{'fraction_non_alphanumeric': 0.015780730897009966, 'fraction_numerical': 0.0004152823920265781, 'mean_word_length': 5.546195652173913, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Double-template synthesis of CdS nanotubes with strong electrogenerated chemiluminescence.

In recent years, there has been growing interest in the fabrication of hollow nanostructures owing to their important applications in catalysis, sensors, controlled release, and electronic and optical devices. To date, methods for the fabrication of the hollow nanostructures have mainly been based on the self-assembly or deposition on surfaces of colloidal particles. However, these methods are relatively complicated; surface modification of colloid particles is often required to ensure the coating of shell substances, and chemical etching or calcinations are required to remove the cores in order to obtain the final hollow structures. It is highly desirable to develop an efficient and facile method to prepare hollow materials. Soft-template methods provide a simple and general process for generating hollow structures. Surfactants and other polymer molecules can self-assemble into rodlike or sphere-shaped mesophase structures. These structures can serve as soft templates, around which the desired materials are generated in situ and shaped into hollow structures with a morphology complementary to that of the templates. In addition, some metallic hollow structures have recently been prepared by a method involving the conversion of sacrificial metal templates. During the conversion reaction, the metal templates can be gradually evacuated through surface defects while the resultant metal shells preserve the shapes of original templates. Combining the soft template with the sacrificial template, we have designed a novel double-template route to fabricate hollow structures. The fabrication process is illustrated in Scheme 1. First, a sacrificial template with desired shape is prepared. Based on the sacrificial template, the soft template is constructed by coating appropriate molecules onto it and thus the double template is fabricated. During the following conversion reaction, the internal sacrificial template is consumed to form a hollow interior. The resultant material then simultaneously grows on the external soft template and forms a shell with a shape complementary to that of the original sacrificial template. Gelatin is an amphoteric polyelectrolyte consisting of amino acid groups. It has good biodegradable properties and has been widely used as a colloidal protective agent due