazole-azoxystrobin 32.5% SC had a good application prospect in production.

6%双氟磺草胺·唑嘧磺草胺SC防除春小麦田阔叶杂草药效试验

为明确新型除草剂6%双氟磺草胺·唑嘧磺草胺SC对春小麦田杂草防治效果、最佳用量和对春小麦的安全性,采用田间随机区组试验设计,在春小麦3~5叶期进行茎叶喷雾处理,通过两年药效试验,调查杂草防除效果及春小麦安全性。结果表明,推荐剂量6%双氟磺草胺·唑嘧磺草胺SC有效成分用量10.35~12.60 g·hm^(-2),药后40 d对密花香薷、黎、野油菜防效达80%以上,后期目测防效81.33%~89.32%,并对小麦具有较好的安全性,增产率为10%以上。

4%双唑草腈SC对直播水稻的安全性及除草活性研究

双唑草腈(Pyraclonil)系原卟啉原氧化酶(PPO)抑制剂。为了明确其在直播水稻田的应用前景,采用室内生物测定和田间小区试验法,分别研究4%双唑草腈SC随播随用和水稻1—2叶期、2—3叶期茎叶喷雾对‘南粳46’(常规粳稻)、‘申优26’(杂交粳稻)、‘旱优73’(籼稻)3种类型水稻品种不同芽长、稻谷出苗与生长的影响以及其除草活性。结果表明:在稻谷浸种不催芽、露白、芽长半粒谷等3种不同催芽状态下,4%双唑草腈SC 1500 mL∕hm^(2)随播随用处理对3个供试水稻品种的出苗数、株高、地上部鲜重均无不良影响,但当4%双唑草腈SC用量提高至3000 mL∕hm^(2)时,各水稻品种的安全性表现不一;水稻1—2叶期和2—3叶期茎叶喷雾,4%双唑草腈SC 1500—3000 mL∕hm^(2)处理对水稻茎蘖数、株高、根长、地上和地下部鲜重等生长指标均表现安全。药后28 d调查,4%双唑草腈SC 1500—3000 mL∕hm^(2)随播随用处理对直播稻田主要优势杂草千金子、异型莎草、耳叶水苋、丁香蓼的株数防效均为100%,对稗的株数防效为74.99%—93.36%,对水稻的出苗数、株高和地上部鲜重无不良影响。研究结果显示,4%双唑草腈SC 1500 mL∕hm^(2)随播随用处理不仅对供试水稻品种安全,而且对直播稻田主要优势杂草有优异的防除效果。该研究为双唑草腈在直播稻田应用上取得了一定的研究成果,也为直播稻田交替使用随播随用土壤封闭除草剂提供了更多选择。

430g/L戊唑醇SC防治小麦赤霉病效果及应用技术

田间试验结果表明,430 g/L戊唑醇SC对小麦赤霉病有较好的防治效果,其药效随用药量加大而极显著上升。第2次用药后20,30 d,430 g/L戊唑醇SC 300 m L/hm2的防效分别达到94.43%和87.89%,比对照药剂50%多菌灵WP 1 350 g/hm2的防效高2.18百分点、2.21百分点,且对小麦安全性好。430 g/L戊唑醇SC在生产上有较好的推广应用前景。

Study on Scandium Separation from Rare Earth Ore in Yunnan Province

Chemical components, main mineral content and mineral composition of rare earth ore in Yunnan Province was measurated by the analysis of the spectrum and the chemical components. The study shows that main metals mineral in the rare earth ore are magnetite, tatanomagnetite, limonite; less metals mineral are ilmenite, hematite; some minim minerals were iron pyrites, zircon, scheelite, and so on. Main nonmetals mineral are quartz, feldspar(plagioclase, K-feldspar); less nonmetals mineral are hopfnerite, biotite, titanite; some minim minerals are kaolinite and dolomite. Ilmenite has the highest content of Sc as 175 g·t -1, next is titanite as 81.2 g·t -1. Based on this result, A new method of extracting Sc is put forward. The technological flowsheet of separating Sc of low-intensity magnetic separation,tabing, gravity concentrate, high-gradient magnetic separation, and electrostatic separation was prepared. Amplified experiment obtained Sc concentrate with Sc content of 148.54 g·t -1, the yield of 7.92%,recovery of 69.20%, at the same time, a Fe concentrate with the grade of 63.88% and the yield of 5.91% is obtained.

Sc对Al-3Cu-1Li合金酸性条件下腐蚀行为的影响

熔炼制备Al-3Cu-1Li-x Sc(x=0、0.1、0.3和0.5,wt%)合金,用原子发射光谱、X射线衍射和光学显微镜对其成分和显微组织进行测量和观察。在pH=2的硫酸溶液中,用电化学方法、X射线光电子能谱(XPS)和Mott-Schottky曲线研究Sc对该合金腐蚀行为和腐蚀产物膜的成分及内部缺陷的影响。结果表明:Sc未改变Al-3Cu-1Li合金的腐蚀机制和表面形成腐蚀产物膜具有的n型半导体特征;随Sc含量的增加,该合金自腐蚀电流密度增加,耐蚀性下降,与合金表面形成腐蚀产物膜的氧化程度降低及膜内氧空位浓度增加有关。

Study on Weed Control and Safety of Tembotrione-Atrazine Tank Mixture in Spring Maize Fields

This study aimed to explore the effect of 5% tembotrione oil dispersion(OD)-38% atrazine suspension concentrate(SC) tank mixture on the weeds in spring maize fields and the safety of the mixture. To be specific, randomized block design was adopted for the field experiments. The results showed that the application of tankmixture of 5% tembotrione OD at 90 g a.i./hm^(2)and 38% atrazine SC at 570 g a.i./hm^(2)and the mixture of 5% tembotrione OD at 90 g a.i./hm^(2)and 38% atrazine SC at 1140 g a.i./hm^(2)respectively controlled 94.7%~96.3% and 94.0%~96.3% of the grass weeds, 94.7%~96.0% and 93.7%~95.7% fresh weight of grass weeds, 95.3%~96.3%and 93.3%~97.3% of broadleaf weeds, and 94.7%~96.0% and 93.3%~96.3% fresh weight of broadleaf weeds. The efficacy was better than that of the 5% tembotrione alone and the control herbicide and no phytotoxicity of the mixtures was identified.The tank mixture of tembotrione and atrazine should be promoted in the spring maize field for weed control and the recommended dosages were 90 g a.i./hm^(2)for 5%tembotrione and 570 g a.i./hm^(2)for 38% atrazine.

Efficacy and Phytotoxicity Trial of Different Dosages of 4% Nicosulfuron SC on Weeds in Corn Fields

[Objective]The paper was to study efficacy and phytotoxicity of different dosages of 4% nicosulfuron on weeds in corn fields.[Method]With summer corn variety Zhengdan 958commonly used in field production in Hengshui area of Hebei Province of China as the test material,different dosages（1 050,1 500 and 1 950mL/hm2）of corn postemergence herbicide 4% nicosulfuron SC were sprayed during five-leaf stage of corn,and the treatments with water spraying and manual weeding were set as controls.The effects of different dosages of 4% nicosulfuron SC on weed control efficacy and safety and yield of corn were analyzed in order to determine the optimal dosage.[Result]Spraying 4% nicosulfuron SC with dosage of 1 500mL/hm2 during five-leaf stage of corn not only had better control effect against various weeds,but also did not produce phytotoxicity on corn,and the yield of corn was higher.[Conclusion]The study provided scientific information for using 4% nicosulfuron to eradicate weeds in corn fields.

Research on Distribution Regularities of Dust Concentration and Granularity in Large Mining Height Working Face

The key for dust control of coal mine is to clarify the dust concentration distribution and sedimentation in different areas. Both similarity experiment and numerical simulation method have certain restrictions and are quite different from the actual situation on site. In order to study the dust sedimentation regularity of coal mine in large mining height, “filter membrane method” is adopted in this paper, i.e., to dry and weigh the filter membrane before and after sampling, collect the dust of respirable zone on mining face and calculate the dust concentration based on a main airway of 100 m. The result shows that: A large amount of dust will be produced during coal mining, wherein the maximum dust concentration from 6 m upstream to 100 m downstream of coal cutter is 121 mg/m3, while the minimum dust concentration is 61 mg/m3;The dust concentration in return airway is reduced with the distance increases, while the dust concentration at the entrance is 91 mg/m3;A large amount of dust may fall from roof during section advancing and improves the dust concentration of hydraulic support in walking area obviously;The dust granularity of mining face and return airway is 0 - 100 μm, but the amount of respirable dust is higher than 80%, the larger the dust particle size, the higher the dust concentration. Besides, dust in small particle size can be suspended in air flow for longer, but that in large particle size may subside under the action of gravity;To reduce dust exposure, the mining position shall be located in the windward direction of advancing or coal cutter. This research can provide guidance for taking dust prevention measures of working face in large mining height.

基于杯式燃烧器测试系统的灭火性能评价研究进展

杯式燃烧器试验是消防领域用于测定气体灭火剂最小灭火浓度的经典方法。自哈龙灭火剂被淘汰以来,哈龙替代物经历了不同相态的发展,促使杯式燃烧器测试系统进行相应的改进,同时基于杯式燃烧器测试系统的灭火性能评价研究也在不断拓展。综述了国内外杯式燃烧器测试系统的使用和改进研究,重点介绍了适用于气相、液相、固相和复合相灭火剂的杯式燃烧器测试系统和测试方法,分别对气相、液相、含添加剂细水雾、干粉、复合灭火剂的灭火效率进行了总结和分析,综述了各相态灭火剂灭火性能评价研究。未来,杯式燃烧器测试系统仍将不断被改善,在灭火剂筛选和灭火性能评价等方面将发挥更重要的作用。

面向火电厂煤粉尘浓度的预测评估算法的研究

火力发电的主要能源来自煤炭,而由于燃煤发电过程中产生的煤尘扩散是引起火电厂粉尘爆炸风险和尘肺职业病的主要根源之一,因此必须进行实时有效的检测和控制。当前粉尘检测方法仅使用单一的粉尘质量浓度指标来评估粉尘污染整体状况,缺乏对多种复合因素影响的考量,依靠单一阈值设定进行报警,易出现误报、漏报等现象,以及忽略粉尘爆炸这一重要事故场景,不能建立粉尘污染全面客观的评价方法。研究建立了一种粉尘质量浓度预测模型,基于金豺优化算法对极限学习机的最优初始权重进行寻优,再使用极限学习机对样本数据进行训练学习,提高神经网络模型的精度,可较为准确地预测30 min以内任意时间间隔的粉尘质量浓度,并将现场数据及模拟仿真数据与建立的粉尘质量浓度预测模型进行对比分析。结果显示:建立的粉尘质量浓度预测模型准确度良好,与现场数据及模拟仿真数据对比误差分别为0.72%和2.1%,可加强对火电厂粉尘环境进行预测预警,从而及时采取合理的粉尘控制策略,确保火电厂的生产安全并降低粉尘对作业人员的职业危害。

拉考沙胺治疗4岁以下癫痫患儿疗效、安全性与血药浓度的相关性研究

目的 评估拉考沙胺(LCM)治疗4岁以下癫痫患儿的疗效、安全性与血药浓度的相关性。方法 回顾性纳入新疆维吾尔自治区儿童医院2019年1月1日至2023年12月31日期间190例使用LCM治疗的癫痫患儿,收集个人资料、记录LCM血药浓度、疗效及药品不良反应。分析疗效、安全性和血药浓度的相关性。结果 LCM治疗有效率为77.37%,不良反应发生率为31.58%。LCM血药浓度预判疗效的准确性[曲线下面积(AUC)(95%CI)=0.532(0.440~0.623)]高于给药剂量[AUC(95%CI)=0.525(0.422~0.628)]。癫痫患儿LCM稳态血药浓度参考区间为1.50~14.65μg·mL^(-1)。发生不良反应患儿的LCM血药浓度显著高于未发生不良反应组患儿[(7.93±3.90)μg·mL^(-1) vs(6.44±3.10)μg·mL^(-1),P<0.05]。结论 LCM治疗4岁以下癫痫患儿的疗效和安全性均较好,可用于临床癫痫治疗。。