Pengaruh Perubahan Kandungan Ion Logam (Cu2+, Fe3+, Ni2+ dan Zn2+) dan Mikrostruktur ke Atas Penumpas EMI Ferit Nizn

Perkembangan pesat teknologi dan penggunaan komunikasi elektronik dan komputer telah memberikan sumbangan besar kepada kehidupan manusia. Bagaimanpun perkembangan ini telah menghasilkan suatu bentuk interferens elektromagnet (EMI). Feritnikel zink adalah di antara bahan penumpas yang terbaik untuk menyerap gelombang EMI itu. Bagaimanapun, lebar jalur frekuensi serapannya adalah terhad sedangkan keperluan penumpasan EMI ini wujud bagi julat frekuensi yang amat lebar (KHz ke GHz). Dengan demikian projek ini bertujuan untuk: mengkaji bagaimana komposisi iaitu kandungan ion logam (Ni2+, Cu2+, Zn2+, dan Fe3+) dan mikrostruktur nikel zink ferit mempengaruhi eiri penumpasan EMI, terutamanya dari segi magnitud impedans penumpas dan kedudukan frekuensi resonannya.Dalam kajian ini metadologi dibahagikan kepada dua bahagian, iaitu penyediaan bahan dan pencirian. Penyediaan bahan dilakukan dengan kaedah oksida yang melibatkan pensinteran lazim seramik.. Dalam kajian ini kesan memasukkan ion gantian Zn2+ dan Cu2+ ke dalam struktur ferit spinel menjadi keutamaan. Mula-mula disediakan sampel-sampel dengan penambahan ion Zn2+ dan pengurangan Ni2+ untuk melihat kesan gantian ini terhadap sifat magnetnya. Selepas itu, dengan cara yang sama, dikaji tiga kes lain yang masing-masingnya tertumpu kepada kesan penambahan ion Cu2+ dan pengurangan Ni2+ Zn2+ atau Fe3+. Bahagian yang kedua adalah pencirian bahan. Ia melibatkan pengukuran parameter mikrostruktur, sifat-sifat elektrik dan sifat-sifat magnet. Hasil kajian yang diperolehi menunjukkan frekuensi resonan serapan boleh dianjak naik atau turun bergantung pada komposisi dan mikrostruktur yang digunakan. Nilai maksima impedans juga boleh dikawal dengan komposisi. Kedua-dua aspek ini, iaitu nilai frekuensi resonans dan nilai impedans disekitamya, sangat penting bagi penumpas EMI kerana magnitud impedans dan julat frekuensinya mesti sesuai dengan keperluan penumpas EMI bagi sesuatu peranti

FINDERS-APPLICATION OF STATUTE TO FINDER OF TREASURE TROVE

Defendants, a church committee, procured bundles of rags which were distributed to women who wove the rags into rugs. One such bundle was delivered to plaintiff who found $2100 in bills concealed therein. Plaintiff took the money to defendants, but no claimant appeared. A statute provided that a finder of lost money or goods having a value of$3.00 or more must give notice in a prescribed manner, or, failing to do so, be liable to the town in which found for one-half the value of the goods and for the other half to the person who should sue for it. In defense to a suit for restoration of the money, defendants pleaded plaintiff\u27s failure to comply with the statute. On appeal from judgment for plaintiff, held, affirmed. The common law doctrine of treasure trove has not been merged in the statutory provisions relating to lost property, and title to treasure trove belongs to the finder as against all but the true owner. Zech v. Accola, 253 Wis. 80, 33 N.W. (2d) 232 (1948)

CONSTITUTIONAL LAW-SEARCH AND SEIZURE AS AN INCIDENT TO LAWFUL ARREST

Petitioners, suspected of carrying on an illegal lottery, had been under police observation for several months, during which time one of the petitioners maintained a room in a rooming house in the District of Columbia. On the day of the arrest, a police officer, without a warrant, but believing the unlawful lottery to be in operation, climbed through a window of the landlady\u27s room, and admitted two other officers. They proceeded to the petitioner\u27s room, where one of the officers looked through the transom. Seeing the petitioners working on an illegal lottery, the officers entered the room, arrested the petitioners and seized various articles in plain view that were used in the lottery. Petitioners made a timely motion for suppression of the evidence so seized, alleging that the seizure was a violation of their constitutional rights making the evidence inadmissible. The trial court denied the motion and the petitioners were convicted; the court of appeals affirmed. On certiorari to the United States Supreme Court, held, reversed. Even though the arrest may have been lawful, seizure of the lottery equipment without a search warrant was unreasonable and, therefore, a violation of petitioners\u27 constitutional rights. McDonald v. United States, 335 U.S. 451, 69 S.Ct. 191 (1948)