A cold-cathode Penning Ion Gauge(PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics.The design considerations and some testings are presented.Ex...A cold-cathode Penning Ion Gauge(PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics.The design considerations and some testings are presented.Experimental results of Balmer-line-Emission show that the discharge characteristic,which is mainly determined by gas-flow rate,is not very sensitive to arc current and magnetic field in the operation ranges of the cyclotron.The arc power decreases and ascends while the gas-flow rate goes up from 0.5 SCCM to 20 SCCM.By improving the sealing design and reducing the machine tolerance of the source,the minimum power consumption reduces from 9 SCCM to 4 SCCM,thus having better energy efficiency and benefiting for the pumping system.Preliminary DC extractions show that H–microampere current ranges from several tens to hundreds under different operation conditions.Some problems during the experiments and future plan are discussed in the end.展开更多
A Penning ion gauge （PIG）-type ion source has been used for the generation of negative hydrogen ions （H-） as the internal ion source of the compact cyclotron. The discharge characteristics of the ion source are sy...A Penning ion gauge （PIG）-type ion source has been used for the generation of negative hydrogen ions （H-） as the internal ion source of the compact cyclotron. The discharge characteristics of the ion source are systematically studied for hydrogen operation at different discharge currents and gas flow rates on the prototype cyclotron. The preliminary study results for the low DC voltage H- extraction measurements are presented in this paper. The H- beam current is measured by the order of magnitude from several tens to hundreds of microamperes at different parameter conditions. The discussion and analysis for the experimental results are good for improving the design and working stability of the ion source.展开更多
旨在研究中国本土槐猪和引入瘦肉型猪(杜洛克猪、大约克夏猪、长白猪)在生长育肥相关基因MC4R和MSTN、脊椎数量相关基因NR6A1和VRTN、肉质性状相关基因PHKG1和PRKAG3以及病原感染相关基因SYNGR2和FUT1这8个基因9个SNP位点的遗传变异特...旨在研究中国本土槐猪和引入瘦肉型猪(杜洛克猪、大约克夏猪、长白猪)在生长育肥相关基因MC4R和MSTN、脊椎数量相关基因NR6A1和VRTN、肉质性状相关基因PHKG1和PRKAG3以及病原感染相关基因SYNGR2和FUT1这8个基因9个SNP位点的遗传变异特征。利用竞争性等位基因特异性PCR(KASP)和聚合酶链反应-限制性片段长度多态性(PCR-restriction fragment length polymorphism,PCR-RFLP)方法对突变位点进行基因分型,根据原始文献对各位点进行有利等位基因判定,并制作各猪种在各位点有利等位基因和不利等位基因的百分比示意图。结果:槐猪在NR6A1基因突变位点存在一定多态性,有利等位基因频率为0.24,其他位点表现为单一基因型,其中,PHKG1、PRKAG3突变位点为有利等位基因,而在MC4R、MSTN、VRTN、SYNGR2和FUT1突变位点为不利等位基因;杜洛克猪在MC4R、NR6A1、VRTN、SYNGR2和FUT1突变位点有利等位基因占优,然而,PHKG1基因不利等位基因仍有一定的比例;大约克夏猪在MC4R、SYNGR2、NR6A1和VRTN基因突变位点有利等位基因占优,而其他位点为不利等位基因;长白猪在MC4R、MSTN、PRKAG3(p.Val249Ile)和SYNGR2这4个基因突变位点不利基因占优;杜洛克猪在VRTN基因、长白猪在MC4R基因突变位点处于遗传不平衡状态(P<0.05)。以上结果为槐猪品种保护与利用以及瘦肉型猪种分子遗传标记选育提供了有益的信息。展开更多
【目的】分析新疆圆环病毒2型(Porcine circovirus type 2,PCV2)和3型(Porcine circovirus type 3,PCV3)的流行状况。【方法】在2022年10月~2023年9月,采用荧光定量PCR对采集的7个规模化养猪场的1403份样品进行检测和测序。【结果】PCV...【目的】分析新疆圆环病毒2型(Porcine circovirus type 2,PCV2)和3型(Porcine circovirus type 3,PCV3)的流行状况。【方法】在2022年10月~2023年9月,采用荧光定量PCR对采集的7个规模化养猪场的1403份样品进行检测和测序。【结果】PCV2总体阳性率为3.20%(45/1403),PCV3总体阳性率为33.00%(463/1403),PCV2和PCV3混合感染率为7.84%(11/1403)。C场PCV2和PCV3阳性检出率最高,PCV2为7.46%(10/134),PCV3为64.18%(36/134),PCV2和PCV3混合感染率为3.73%(5/134)。乳猪睾丸液检出PCV2和PCV3阳性率最高,PCV2阳性率为4.78%(25/523);PCV3检出率为57.36%(300/523)。PCV2和PCV3在一年四季中检出率均较高,且PCV3毒株为PCV3b和PCV3c型。【结论】新疆部分规模化养猪场中存在PCV3感染,PCV3流行率远高于PCV2,PCV3流行毒株为PCV3b和PCV3c型。展开更多
为了利用柯乐猪资源开发能抑制猪链球菌2型(Streptococcus suis serotype 2,SS2)且具有良好抗逆性和安全性的芽孢杆菌,试验从成年健康柯乐猪母猪粪便中分离芽孢杆菌,纯化后通过生化鉴定和16S rDNA基因的序列分析对分离菌株进行进一步鉴...为了利用柯乐猪资源开发能抑制猪链球菌2型(Streptococcus suis serotype 2,SS2)且具有良好抗逆性和安全性的芽孢杆菌,试验从成年健康柯乐猪母猪粪便中分离芽孢杆菌,纯化后通过生化鉴定和16S rDNA基因的序列分析对分离菌株进行进一步鉴定,并对芽孢杆菌分离株进行广谱抑菌能力检测、猪链球菌2型临床菌株抑制能力检测、抗逆性评估(耐热性能检测、人工胃肠液耐受试验和胆盐耐受试验)及安全性评估(溶血性试验、小鼠安全性检测和耐药性检测)。结果表明:分离、纯化并鉴定到1株枯草芽孢杆菌,命名为枯草芽孢杆菌S-3;枯草芽孢杆菌S-3对4种革兰氏阳性菌(猪链球菌2型、猪链球菌1/2型、猪链球菌8型和金黄色葡萄球菌)和2种革兰氏阴性菌(大肠杆菌和肠炎沙门菌)均有抑制作用;且对猪链球菌2型和金黄色葡萄球菌的抑制作用较为明显。枯草芽孢杆菌S-3株与猪链球菌2型共培养体系及枯草芽孢杆菌S-3株培养上清液均可完全杀灭猪链球菌2型。随着温度的升高,枯草芽孢杆菌S-3株的存活率逐渐下降,当温度达到90℃时存活率为50.9%。该菌株在人工胃液、人工肠液、0.3%胆盐溶液和0.5%胆盐溶液中处理3 h的存活率分别为52.88%、92.35%、53.51%、54.24%。枯草芽孢杆菌S-3株无溶血性,灌喂后小鼠精神状态、行为和采食情况未见异常,各组织器官无明显病理变化,且对15种常见抗生素未表现出耐药性。说明分离到的枯草芽孢杆菌S-3具有广谱抑菌活性,对猪链球菌2型具有很好的抑制效果,并具有耐热、耐酸、耐胆盐的特性及良好的安全性,可作为理想的益生菌候选菌株。展开更多
基金Supported by Army-Civilian Technology Development of CAEP(No.JM200701)National Natural Science Foundation of China(No.11105130)Science Foundation of CAEP(No.2012B0402056)
文摘A cold-cathode Penning Ion Gauge(PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics.The design considerations and some testings are presented.Experimental results of Balmer-line-Emission show that the discharge characteristic,which is mainly determined by gas-flow rate,is not very sensitive to arc current and magnetic field in the operation ranges of the cyclotron.The arc power decreases and ascends while the gas-flow rate goes up from 0.5 SCCM to 20 SCCM.By improving the sealing design and reducing the machine tolerance of the source,the minimum power consumption reduces from 9 SCCM to 4 SCCM,thus having better energy efficiency and benefiting for the pumping system.Preliminary DC extractions show that H–microampere current ranges from several tens to hundreds under different operation conditions.Some problems during the experiments and future plan are discussed in the end.
基金supported by Military-Civilian Technology Development of CAEP (JM200701)
文摘A Penning ion gauge （PIG）-type ion source has been used for the generation of negative hydrogen ions （H-） as the internal ion source of the compact cyclotron. The discharge characteristics of the ion source are systematically studied for hydrogen operation at different discharge currents and gas flow rates on the prototype cyclotron. The preliminary study results for the low DC voltage H- extraction measurements are presented in this paper. The H- beam current is measured by the order of magnitude from several tens to hundreds of microamperes at different parameter conditions. The discussion and analysis for the experimental results are good for improving the design and working stability of the ion source.
文摘旨在研究中国本土槐猪和引入瘦肉型猪(杜洛克猪、大约克夏猪、长白猪)在生长育肥相关基因MC4R和MSTN、脊椎数量相关基因NR6A1和VRTN、肉质性状相关基因PHKG1和PRKAG3以及病原感染相关基因SYNGR2和FUT1这8个基因9个SNP位点的遗传变异特征。利用竞争性等位基因特异性PCR(KASP)和聚合酶链反应-限制性片段长度多态性(PCR-restriction fragment length polymorphism,PCR-RFLP)方法对突变位点进行基因分型,根据原始文献对各位点进行有利等位基因判定,并制作各猪种在各位点有利等位基因和不利等位基因的百分比示意图。结果:槐猪在NR6A1基因突变位点存在一定多态性,有利等位基因频率为0.24,其他位点表现为单一基因型,其中,PHKG1、PRKAG3突变位点为有利等位基因,而在MC4R、MSTN、VRTN、SYNGR2和FUT1突变位点为不利等位基因;杜洛克猪在MC4R、NR6A1、VRTN、SYNGR2和FUT1突变位点有利等位基因占优,然而,PHKG1基因不利等位基因仍有一定的比例;大约克夏猪在MC4R、SYNGR2、NR6A1和VRTN基因突变位点有利等位基因占优,而其他位点为不利等位基因;长白猪在MC4R、MSTN、PRKAG3(p.Val249Ile)和SYNGR2这4个基因突变位点不利基因占优;杜洛克猪在VRTN基因、长白猪在MC4R基因突变位点处于遗传不平衡状态(P<0.05)。以上结果为槐猪品种保护与利用以及瘦肉型猪种分子遗传标记选育提供了有益的信息。
文摘【目的】分析新疆圆环病毒2型(Porcine circovirus type 2,PCV2)和3型(Porcine circovirus type 3,PCV3)的流行状况。【方法】在2022年10月~2023年9月,采用荧光定量PCR对采集的7个规模化养猪场的1403份样品进行检测和测序。【结果】PCV2总体阳性率为3.20%(45/1403),PCV3总体阳性率为33.00%(463/1403),PCV2和PCV3混合感染率为7.84%(11/1403)。C场PCV2和PCV3阳性检出率最高,PCV2为7.46%(10/134),PCV3为64.18%(36/134),PCV2和PCV3混合感染率为3.73%(5/134)。乳猪睾丸液检出PCV2和PCV3阳性率最高,PCV2阳性率为4.78%(25/523);PCV3检出率为57.36%(300/523)。PCV2和PCV3在一年四季中检出率均较高,且PCV3毒株为PCV3b和PCV3c型。【结论】新疆部分规模化养猪场中存在PCV3感染,PCV3流行率远高于PCV2,PCV3流行毒株为PCV3b和PCV3c型。
