Acquisition of a Low Vacuum Scanning Electron Microscope

正在请求经费购买具有数字图像储存和输出能力的低真空扫描电子显微镜。推荐购买的型号为JEOL JSM-5410LV，在高真空模式下可实现4 nm的分辨率，在低真空模式下可实现5.5 nm的分辨率。加速电压范围从0.5到30kv，放大倍数可高达200000倍或低至15倍。在低真空和高真空模式下，样品室压力分别从270 Pa （2 Torr）到7 X 10-4 Pa （5 X 10-6 Torr）。具有这些规格的扫描电镜对于植物学研究具有许多优点，但主要优点是可以直接观察植物组织，而无需在低真空模式下进行化学固定，脱水或金属涂层。这不仅可以节省准备时间，而且还可以更准确地表示待观察的精美标本，在某些情况下，可以避免改变或实际破坏具有独特特征的标本，例如古植物材料。此外，标本的数字图像可以以电子方式存储，并作为TIFF文件添加到数据库中的植物标本记录中。高真空模式也可用于提供高分辨率成像，可与目前市场上使用钨电子源的传统SEM相媲美。扫描电镜是植物系统和形态研究中不可缺少的仪器。纽约植物园（NYBG）申请资金购买一台新的扫描电镜，以取代目前使用10年的仪器，该仪器已接近使用寿命。扫描电镜用于NYBG研究花粉粒、孢子和各种植物组织，如表皮、维管成分和花成分。这样的调查提供了微观形态数据，这对花园的工作人员和研究生的研究至关重要。该仪器还将用于鉴定各种植物样本，作为古民族植物学调查的关键组成部分，并为公众和某些政府机构提供必要的信息。该提案包括使用SEM在NYBG进行的研究活动和识别服务的详细描述。先前NSF资助的结果：D. L. Lentz在过去五年内没有收到NSF资助。

Funds are being requested for the acquisition of a low vacuum scanning electron microscope (SEM) with a digital image storage and output capability. The model proposed for purchase, a JEOL JSM-5410LV, can achieve a resolution of 4 nm in the high vacuum mode and 5.5 nm in the low vacuum mode. Accelerating voltages range from 0.5 to 30 kV and magnifications can be as high as 200,000X or as low as 15X. Specimen chamber pressures vary from 270 Pa (2 Torr) to 7 X 10-4 Pa (5 X 10-6 Torr) in the low and high vacuum modes, respectively. A SEM with these specifications has many advantages for botanical research, but the main asset is that plant tissues can be observed directly without the need for chemical fixation, dehydration or metal coating in the low vacuum mode. This will not only represent a savings in preparation time, but also will provide more accurate representations of delicate specimens to be observed and in some cases will obviate the need to alter or actually destroy specimens that are unique in character, e.g., paleobotanical material. Furthermore, digital images of specimens can be stored electronically and added as TIFF files to databased botanical specimen records. The high vacuum mode also can be used to provide high resolution imaging comparable to currently-marketed, conventional SEM's that employ a tungsten electron source. The SEM is an indispensable instrument for systematic and morphologic plant research. The New York Botanical Garden (NYBG) requests funds to purchase a new SEM to replace the currently used 10-year-old instrument, which is nearing the end of its useful life. The SEM is used at the NYBG to investigate pollen grains, spores and various plant tissues such as epidermises, vascular elements and floral components. Such investigations provide micromorphological data that are essential to the research of the Garden's staff and graduate students. The instrument also will be used for the identification of varying plant samples as a key compo nent of paleoethnobotanical investigations and for the purpose of supplying essential information to the public and certain government agencies. The proposal includes detailed descriptions of research activities and identification services performed at the NYBG using the SEM. Results from Prior NSF Support: D. L. Lentz has not received an NSF grant within the last five years.